JP2021079509A - Electric tool, control method, and program - Google Patents

Abstract

To improve the convenience of an electric tool.SOLUTION: An electric tool 1 is equipped with a motor 15, an operating portion 29 that receives operation from a user, a control portion 4 that controls rotary action of the motor 15 according to operation to the operating portion 29, a transmission mechanism 18 that transmits rotation force of the motor 15 to a tip end tool working to a workpiece, and a housing that stores at least the motor 15 and the transmission mechanism 18. The control portion 4 has a detecting function (movement detecting portion 49) that detects steep movement of the housing with respect to the workpiece, on the basis of at least either one of a torque current or an excitation current supplied to the motor 15.SELECTED DRAWING: Figure 1

Description

The present disclosure relates generally to power tools, control methods, and programs, and more specifically to power tools that control motors using vector control, power tool control methods, and programs.

Patent Document 1 discloses a power tool. The power tool described in Patent Document 1 includes a motor, a trigger switch, a control unit, and a chuck. The control unit controls the rotation speed of the motor based on the pull-in amount of the trigger switch. A tip tool such as a hole saw can be attached to and detached from the chuck. The motor is driven by the control unit when the trigger switch is pulled in. As a result, the tip tool rotates, and work such as drilling is possible.

JP-A-2017-030112

In an electric tool as described in Patent Document 1, if the tip tool bites the work object during the drilling work of a work object such as a plate material, the rotation of the tip tool may be hindered. In that case, the tool body (housing) may rotate with respect to the work object around the tip tool, causing a steep movement of the tool body. If the tool body may move abruptly, the user will be prepared for the movement, which may reduce the usability of the power tool for the user.

The present disclosure has been made in view of the above reasons, and an object of the present disclosure is to improve the usability of the power tool.

The power tool according to one aspect of the present disclosure includes a motor, an operation unit, a control unit, a transmission mechanism, and a housing. The operation unit receives an operation from the user. The control unit uses vector control to control the rotational operation of the motor in response to an operation on the operation unit. The transmission mechanism transmits the rotational force of the rotating shaft of the motor to the tip tool that performs the work on the work object. The housing houses at least the motor and the transmission mechanism. The control unit has a detection function. In the detection function, the control unit detects a steep movement of the housing with respect to the work target or a sign thereof, based on at least one of a torque current and an exciting current supplied to the motor.

The control method according to one aspect of the present disclosure is a power tool control method. The power tool includes a motor, an operation unit, a transmission mechanism, and a housing. The operation unit receives an operation from the user. The transmission mechanism transmits the rotational force of the rotating shaft of the motor to the tip tool that performs the work on the work object. The housing houses at least the motor and the transmission mechanism. The control method includes controlling the rotational operation of the motor in response to an operation on the operation unit by utilizing vector control. The control method includes detecting a steep movement of the housing with respect to the work object or a sign thereof, based on at least one of a torque current and an exciting current supplied to the motor.

The program according to one aspect of the present disclosure is a program for causing one or more processors to execute the control method.

According to the present disclosure, there is an advantage that the usability of the power tool can be improved.

FIG. 1 is a block diagram of a power tool according to an embodiment. FIG. 2 is a schematic view of the same power tool. FIG. 3 is an explanatory diagram of vector control by the control unit of the same power tool. FIG. 4 is a graph showing an operation example of the same power tool. FIG. 5 is a flowchart showing a control method of the same power tool.

Hereinafter, the power tool 1 according to the embodiment will be described with reference to the drawings. However, the following embodiments are only one of the various embodiments of the present disclosure. The following embodiments can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. Further, each figure described in the following embodiment is a schematic view, and the ratio of the size and the thickness of each component in the figure does not necessarily reflect the actual dimensional ratio. ..

(1) Outline As shown in FIGS. 1 and 2, the power tool 1 includes a motor 15, an operation unit 29, a control unit 4, a transmission mechanism 18, and a housing 9.

The operation unit 29 receives an operation from the user. The control unit 4 uses vector control to control the rotational operation of the motor 15 in response to an operation on the operation unit 29. The transmission mechanism 18 transmits the rotational force of the rotating shaft 16 of the motor 15 to the tip tool 28 that performs work on the work target 100. The housing 9 houses at least the motor 15 and the transmission mechanism 18. The tip tool 28 is, for example, a socket bit, a wrench bit, a driver bit, a Torx (registered trademark) bit, or the like. The work target 100 is, for example, wood, a wall, or the like.

The control unit 4 has a detection function. The detection function is a function of detecting a steep movement of the housing 9 with respect to the work target 100 or a sign thereof. In the detection function, the control unit 4 detects a steep movement of the housing 9 with respect to the work target 100 or a sign thereof, based on at least one of the torque current and the exciting current supplied to the motor 15.

Further, when the power tool 1 detects a steep movement of the housing 9 or a sign thereof, it executes a protective operation for suppressing the steep movement of the housing 9. In one example, the control unit 4 reduces the speed of the motor 15 or stops the motor 15 as a protective operation. Here, the control unit 4 stops the motor 15 as a protective operation.

In the detection function of the power tool 1, a steep movement of the housing 9 or a sign thereof is detected based on the torque current and / or the exciting current supplied to the motor 15. Therefore, the control unit 4 can take measures such as stopping the motor 15 in response to the sudden movement of the housing 9 or the detection of a sign thereof. Therefore, the usability of the power tool 1 can be improved by providing the detection function.

The torque current and exciting current used in the detection function are also used for vector control of the motor 15. Therefore, it is not necessary to newly add a dedicated sensor (for example, an acceleration sensor) for detecting the movement of the housing 9, and it is possible to suppress an increase in size and cost of the power tool 1.

(2) Details (2.1) Power tool The power tool 1 of the present embodiment will be described in more detail with reference to the drawings. The power tool 1 of this embodiment is a so-called impact tool. The impact tool is used as, for example, an impact driver, a hammer drill, an impact drill, an impact drill driver or an impact wrench. In this embodiment, as a typical example, a case where the power tool 1 is used as an impact driver will be described.

As shown in FIGS. 1 and 2, the power tool 1 includes a motor 15, a transmission mechanism 18, an output shaft 21, a socket 23, a tip tool 28, a power supply unit 32, an operation unit 29, and a control unit. 4, an inverter circuit unit 51, and a housing 9.

The housing 9 houses the motor 15, the transmission mechanism 18, the control unit 4, the inverter circuit unit 51, and a part of the output shaft 21. The housing 9 is made of, for example, resin. The housing 9 has a body portion 91 and a grip portion 92. The shape of the body portion 91 is cylindrical. The grip portion 92 protrudes from the body portion 91.

