Work machine

Abstract

To provide a work machine capable of restraining unnecessary gall release control.SOLUTION: A work machine 1 has a motor 3, an anvil 10 capable of holding a tip tool 16 for fastening work or loosening work of a bolt or a nut, a striking mechanism for striking the anvil 10 by driving force of the motor 3, and a reciprocal switching lever 13 setting the rotation direction of the motor 3 and a trigger switch 6 for performing operation for switching driving and stopping of the motor 3, and is constituted so as to detect a gall of the tip tool 16 and the bolt or the nut from at least one variation width of a rotation speed and an electric current of the motor 3 caused by striking by the striking mechanism. The work machine 1 is constituted so as to rotate the motor 3 inversely of the set rotation direction when detecting the gall when rotating the motor 3 in the set rotation direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a work machine. [Background technology]

[0002] The following Patent Document 1 discloses a nut fastener having a second fastening mode that releases the galling (biting) between the inner socket and the nut. In the second fastening mode, when fastening is completed, the motor is rotated in the opposite direction to fastening to release the galling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-13595 A Summary of the Invention [Problem to be solved by the invention]

[0004] The configuration of Patent Document 1 cannot detect galling, and performs galling release control regardless of whether galling has occurred. This means that galling release control is performed even when galling has not occurred, which deteriorates workability.

[0005] The present invention aims to solve at least one of the following problems 1 and 2. Issue 1: To provide a work machine capable of detecting galling. Issue 2: To provide a work machine capable of suppressing unnecessary galling release control. [Means for solving the problem]

[0006] One aspect of the present invention is a work machine. A motor; A tool holder capable of holding a tool tip for tightening or loosening a bolt or nut; an impact mechanism that impacts the tool holder by a driving force of the motor; a rotation direction setting unit that sets a rotation direction of the motor; an operation unit for switching between driving and stopping the motor; a control unit that controls the motor based on an operation of the operation unit, The control unit is characterized in that it is configured to detect galling between the tool tip and the bolt or nut from a fluctuation range of at least one of the rotation speed and current of the motor accompanying the impact by the impact mechanism.

[0007] Another aspect of the present invention is a work machine. A motor; A tool holder capable of holding a tool tip for tightening or loosening a bolt or nut; an impact mechanism that impacts the tool holder by a driving force of the motor; a rotation direction setting unit that sets a rotation direction of the motor; an operation unit for switching between driving and stopping the motor; a control unit that controls the motor based on an operation of the operation unit, The control unit is a first mode in which, when galling between the tool bit and a bolt or a nut is detected while the motor is rotating in a set rotation direction, the motor is rotated in a direction opposite to the set rotation direction; a second mode in which, if the seizing is detected while the motor is rotating in a set rotation direction, the motor is rotated in a direction opposite to the set rotation direction when the motor stop operation is performed by the operation unit; The present invention is characterized in that it has at least one of the following:

[0008] The present invention may be expressed as an "electric operating machine", "electric tool", "electrical equipment", etc., and such expressions are also valid as aspects of the present invention. Effect of the Invention

[0009] According to the present invention, at least one of the above problems 1 and 2 can be solved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a side cross-sectional view of a work machine 1 according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged view taken along an arrow A in FIG. 1, showing the appearance of an operation panel 20 of the work machine 1. [Diagram 3] FIG. 2 is a circuit block diagram of the work machine 1. [Figure 4] 3 is a control flowchart of the work machine 1. [Diagram 5] 3 is a control flowchart of the work machine 1. [Figure 6] 5 is a graph showing the change over time in the rotor rotation speed (the rotation speed of the motor 3) during normal impact and during impact when galling is occurring on the work machine 1; [Figure 7] 5 is a graph showing the change over time in current flowing through a motor 3 during normal impact and during impact when galling is occurring in the work machine 1; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Fig. 1 is a side cross-sectional view of a working machine 1 according to an embodiment of the present invention. Fig. 1 defines front-rear and up-down directions in the working machine 1, which are perpendicular to each other. The front-rear direction is a direction parallel to a motor shaft 3a of the working machine 1. The working machine 1 is an electric tool, specifically an impact wrench. The working machine 1 has a housing 2.

