Patent Grant
12030161
This application is the U.S. National Phase under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2020/035458, filed on Sep. 18, 2020, which in turn claims the benefit of Japanese Patent Application No. 2019-186369, filed on Oct. 9, 2019, the entire disclosures of which Applications are incorporated by reference herein.
The present disclosure generally relates to electric tools. The present disclosure specifically relates to an electric tool including an output shaft configured to hold a tip tool and be rotated by motive power provided from an electric motor with the output shaft holding the tip tool.
Patent Literature 1 describes a speed controllable rotary tool configured to control a rotational speed without being provided with a trigger or a switch. The speed controllable rotary tool includes a piezoelectric element disposed at the back of a bit attachment hole in the output shaft. A rear end of a bit fit into the bit attachment hole is pressed against a front surface of the piezoelectric element. As a result, the resistance value of the piezoelectric element changes. The resistance value is detected by a pressing force detector to control the rotational frequency of the motor. In this way, the pressure applied to the bit is adjusted to control the rotational speed of the bit.
In the speed controllable rotary tool described in Patent Literature 1, the rotational speed may increase, that is, the bit (tip tool) may start rotating, immediately in response to generation of force pressing the bit. This may be inconvenient to users.
In view of the foregoing, it is an object of the present disclosure to provide an electric tool with improved convenience.
An electric tool of an aspect of the present disclosure includes an output shaft and a controller. The output shaft is configured to hold a tip tool and be rotated by motive power provided from an electric motor with the output shaft holding the tip tool. The controller is configured to control rotation of the output shaft in accordance with pressing force in a direction from a tip end of the tip tool toward the output shaft. The electric tool has, as an operation range, a restriction range in which the rotation of the output shaft is restricted in a state where the pressing force is less than or equal to a prescribed value.
Note that the drawings to be referred to in the following description of embodiments are all schematic representations. That is to say, the ratio of the dimensions (including thicknesses) of respective constituent elements illustrated on the drawings does not always reflect their actual dimensional ratio.
As shown in
The electric tool 1 according to the present embodiment includes an output shaft 3 (see
In this embodiment, the electric tool 1 has, as an operation range, a restriction range R0 (see
With this configuration, the electric tool 1 has the restriction range R0, and therefore, even when force pressing the tip tool 2 is generated, the possibility that the tip tool 2 immediately starts rotating is reduced. Thus, convenience can be improved.
With reference to
Moreover, in the following description of the electric tool 1, a direction along the X-axis in
As shown in
As shown in
The electric motor 5 is a drive source configured to drive the tip tool 2. The electric motor 5 has a rotary shaft for outputting rotative power. The electric motor 5 is supplied with electric power from the power source 6 to give motive power to the output shaft 3. The electric motor 5 is, for example, a brushless motor. The drive block A1 transmits rotation of the electric motor 5 to the tip tool 2 to drive the tip tool 2.
In this embodiment, the tip tool 2 is a driver bit for tightening (or loosening) the work target 100 but is not particularly limited to this example. The tip tool 2 may be, for example, a drill bit. The work target 100 may be, for example, a screw, a bolt, a vice, or a nut. In
The speed changer 12 includes the output shaft 3, a plurality of gears, and a gear case 120 (see
The output shaft 3 holds the tip tool 2. The output shaft 3 is coupled to the rotary shaft of the electric motor 5 via the plurality of gears. The output shaft 3 is rotated by motive power (driving force) transmitted from the electric motor 5. The output shaft 3 holds the tip tool 2, and in this state, the output shaft 3, together with the tip tool 2, is rotated by the motive power provided from the electric motor 5. The output shaft 3 has a front surface having a bit attachment hole 30 which is recessed rearward. The chuck 7 is fixed to the output shaft 3. Of a plurality of types of tip tools 2, a tip tool 2 suitable for the intended use is fit in the bit attachment hole 30 and is fixed (attached) to the output shaft 3 by the chuck 7. The tip tool 2 may be directly attached to the output shaft 3.