The motor 15 is a brushless motor. In particular, the motor 15 of the present embodiment is a synchronous motor, and more specifically, a permanent magnet synchronous motor (PMSM (Permanent Magnet Synchronous Motor)). The motor 15 includes a rotor 13 having a permanent magnet 131 and a stator 14 having a coil 141. The rotor 13 has a rotating shaft 16 that outputs rotational power. The rotor 13 rotates with respect to the stator 14 due to the electromagnetic interaction between the coil 141 and the permanent magnet 131.

The output shaft 21 is a portion that rotates by a driving force transmitted from the motor 15 via the transmission mechanism 18. The socket 23 is fixed to the output shaft 21. A tip tool 28 is detachably attached to the socket 23. That is, the tip tool 28 is connected to the output shaft 21. The tip tool 28 rotates together with the output shaft 21.

The electric tool 1 rotates the tip tool 28 by rotating the output shaft 21 by the driving force of the motor 15. That is, the electric tool 1 is a tool that drives the tip tool 28 with the driving force of the motor 15. Of the various tip tools 28, the tip tool 28 according to the application is attached to the socket 23 and used. The tip tool 28 may be directly attached to the output shaft 21.

The power tool 1 of the present embodiment is provided with the socket 23 so that the tip tool 28 can be replaced according to the application, but it is not essential that the tip tool 28 can be replaced. For example, the power tool 1 may be a tool that can be used only by a specific tip tool 28.

The tip tool 28 of this embodiment is a driver bit for tightening or loosening the tightening member 30 (screw). More specifically, the tip tool 28 is a Phillips driver bit having a tip 280 formed in a + (plus) shape. That is, the output shaft 21 holds a driver bit for tightening or loosening a screw, and receives power from the motor 15 to rotate. The type of screw is not particularly limited and may be, for example, a bolt, a screw or a nut.

The transmission mechanism 18 includes an impact mechanism 17, a planetary gear mechanism 25, and a drive shaft 22. The transmission mechanism 18 transmits the rotational power of the rotary shaft 16 of the motor 15 to the output shaft 21. More specifically, the transmission mechanism 18 adjusts the rotational power of the rotary shaft 16 of the motor 15 and outputs it as the rotation of the output shaft 21.

The rotating shaft 16 of the motor 15 is connected to the planetary gear mechanism 25. The drive shaft 22 is connected to the planetary gear mechanism 25 and the impact mechanism 17. The planetary gear mechanism 25 decelerates the rotational power of the rotating shaft 16 of the motor 15 at a predetermined reduction ratio and outputs it as the rotation of the drive shaft 22.

The impact mechanism 17 is connected to the output shaft 21. The impact mechanism 17 transmits the rotational power of the motor 15 (rotary shaft 16) received via the planetary gear mechanism 25 and the drive shaft 22 to the output shaft 21.

The impact mechanism 17 performs a striking operation according to the magnitude of the torque applied to the output shaft 21. The impact mechanism 17 applies a striking force to the output shaft 21 in the striking operation.

As shown in FIG. 2, the impact mechanism 17 includes a hammer 19, an anvil 20, and a spring 24. The hammer 19 is attached to the drive shaft 22 via a cam mechanism. The anvil 20 is in contact with the hammer 19 and rotates integrally with the hammer 19. The spring 24 pushes the hammer 19 toward the anvil 20. The anvil 20 is integrally formed with the output shaft 21. The anvil 20 may be formed separately from the output shaft 21 and fixed to the output shaft 21.

When the load (torque) applied to the output shaft 21 is smaller than a predetermined threshold value, the impact mechanism 17 continuously rotates the output shaft 21 by the rotational power of the motor 15. That is, in this case, the drive shaft 22 and the hammer 19 connected by the cam mechanism rotate integrally, and the hammer 19 and the anvil 20 rotate integrally, so that the output shaft integrally formed with the anvil 20 is formed. 21 rotates with the drive shaft 22.

On the other hand, when a load equal to or higher than a predetermined threshold is applied to the output shaft 21, the impact mechanism 17 performs a striking operation. In the striking operation, the impact mechanism 17 converts the rotational power of the motor 15 into a pulsed torque to generate a striking force. That is, in the striking motion, the hammer 19 retracts against the spring 24 (away from the anvil 20) while being regulated by the cam mechanism between the hammer 19 and the drive shaft 22. When the connection between the hammer 19 and the anvil 20 is broken due to the retreat of the hammer 19, the hammer 19 advances while rotating (moves to the output shaft 21 side) and applies a striking force in the rotational direction to the anvil 20 to output. Rotate the shaft 21. That is, the impact mechanism 17 applies a rotational impact around the shaft (output shaft 21) to the output shaft 21 via the anvil 20. In the striking operation of the impact mechanism 17, the hammer 19 repeatedly applies a striking force in the rotational direction to the anvil 20. Each time the hammer 19 moves backward and forward, a striking force is generated once.

The power supply unit 32 supplies a current for driving the motor 15. The power supply unit 32 is, for example, a battery pack. The power supply unit 32 includes, for example, one or more secondary batteries. The power supply unit 32 is detachably attached to, for example, the grip unit 92.

The operation unit 29 includes a trigger switch. The trigger switch protrudes from the grip portion 92. The on / off of the motor 15 can be switched by pulling the trigger switch. In addition, the rotation speed of the motor can be adjusted by the pull-in amount of the operation of pulling the trigger switch. As a result, the rotation speed of the output shaft 21 can be adjusted by the pull-in amount of the operation of pulling the trigger switch. The larger the pull-in amount, the faster the rotation speed of the motor 15 and the output shaft 21. The control unit 4 rotates or stops the motor 15 and the output shaft 21 according to the pull-in amount of the operation of pulling the trigger switch, and also controls the rotation speed of the motor 15 and the output shaft 21. In the power tool 1, the tip tool 28 is connected to the output shaft 21 via the socket 23. Then, the rotation speed of the tip tool 28 is controlled by controlling the rotation speed of the motor 15 and the output shaft 21 by operating the trigger switch.

More specifically, the trigger switch includes a multi-step switch or a stepless switch (variable resistor) that outputs an operation signal. The operation signal changes according to the operation amount (pull-in amount) to the trigger switch. _{The trigger switch determines the target value ω 1} ^* of the speed (rotation speed) of the motor 15 according to the operation signal and gives it to the control unit 4. The control unit 4 controls the rotation of the motor 15 based on _{the target value ω 1} ^{* received from the trigger switch.}

The inverter circuit unit 51 is a circuit for driving the motor 15. The inverter circuit unit 51, the voltage _{V dc} from the power supply unit 32, and converts the driving voltage _{V a} of the motor 15. In the present embodiment, the driving voltage V _a is a three-phase AC voltage including a U-phase voltage, V-phase voltage and the W-phase voltage. In the following, the U-phase voltage is represented by v _u , the V-phase voltage is represented _{by v v} , and the W-phase voltage is _{represented by v w, if necessary.} Each voltage v _u , v _v , v _w is a sinusoidal voltage.

