Patent Application
20130087355
The invention relates to an impact tool.
Japanese Patent Application Publication No. 2010-264534 provides an impact driver that performs a fastening work by rotating a hammer in only forward direction. The impact driver can provide a strong fastening force although noise during fastening work is loud.
On the other hands, Japanese Patent Application Publication No. 2011-62771 provides an electronic pulse driver that performs a fastening work by rotating a hammer in both forward direction and reverse direction. The electronic pulse driver can provide a fastening force with a small noise although the fastening force is small compared with the impact driver.
It is an object of the invention to provide an impact tool capable of selectively serving as an impact driver or an electronic pulse driver.
In order to attain the above and other objects, the invention provides an impact tool including a motor; a hammer having a rotational axis extending in a first direction, the hammer being rotatable in a rotational direction including a forward direction and a reverse direction opposite to the forward direction by the motor and being movable in the first direction and a second direction opposite to the first direction; an anvil disposed at the first direction side of the hammer and strikable by the hammer in the forward direction, the hammer that has been struck the anvil being moved in the second direction to come free from the anvil; and a fixing member that selectively allows the hammer to move in the second direction or prevents the hammer from moving in the second direction.
With this construction, a user can selectively use the impact tool as the impact driver or the electronic pulse driver.
Preferably, the impact tool further includes a controller configured to control the motor so that the hammer is sequentially rotated, when the fixing member allows the hammer to move in the second direction, and so that the hammer is intermittently rotated, when the fixing member prevents the hammer from moving in the second direction.
With this construction, the impact tool can operate at an impact mode when the fixing member allows the hammer to move in the second direction, and can operate at an electronic pulse mode when the fixing member prevents the hammer from moving in the second direction.
Preferably, the impact tool further includes an operating member for instructing the fixing member to allow the hammer to move in the second direction or prevent the hammer from moving in the second direction.
Preferably, the impact tool further includes a case covering the operating member and formed with a groove having a first groove and a first groove, wherein the operating member protrudes from the groove, the hammer being allowed to move in the second direction when the fixing member protrudes from the first groove, and being prevented from moving in the second direction when the fixing member protrudes from the first groove.
Preferably, the first groove and the second groove are connected with one another, the first groove extending in the first direction, the second groove extending in the rotational direction.
With this construction, the mode is prevented from being switched due to the vibration of the impact tool.
Preferably, the impact tool further includes a plurality of operating units, wherein the case is formed with a plurality of grooves, the plurality of operating members protruding from the plurality of grooves, respectively.
Preferably, the impact tool further includes a receiving member that receives the hammer moving in the second direction and having a first protrusion protruding in the second direction; and a contacting member disposed at the second direction side of the receiving member and having a second protrusion protruding in the first direction, wherein the hammer is prevented from moving in the second direction when the first protrusion is opposed to the second protrusion in the first direction.
Preferably, the impact tool further includes a receiving member that receives the hammer moving in the second direction; and a low frictional member disposed between the hammer and the receiving member.
With this construction, it becomes possible to suppress the occurrence of the rotational friction between the hammer and the receiving member when the hammer is moved in the second direction.
Preferably, the impact tool further includes a supporting member that loosely supports the low friction member with respect to the receiving member in the second direction.
With this construction, it becomes possible to suppress the occurrence of the rotational friction between the supporting member and the low friction member when the hammer is moved in the second direction.
Another aspect of the present invention provides an impact tool including a motor; a hammer having a rotational axis extending in a first direction, the hammer being rotatable in a rotational direction including a forward direction and a reverse direction opposite to the forward direction by the motor and being movable in the first direction and a second direction opposite to the first direction; an anvil disposed at the first direction side of the hammer and strikable by the hammer in the forward direction, the hammer that has struck the anvil being movable in the second direction to come free from the anvil; and a controller configured to rotate the motor in the forward direction at a power such that the hammer that has struck the anvil is prevented from riding over the anvil, and rotates the motor in the reverse direction after the hammer has struck the anvil.
With this construction, the impact tool can achieve the electronic pulse mode with a simple construction although the hammer is not fixed in the second direction.
Preferably, the impact tool further includes a setting unit in which one of a first mode and a second mode is settable as an operation mode of the hammer, wherein when the first mode is set, the controller rotates the motor in the forward direction at a power such that the hammer that has struck the anvil moves in the second direction to ride over the anvil, and wherein when the second mode is set, the controller rotates the motor in the forward direction such that the hammer that has struck the anvil is prevented from riding over the anvil, and rotates in the reverse direction after the hammer has struck the anvil.