The clutch mechanism E1 is provided in the gear case 120. The clutch handle 14 (dial ring) is located backward of the chuck 7 and is held to be rotatable relative to a body 91 of the housing 9. The clutch handle 14 is coupled to the gear case 120 via the support block 11. A user can rotate the clutch handle 14 by his/her fingers to adjust torque (strength of tightening the work target 100) to any one of a plurality of steps. Detailed description is omitted, but the clutch mechanism E1 includes, for example, a plurality of spheres, a plurality of compression springs for pressing the respective spheres, and a plurality of projections formed in front of the inner gear (ring gear) of the speed changer 12. The support block 11 retracts to increase pressing force with which the compression springs disposed in the gear case 120 press the spheres. When screw tightening torque greater than or equal to a set torque is applied, the plurality of projections in front of the inner gear are caught by the spheres, rotation of the inner gear is thus restricted, and accordingly, the rotation of the output shaft 3 is restricted. As described above, the clutch mechanism E1 is configured to mechanically interrupt a motive power path at a time point at which the screw tightening torque greater than or equal to the set torque is applied with respect to a rotation output of the speed changer 12. This reduces the possibility that the work target 100 is excessively tightened or the work target 100 and the like are crushed.
The power source 6 is a direct-current power supply which is to be used to drive the electric motor 5. The power source 6 includes one or more secondary batteries. The power source 6 is a so-called battery pack and is detachably attached to a rear end (rear end of a grip 92) of the housing 9. The power source 6 is used as an operation power supply for the controller 4, the inverter circuit unit 13, and the like.
The inverter circuit unit 13 is a circuit for driving the electric motor 5. The inverter circuit unit 13 is configured to convert a voltage from the power source 6 into a drive voltage for the electric motor 5. Specifically, the inverter circuit unit 13 includes a Pulse Width Modulation (PWM) inverter and a PWM converter. The PWM converter generates a PWM signal pulse-width-modulated in accordance with a target value of the drive voltage (the U-phase voltage, the V-phase voltage, and the W-phase voltage). The PWM inverter includes half-bridge circuits and drivers for the three phases. In the PWM inverter, the drivers turn on/off switching elements in respective half-bridge circuits in accordance with the PWM signal, thereby applying the drive voltage according to the target value to the electric motor 5. Thus, the electric motor 5 is supplied with a drive current according to the drive voltage. The controller 4 is used along with the inverter circuit unit 13 and performs feedback control to control the operation of the electric motor 5. Note that details of the controller 4 will be described later.
In this embodiment, the electric tool 1 includes a trigger controller TR1 as an operating unit for receiving an operation for controlling rotation of the electric motor 5. Note that the trigger controller TR1 of the present embodiment includes the output shaft 3, the sensing unit 8, and part of the support block 11 (a transfer part 111 and a support 112 which will be described later). The trigger controller TR1 is configured, when receiving pressing force form the tip end of the tip tool 2, to adjust, in accordance with the magnitude of the pressing force, the rotational speed of the output shaft 3, that is, the rotational speed of the electric motor 5. Thus, giving an operation to the trigger controller TR1 controls the rotational speed of the electric motor 5, thereby controlling the rotational speed of the tip tool 2.
The electric tool 1 further includes a motor rotation measuring unit 15 (see
As shown in
The tip end cover 90 is tubular and has a rear surface which is open. The tip end cover 90 is detachably attached to the body 91 to cover the entirety of the clutch handle 14. Moreover, the tip end cover 90 has a front surface having an insertion hole 93 communicated to an internal space, and in a state where the tip end cover 90 is attached to the body 91, a tip end of the output shaft 3 and the chuck 7 protrude to an outer side through the insertion hole 93. The tip end cover 90 is configured to hold the clutch handle 14 at a set location. In other words, the tip end cover 90 is attached to the body 91, and thereby, an inner side surface of the tip end cover 90 comes into contact with an outer side surface of the clutch handle 14, which reduces the possibility that the clutch handle 14 is unintentionally rotated during work.
The body 91 is elongated along the forward/backward direction to be in the form of a rod as a whole. The body 91 is hollow and has an accommodation space in the interior thereof to accommodate the drive block A1, the clutch mechanism E1, the sensing unit 8, the support block 11, and other components.
The body 91 has a first window hole 911 through which light emitted from the first light source 101 is output to the outside. The first window hole 911 is provided in a front end surface of the body 91 and has a round opening.
The body 91 has a second window hole 912 through which light emitted from the second light source 102 is output to the outside. The second window hole 912 is provided in a lower end surface of the body 91 and has a rectangular opening.
The first light source 101 includes, for example, a shell-type Light Emitting Diode (LED) as a light source and outputs light through the first window hole 911. The second light source 102 includes, for example, a chip-type LED as a light source. The second light source 102 further includes a light transmissive member 104 to be fit in the second window hole 912 and outputs light through the light transmissive member 104 to the outside.
The body 91 has a front end to which the clutch handle 14 is to be attached. Moreover, the body 91 is configured to hold the pair of switches 16, the lock button 17, the gear change button 18, and the light button 103 such that these components are in an exposed state.