The inverter circuit unit 51 can be realized by using a PWM inverter and a PWM converter. The PWM converter pulses according to the target value (voltage command value) v _u ^* , v _v ^* , v _w ^* of the drive voltage V _a (U-phase voltage v _u , V-phase voltage v _v , W-phase voltage v _w). Generates a width-modulated PWM signal. _{The PWM inverter drives the motor 15 by applying a} drive voltage Va (v u, v _v , v _w ) corresponding to the PWM signal to the motor 15. More specifically, the PWM inverter includes a half-bridge circuit for three phases and a driver. The PWM inverter, by the driver to turn on / off the switching element in each half bridge circuit in accordance with the PWM signal, * the voltage command value ^{_{v u, v v *, v}} w * driving voltage in accordance with _V a _(v u, _{v v} , v _w ) is given to the motor 15. Thus, the motor 15, the driving voltage _{V a (v u, v v} , v w) drive current corresponding to the supplied. The drive current includes a U-phase current i _u , a V-phase current i _v , and a W-phase current i _w . More specifically, the U-phase current i _u , the V-phase current i _v , and the W-phase current i _w are the current of the U-phase armature winding and the V-phase armature winding in the stator 14 of the motor 15. And the current of the W-phase armature winding.

The control unit 4 determines _{the command value ω 2} ^* of the speed of the motor 15 based on _{the target value ω 1} ^* of the speed of the motor 15 given by the operation unit 29. The control unit 4, so that the speed of the motor 15 matches the command value omega ₂ ^*, the drive voltage _V target value of _a (voltage command ^{_{value) v u *, v v *}} , and determines the _v ^{w *} , Is given to the inverter circuit unit 51.

(2.2) Control Unit The control unit 4 will be described in more detail below. In the present embodiment, the control unit 4 controls the motor 15 by using vector control. Vector control is a motor control method that decomposes the motor current into a current component (torque current) that generates torque (torque force) and a current component (excitation current) that generates magnetic flux, and controls each current component independently. It is a kind of.

FIG. 3 is an analysis model diagram of the motor 15 in vector control. FIG. 3 shows U-phase, V-phase, and W-phase armature winding fixed shafts. In vector control, a rotating coordinate system that rotates at the same speed as the rotation speed of the magnetic flux created by the permanent magnet 131 provided in the rotor 13 of the motor 15 is taken into consideration. In the rotating coordinate system, the direction of the magnetic flux created by the permanent magnet 131 is taken as the d-axis, and the controlled rotating axis corresponding to the d-axis is taken as the γ-axis. Further, the q-axis is taken as the phase advanced by 90 degrees in the electric angle from the d-axis, and the δ-axis is taken as the phase advanced by 90 degrees in the electric angle from the γ-axis. The rotating coordinate system corresponding to the real axis is a coordinate system in which the d-axis and the q-axis are selected as the coordinate axes, and the coordinate axes are called the dq-axis. The control rotating coordinate system is a coordinate system in which the γ-axis and the δ-axis are selected as the coordinate axes, and the coordinate axes are called the γδ-axis.

The dq axis is rotating, and its rotation speed is represented by ω. The γδ axis is also rotating, and its rotation speed is represented _{by ω e.} Further, on the dq axis, the angle (phase) of the d axis as seen from the U-phase armature winding fixed axis is represented by θ. Similarly, on the γδ axis, the angle (phase) of the γ axis as seen from the U-phase armature winding fixed axis is represented _{by θ e.} The angles represented by θ and θ _e are angles in electrical angles, which are also commonly referred to as rotor positions or magnetic pole positions. The rotation speed represented by ω and ω _e is the angular velocity at the electric angle. Hereinafter, if necessary, θ or θ _e may be referred to as a rotor position, and ω or ω _e may be simply referred to as a velocity.

The control unit 4 basically performs vector control so that _{θ and θ e match.} When θ and θ _e coincide with each other, the d-axis and the q-axis coincide with the γ-axis and the δ-axis, respectively. In the following description, if necessary, the gamma-axis component and [delta] -axis component of the drive voltage V _a, respectively expressed in gamma-axis voltage v _gamma and [delta] -axis voltage v _[delta], gamma-axis component and [delta] axis of the drive current The components are represented by the γ-axis current i _γ and the δ-axis current i _δ , respectively.

Further, the voltage command values representing the target values of the γ-axis voltage v _γ and the δ-axis voltage v _δ are represented by the γ-axis voltage command value v _γ ^* and the δ-axis voltage command value v _δ ^* , respectively. The current command values representing the target values of the γ-axis current i _γ and the δ-axis current i _δ are represented by the γ-axis current command value i _γ ^* and the δ-axis current command value i _δ ^* , respectively.

In the control unit 4, the values of the γ-axis voltage v _γ and the δ-axis voltage v _δ follow the γ-axis voltage command value v _γ ^* and the δ-axis voltage command value v _δ ^* , respectively, and the γ-axis current i _γ and the δ-axis current the value of i _[delta] is to follow the gamma-axis current value i _gamma ^* and [delta] -axis current value i _[delta] ^*, respectively, performs the vector control.

The control unit 4 includes a computer system having one or more processors and memories. When the processor of the computer system executes the program recorded in the memory of the computer system, at least a part of the functions of the control unit 4 are realized. The program may be recorded in a memory, provided through a telecommunication line such as the Internet, or may be recorded and provided on a non-temporary recording medium such as a memory card.

As shown in FIG. 1, the control unit 4 includes a coordinate converter 411, 412, a subtractor 421, 422, 423, a current control unit 43, a magnetic flux control unit 44, a speed control unit 45, and a position / speed. It includes an estimation unit 46, a step-out detection unit 47, a command value generation unit 48, and a movement detection unit 49. The coordinate converter 411, subtractor 421, 422, 423, current control unit 43, magnetic flux control unit 44, speed control unit 45, position / speed estimation unit 46, step-out detection unit 47, command value generation unit 48, and movement. The detection unit 49 does not necessarily show a substantive configuration. These show the functions realized by the control unit 4. Therefore, each element of the control unit 4 can freely use each value generated in the control unit 4. Further, the power tool 1 includes a plurality of current sensors 61 and 62 (two in FIG. 1).