With this construction, a user can selectively use the impact tool as the impact driver or the electronic pulse driver.
Preferably, a third mode is further settable in the setting unit, wherein when the third mode is set, before a load applied to the motor increases to a predetermined value, the controller controls the motor at the second mode, and after a load applied to the motor increases to the predetermined value, the controller controls the motor at the first mode.
With this construction, a user can use the impact tool as the electronic pulse driver that provide a fastening force with a small noise although the fastening force is small compared with the impact driver firstly, and can use the impact tool as the impact driver that provides a stronger fastening force than the electronic pulse driver after a load applied to the motor increases to a predetermined value.
Preferably, a fourth mode is further settable in the setting unit, wherein when the fourth mode is set, the controller keeps rotating the motor in the forward direction at a power such that the hammer that has struck the anvil is prevented from riding over the anvil direction.
With this construction, the impact tool can operate at the drill mode.
An impact tool of the present invention can selectively serve as an impact driver or an electronic pulse driver.
Hereinafter, the configuration of an impact tool 1 according to a first embodiment of the invention will be described while referring to
As shown in
The motor 3 is disposed within the body section 21 so that the axial direction of the motor 3 matches the lengthwise direction of the body section 21. Within the body section 21, the hammer section 4 and the anvil section 5 are arranged toward one end side of the motor 3 in the axial direction. In descriptions provided below, the anvil section 5 side is defined as a front side, the motor 3 side is defined as a rear side, and a direction parallel to the axial direction of the motor 3 is defined as a front-rear direction. Additionally, the body section 21 side is defined as an upper side, the handle section 22 side is defined as a lower side, and a direction in which the handle section 22 extends from the body section 21 is defined as an upper-lower direction. Further, a direction perpendicular to both the front-rear direction and the upper-lower direction is defined as a left-right direction.
As shown in
A light 2A is provided at a position adjacent to the opening 23a and below the hammer case 23 for irradiating a bit mounted on an end-bit mounting section 51 described later. The light 2A is provided to illuminate forward during work at dark places and to light up a work location. The light 2A is lighted normally by turning on a switch 2B described later, and goes out by turning off the switch 2B. The light 2A also has a function of blinking when temperature of the motor 3 rises to inform an operator of the temperature rising, in addition to the original function of illumination of the light 2A.
The handle section 22 extends downward from a substantially center position of the body section 21 in the front-rear direction, and is formed as an integral part with the body section 21. A trigger 25 and a forward-reverse switching lever 2C for switching rotational direction of the motor 3 are provided at an upper section of the handle section 22. The switch 2B and a dial 27 are provided at a lower section of the handle section 22. The switch 2B is for switching on and off of the light 2A, and the dial 27 is for switching a plurality of modes in an electronic pulse mode described later by a rotating operation. A battery 24, which is a rechargeable battery that can be charged repeatedly, is detachably mounted at a lower end section of the handle section 22 in order to supply the motor 3 and the like with electric power. The board 26 is disposed at a lower position within the handle section 22. A switch mechanism 22A is built in the handle section 22 for transmitting an operation of the trigger 25 to the board 26.
The board 26 is supported within the handle section 22 by a rib (not shown). The control section 7, a gyro sensor 26A, an LED 26B, a support protrusion 26C, and a dial-position detecting element 26D (
Here, the structure of the dial 27 and the dial supporting section 28 will be described while referring to
As shown in
As shown in
The engaging section 27B, the engaging claws 27C, and the protrusions 27D of the dial 27 are inserted into the engaged hole 28b from the upper side, and also the support protrusion 26C on the board 26 is inserted into the engaged hole 28b from the lower side, thereby allowing the dial 27 to be rotatable about the support protrusion 26C. Further, the guiding protrusions 28C of the dial supporting section 28 are arranged in a circumferential shape so as to fit the inner circumference of the concave and convex sections 27A of the dial 27, and the engaging claws 27C and the protrusions 27D of the dial 27 are also arranged in a circumferential shape so as to fit the engaged hole 28b of the dial supporting section 28, which enables smooth rotation of the dial 27. Additionally, the engaged hole 28b is provided with a step (not shown) so that the engaging claws 27C inserted in the engaged hole 28b engage the step, thereby restricting movement of the dial 27 in the upper-lower direction.
