WORK MACHINE AND REMOTE SUPPORT SYSTEM

Abstract

A work machine includes a lower traveling body; an upper turning body configured to turn with respect to the lower traveling body; an attachment attached to the upper turning body and including at least a boom or an arm; an operation device including one operation lever and another operation lever; and a control part, wherein the control part controls the attachment in a first control mode when the one operation lever is operated, and the control part controls the attachment in a second control mode when the other operation lever is operated.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2023-223162, filed on Dec. 28, 2023 and Japanese Patent Application No. 2024-212903, filed on Dec. 5, 2024, the contents of which are incorporated herein by reference in their entirety.

BACKGROUND

Technical Field

The present invention relates to a work machine and a remote support system.

Description of Related Art

In the related art, there is disclosed an excavator having a machine control function which automatically operates the attachment such that the target work surface coincides with the tip position of the bucket, when data on the target work surface is input beforehand and the operator operates the operation lever while operating the switch.

SUMMARY

The work machine according to one aspect of the present invention includes a lower traveling body; an upper turning body configured to turn with respect to the lower traveling body; an attachment attached to the upper turning body and including at least a boom or an arm; an operation device including one operation lever and another operation lever; and a control part, wherein the control part controls the attachment in a first control mode when the one operation lever is operated, and the control part controls the attachment in a second control mode when the other operation lever is operated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an excavator according to a first embodiment;

FIG. 2 is a block diagram illustrating an example of the configuration of the excavator according to the first embodiment;

FIG. 3 is a diagram illustrating an example of the configuration of a hydraulic system mounted on the excavator according to the first embodiment;

FIG. 4A is a diagram illustrating a part of a hydraulic system related to the operation of an arm cylinder according to the first embodiment;

FIG. 4B is a diagram illustrating a part of the hydraulic system related to the operation of a boom cylinder according to the first embodiment;

FIG. 4C is a diagram illustrating a part of the hydraulic system related to the operation of a bucket cylinder according to the first embodiment;

FIG. 4D is a diagram illustrating a part of the hydraulic system related to the operation of a turning hydraulic motor according to the first embodiment.

FIGS. 5A to 5E are schematic diagrams illustrating an example of excavator work;

FIG. 6 is a flowchart illustrating an example of the control of an excavator according to the first embodiment;

FIG. 7 is a flowchart illustrating another example of the control of the excavator according to the first embodiment;

FIGS. 8A to 8E are schematic diagrams illustrating another example of excavator work;

FIGS. 9A and 9B are graphs illustrating an example of claw tip height control;

FIG. 10 is a flowchart illustrating yet another example of excavator control according to the first embodiment;

FIGS. 11A to 11E are schematic diagrams illustrating yet another example of excavator work;

FIGS. 12A and 12B are schematic diagrams illustrating an example of excavator work according to a second embodiment;

FIG. 13 is a flowchart illustrating one example of excavator control according to the second embodiment; and

FIG. 14 is a schematic diagram illustrating a configuration example of a remote support system for an excavator according to a third embodiment.

DETAILED DESCRIPTION

In the excavator of the related art, it is required to prepare data or the like concerning a target work surface in advance and input it to a controller of the excavator.

In view of the above problem, it is an object of the present invention to provide a work machine and a remote support system which improve work efficiency.

Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are examples, not limiting the present invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the present invention. Further, the same or corresponding components in the drawings are denoted by the same or corresponding reference numerals, and explanations may be omitted.

In the embodiments of the present invention, an example of using an excavator as a work machine will be described below, but the present invention is not limited to an excavator. The present invention may be applied to a construction machine, a standard machine, an application machine, a forestry machine, or a transport machine based on a hydraulic excavator.

First Embodiment

The embodiments of the present invention will be described below with reference to the drawings.

Outline of Excavator

First, an outline of the excavator 100 according to the first embodiment will be described with reference to FIG. 1.

FIG. 1 is a side view of the excavator 100 according to the first embodiment.

The excavator 100 according to the first embodiment includes a lower traveling body 1; an upper turning body 3 mounted on the lower traveling body 1 in a freely turning manner via a turning mechanism 2; a boom 4, an arm 5, and a bucket 6 as an attachment (work device); and a cabin 10.

The lower traveling body 1 (an example of a traveling body) includes, for example, a pair of right and left crawlers, and the respective crawlers are hydraulically driven by travel hydraulic motors 2ML and 2MR (see FIG. 2) to move the excavator 100.

The upper turning body 3 (an example of a turning body) turns with respect to the lower traveling body 1 by being driven by the turning hydraulic motor 2A (see FIG. 2).

The attachment AT (an example of an attachment) includes a boom 4, an arm 5, and a bucket 6.

The boom 4 is attached to the front center of the upper turning body 3 so as to be able to turn upward and downward, the arm 5 is attached to the tip of the boom 4 so as to be able to pivot vertically, and the bucket 6 is attached to the tip of the arm 5 so as to be able to pivot vertically.

The bucket 6 is an example of a work tool. The bucket 6 is used, for example, for excavation work. The bucket 6 according to the first embodiment has a claw tip 6a and a bottom surface 6b as parts for forming a horizontal surface.

Further, other work tools may be attached to the tip of the arm 5 in place of the bucket 6, according to the contents of work.

The boom 4, the arm 5, and the bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, a the bucket cylinder 9 as hydraulic actuators with hydraulic oil discharged from a main pump 14 (see FIG. 2).

The cabin 10 is a steering room in which an operator is seated, and the cabin 10 is mounted on the front left side of the upper turning body 3.

The excavator 100 may have a configuration in which some of the driven elements such as the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6 are electrically driven. That is, the excavator 100 may be a hybrid excavator or an electric excavator in which some of the driven elements are driven by electric actuators.

Configuration of Excavator

Next, a specific configuration of the excavator 100 will be described with reference to FIG. 2 in addition to FIG. 1.

FIG. 2 is a block diagram illustrating an example of the configuration of the excavator 100 according to the first embodiment.

In the drawings, the mechanical power line is indicated by a double line, the high-pressure hydraulic line is indicated by a solid line, the pilot line is indicated by a dashed line, and the electric drive/control line is indicated by a dotted line. The same applies to FIGS. 3 and 4.

The hydraulic drive system for hydraulically driving the hydraulic actuator of the excavator 100 according to the first embodiment includes an engine 11, a regulator 13, a main pump 14, and a control valve unit 17. The hydraulic drive system of the excavator 100 according to the first embodiment includes hydraulic actuators such as the travel hydraulic motors 2ML and 2MR, the turning hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 for hydraulically driving the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6, respectively, as described above.

The engine 11 is the main power source in the hydraulic drive system and is mounted, for example, at the rear of the upper turning body 3. Specifically, the engine 11 drives the main pump 14 and the pilot pump 15 by rotating at a predetermined constant target rotation speed under direct or indirect control by the controller (control part) 30 described later. The engine 11 is, for example, a diesel engine using light oil as fuel.

The regulator 13 controls the discharge amount of the main pump 14. For example, the regulator 13 adjusts the angle (tilt angle) of the swashplate of the main pump 14 in response to a control instruction from the controller 30. The regulator 13 includes, for example, regulators 13L and 13R as described later.

The main pump 14 (an example of a hydraulic pump) is mounted at the rear of the upper turning body 3, similar to the engine 11, for example, and supplies hydraulic oil to the control valve unit 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by the engine 11 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and as described above, the stroke length of the piston can be adjusted by adjusting the tilt angle of the swashplate by the regulator 13 under the control of the controller 30, and the discharge flow rate (discharge pressure) can be controlled. The main pump 14 includes, for example, main pumps 14L and 14R as described later. The high-pressure hydraulic line 16 is a pipe for converting power from the engine 11 into hydraulic power by the main pump 14 and conducting the hydraulic power to the control valve unit 17.

The control valve unit 17 is a hydraulic control device for controlling the hydraulic system in the excavator 100. In the first embodiment, the control valve unit 17 includes control valves 171 to 176. The control valve unit 17 is configured to selectively supply hydraulic oil discharged from the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176. The control valves 171 to 176 controls, for example, the flow rate of hydraulic oil flowing from the main pump 14 to the hydraulic actuator and the flow rate of hydraulic oil flowing from the hydraulic actuator to the hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, travel hydraulic motors 2ML and 2MR, and a turning hydraulic motor 2A. More specifically, the control valve 171 corresponds to the left-side travel hydraulic motor 2ML, the control valve 172 corresponds to the right-side travel hydraulic motor 2MR, and the control valve 173 corresponds to the turning hydraulic motor 2A. The control valve 174 corresponds to the bucket cylinder 9, the control valve 175 corresponds to the boom cylinder 7, and the control valve 176 corresponds to the arm cylinder 8.

The pilot pump 15 is an example of a pilot pressure generating device, and is configured to supply hydraulic oil to a hydraulic control device via a pilot line. In the first embodiment, the pilot pump 15 is a fixed-capacity hydraulic pump. However, the pilot pressure generating device may be implemented by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to the control valve unit 17 via a hydraulic oil line and a function of supplying hydraulic oil to various hydraulic control devices via a pilot line. In this case, the pilot pump 15 may be omitted.

The discharge pressure sensor 28 is configured to detect the discharge pressure of the main pump 14. In the first embodiment, the discharge pressure sensor 28 outputs the detected value to the controller 30.

The operation device 26 is a device used by an operator to operate an actuator. The operation device 26 includes, for example, an operation lever and an operation pedal. The actuator includes at least one of a hydraulic actuator or an electric actuator.

The proportional valve 31, which functions as a control valve for machine control, is arranged in a pipeline connecting the pilot pump 15 and the pilot port of the control valve in the control valve unit 17, and is configured such that the flow area of the pipeline can be changed. In the first embodiment, the proportional valve 31 operates according to a control instruction output from the controller 30. Therefore, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the pilot port of the control valve in the control valve unit 17 via the proportional valve 31, regardless of the operation of the operation device 26 by the operator.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a particular operation device 26 even when the operation of the particular operation device 26 is not performed.

The control system of the excavator 100 according to the first embodiment includes the controller 30, the display device D1, the input device D2, and the communication device T1. The control system of the excavator 100 includes a proportional valve 31, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a machine body inclination sensor S4, a turning angle sensor S5, an imaging device S6, a boom rod pressure sensor S7R, a boom bottom pressure sensor S7B, an arm rod pressure sensor S8R, an arm bottom pressure sensor S8B, a bucket rod pressure sensor S9R, and a bucket bottom pressure sensor S9B as a configuration related to a semi-automatic operation function.

The operation sensor 29 is configured to detect the operation contents of an operator using the operation device 26. In the first embodiment, the operation sensor 29 detects the operation direction and the operation amount of the operation device 26 corresponding to each of the actuators, and outputs the detected values to the controller 30. In the first embodiment, the controller 30 controls the opening area of the proportional valve 31 according to the output of the operation sensor 29. The controller 30 supplies the hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17. The pressure (pilot pressure) of the hydraulic oil supplied to each of the pilot ports is, in principle, the pressure corresponding to the operation direction and the operation amount of the operation device 26 corresponding to each of the hydraulic actuators. Thus, the operation device 26 is configured to supply the hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17.

The display device D1 is provided in the cabin 10 at a place easily visible to a seated operator, and displays various information images under the control of the controller 30. The display device D1 may be connected to the controller 30 via an in-vehicle communication network such as CAN (Controller Area Network) or may be connected to the controller 30 via a one-to-one exclusive-use line.

The display device D1 is not limited to a device previously provided in the cabin 10, and may be a monitor that can be placed separately. Further, the display device D1 may be any device that can display information, for example, a tablet terminal that can communicate with the communication device T1 may be used.

The input device D2 is provided within reach of a seated operator in the cabin 10, receives various operation inputs from the operator, and outputs signals corresponding to the operation inputs to the controller 30. The input device D2 includes a touch panel mounted on the display of the display device for displaying various information images, a knob switch provided at the tip of the lever part of the operation device 26, and a button switch, a lever, a toggle, a rotary dial, and the like installed around the display device D1. A signal corresponding to the operation contents to the input device D2 is taken into the controller 30.