Each of the plurality of current sensors 61, 62 includes, for example, a Hall element current sensor or a shunt resistance element. The plurality of current sensors 61 and 62 measure the current supplied from the power supply unit 32 to the motor 15 via the inverter circuit unit 51. The plurality of current sensors 61, 62 measure the current of at least two phases. In FIG. 1, the current sensor 61 _{measures the U-phase current i u} , and the current sensor 62 measures the V-phase current i _v . The W-phase current i _w can be obtained from the U-phase current i _u and the V-phase current i _v.

The coordinate converter (first coordinate converter) 411 transforms the U-phase current i _u and the V-phase current i _{v on the γ δ axis based on the rotor position θ e} , thereby performing the γ-axis current i γ and the _{γ-axis current i γ.} δ-axis current i _δ is calculated and output. Here, the γ-axis current i _γ is an exciting current corresponding to the d-axis current and hardly contributes to torque. The δ-axis current i _δ is a current that corresponds to the q-axis current and greatly contributes to torque. The rotor position θ _e is calculated by the position / velocity estimation unit 46.

The subtractor 423 refers to the velocity ω _e and the command value ω ₂ ^*, and calculates the velocity deviation (ω ₂ ^* −ω _{e) between the two.} The velocity ω _e is calculated by the position / velocity estimation unit 46.

The speed control unit 45 calculates and outputs the δ-axis current command value i _δ ^* _{so that the speed deviation (ω 2} ^* −ω _e ) converges to zero by using proportional integration control or the like.

The magnetic flux control unit 44 determines the γ-axis current command value i _γ ^* and outputs it to the subtractor 421. The γ-axis current command value i _γ ^* can take various values depending on the type of vector control executed by the control unit 4 and the speed ω of the motor 15. For example, when the maximum torque is controlled with the d-axis current set to zero, the γ-axis current command value i _γ ^* is set to 0. Further, when the d-axis current is passed to weaken the magnetic flux control, the γ-axis current command value i _γ ^* is set to a negative value according to the velocity ω _e. In the following description, the case where the γ-axis current command value i _γ ^* is 0 is dealt with.

_{The subtractor 421 subtracts the γ-axis current i γ} output from the coordinate converter 411 from the _{γ-axis current command value i γ} ^* output from the magnetic flux control unit 44 to obtain a current error (i _γ ^* −i _γ ). calculate. _{The subtractor 422 subtracts the δ-axis current i δ} output from the coordinate converter 411 from the _{value i δ} ^* output from the speed control unit 45, and calculates the current error (i _δ ^* −i _δ).

The current control unit 43 performs current feedback control using proportional integration control or the like so that both _{the current error (i γ} ^* −i _γ ) and (i _δ ^* −i _{δ) converge to zero.} At this time, non-interference control for eliminating the interference between the γ axis and the δ axis is used so that both (i _γ ^* −i _γ ) and (i _δ ^* −i _δ ) converge to zero. Calculate the γ-axis voltage command value v _γ ^* and the δ-axis voltage command value v _δ ^*.

The coordinate converter (second coordinate converter) 412 has _{γ-axis voltage command values v γ} ^* and δ given by the current control unit 43 based on the _{rotor position θ e output from the position / speed estimation unit 46.} By converting the shaft voltage command value v _δ ^* onto the three-phase fixed coordinate axes, the voltage command values (v _u ^* , v _v ^* and v _w ^* ) are calculated and output.

The position / velocity estimation unit 46 estimates the rotor position θ _e and the velocity ω _e . More specifically, the position / velocity estimation unit 46 uses all or a part _{of i γ} and i _{δ from the coordinate converter 411 and v γ} ^* and v _δ ^* from the current control unit 43 to be proportional. Perform integration control, etc. The position / velocity estimation unit 46 estimates the rotor position θ _e and the velocity ω _{e so that the axis error (θ e} − θ) between the d-axis and the γ-axis converges to zero. Various methods have been conventionally proposed as methods for estimating the rotor position θ _e and the velocity ω _e , and the position / velocity estimation unit 46 can adopt any known method.

The step-out detection unit 47 determines whether or not the motor 15 is step-out. More specifically, the step-out detection unit 47 determines whether or not the motor 15 is step-out based on the magnetic flux of the motor 15. The magnetic flux of the motor 15 is obtained from the d-axis current, the q-axis current, the γ-axis voltage command value v _γ ^*, and the δ-axis voltage command value v _δ ^* . If the amplitude of the magnetic flux of the motor 15 is less than the threshold value, the step-out detection unit 47 may determine that the motor 15 is step-out. The threshold value is appropriately determined based on the amplitude of the magnetic flux generated by the permanent magnet of the motor 15. Various methods have been conventionally proposed as the step-out detection method, and the step-out detection unit 47 can adopt any known method.

The command value generation unit 48 is a portion of the control unit 4 that obtains _{the command value ω 2} ^{* of the speed of the motor 15.} Here, the command value generation unit 48 sets _{the target value ω 1} ^* received from the operation unit 29 as the _{command value ω 2} ^* .

The movement detection unit 49 is the execution subject of the above-mentioned detection function. In the detection function, the movement detection unit 49 detects a steep movement of the housing 9 with respect to the work target 100 or a sign thereof based on at least one of the torque current and the exciting current supplied to the motor 15. In the detection function, the movement detection unit 49 detects a sudden increase in acceleration applied to the housing 9 based on at least one of the torque current and the exciting current supplied to the motor 15, and thus the housing 9 with respect to the work target 100. Detects a steep movement or a sign of it. In the present disclosure, when it is predicted that a steep movement of the housing 9 with respect to the work target 100 will occur from now on, there is a sign of a steep movement of the housing 9 with respect to the work target 100.

_{The movement detection unit 49 executes the detection function by using the γ-axis current i γ} calculated by the coordinate converter 411 as the measured value of the exciting current and the δ-axis current i _δ as the measured value of the torque current.

The steep movement of the housing 9 to be detected by the movement detection unit 49 includes, here, the movement of the housing 9 due to the reaction force from the work target 100. The sign of abrupt movement of the housing 9 to be detected by the movement detection unit 49 includes, here, a sudden increase in the acceleration applied to the housing 9 due to the reaction force from the work target 100.

For example, while tightening a screw (tightening member 30) to wood (working object 100) using an impact driver (see FIG. 2) as a power tool 1, the tip of the screw comes into contact with a hard portion of wood. In some cases. In this case, the rotation speed of the output shaft 21 decreases due to the sudden increase in the load received from the wood, while the motor 15 tries to maintain the speed of the rotation shaft 16 in an attempt to maintain the speed of the output shaft 21. To do. Therefore, in the main body of the motor 15 (the portion accommodating the stator 14) and the housing 9 holding the motor 15, the rotational force of the motor 15 due to the decrease in the rotational speed of the output shaft 21 is applied from the wood (work target 100). Acts as a reaction force of. Therefore, the housing 9 of the power tool 1 tries to rotate in the direction opposite to the rotation direction of the output shaft 21 (the steep movement of the housing 9).