The ball 28A is urged upward by the spring 28B inserted in the spring inserting hole 28a. Hence, by rotating the dial 27, a portion of the ball 28A is buried in one of the through holes 27a. Because each though hole 27a corresponds to one of a plurality of modes in an electronic pulse mode to be described later, the operator can recognize that the mode has changed, from feeling or the like that a portion of the ball 28A is buried in the through hole 27a. On the other hand, the LED 26B on the board 26 is inserted in the LED receiving hole 28c. Hence, when a portion of the ball 28A is buried in the through hole 27a, the LED 26B can irradiate onto the dial seal 29 from the lower side through the through hole 27a located at a 180-degree opposite position on the dial 27 with respect to the engaging hole 27b from the through hole 27a in which the portion of the ball 28A is buried.
Further, a dial seal 29 shown in
Referring to
The output shaft 31 protrudes at the front and the rear of the rotor 3A, and is rotatably supported by the body section 21 via bearings at the protruding sections. A fan 32 is provided at the protruding section of the output shaft 31 at the front side, so that the fan 32 rotates coaxially and together with the output shaft 31. A pinion gear 31A is provided at the front end position of the protruding section of the output shaft 31 at the front side, so that the pinion gear 31A rotates coaxially and together with the output shaft 31.
The circuit board 33 for mounting thereon electric elements is disposed at the rear of the motor 3. As shown in
The rotational-position detecting elements 33A are for detecting the position of the rotor 3A. The rotational-position detecting elements 33A are provided at positions in confrontation with the permanent magnet 3C of the rotor 3A, and are arranged at a predetermined interval (for example, an interval of 60 degrees) in the circumferential direction of the rotor 3A. The thermistor 33B is for detecting ambient temperature. As shown in
As shown in
The two planetary gears 41B are arranged to meshingly engage the pinion gear 31A around the pinion gear 31A serving as the sun gear and to meshingly engage the outer gear 41A within the outer gear 41A. The two planetary gears 41B are connected to the spindle 41C having the sun gear. With such configuration, rotation of the pinion gear 31A causes the two planetary gears 41B to orbit the pinion gear 31A, and rotation decelerated by the orbital motion is transmitted to the spindle 41C.
The hammer 42 is disposed at the front side of the gear mechanism 41. The hammer 42 is rotatable and movable in the front-rear direction together with the spindle 41C. As shown in
As shown in
The first ring-shaped member 45 has substantially a ring shape, and has a plurality of trapezoidal first convex sections 45A and a protruding section 45B. The plurality of first convex sections 45A protrudes rearward and is arranged at four positions with intervals of 90 degrees in the circumferential direction. The protruding section 45B protrudes downward and, as shown in
The second ring-shaped member 46 has substantially a ring shape, and has a plurality of trapezoidal second convex sections 46A and the operating section 46B. The plurality of second convex sections 46A protrudes frontward and is arranged at four positions with intervals of 90 degrees in the circumferential direction. The operating section 46B protrude upward and, as shown in
When the operating section 46B is not operated, the first convex sections 45A and the second convex sections 46A are located at positions shifted from each other in the circumferential direction, as viewed from the rotational axis direction (the front-rear direction). In this case, since the regulating spring 44 is in a most expanded state as shown in
On the other hand, if the operating section 46B is operated, the second ring-shaped member 46 rotates, and the first convex sections 45A ride on the second convex sections 46A, thereby causing the first ring-shaped member 45 to move forward against the urging force of the regulating spring 44. Hence, since the regulating spring 44 is in a most contracted state, the hammer 42 cannot move rearward. Note that when the operating section 46B is operated, the protruding section 45B and the switch 23A are in contact with each other due to contraction of the regulating spring 44, as shown in
Referring to
The anvil 52 is located at the rear of the end-bit mounting section 51 within the hammer case 23, and is formed as an integral part with the end-bit mounting section 51. The anvil 52 has a first engaged protrusion 52A and a second engaged protrusion 52B that are arranged at opposite positions with respect to the rotational center of the end-bit mounting section 51 and that protrude rearward. When the hammer 42 rotates, the first engaging protrusion 42A and the first engaged protrusion 52A collide with each other and, at the same time, the second engaging protrusion 42B and the second engaged protrusion 52B collide with each other, and the hammer 42 and the anvil 52 rotate together. With this motion, the rotational force of the hammer 42 is transmitted to the anvil 52. The operations of the hammer 42 and the anvil 52 will be described later in greater detail.
