JP2021079471A - Electric power tool, come-out detection method and program - Google Patents

Abstract

To provide an electric power tool, a come-out detection method and a program which can detect come-out or a sign of come-out.SOLUTION: An electric power tool 1 comprises a motor 15, a control part 4, an output shaft, a transmission mechanism and a come-out detection part 54. The control part 4 vector-controls the motor 15. The output shaft is connected to a tip tool. The transmission mechanism transmits power of the motor 15 to the output shaft. The come-out detection part 54 detects come-out or a sign of come-out on the basis of a physical quantity intercorrelating with amplitude of excitation currents (a current measured value id1) that are supplied to the motor 15. The come-out is a phenomenon that fitting of the tip tool to a screw of a work object to be worked by the tip tool is released during operation of the motor 15.SELECTED DRAWING: Figure 1

Description

The present disclosure generally relates to power tools, come-out detection methods and programs, and more specifically, power tools including vector-controlled motors, come-out detection methods executed for the power tools, and execution of the come-out detection methods. Regarding the program to do.

The impact tool (electric tool) described in Patent Document 1 includes a motor, a drive shaft, an output shaft, and a socket (tip tool). The rotation of the motor is transmitted to the output shaft via the drive shaft. The output shaft is connected to the socket. The socket is provided with a square hole for fitting a head or a nut of a bolt (screw) which is a member to be tightened.

Japanese Unexamined Patent Publication No. 2015-193062

In a power tool such as an impact tool described in Patent Document 1, a come-out, which is a phenomenon in which a tip tool such as a socket is disengaged from a screw such as a bolt, may occur during the operation of the power tool.

It is an object of the present disclosure to provide a power tool, a come-out detection method and a program capable of detecting a come-out or a sign of a come-out.

The power tool according to one aspect of the present disclosure includes a motor, a control unit, an output shaft, a transmission mechanism, and a come-out detection unit. The control unit vector-controls the motor. The output shaft is connected to the tip tool. The transmission mechanism transmits the power of the motor to the output shaft. The come-out detection unit detects a come-out or a sign of the come-out based on a physical quantity that correlates with the amplitude of the exciting current supplied to the motor. The come-out is a phenomenon in which the tip tool and the screw to be worked by the tip tool are released from being fitted during the operation of the motor.

The come-out detection method according to one aspect of the present disclosure is a come-out detection method executed for an electric tool including a motor, a control unit, an output shaft, and a transmission mechanism. The control unit vector-controls the motor. The output shaft is connected to the tip tool. The transmission mechanism transmits the power of the motor to the output shaft. The come-out detection method detects a come-out or a sign of the come-out based on a physical quantity that correlates with the amplitude of the exciting current supplied to the motor. The come-out is a phenomenon in which the tip tool and the screw to be worked by the tip tool are released from being fitted during the operation of the motor.

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

The present disclosure has the advantage of being able to detect a come-out or a sign of a come-out.

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 cross-sectional view of a screw that is a work target of the same power tool. FIG. 5 is a graph showing an operation example of the same power tool. FIG. 6 is a graph showing another operation example of the same power tool. FIG. 7 is a flowchart showing a come-out detection method in 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 The power tool 1 of the present embodiment is an impact tool. The power tool 1 (see FIG. 2) is used as, for example, an impact driver, a hammer drill, an impact drill, an impact drill driver, or an impact wrench. In the present embodiment, as a typical example, a case where the power tool 1 is used as an impact driver for screwing a screw will be described. As shown in FIGS. 1 and 2, the power tool 1 includes a motor 15, a control unit 4, an output shaft 21, a transmission mechanism 18, and a come-out detection unit 54. The control unit 4 vector-controls the motor 15. The output shaft 21 is connected to the tip tool 28. The transmission mechanism 18 transmits the power of the motor 15 to the output shaft 21. The come-out detection unit 54 detects a come-out or a sign of come-out based on a physical quantity that correlates with the amplitude of the exciting current (current measurement value id1) supplied to the motor 15. The come-out is a phenomenon in which the tip tool 28 and the screw (tightening member 30) to be worked by the tip tool 28 are released from being fitted during the operation of the motor 15.

According to the power tool 1 of the present embodiment, it is possible to detect a come-out or a sign of a come-out. Therefore, it is possible to take measures according to the detection of the come-out or the sign of the come-out, automatically or by the operation of the operator.

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.

Vector control decomposes the current supplied to the coil 141 of the motor 15 into a current component (exciting current) that generates magnetic flux and a current component (torque current) that generates torque (rotational force), and each current component. It is a kind of motor control method that controls independently.

The current measurement value id1 is used for both vector control and detection of come-out or a sign of come-out. Therefore, a part of the circuit for vector control and a part of the circuit for detecting the come-out or the sign of the come-out can be shared. As a result, the area and dimensions of the circuit provided in the power tool 1 can be reduced, and the cost required for the circuit can be reduced.

(2) Power tool As shown in FIG. 2, the power tool 1 includes a power supply unit 32, a motor 15, a motor rotation measuring unit 27, a transmission mechanism 18, an output shaft 21, a socket 23, and a tip tool 28. And have. Further, the power tool 1 includes a trigger switch 29 and a control unit 4. The control unit 4 has a striking detection unit 49 that detects the presence or absence of a striking motion of the impact mechanism 17.

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. 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. The tip tool 28 (also referred to as a bit) is, for example, a driver bit, a drill bit, or the like. 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 power 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. Hereinafter, a case where the screw is tightened by the power tool 1 will be described. The type of screw is not particularly limited and may be, for example, a bolt, a screw or a nut. As shown in FIG. 2, the tightening member 30 of this embodiment is a wood screw. The tightening member 30 has a head portion 301, a cylindrical portion 302, and a screw portion 303. The head 301 is connected to the first end of the cylindrical portion 302. A screw portion 303 is connected to the second end of the cylindrical portion 302. The head 301 is formed with a screw hole 310 (see FIG. 4) that fits the tip tool 28. The screw hole 310 is, for example, a + -shaped hole. A thread is formed in the threaded portion 303.