The controller 30 (an example of a control device) is provided in the cabin 10, for example, and controls the drive of the excavator 100. The functions of the controller 30 may be implemented by any hardware, software, or combinations thereof. For example, the controller 30 is mainly composed of a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a nonvolatile auxiliary storage medium, and various input/output interfaces. The controller 30 implements various functions by executing, on the CPU, various programs stored in the ROM or nonvolatile auxiliary storage medium, for example.

For example, the controller 30 sets the target rotation speed based on operations by an operator or the like, and performs drive control to make the engine 11 rotate at a constant speed.

Also, for example, the controller 30 outputs a control instruction to the regulator 13 as needed, to change the discharge amount of the main pump 14.

Also, for example, the controller 30 controls the regulator 13 and adjusts the discharge amount of the main pump 14 based on the detected value of the pilot pressure corresponding to the operation state of various operation elements (namely, various hydraulic actuators) in the operation device 26 input from the operation sensor 29.

Also, for example, the controller 30 controls the machine guidance function for guiding the manual operation of the excavator 100 by an operator through the operation device 26. The controller 30 also controls the machine control function for automatically supporting the manual operation of the excavator 100 by an operator through the operation device 26.

Note that a part of the functions of the controller 30 may be implemented by other controllers (control devices). That is, the functions of the controller 30 may be implemented in a manner of being distributed over a plurality of controllers. For example, the machine guidance function and the machine control function may be implemented by an exclusive-use controller (control device).

More specifically, the controller 30 acquires information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the machine body inclination sensor S4, the turning angle sensor S5, the imaging device S6, the communication device T1, the input device D2, and the like. The controller 30 calculates, for example, the distance between the bucket 6 and the design surface based on the acquired information. Then, the controller 30 appropriately controls the proportional valve 31 according to the calculated distance between the bucket 6 and the design surface, and automatically adjusts the pilot pressure acting on the control valve corresponding to the hydraulic actuator individually and automatically, thereby automatically operating each actuator (see FIGS. 4A to 4D described later).

The proportional valve 31 is provided in a pilot line connecting the pilot pump 15 and one of the pilot ports of the control valves 171 to 176, and is configured such that the flow path area (cross-sectional area through which the hydraulic oil can flow) can be changed. The proportional valve 31 operates according to a control instruction input from the controller 30. Thus, even when the operation device 26 is not operated by an operator, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the proportional valve 31. The controller 30 can apply the pilot pressure generated by the proportional valve 31 to the pilot port of the corresponding control valve. The proportional valve 31 includes, for example, proportional valves 31AL, 31AR, 31BL, 31BR, 31CL, 31CR, 31DL, and 31DR, as described later.

With this configuration, even when a particular operation device 26 is not operated, the controller 30 can operate the hydraulic actuator corresponding to the particular operation device 26. Also, even when the particular operation device 26 is operated, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the particular operation device 26.

The boom angle sensor S1 is attached to the boom 4 and detects the rising angle (hereinafter, “boom angle”) of the boom 4 with respect to the upper turning body 3, for example, the angle formed by the straight line connecting the fulcrums of both ends of the boom 4 with respect to the turning plane of the upper turning body 3 in a side view. The boom angle sensor S1 may include, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an IMU (Inertial Measurement Unit), or the like. The boom angle sensor S1 may include, for example, a potentiometer using a variable resistor, and a cylinder stroke sensor for detecting the stroke amount of the hydraulic cylinder (the boom cylinder 7) corresponding to the boom angle. Hereinafter, the same applies to the arm angle sensor S2, the bucket angle sensor S3, and the machine body inclination sensor S4. The detection signal corresponding to the boom angle detected by the boom angle sensor S1 is taken into the controller 30.

The arm angle sensor S2 is attached to the arm 5 and detects the rotation angle (hereinafter, ‘arm angle’) of the arm 5 with respect to the boom 4, for example, in a side view, the angle formed by the straight line connecting the fulcrums of both ends of the arm 5 with respect to the straight line connecting the fulcrums of both ends of the boom 4. The detection signal corresponding to the arm angle detected by the arm angle sensor S2 is taken into the controller 30.

The bucket angle sensor S3 is attached to the bucket 6 and detects the rotation angle (hereinafter, “bucket angle”) of the bucket 6 with respect to the arm 5, for example, in a side view, the angle formed by the straight line connecting the fulcrum and the tip (blade edge) of the bucket 6 with respect to the straight line connecting the fulcrums of both ends of the arm 5. The detection signal corresponding to the bucket angle detected by the bucket angle sensor S3 is taken into the controller 30.

The machine body inclination sensor S4 detects the inclination state of the machine body (the upper turning body 3 or the lower traveling body 1) with respect to the horizontal surface. The machine body inclination sensor S4 is attached to the upper turning body 3, for example, and detects the inclination angle (hereinafter, “longitudinal inclination angle” and “lateral inclination angle”) of the excavator 100 (that is, the upper turning body 3) around two axes in the longitudinal and lateral directions. The detection signal corresponding to the inclination angle (the longitudinal inclination angle and the lateral inclination angle) detected by the machine body inclination sensor S4 is taken into the controller 30.

The turning angle sensor S5 outputs detection information related to the turning state of the upper turning body 3. The turning angle sensor S5 detects, for example, the turning angle speed and the turning angle of the upper turning body 3. The turning angle sensor S5 includes, for example, a gyro sensor, a resolver, a rotary encoder, etc.

The imaging device S6 captures the area around the excavator 100. The imaging device S6 includes a camera S6F for capturing an area in front of the excavator 100, a camera S6L for capturing an area to the left of the excavator 100, a camera S6R for capturing an area to the right of the excavator 100, and a camera S6B for capturing an area behind the excavator 100.

The camera S6F is attached, for example, to the ceiling of the cabin 10, that is, to the inside of the cabin 10. The camera S6F may be attached to the outside of the cabin 10, such as the roof of the cabin 10, the side face of the boom 4, etc. The camera S6L is attached to the left end of the upper surface of the upper turning body 3, the camera S6R is attached to the right end of the upper surface of the upper turning body 3, and the camera S6B is attached to the rear end of the upper surface of the upper turning body 3.

Each of the imaging devices S6 (the cameras S6F, S6B, S6L, and S6R) is, for example, a monocular wide-angle camera having a very wide angular field of view. The imaging device S6 may be a stereo camera, a distance image camera, etc. The image captured by the imaging device S6 is taken into the controller 30.

The boom rod pressure sensor S7R and the boom bottom pressure sensor S7B are respectively attached to the boom cylinder 7 and detect the pressure of the rod-side oil chamber (hereinafter, “boom rod pressure”) and the pressure of the bottom-side oil chamber (hereinafter, “boom bottom pressure”) of the boom cylinder 7. The detection signals corresponding to the boom rod pressure and the boom bottom pressure detected by the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B are each taken into the controller 30.

The arm rod pressure sensor S8R and the arm bottom pressure sensor S8B detect the pressure of the rod-side oil chamber (hereinafter, “arm rod pressure”) and the pressure of the bottom-side oil chamber (hereinafter, “arm bottom pressure”) of the arm cylinder 8. The detection signals corresponding to the arm rod pressure and the arm bottom pressure detected by the arm rod pressure sensor S8R and the arm bottom pressure sensor S8B are each taken into the controller 30.

The bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B detect the pressure of the rod-side oil chamber (hereinafter, “bucket rod pressure”) and the pressure of the bottom-side oil chamber (hereinafter, “bucket bottom pressure”) of the bucket cylinder 9. The detection signals corresponding to the bucket rod pressure and the bucket bottom pressure detected by the bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B are each taken into the controller 30.

The communication device T1 communicates with an external device through a predetermined network including a mobile communication network, a satellite communication network, an Internet network, etc., terminated at a base station. The communication device T1 is, for example, a mobile communication module corresponding to mobile communication standards such as LTE (Long Term Evolution), 4G (4th Generation), 5G (5th Generation), or the like, or a satellite communication module for connecting to a satellite communication network.

The excavator 100 operates an actuator (for example, hydraulic actuators) in response to the operation of an operator seated in the cabin 10 to drive operation elements (hereinafter, “driven elements”) such as the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6.

Instead of or in addition to being operable by an operator of the cabin 10, the excavator 100 may be configured to be remotely operable from the outside of the excavator 100. When the excavator 100 is remotely operated, the interior of the cabin 10 may be in an unmanned state.

The excavator 100 may automatically operate the actuator regardless of the operation content of the operator. Thus, the excavator 100 implements a function of automatically operation at least a part of the driven elements such as the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6, that is, what is referred to as an “automatic operation function” or a “machine control function”.

The automatic operation function may include a function to automatically operate a driven element (actuator) other than the driven element (actuator) to be operated in response to an operator's operation of the operation device 26 or a remote operation, that is, what is referred to as a “semi-automatic operation function” or an “operation-support-type machine control function”. The automatic operation function may also include a function to automatically operate at least a part of a plurality of driven elements (hydraulic actuators) on the assumption that an operator's operation of the operation device 26 or a remote operation is not performed, that is, what is referred to as a “fully automatic operation function” or a “fully automatic type machine control function”. When the fully automatic operation function is enabled in the excavator 100, the interior of the cabin 10 may be in an unmanned state. Further, the semi-automatic operation function, the fully automatic operation function, and the like may include a mode in which the operation content of the driven element (actuator) to be automatically operated is automatically determined in accordance with a predetermined rule. Further, the semi-automatic operation function, the fully automatic operation function, and the like may include a mode (what is referred to as an “automatic operation function”) in which the excavator 100 autonomously makes various determinations and autonomously determines, in accordance with the determination result, the operation content of the driven element (hydraulic actuator) to be automatically operated.

Specifically, when the operator operates the arm 5 through the operation device 26, the controller 30 may automatically operate at least one of the boom 4 or the bucket 6 such that the predetermined target design surface (hereinafter, simply referred to as a “design surface”) coincides with the tip position of the bucket 6. Further, the controller 30 may automatically operate the arm 5 regardless of the operation state of the operation device 26 operating the arm 5. That is, the controller 30 may make the attachment perform a predetermined operation by using the operator's operation of the operation device 26 as a trigger. Hereinafter, the function of the controller 30 to operate not only the arm 5 but also at least one of the boom 4 or the bucket 6 in response to the operation of the operation device 26 corresponding to the arm 5, is referred to as a “semi-automatic operation function”. The semi-automatic operation function may be executed, for example, by operating a predetermined switch (hereinafter, the “MC (Machine Control) switch”) arranged at the end of any of the lever devices (26L, 26R) included in the operation device 26.

Hydraulic System of Excavator

Next, an example configuration of the hydraulic system mounted on the excavator 100 will be described with reference to FIG. 3. FIG. 3 is a diagram illustrating an example configuration of the hydraulic system mounted on the excavator 100. FIG. 3 illustrates the mechanical power transmission system, the hydraulic oil line, the pilot line, and the electric control system by double lines, solid lines, dashed lines, and dotted lines, respectively.

The hydraulic system of the excavator 100 mainly includes an engine 11, a regulator 13, a main pump 14, a pilot pump 15, a control valve unit 17, an operation device 26, a discharge pressure sensor 28, an operation sensor 29, and a controller 30.

In FIG. 3, the hydraulic system is configured to circulate hydraulic oil from the main pump 14 driven by an engine 11 to a hydraulic oil tank via a center bypass pipeline 40 or a parallel line 42.

The main pump (hydraulic pump) 14 is configured to supply hydraulic oil to the control valve unit 17 via a hydraulic oil line. In the first embodiment, the main pump 14 is a swashplate-type variable displacement hydraulic pump.

In the first embodiment, the control valve unit 17 includes control valves (direction control valves) 171 to 176. The control valve 175 includes a control valve 175L and a control valve 175R, and the control valve 176 includes a control valve 176L and a control valve 176R. The control valve unit 17 is configured to selectively supply hydraulic oil discharged from the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176.

The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates the hydraulic oil to the hydraulic oil tank via the left-side center bypass pipeline 40L or the left parallel pipeline 42L, and the right main pump 14R circulates the hydraulic oil to the hydraulic oil tank via the right-side center bypass pipeline 40R or the right parallel pipeline 42R.