The control section 7 mounted on the board 26 is connected to the battery 24, and is also connected to the light 2A, the switch 2B, the forward-reverse switching lever 2C, the switch 23A, the trigger 25, the gyro sensor 26A, the LED 26B, the dial-position detecting element 26D, the dial 27, and the thermistor 33B. The control section 7 includes an electric-current detecting circuit 71, a switch-operation detecting circuit 72, an applied-voltage setting circuit 73, a rotational-direction setting circuit 74, a rotor-position detecting circuit 75, a rotational-speed detecting circuit 76, a striking-impact detecting circuit 77, a calculating section 78, a control-signal outputting circuit 79 (see
Next, the configuration of control system for driving the motor 3 will be described with reference to
Specifically, the energized stator winding U, V, W, that is, the rotational direction of the rotor 3A is controlled by the switching signals H1-H6 inputted to the switching elements Q1-Q6. Further, an amount of power supply to the stator winding U, V, W, that is, the rotational speed of the rotor 3A is controlled by the switching signals H4, H5, and H6 that are inputted to the switching elements Q4-Q6 and also serve as pulse width modulation signals (PWM signals).
The electric-current detecting circuit 71 detects a current value supplied to the motor 3, and outputs the detected current value to the calculating section 78. The switch-operation detecting circuit 72 detects whether the trigger 25 has been operated, and outputs the detection result to the calculating section 78. The applied-voltage setting circuit 73 outputs a signal depending on an operated amount of the trigger 25 to the calculating section 78.
Upon detecting switching of the forward-reverse switching lever 2C, the rotational-direction setting circuit 74 transmits a signal for switching the rotational direction of the motor 3 to the calculating section 78.
The rotor-position detecting circuit 75 detects the rotational position of the rotor 3A based on a signal from the rotational-position detecting elements 33A, and outputs the detection result to the calculating section 78. The rotational-speed detecting circuit 76 detects the rotational speed of the rotor 3A based on a signal from the rotational-position detecting elements 33A, and outputs the detection result to the calculating section 78.
The impact tool 1 is provided with a striking-impact detecting sensor 80 that detects magnitude of an impact that occurs at the anvil 52. The striking-impact detecting circuit 77 outputs a signal from the striking-impact detecting sensor 80 to the calculating section 78.
The calculating section 78 includes a central processing unit (CPU) for outputting driving signals based on processing programs and data, a ROM for storing the processing programs and control data, a RAM for temporarily storing data, and a timer, although these elements are not shown. The calculating section 78 generates the switching signals H1-H6 based on signals from the rotational-direction setting circuit 74, the rotor-position detecting circuit 75 and the rotational-speed detecting circuit 76, and outputs these signals to the inverter circuit 6 via control-signal outputting circuit 79. Further, the calculating section 78 adjusts the switching signals H4-H6 based on a signal from the applied-voltage setting circuit 73, and outputs these signals to the inverter circuit 6 via the control-signal outputting circuit 79. Note that the switching signals H1-H3 may be adjusted as the PWM signals.
Further, ON/OFF signals from the switch 2B and temperature signals from the thermistor 33B are inputted into the calculating section 78. Lighting on, blinking, and lighting off of the light 2A are controlled based on these signals, thereby informing the operator of a temperature increase in the housing 2.
The calculating section 78 switches the operation mode to an electronic pulse mode to be described later, based on an input of a signal generated when the protruding section 45B contacts the switch 23A. Further, the calculating section 78 turns on the LED 26B for a predetermined period, based on an input of a signal generated when the trigger 25 is pulled.
Signals from the gyro sensor 26A are also inputted into the calculating section 78. The calculating section 78 controls the rotational direction of the motor 3 by detecting a velocity of the gyro sensor 26A. The detailed operations will be described later.
Further, signals from the dial-position detecting element 26D that detects a position of the dial 27 in the circumferential direction are inputted into the calculating section 78. The calculating section 78 performs switching of the operation mode based on the signals from the dial-position detecting element 26D.
Next, the usable operation modes and controls of the control section 7 in the impact tool 1 according to the present embodiment will be described. The impact tool 1 according to the present embodiment has two main modes of the impact mode and the electronic pulse mode. The main modes can be switched by operating the operating section 46B to put the switch 23A and the protruding section 45B in contact and out of contact with each other.