The tip tool 28 fits with the tightening member 30. That is, the tip tool 28 is inserted into the screw hole 310 of the head 301 of the tightening member 30. In this state, the tip tool 28 is driven by the motor 15 to rotate, and rotates the tightening member 30. As a result, the tightening member 30 (wood screw) is embedded in the member to be screwed while forming a hole and a screw groove in the member to be screwed (for example, a wall material). That is, the tip tool 28 applies a tightening force (or a loosening force) to the tightening member 30.

In the present embodiment, the tip tool 28 and the tightening member 30 are fitted by pointing to a state in which at least a part of the tip portion 280 of the tip tool 28 is inserted into the screw hole 310 (see FIG. 4) of the tightening member 30. Say it fits. Further, it indicates that the tip portion 280 of the tip tool 28 goes out of the screw hole 310 from the state where the tip tool 28 and the tightening member 30 are fitted during the operation (rotation) of the motor 15. It is said that a phenomenon in which the tip tool 28 and the tightening member 30 are disengaged, that is, a come-out occurs. Then, when the tip portion 280 is in the screw hole 310 and it is predicted that a come-out will occur from now on, it is said that there is a sign of a come-out.

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 transmission mechanism 18 includes a planetary gear mechanism 25, a drive shaft 22, and an impact mechanism 17. 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. Further, the impact mechanism 17 performs a striking operation of applying a striking force to the output shaft 21.

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 a load (torque) of a predetermined magnitude or more is not applied to the output shaft 21, 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.

On the other hand, when a load of a predetermined size or more 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 (that is, separates 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 (that is, moves toward the output shaft 21) and applies a striking force in the rotational direction to the anvil 20. , Rotate the output 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. While the hammer 19 moves forward and backward once, a striking force is generated once.

The trigger switch 29 is an operation unit that receives an operation for controlling the rotation of the motor 15. The motor 15 can be switched on and off by pulling the trigger switch 29. Further, the rotation speed of the motor 15 can be adjusted by the pull-in amount of the operation of pulling the trigger switch 29. 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 29. 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 29, 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 29.

The motor rotation measuring unit 27 measures the rotation angle of the motor 15. As the motor rotation measuring unit 27, for example, a photoelectric encoder or a magnetic encoder can be adopted.

The power tool 1 includes an inverter circuit unit 51 (see FIG. 1). The inverter circuit unit 51 supplies a current to the motor 15. The control unit 4 is used together with the inverter circuit unit 51, and controls the operation of the motor 15 by feedback control.

(3) Control unit 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 command value generation unit 41, a speed control unit 42, a current control unit 43, a first coordinate converter 44, a second coordinate converter 45, and a magnetic flux. It has a control unit 46, an estimation unit 47, a step-out detection unit 48, a hit detection unit 49, a come-out detection unit 54, and a notification unit 55. 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 and 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 (see FIG. 2) to the motor 15 via the inverter circuit unit 51. Here, a three-phase current (U-phase current, V-phase current, and W-phase current) is supplied to the motor 15, and the plurality of current sensors 61 and 62 measure at least two-phase currents. In FIG. 1, the current sensor 61 measures the U-phase current and _{outputs the measured current value i u} 1, and the current sensor 62 measures the V-phase current and outputs the _{measured current value i v 1.}

The estimation unit 47 calculates the angular velocity ω1 (angular velocity of the rotation shaft 16) of the motor 15 by time-differentiating the rotation angle θ1 of the motor 15 measured by the motor rotation measurement unit 27.

The acquisition unit 60 has two current sensors 61 and 62 and a second coordinate converter 45. The acquisition unit 60 acquires the d-axis current (excitation current) and the q-axis current (torque current) supplied to the motor 15. That is, the two-phase currents measured by the two current sensors 61 and 62 are converted by the second coordinate converter 45, so that the current measurement value id1 of the d-axis current and the current measurement value iq1 of the q-axis current are obtained. Calculated.

The second coordinate converter 45 uses the current measured values i _u 1 and i _v 1 measured by the plurality of current sensors 61 and 62 based on the rotation angle θ1 of the motor 15 measured by the motor rotation measuring unit 27. The coordinates are converted and the current measurement values id1 and iq1 are calculated. That is, the second coordinate converter 45, a current measurement value _i u 1, _{i v} 1 corresponding to the three-phase current, a current measurement value id1 corresponding to the magnetic field component (d-axis current), the torque component (q-axis It is converted to the current measured value iq1 corresponding to the current).

The command value generation unit 41 generates the command value cω1 of the angular velocity of the motor 15. The command value generation unit 41 generates, for example, the command value cω1 according to the pull-in amount of the operation of pulling the trigger switch 29 (see FIG. 2). That is, the command value generation unit 41 increases the command value cω1 of the angular velocity as the pull-in amount increases.

The speed control unit 42 generates the command value ciq1 based on the difference between the command value cω1 generated by the command value generation unit 41 and the angular velocity ω1 calculated by the estimation unit 47. The command value ciq1 is a command value that specifies the magnitude of the torque current (q-axis current) of the motor 15. The speed control unit 42 determines the command value ciq1 so as to reduce the difference between the command value cω1 and the angular velocity ω1.

The magnetic flux control unit 46 generates a command value cid1 based on the angular velocity ω1 calculated by the estimation unit 47, the command value cvq1 (described later) generated by the current control unit 43, and the current measurement value iq1. .. The command value cid1 is a command value that specifies the magnitude of the exciting current (d-axis current) of the motor 15. That is, the control unit 4 controls the operation of the motor 15 so that the exciting current (d-axis current) supplied to the coil 141 of the motor 15 approaches the command value cid1.