The left-side center bypass pipeline 40L is a hydraulic oil line passing through the control valves 171, 173, 175L, and 176L arranged in the control valve unit 17. The right-side center bypass pipeline 40R is a hydraulic oil line passing through the control valves 172, 174, 175R, and 176R arranged in the control valve unit 17.

The control valve 171 is a spool valve that supplies the hydraulic oil discharged from the left main pump 14L to the left-side travel hydraulic motor 2ML and switches the flow of the hydraulic oil to discharge the hydraulic oil discharged from the left-side travel hydraulic motor 2ML to the hydraulic oil tank.

The control valve 172 is a spool valve that supplies the hydraulic oil discharged from the right main pump 14R to the right-side travel hydraulic motor 2MR and switches the flow of the hydraulic oil to discharge the hydraulic oil discharged from the right-side travel hydraulic motor 2MR to the hydraulic oil tank.

The control valve 173 is a spool valve that supplies the hydraulic oil discharged from the left main pump 14L to the turning hydraulic motor 2A and switches the flow of the hydraulic oil to discharge the hydraulic oil discharged from the turning hydraulic motor 2A to the hydraulic oil tank.

The control valve 174 is a spool valve that supplies hydraulic oil discharged from the right main pump 14R to the bucket cylinder 9 and switches the flow of hydraulic oil to discharge the hydraulic oil in the bucket cylinder 9 to the hydraulic oil tank.

The control valve 175L is a spool valve that supplies hydraulic oil discharged from the left main pump 14L to the boom cylinder 7 and switches the flow of hydraulic oil to discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

The control valve 175R is a spool valve that supplies hydraulic oil discharged from the right main pump 14R to the boom cylinder 7 and switches the flow of hydraulic oil to discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

The control valve 176L is a spool valve that supplies hydraulic oil discharged from the left main pump 14L to the arm cylinder 8 and switches the flow of hydraulic oil to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

The control valve 176R is a spool valve that supplies hydraulic oil discharged from the right main pump 14R to the arm cylinder 8 and switches the flow of hydraulic oil to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

The left parallel pipeline 42L is a hydraulic oil line parallel to the left-side center bypass pipeline 40L. The left parallel pipeline 42L can supply hydraulic oil to the downstream control valve when the flow of hydraulic oil through the left-side center bypass pipeline 40L is limited or interrupted by any of the control valves 171, 173, and 175L. The right parallel pipeline 42R is a hydraulic oil line parallel to the right-side center bypass pipeline 40R. The right parallel pipeline 42R can supply hydraulic oil to the downstream control valve when the flow of hydraulic oil through the right-side center bypass pipeline 40R is limited or interrupted by any of the control valves 172, 174, and 175R.

A left turning pressure sensor S10L and a right turning pressure sensor S10R are attached to the turning hydraulic motor 2A. The left turning pressure sensor S10L detects the pressure of hydraulic oil at the left port of the turning hydraulic motor 2A. The right turning pressure sensor S10R detects the pressure of hydraulic oil at the right port of the turning hydraulic motor 2A.

The regulator 13 includes a left regulator 13L and a right regulator 13R. The left regulator 13L controls the discharge amount of the left main pump 14L by adjusting the swashplate tilt angle of the left main pump 14L according to the discharge pressure of the left main pump 14L. Specifically, the left regulator 13L reduces the discharge amount by adjusting the swashplate tilt angle of the left main pump 14L according to an increase in the discharge pressure of the left main pump 14L, for example. The same applies to the right regulator 13R. This is done such that the absorbed power (absorbed horsepower) of the main pump 14 expressed by the product of the discharge pressure and the discharge amount does not exceed the output power (output horsepower) of the engine 11.

The operation device 26 includes a left operation lever 26L, a right operation lever 26R, and a travel lever 26D. The travel lever 26D includes a left-side travel lever 26DL and a right-side travel lever 26DR.

The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR.

The left operation lever 26L is used for a turning operation and operation of the arm 5. When the left operation lever 26L is operated in the longitudinal direction, the control pressure corresponding to the lever operation amount is introduced into the pilot port of the control valve 176 by using the hydraulic oil discharged from the pilot pump 15. When operated in the lateral direction, the control pressure corresponding to the lever operation amount is introduced into the pilot port of the control valve 173 by using the hydraulic oil discharged from the pilot pump 15.

The operation sensor 29LA detects the contents of the operation of the left operation lever 26L in the longitudinal direction by the operator, and outputs the detected value to the controller 30.

The operation sensor 29LB detects the contents of the operation of the left operation lever 26L in the lateral direction by the operator, and outputs the detected value to the controller 30.

When the left operation lever 26L is operated in the arm closing direction, the controller 30 controls the proportional valve 31 according to the signal from the operation sensor 29LA to introduce the hydraulic oil to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R. When the left operation lever 26L is operated in the arm opening direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29LA to introduce hydraulic oil into the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

When the left operation lever 26L is operated in the left turning direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29LB to introduce hydraulic oil into the left pilot port of the control valve 173, and when the left operation lever 26L is operated in the right turning direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29LB to introduce hydraulic oil into the right pilot port of the control valve 173.

The left operation lever 26L is provided with a switch NS1. In the first embodiment, the switch NS1 is a push-button switch provided at the tip of the left operation lever 26L. An operator can operate the left operation lever 26L while pressing the switch NS1. The right operation lever 26R is provided with a switch NS2. In the first embodiment, the switch NS2 is a push-button switch provided at the tip of the right operation lever 26R. An operator can operate the right operation lever 26R while pressing the switch NS2. The positions where the switches NS1 and NS2 are provided are not limited to this, and the switches NS1 and NS2 may be provided at other positions in the cabin 10.

The right operation lever 26R is used to operate the boom 4 and the bucket 6. When the right operation lever 26R is operated in the longitudinal direction, the control pressure corresponding to the lever operation amount is introduced into the pilot port of the control valve 175 by using the hydraulic oil discharged from the pilot pump 15. When operated in the lateral direction, the control pressure corresponding to the lever operation amount is introduced into the pilot port of the control valve 174 by using the hydraulic oil discharged from the pilot pump 15.

The operation sensor 29RA detects the contents of the operation of the right operation lever 26R in the longitudinal direction by the operator, and outputs the detected value to the controller 30.

The operation sensor 29RB detects the contents of the operation of the right operation lever 26R in the lateral direction by the operator, and outputs the detected value to the controller 30.

Specifically, when the right operation lever 26R is operated in the boom lowering direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29RA to introduce hydraulic oil into the left pilot port of the control valve 175L and to introduce hydraulic oil into the right pilot port of the control valve 175R. When the right operation lever 26R is operated in the boom raising direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29RA to introduce hydraulic oil into the right pilot port of the control valve 175L and to introduce hydraulic oil into the left pilot port of the control valve 175R.

When the right operation lever 26R is operated in the bucket closing direction, the controller 30 controls the proportional valve 31 according to a signal from the operation sensor 29RB to introduce hydraulic oil into the right pilot port of the control valve 174, and when the right operation lever 26R is operated in the bucket opening direction, the controller 30 controls the proportional valve 31 according to a signal from the operation sensor 29RB to introduce hydraulic oil into the left pilot port of the control valve 174.

The travel lever 26D is used to operate the crawler. Specifically, the left-side travel lever 26DL is used to operate the left crawler. The travel lever 26D may be configured to be interlocked with the left travel pedal.

The operation sensor 29DL detects the content of the operation of the left-side travel lever 26DL in the longitudinal direction by the operator, and outputs the detected value to the controller 30.

When the left-side travel lever 26DL is operated in the longitudinal direction, the controller 30 controls the proportional valve 31 according to a signal from the operation sensor 29DL, and introduces a control pressure corresponding to the lever operation amount into the pilot port of the control valve 171 by using the hydraulic oil discharged from the pilot pump 15.

The right-side travel lever 26DR is used to operate the right crawler. The right-side travel lever 26DR may be configured to be interlocked with the right-side traveling pedal.

The operation sensor 29DR detects the contents of the operation of the right-side travel lever 26DR in the longitudinal direction by the operator, and outputs the detected value to the controller 30.

When the right-side travel lever 26DR is operated in the longitudinal direction, the controller 30 controls the proportional valve 31 according to the signal from the operation sensor 29DR, and introduces a control pressure corresponding to the lever operation amount to the pilot port of the control valve 172 by using the hydraulic oil discharged from the pilot pump 15.

The discharge pressure sensor 28 includes a discharge pressure sensor 28L and a discharge pressure sensor 28R. The discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L and outputs the detected value to the controller 30. The same applies to the discharge pressure sensor 28R.

The controller 30 receives the output of the operation sensor 29 and outputs a control instruction to the regulator 13 as necessary to change the discharge amount of the main pump 14. The controller 30 also receives the output of the control pressure sensor 19 provided upstream of the diaphragm (negative control diaphragm) 18 and outputs a control instruction to the regulator 13 as necessary to change the discharge amount of the main pump 14. The diaphragm 18 includes a left diaphragm 18L and a right diaphragm 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

In the left-side center bypass pipeline 40L, the left diaphragm 18L is arranged between the control valve 176L located farthest downstream and the hydraulic oil tank. Therefore, the flow of hydraulic oil discharged from the left main pump 14L is limited by the left diaphragm 18L. The left diaphragm 18L generates a control pressure for controlling the left regulator 13L. The left control pressure sensor 19L is a sensor for detecting this control pressure, and outputs the detected value to the controller 30. The controller 30 controls the discharge amount of the left main pump 14L by adjusting the swashplate tilt angle of the left main pump 14L according to this control pressure. The controller 30 decreases the discharge amount of the left main pump 14L as the control pressure increases, and increases the discharge amount of the left main pump 14L as the control pressure decreases. The discharge amount of the right main pump 14R is also controlled in the same manner.

Specifically, as illustrated in FIG. 3, when the hydraulic actuator of the excavator 100 is in the standby state where no hydraulic actuator is operated, the hydraulic oil discharged from the left main pump 14L passes through the left-side center bypass pipeline 40L and reaches the left diaphragm 18L. The flow of the hydraulic oil discharged from the left main pump 14L increases the control pressure generated upstream of the left diaphragm 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the allowable minimum discharge amount and prevents the pressure loss (pumping loss) when the discharged hydraulic oil passes through the left-side center bypass pipeline 40L. On the other hand, when any hydraulic actuator is operated, the hydraulic oil discharged from the left main pump 14L flows into the hydraulic actuator that is operated via the control valve corresponding to the hydraulic actuator that is operated. Then, the flow of the hydraulic oil discharged from the left main pump 14L decreases or eliminates the amount flowing to the left diaphragm 18L, and the control pressure generated upstream of the left diaphragm 18L is lowered. As a result, the controller 30 increases the discharge amount of the left main pump 14L, circulates sufficient hydraulic oil to the hydraulic actuator that is operated, and ensures the drive of the hydraulic actuator that is operated. The controller 30 similarly controls the discharge amount of the right main pump 14R.

With the above-described configuration, the hydraulic system of FIG. 3 can reduce wasteful energy consumption in the main pump 14 in the standby state. The wasteful energy consumption includes pumping loss generated in the center bypass pipeline 40 caused by the hydraulic oil discharged from the main pump 14. When the hydraulic actuator is operated, the hydraulic system of FIG. 3 can reliably supply necessary and sufficient hydraulic oil from the main pump 14 to the hydraulic actuator that is operated.

That is, the controller 30 controls the regulator 13 such that the discharge amount becomes the smaller of the first discharge amount calculated such that the absorbed power (absorbed horsepower) of the main pump 14 expressed as the product of discharge pressure and discharge amount does not exceed the output power (output horsepower) of the engine 11 and the second discharge amount calculated based on the control pressure detected by the control pressure sensor 19.