The impact mode is a mode in which the motor 3 is rotated only in one direction for causing the hammer 42 to strike the anvil 52. At the impact mode, the operating section 46B is in a state shown in
Specifically, in the impact mode, when the motor 3 rotates, the rotation is transmitted to the hammer 42 via the gear mechanism 41. Thus, the anvil 52 rotates together with the hammer 42. As fastening work proceeds and when the torque of the anvil 52 becomes greater than or equal to the predetermined value, the hammer 42 moves rearward against the urging force of the urging spring 43. At this time, an elastic energy is stored in the urging spring 43. Then, at a moment when the first engaging protrusion 42A rides over the first engaged protrusion 52A and the second engaging protrusion 42B rides over the second engaged protrusion 52B, the elastic energy stored in the urging spring 43 is released, thereby causing the first engaging protrusion 42A to collide with the second engaged protrusion 52B and, at the same time, causing the first engaging protrusion 42A to collide with the first engaged protrusion 52A. With such configuration, the rotational force of the motor 3 is transmitted to the anvil 52 as a striking force. Note that the user can recognize by the positions of the protruding section 45B and the operating section 46B that the impact mode is set. In the present embodiment, if the impact mode is set, the LED 26B is not turned on. Hence, that the user can also recognize by this feature that the impact mode is set.
The electronic pulse mode is a mode in which the rotational speed and the rotational direction (forward or reverse) of the motor 3 is controlled. At the electronic pulse mode, the operating section 46B is in a state shown in
Next, five detailed modes of the electronic pulse mode will be described with reference to
The drill mode is a mode in which the hammer 42 and the anvil 52 keep rotating together in one direction. The drill mode is mainly used when a wood screw is driven and the like. As shown in
As shown in
In the clutch mode, when the trigger 25 is pulled (t1 in
When a fastener is seated on a workpiece, the current value rises sharply (t3 in
Subsequently, the motor 3 is applied with forward-rotation voltage and reverse-rotation voltage for pseudo clutch alternately (t4 in
If the reverse-rotation voltage for pseudo clutch is applied, the hammer 42 separates from the anvil 52. If the forward-rotation voltage for pseudo clutch is applied, the hammer 42 strikes the anvil 52. However, because the forward-rotation voltage and reverse-rotation voltage for pseudo clutch is set to a voltage (for example, 2V) of a degree not applying a fastening force to a fastener, the pseudo clutch is generated merely as striking noise. Due to the generation of the pseudo clutch, the operator can recognize the end of a fastening operation. After the pseudo clutch operates for a period t4, the motor 3 stops automatically (t5 in
As shown in
In the TEKS mode, because importance is not given to fastening with accurate torque, the preliminary start is omitted. First, in a state where the drill 53E of the drill screw 53 is in contact with a steel plate S as shown in
The bolt mode is a mode in which, when a current flowing through the motor 3 increases to a predetermined value (predetermined torque) in a state where the hammer 42 and the anvil 52 are rotated together in one direction, forward rotation and reverse rotation of the motor 3 are switched alternately to fasten a fastener by striking force. The bolt mode is mainly used for fastening a bolt.
In the bolt mode, because importance is not given to fastening with accurate torque, an operation corresponding to the preliminary start in the clutch mode is omitted. In the bolt mode, firstly the motor 3 is rotated only in a forward direction to rotate the hammer 42 and the anvil 52 together in one direction. Then, when the current value of the motor 3 exceeds a threshold value D (t1 in
The pulse mode is a mode in which, when a current flowing through the motor 3 increases to a predetermined value (predetermined torque) in a state where the hammer 42 and the anvil 52 are rotated together in one direction, forward rotation and reverse rotation of the motor 3 are switched alternately to fasten a fastener by striking force. The pulse mode is mainly used for fastening an elongated screw that is used in a place that does not appear outside, and the like. With this mode, a strong fastening force can be provided, and also reaction force from a workpiece can be reduced.