[0012] The housing 2 includes a body portion 2a, a handle portion 2b, and a battery pack attachment portion 2c. The body portion 2a is a cylindrical portion whose central axis is approximately parallel to the front-rear direction. The housing 2 includes a hammer case 11, which is made of, for example, metal, and is connected to the front portion of the body portion 2a. The front surface of the hammer case 11 is covered with a front cap 12, which is a protective member made of elastomer or the like.

[0013] The handle portion 2b has an upper end connected to a middle portion of the body portion 2a in the front-rear direction and extends downward from the middle portion. The work machine 1 has a trigger switch 6 and a forward / reverse switching lever 13 (forward / reverse switching button) at the upper end portion of the handle portion 2b.

[0014] The trigger switch 6 is an operation unit that allows the user to switch between driving and stopping the motor 3 (the driving state of the motor 3). The trigger switch 6 is an infinitely variable speed switch. Pulling the trigger switch 6 (turning it on) is a motor driving operation, and stopping pulling the trigger switch 6 (turning it off) is a motor stopping operation.

[0015] The forward / reverse switching lever 13 is a rotation direction setting unit that enables a user to set the rotation direction of the motor 3, i.e., the rotation direction of the anvil 10 described below, to either forward or reverse.

[0016] The battery pack attachment section 2c is provided at the lower end of the handle section 2b, and the battery pack 7 can be detachably attached thereto. The work machine 1 operates using power from the battery pack 7. The work machine 1 has an operation panel 20 (switch panel) on the front upper surface of the battery pack attachment section 2c. The work machine 1 has a control board 30 inside the battery pack attachment section 2c.

[0017] The work machine 1 has a motor 3, a reduction mechanism 4, a spindle 5, a hammer 8, a spring 9, and an anvil 10 inside a body portion 2a and a hammer case 11. The reduction mechanism 4, the spindle 5, the hammer 8, and the spring 9 constitute a striking mechanism that strikes the anvil 10 with the driving force (rotational force) of the motor 3.

[0018] The motor 3 is an inner rotor type brushless motor. The reduction mechanism 4 reduces the speed of rotation of the motor 3 and transmits it to the spindle 5. The spindle 5 rotates and drives the hammer 8. The spring 9 urges the hammer 8 forward. The hammer 8 rotates or rotary strikes the anvil 10. In other words, the anvil 10 is driven by the driving force of the motor 3. The anvil 10 is rotatably supported by the hammer case 11. The anvil 10 is a tool holder capable of holding a tool tip 16 (socket) for tightening or loosening a bolt or nut.

[0019] The work machine 1 has a sensor / inverter board 15 at the rear inside the body 2a. The sensor / inverter board 15 is equipped with the temperature sensor 14, Hall IC 43, and inverter circuit 45 shown in Fig. 3. The sensor / inverter board 15 is supported at the rear of the main body of the motor 3 (the portion of the motor 3 excluding the motor shaft 3a) in a position approximately perpendicular to the motor shaft 3a.

[0020] The work machine 1 has a lighting unit 17 such as an LED for illuminating a work location, at the front lower portion of the body portion 2a.

[0021] 2 is an enlarged view taken along the line A in FIG. 1, showing the appearance of the operation panel 20. The operation panel 20 has a mode changeover switch 21, mode display LEDs 22 and 23, a strength changeover switch 25, and a strength display LED .

[0022] The mode changeover switch 21 is a mode selection section that allows the user to select one of a plurality of drive modes, which will be described later. The mode display LEDs 22 and 23 are mode display sections that display the selected drive mode.

[0023] The strong / weak changeover switch 25 is a rotation speed selection unit that allows the user to switch the maximum rotation speed of the motor 3 at no load (hereinafter referred to as the "set rotation speed") between four levels. The strong / weak display LED 26 is an intensity display unit that includes four LEDs and displays the selected set rotation speed at four levels. The number of levels at which the maximum rotation speed at no load can be set is not limited to four levels and may be any number.

[0024] Fig. 3 is a circuit block diagram of the work machine 1. Display units 22, 23, 26 are a block combining the mode display LEDs 22, 23 and the intensity display LED 26 in Fig. 2. Capacitor C is for noise prevention and is provided between the output terminals of the battery pack 7. Resistor R is for current detection or load detection and is provided in the path of the current flowing through the motor 3 (hereinafter referred to as "motor current"). Hall IC 43 (magnetic sensor) is a position sensor for detecting the rotational position of the motor 3.