In the present embodiment, the command value cid1 generated by the magnetic flux control unit 46 is a command value for setting the magnitude of the exciting current to 0. However, the magnetic flux control unit 46 may generate a command value cid1 for constantly setting the magnitude of the exciting current to 0, or, if necessary, to make the magnitude of the exciting current larger or smaller than 0. The command value cid1 of may be generated. When the command value cid1 of the exciting current becomes smaller than 0, a negative exciting current (weak magnetic flux current) flows through the motor 15.

The current control unit 43 generates the command value cvd1 based on the difference between the command value cid1 generated by the magnetic flux control unit 46 and the current measurement value id1 calculated by the second coordinate converter 45. The command value cvd1 is a command value that specifies the magnitude of the d-axis voltage of the motor 15. The current control unit 43 determines the command value cvd1 so as to reduce the difference between the command value cid1 and the current measurement value id1.

Further, the current control unit 43 generates the command value cvq1 based on the difference between the command value iq1 generated by the speed control unit 42 and the current measurement value iq1 calculated by the second coordinate converter 45. The command value cvq1 is a command value that specifies the magnitude of the q-axis voltage of the motor 15. The current control unit 43 generates the command value cvq1 so as to reduce the difference between the command value xiq1 and the current measurement value iq1.

The first coordinate converter 44 converts the command values cvd1 and cvq1 into coordinates based on the rotation angle θ1 of the motor 15 measured by the motor rotation measuring unit 27, and converts the command values cv _u 1, cv _v 1, and cv _w. 1 is calculated. That is, the first coordinate converter 44 sets the command value cvd1 corresponding to the magnetic field component (d-axis voltage) and the command value cvq1 corresponding to the torque component (q-axis voltage) to the command value corresponding to the three-phase voltage. Convert to cv _u 1, cv _v 1, cv _{w 1.} The command value cv _u 1 corresponds to the U-phase voltage, the command value cv _v 1 corresponds to the V-phase voltage, and the command value cv _w 1 corresponds to the W-phase voltage.

The control unit 4 controls the electric power supplied to the motor 15 by controlling the inverter circuit unit 51 by PWM (Pulse Width Modulation). As a result, the inverter circuit unit 51 supplies the motor 15 with a three-phase voltage according to _{the command values cv u} 1, cv _v 1, and cv _{w 1.}

The motor 15 is driven by electric power (three-phase voltage) supplied from the inverter circuit unit 51 to generate rotational power.

As a result, the control unit 4 controls the exciting current so that the exciting current flowing through the coil 141 of the motor 15 has a magnitude corresponding to the command value cid1 generated by the magnetic flux control unit 46. Further, the control unit 4 controls the angular velocity of the motor 15 so that the angular velocity of the motor 15 becomes the angular velocity corresponding to the command value cω1 generated by the command value generation unit 41.

The step-out detection unit 48 detects the step-out of the motor 15 based on the current measurement values id1 and iq1 acquired from the second coordinate converter 45 and the command values cvd1 and cvq1 acquired from the current control unit 43. To do. When step-out is detected, the step-out detection unit 48 transmits a stop signal cs1 to the inverter circuit unit 51 to stop the power supply from the inverter circuit unit 51 to the motor 15.

The impact detection unit 49 detects the presence or absence of the impact operation of the impact mechanism 17. Details of the impact detection unit 49 will be described later.

(4) Details of Vector Control Hereinafter, vector control by the control unit 4 will be described in more detail. FIG. 3 is an analysis model diagram of 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 actual magnetic flux created by the permanent magnet 131 is the direction of the d-axis, and the coordinate axis corresponding to the control of the motor 15 by the control unit 4 and the coordinate axis corresponding to the d-axis is 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 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. The ω e in} FIG. 3 coincides with the ω 1 in FIG. 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. Θ e in} FIG. 3 coincides with θ 1 in FIG. The angle represented by θ and θ _e is an angle in the electric angle, and is also called a rotor position or a magnetic pole position. The rotation speed represented by ω and ω _e is the angular velocity at the electric angle.

When θ and θ _e coincide, the d-axis and q-axis coincide with the γ-axis and δ-axis, respectively. In vector control, the control unit 4 basically controls so that _{θ and θ e match.} Therefore, when the command value cid1 the d-axis current is zero, the load on the motor 15 is increased or decreased, the control unit 4, since the control to compensate for the difference between this way caused theta and theta _e , The current measurement value id1 of the d-axis current becomes a positive value or a negative value. Specifically, immediately after the load applied to the motor 15 becomes small, the current measured value id1 of the d-axis current becomes a positive value, and at the moment when the load applied to the motor 15 becomes large, the current measured value id1 becomes negative. It becomes a value.

(5) Impact detection The impact mechanism 17 performs a striking operation according to the magnitude of the torque applied to the output shaft 21. The impact detection unit 49 detects the presence or absence of a impact operation of the impact mechanism 17 based on at least one of the torque current and the exciting current supplied to the coil 141 of the motor 15. Hereinafter, an example of a method of detecting the presence or absence of a striking motion by the striking detection unit 49 will be described with reference to FIGS. 5 and 6. Since the force by which the user presses the tip tool 28 against the tightening member 30 is smaller in the case of FIG. 5 than in the case of FIG. 6, the behavior of the power tool 1 is different between FIGS. 5 and 6. In FIGS. 5 and 6, N1 is the rotation speed of the motor 15 (rotor 13), and cN1 is the command value of the rotation speed of the motor 15. That is, the command value cN1 is a value obtained by converting the command value cω1 of the angular velocity of the motor 15 into the rotation speed. Bd1 is a value obtained by plotting the maximum value (peak value) of the current measurement value id1 of the d-axis current per unit time for each unit time (for example, several milliseconds to several tens of milliseconds). Bd2 is a value obtained by plotting the minimum value of the current measurement value id1 of the d-axis current per unit time for each unit time (for example, several milliseconds to several tens of milliseconds). Here, Bd1 is a positive value and Bd2 is a negative value. Hereinafter, Bd1 is referred to as a positive d-axis current measurement value, and Bd2 is referred to as a negative d-axis current measurement value.