However, because resistance of the fastener increases in a final phase of a fastening operation, the motor 3 outputs a larger torque, which increases reaction that occurs at striking in the impact tool 1. If reaction increases, the handle section 22 is rotatably moved in the opposite direction from the rotational direction of the motor 3 about the output shaft 31 of the motor 3, thereby worsening workability. Hence, in the present embodiment, the gyro sensor 26A built in the handle section 22 detects velocity of the handle section 22 in the circumferential direction about the output shaft 31, that is, magnitude of reaction that is generated in the impact tool 1. If detection velocity by the gyro sensor 26A becomes greater than or equal to a threshold value a described later, the motor 3 is rotated in reverse direction in order to suppress reaction. Note that the gyro sensor 26A is also called as a gyroscope, and is a measurement instrument for measuring angular velocity of an object.
The operation in the pulse mode according to the present embodiment will be described with reference to
In the flowchart of
According to this configuration, because the motor 3 is rotated reversely when the velocity of the gyro sensor 26A exceeds the threshold value a, reaction generated in the impact tool 1 can be suppressed. Further, one can conceive a control method of switching from forward rotation to reverse rotation when the current value of the motor 3 exceeds a predetermined value. In such a control, however, a fastening force becomes weak when the predetermined value is small, whereas large reaction is generated when the predetermined value is large. In contrast, in the present embodiment, when the output of the gyro sensor 26A exceeds the threshold value a, it is determined that an acceptable range of reaction is exceeded, and the motor 3 is rotated reversely. Hence, a maximum fastening force can be obtained within the acceptable range of reaction.
Next, controls of the motor 3 according to the pulled amount of the trigger 25, which are common in all the operation modes in the electronic pulse mode, will be described with reference to
Normally, the trigger 25 is so configured that, as the pulled amount is larger, the duty of PWM signal outputted to the inverter circuit 6 becomes larger. However, if a thin sheet is affixed to a surface layer of a workpiece, there is possibility that the thin sheet is broken at a moment when a fastener is seated on the workpiece. In order to prevent this, the operator changes an electric driver to a manual drive just before a fastener is seated on a workpiece, so that he can fasten the fastener manually, which worsens workability. Thus, in the impact tool 1 of the present embodiment, PWM signal with a constant duty such that the torque of the motor 3 is substantially identical to torque of the fastener is outputted to the inverter circuit 6 when the pulled amount of the trigger 25 is in a predetermined zone, thereby enabling the impact tool 1 to be used to fasten the fastener manually.
When the pulled amount of the trigger 25 is in the first zone, torque of the motor 3 is constant. It is supposed that the torque of the fastener just before the fastener is seated on a workpiece falls into a range between 5-40 N·m. Therefore, in the present embodiment, the torque of the motor 3 is set to the value falling into the above range. When the operator rotates the impact tool 1 about the output shaft 31 with the torque of the motor 3 having the value falling into the above range, the motor 3 rotates with the rotation of the impact tool 1 since the torque of the motor 3 is substantially identical to torque of the fastener. Thus, when the torque of the motor 3 is set to the value falling into the above range, the operator can manually fasten the fastener (
However, when the fastener is fastened to a certain degree, the impact tool 1 is moved to a position where it is difficult to rotate the fastener manually (
According to this configuration, even when a fastener is fastened to a workpiece of which surface layer is affixed with a thin sheet, it is not necessary to change to a manual tool such as a driver when the fastener is seated on the workpiece, and the fastener can be manually fastened only by an operation of the trigger 25, which improves workability. Note that, in the present embodiment, the impact tool 1 can be used like a ratchet wrench by reversely rotating the motor 3 in the second zone. Even if such configuration is not used, the operator may adjust the trigger 25 finely to obtain similar effects.
Next, the configuration of an impact tool 201 according to a second embodiment of the invention will be described while referring to
With such configuration, the operator can fasten a fastener manually simply by turning off the trigger 25.
Next, the configuration of an impact tool 301 according to a third embodiment of the invention will be described while referring to
Next, the configuration of an impact tool 401 according to a fourth embodiment of the invention will be described while referring to
With the configuration in the first embodiment, because the gear mechanism 41 is connected to the housing 2, a reaction force that occurs when the motor 3 rotates the gear mechanism 41 is generated in the impact tool 1 (the housing 2). More specifically, when the spindle 41C is rotated in one direction via the gear mechanism 41, the gear mechanism 41 generates a rotational force opposite to the one direction (reaction force) in the impact tool 1, and this rotational force causes the handle section 22 to rotatably move in the reverse direction about the axial center of the output shaft 31 of the motor 3 (reaction). In particular, in the electronic pulse mode where the hammer 42 and the spindle 41C always rotate together, the above-described reaction becomes more apparent. However, because a gear mechanism is not provided in the fourth embodiment, the above-described reaction force is transmitted softly from the permanent magnet 3C to the housing 2 via the stator 3B. Accordingly, the impact tool 401 is a power tool with less reaction force and good workability. Further, a fastening operation can be done smoothly without reaction force, thereby reducing the number of striking pulses and suppressing power consumption.