The movement detection unit 49 of the control unit 4 of the power tool 1 of the present embodiment makes such a steep movement of the housing 9 (around the output shaft 21) based on at least one of the torque current and the exciting current, here both. (Rotation) or its sign is detected.

_{FIG. 4 shows an outline of the speed ω of the motor 15, the δ-axis current i δ} (torque current), and the γ-axis current i _γ (excitation current) when the screw is tightened to the work target 100 by the electric tool 1 (impact driver). An example is shown.

In FIG. 4, the supply of the electric current to the motor 15 starts at the time point t0, and the impact mechanism 17 starts the striking operation at the time point t1. Further, at the time point t2, the load applied to the output shaft 21 is increasing. In the following, for convenience, the period between the time points t0 to t1 may be referred to as the first period T1, the period between the time points t1 to t2 may be referred to as the second period T2, and the period after the time point t2 may be referred to as the third period T3.

In the first period T1, the speed ω of the motor 15 increases following the increase in the pull-in amount of the trigger switch (the increase in the command value ω ₂ ^{* of the motor 15).} Then, after t4 when the pull-in amount of the trigger switch becomes constant at the upper limit value, the speed ω of the motor 15 also converges to a constant value. In the first period T1, the load applied to the output shaft 21 does not exceed the threshold value at which the impact mechanism 17 starts the striking operation. Therefore, the impact mechanism 17 does not perform a striking operation, and the output shaft 21 rotates integrally with the drive shaft 22. Actually, when the speed ω of the motor 15 changes from the state of increasing to the state of being maintained at a constant value (time point t4), the speed ω of the motor 15 _{exceeds the command value ω 2} ^* by a predetermined amount or more. Some overshoots may occur, but are ignored here.

At the time point t1, the load applied to the output shaft 21 reaches the threshold value at which the impact mechanism 17 starts the striking operation. Then, in the second period T2 after the time point t1, the impact mechanism 17 performs a striking operation. In the second period T2, the velocity ω of the motor 15 vibrates around the _{command value ω 2} ^{* according to the striking operation of the impact mechanism 17.}

In the second period T2, the δ-axis current i _δ (torque current) oscillates around _{a predetermined value Ip δ} 1 according to the striking operation of the impact mechanism 17. Specifically, in the striking operation of the impact mechanism 17, the load applied to the rotating shaft 16 of the motor 15 gradually increases while the hammer 19 retracts. Then, when the connection between the hammer 19 and the anvil 20 is disengaged, the load applied to the rotating shaft 16 of the motor 15 is reduced. As described above, the control unit 4 controls so that the rotor position θ on the dq axis and the rotor position θ _{e on the} γδ axis coincide with each other. Therefore, when the load applied to the rotating shaft 16 of the motor 15 increases or decreases, the control unit 4 controls so as to compensate for the difference between _{θ and θ e} caused by this, so that the measured value of the _{δ-axis current i δ} Increases or decreases. Specifically, immediately after the load applied to the motor 15 becomes small, _{the measured value of the δ-axis current i δ} decreases, and at the moment when the load applied to the motor 15 increases, the measured value _{of the δ-axis current i δ decreases.} To increase. It should be noted that one round trip of the vibration of the δ-axis current i _δ in FIG. 4 corresponds to one striking operation by the impact mechanism 17.

Further, in the second period T2, the γ-axis current i _γ (exciting current) oscillates around a current value of zero according to the striking operation of the impact mechanism 17. _{That is, the control unit 4 controls so as to compensate the difference between θ and θ e} according to the increase or decrease of the load applied to the rotating shaft 16 of the motor 15, so that it is the same as the δ-axis current i _δ (details). In the opposite phase to the delta-axis current i _δ ), the γ-axis current i _γ oscillates. One round trip of the vibration of the γ-axis current i _γ in FIG. 4 corresponds to one striking operation by the impact mechanism 17.

In this way, the control unit 4 _{detects the presence or absence of vibration of the δ-axis current i δ} (torque current) or the γ-axis current i _γ (excitation current), thereby causing the impact mechanism 17 to perform a striking operation (striking operation). Start and end) can be detected. The control unit 4 detects the presence or absence of vibration of the δ-axis current i _δ or the γ-axis current i _γ by comparing the amplitude of the δ-axis current i _δ or the γ-axis current i _{γ with a predetermined threshold value, for example.} The amplitude of the current is defined as, for example, 1/2 of the difference between the maximum value and the minimum value of the current per unit time.

At the time point t2, the load applied to the screw increases rapidly, so that the load applied to the output shaft 21 increases. As shown in FIG. 4, in the third period T3 after the time point t2, the impact mechanism 17 continues the striking operation immediately after the time point (time point t2) when the load applied to the screw increases.

Here, in the third period T3, the load applied to the output shaft 21 increases as compared with the second period T2, and by extension, the load applied to the rotating shaft 16 of the motor 15 increases. In the third period T3, the control unit 4 increases the torque current (δ-axis current i _δ ) supplied to the motor 15 in accordance with the increase in the load applied to the rotating shaft 16. Therefore, in the third period T3, the δ-axis current i _δ (torque current) oscillates around _{a predetermined value Ip δ} 2 (> Ip _δ 1) according to the striking operation of the impact mechanism 17.

_{By detecting the increase in the δ-axis current i δ} (torque current), the movement detection unit 49 detects a steep movement of the housing 9 or a sign thereof due to an increase in the load applied to the rotating shaft 16. .. Specifically, the movement detection unit 49 detects that any one of the maximum value, the minimum value, and the average value of the torque current (δ-axis current i _{δ) has increased, so that the housing 9 is steep.} Detect movement or its signs. For example, when the movement detection unit 49 detects that the maximum value (or minimum value or average value) of the torque current per unit time is increased by a predetermined threshold value or more from the value immediately after the start of the striking operation, the housing It is determined that a steep movement has occurred in 9 or there is a sign thereof.

In short, the control unit 4 (movement detection unit 49) determines in the detection function that there is a steep movement of the housing 9 when the load applied to the rotating shaft 16 obtained based on the torque current becomes a predetermined value or more. The predetermined value here can be set to _{the above-mentioned predetermined value Ip δ} 1 when the detection target is, for example, the average value of the torque current.