The grip 92 is configured to be easily gripped by a hand of a user during work. The grip 92 is elongated to be in the form of a rod. As shown in
The grip 92 is hollow and has the accommodation space in the interior thereof to accommodate the controller 4, the inverter circuit unit 13, the motor rotation measuring unit 15, and other components. The grip 92 has a rear end having a power supply attachment port to which the power source 6 is to be detachably attached. The power source 6 is attached to the power supply attachment port, and thereby, the power source 6 is electrically connected to the controller 4 and the inverter circuit unit 13. Note that at a time point at which the power source 6 is attached, the controller 4 enters into a standby state.
The pair of switches 16 are provided to respective left and right side surfaces at a rear end of the body 91 in the vicinity of the grip 92. Each switch 16 is a switch for starting/stopping the rotation of the output shaft 3. As long as a center part 160 of each switch 16 is located at the center, the electric tool 1 keeps the rotation of the output shaft 3 in a stop state. When the center part 160 of any switch 16 is pressed forward or rearward, the electric tool 1 starts the rotation of the output shaft 3. In particular, each switch 16 is configured to receive a selection of forward rotation of the tip tool 2 or reverse rotation of the tip tool 2 depending on whether each switch 16 is pressed frontward or rearward.
For example, when the switch 16 on the right side surface is pressed frontward, the electric tool 1 executes the forward rotation, and when the switch 16 on the right side surface is pressed rearward, the electric tool 1 executes the reverse rotation. In contrast, when the switch 16 on the left side surface is pressed frontward, the electric tool 1 executes the reverse rotation, and when the switch 16 on the left side surface is pressed rearward, the electric tool 1 executes the forward rotation. Depending on whether a user uses the electric tool 1 in the pistol-style or the straight-style, the user may differently hold the grip 92 to operate the switch 16 on the right side surface or the switch 16 on the left side surface by his/her first finger.
Note that as described above, the electric tool 1 of the present embodiment includes the trigger controller TR1 configured to receive an operation for controlling the rotational speed of the tip tool 2. Therefore, the switches 16 may be omitted. That is, the switches 16 are not essential components for the electric tool 1. Alternatively, in addition to rotational speed control by the trigger controller TR1, the rotational speed may also be controlled based on the manipulative variable indicating how deep each switch 16 has been pressed.
The lock button 17 is a button for mechanically restricting (locking) displacement of the pair of switches 16. When the lock button 17 is in a rearwardly pressed state (in the state shown in
The gear change button 18 is a button for changing the gear ratio of the speed changer 12 to switch the rotational speed of the output shaft 3 to a high speed or a low speed. When the gear change button 18 is in a rearwardly pressed state (in the state shown in
The light button 103 is a button for turning on the first light source 101 and the second light source 102. The electric tool 1 further includes a lighting circuit (the detailed description of which is omitted) for turning on these light sources in accordance with an operation given to the light button 103. For example, each time a press operation is given to the light button 103, turning on only the first light source 101, turning on only the second light source 102, turning on both the light sources, and turning off both the light sources are sequentially switched. A user turns on one of the first light source 101 or the second light source 102, or both of the first light source 101 and the second light source 102, thereby suppressing the workability from being reduced even in a dark work environment.
As shown in
The sensing unit 8 is electrically connected to the controller 4. The controller 4 acquires from the sensing unit 8 an output value corresponding to a sensing result of the pressing force. The controller 4 then adjusts the rotational speed of the output shaft 3 in accordance with the magnitude (output value) of an output from the pressure-sensitive sensor 80.
The arrangement of the pressure-sensitive sensor 80 relative to the axial direction of the output shaft 3 is not particularly limited, but when viewed in the radial direction of the output shaft 3 as shown in
The support block 11 is a part for supporting the sensing unit 8. When the clutch handle 14 is rotated by a finger of a user, the support block 11 rotates rearward along with the rotation of the clutch handle 14 and transmits adjustment force to the clutch mechanism E1 to perform a setting relating to torque (strength of tightening the work target 100). The support block 11 will be described in detail later.
The support block 11 is configured to support the sensing unit 8. The support block 11 is disposed backward of the chuck 7 so as to be covered with the clutch handle 14. The support block 11 is attached to the gear case 120 and is positioned by the clutch handle 14.