Next, with reference to FIGS. 4A to 4D, the configuration in which the controller 30 operates the actuator by the machine control function will be described. FIGS. 4A to 4D are partial views of the hydraulic system. Specifically, FIG. 4A is a partial view of the hydraulic system relating to the operation of the arm cylinder 8, and FIG. 4B is a partial view of the hydraulic system relating to the operation of the boom cylinder 7. FIG. 4C is a partial view of the hydraulic system relating to the operation of the bucket cylinder 9, and FIG. 4D is a partial view of the hydraulic system relating to the operation of the turning hydraulic motor 2A.

As illustrated in FIGS. 4A to 4D, the hydraulic system includes a proportional valve 31. The proportional valve 31 includes proportional valves 31AL to 31DL and 31AR to 31DR.

For example, as illustrated in FIG. 4A, the left operation lever 26L is used to operate the arm 5. Specifically, the left operation lever 26L uses hydraulic oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to a longitudinal operation to the pilot port of the control valve 176. More specifically, when the left operation lever 26L is operated in the arm closing direction (backward direction), the controller 30 causes the pilot pressure corresponding to the operation amount to be applied to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. When the left operation lever 26L is operated in the arm opening direction (forward direction), the controller 30 causes the pilot pressure corresponding to the operation amount to be applied to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

The left operation lever 26L is provided with a switch NS1.

The operation sensor 29LA detects the operation content of the left operation lever 26L in the longitudinal direction by the operator, and outputs the detected value to the controller 30.

The proportional valve 31AL operates according to the control instruction (current instruction) output by the controller 30. The pilot pressure is adjusted by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL. The proportional valve 31AR operates according to the control instruction (current instruction) output by the controller 30. The pilot pressure is adjusted by hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR. The proportional valve 31AL can adjust the pilot pressure such that the control valve 176L and the control valve 176R can stop at any valve position. Similarly, the proportional valve 31AR can adjust the pilot pressure such that the control valve 176L and the control valve 176R can stop at any valve position.

The pilot line connecting the proportional valve 31AL and one port of the control valve 176 (the right port of the control valve 176L and the left port of the control valve 176R) is provided with a pilot pressure sensor 32AL for detecting the pilot pressure. The pilot line connecting the proportional valve 31AR and the other port of the control valve 176 (the left port of the control valve 176L and the right port of the control valve 176R) is provided with a pilot pressure sensor 32AR for detecting the pilot pressure. The values detected by the pilot pressure sensors 32AL and 32AR are transmitted to the controller 30.

With this configuration, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL in response to the arm closing operation by the operator. The controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL regardless of the arm closing operation by the operator. That is, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or regardless of the arm closing operation by the operator.

In response to the arm opening operation by the operator, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR. Further, regardless of the arm opening operation by the operator, the controller 30 can supply hydraulic oil, discharged from the pilot pump 15, to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR. That is, the controller 30 can open the arm 5 in response to the arm opening operation by the operator or regardless of the arm opening operation by the operator.

With this configuration, even when the arm closing operation by the operator is performed, the controller 30 can, if necessary, reduce the pilot pressure acting on the pilot port on the closed side of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) and forcibly stop the closing operation of the arm 5. The same applies to the case of forcibly stopping the opening operation of the arm 5 when the arm opening operation by the operator is performed.

Alternatively, even when the arm closing operation by the operator is performed, the controller 30 may forcibly stop the closing operation of the arm 5, according to need, by controlling the proportional valve 31AR, increasing the pilot pressure acting on the pilot port on the open side of the control valve 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) on the opposite side of the pilot port on the closed side of the control valve 176 and forcibly returning the control valve 176 to the neutral position. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the arm opening operation is performed by the operator.

Although descriptions with reference to FIGS. 4B to 4D will be omitted, the same applies to the case where the operation of the boom 4 is forcibly stopped when the boom raising operation or the boom lowering operation is performed by the operator, the case where the operation of the bucket 6 is forcibly stopped when the bucket closing operation or the bucket opening operation is performed by the operator, and the case where the turning operation of the upper turning body 3 is forcibly stopped when the turning operation is performed by the operator. The same applies to the case where the traveling operation of the lower traveling body 1 is forcibly stopped when the traveling operation is performed by the operator.

As illustrated in FIG. 4B, the right operation lever 26R is used to operate the boom 4. Specifically, the right operation lever 26R uses hydraulic oil discharged from the pilot pump 15 to apply pilot pressure corresponding to the operation in the longitudinal direction, to the pilot port of the control valve 175. More specifically, when the right operation lever 26R is operated in the boom raising direction (backward direction), the controller 30 applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 175R. When the right operation lever 26R is operated in the boom lowering direction (forward direction), the controller 30 applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R.

The right operation lever 26R is provided with a switch NS2.

The operation sensor 29RA detects the operation content of the right operation lever 26R by the operator in the longitudinal direction, and outputs the detected value to the controller 30.

The proportional valve 31BL operates according to the control instruction (current instruction) output from the controller 30. The pilot pressure is adjusted by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL. The proportional valve 31BR operates according to the control instruction (current instruction) output from the controller 30. The pilot pressure is adjusted by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR. The proportional valve 31BL can adjust the pilot pressure such that the control valve 175R can stop at any valve position. The proportional valve 31BR can adjust the pilot pressure such that the control valve 175R can stop at any valve position.

The pilot line connecting the proportional valve 31BL and one port of the control valve 175 (the left port of the control valve 175R) is provided with a pilot pressure sensor 32BL for detecting the pilot pressure. The pilot line connecting the proportional valve 31BR and the other port of the control valve 175 (the right port of the control valve 175R) is provided with a pilot pressure sensor 32BR for detecting the pilot pressure. The values detected by the pilot pressure sensors 32BL and 32BR are transmitted to the controller 30.

With this configuration, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL in response to the boom raising operation by the operator. The controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL regardless of the boom raising operation by the operator. That is, the controller 30 can raise the boom 4 in response to the boom raising operation by the operator or regardless of the boom raising operation by the operator.

The controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR in response to the boom lowering operation by the operator. Further, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR regardless of the boom lowering operation by the operator. That is, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator or regardless of the boom lowering operation by the operator.

In FIG. 4B, the controller 30 controls the proportional valves 31BL and 31BR and supplies the pilot pressure to the control valve 175R. Similarly, the controller 30 controls the proportional valve (not illustrated) and supplies the pilot pressure to the control valve 175L.

As illustrated in FIG. 4C, the right operation lever 26R is also used to operate the bucket 6. Specifically, the right operation lever 26R uses the hydraulic oil discharged from the pilot pump 15 to apply the pilot pressure corresponding to the lateral operation, to the pilot port of the control valve 174. More specifically, when the right operation lever 26R is operated in the bucket closing direction (left direction), the controller 30 applies the pilot pressure corresponding to the operation amount to the left pilot port of the control valve 174. When the right operation lever 26R is operated in the bucket opening direction (right direction), the controller 30 applies the pilot pressure corresponding to the operation amount to the right pilot port of the control valve 174.

The right operation lever 26R is provided with a switch NS2.

The operation sensor 29RB detects the operation content of the right operation lever 26R in the lateral direction by the operator, and outputs the detected value to the controller 30.

The proportional valve 31CL operates according to the control instruction (current instruction) output from the controller 30. The pilot pressure is adjusted by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL. The proportional valve 31CR operates according to the control instruction (current instruction) output from the controller 30. The pilot pressure is adjusted by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR. The proportional valve 31CL can adjust the pilot pressure such that the control valve 174 can be stopped at any valve position. Similarly, the proportional valve 31CR can adjust the pilot pressure such that the control valve 174 can be stopped at any valve position.

The pilot line connecting the proportional valve 31CL and one port of the control valve 174 (the left port of the control valve 174) is provided with a pilot pressure sensor 32CL for detecting the pilot pressure. The pilot line connecting the proportional valve 31CR and the other port of the control valve 174 (the right port of the control valve 174) is provided with a pilot pressure sensor 32CR for detecting the pilot pressure. The values detected by the pilot pressure sensors 32CL and 32CR are transmitted to the controller 30.

With this configuration, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL in response to the bucket closing operation by the operator. The controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL regardless of the bucket closing operation by the operator. That is, the controller 30 can close the bucket 6 in response to the bucket closing operation by the operator or regardless of the bucket closing operation by the operator.

Also, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR in response to the bucket opening operation by the operator. Also, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR regardless of the bucket opening operation by the operator. That is, the controller 30 can open the bucket 6 in response to the bucket opening operation by the operator or regardless of the bucket opening operation by the operator.

As illustrated in FIG. 4D, the left operation lever 26L is also used to operate the turning mechanism 2. Specifically, the left operation lever 26L uses hydraulic oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the lateral direction, to the pilot port of the control valve 173. More specifically, when the left operation lever 26L is operated in the left turning direction (left direction), the controller 30 applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 173. When the left operation lever 26L is operated in the right turning direction (right direction), the controller 30 applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 173.

The left operation lever 26L is provided with a switch NS1.

The operation sensor 29LB detects the operation content of the left operation lever 26L in the lateral direction by the operator, and outputs the detected value to the controller 30.

The proportional valve 31DL operates according to the control instruction (current instruction) output from the controller 30. The pilot pressure is adjusted by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL. The proportional valve 31DR operates according to the control instruction (current instruction) output from the controller 30. The pilot pressure is adjusted by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR. The proportional valve 31DL can adjust the pilot pressure such that the control valve 173 can stop at any valve position. Similarly, the proportional valve 31DR can adjust the pilot pressure such that the control valve 173 can stop at any valve position.

A pilot pressure sensor 32DL for detecting pilot pressure is provided in the pilot line connecting the proportional valve 31DL and one port of the control valve 173 (the left port of the control valve 173). A pilot pressure sensor 32DR for detecting pilot pressure is provided in the pilot line connecting the proportional valve 31DR and the other port of the control valve 173 (the right port of the control valve 173). Values detected by the pilot pressure sensors 32DL and 32DR are transmitted to the controller 30.

With this configuration, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL in response to the left turning operation by the operator. The controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL regardless of the left turning operation by the operator. That is, the controller 30 can turn the turning mechanism 2 to the left in response to the left turning operation by the operator or regardless of the left turning operation by the operator.

The controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR in response to the right turning operation by the operator. The controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR regardless of the right turning operation by the operator. That is, the controller 30 can turn the turning mechanism 2 to the right in response to the right turning operation by the operator or regardless of the right turning operation by the operator.

The excavator 100 may be configured to automatically advance and reverse the lower traveling body 1. In this case, the hydraulic system part relating to the operation of the left-side travel hydraulic motor 2ML and the hydraulic system part relating to the operation of the right-side travel hydraulic motor 2MR may be configured in the same manner as the hydraulic system part relating to the operation of the boom cylinder 7.

Further, although an electric operation lever has been described as the form of the operation device 26, a hydraulic operation lever may be adopted instead of an electric operation lever. In this case, the lever operation amount of the hydraulic operation lever may be detected in the form of pressure by a pressure sensor and input to the controller 30. Moreover, a solenoid valve may be arranged between the operation device 26 as the hydraulic operation lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electric signal from the controller 30. With this configuration, when manual operation is performed by using the operation device 26 as the hydraulic operation lever, the operation device 26 can move each control valve by increasing or decreasing the pilot pressure according to the lever operation amount. Each control valve may be constituted by an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electric signal from the controller 30 corresponding to the lever operation amount of the electric operation lever.

Example of Operation of Excavator

Next, an example of operation using the excavator 100 will be described with reference to FIGS. 5A to 5E. FIGS. 5A to 5E are schematic views illustrating an example of operation using the excavator 100. Here, an example of excavating the ground to form a substantially rectangular recessed part 800 in the ground will be described.

An operator operates the excavator 100 to excavate the ground to form an approximate shape of the recessed part 800. Then, a vertical surface (side surface) 801, a horizontal surface (bottom surface) 802, and a vertical surface (side surface) 803 of the recessed part 800 are excavated such that the recessed part 800 has the desired shape.

First, as illustrated in FIGS. 5A and 5B, the excavator 100 excavates one vertical surface 801 (the side surface on the back side as viewed from the excavator 100 and the side surface on the left side as viewed in FIGS. 5A to 5E) of the plurality of side surfaces of the recessed part 800 by vertically lowering the bucket 6.

