JP2019123027A - Electric work machine - Google Patents

Abstract

To provide an electric work machine configured to perform predetermined work by receiving electric power supply from a battery to drive a motor, which can suppress interruption of the work due to the reason that the motor fails to be driven during the work, while grasping the number of work that can be executed, without acquiring battery information from the battery.SOLUTION: The electric work machine comprises a motor, an operation switch, and a control part that drives the motor when the operation switch is turned on. The control part detects a voltage of a battery when driving the motor, and if the detected battery voltage falls below a first threshold, limits the number of times of work which is executed by driving the motor within a predetermined number of times.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an electric working machine that performs a predetermined operation by receiving a power supply from a battery and driving a motor.

In this type of motorized work machine, it is necessary to supply power from the battery to the motorized work machine so that rotation of the motor can generate power necessary for the work.
However, the battery is discharged by the operation of the motorized work machine, and the amount of power that can be supplied to the motorized work machine (in other words, the remaining capacity of the battery) decreases. Therefore, with the discharge of the battery, the number of times of work that can be performed by the motorized work machine also decreases, and eventually, the operation with the motorized work machine can not be performed.

  Therefore, in this type of motorized work machine, battery information such as remaining battery capacity, battery voltage and rated capacity of battery is acquired, and based on the battery information, workable amount of work that can be performed using the battery is determined and output It is proposed to do (see, for example, Patent Document 1).

  That is, in the electric power tool described in Patent Document 1, the number of times the tightening operation of the nut can be performed is obtained and displayed from the battery information such as the remaining capacity and the electric energy required for the tightening of the nut. Therefore, the user can grasp the number of work that can be performed without replacing the battery, and the usability of the power tool can be improved.

JP, 2016-30307, A

  By the way, in the electric tool proposed above, it is necessary to obtain battery information such as remaining capacity and rated capacity from the battery in order to calculate the number of operations which is the amount of work that can be performed using the battery.

  For this reason, in the above-described proposed power tool, it is necessary to use a battery that can store and output battery information, and a battery that does not have a battery information management function can not be used.

  Further, in the above-described proposed electric power tool, since the operation amount that can be performed using the battery is output and displayed on the display unit, such as the number of operations for tightening the nut, even if the operation amount is close to zero, The user can drive the motor to carry out the work.

  In this case, the work can be continued if the work amount obtained from the remaining capacity of the battery has a margin, but if the work amount is accurately calculated, the motor can not be driven during the work and the work is It is interrupted. In this case, after the battery replacement, it is necessary to carry out the work again, and the workability is lowered.

  The present disclosure relates to an electric work machine that performs a predetermined operation by receiving a power supply from a battery and driving a motor, grasping the number of operations that can be performed without acquiring battery information from the battery, and the motor during the operation It is desirable to be able to suppress the interruption of work by not being able to drive the

  The electric working machine according to one aspect of the present disclosure is an electric working machine that can work with battery power, and includes a motor, an operation switch, and a control unit that drives the motor when the operation switch is turned on.

  And a control part detects the voltage of a battery at the time of a drive of a motor, and if the detected battery voltage falls below the 1st threshold beforehand set up as work restrictions, the number of times of operation which carries out by driving a motor afterwards Restrict to a set number of times.

  That is, when the motor is driven and work by the motorized work machine is performed, a load is applied from the work object to the motor, the current flowing to the motor increases, and the battery voltage decreases according to the remaining capacity of the battery.

Therefore, the control unit detects the battery voltage at the time of driving the motor as a parameter representing the remaining capacity of the battery without acquiring battery information such as the remaining capacity and the rated capacity from the battery.
Then, when the detected battery voltage falls below the first threshold, the control unit assumes that the number of operations that can be performed by the power supply from the battery has reached a predetermined number, and limits the number of operations thereafter to the predetermined number. is there.

  Therefore, according to the motor-driven work machine of the present disclosure, when the number of operations after the battery voltage falls below the first threshold reaches a predetermined number, the operation can not be performed even if the operation switch is operated thereafter. .

  For this reason, according to the motor-driven work machine of the present disclosure, it is possible to grasp the number of work that can be performed without acquiring battery information from the battery, and prevent the motor from being driven during work and interrupting work. It will be.

  Here, the control unit may be configured to notify that the number of operations is limited to a predetermined number. In this way, the user can grasp that the number of times of work is limited due to a decrease in the remaining capacity of the battery, and can release the restriction by charging the battery, replacing the battery, and the like. .

Further, the control unit may be configured to obtain information representing the battery voltage from the battery, and to detect the battery voltage based on the obtained information.
In this way, the control unit can detect the battery voltage without using the battery voltage detection circuit provided in the electric working machine main body, and the configuration of the electric working machine main body is simplified. be able to.