The support block 11 as a whole has a substantially cylindrical shape having a through hole 11A penetrating the support block 11 in the axial direction (corresponding to the forward/backward direction) thereof. The output shaft 3 extends through the through hole 11A and protrudes forward beyond the support block 11. As shown in
As shown in
Moreover, the body 110 is configured such that when the clutch handle 14 is rotated by a finger of a user, the entirety of the support block 11 rotates along with the rotation of the clutch handle 14 and transmits its adjustment force to the clutch mechanism E1. The body 110 has three projections 1103 (see
The support 112 is in the form of a flat ring-shaped plate. As shown in
In the present embodiment, the number of pressure-sensitive sensors 80 is, for example, one, and therefore, the one pressure-sensitive sensor 80 is disposed in one (positioning groove 1120 on a lower side) of the three positioning grooves 1120. The pressure-sensitive sensor 80 may be fixed to the positioning groove 1120 with an adhesive agent or the like.
If the number of pressure-sensitive sensors 80 is two or three, the pressure-sensitive sensors 80 may be disposed in the remaining positioning grooves 1120. In other words, the number of pressure-sensitive sensors 80 is not particularly limited, and the electric tool 1 may include a plurality of pressure-sensitive sensors 80 (see
Alternatively, the sensing unit 8 may be configured as one ring-like sheet unit. The plurality of pressure-sensitive sensors 80 may be arranged on the sheet unit to surround the output shaft 3. In this case, the positioning groove 1120 may be formed as one ring-like groove such that the ring-like sheet unit is positioned, or the positioning groove 1120 itself may be omitted.
The support 112 has three projections 1121 protruding outward from the outer edge thereof in a similar manner to the three projections 1103 of the body 110. The three projections 1121 are aligned along the circumferential direction at substantially equal intervals when viewed along the axial direction of the support 112. The three projections 1121 are fit in the respective three groove parts 140 of the clutch handle 14. Thus, when the clutch handle 14 is rotated by a finger of a user, the support 112, together with the clutch handle 14, rotates relative to the output shaft 3 extending through the through hole 112A.
The transfer part 111 is in the form of a flat ring-shaped plate. The transfer part 111 has, for example, substantially the same shape and substantially the same dimension as the support 112. As shown in
In this embodiment, the transfer part 111 is disposed to face the front surface of the support 112. In other words, the transfer part 111 is disposed to face the pressure-sensitive sensor 80 and is configured to transfer pressing force to the pressure-sensitive sensor 80 by coming into contact with the pressure-sensitive sensor 80. The output shaft 3 rotates relative to the support 112 and the transfer part 111. As shown in
Note that the transfer part 111 has a pair of positioning parts 1112 (see
When the tip tool 2 receives the pressing force in the pressing direction D1, the output shaft 3 and the chuck 7 retract together with the tip tool 2. At this time, a rear end of the chuck 7 comes into contact with and presses the transfer part 111, and thereby, the transfer part 111 receives the pressing force from the tip end of the tip tool 2. As a result, the contact 113 of the transfer part 111 comes into contact with and presses a surface of the pressure-sensitive sensor 80 disposed in the positioning groove 1120 facing the contact 113.
Even when the trigger controller TR1 receives an operation during the process of pressing and the output shaft 3 and the chuck 7 start rotating, the three projections 1111 are fit in the respective three groove parts 140, and the transfer part 111 does thus not rotate. Similarly, the support 112 and the body 110 do not rotate even when the output shaft 3 and the chuck 7 start rotating. In sum, the pressure-sensitive sensor 80 is disposed between two members (the support 112 and the transfer part 111) which do not rotate along with the rotation of the output shaft 3 even when the output shaft 3 starts rotating. This can reduce the possibility that the surface of the pressure-sensitive sensor 80 is scraped and scratched as the output shaft 3 rotates. As a result, the reliability relating to rotation control can be suppressed from decreasing.
Note that the contact 113 facing the pressure-sensitive sensor 80 may be slightly in contact with, or may be separated from, the pressure-sensitive sensor 80 in a state where the contact 113 receives no pressing force.
As described above, the pressure-sensitive sensor 80 of the present embodiment is supported by the support 112 such that the pressure-sensitive sensor 80 receives the pressing force in a direction (pressing direction D1) from the tip end of the tip tool 2 toward the output shaft 3. Note that in the present disclosure, as an example of a structure that “receives pressing force in the pressing direction D1”, the pressure-sensitive sensor 80 is supported such that a surface of the pressure-sensitive sensor 80 is substantially orthogonal to the axial direction (Y-axial direction) of the output shaft 3. However, it is not essential that the surface of the pressure-sensitive sensor 80 is substantially orthogonal to the axial direction of the output shaft 3. The pressure-sensitive sensor 80 may be tilted, if the pressure-sensitive sensor 80 is supported such that regarding the pressing force first component force in a direction orthogonal to the surface of the pressure-sensitive sensor 80 is dominant over second component force in a parallel direction to the surface. Specifically, the pressure-sensitive sensor 80 may be supported such that the surface of the pressure-sensitive sensor 80 is tilted to form an angle of 45 degrees or smaller with respect to the X-Z plane.