[0025] The inverter circuit 45 converts the DC power output from the battery pack 7 into AC power for driving the brushless motor 6 and supplies it to the brushless motor 6. The inverter circuit 45 includes switching elements Q1 to Q6 connected in a three-phase bridge. The temperature sensor 14 is for detecting the temperature of the inverter circuit 45, and is provided in the vicinity of the switching elements Q1 to Q6.

[0026] The work machine 1 has a control board 30 which includes a current detection circuit 31, a voltage detection circuit 32, a switch operation detection circuit 33, a rotation direction setting circuit 34, a temperature detection circuit 35, a control power supply circuit 36, a control signal output circuit 37, a rotation position detection circuit 38, a rotation speed detection circuit 39, a mode setting detection circuit 40, a strong / weak setting detection circuit 41, and a calculation unit 42.

[0027] The current detection circuit 31 detects the motor current from the voltage between both terminals of the resistor R and sends it to the calculation unit 42. The calculation unit 42 can detect the load on the motor 3 from the motor current. The voltage detection circuit 32 detects the output voltage of the battery pack 7 and sends it to the calculation unit 42. The switch operation detection circuit 33 detects the on / off and operation amount (pulling amount) of the trigger switch 6 and sends it to the calculation unit 42. The rotation direction setting circuit 34 detects the rotation direction indicated by the forward / reverse switching lever 13 and sends it to the calculation unit 42. The temperature detection circuit 35 detects the temperature of the inverter circuit 45 from the output signal of the temperature sensor 14 and sends it to the calculation unit 42. The control power supply circuit 36 ​​converts the output voltage of the battery pack 7 to a power supply voltage for the calculation unit 42 and the like and supplies it to the calculation unit 42 and the like.

[0028] The control signal output circuit 37 applies a signal, for example a PWM (Pulse Width Modulation) signal, to each control terminal (each gate) of the switching elements Q1 to Q6 under the control of the calculation unit 42. The rotational position detection circuit 38 detects the rotational position of the motor 3 (hereinafter referred to as the "motor rotational position") from the output signal of the Hall IC 43, and transmits it to the calculation unit 42. The rotation speed detection circuit 39 detects the rotation speed of the motor 3 (hereinafter referred to as the "motor rotation speed") from the output signal of the rotational position detection circuit 38, and transmits it to the calculation unit 42. The mode setting detection circuit 40 detects the operation (pressing) of the mode changeover switch 21, and transmits it to the calculation unit 42. The strong / weak setting detection circuit 41 detects the operation (pressing) of the strong / weak changeover switch 25, and transmits it to the calculation unit 42.

[0029] The calculation unit 42 constitutes a control unit that controls the overall operation of the work machine 1, such as driving the motor 3 and display by the display units 22, 23, and 26. The control unit may include not only the calculation unit 42, but also the entire configuration inside the dashed line indicating the control board 30 in Fig. 3. The control unit may also include a Hall IC 43 and an inverter circuit 45.

[0030] The calculation unit 42 controls the drive of the motor 3 according to the operation of the trigger switch 6, the rotation direction set by the forward / reverse switching lever 13 (hereinafter referred to as the "set rotation direction"), the selection of the drive mode by the mode switching switch 21, and the set rotation speed selected by the strong / weak switching switch 25. The calculation unit 42 receives feedback of the motor current, the motor rotation position, and the motor rotation speed, and controls the drive of the motor 3. The calculation unit 42 is configured to be able to execute the drive mode according to the selection by the mode switching switch 21.

[0031] Hereinafter, the galling (seizing) between the tool tip 16 and the bolt or nut will be referred to as "galling." Galling is a phenomenon in which the bolt or nut expands locally due to frictional heat between the tool tip 16 and the bolt or nut, and becomes firmly attached to the tool tip 16, preventing it from moving. When galling occurs, problems such as inability to generate sufficient tightening torque occur.

[0032] The calculation unit 42 has the following multiple drive modes for the motor 3.