Further, in the third period T3, as described above, the load applied to the output shaft 21 increases and the load applied to the rotating shaft 16 of the motor 15 increases as compared with the second period T2. _{Therefore, in the third period T3, the difference between θ and θ e} that occurs while the hammer 19 retracts in the striking operation of the impact mechanism 17 is larger than that in the second period T2. Since the control unit 4 performs control so as to compensate for the difference between theta and theta _e, an increase in the difference between theta and theta _e is, gamma reduction of the minimum value of the axial current i _gamma (the maximum value of the negative direction It appears as an increase in absolute value) (see FIG. 4).

_{By detecting a decrease in the minimum value of the γ-axis current i γ} (excitation current), the movement detection unit 49 detects a steep movement of the housing 9 or a sign thereof due to an increase in the load applied to the rotating shaft 16. doing. _{Specifically, the movement detection unit 49 indicates that the minimum value of the exciting current (γ-axis current i γ} ) has decreased (increased when viewed in absolute value) from the value immediately after the start of the striking operation. By detecting, a steep movement of the housing 9 or a sign thereof is detected. For example, when the movement detection unit 49 detects that the minimum value of the exciting current per unit time is equal to or less than a predetermined threshold value, it may determine that a steep movement has occurred or a sign thereof has occurred in the housing 9. Good.

In this way, the movement detection unit 49 detects a steep movement of the housing 9 with respect to the work target 100 or a sign thereof, based on at least one of the torque current and the exciting current supplied to the motor 15. The movement detection unit 49 may detect a steep movement of the housing 9 or a sign thereof based on the logical sum of the detection result based on the exciting current and the detection result based on the torque current, or the housing 9 based on the logical product. 9 steep movements or signs thereof may be detected.

When the control unit 4 detects a steep movement of the housing 9 or a sign thereof, the control unit 4 executes a protective operation. Here, the control unit 4 stops the motor 15 as a protective operation. The control unit 4, for example, the target value of the driving voltage _{V a} applied to inverter circuit 51 (voltage ^{_{value) v u *, v v *}} , v a ^{w *} With 0, stops the motor 15. As a result, when the housing 9 has a steep movement or a sign thereof, the rotation of the motor 15 which causes the sudden movement is stopped, so that the load applied to the user from the power tool 1 is reduced. Therefore, according to the power tool 1 of the present embodiment, it is possible to improve the usability.

(3) Modified Example The embodiment of the present disclosure is not limited to the above embodiment. The above-described embodiment can be variously modified depending on the design and the like as long as the object of the present disclosure can be achieved. Examples of modifications of the above embodiment are listed below.

The same function as the control unit 4 of the power tool 1 may be embodied by a control method of the power tool 1, a (computer) program, a non-temporary recording medium on which the program is recorded, or the like.

The control method of the power tool 1 according to one aspect includes controlling the rotational operation of the motor 15 in response to an operation on the operation unit 29 by using vector control. Further, the control method includes detecting a steep movement of the housing 9 with respect to the work target 100 or a sign thereof based on at least one of the torque current and the exciting current supplied to the motor 15.

Specifically, as shown in FIG. 5, when the operation unit 29 is operated, the control unit 4 uses the command value ω ₂ ^* set according to the amount of operation to the operation unit 29 to drive the motor 15. Vector control (ST1). Further, the control unit 4 determines whether or not there is a steep movement of the housing 9 or a sign thereof based on the torque current while the motor 15 is vector-controlled (ST2), and the steepness of the housing 9 is determined based on the exciting current. The presence or absence of movement or its sign is determined (ST3). When the control unit 4 detects a steep movement of the housing 9 or a sign thereof based on one or both of the torque current and the exciting current (ST4: Yes), the control unit 4 stops the motor 15 as a protective operation (ST5).

Note that FIG. 5 is an example of the control method of the present embodiment, and it is not always necessary to execute the process according to the flowchart of FIG. For example, step ST2 and step ST3 may be executed in the reverse order or may be executed at the same time.

The program according to one aspect is a program for causing one or more processors to execute the control method of the power tool 1 described above.

The execution subject of the control unit 4 described above includes a computer system. The main configuration of a computer system is a processor and memory as hardware. When the processor executes the program recorded in the memory of the computer system, a part of the function as the control unit 4 in the present disclosure is realized. The program may be pre-recorded in the memory of the computer system, may be provided through a telecommunications line, and may be recorded on a non-temporary recording medium such as a memory card, optical disk, hard disk drive, etc. that can be read by the computer system. May be provided. A processor in a computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The integrated circuit such as IC or LSI referred to here has a different name depending on the degree of integration, and includes an integrated circuit called a system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). Further, an FPGA (Field-Programmable Gate Array) programmed after the LSI is manufactured, or a logical device capable of reconfiguring the junction relationship inside the LSI or reconfiguring the circuit partition inside the LSI should also be adopted as a processor. Can be done. A plurality of electronic circuits may be integrated on one chip, or may be distributed on a plurality of chips. The plurality of chips may be integrated in one device, or may be distributed in a plurality of devices. The computer system referred to here includes a microprocessor having one or more processors and one or more memories. Therefore, the microprocessor is also composed of one or a plurality of electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

Further, it is not an essential configuration that a plurality of functions of the control unit 4 are integrated in one housing. The components of the control unit 4 may be dispersedly provided in a plurality of housings. On the contrary, a plurality of functions in the control unit 4 may be integrated in one housing as in the basic example. Further, at least a part of the functions of the control unit 4, for example, a part of the functions of the control unit 4 may be realized by a cloud (cloud computing) or the like.

(3-1) Modification 1
Hereinafter, the power tool 1 according to the modification 1 will be described. In the power tool 1 of this modified example, the same reference numerals are given to the same configurations as those of the embodiment, and the description thereof will be omitted.

The power tool 1 of this modification is, for example, a hammer drill. In the power tool 1 of this modification, the steep movement of the housing 9 detected by the movement detection unit 49 causes a sharp decrease in the load applied to the tip tool 28 (output shaft 21) from the work target 100 (loss of load). Includes movement of the housing 9 due to. The sign of steep movement of the housing 9 detected by the movement detection unit 49 is a sudden decrease in the load applied to the output shaft 21 from the work target 100 (loss of load), resulting in a sudden acceleration applied to the housing 9. Including increase.

For example, when a drill bit is used as the tip tool 28 to drill a hole in wood (work target 100), the bit may penetrate the wood. In this case, the load received from the wood is sharply reduced, so that the housing 9 may suddenly move forward together with the tip tool 28 (the steep movement of the housing 9).

The movement detection unit 49 of the control unit 4 of the power tool 1 of the present modification detects such a steep movement of the housing 9 or a sign thereof based on at least one of the torque current and the exciting current, here both. ..