The controller 4 includes a computer system including one or more processors and a memory. At least some of the functions of the controller 4 are implemented by making the processor of the computer system execute a program stored in the memory of the computer system. The program may be stored in the memory. The program may also be downloaded via a telecommunications network such as the Internet or may be distributed after having been stored in a non-transitory storage medium such as a memory card.
The controller 4 performs, for example, time differentiation based on the angle of rotation of the electric motor 5 measured by the motor rotation measuring unit 15 to calculate the angular velocity of the electric motor 5 (angular velocity of the rotary shaft). The controller 4 performs PWM control of the inverter circuit unit 13 to control electric power to be supplied to the electric motor 5. In particular, the controller 4 determines the target value of the drive voltage in accordance with the sensing result by the sensing unit 8 and controls the inverter circuit unit 13 to adjust the angular velocity of the electric motor 5. The inverter circuit unit 13 is controlled by the controller 4 to increase or reduce a drive current flowing through a coil of the electric motor 5, thereby adjusting the magnetic flux of a permanent magnet of the electric motor 5 to control the rotational frequency of the electric motor 5 (rotational frequency of the rotary shaft).
The controller 4 of the present embodiment is configured to control the rotation of the output shaft 3 in accordance with pressing force in the pressing direction D1 from the tip end of the tip tool 2 toward the output shaft 3. Here, the electric tool 1 has, as part of an operation range, a restriction range R0 (see
That is, for example, a user brings the tip end of the tip tool 2 attached to the output shaft 3 via the chuck 7 into contact with the work target 100 and further applies force pressing the work target 100 by the tip end of the tip tool 2. In this case, the tip end of the tip tool 2 receives counter force as stress from the work target 100, and the counter force is generated as the “pressing force” in the pressing direction D1. In sum, a user gives a push operation to the trigger controller TR1, and thereby, the electric tool 1 starts the rotation of the output shaft 3. However, in the present embodiment, the restriction range R0 is provided, and therefore, even when the trigger controller TR1 is pressed, the rotation of the output shaft 3 is not started unless the pressing force exceeds a prescribed value. The restriction range R0 will be described in more detail below.
As described above, the controller 4 acquires from the sensing unit 8 an output value corresponding to a sensing result of the pressing force. The output value is, for example, a voltage (value) which changes in accordance with the pressing force applied to the pressure-sensitive sensor 80. The controller 4 receives a sensing signal including the output value (voltage value) from the sensing unit 8. The “prescribed value” corresponds to the output value (voltage value).
When the controller 4 determines that the output value is less than or equal to a threshold, the controller 4 restricts the rotation of the output shaft 3. In particular, when the controller 4 determines that the output value is less than or equal to the threshold, the controller 4 mechanistically interrupts transmission of motive power from the electric motor 5 to the output shaft 3, thereby restricting the rotation of the output shaft 3. As used herein, “mechanistically interrupt” may be interruption by an electrical mechanism, interruption by a mechanical mechanism, or interruption by both the electrical mechanism and the mechanical mechanism. In this embodiment, for example, the electric tool 1 has a configuration that interrupts transmission of the motive power by both the electrical mechanism and the mechanical mechanism.
Specifically, the electric tool 1 further includes an interruption mechanism B1 and a lock mechanism C1 as shown in
The interruption mechanism B1 is configured to restrict, in the restriction range R0, the rotation of the output shaft 3 by an electrical cut-off. For example, the interruption mechanism B1 includes a contact part P1 (see
In this embodiment, for example, the contact part P1 is disposed in the inverter circuit unit 13 which is supplied with electric power from the power source 6 to generate a drive voltage for the electric motor 5. When the contact part P1 is in the opened state, the drive voltage is not given to the electric motor 5, and when the contact part P1 is switched to the closed state, the drive voltage is given to the electric motor 5. The contact part P1 is not limited to being disposed in the inverter circuit unit 13. However, the contact part P1 is preferably disposed in any of electric paths from the power source 6 to the electric motor 5 as shown in
When the controller 4 determines that the output value exceeds the first threshold, the controller 4 controls the contact part P1 such that the non-energized state is switched to the energized state. That is, rotation restriction of the electric motor 5 by the interruption mechanism B1 is removed, and consequently, rotation restriction of the output shaft 3 is also removed.