[0033] Automatic reverse rotation and automatic normal return mode when seizing is detected: If seizing is detected while the motor 3 is rotating in the set direction of rotation, the trigger switch 6 remains on and the motor 3 is rotated in the opposite direction to the set direction of rotation, and then the motor 3 is rotated in the set direction of rotation.

[0034] Automatic reverse rotation and manual forward return mode when seizing is detected: If seizing is detected while the motor 3 is rotating in the set direction, the trigger switch 6 remains on and the motor 3 is rotated in the opposite direction to the set direction of rotation and stopped. After that, when a new motor drive operation is performed on the trigger switch 6, that is, when a motor stop operation and a motor drive operation are performed on the trigger switch 6 in succession, the motor 3 is rotated in the set direction of rotation.

[0035] Semi-automatic reverse mode when seizing is detected: If seizing is detected while the motor 3 is rotating in the set direction, and the trigger switch 6 is operated to stop the motor, the motor 3 is rotated in the opposite direction to the set direction.

[0036] The automatic reverse rotation and automatic normal rotation return mode when seizing is detected and the automatic reverse rotation and manual normal rotation return mode when seizing is detected correspond to mode 1. The semi-automatic reverse rotation mode when seizing is detected corresponds to mode 2.

[0037] In the automatic reverse rotation and automatic return to normal rotation mode when seizing is detected, the calculation unit 42 is configured to rotate the motor 3 in a set rotation direction, detect seizing, rotate the motor 3 in a direction opposite to the set rotation direction, and rotate the motor 3 in the set rotation direction during a single motor drive operation of the trigger switch 6.

[0038] In the automatic reverse rotation and manual return to normal rotation mode when seizing is detected, the calculation unit 42 is configured to rotate the motor 3 in a set rotation direction, detect seizing, and rotate the motor 3 in the direction opposite to the set rotation direction during a single motor drive operation of the trigger switch 6.

[0039] The calculation unit 42 is configured to detect galling from the fluctuation range of at least one of the rotation speed and current of the motor 3 caused by impacts by the impact mechanism (hereinafter "impacts"). The calculation unit 42 derives the fluctuation range from the maximum and minimum values ​​of at least one of the motor rotation speed and motor current during a first predetermined time. The number of impacts per unit time is known from the specifications of the work machine 1 (such as the specifications of the motor 3 and the reduction ratio of the reduction mechanism 4), and the first predetermined time is experimentally determined so that the peak value and bottom value of the fluctuations in the motor rotation speed and motor current caused by the impacts can be detected.

[0040] When the calculation unit 42 detects seizing and / or when the calculation unit 42 detects seizing and rotates the motor 3 in the opposite direction to the set rotation direction, the calculation unit 42 may notify the user, for example, by at least one of the illumination unit 17 and the display units 22, 23, and 26. That is, at least one of the illumination unit 17 and the display units 22, 23, and 26 may function as a notification unit related to the seizing detection. Since seizing is likely to occur when a bolt or nut is worn out, notifying the user of the seizing detection has the secondary effect of also notifying the user that the bolt or nut is worn out.

[0041] 4 and 5 are control flowcharts of the work machine 1.

[0042] If the motor 3 is not being driven (No in S1), the calculation unit 42 resets the history of the motor rotation speed over the last 100 ms, and the maximum and minimum values ​​of the motor rotation speed (S3), and returns to S1. If the motor 3 is being driven (Yes in S1) and the pull amount (operation amount) of the trigger switch 6 is not fixed (has changed) (No in S5), the calculation unit 42 resets the history of the motor rotation speed over the last 100 ms, and the maximum and minimum values ​​of the motor rotation speed (S7), and returns to S1.

[0043] When the motor 3 is being driven (rotated in the set rotation direction) (Yes in S1) and the amount of pulling (operation amount) of the trigger switch 6 is fixed (not changing) (Yes in S5), the calculation unit 42 acquires the motor rotation speed in the most recent 100 ms at 1 ms intervals (S9). 100 ms is an example of the first predetermined time.