Next, as illustrated in FIGS. 5B and 5C, the excavator 100 excavates the horizontal surface 802 of the recessed part 800 by horizontally moving the bucket 6.

Next, as illustrated in FIGS. 5C and 5D, the operator adjusts the angle of the bucket 6.

Then, as illustrated in FIGS. 5D and 5E, the excavator 100 excavates the other vertical surface 803 (a side surface on the front side as viewed from the excavator 100 and a side surface on the right side as viewed in FIGS. 5A to 5E) of the plurality of side surfaces of the recessed part 800 by vertically raising the bucket 6.

The operation for making the excavator 100 perform such operations of vertically lowering, horizontally moving, and vertically raising the bucket 6 is a combined operation of simultaneously operating the boom 4, the arm 5, and the like, and requires skill of the operator. In the case of an operator who is not skilled in operations, there is a possibility of having to redo the operation. In the case of an excavator having a machine control function which inputs data on the target work surface in advance and automatically operates the attachment such that the target work surface coincides with the tip position of the bucket, there is a problem that it requires time and effort to create and input data on the target work surface.

Next, an example of the control in the excavator 100 according to the first embodiment will be described with reference to FIG. 6. FIG. 6 is a flowchart illustrating an example of the control in the excavator 100 according to the first embodiment.

In step S101, the controller 30 determines whether or not the switches NS1 and NS2 are operated. Here, the switches NS1 and NS2 are switches for selecting whether or not to enable the machine control function. The switches NS1 and NS2 may be momentary switches that turn ON only while the switches NS1 and NS2 are pressed and turn OFF when the switches NS1 and NS2 are released. Further, the switches NS1 and NS2 may be alternate switches that turn ON and OFF each time the switches NS1 and NS2 are pressed. Also, the switches NS1 and NS2 may be operated by operating either switch or both switches.

When the switches NS1 and NS2 are not operated (NO in step S101), that is, when the switches NS1 and NS2 are in the OFF state, the process of the controller 30 proceeds to step S102.

In step S102, the controller 30 determines that regular control (regular mode) is to be performed. That is, when the operator operates the operation device 26, the controller 30 controls the attachment AT in the regular control mode (refer to the operation directions of the left operation lever 26L and the right operation lever 26R and the operation of the attachment AT illustrated in FIG. 3). Specifically, when the operator operates the left operation lever 26L in the longitudinal direction, the controller 30 controls the control valve 176 which supplies hydraulic oil to the arm cylinder 8, via the proportional valves 31AL and 31AR. As a result, the arm 5 of the attachment AT operates (opens and closes). When the operator operates the right operation lever 26R in the longitudinal direction, the controller 30 controls the control valve 175 which supplies hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR. As a result, the boom 4 of the attachment AT operates (opens and closes). Further, when the operator operates the right operation lever 26R in the lateral direction, the controller 30 controls the control valve 174 which supplies the hydraulic oil to the bucket cylinder 9 via the proportional valves 31CL and 31CR. As a result, the bucket 6 of the attachment AT operates (opens and closes).

On the other hand, when the switches NS1 and NS2 are operated (YES in step S101), that is, when the switches NS1 and NS2 are in the ON state, the controller 30 proceeds to step S103.

In step S103, the controller 30 determines whether or not one of the operation levers is operated. Here, the controller 30 determines whether or not the left operation lever 26L is operated in one of the lateral directions (opening or closing direction of the arm 5). When one of the operation levers is not operated (NO in step S103), the controller 30 proceeds to step S107.

When one of the operation levers is operated (YES in step S103), the controller 30 proceeds to step S104. Here, as indicated in steps S104 to S106, which will be described later, the controller 30 controls the attachment AT in the first control mode in which the reference position of the attachment AT is horizontally moved by the longitudinal operation of the left operation lever 26L. Here, the reference position is the position of the claw tip 6a of the bucket 6.

In step S104, the controller 30 determines whether or not the angle of the bottom surface 6b of the bucket 6 is within a predetermined range. Here, it determines whether or not the angle θ1 formed by the horizontal direction and the bottom surface 6b of the bucket 6 is within a predetermined range (for example, a range of −2°≤θ1≤+2°). That is, the controller 30 determines whether or not the bottom surface 6b of the bucket 6 is substantially horizontally oriented.

If the angle of the bottom surface 6b of the bucket 6 is within the predetermined range (YES in step S104), the controller 30 proceeds to step S105. In step S105, the controller 30 maintains the angle of the bottom surface 6b of the bucket 6 and controls the attachment AT in the control mode of moving the bucket 6 (the claw tip 6a). Specifically, the controller 30 controls the control valve 176 that supplies hydraulic oil to the arm cylinder 8 via the proportional valves 31AL and 31AR by the operator operating the left operation lever 26L in the longitudinal direction. Thus, the arm 5 of the attachment AT operates (opens and closes). Further, the controller 30 automatically controls the control valve 175 for supplying hydraulic oil to the boom cylinder 7 and the control valve 174 for supplying hydraulic oil to the bucket cylinder 9 via the proportional valves 31BL, 31BR and 31CL, 31CR so as to move the bucket 6 (the claw tip 6a) while maintaining the angle of the bottom surface 6b of the bucket 6. That is, the controller 30 controls the operation of the arm 5 based on the amount of operation in the longitudinal direction of the left operation lever 26L. In accordance with the operation of the arm 5, the controller 30 automatically controls the operation of the boom 4 and the bucket 6 so as to move the bucket 6 (the claw tip 6a) while maintaining the angle of the bottom surface 6b of the bucket 6.

The shape information of the attachment AT (shape information of the boom 4, shape information of the arm 5, shape information of the bucket 6 (end attachment)) is input to the controller 30 in advance. The controller 30 calculates the position of the claw tip 6a and the angle of the bottom surface 6b of the bucket 6 based on the angle of each joint of the attachment AT detected by the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 and the shape information of the attachment AT.

Further, the horizontal direction may be the actual horizontal direction detected by the machine body inclination sensor S4, and the direction on the plane orthogonal to the turning axis of the upper turning body 3 may be the horizontal direction, assuming that the excavator 100 is arranged on the horizontal (approximately horizontal) ground. The vertical direction may be the direction perpendicular to the horizontal direction, and the actual vertical direction detected by the machine body inclination sensor S4, and the direction parallel to the turning axis of the upper turning body 3 may be the vertical direction, assuming that the excavator 100 is arranged on the horizontal (approximately horizontal) ground.

If the angle of the bottom surface 6b of the bucket 6 is not within the predetermined range (NO in step S104), the process of the controller 30 proceeds to step S106. In step S106, the controller 30 controls the attachment AT in a control mode in which the claw tip 6a is moved horizontally. Specifically, when the operator operates the left operation lever 26L in the longitudinal direction, the controller 30 controls the control valve 176 which supplies hydraulic oil to the arm cylinder 8, via the proportional valves 31AL and 31AR. As a result, the arm 5 of the attachment AT operates (opens and closes). In addition, the controller 30 automatically controls the control valve 175 which supplies hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR so as to move the claw tip 6a horizontally. Here, the opening and closing angle of the bucket 6 with respect to the arm 5 is maintained. That is, the controller 30 controls the operation of the arm 5 based on the amount of operation of the left operation lever 26L in the longitudinal direction. In accordance with the operation of the arm 5, the controller 30 automatically controls the operation of the boom 4 so as to move the claw tip 6a horizontally.

If one of the operation levers is not operated (NO in S103), the controller 30 proceeds to step S107.

In step S107, the controller 30 determines whether or not the other operation lever is operated. Here, the controller 30 determines whether or not the right operation lever 26R is operated in one of the lateral directions (boom lowering or raising direction of the boom 4). If the other operation lever is not operated (NO in S107), the controller 30 returns to step S103.

If the other operation lever is operated (YES in S107), the controller 30 proceeds to step S108. Here, as indicated in steps S108 to S110, which will be described later, the controller 30 controls the attachment AT in a second control mode in which the reference position of the attachment AT is vertically moved by the longitudinal operation of the right operation lever 26R. Here, the reference position is the position of the claw tip 6a of the bucket 6.

In step S108, the controller 30 determines whether or not the angle of the bottom surface 6b of the bucket 6 is within a predetermined range. Here, it is determined whether or not the angle θ2 formed by the vertical direction and the bottom surface 6b of the bucket 6 is within a predetermined range (for example, a range of −2°≤θ2≤+2°). That is, it is determined whether or not the bottom surface 6b of the bucket 6 is oriented in a substantially vertical direction.

If the angle of the bottom surface 6b of the bucket 6 is within a predetermined range (YES in step S108), the controller 30 proceeds to step S109. In step S109, the controller 30 controls the attachment AT in a control mode to move the bucket 6 (the claw tip 6a) while maintaining the angle of the bottom surface 6b of the bucket 6. Specifically, the controller 30 controls the control valve 175 for supplying hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR when the operator operates the right operation lever 26R in the longitudinal direction. As a result, the boom 4 of the attachment AT operates (opens and closes). In addition, the controller 30 automatically controls the control valve 176 for supplying hydraulic oil to the arm cylinder 8 and the control valve 174 for supplying hydraulic oil to the bucket cylinder 9, via the proportional valves 31AL and 31AR and the proportional valves 31CL and 31CR so as to move the bucket 6 (the claw tip 6a) while maintaining the angle of the bottom surface 6b of the bucket 6. That is, the controller 30 controls the operation of the boom 4 based on the amount of operation of the right operation lever 26R in the longitudinal direction. In accordance with the operation of the boom 4, the controller 30 automatically controls the operation of the boom 4 and the bucket 6 so as to move the bucket 6 (the claw tip 6a) while maintaining the angle of the bottom surface 6b of the bucket 6.

If the angle of the bottom surface 6b of the bucket 6 is not within the predetermined range (NO in step S108), the process of the controller 30 proceeds to step S110. In step S110, the controller 30 controls the attachment AT in the control mode of vertically moving the claw tip 6a. Specifically, when the operator operates the right operation lever 26R in the longitudinal direction, the controller 30 controls the control valve 175 which supplies hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR. As a result, the boom 4 of the attachment AT operates (opens and closes). In addition, the controller 30 automatically controls the control valve 176 which supplies hydraulic oil to the arm cylinder 8, via the proportional valves 31AL and 31AR so as to move the claw tip 6a vertically. Here, the opening and closing angle of the bucket 6 with respect to the arm 5 is maintained. That is, the controller 30 controls the operation of the boom 4 based on the amount of operation in the longitudinal direction of the right operation lever 26R. In accordance with the operation of the boom 4, the controller 30 automatically controls the operation of the boom 4 so as to move the claw tip 6a vertically.

As described above, according to the excavator 100 according to the first embodiment, even an operator who is not skilled in operations the excavator 100 can easily move the reference position (the position of the claw tip 6a) of the bucket 6 in the horizontal and vertical directions by operating one operation lever (26L, 26R).

For example, the operator first operates the excavator 100 in the regular mode to move the position of the claw tip 6a of the bucket 6 to the position illustrated in FIG. 5A.

Next, the controller 30 lowers the claw tip 6a of the bucket 6 in the vertical direction by operating the right operation lever 26R in the forward direction (boom lowering) while operating the switches NS1 and NS2 (for example, the switch NS2 provided on the right operation lever 26R) by the operator. Thus, a vertical surface 801 is formed and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 5B.

Next, the controller 30 moves the claw tip 6a of the bucket 6 in the horizontal direction by operating the left operation lever 26L in the backward direction (arm closing) while operating the switches NS1 and NS2 (for example, the switch NS1 provided on the left operation lever 26L) by the operator. Thus, a horizontal surface 802 is formed and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 5C.

Next, the operator operates the excavator 100 in the regular mode to adjust the angle of the bucket 6. Thus, the angle of the bucket 6 is adjusted to the position illustrated in FIG. 5D.

Next, the operator operates the switches NS1 and NS2 (for example, the switch NS2 provided on the right operation lever 26R) and operates the right operation lever 26R in the rearward direction (boom raising), such that the controller 30 raises the claw tip 6a of the bucket 6 in the vertical direction. Thus, the vertical surface 803 is formed, and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 5E.