The lock mechanism C1 is configured to restrict, in the restriction range R0, the rotation of the output shaft 3 by a mechanical lock. As shown in
The lock mechanism C1 may, however, be provided separately from the clutch mechanism E1. For example, the lock mechanism C1 may include a driver to be controlled by the controller 4 such that the driver is driven to increase force with which the compression spring of the clutch mechanism E1 presses the spheres. When the controller 4 determines that the output value is less than or equal to a threshold (which may be the same as or different from the first threshold), the controller 4 may cause a drive current to flow to drive the driver and press the compression spring of the clutch mechanism E1 to increase the pushing force applied to the spheres such that the inner gear of the speed changer 12 is not rotated. When the controller 4 determines that the output value exceeds the threshold, the driving of the driver may be canceled.
Incidentally, the restriction range R0 of the present embodiment may include at least a first range R1 and a second range R2 as shown in
In the example shown in
Note that the electric tool 1 further has, as an operation range, a derestriction range R3 in which the rotation restriction of the output shaft 3 is removed. When the pressing force exceeds the pressing force N2, the operation range is switched from the restriction range R0 to the derestriction range R3.
In the present embodiment, the controller 4 maintains a state where the contact part P1 is opened in the first range R1. In other words, in the first range R1, the contact part P1 between the electric motor 5 and the power source 6 is opened, thereby the “electrical cut-off” is achieved.
When the pressing force exceeds the pressing force N1, that is, when the output value exceeds the first threshold, the controller 4 closes the contact part P1 to switch the operation range from the first range R1 to the second range R2. In the case of the lock mechanism C1 including the driver described above, the controller 4 cancels the driving of the driver when the pressing force exceeds the pressing force N1. As a result, in the second range R2, the non-rotatable state is released.
The controller 4, however, controls the inverter circuit unit 13 such that in the second range R2, even when the pressing force exceeds the pressing force N1, the driving voltage is not given to the electric motor 5 until the pressing force exceeds the pressing force N2, that is, until the output voltage exceeds the second threshold. In other words, also in the second range R2, transmission of the motive power from the electric motor 5 to the output shaft 3 is kept interrupted. The second range R2 is a range in which the inverter circuit unit 13 is in a standby state. The second range R2 is provided, and therefore, when the pressing force exceeds the pressing force N2, the inverter circuit unit 13 can immediately start rotary drive of the electric motor 5. Moreover, in the first range R1, an electric path to the electric motor 5 is interrupted, and therefore, as compared to the case where the electric path to the electric motor 5 is not interrupted, exhaustion of the power source 6 due to its self-discharge can be suppressed.
The controller 4 stores, in its memory (or an external storage of the controller 4), relationship information on association of a plurality of output values (voltage values) with a plurality of rotational frequencies. The present embodiment includes relationship information on a plurality of voltage values corresponding to the pressing force in a range from 0 [N] to 50 [N]. In other words, a control object of the controller 4 is, for example, a range in which the pressing force is 0 [N] to 50 [N] but is not particularly limited.
When the controller 4 determines that the output value exceeds the second threshold, the controller 4 thereafter controls the inverter circuit unit 13 such that the rotational frequency of the rotary shaft of the electric motor 5 is set to a rotational frequency corresponding to the output value. As a result, for example, the inverter circuit unit 13 is controlled such that the rotational speed of the output shaft 3 increases as the output value increases.
As described above, the electric tool 1 of the present embodiment has the restriction range R0, and therefore, even when force that presses the tip tool 2 is generated, the possibility that rotation of the tip tool 2 is immediately started is reduced. Thus, convenience can be improved. Note that the prescribed value (in the example shown in
Moreover, the electric tool 1 has the restriction range R0, and therefore, a user can manually tighten or manually loosen the work target 100 in the restriction range R0. In other words, the electric tool 1 has a manual mode (manual tightening mode) in which a user holding the electric tool 1 works by turning his/her wrist to rotate the electric tool 1. A user gives a push operation to the trigger controller TR1, in particular, presses the trigger controller TR1 to such an extent that the pressing force exceeds the prescribed value, and thereby, the user can easily switch the manual mode to an electrically driven (rotational speed control) mode.