The positive d-axis current measurement value Bd1 and the negative d-axis current measurement value Bd2 are physical quantities that correlate with the amplitude of the d-axis current (excitation current). The physical quantity that correlates with the amplitude of the d-axis current includes the amplitude of the d-axis current itself and the physical quantity calculated from the amplitude of the d-axis current.

Here, the striking detection unit 49 detects the presence or absence of a striking operation based on both the current measurement values id1 and iq1. More specifically, with respect to the current measurement value id1, the impact detection unit 49 determines whether or not the following first condition is satisfied. The first condition is that the amplitude of the measured current value id1 is larger than the predetermined d-axis threshold value. The amplitude of the current measurement value id1 is defined as, for example, 1/2 of the difference between the maximum value and the minimum value of the current measurement value id1 per unit time. That is, the amplitude of the current measurement value id1 is defined as, for example, 1/2 of the difference between the maximum value of the positive d-axis current measurement value Bd1 and the minimum value of the negative d-axis current measurement value Bd2 per unit time. .. The impact detection unit 49 determines, for example, whether or not the first condition is satisfied for each unit time. The amplitude A1 illustrated in FIG. 5 is a current measurement defined by a current measurement value id1 at each time point from a certain time point t5 until a unit time (for example, several milliseconds to several tens of milliseconds) elapses. It is twice the amplitude of the value id1.

In this way, the impact detection unit 49 detects the presence or absence of the impact operation based on the amplitude of the current measurement value id1 (excitation current).

Further, regarding the current measurement value iq1, the impact detection unit 49 determines whether or not the following second condition is satisfied. The second condition is that the amount of decrease in the current measurement value iq1 per predetermined time (for example, several tens of milliseconds) is larger than the predetermined q-axis threshold value. The hit detection unit 49 determines, for example, whether or not the second condition is satisfied at each predetermined time.

In this way, the impact detection unit 49 detects the presence or absence of the impact operation based on the amount of decrease in the current measurement value iq1 (torque current) per predetermined time.

In the impact detection unit 49, for example, when the time required from the satisfaction of one of the first condition and the second condition to the satisfaction of the other is equal to or less than a predetermined time threshold value, the impact mechanism 17 performs a striking operation. Outputs the detection result that it is doing. In other cases, the impact detection unit 49 outputs a detection result that the impact mechanism 17 is not performing the impact operation.

That is, the load applied to the motor 15 increases and decreases from moment to moment, and when the striking operation starts, the amount of increase and decrease in the load applied to the motor 15 increases, so that the difference between θ and θe becomes large, and the current of the exciting current is measured. The amplitude of the value id1 increases. Further, when the striking operation is started, the load applied to the motor 15 is reduced while repeatedly increasing and decreasing, so that the current measured value iq1 of the torque current is reduced. The striking detection unit 49 detects the presence or absence of a striking motion by determining the presence or absence of such a change according to the first condition and the second condition.

The threshold values such as the d-axis threshold value and the q-axis threshold value are recorded in advance in the memory of the microcontroller constituting the control unit 4, for example.

The impact detection unit 49 starts detecting the presence or absence of the impact operation of the impact mechanism 17 after a predetermined mask period Tm1 has elapsed from the start of the motor 15 (at the start of rotation). Therefore, it is possible to prevent the impact detection unit 49 from erroneously detecting the impact operation during the mask period Tm1.

In FIG. 5, after the motor 15 starts operating at time t0, the impact mechanism 17 starts striking operation at time t1. After a little time has passed from the time point t1, the amplitude of the current measurement value id1 increases. Further, from the time point t1 to the time point t2, the measured current value iq1 decreases while repeatedly increasing and decreasing. Between time point t1 and time point t2, the second condition is met once or twice. The hitting detection unit 49 can detect the hitting motion based on the first condition and the second condition in at least a part of the period between the time point t1 and the time point t2.

In FIG. 6, similarly to FIG. 5, the impact mechanism 17 starts the striking operation at the time point t1 after the motor 15 starts the operation at the time point t0. At the time point t2 after the time point t1, the impact detection unit 49 outputs a detection result that the impact mechanism 17 is performing the impact operation.

In FIGS. 5 and 6, the work of tightening the tightening member 30 is completed at the time point t6. That is, the tightening member 30 is seated at the time point t6. Therefore, at the time point t6, the user stops the operation of pulling in the trigger switch 29. As a result, the command value cN1 drops to 0 [rpm], so that the rotation speed N1 becomes 0 [rpm]. That is, the motor 15 stops.

(6) Mechanism of Come-out The come-out will be described below with reference to FIG. First, a first example of a mechanism in which a come-out occurs in the power tool 1 will be described. When the rotation speed N1 of the motor 15 is unstable or the like, the hammer 19 advances to the front end within a movable range, and as a result, the pressing force from the tip tool 28 to the tightening member 30 momentarily increases. There is. After that, the reaction of the tightening member 30 to the tip tool 28 may cause the tip tool 28 to separate from the tightening member 30 and cause a come-out.

Next, a second example of the mechanism in which the come-out occurs in the power tool 1 will be described. A tapered surface 311 is provided in the screw hole 310 (see FIG. 4) of the tightening member 30, and when a force in a direction intersecting the axial direction of the tightening member 30 is applied from the tip tool 28 to the tapered surface 311, the tip The tool 28 may move out of the screw hole 310 along the tapered surface 311. That is, a come-out may occur. For example, since the direction of the tip tool 28 with respect to the tightening member 30 is oblique, the component of the force applied from the tip tool 28 to the tightening member 30 in the direction intersecting the axial direction of the tightening member 30 becomes relatively large. In some cases, the mechanism of the second example may cause a come-out. Further, when the pressing force from the tip tool 28 to the tightening member 30 is insufficient with respect to the rotation speed N1 of the motor 15, a come-out may occur by the mechanism of the second example.