Thus, the work of forming the recessed part 800 having the vertical surfaces 801, 803 and the horizontal surface 802 illustrated in FIGS. 5A to 5E can be easily performed. Moreover, the labor of preparing and inputting data on the target work surface can be eliminated.

In a state where the bottom surface 6b of the bucket 6 can be regarded as substantially horizontal, by operating the switches NS1 and NS2 (for example, the switch NS1 provided on the left operation lever 26L) and operating the left operation lever 26L in the longitudinal direction, the reference position (the position of the claw tip 6a) of the bucket 6 can be horizontally moved while maintaining the bottom surface 6b of the bucket 6 substantially horizontal (S105). Thus, a horizontal surface that is compacted by the bottom surface 6b of the bucket 6 can be formed.

Similarly, in a state where the bottom surface 6b of the bucket 6 can be regarded as substantially vertical, by operating the switches NS1 and NS2 (for example, the switch NS2 provided on the right operation lever 26R) and operating the right operation lever 26R in the longitudinal direction, the reference position (the position of the claw tip 6a) of the bucket 6 can be vertically moved while maintaining the bottom surface 6b of the bucket 6 substantially vertical (S110). Thus, a more favorable vertical surface can be formed.

Further, when the left operation lever 26L is operated in the longitudinal direction while operating the switch NS1 (first switch) of the left operation lever 26L, the attachment AT is controlled in the first control mode that moves the reference position of the attachment AT in the horizontal direction. Further, when the right operation lever 26R is operated in the longitudinal direction while operating the switch NS2 (second switch) of the right operation lever 26R, the attachment AT is controlled in the second control mode that moves the reference position of the attachment AT in the vertical direction. Thus, it is possible to easily move the reference position of the attachment AT in the horizontal direction or the vertical direction while preventing misoperation.

Further, the controller 30 may be configured to move the claw tip 6a of the bucket 6 in the transverse direction by operating the left operation lever 26L in the lateral direction (turn left, turn right) while operating the switches NS1 and NS2 by the operator. That is, the controller 30 controls the attachment AT in a third control mode in which the reference position of the attachment AT is moved in the transverse direction by operating the left operation lever 26L in the lateral direction. Here, the reference position is the position of the claw tip 6a of the bucket 6. In this third control mode, the controller 30 may perform control to stop the bottom surface 6b of the bucket 6 in the horizontal or vertical position.

Another Example of Operation of the Excavator

Next, another example of work performed by using the excavator 100 will be described with reference to FIGS. 7 and 8. FIG. 7 is a flowchart illustrating another example of control in the excavator 100 according to the first embodiment. FIGS. 8A to 8E are schematic diagrams illustrating another example of work performed by using the excavator 100. In this example, a horizontal surface 802 is formed on the ground by repeating horizontal pulling of the bucket 6 with the claw tip 6a at the same height.

The operator operates the operation device 26 (the left operation lever 26L, the right operation lever 26R) to move the claw tip 6a of the bucket 6 to the excavation start position. That is, the claw tip 6a of the bucket 6 is adjusted to a predetermined height position (first height position, initial position with respect to the first control mode). For example, the operator first operates the excavator 100 in the regular mode (see S102) to move the claw tip 6a of the bucket 6 to the position illustrated in FIG. 8A.

In step S121, the operator performs an arm pulling operation (arm closing operation, the left operation lever 26L is tilted to the arm closing side (rear side)) while pressing the left lever switch (the switch NS1 of the left operation lever 26L).

Here, when the left lever switch is operated and the arm pulling operation is input (YES in S101, YES in S103), the controller 30 controls the attachment AT in a control mode (the first control mode, see S105 or S106) in which the claw tip 6a is held at the first height position and moved horizontally. Thus, the bucket 6 is pulled horizontally. At this time, when controlling the attachment AT in the first control mode, the controller 30 stores the height position (first height position, initial position with respect to the first control mode) of the claw tip 6a during the arm pulling operation in a storage part (not illustrated) of the controller 30. Thus, a horizontal surface 802 is formed, and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 8B.

In step S122, the operator operates the attachment AT in the regular mode (see S102). The left lever switch (the switch NS1 of the left operation lever 26L) and the right lever switch (the switch NS2 of the right operation lever 26R) are not operated (NO in S101), and the controller 30 controls the attachment AT in the regular control mode (S102). Thus, the claw tip 6a of the bucket 6 is moved to the position above the next excavation position. For example, the operator operates the operation device 26 to perform a boom raising operation to move the claw tip 6a of the bucket 6 away from the horizontal surface 802. Then, the operator operates the operation device 26 to perform an arm opening operation to move the claw tip 6a of the bucket 6 to the position above the next excavation position (the second height position). The second height position is a position higher than the first height position (a position away from the horizontal surface 802). Thus, the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 8C.

In step S122, the attachment AT is operated to move the claw tip 6a of the bucket 6 to a position above the next excavation position, but this is not limited. For example, when a horizontal surface 802 having a fan shape or an annular shape when viewed from above is formed, hydraulic oil may be supplied to the turning hydraulic motor 2A to turn the upper turning body 3. Further, when a long horizontal surface 802 is formed, hydraulic oil may be supplied to the travel hydraulic motors 2ML and 2MR to move the excavator 100 (the lower traveling body 1).

Further, even if the lower traveling body 1 of the excavator 100 travels or turns, the controller 30 retains the stored height position (the first height position, the initial position with respect to the first control mode) of the claw tip 6a in the storage part without being reset. Further, even if the upper turning body 3 of the excavator 100 turns, the controller 30 retains the stored height position (the first height position, the initial position with respect to the first control mode) of the claw tip 6a in the storage part without being reset.

In step S123, the operator performs a boom lowering operation (the right operation lever 26R is tilted to the boom lowering side (front side)) while pressing the right lever switch (the switch NS2 of the right operation lever 26R). Here, the controller 30 controls the attachment AT in a control mode (fourth control mode) for lowering the claw tip 6a to the first height position stored in step S121. When the claw tip 6a reaches the first height position, the height position of the claw tip 6a remains at the first height position and does not fall below the first height position even if the boom lowering operation is performed while continuously pressing the right lever switch.

Here, when a boom lowering operation is input while pressing the right lever switch, the controller 30 controls the attachment AT in a regular control mode (see S102) to lower the boom 4. Also, the controller 30 detects the height position of the claw tip 6a based on, for example, a sensor (the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3) that detects the posture of the attachment AT. The controller 30 lowers the boom 4 by the boom lowering operation until the detected height position of the claw tip 6a becomes the first height position stored in step S121. On the other hand, when the detected height position of the claw tip 6a becomes the first height position stored in step S121, the controller 30 controls the boom 4 to not be lowered further even if the boom lowering operation is performed. Thus, the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 8D.

Alternatively, when the boom lowering operation is input while pressing the right lever switch, the controller 30 controls the attachment AT in a control mode (see S109 or S110) that vertically moves the claw tip 6a. Further, the controller 30 detects the height position of the claw tip 6a based on, for example, a sensor (the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3) that detects the posture of the attachment AT. The controller 30 vertically lowers the claw tip 6a by the boom lowering operation until the detected height position of the claw tip 6a becomes the first height position stored in step S121. On the other hand, when the detected height position of the claw tip 6a becomes the first height position stored in step S121, the controller 30 controls the claw tip 6a such that the claw tip 6a is not lowered further even if the boom lowering operation is performed. Thus, the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 8D.

In step S123, the excavator 100 may include a switch (an example of the input device D2) that switches between the regular control mode for lowering the boom 4 and the control mode for vertically moving the claw tip 6a. This switch (an example of the input device D2) may be any of a touch panel mounted on the display of the display device for displaying various information images, a knob switch provided at the tip of the lever part of the operation device 26, a button switch, a lever, a toggle, a rotary dial or the like installed around the display device D1. Further, the selection result of the switch may be displayed on the display device D1.

In step S124, the operator performs an arm pulling operation (arm closing operation, the left operation lever 26L is tilted to the arm closing side (rear side)) while pressing the left lever switch (the switch NS1 of the left operation lever 26L).

Here, when the left lever switch is operated and the arm pulling operation is input (YES in S101, YES in S103), the controller 30 controls the attachment AT in a control mode (the first control mode, see S105 or S106.) in which the claw tip 6a is held at the first height position and moved horizontally. Thus, the bucket 6 is horizontally pulled. At this time, the controller 30 stores the height position (first height position, initial position with respect to the first control mode) of the claw tip 6a at the time of the arm pulling operation in the storage part (not illustrated) of the controller 30. Thus, a horizontal surface 802 is formed, and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 8E.

When the horizontal pulling of the bucket 6 is further repeated, the processing of steps S122 to S124 is repeated.

Thus, the horizontal pulling of the bucket 6 can be performed at the same height position (the first height position, the initial position with respect to the first control mode) of the claw tip 6a in steps S121 and S124. That is, when the height position of the claw tip 6a is adjusted before starting the second horizontal pulling of the bucket 6 (S124), the height position can be easily adjusted to the height position of the claw tip 6a in the first horizontal pulling of the bucket 6 (S121).

By repeating the horizontal pulling of the bucket 6 at the same position, the surface accuracy of the horizontal surface 802 can be improved.

Further, by accompanying the turning of the upper turning body 3 and/or the movement of the excavator 100 in step S122, a wide horizontal surface 802 can be formed. For example, by retreating the excavator 100 in step S122, the bottom surface (horizontal surface 802) of a long groove can be formed.

Note that the controller 30 has been described as controlling the attachment AT in a fourth control mode for lowering the claw tip 6a to the stored first height position when a predetermined first operation (lower the boom while pressing the right lever switch) is input in step S123, but this is not limited thereto. The predetermined first operation may be input of a predetermined switch or input of a predetermined voice to a voice input part (not illustrated) provided in the cabin 10. The fourth control mode may be configured to automatically lower the claw tip 6a to the stored first height position when a predetermined first operation is input.

The excavator 100 may include a switch (an example of the input device D2) for resetting the stored height position (first height position) of the claw tip 6a. The switch (an example of the input device D2) may be any of a touch panel mounted on the display of a display device for displaying various information images, a knob switch provided at the tip of the lever part of the operation device 26, a button switch, a lever, a toggle, a rotary dial, or the like installed around the display device D1. The result of the selection of the switch may be displayed on the display device D1.

When the left lever switch is operated and the arm pulling operation is input while the claw tip 6a is placed at another height position (new excavation start position) (see S121), the controller 30 overwrites and stores the height position of the claw tip 6a at the time of the arm pulling operation (the first height position, the initial position with respect to the first control mode) in the storage part (not illustrated) of the controller 30.

FIGS. 9A and 9B are graphs illustrating an example of the height control of the claw tip 6a. That is, the control in step S123 will be described. Here, the horizontal axis indicates the time. The notation of 901 indicates the operation of the switch NS2. The notation of 902 indicates the amount of operation of the right operation lever 26R in the boom lowering direction. The notation of 910 indicates the pilot pressure supplied to the pilot port of the control valve 175 in the boom lowering direction (the right pilot port of the control valve 175R in FIG. 4B). The pilot pressure is controlled by controlling the proportional valve 31BR by the controller 30. The notation of 930 is the height of the claw tip 6a. The notation of 950 is the target height (first height position) at which the claw tip 6a is stopped.

As illustrated in FIGS. 9A and 9B, at time T1, the operator switches the right lever switch (the switch NS2 of the right operation lever 26R) from an unoperated state (OFF) to an operated state (ON). Next, at time T2, the operator performs a boom lowering operation (the right operation lever 26R is tilted to the boom lowering side (front side)). Thus, the controller 30 controls the proportional valve 31 to supply the pilot pressure 910 to the control valve 175. As a result, the height 930 of the claw tip 6a is lowered and approaches the target height (first height position) 950.

When the height 930 of the claw tip 6a approaches the target height (first height position) 950, the controller 30 controls the proportional valve 31 to reduce the pilot pressure 910 supplied to the control valve 175. Then, at time T3, when the height 930 of the claw tip 6a becomes the target height (first height position) 950, the controller 30 controls the proportional valve 31 to set the pilot pressure 910 to zero in the control valve 175. Thus, the height 930 of the claw tip 6a can be set to the target height 950.