As shown in
In the present embodiment, because a gear mechanism (reducer) is not provided, the motor 403 with a low rotational speed is used. In such configuration, however, even if a fan is provided on the output shaft 431 like the first embodiment, a sufficient cooling effect cannot be obtained due to the low rotational speed. Further, in the present embodiment, because a gear mechanism (reducer) is not provided, the motor 403 with a large output torque is used. Hence, the motor 403 of the present embodiment has a larger size than the motor 3 of the first embodiment, and thus requires larger cooling capacity than the first embodiment.
Hence, in the present embodiment, a fan 432 is provided at a lower part of the handle section 22. The fan 432 is controlled to rotate regardless of rotation of the motor 403. Specifically, the fan 432 is connected to the control section 7. The control section 7 controls the fan 432 to rotate when the trigger 25 is pulled, and controls the fan 432 to stop when the trigger 25 is off. Further, in the present embodiment, an air inlet hole 435 is formed at the lower part of the handle section 22, and an air outlet hole 436 is formed at the upper part of the body section 21, so that air flows in a path indicated by the arrow in
Further, a fan switch 402D is provided at the outer frame of the handle section 22. By pressing the fan switch 402D, the fan 432 can be rotated without pulling the trigger 25. Thus, for example, when the operator is informed of a temperature rise of the motor 403 by the light 2A, the motor 403, the board 26, and the circuit board 33 can be cooled forcefully by pressing the fan switch 402D, without pulling the trigger 25.
Next, the configuration of an impact tool 501 according to a fifth embodiment of the invention will be described while referring to
In the present embodiment, a fan 532 is provided at the rear side of the motor 403 within the body section 21. The fan 532 is connected to the control section 7. The control section 7 controls the fan 532 to rotate when the trigger 25 is pulled, and controls the fan 532 to stop when the trigger 25 is off Like
Next, the configuration of an impact tool 601 according to a sixth embodiment of the invention will be described while referring to
In the present embodiment, as shown in
Next, the configuration of an impact tool 701 according to a seventh embodiment of the invention will be described while referring to
As shown in
Further, in the present embodiment, a pair of guide holes 723A is formed at the rear side of a hammer case 723 with intervals of 180 degrees in the circumferential direction. Each of the pair of guide hole 723A has a first guide hole 723a extending in the front-rear direction and a second guide hole 723b extending in the circumferential direction from the front end of the first guide hole 723a.
In the impact mode, the operating section 745B protrudes from the rear end of the first guide hole 723a. On the other hands, the mode is switched to the electronic pulse mode by moving the operating section 745B to the second guide hole 723b, that is, forward direction and then circumferential direction. The operating section 745B cannot move between the first guide hole 723a and the second guide hole 723b without moving the circumferential direction. Therefore, the mode is prevented from being switched due to the vibration of the impact tool 701. Further, since the pair of operating sections 745B protrude from the pair of guide holes 723A respectively, it becomes easy to move the pair of operation sections 745B.
Further, in the present embodiment, washers 747 and 748 and a thrust bearing 749 are disposed between the hammer 42 and the first ring-shaped member 745. The thrust bearing 749 is made of a low frictional material. Therefore, it becomes possible to suppress the occurrence of the rotational friction between the hammer 42 and the first ring-shaped member 745 when the hammer 42 is moved rearward.
Further, as shown in
Note that a resin sheet having a low frictional property such as fluoric resin may be used instead of the thrust bearing 749.
Next, the configuration of an impact tool 801 according to an eighth embodiment of the invention will be described while referring to
In the above embodiments, the electronic pulse mode is achieved by fixing the hammer 42 in the forward-rearward direction. However, in the present embodiment, the electronic pulse mode is achieved by only the control of the motor 3 without fixing the hammer 42 in the forward-rearward direction.