A come-out can occur due to the mechanism described in the first example, the mechanism described in the second example, or both.

(7) Detection of Comeout or Its Sign Next, an example of the process in which the comeout detection unit 54 detects the comeout or its sign will be described with reference to FIGS. 5 and 6.

The come-out detection unit 54 detects a come-out or a sign of come-out based on a physical quantity that correlates with the amplitude of the exciting current (current measurement value id1) supplied to the motor 15. Here, the come-out detection unit 54 uses the positive peak value of the exciting current as a physical quantity that correlates with the amplitude of the exciting current. That is, the come-out detection unit 54 detects a come-out or a sign of a come-out based on the positive d-axis current measurement value Bd1.

More specifically, the come-out detection unit 54 detects a come-out or a sign of a come-out based on the fluctuation of the positive peak value of the exciting current. In other words, the come-out detection unit 54 detects a come-out or a sign of come-out based on the fluctuation of the positive d-axis current measurement value Bd1.

As an example, the come-out detection unit 54 sets a come-out threshold Th1 and compares the come-out threshold Th1 with the positive d-axis current measurement value Bd1 to detect a sign of come-out or come-out. More specifically, the come-out detection unit 54 indicates that a come-out has occurred or a sign of a come-out occurs when the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1 a predetermined number of times or more in a predetermined determination time. Judge that there is.

The force with which the user presses the tip tool 28 against the tightening member 30 is smaller in the case of FIG. 5 than in the case of FIG. Therefore, in FIG. 5, the tip tool 28 is easily separated from the inner surface of the screw hole 310 of the tightening member 30. In other words, in FIG. 5, the power tool 1 is in a state in which a come-out is likely to occur (there is a sign of a come-out). At the moment when the tip tool 28 separates from the inner surface of the screw hole 310, the load applied to the motor 15 becomes small, so that the current measured value id1 becomes a positive value and becomes large. That is, the positive d-axis current measured value Bd1 becomes large. Then, in a state where there is a sign of come-out, there is a high possibility that the event that the tip tool 28 separates from the inner surface of the screw hole 310 and the event that the tip tool 28 comes into contact with the inner surface are repeated. Therefore, the come-out detection unit 54 can detect a sign of come-out by monitoring the number of times that the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1.

Similarly, when a come-out occurs, the positive d-axis current measured value Bd1 becomes large before the come-out occurs, so that the positive d-axis current measured value Bd1 exceeds the come-out threshold Th1 in the come-out detection unit 54. Comeout can be detected by monitoring the number of times.

The come-out detection unit 54 of the present embodiment detects the come-out and the sign of the come-out without distinguishing them. That is, the condition that the come-out detection unit 54 detects the come-out and the condition that the come-out sign is detected are the same, and the come-out detection unit 54 determines whether the power tool 1 has a come-out or a come-out sign. , Outputs the same detection result.

The determination time is, for example, 200 [ms]. The predetermined number of times is, for example, 10 times. That is, in this example, the come-out detection unit 54 determines that a come-out has occurred or there is a sign of a come-out when the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1 10 times or more during 200 [ms]. To do.

In FIG. 5, in the time (determination time) between the time point t3 and the time point t4, the number of times that the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1 is 12 times. Therefore, at the time point t4, the come-out detection unit 54 determines that a come-out has occurred or there is a sign of a come-out.

In FIG. 6, the positive d-axis current measurement value Bd1 is smaller than that in FIG. In FIG. 6, the number of times that the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1 is less than 10 times in an arbitrary determination time after the time point t0. Therefore, the come-out detection unit 54 determines that the come-out has not occurred and there is no sign of the come-out.

By the way, the come-out threshold Th1 may have different values depending on whether the hitting detection unit 49 detects the hitting motion or not. When the striking detection unit 49 detects the striking motion, the positive d-axis current measured value Bd1 tends to be larger than when the striking motion is not detected. Therefore, the come-out threshold Th1 may be a value larger when the hitting detection unit 49 detects the hitting motion than when it is not.

The notification unit 55 of the power tool 1 notifies when the come-out detection unit 54 detects a come-out or a sign of a come-out. The notification unit 55 includes, for example, a light emitting unit such as a light emitting diode, and notifies the user by changing the light emitting state. Changing the light emitting state means, for example, switching between lighting and extinguishing, changing the brightness, changing the color of the light, and the like. Alternatively, the notification unit 55 is provided with, for example, a buzzer, a speaker, or the like, and notifies the user by sound (including voice). The voice notification is, for example, issuing the message "Please press the power tool strongly against the screw." Alternatively, the notification unit 55 is provided with, for example, a communication interface, and notifies the external device by transmitting a signal to the external device by wire communication or wireless communication.

When the sign of come-out is detected, the notification unit 55 notifies the user so that the sign of come-out can be known. Further, by notifying the notification unit 55 when the come-out is detected, the user can know that the come-out has occurred even in a situation where the tightening member 30 cannot be visually recognized.

(8) Come-out response function The control unit 4 has a come-out response function. In the come-out response function, when the come-out detection unit 54 detects a come-out or a sign of come-out, the control unit 4 lowers the rotation speed N1 of the motor 15 or stops the motor 15.

Further, the control unit 4 has a first mode for enabling the come-out response function and a second mode for disabling the come-out response function as operation modes that can be switched between each other. 5 and 6 are graphs when the operation mode of the control unit 4 is the second mode. However, the broken line portion cN2 in FIG. 5 shows the change in the command value cN1 after the time point t4 when the operation mode of the control unit 4 is the first mode.