In addition, not only the restriction range R0 is simply provided, but also the first range R1 and the second range R2 are also provided to the restriction range R0, and therefore, the possibility that the rotation of the output shaft 3 is started without an intention of a user is further reduced. Moreover, for example, the first range R1 can be used as a range in which manual tightening is possible, and the second range R2 can be used as a stand-by range. A user is aware of the provision of the second range R2, which further improves the workability. In particular, the provision of the second range R2 can reduce the possibility that while a user is performing manual tightening in the first range R1, the pressing force is unintentionally applied and the rotation of the output shaft 3 is started.
Note that the electric tool 1 may further include a notification means configured to notify a user of that the operation range has been switched from the first range R1 to the second range R2 or that the operation range has been switched from the restriction range R0 to the derestriction range R3. The notification means may be a mechanism (e.g., a spring member) provided to the trigger controller TR1 and configured to provide, for example, a click feeling at the time of switching of the operation range. Alternatively, the notification means may be an indicator provided to the housing 9 and include an indicator configured such that a light emitting state of the indicator changes in response to the switching of the operation range (a change in light color, or a change from continuous lighting to flashing lighting).
In addition, in the present embodiment, the pressure-sensitive sensor 80 senses the pressing force, therefore, the convenience can be improved while the electric tool 1 is suppressed from increasing in size. The controller 4 makes a determination by comparing the output value and the threshold with each other and restricts the rotation of the output shaft 3, and therefore, highly reliable restriction of the rotation of the output shaft 3 is possible. Moreover, since the pressure-sensitive sensor 80 senses the pressing force, the amount of stroke at the time of a push operation can be reduced.
Incidentally, the electric tool 1 of the present embodiment further includes, as shown in
The embodiment described above is merely an example of various embodiments of the present disclosure. Rather, the embodiment described above may be readily modified in various manners depending on a design choice or any other factor without departing from the scope of the present disclosure. Moreover, functions similar to those of the controller 4 of the electric tool 1 according to the embodiment described above may be implemented by a control method, a computer program, a non-transitory storage medium storing a computer program, or the like.
Next, variations of the embodiment described above will be enumerated one after another. The variations described below are applicable accordingly in combination. In the following description, the embodiment described above will be hereinafter sometimes referred to as a “basic example”.
The controller 4 of the electric tool 1 of the present disclosure includes a computer system. The computer system includes a processor and a memory as principal hardware components. The processor executes a program stored in the memory of the computer system, thereby implementing functions as the controller 4 in the present disclosure. The program may be stored in the memory of the computer system in advance, may be provided via a telecommunications network, or may be provided as a non-transitory recording medium such as a computer system-readable memory card, optical disc, or hard disk drive storing the program. The processor of the computer system may be made up of a single or a plurality of electronic circuits including a semiconductor integrated circuit (IC) or a largescale integrated circuit (LSI). The integrated circuit such as IC or LSI mentioned herein may be referred to in another way, depending on the degree of the integration and includes integrated circuits called system LSI, very-large-scale integration (VLSI), or ultra-large-scale integration (ULSI). Optionally, a field-programmable gate array (FPGA) to be programmed after an LSI has been fabricated or a reconfigurable logic device allowing the connections or circuit sections inside of an LSI to be reconfigured may also be adopted as the processor. The plurality of electronic circuits may be collected on one chip or may be distributed on a plurality of chips. The plurality of chips may be collected in one device or may be distributed in a plurality of devices. As mentioned herein, the computer system includes a microcontroller including one or more processors and one or more memories. Thus, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.
Collecting the plurality of functions in the controller 4 in one housing is not an essential configuration. The components of the controller 4 may be distributed in a plurality of housings. In contrast, the plurality of functions in the controller 4 may be collected in one housing as in the case of the basic example. Still alternatively, at least some functions of the controller 4 (e.g., some functions of the controller 4) may be implemented as a cloud computing system as well.
In the basic example, the restriction range R0 includes two ranges, namely, the first range R1 and the second range R2. However, the restriction range R0 may have three or more ranges, and rotation restriction may be controlled with more finely divided stages. Moreover, the second range R2 of the basic example may be omitted, and in this case, the pressing force N2 may correspond to the first threshold.
In the basic example, the support block 11 has both a function of supporting the sensing unit 8 and a function of transmitting the adjustment force to the clutch mechanism E1. However, the support block 11 may be provided separately from a member that transfers the adjustment force to the clutch mechanism E1.
In the basic example, the number of pressure-sensitive sensors 80 is one as shown in
Alternatively, in the configuration in which the electric tool 1 includes a plurality of pressure-sensitive sensors 80, the controller 4 may cause the output shaft 3 to start rotating when the values of all of outputs from the plurality of pressure-sensitive sensors 80 exceed the threshold. In this case, for example, the possibility that the output shaft 3 starts rotating without an intention of a user is reduced.