Hereinafter, the operation of the power tool 1 of this modified example will be briefly described.

When drilling a hole in wood (work target 100) with the power tool 1 of this modified example, the speed ω of the motor 15 before the drill bit penetrates the wood, the δ-axis current i _δ (torque current), and the γ-axis. The outline of the current i _γ (exciting current) is the same as that of the first period T1 and the second period T2 of the embodiment.

On the other hand, when the drill bit penetrates the wood, the load applied to the output shaft 21 is reduced and the load applied to the rotating shaft 16 of the motor 15 is reduced as compared with before the drill bit penetrates the wood.

Therefore, in the period after the drill bit penetrates the wood (hereinafter, referred to as “post-penetration period”), the δ-axis current i _δ (torque current) decreases as the load applied to the rotating shaft 16 decreases. That is, the steep movement of the housing 9 due to the completion of drilling the work target 100 is the opposite of the steep movement of the housing 9 due to the reaction force from the work target 100 (see the embodiment), and is the current of the torque current. Appears as a decrease in the maximum, minimum, and average values of the values. _{By detecting the decrease in the δ-axis current i δ} (torque current), the movement detection unit 49 detects a steep movement of the housing 9 or a sign thereof due to a decrease in the load applied to the output shaft 21.

Further, in the post-penetration period, _{the difference between θ and θ e} that occurs while the hammer 19 retracts is smaller than that before the drill bit penetrates the wood. Therefore, in the post-penetration period, _{the minimum value of the measured value of the γ-axis current i γ} increases (the absolute value of the maximum value in the negative direction decreases; it approaches zero). _{By detecting an increase in the minimum value of the γ-axis current i γ} (excitation current), the movement detection unit 49 detects a steep movement of the housing 9 or a sign thereof due to a decrease in the load applied to the output shaft 21. ..

In this way, the movement detection unit 49 detects a steep movement of the housing 9 with respect to the work target 100 or a sign thereof, based on at least one of the torque current and the exciting current supplied to the motor 15. The movement detection unit 49 may detect a steep movement of the housing 9 or a sign thereof based on the logical sum of the detection result based on the exciting current and the detection result based on the torque current, or the housing 9 based on the logical product. 9 steep movements or signs thereof may be detected.

Even with the power tool 1 of this modified example, it is possible to take measures such as stopping the motor 15 in response to the sudden movement of the housing 9 or the detection of a sign thereof, and the usability of the power tool 1 can be improved.

The power tool 1 may have both the detection function of the present modification and the detection function of the above embodiment.

(3-2) Modification 2
Hereinafter, the power tool 1 according to the second modification will be described. In the power tool 1 of this modified example, the same reference numerals are given to the same configurations as those of the embodiment, and the description thereof will be omitted.

The power tool 1 of this modification is different from the power tool 1 of the embodiment in that the transmission mechanism 18 does not include the impact mechanism 17, for example, the drive shaft 22 and the output shaft 21 are integrally connected. .. The power tool 1 of this modification is, for example, a drill driver.

Hereinafter, the operation of the power tool 1 of this modified example will be briefly described.

_{Outline of speed ω of motor 15, δ-axis current i δ} (torque current), and γ-axis current i _γ (excitation current) when screw tightening work is performed using the power tool 1 of this modified example as a drill driver. Is similar to those of the first period T1 of the embodiment. _{Further, the outline of the speed ω, the δ-axis current i δ} , and the γ-axis current i _γ of the motor 15 after the load applied to the output shaft 21 is increased is the same as that of the third period T3 of the embodiment. That is, when the screw tightening work is performed using the electric tool 1 (drill driver) of this modified example, _{the outline of the speed ω, the δ-axis current i δ} , and the γ-axis current i _γ of the motor 15 is as follows in the second period T2. It is similar to those of the embodiment except that there is none.

Further, when drilling is performed using the electric tool 1 of this modified example, _{the outlines of the speed ω of the motor 15, the δ-axis current i δ} , and the γ-axis current i _γ are as follows, except that there is no second period T2. , The same as described in the first modification.

Therefore, even in the power tool 1 of the present modification, the control unit 4 (movement detection unit 49) has a steep housing 9 with respect to the work target 100 based on at least one of the torque current and the exciting current supplied to the motor 15. Movement or its signs can be detected.

_{Depending on the work target 100, the current value of the δ-axis current i δ and} the current value of the γ-axis current i _γ may not oscillate in the third period T3 (or the period after penetration).

(3-3) Other Modifications In one modification, the control unit 4 may stop the motor 15 _{as a protective operation by setting the command value ω 2} ^{* generated by the command value generation unit 48 to 0.} ..

In one modification, the control unit 4 of the power tool 1 may reduce the rotation speed of the motor 15 as a protective operation.

In one modification, the control unit 4 may block the transmission of the rotational force of the rotating shaft 16 of the motor 15 to the tip tool 28 as a protective operation. For example, when the transmission mechanism 18 includes a clutch mechanism, the clutch mechanism may block the transmission of the rotational force of the rotating shaft 16 of the motor 15 to the tip tool 28. The clutch mechanism may be realized by, for example, an electronic clutch.

In one modification, when the transmission mechanism 18 (for example, the planetary gear mechanism 25) includes a transmission mechanism, the control unit 4 performs the ratio of the speed of the tip tool 28 to the speed of the rotation shaft 16 of the motor 15 as a protective operation ( The reduction ratio) may be reduced.

In one modification, the power tool 1 may be an electric saw provided with a circular saw blade as the tip tool 28.

In one modification, the power tool 1 may be an electric hydraulic tool (oil pulse impact tool or the like).

In one modification, the power tool 1 may include an acceleration sensor or a gyro sensor that detects a steep movement of the housing 9 or a sign thereof. The control unit 4 may further refer to the detection result of the sensor and detect a steep movement of the housing 9 or a sign thereof.

In one modification, the power tool 1 may include a switching unit for switching between enabling and disabling the detection function. The switching unit may include, for example, a switch that accepts a user's operation. The detection function is enabled or disabled according to the operation of the switch.

In one modification, when the speed ω of the motor 15 is equal to or less than a predetermined speed threshold value, the control unit 4 may invalidate at least one of the detection function and the protection operation.

In one modification, the control unit 4 may include a storage unit that stores the history of the protection operation. The control unit 4 may be configured not to perform the protection operation when, for example, a steep movement of the housing 9 or a sign thereof is detected within a predetermined time after the protection operation is executed. For example, when the steep movement of the housing 9 or its sign is detected once and the motor 15 is stopped (protection operation is executed), and then the steep movement of the housing 9 or its sign is detected again within a predetermined time, the control unit 4 maintains the rotational operation of the motor 15 without stopping the motor 15. As a result, work efficiency can be improved.