Yet Another Example of Operation of the Excavator

Next, yet another example of the work performed by using the excavator 100 will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart illustrating yet another example of the control of the excavator 100 according to the first embodiment. FIGS. 11A to 11E are schematic views illustrating yet another example of the work performed by using the excavator 100. Here, an example will be described in which a vertical surface 801 is formed on the ground by repeating the vertical lowering of the bucket 6 at the same horizontal distance with the claw tip 6a.

The operator operates the operation device 26 (the left operation lever 26L, the right operation lever 26R) to move the claw tip 6a of the bucket 6 to the excavation start position. That is, the claw tip 6a of the bucket 6 is adjusted to a predetermined horizontal distance (first horizontal distance, initial position with respect to the second control mode). For example, the operator first operates the excavator 100 in the regular mode (see S102) to move the position of the claw tip 6a of the bucket 6 to the position illustrated in FIG. 11A.

In step S141, the operator performs a boom lowering operation (the right operation lever 26R is tilted to the boom lowering side (front side)) while pressing the right lever switch (the switch NS2 of the right operation lever 26R).

Here, when the right lever switch is operated and the boom lowering operation is input (YES in S101, NO in S103, YES in S107), the controller 30 controls the attachment AT in the control mode (second control mode, see S109 or S110) to move the claw tip 6a vertically while holding the claw tip 6a at the first horizontal distance. Thus, the bucket 6 is vertically lowered. At this time, when controlling the attachment AT in the second control mode, the controller 30 stores the horizontal distance (first horizontal distance, initial position with respect to the second control mode) of the claw tip 6a at the time of the boom lowering operation in a storage part (not illustrated) of the controller 30. Thus, a vertical surface 801 is formed and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 11B.

In step S142, the operator operates the attachment AT in the regular mode (see S102). Note that the left lever switch (the switch NS1 of the left operation lever 26L) and the right lever switch (the switch NS2 of the right operation lever 26R) are not operated (S101, NO), and the controller 30 controls the attachment AT in the regular control mode (S102). Thus, the claw tip 6a of the bucket 6 is moved to a position before the next excavation position. For example, the operator operates the operation device 26 to perform an arm closing operation to move the claw tip 6a of the bucket 6 away from the vertical surface 801. Then, the operator operates the operation device 26 to perform a boom raising operation to move the claw tip 6a of the bucket 6 to a position before the next excavation position (second horizontal distance). The second horizontal distance is a position away from the first horizontal distance (a position away from the vertical surface 801). Thus, the position of the claw tip 6a of the bucket 6 is moved to a position illustrated in FIG. 11C.

In step S142, the attachment AT is operated to move the claw tip 6a of the bucket 6 to a position before the next excavation position, but this is not limited. For example, in the case of forming the vertical surface 801 having a cylindrical surface when viewed from above, hydraulic oil may be supplied to the turning hydraulic motor 2A to turn the upper turning body 3. When a long vertical surface 801 is formed, the upper turning body 3 faces the direction of the vertical surface 801 while the lower traveling body 1 faces the direction parallel to the vertical surface 801, and hydraulic oil may be supplied to the travel hydraulic motors 2ML and 2MR to cause the excavator 100 (the lower traveling body 1) to travel.

Even if the lower traveling body 1 of the excavator 100 travels or turns, the controller 30 retains the stored horizontal distance (first horizontal distance, initial position with respect to the second control mode) of the claw tip 6a in the storage part without being reset. Even if the upper turning body 3 of the excavator 100 turns, the controller 30 retains the stored horizontal distance (first horizontal distance, initial position with respect to the second control mode) of the claw tip 6a in the storage part without being reset.

In step S143, the operator performs an arm opening operation (the left operation lever 26L is tilted to the arm opening side (rear side)) while pressing the left lever switch (the switch NS1 of the left operation lever 26L). Here, the controller 30 controls the attachment AT in a control mode (fifth control mode) for moving the claw tip 6a until the first horizontal distance stored in step S141 is reached. When the claw tip 6a reaches the first horizontal distance, even if the arm opening operation is performed while continuously pressing the left lever switch, the horizontal distance of the claw tip 6a remains at the first horizontal distance and does not advance beyond that horizontal distance.

Here, when the arm opening operation is input while pressing the left lever switch, the controller 30 controls the attachment AT in a regular control mode (see S102) for opening the arm 5. Further, the controller 30 detects the horizontal distance of the claw tip 6a based on, for example, a sensor (the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3) for detecting the posture of the attachment AT. The controller 30 opens the arm 5 by the arm opening operation until the detected horizontal distance of the claw tip 6a becomes the first horizontal distance stored in step S141. On the other hand, when the detected horizontal distance of the claw tip 6a becomes the first horizontal distance stored in step S141, the controller 30 performs control such that the arm 5 does not open further even if the arm opening operation is performed. Thus, the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 11D.

Alternatively, when the arm opening operation is input while pressing the left lever switch, the controller 30 controls the attachment AT in a control mode (see S105 or S106) to move the claw tip 6a horizontally. Further, the controller 30 detects the horizontal distance of the claw tip 6a based on, for example, a sensor (the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3) that detects the posture of the attachment AT. Until the detected horizontal distance of the claw tip 6a becomes the first horizontal distance stored in step S141, the controller 30 moves the claw tip 6a horizontally inward by the arm opening operation. On the other hand, when the detected horizontal distance of the claw tip 6a becomes the first horizontal distance stored in step S141, the controller 30 controls the claw tip 6a to not move further horizontally inward even if the arm opening operation is performed. Thus, the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 11D.

In step S143, the excavator 100 may include a switch (an example of the input device D2) that switches between a regular control mode in which the arm 5 is opened and a control mode in which the claw tip 6a is moved horizontally. This switch (an example of the input device D2) may be a touch panel mounted on the display of the display device for displaying various information images, a knob switch provided at the tip of the lever part of the operation device 26, a button switch, a lever, a toggle, a rotary dial, or the like installed around the display device D1. Further, the selection result of the switch may be displayed on the display device D1.

In step S144, the operator performs a boom lowering operation (the right operation lever 26R is tilted to the boom lowering side (front side)) while pressing the right lever switch (the switch NS2 of the right operation lever 26R).

Here, when the right lever switch is operated and the boom lowering operation is input (YES in S101, YES in S103), the controller 30 controls the attachment AT in a control mode (second control mode, see S109 or S110) in which the claw tip 6a is held at the first horizontal distance and moved vertically. Thus, the bucket 6 is vertically lowered. At this time, the controller 30 stores the horizontal distance (first horizontal distance, initial position with respect to the second control mode) of the claw tip 6a at the time of the boom lowering operation in a storage part (not illustrated) of the controller 30. Thus, the vertical surface 801 is formed, and the position of the claw tip 6a of the bucket 6 is moved to the position illustrated in FIG. 11E.

When the vertical lowering of the bucket 6 is further repeated, the processing of steps S142 to S144 is repeated.

Thus, in steps S141 and S144, the vertical lowering of the bucket 6 can be performed with the same horizontal distance (first horizontal distance, initial position with respect to the second control mode) of the claw tip 6a. That is, when the horizontal distance of the claw tip 6a is adjusted before starting the second vertical lowering of the bucket 6 (S144), the horizontal distance can be easily adjusted to match the horizontal distance of the claw tip 6a in the first vertical lowering of the bucket 6 (S141).

By repeating the vertical lowering of the bucket 6 at the same position, the surface accuracy of the vertical surface 801 can be improved.

Further, by accompanying the turning of the upper turning body 3 and/or the movement of the excavator 100 in step S142, a wide vertical surface 801 can be formed. For example, in step S142, the upper turning body 3 faces the direction of the vertical surface 801 and the lower traveling body 1 faces the direction parallel to the vertical surface 801, such that by moving the excavator 100, a laterally long wall surface (the vertical surface 801) can be formed.

Further, in the example of FIGS. 11A to 11E, the case where the excavation of the vertical surface 801 is repeated has been described as an example, but it may be applied to the excavation of the vertical surface 803 (see FIGS. 5(d) to 5(e)).

In step S143, the controller 30 has been described as controlling the attachment AT in a fifth control mode for moving the claw tip 6a to the stored first horizontal distance when a predetermined second operation (while pressing the left lever switch, open the arm) is input, but this is not limited to this. The predetermined second operation may be input of a predetermined switch or input of a predetermined voice to an audio input part (not illustrated) provided in the cabin 10. The fifth control mode may be configured to automatically move the claw tip 6a to the stored first horizontal distance when a predetermined second operation is input.

The excavator 100 may include a switch (an example of the input device D2) for resetting the stored horizontal distance (the first horizontal distance) of the claw tip 6a. The switch (an example of the input device D2) may be any of a touch panel mounted on the display of a display device for displaying various information images, a knob switch provided at the tip of the lever part of the operation device 26, a button switch, a lever, a toggle, a rotary dial, or the like installed around the display device D1. Further, the result of the selection of the switch may be displayed on the display device D1.

When the right lever switch is operated and the boom lowering operation is input while the claw tip 6a is positioned at another horizontal distance (new excavation start position) (see S141), the controller 30 overwrites and stores the horizontal distance (first horizontal distance, initial position with respect to the second control mode) of the claw tip 6a at the time of the boom lowering operation, in the storage part (not illustrated) of the controller 30.

Second Embodiment

Next, an example of work performed by using the excavator 100 according to the second embodiment will be described with reference to FIGS. 12A and 12B. FIGS. 12A and 12B are schematic views illustrating an example of work performed by using the excavator 100 according to the second embodiment. Here, the work of lifting a suspended load 900 by a hook 6c and moving the suspended load 900 horizontally or vertically will be described as an example.

The hook 6c for crane work is attached to the bucket 6 so as to be able to be stored and to be able to turn. Here, the excavator 100 lifts the suspended load 900 by the hook 6c.

FIG. 12A illustrates an example of work of lifting the suspended load 900 by the hook 6c and moving the suspended load 900 horizontally.

FIG. 12B illustrates an example of work of lifting the suspended load 900 by the hook 6c and moving the suspended load 900 vertically.

A configuration in which the suspended load 900 is lifted by the hook 6c as the lifting position will be described as an example, but this is not limited. A configuration in which the suspended load 900 is lifted by a connecting pin (an arm top pin) connecting the arm 5 and the bucket 6 as the lifting position may be used. A configuration in which the suspended load 900 is lifted by the hook provided on the end attachment as the lifting position may be used. A configuration in which the suspended load 900 is lifted by the hook provided at a link connecting the rod side of the bucket cylinder 9, the arm 5, and the bucket 6 (end attachment) as the lifting position may be used. The operation for making the excavator 100 move the suspended load 900 in the horizontal and/or the vertical direction is a combined operation in which the boom 4, the arm 5, and the like are operated simultaneously, and the skill of the operator is required. In the case of an operator who is not skilled in the operation, there is a possibility that the suspended load 900 may collide with the ground or other objects because the horizontal and vertical movement cannot be performed as intended by the operator.

Another Example of Operation of the Excavator

Next, an example of the control of the excavator 100 according to the second embodiment will be described with reference to FIG. 13. FIG. 13 is a flowchart illustrating an example of the control of the excavator 100 according to the second embodiment.

In step S201, the controller 30 determines whether or not the switches NS1 and NS2 are operated. Here, the switches NS1 and NS2 are switches for selecting whether or not to enable the machine control function. The switches NS1 and NS2 may be momentary switches that turn ON only while the switches NS1 and NS2 are pressed and turn OFF when the switches NS1 and NS2 are released. The switches NS1 and NS2 may be alternate switches that switch ON and OFF each time the switches NS1 and NS2 are pressed. The switches NS1 and NS2 may be operated by operating either switch or both switches.

When the switches NS1 and NS2 are not operated (NO in S201), that is, when the switches NS1 and NS2 are in the OFF state, the controller 30 proceeds to step S202.