[0044] The calculation unit 42 calculates the fluctuation width of the motor rotation speed in the most recent 100 ms (hereinafter, "the most recent motor rotation speed fluctuation width"), that is, the difference between the maximum value and the minimum value of the motor rotation speed in the most recent 100 ms (S11). If the most recent motor rotation speed fluctuation width is not 3000 rpm or more (No in S13), and if the most recent motor rotation speed fluctuation width is 500 rpm or more as the auto-stop determination threshold (Yes in S15), the calculation unit 42 stops the motor 3 (S17) and returns to S1. If the motor 3 is stopped in S17, when the user performs a motor stop operation and a motor drive operation on the trigger switch 6 in sequence, the calculation unit 42 drives the motor 3 again (rotates it in the set rotation direction). If the most recent motor rotation speed fluctuation width is not 500 rpm or more (No in S15), the calculation unit 42 returns to S1.

[0045] When the latest motor rotational speed fluctuation width is equal to or greater than 3000 rpm as the threshold for determining scuffing (Yes in S13), and the mode is set to automatically reverse rotation when scuffing is detected (Yes in S19), that is, when the mode is set to the automatic reverse rotation and automatic normal rotation return mode when scuffing is detected or the automatic reverse rotation and manual normal rotation return mode when scuffing is detected, the calculation unit 42 stops the motor 3 (S21). The calculation unit 42 stops the motor 3 until the stop time of the motor 3 reaches 50 ms as the third predetermined time (No in S23), and when the stop time of the motor 3 reaches 50 ms (Yes in S23), rotates the motor 3 in the opposite direction to the set rotation direction (S25). The calculation unit 42 rotates the motor 3 in the opposite direction to the set rotation direction until the drive time of the motor 3 in the opposite direction to the set rotation direction reaches 50 ms as the second predetermined time (No in S27), and when the drive time of the motor 3 in the opposite direction to the set rotation direction reaches 50 ms (Yes in S27), stops the motor 3 (S29).

[0046] In the case of the automatic reverse rotation and automatic normal rotation return mode when scuffing is detected (Yes in S31), the calculation unit 42 rotates the motor 3 in the set rotation direction (S33), resets the history of the motor rotation speed in the last 100 ms, and the maximum and minimum values ​​of the motor rotation speed (S35), and returns to S1. Although not shown in the figure, a fourth predetermined time, for example, 50 ms, may be waited between the stopping of the motor in S29 and the rotation of the motor 3 in the set rotation direction in S33.

[0047] If the mode is not the automatic reverse rotation and automatic normal rotation return mode when seizing is detected in S31 (No in S31), that is, if the mode is the automatic reverse rotation and manual normal rotation return mode when seizing is detected, the calculation unit 42 resets the history of the motor rotation speed in the last 100 ms and the maximum and minimum values ​​of the motor rotation speed (S37) and returns to S1. In this case, when the user performs a motor stop operation and a motor drive operation on the trigger switch 6 in this order, the calculation unit 42 drives the motor 3 again (rotates it in the set rotation direction).

[0048] When the mode of automatically rotating in reverse when a galling is detected is not set in S19 (No in S19), that is, when the mode is the semi-automatic rotating in reverse when a galling is detected, the calculation unit 42 continues rotating the motor 3 in the set rotation direction until the trigger switch 6 is turned off (No in S39 and S41), and when the trigger switch 6 is turned off (Yes in S41), the calculation unit 42 stops the motor 3 (S43). The calculation unit 42 stops the motor 3 until the stop time of the motor 3 reaches 50 ms as the third predetermined time (No in S45), and when the stop time of the motor 3 reaches 50 ms (Yes in S45), the calculation unit 42 rotates the motor 3 in the opposite direction to the set rotation direction (S47). As another control example of S39 to S47, the calculation unit 42 may stop the motor 3 even if the trigger switch 6 is on after No in S19, and then rotate the motor 3 in the opposite direction to the set rotation direction when the trigger switch 6 is turned off. The calculation unit 42 rotates the motor 3 in the opposite direction to the set rotation direction until the drive time of the motor 3 in the opposite direction to the set rotation direction reaches 50 ms as the second predetermined time (No in S49), and when the drive time of the motor 3 in the opposite direction to the set rotation direction reaches 50 ms (Yes in S49), the calculation unit 42 stops the motor 3 (S51) and returns to S1. In this case, when the user performs a motor stop operation and a motor drive operation on the trigger switch 6 in this order, the calculation unit 42 drives the motor 3 again (rotates it in the set rotation direction).