(4) Aspects The following aspects are disclosed from the embodiments and modifications described above.

The power tool (1) of the first aspect includes a motor (15), an operation unit (29), a control unit (4), a transmission mechanism (18), and a housing (9). The operation unit (29) receives an operation from the user. The control unit (4) uses vector control to control the rotational operation of the motor (15) in response to an operation on the operation unit (29). The transmission mechanism (18) transmits the rotational force of the rotating shaft (16) of the motor (15) to the tip tool (28) that performs the work on the work target (100). The housing (9) houses at least the motor (15) and the transmission mechanism (18). The control unit (4) has a detection function that detects a steep movement of the housing (9) with respect to the work target (100) or a sign thereof based on at least one of the torque current and the exciting current supplied to the motor (15). Has.

According to this aspect, it is possible to take measures such as stopping the motor (15) in response to the sudden movement of the housing (9) or the detection of a sign thereof, and the usability of the power tool (1) can be improved. ..

In the power tool (1) of the second aspect, in the first aspect, the control unit (4) has a detection function in which the load applied to the rotating shaft (16) obtained based on the torque current is equal to or more than a predetermined value. Then, it is determined that there is a steep movement of the housing (9) or a sign thereof.

According to this aspect, a steep movement of the housing (9) due to an increase in the load applied to the rotating shaft (16) or a sign thereof can be detected.

In the power tool (1) of the third aspect, in the first or second aspect, the steep movement of the housing (9) includes the movement of the housing (9) due to the reaction force from the work object (100).

According to this aspect, the steep movement of the housing (9) due to the reaction force from the work object (100) can be detected.

In the power tool (1) of the fourth aspect, in any one of the first to third aspects, when the control unit (4) detects a steep movement of the housing (9) or a sign thereof, the motor (15) ) Is reduced or the motor (15) is stopped.

According to this aspect, when the housing (9) has a steep movement or a sign thereof, the motor (15) which causes the sudden movement is stopped or decelerated, so that the power tool (1) is applied to the user. The load is reduced. Therefore, the usability of the power tool (1) is improved.

In the power tool (1) of the fifth aspect, in any one of the first to fourth aspects, when the control unit (4) detects a steep movement of the housing (9) or a sign thereof, the motor (15) ) Is blocked from transmitting the rotational force of the rotating shaft (16) to the tip tool (28).

According to this aspect, when the housing (9) has a steep movement or a sign thereof, the rotation of the output shaft (21) which causes the sudden movement is stopped, so that the power tool (1) tells the user. The load is reduced. Therefore, the usability of the power tool (1) is improved.

The power tool (1) of the sixth aspect includes an output shaft (21) to which the tip tool (28) is connected in any one of the first to fifth aspects. The transmission mechanism (18) has an impact mechanism (17) that performs a striking operation that applies a striking force to the output shaft (21) according to the magnitude of torque applied to the output shaft (21).

According to this aspect, the usability of the so-called impact tool provided with the impact mechanism (17) can be improved.

The power tool (1) of the seventh aspect includes a switching unit for switching between valid and invalid of the detection function in any one of the first to sixth aspects.

According to this aspect, when the detection function is unnecessary, the function can be disabled and the usability of the power tool (1) can be improved.

The control method of the ninth aspect is a power tool control method. The power tool (1) includes a motor (15), an operation unit (29), a transmission mechanism (18), and a housing (9). The operation unit (29) receives an operation from the user. The transmission mechanism (18) transmits the rotational force of the rotating shaft (16) of the motor (15) to the tip tool (28) that performs the work on the work target (100). The housing (9) houses at least the motor (15) and the transmission mechanism (18). The control method includes controlling the rotational operation of the motor (15) in response to an operation on the operation unit (29) by using vector control. The control method includes detecting a steep movement of the housing (9) with respect to the work object (100) or a sign thereof, based on at least one of a torque current and an exciting current supplied to the motor (15).

According to this aspect, it is possible to take measures such as stopping the motor (15) in response to the sudden movement of the housing (9) or the detection of a sign thereof, and the usability of the power tool (1) can be improved. ..

The program of the ninth aspect is a program for causing one or more processors to execute the control method of the eighth aspect.

According to this aspect, it is possible to take measures such as stopping the motor (15) according to the detection of the steep movement of the housing (9) or the sign thereof, and the usability of the power tool (1) can be improved. ..

1 Power tool 4 Control unit 9 Housing 15 Motor 16 Rotating shaft 17 Impact mechanism 18 Transmission mechanism 21 Output shaft 28 Tip tool 29 Operation unit 100 Work target

Claims (9)

With the motor
An operation unit that accepts operations from users,
A control unit that controls the rotational operation of the motor in response to an operation on the operation unit using vector control.
A transmission mechanism that transmits the rotational force of the rotating shaft of the motor to the tip tool that performs work on the work object, and
A housing that houses at least the motor and the transmission mechanism,
With
The control unit has a detection function for detecting a steep movement of the housing with respect to the work target or a sign thereof based on at least one of a torque current and an exciting current supplied to the motor.
Electric tool. In the detection function, the control unit determines that there is a steep movement of the housing or a sign thereof when the load applied to the rotating shaft obtained based on the torque current becomes a predetermined value or more.
The power tool according to claim 1. The steep movement of the housing includes the movement of the housing due to a reaction force from the work object.
The power tool according to claim 1 or 2. When the control unit detects a steep movement of the housing or a sign thereof, the control unit reduces the speed of the motor or stops the motor.
The power tool according to any one of claims 1 to 3. When the control unit detects a steep movement of the housing or a sign thereof, it blocks the transmission of the rotational force of the rotary shaft of the motor to the tip tool.
The power tool according to any one of claims 1 to 4. The power tool includes an output shaft to which the tip tool is connected.
The transmission mechanism has an impact mechanism that performs a striking operation that applies a striking force to the output shaft according to the magnitude of torque applied to the output shaft.
The power tool according to any one of claims 1 to 5. A switching unit for switching between enabling and disabling the detection function is provided.
The power tool according to any one of claims 1 to 6. It is a control method for power tools.
The power tool
With the motor
An operation unit that accepts operations from users,
A transmission mechanism that transmits the rotational force of the rotating shaft of the motor to the tip tool that performs work on the work object, and
A housing that houses at least the motor and the transmission mechanism,
With
The control method is
Using vector control to control the rotational operation of the motor in response to an operation on the operation unit,
To detect a steep movement of the housing with respect to the work object or a sign thereof based on at least one of a torque current and an exciting current supplied to the motor.
including,
Control method. A program for causing one or more processors to execute the control method according to claim 8.

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