As shown in
When the clutch mode or the impact mode is selected, the impact tool 801 operates in a similar manner as the above embodiments. On the other hands, when the electronic pulse mode is selected, the impact tool 801 operates in a different manner from the above embodiments. The operation of the impact tool 801 when the electronic pulse mode is selected will be described referring to
First, when the trigger 25 is turned on, the control section 7 drives the motor 3 in the forward direction to rotate the anvil 52 together with the hammer 42 (S801 of
Then, when the current flowing into the motor 3 increases to a first current threshold I1 (for example, 5-20 A) smaller than a predetermined value at which the first engaging protrusion 42A (the second engaging protrusion 42B) rides over the first engaged protrusion 52A (the second engaged protrusion 52B) (S802 of
As the fastening work in the electronic pulse mode goes, the current flowing into (torque applied to) the motor 3 increases. If the current increases to the predetermined value, the first engaging protrusion 42A (the second engaging protrusion 42B) will ride over the first engaged protrusion 52A (the second engaged protrusion 52B). Therefore, when the current flowing into the motor 3 increases to a second current threshold I2 slightly smaller than the predetermined value (S804 of
Thus, the impact tool 801 achieves the electronic pulse mode with a simple construction although the hammer 42 is not fixed in the forward-rearward direction.
Further, since the impact tool 801 has a construction same as the conventional impact tool, the increase of the manufacturing cost is suppressed.
Further, the impact tool 801 according to the present embodiment can also operate at a combined mode of the impact mode and the electronic pulse mode. In this case, the impact tool 801 operates at the combined mode when both the first button 82A and the second button 82B are selected. The operation of the impact tool 801 when the combined mode is selected will be described referring to
First, the impact tool 801 operates as S801-S804 of
Thus, the impact tool 801 can operate at the impact mode that gives the fastener a strong fastening power after the torque applied to the motor 3 increases to a predetermined value.
While the invention has been described in detail with reference to the above embodiments thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the claims.
In the above-described embodiment, the gyro sensor 26A is provided on the board 26 to detect reaction that occurs in the handle section 22. However, a position sensor may be provided on the board 26 to detect reaction that occurs in the handle section 22 based on distance by which the handle section 22 is moved. Similarly, an acceleration sensor may be provided instead of the gyro sensor 26A.
However, because an output of the acceleration sensor is not linked directly to a traveling amount of the housing, the acceleration sensor is not suitable for detection of reaction. For example, the acceleration sensor outputs vibrations of the housing and the acceleration sensor itself, which are different from the actual travel of the housing. Accordingly, it is preferable to use a velocity sensor which is effective in indicating the traveling amount of the housing.
In the above-described embodiment, a gyro sensor is used to detect reaction. Alternatively, the traveling amount of the housing may be measured with a GPS, for example. In this case, if the traveling amount of the housing per unit time becomes larger than or equal to a predetermined value, the rotational direction of the motor is changed from the forward rotation to the reverse rotation. Also, an image sensor may be used instead of a GPS.
Alternatively, reaction may be detected by detecting a current instead of using a gyro sensor. However, there is a case in which reaction does not correspond to an output value of the current, and an output value of the gyro sensor always corresponds to reaction. Hence, reaction can be detected more accurately when the gyro sensor is used to detect reaction, than a case in which reaction is detected based on the current. Further, it is conceivable that a torque sensor is provided to the output shaft, instead of the gyro sensor. However, there is also a case in which an output of the torque sensor does not correspond to reaction, and the gyro sensor can detect reaction more accurately.
Although a monochromatic LED is used as the LED 26B in the above-described embodiment, a full color LED may be provided. In that case, the color may be changed depending on a mode set by the dial 27. Further, a color in each mode may be changed by providing color cellophanes at the dial 27. Also, a new informing light may be provided at the body section 21, so that the color of the informing light changes depending on the set mode. Thus, the operator can confirm the set mode at a position closer to his hand.
In the third embodiment, controls are performed so that rotation of the motor 3 is detected to prevent rotation. However, the rotor 3A may be so controlled that the above-described controls are performed only when the rotor 3A is rotated in the direction shown in
In the fourth and fifth embodiments, the fans 432 and 532 stop automatically when the trigger 25 is off. However, if detection temperature of the thermistor 33B is higher than or equal to a predetermined value when the trigger 25 is turned off, the fans 432 and 532 may be driven automatically until the temperature falls below the predetermined value.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-150360 | Jun 2010 | JP | national |
| 2011-100982 | Apr 2011 | JP | national |
| 2011-133408 | Jun 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/065630 | 6/30/2011 | WO | 00 | 11/15/2012 |