As described above, an electric tool (1) of a first aspect includes an output shaft (3) and a controller (4). The output shaft (3) is configured to hold a tip tool (2) and be rotated by motive power provided from an electric motor (5) with the output shaft (3) holding the tip tool (2). The controller (4) is configured to control rotation of the output shaft (3) in accordance with pressing force in a direction from a tip end of the tip tool (2) toward the output shaft (3). The electric tool (1) has, as an operation range, a restriction range (R0) in which the rotation of the output shaft (3) is restricted in a state where the pressing force is less than or equal to a prescribed value. With the first aspect, convenience is improved.
In an electric tool (1) of a second aspect referring to the first aspect, the prescribed value is greater than a value of a self-weight of the electric tool (1). With the second aspect, the possibility that the rotation of the output shaft (3) is started without an intention of a user is reduced.
An electric tool (1) of a third aspect referring to the first or second aspect further includes a pressure-sensitive sensor (80) configured to sense the pressing force. With the third aspect, convenience is improved while the size of the electric tool (1) is suppressed from increasing.
In an electric tool (1) of a fourth aspect referring to the third aspect, the controller (4) is configured to acquire an output value as a sensing result of the pressing force from the pressure-sensitive sensor (80). The controller (4) is configured, when determining that the output value is less than or equal to a threshold, to restrict the rotation of the output shaft (3). With the fourth aspect, the rotation of the output shaft (3) is restricted with increased reliability.
In an electric tool (1) of a fifth aspect referring to the fourth aspect, the controller (4) is configured, when determining that the output value is less than or equal to the threshold, to mechanistically interrupt transmission of the motive power from the electric motor (5) to the output shaft (3) to restrict the rotation of the output shaft (3). With the fifth aspect, the rotation of the output shaft (3) is restricted with further increased reliability.
In an electric tool (1) of a sixth aspect referring to any one of the first to fifth aspects, the restriction range (R0) includes at least a first range (R1) and a second range (R2). The first range (R1) is a range in which the rotation of the output shaft (3) is restricted by at least one of a mechanical lock or an electrical cut-off and the output shaft (3) is in a non-rotatable state. The second range (R2) is a range in which the non-rotatable state is released and the motive power of the electric motor (5) is maintained at zero. With the sixth aspect, the first range (R1) and the second range (R2) are provided, which reduces the possibility that the rotation of the output shaft (3) is started without an intention of a user. Moreover, for example, the first range (R1) is usable as a range in which manual tightening may be performed.
In an electric tool (1) of a seventh aspect referring to the sixth aspect, the electric motor (5) is configured be supplied with electric power from a power source (6) and give the motive power to the output shaft (3). In the first range (R1), a contact part (P1) between the electric motor (5) and the power source (6) is opened to achieve the electrical cut-off. With the seventh aspect, the possibility that the rotation of the output shaft (3) is started without an intention of a user is reduced. In addition, electric power consumption (exhaustion) of the power source (6) in the first range (R1) can be suppressed.
An electric tool (1) of an eighth aspect referring to any one of the first to seventh aspects further includes an interruption mechanism (B1) configured to restrict the rotation of the output shaft (3) by an electrical cut-off in the restriction range (R0). With the eighth aspect, for example, the rotation of the output shaft (3) is restricted by a simple configuration as compared to, for example, the case where the rotation of the output shaft (3) is restricted by the mechanical lock.
An electric tool (1) of a ninth aspect referring to any one of the first to eighth aspects further includes a lock mechanism (C1) configured to restrict the rotation of the output shaft (3) by a mechanical lock in the restriction range (R0). The ninth aspect enables the possibility that the output shaft (3) rotates to be reduced, for example, manually, and enables the electric tool (1) to be used for manual tightening.
An electric tool (1) of a tenth aspect referring to any one of the first to ninth aspects further includes an operating unit (10). The operating unit (10) is configured to receive an operation input to switch the operation range to the restriction range (R0) or a derestriction range (R3) in which rotation restriction of the output shaft (3) is removed. With the tenth aspect, convenience is further improved.
Note that constituent elements according to the second to tenth aspects are not essential constituent elements for the electric tool (1) but may be omitted as appropriate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-186369 | Oct 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/035458 | 9/18/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/070596 | 4/15/2021 | WO | A |
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| Number | Date | Country | |
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| 20230120149 A1 | Apr 2023 | US |