[0049] FIG. 6 is a graph showing the change over time in the rotor rotation speed (motor 3 rotation speed) during normal impact of the work machine 1 and during impact when seizing is occurring. As shown in FIG. 6, the fluctuation range of the motor rotation speed due to impact is larger when seizing is occurring than during normal times (when seizing is not occurring). Using this, the calculation unit 42 detects seizing. Note that the sudden increase in the motor rotation speed during normal impact around 0.5 s in FIG. 6 is due to the completion of loosening. The increase range of the motor rotation speed per 100 ms at this time is smaller than the fluctuation range of the motor rotation speed per 100 ms when seizing is occurring, so it is possible to distinguish between the completion of loosening and the occurrence of seizing. The same can be said for the motor current.

[0050] Fig. 7 is a graph showing the change over time in motor current during normal impact and during impact when scuffing is occurring on the work machine 1. As shown in Fig. 7, the fluctuation range of the motor current accompanying an impact is larger when scuffing is occurring than during normal times (when scuffing is not occurring). The calculation unit 42 may detect scuffing from the fluctuation range of the motor current instead of or in addition to the fluctuation range of the motor rotation speed.

[0051] The description marked with * in FIG. 4 is a process for detecting seizing from the fluctuation range of the motor current. When detecting seizing from the fluctuation range of the motor current, the calculation unit 42 acquires the motor current in the most recent 100 ms at 1 ms intervals in S9. In S11, the calculation unit 42 calculates the fluctuation range of the motor current in the most recent 100 ms (hereinafter, the "most recent motor current fluctuation range"), that is, the difference between the maximum value and the minimum value of the motor current in the most recent 100 ms. In S13, the calculation unit 42 determines whether the most recent motor current fluctuation range is equal to or greater than 15 A as a seizing determination threshold. In S15, the calculation unit 42 determines whether the most recent motor current fluctuation range is equal to or greater than 5 A as an auto-stop determination threshold. In S3, S7, S35, and S37, the calculation unit 42 resets the history of the motor current in the most recent 100 ms, and the maximum and minimum values ​​of the motor current.

[0052] This embodiment provides the following advantages.

[0053] (1) Based on the knowledge that the fluctuation range of the motor rotation speed and motor current due to an impact is larger when seizing is occurring than under normal circumstances, the calculation unit 42 is configured to detect seizing from the fluctuation range of at least one of the motor rotation speed and motor current due to an impact. This makes it possible to detect seizing, unlike the conventional technology, and appropriately execute seizing release control that temporarily rotates the motor 3 in the opposite direction to the set rotation direction. In other words, unnecessary seizing release control (seizing release control when seizing is not occurring) can be suppressed, and deterioration of workability can be suppressed.

[0054] (2) The calculation unit 42 derives the fluctuation range from the maximum and minimum values ​​of at least one of the motor rotation speed and the current during the first predetermined time period, thereby making it possible to suitably derive the fluctuation range of the motor rotation speed due to the impact.

[0055] (3) In the case of the automatic reverse rotation and automatic normal rotation return mode when scuffing is detected or the automatic reverse rotation and manual normal rotation return mode when scuffing is detected, if the calculation unit 42 detects scuffing while the motor 3 is rotating in the set rotation direction, it executes the scuff release control to temporarily rotate the motor 3 in the opposite direction to the set rotation direction. This eliminates the need for the user to operate the forward / reverse switching lever 13 to release the scuffing, which is convenient. In this case, during a single motor drive operation on the trigger switch 6, the motor 3 is rotated in the set rotation direction, scuffing is detected, and the motor 3 is rotated in the opposite direction to the set rotation direction, so that the user can complete the scuff release control while keeping the trigger switch 6 on when scuffing occurs, which is convenient.

[0056] (4) In the automatic reverse rotation and automatic normal rotation return mode when scuffing is detected, the calculation unit 42 rotates the motor 3 in the set rotation direction after the scuffing release control. This allows the user to resume work after the scuffing release control with the trigger switch 6 turned on, which is convenient. At this time, after the motor 3 is rotated in the opposite direction to the set rotation direction by the scuffing release control, the motor 3 is temporarily stopped before rotating the motor 3 in the set rotation direction. This suppresses surges and prevents damage to the switching elements Q1 to Q6.