In step S202, the controller 30 determines that regular control is to be performed. That is, when the operator operates the operation device 26, the controller 30 controls the attachment AT in the regular control mode (refer to the operation directions of the left operation lever 26L and the right operation lever 26R and the operation of the attachment AT illustrated in FIG. 3). Specifically, when the operator operates the left operation lever 26L in the longitudinal direction, the controller 30 controls the control valve 176 which supplies hydraulic oil to the arm cylinder 8 via the proportional valves 31AL and 31AR. Thus, the arm 5 of the attachment AT operates (opens and closes). Further, when the operator operates the right operation lever 26R in the longitudinal direction, the controller 30 controls the control valve 175 which supplies hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR. Thus, the boom 4 of the attachment AT operates (up and down).

On the other hand, when the switches NS1 and NS2 are operated (YES in step S201), that is, when the switches NS1 and NS2 are in the ON state, the controller 30 proceeds to step S203.

In step S203, the controller 30 determines whether one of the operation levers is operated. Here, the controller 30 determines whether the left operation lever 26L is operated in the front or back direction (the open or closed direction of the arm 5). If one of the operation levers is not operated (NO in step S203), the controller 30 proceeds to step S205.

If one of the operation levers is operated (YES in step S203), the controller 30 proceeds to step S204. Here, as illustrated in step S204, which will be described later, the controller 30 controls the attachment AT in the first control mode in which the reference position of the attachment AT is horizontally moved by the longitudinal operation of the left operation lever 26L. Here, the reference position may be any of the hook 6c supporting the suspended load, the rotating shaft of the hook 6c (the pin connecting the arm 5 and the bucket 6), or the like. By horizontally moving the reference position, the suspended load 900 is also horizontally moved. That is, the controller 30 controls the operation of the arm 5 based on the amount of operation of the left operation lever 26L in the longitudinal direction. In accordance with the operation of the arm 5, the controller 30 automatically controls the operation of the boom 4 so as to move the reference position horizontally.

In step S204, the controller 30 controls the attachment AT in the control mode so as to move the reference position of the attachment AT horizontally. Specifically, when the operator operates the left operation lever 26L in the longitudinal direction, the controller 30 controls the control valve 176 which supplies hydraulic oil to the arm cylinder 8, via the proportional valves 31AL and 31AR. Thus, the arm 5 of the attachment AT operates (opens and closes). Further, the controller 30 automatically controls the control valve 175 which supplies hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR so as to move the reference position of the attachment AT horizontally. Here, the opening/closing angle of the bucket 6 relative to the arm 5 is maintained.

If one of the operation levers is not operated (NO in step S203), the controller 30 proceeds to step S205.

In step S205, the controller 30 determines whether the other operation lever is operated. Here, the controller 30 determines whether the right operation lever 26R is operated in the front or back direction (the downward direction or the upward direction of the boom 4). If the other operation lever is not operated (NO in step S205), the controller 30 returns to step S203.

If the other operation lever is operated (YES in step S205), the controller 30 proceeds to step S206. Here, as illustrated in step S206, which will be described later, the controller 30 controls the attachment AT in a second control mode in which the reference position of the attachment AT is vertically moved by the longitudinal operation of the right operation lever 26R. Here, the reference position may be any one of the hook 6c supporting the suspended load, the rotating shaft of the hook 6c (the pin connecting the arm 5 and the bucket 6), etc. By vertically moving the reference position, the suspended load 900 also moves vertically.

In step S206, the controller 30 controls the attachment AT in the control mode of vertically moving the reference position of the attachment AT. Specifically, the controller 30 controls the control valve 175 supplying hydraulic oil to the boom cylinder 7, via the proportional valves 31BL and 31BR when the operator operates the right operation lever 26R in the longitudinal direction. As a result, the boom 4 of the attachment AT operates (opens and closes). Also, the controller 30 automatically controls the control valve 176 supplying hydraulic oil to the arm cylinder 8, via the proportional valves 31AL and 31AR so as to vertically move the reference position of the attachment AT. Here, the opening and closing angle of the bucket 6 with respect to the arm 5 is maintained. That is, the controller 30 controls the operation of the boom 4 based on the amount of operation of the right operation lever 26R in the longitudinal direction. In accordance with the operation of the boom 4, the controller 30 automatically controls the operation of the boom 4 so as to vertically move the reference position.

As described above, according to the excavator 100 according to the second embodiment, even an operator who is not skilled in operating the excavator 100 can easily convey the suspended load 900 in the horizontal and vertical directions.

Third Embodiment

In the third embodiment, a case where an operator remotely operates the excavator 100 will be described.

FIG. 14 is a schematic diagram illustrating a configuration example of a remote support system SYS of the excavator 100 according to the third embodiment. In the example illustrated in FIG. 14, the excavator 100 and the remote operation room RC are connected via the communication network NW. Thus, information can be transmitted and received between the excavator 100 and the remote operation room RC.

The excavator 100 transmits detection results from various sensors provided in the excavator 100 to the remote operation room RC by using the communication device T1 provided in the excavator 100. For example, the excavator 100 transmits image information captured by the imaging device S6, the turning angle, and the detection results of various sensors to the remote operation room RC.

In the remote support system SYS according to the third embodiment, a remote operation room RC is provided. The remote operation room RC is provided with a display device DR, an operation device R26, an operation sensor R29, an operation seat DS, a remote controller R30, and a communication device T2. The operation device R26 is provided with a switch NS3. The switch NS3 may be provided on the left and right operation levers as in the case of the excavator 100 according to the first and second embodiments.

The remote controller R30 displays, on the display device DR, a display screen based on the image information captured by the imaging device S6, the turning angle, and the detection results of various sensors. Thus, the operator OP present on the operation seat DS can check the surrounding situation of the excavator 100, even when present in the remote operation room RC.

The operator OP on the operation seat DS of the remote operation room RC operates the operation device R26. The operation sensor R29 detects the operation contents received by the operation device R26. The controller 30 generates a control signal corresponding to the operation contents. The communication device T2 transmits the generated control signal to the excavator 100. The remote controller R30 transmits the control signal to enable remote operation of the excavator 100.

Further, by operating the operation device R26 while the switch NS3 is operated, the position of the claw tip 6a of the bucket 6 can be moved vertically or horizontally in the same manner as the excavator 100 according to the first and second embodiments.

Thus, the remote support system SYS of the excavator 100 according to the third embodiment can be controlled (see FIGS. 6, 7, 10, 13) in the same manner as the excavator 100 according to the 1 to 2 embodiment. Thus, even in the excavator 100 according to the third embodiment, it is possible to easily perform the work of moving the reference position of the attachment AT in the horizontal direction or the vertical direction. Moreover, the height position and the horizontal distance of the claw tip 6a of the bucket 6 can be easily adjusted.

The excavator 100 (work machine) according to the first to third embodiments has been described as an example of a configuration having the bucket 6 as an end attachment, but the present invention is not limited thereto. The end attachment may be any of a crusher for grasping and crushing an object, a breaker for striking and crushing an object, a grapple for grasping an object, a tilt bucket which is a bucket to which a tilt mechanism is added, a compactor for compacting with soil, a bucket thumb which is a bucket capable of grasping an object, an auger for piling, and a tilt rotator which is a bucket to which a tilt mechanism and a rotation mechanism are added.

Note that the crusher, breaker, grapple, and auger may be configured so as to be easily moved in the horizontal and/or vertical direction by, for example, the control illustrated in FIG. 13.

Further, the bucket 6, the tilt bucket, the compactor, the bucket thumb, and the tilt rotator may be configured to be easily moved in the horizontal and/or vertical direction by the control illustrated in FIG. 6, for example, and may be configured to be moved in the horizontal and/or vertical direction while maintaining the angle (for example, the angle of the bottom surface 6b of the bucket 6) of the end attachment. It is preferable to apply this control to the tilt bucket after setting the tilt angle to 0°. For the tilt rotator, it is preferable to apply the control after setting the tilt angle to 0° and the rotation angle to 0°.

The switches NS1 and NS2 are provided in each of the left operation lever 26L and the right operation lever 26R, but the switch is not limited to this, and only one of the operation levers may be provided with the switch.

The embodiments of the excavator according to the present invention have been described above, but the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These are also naturally within the scope of the present invention.

According to the above embodiment, it is possible to provide a work machine which improves work efficiency.

Claims

1. A work machine comprising: a lower traveling body;an upper turning body configured to turn with respect to the lower traveling body;an attachment attached to the upper turning body and including at least a boom or an arm;an operation device including one operation lever and another operation lever; anda control part, whereinthe control part controls the attachment in a first control mode when the one operation lever is operated, andthe control part controls the attachment in a second control mode when the other operation lever is operated.

2. The work machine according to claim 1, wherein the one operation lever is configured to operate the arm,the other operation lever is configured to operate the boom,in the first control mode, when the one operation lever is operated to operate the arm, the boom is automatically operated, andin the second control mode, when the other operation lever is operated to operate the boom, the arm is automatically operated.

3. The work machine according to claim 2, wherein in the first control mode, when the one operation lever is operated, a reference position of the attachment is moved in a horizontal direction, andin the second control mode, when the other operation lever is operated, the reference position of the attachment is moved in a vertical direction.

4. The work machine according to claim 3, wherein the attachment further includes a bucket, andthe reference position is a position of a claw tip of the bucket.

5. The work machine according to claim 4, wherein in the first control mode, in a case where an angle between the horizontal direction and a bottom surface of the bucket is within a predetermined first range, when the one operation lever is operated, the angle of the bottom surface of the bucket with respect to the horizontal direction is maintained and the reference position of the attachment is moved in the horizontal direction, andin the second control mode, in a case where an angle between the vertical direction and the bottom surface of the bucket is within a predetermined second range, when the other operation lever is operated, the angle of the bottom surface of the bucket with respect to the vertical direction is maintained and the reference position of the attachment is moved in the vertical direction.

6. The work machine according to claim 3, wherein the reference position is a suspending position for suspending a suspended load.

7. The work machine according to claim 1, wherein the operation device further includes a switch,the control part controls the attachment in the first control mode when the switch is operated and the one operation lever is operated, andthe control part controls the attachment in the second control mode when the switch is operated and the other operation lever is operated.

8. The work machine according to claim 7, wherein the switch includes: a first switch provided on the one operation lever; anda second switch provided on the other operation lever,the control part controls the attachment in the first control mode when the first switch is operated and the one operation lever is operated, andthe control part controls the attachment in the second control mode when the second switch is operated and the other operation lever is operated.

9. The work machine according to claim 1, wherein the operation device further includes a switch,the control part controls the attachment in the first control mode when the switch is operated and the one operation lever is operated in a first direction,the control part controls the attachment in the second control mode when the switch is operated and the other operation lever is operated, andthe control part controls the attachment in a third control mode when the switch is operated and the one operation lever is operated in a second direction orthogonal to the first direction.

10. The work machine according to claim 9, wherein in the third control mode, the reference position of the attachment is moved in a transverse direction when the one control lever is operated in the second direction.

11. The work machine according to claim 1, wherein the control part stores at least one of an initial position for the first control mode or an initial position for the second control mode.

12. The work machine according to claim 11, wherein the control part is configured to execute: a fourth control mode of controlling the attachment to move to the initial position with respect to the first control mode based on a predetermined first operation; anda fifth control mode of controlling the attachment to move to the initial position with respect to the second control mode based on a predetermined second operation.

13. The work machine according to claim 11, wherein the control part stores the initial position with respect to the first control mode when controlling the attachment in the first control mode, andthe control part stores the initial position with respect to the second control mode when controlling the attachment in the second control mode.

14. The work machine according to claim 11, wherein the control part does not reset at least one of the initial position with respect to the first control mode or the initial position with respect to the second control mode even when the lower traveling body travels.

15. A remote support system that remotely operates a work machine, the remote support system comprising: the work machine including: a lower traveling body;an upper turning body configured to turn with respect to the lower traveling body; andan attachment attached to the upper turning body and including at least a boom or an arm;a remote operation room including an operation device including one operation lever and another operation lever; anda control part; whereinthe control part controls the attachment in a first control mode when the one operation lever is operated, andthe control part controls the attachment in a second control mode when the other operation lever is operated.