When the operation mode of the control unit 4 is the first mode, in FIG. 5, at the time point t4, the come-out detection unit 54 detects a come-out or a sign of a come-out. Then, the control unit 4 reduces the rotation speed N1 of the motor 15 or stops the motor 15. Here, it will be described that the control unit 4 reduces the rotation speed N1 of the motor 15. That is, at the time point t4, the control unit 4 lowers the command value cN1 of the rotation speed N1 of the motor 15 as shown by the broken line portion cN2. As a result, the rotation speed N1 also decreases. For example, after the time when the come-out detection unit 54 detects a come-out or a sign of a come-out, the control unit 4 tentatively determines the command value cN1 according to the pull-in amount of the trigger switch 29, and then lowers the command value cN1. More specifically, the command value generation unit 41 of the control unit 4 substantially lowers the command value cN1 of the rotation speed N1 by lowering the command value cω1 of the angular velocity.

The control unit 4 may determine the rotation speed N1 after the decrease based on the rotation speed N1 before the decrease. For example, when the come-out detection unit 54 detects a come-out or a sign of come-out, the control unit 4 multiplies the command value cN1 at that time by a predetermined value (for example, 0.9) that is greater than 0 and less than 1. May be a new command value cN1. Further, when the come-out detection unit 54 detects a come-out or a sign of come-out, the control unit 4 subtracts a predetermined value (for example, 2000 [rpm]) from the command value cN1 at that time to obtain a new command value cN1. May be. However, the control unit 4 appropriately adjusts the above-mentioned predetermined value so that the command value cN1 becomes 0 or more.

By reducing the rotation speed N1 of the motor 15, the magnitude of the striking force in the striking operation of the impact mechanism 17 is reduced. As a result, the force applied from the tip tool 28 to the tightening member 30 is reduced. Further, the force (reaction force) acting on the tip tool 28 from the tightening member 30 in the direction of separating the tip tool 28 from the tightening member 30 is reduced. As a result, the possibility of a come-out can be reduced.

Further, as the rotation speed N1 of the motor 15 decreases, the interval at which the impact force is generated in the impact operation of the impact mechanism 17 (that is, the cycle of collision between the hammer 19 and the anvil 20) becomes longer, so that a come-out may occur. Can be reduced.

When the control unit 4 stops the motor 15 when a come-out or a sign thereof is detected, the user can take the following measures after the motor 15 is stopped. The user can reduce the possibility of come-out by pulling the trigger switch 29 again to start the motor 15 and pressing the tip tool 28 against the tightening member 30 more strongly. Further, the user can reduce the possibility of come-out by replacing the tip tool 28 with a tip tool of a type suitable for the tightening member 30. The notification unit 55 may notify the content of the measures that the user can take.

The power tool 1 is provided with, for example, a first user interface that accepts user operations. The first user interface is, for example, a button, a slide switch, a touch panel, or the like. Depending on the user's operation on the first user interface, the control unit 4 switches the operation mode between the first mode and the second mode. As an example, the user sets the operation mode of the control unit 4 to the first mode when tightening the screws using the power tool 1, and sets the operation mode to the second mode in other cases.

Further, the first user interface may have a display corresponding to come-out detection at a position corresponding to switching to the first mode. The display is, for example, characters such as "come-out detection mode" or "come-out prevention mode", or a figure, a picture, a photograph, or the like showing how a screw comes out. The above-mentioned display may be provided on the mechanical button for switching to the first mode or the button displayed on the screen of the touch panel, or the above-mentioned display may be provided in the vicinity of the button. Further, the above display may be provided near the position of the slide switch in the first mode.

(Modification example)
Hereinafter, modified examples of the embodiments are listed. The following modifications may be realized in appropriate combinations.

The same function as that of the power tool 1 may be realized by a come-out detection method, a (computer) program, a non-temporary recording medium on which the program is recorded, or the like.

The come-out detection method according to one aspect detects a come-out or a sign of a come-out based on a physical quantity that correlates with the amplitude of the exciting current supplied to the motor 15.

That is, as shown in FIG. 7, the come-out detection unit 54 acquires a positive d-axis current measurement value Bd1 (step ST1). Further, the come-out detection unit 54 determines whether or not the number of times the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1 in the determination time is equal to or greater than a predetermined number of times (step ST2). When the positive d-axis current measurement value Bd1 exceeds the come-out threshold Th1 a predetermined number of times or more in the determination time (step ST2: YES), the come-out detection unit 54 determines that a come-out has occurred or there is a sign of a come-out. Determine (step ST3). When the come-out detection unit 54 determines that a come-out has occurred or there is a sign of a come-out, the control unit 4 reduces the rotation speed N1 of the motor 15 (step ST4).

The program according to one aspect is a program for causing one or more processors to execute the above-mentioned come-out detection method.

The power tool 1 in the present disclosure 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 power tool 1 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 for the power tool 1 that a plurality of functions of the power tool 1 are integrated in one housing, and the components of the power tool 1 are distributed and provided in the plurality of housings. You may be. Further, at least a part of the functions of the power tool 1, for example, a part of the functions of the come-out detection unit 54 may be realized by a cloud (cloud computing) or the like.

The motor 15 may be an AC motor or a DC motor.

The tip tool 28 does not have to be included in the configuration of the power tool 1.

The tip tool 28 is not limited to the Phillips driver bit, and may be, for example, a minus driver bit, a Torx (registered trademark) bit, or a wrench bit.

The impact detection unit 49 may be provided separately from the control unit 4. That is, even if a configuration that realizes the function of the control unit 4 that vector-controls the motor 15 and a configuration that realizes the function of the impact detection unit 49 that detects the presence or absence of the impact operation of the impact mechanism 17 are separately provided. Good.

The come-out detection unit 54 may be provided separately from the control unit 4. That is, a configuration that realizes the function of the control unit 4 that vector-controls the motor 15 and a configuration that realizes the function of the come-out detection unit 54 that detects the come-out or a sign thereof may be separately provided.

Instead of the motor rotation measuring unit 27, an acceleration sensor that measures the angular acceleration or the circumferential acceleration of the rotating shaft 16 of the motor 15 may be used.