[0057] (5) In the automatic reverse rotation and manual normal rotation return mode upon scuff detection, when the trigger switch 6 is operated to drive the motor again after the scuff release control, the calculation unit 42 rotates the motor 3 in the set rotation direction. This allows the user to resume work at their own timing after the scuff release control, making it easy to use.

[0058] (6) In the semi-automatic reverse rotation mode upon scuff detection, if the calculation unit 42 detects scuffing while the motor 3 is rotating in the set rotation direction, when the trigger switch 6 is operated to stop the motor, the calculation unit 42 executes scuff release control to temporarily rotate the motor 3 in the opposite direction to the set rotation direction. This allows the user to execute the scuff release control at their own timing, making it easy to use.

[0059] (7) In the seizing release control, the calculation unit 42 temporarily stops the motor 3 before rotating the motor 3 in the direction opposite to the set rotation direction. This suppresses surges and prevents damage to the switching elements Q1 to Q6.

[0060] (8) The user can select from among an automatic reverse rotation and automatic normal rotation return mode when seizing is detected, an automatic reverse rotation and manual normal rotation return mode when seizing is detected, and a semi-automatic reverse rotation mode when seizing is detected, using the mode changeover switch 21. This allows the user to select the method of seizing release control and the subsequent work resumption according to their preference, making it easy to use.

[0061] (9) The calculation unit 42 is configured to detect galling and execute the subsequent galling release control in any drive mode selectable by the user. This reduces the risk that galling release control will not be performed when galling occurs, making the system easy to use.

[0062] (10) The calculation unit 42 is configured to detect galling and execute the subsequent galling release control regardless of whether the set rotation direction is forward or reverse. Therefore, galling detection and the subsequent galling release control are executed in both tightening and loosening of bolts or nuts, which is convenient.

[0063] (11) When the calculation unit 42 satisfies the operation completion condition (the tightening operation completion condition or the loosening operation completion condition) without detecting any galling, the calculation unit 42 is configured to stop the motor 3 even if the trigger switch 6 is on. This prevents overtightening or falling off of the bolt or nut due to a delay in turning off the trigger switch 6, improving usability.

[0064] Although the present invention has been described above by taking the embodiment as an example, the present invention is not limited to the embodiment. Various modifications can be made to each of the details specifically described in the embodiment within the scope of the claims.

[0065] The time, motor rotation speed, motor current, etc., given as specific numerical values ​​in the embodiments do not limit the scope of the invention in any way, and can be changed arbitrarily according to the required specifications. The length of time for which the motor 3 is rotated in the opposite direction to the set rotation direction in the anti-jamming control may be determined by the number of strikes, for example, by rotating the motor 3 in the opposite direction to the set rotation direction until one strike or several strikes (2 or 3 strikes). The number of strikes can be detected by the motor rotation speed. The working machine of the present invention is not limited to the impact wrench given as an example in the embodiments, and may be, for example, an impact driver. [Explanation of symbols]

[0066] 1...working machine, 2...housing, 2a...body portion, 2b...handle portion, 2c...battery pack attachment portion, 3...motor, 3a...motor shaft, 4...reduction mechanism, 5...spindle, 6...trigger switch (operation portion), 7...battery pack, 8...hammer, 9...spring, 10...anvil (tip tool holding portion), 11...hammer case, 12...front cap (protective member), 13...forward / reverse switching lever (rotation direction setting portion), 14...temperature sensor, 15...sensor / inverter board, 16...tip tool (socket), 17...lighting portion, 20...operation panel (switch panel ), 21...mode changeover switch (mode selection section), 22, 23...mode display LED, 25...strong / weak changeover switch, 26...strong / weak display LED, 30...control board, 31...current detection circuit, 32...voltage detection circuit, 33...switch operation detection circuit, 34...rotation direction setting circuit, 35...temperature detection circuit, 36...control power supply circuit, 37...control signal output circuit, 38...rotation position detection circuit, 39...rotation speed detection circuit, 40...mode setting detection circuit, 41...strong / weak setting detection circuit, 42...calculation section (control section), 43...Hall IC (magnetic sensor), 45...inverter circuit.