The impact detection unit 49 outputs a detection result that the impact mechanism 17 is performing an impact operation when at least one of the first condition regarding the current measurement value id1 and the second condition regarding the current measurement value iq1 is satisfied. May be good. Further, the batting detection unit 49 may determine the presence / absence of a striking motion based only on the first condition, or may determine the presence / absence of a striking motion based only on the second condition.

Further, the impact detection unit 49 may use a condition relating to the absolute value of the current measurement value iq1 as the second condition. For example, the impact detection unit 49 may make it a second condition that the absolute value of the current measured value iq1 (instantaneous value) exceeds a predetermined threshold value. Then, the impact detection unit 49 may output a detection result that the impact mechanism 17 is performing a striking operation, for example, when the first condition is satisfied after the second condition is satisfied. Alternatively, in the impact detection unit 49, for example, when the time required from the satisfaction of one of the first condition and the second condition to the satisfaction of the other is equal to or less than a predetermined time threshold value, the impact mechanism 17 strikes. You may output the detection result that it is operating.

The second condition is that the impact detection unit 49 requires that the absolute value of the current measured value iq1 exceeds a predetermined threshold value, and then the amount of decrease in the current measured value iq1 per predetermined time is larger than the predetermined q-axis threshold value. May be. Then, in the impact detection unit 49, for example, when the time required from the satisfaction of one of the first condition and the second condition to the satisfaction of the other is equal to or less than a predetermined time threshold value, the impact mechanism 17 strikes. You may output the detection result that it is operating.

In this way, the impact detection unit 49 determines the presence or absence of the impact operation based on at least one of the absolute value of the current measurement value iq1 (torque current) and the decrease amount of the current measurement value iq1 (torque current) per predetermined time. It may be detected.

Further, the impact detection unit 49 may detect the presence or absence of an impact operation based on the rotation speed N1 of the motor 15 in addition to at least one of the current measurement values id1 and iq1.

The impact detection unit 49 may detect the presence or absence of an impact operation based on the command value iq1 instead of the current measurement value iq1 of the torque current. That is, the current measurement value iq1 may be replaced with the command value iq1 in the detection of the presence or absence of the striking operation in the embodiment and each modification.

The impact detection unit 49 may detect the presence or absence of an impact operation based on at least one of a positive d-axis current measurement value Bd1 and a negative d-axis current measurement value Bd2 instead of the exciting current current measurement value id1. ..

The control unit 4 may have a function of changing the come-out threshold Th1. The power tool 1 may include, for example, a second user interface that accepts user operations. The second user interface is, for example, a button, a slide switch, a touch panel, or the like. The control unit 4 changes the come-out threshold Th1 according to the user's operation on the second user interface. Alternatively, the power tool 1 may include, for example, a receiving unit that receives a signal input. The receiving unit receives the above signal from the external device of the power tool 1, and the control unit 4 changes the come-out threshold Th1 accordingly. The communication method between the external device and the receiving unit may be wireless communication or wired communication. At least a part of the configuration may be shared between the second user interface and the first user interface.

Further, the control unit 4 may change the come-out threshold Th1 based on the current measurement value id1. For example, the control unit 4 obtains the maximum value of the positive d-axis current measurement value Bd1 within the determination time every predetermined determination time (for example, 200 [ms]), and determines the determined maximum value for the next determination time. The come-out threshold value Th1 used in the above may be set.

The come-out detection unit 54 may detect the come-out or a sign thereof based on the negative d-axis current measurement value Bd2 instead of the positive d-axis current measurement value Bd1. Further, the come-out detection unit 54 may detect the come-out or a sign thereof based on the positive d-axis current measurement value Bd1 and the negative d-axis current measurement value Bd2. Further, the come-out detection unit 54 may detect the come-out or a sign thereof based on the amplitude of the current measurement value id1 instead of the positive d-axis current measurement value Bd1 and the negative d-axis current measurement value Bd2. ..

Further, the come-out detection unit 54 may detect the come-out or a sign thereof based on the variation of the physical quantity that correlates with the amplitude of the current measurement value id1. The come-out detection unit 54 may determine that a come-out has occurred or is a sign thereof, for example, when the variation in the physical quantity that correlates with the amplitude of the current measurement value id1 within a predetermined determination time exceeds a predetermined value.

The come-out detection unit 54 may detect the come-out or a sign thereof based on the torque current (current measurement value iq1 or the like) in addition to the exciting current (positive d-axis current measurement value Bd1 or the like). In addition to the exciting current, the come-out detection unit 54 may detect the come-out or a sign thereof, for example, based on at least one of a physical quantity and a waveform pattern that correlate with the magnitude and amplitude of the torque current.

The come-out detection unit 54 of the embodiment detects the come-out and the sign of the come-out without distinguishing them, but the present invention is not limited to this, and the come-out and the sign of the come-out may be detected separately. When there is a sign of come-out, the tip tool 28 repeats the event of moving away from the inner surface of the screw hole 310 and the event of contacting the inner surface, so that the current measurement value iq1 (or the positive d-axis current measurement value Bd1) sets the come-out threshold Th1. The event of exceeding many times occurs. By detecting this, the come-out detection unit 54 can determine that it is a sign of come-out. On the other hand, when a come-out occurs, a sign of the come-out is first detected, and then the come-out occurs so that the tip tool 28 separates from the inner surface of the screw hole 310 and the event of contacting the inner surface does not occur. The amplitude of the measured value iq1 (or the positive d-axis current measured value Bd1) decreases. The come-out detection unit 54 can determine that a come-out has occurred by detecting a decrease in the amplitude (or positive d-axis current measurement value Bd1) of the current measurement value iq1.

The control unit 4 may reduce the rotation speed N1 of the motor 15 each time the come-out detection unit 54 detects a come-out or a sign thereof. Alternatively, the upper limit of the number of times that the control unit 4 reduces the rotation speed N1 of the motor 15 may be determined between the start of the motor 15 and the stop of the motor 15. The upper limit may be once or may be two or more times.

The power tool 1 does not have to include the impact mechanism 17.

(Summary)
From the embodiments described above, the following aspects are disclosed.