Claims

1. A motor; A tool holder capable of holding a tool tip for tightening or loosening a bolt or nut; an impact mechanism that impacts the tool holder by a driving force of the motor; a rotation direction setting unit that sets a rotation direction of the motor; an operation unit for switching between driving and stopping the motor; a control unit that controls the motor based on an operation of the operation unit, The control unit is configured to detect galling between the tool bit and the bolt or nut from a fluctuation range of at least one of the rotation speed and current of the motor caused by the impact by the impact mechanism. A work machine characterized by:

2. The work machine according to claim 1, The control unit derives the fluctuation range from a maximum value and a minimum value of at least one of the rotation speed and the current of the motor during a first predetermined time. A work machine characterized by:

3. The work machine according to claim 1, When the control unit detects the seizing while the motor is rotating in a set rotation direction, the control unit rotates the motor in a direction opposite to the set rotation direction. A work machine characterized by:

4. The working machine according to claim 3, The control unit is configured to be able to rotate the motor in the set rotation direction, detect the seizing, and rotate the motor in the direction opposite to the set rotation direction during a single motor drive operation of the operation unit. A work machine characterized by:

5. The work machine according to claim 1, When the control unit detects the scuffing while the motor is rotating in a set rotation direction, the control unit causes the motor to rotate in a direction opposite to the set rotation direction when a motor stop operation is performed on the operation unit. A work machine characterized by:

6. A work machine according to any one of claims 3 to 5, the control unit temporarily stops the motor after detecting the seizing and before rotating the motor in the direction opposite to the set rotation direction. A work machine characterized by:

7. A motor; A tool holder capable of holding a tool tip for tightening or loosening a bolt or nut; an impact mechanism that impacts the tool holder by a driving force of the motor; a rotation direction setting unit that sets a rotation direction of the motor; an operation unit for switching between driving and stopping the motor; a control unit that controls the motor based on an operation of the operation unit, The control unit is a first mode in which, when galling between the tool bit and a bolt or a nut is detected while the motor is rotating in a set rotation direction, the motor is rotated in a direction opposite to the set rotation direction; a second mode in which, if the seizing is detected while the motor is rotating in a set rotation direction, the motor is rotated in a direction opposite to the set rotation direction when the motor stop operation is performed by the operation unit; having at least one of A work machine characterized by:

8. The work machine according to claim 7, the control unit has the first mode and the second mode, A user is configured to select either the first mode or the second mode. A work machine characterized by:

9. A work machine according to any one of claims 3, 4, 7 and 8, the control unit rotates the motor in the set rotation direction after rotating the motor in the opposite direction to the set rotation direction upon detection of the galling. A work machine characterized by:

10. The work machine according to claim 9, The control unit is configured to be able to execute, during a single motor drive operation of the operation unit, rotation of the motor in the set rotation direction, detection of the seizing, rotation of the motor in a direction opposite to the set rotation direction, and rotation of the motor in the set rotation direction. A work machine characterized by:

11. The work machine according to claim 9, the control unit, upon detection of the galling, causes the motor to rotate in a direction opposite to the set rotation direction, and then temporarily stops the motor before causing the motor to rotate in the set rotation direction. A work machine characterized by:

12. A work machine according to any one of claims 3 to 5, 7 and 8, The control unit rotates the motor in the opposite direction to the set rotation direction upon detection of the seizing, and then stops the motor, and thereafter, when a new motor drive operation is performed on the operation unit, rotates the motor in the set rotation direction, or the control unit rotates the motor in the opposite direction to the set rotation direction upon detection of the seizing, and stops the motor when a second predetermined time has elapsed or when impacts by the impact mechanism have been detected a predetermined number of times. A work machine characterized by:

13. A work machine according to any one of claims 3 to 5, 7 and 8, The control unit has a plurality of drive modes selectable by a user, and is configured to detect the galling and thereafter rotate the motor in a direction opposite to the set rotation direction in any of the drive modes. A work machine characterized by:

14. A work machine according to any one of claims 3 to 5, 7 and 8, The control unit is configured to detect the galling and thereafter rotate the motor in the direction opposite to the set rotation direction, regardless of whether the set rotation direction is forward or reverse. A work machine characterized by:

15. A work machine according to any one of claims 1 to 5, 7 and 8, The control unit is configured to stop the motor when a task completion condition is satisfied without detecting the galling. A work machine characterized by:

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