The power tool (1) according to the first aspect includes a motor (15), a control unit (4), an output shaft (21), a transmission mechanism (18), and a come-out detection unit (54). .. The control unit (4) vector-controls the motor (15). The output shaft (21) is connected to the tip tool (28). The transmission mechanism (18) transmits the power of the motor (15) to the output shaft (21). The come-out detection unit (54) detects a come-out or a sign of come-out based on a physical quantity that correlates with the amplitude of the exciting current (current measurement value id1) supplied to the motor (15). The come-out is a phenomenon in which the tip tool (28) and the screw (tightening member 30) to be worked by the tip tool (28) are released from being fitted during the operation of the motor (15).

According to the above configuration, a come-out or a sign of a come-out can be detected.

Further, in the power tool (1) according to the second aspect, in the first aspect, the control unit (4) has a come-out response function. In the come-out response function, the control unit (4) reduces the rotation speed (N1) of the motor (15) or stops the motor (15) when the come-out detection unit (54) detects a sign of come-out or come-out.

According to the above configuration, the possibility of a come-out can be reduced.

Further, in the power tool (1) according to the third aspect, in the second aspect, the control unit (4) has a first mode and a second mode as operation modes that can be switched between each other. .. In the first mode, the control unit (4) enables the come-out response function. In the second mode, the control unit (4) disables the come-out response function.

According to the above configuration, the presence / absence of the come-out response function can be switched as needed.

Further, the power tool (1) according to the fourth aspect includes a notification unit (55) in any one of the first to third aspects. The notification unit (55) notifies when the come-out detection unit (54) detects a come-out or a sign of a come-out.

According to the above configuration, the user or the like can know the occurrence of a come-out or a sign of a come-out.

Further, in the power tool (1) according to the fifth aspect, in any one of the first to fourth aspects, the transmission mechanism (18) has an impact mechanism (17). The impact mechanism (17) performs a striking operation of applying a striking force to the output shaft (21) according to the magnitude of the torque applied to the output shaft (21).

According to the above configuration, it is possible to detect a come-out or a sign of a come-out in the striking motion.

Further, in the power tool (1) according to the sixth aspect, in any one of the first to fifth aspects, the come-out detection unit (54) sets a positive peak value of the exciting current (current measurement value id1). , Used as a physical quantity that correlates with the amplitude of the exciting current.

According to the above configuration, the accuracy of detecting a come-out or a sign of a come-out can be improved.

Further, in the power tool (1) according to the seventh aspect, in the sixth aspect, the come-out detection unit (54) sets a sign of come-out or come-out as a positive peak value of the exciting current (current measurement value id1). Detect based on fluctuations.

According to the above configuration, the accuracy of detecting a come-out or a sign of a come-out can be further improved.

Configurations other than the first aspect are not essential configurations for the power tool (1) and can be omitted as appropriate.

Further, the come-out detection method according to the eighth aspect is executed for the power tool (1). The power tool (1) includes a motor (15), a control unit (4), an output shaft (21), and a transmission mechanism (18). The control unit (4) vector-controls the motor (15). The output shaft (21) is connected to the tip tool (28). The transmission mechanism (18) transmits the power of the motor (15) to the output shaft (21). The come-out detection method detects a come-out or a sign of a come-out based on a physical quantity that correlates with the amplitude of the exciting current (current measured value id1) supplied to the motor (15). The come-out is a phenomenon in which the tip tool (28) and the screw (tightening member 30) to be worked by the tip tool (28) are released from being fitted during the operation of the motor (15).

According to the above configuration, a come-out or a sign of a come-out can be detected.

Further, the program according to the ninth aspect is a program for causing one or more processors to execute the come-out detection method according to the eighth aspect.

According to the above configuration, a come-out or a sign of a come-out can be detected.

Not limited to the above aspects, various configurations (including modifications) of the power tool (1) according to the embodiment can be embodied by methods and programs.

1 Power tool 4 Control unit 15 Motor 17 Impact mechanism 18 Transmission mechanism 21 Output shaft 28 Tip tool 30 Tightening member (screw)
54 Come-out detection unit 55 Notification unit id1 Current measurement value (excitation current)
N1 rotation speed

Claims (9)

With the motor
A control unit that vector-controls the motor and
The output shaft connected to the tip tool and
A transmission mechanism that transmits the power of the motor to the output shaft,
The come-out or the sign of the come-out, which is a phenomenon in which the tip tool and the screw to be worked by the tip tool are disengaged during the operation of the motor, correlates with the amplitude of the exciting current supplied to the motor. It is equipped with a come-out detection unit that detects based on physical quantities.
Electric tool. The control unit has a come-out response function that reduces the rotation speed of the motor or stops the motor when the come-out detection unit detects the come-out or a sign of the come-out.
The power tool according to claim 1. The control unit has a first mode for enabling the come-out response function and a second mode for disabling the come-out response function as operation modes switchable to each other.
The power tool according to claim 2. The come-out detection unit includes a notification unit that notifies when the come-out or a sign of the come-out is detected.
The power tool according to any one of claims 1 to 3. 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 4. The come-out detection unit uses the positive peak value of the exciting current as the physical quantity that correlates with the amplitude of the exciting current.
The power tool according to any one of claims 1 to 5. The come-out detection unit detects the come-out or the sign of the come-out based on the fluctuation of the positive peak value of the exciting current.
The power tool according to claim 6. With the motor
A control unit that vector-controls the motor and
The output shaft connected to the tip tool and
A come-out detection method executed for an electric tool including a transmission mechanism for transmitting the power of the motor to the output shaft.
The come-out or the sign of the come-out, which is a phenomenon in which the tip tool and the screw to be worked by the tip tool are disengaged during the operation of the motor, correlates with the amplitude of the exciting current supplied to the motor. Detect based on physical quantity,
Come-out detection method. A method for causing one or more processors to execute the come-out detection method according to claim 8.
program.

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