  Next, in the electric work machine, when the battery can be replaced, the predetermined number of times which is the set value when the control unit limits the number of operations after the battery voltage falls below the first threshold can be used by replacement. It may be set on the basis of a battery which makes the available period the shortest among other batteries.

  In this way, even if any of the batteries that can be used in the motorized work machine is attached to the motorized work machine, it is possible to suppress the interruption of the work because the motor can not be driven during the work. become.

  Note that, for example, a battery with the smallest capacity may be selected from among batteries that can be used by replacement as the battery with the shortest available period. In this way, it is possible to suppress that the motor can not be driven due to a decrease in the remaining capacity of the battery during work.

  However, among the available batteries, for example, based on the usage history of the battery (cell), the degree of deterioration of the battery (cell), the discharge characteristic of the battery (cell), etc. It may be selected.

  Next, the control unit may be configured to prohibit an operation performed by driving the motor next time, when the battery voltage detected at the time of driving the motor falls below a second threshold lower than the first threshold.

  In this way, even if, for example, the battery voltage has fallen below the first threshold due to battery deterioration, temporary power consumption, etc., work can not be performed a predetermined number of times, even during work. It becomes possible to suppress the interruption of work due to the inability to drive the motor.

The control unit may be configured to stop the driving of the motor when the battery voltage detected at the time of driving the motor falls below a third threshold lower than the first threshold.
In this way, when the battery voltage is greatly reduced due to a short circuit or the like at the time of driving the motor, it is possible to stop the driving of the motor and suppress the battery from being overdischarged and deteriorating.

  At the time of driving the motor, the battery voltage may be compared with the second threshold and the third threshold to prohibit the next operation or to stop the driving of the motor. In this case, the third threshold may be set to a voltage value lower than the second threshold such that the first threshold, the second threshold, and the third threshold.

  Further, the present disclosure is applicable to any electric working machine that performs a predetermined operation by driving a motor by receiving power supply from a battery, but may be applied to, for example, a nut tightening machine that tightens a nut on a bolt. .

  In this way, in the nut tightening machine, the driving of the motor is stopped with a decrease in the remaining capacity of the battery after the tightening of the nut is started by the drive of the motor until the tightening of the nut is completed. , It can control that the tightening operation of the nut is interrupted.

It is a perspective view showing the appearance of the electric tool of an embodiment. It is a block diagram showing the circuit composition of the electric tool of an embodiment. It is a flowchart showing the control processing performed by the control circuit shown in FIG. It is a flowchart showing the detail of a motor control process shown in FIG. It is a flowchart showing the detail of the voltage drop control process shown in FIG. It is a flowchart showing the detail of the display output process shown in FIG. It is a time chart showing the relation between change of battery voltage at the time of motor drive, and nut tightening operation. It is an explanatory view showing a circuit configuration of a modification which made a control circuit acquire battery voltage from a battery pack.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
In the present embodiment, a nut tightening machine will be described as an example of the motorized work machine of the present disclosure.

  The nut tightening machine 1 of the present embodiment is an electric power tool also referred to as a shear wrench, and is used for screwing and fastening a hexagonal nut to a torsia type high pressure bolt (hereinafter referred to as a shear bolt). In addition, a shear bolt is a bolt by which the tip part which can be screwed off is provided in the front-end | tip of the thread part of a bolt (in other words, the opposite side to the head of a bolt).

  For this reason, the nut tightening machine 1 of the present embodiment shears the tip by rotating the tip of the shear bolt in the direction opposite to that of the hexagonal nut after tightening the hexagonal nut with the function of tightening the hexagonal nut. And the function of cutting.

As shown in FIG. 1, the nut tightening machine 1 of the present embodiment has a tool main body 10, a motor unit 20, a handle unit 30, and a battery mounting unit 40.
The tool body 10 is rotationally driven by the motor unit 20 to exert the above-mentioned tightening function and shearing function, and a nut fitting portion capable of fitting a hexagonal nut on one end side in the central axis J direction of the body housing 12 An outer socket 14 having a 14a is provided. Further, on the inner side of the outer socket 14, an inner socket 16 having a tip fitting portion 16a into which a tip portion of a shear bolt can be fitted is provided.

  The outer socket 14 and the inner socket 16 are provided rotatably with respect to the main body housing 12 and are rotationally driven via a power transmission mechanism provided in the main body housing 12.

  That is, the outer socket 14 is rotated in the direction in which the hexagonal nut is tightened by the rotation of the motor 22 (see FIG. 2) in the motor unit 20. When the tightening of the hexagonal nut is completed and the rotation of the outer socket 14 is stopped, the reaction torque of the rotation stop causes the inner socket 16 to rotate in the reverse direction, and the tip of the shear bolt to which the hexagonal nut is tightened Let it shear.

  The tightening operation of the hexagonal nut to the shear bolt and the power transmission mechanism for rotating the outer socket 14 and the inner socket 16 for the tightening operation are described in detail in Patent Document 1, Detailed description is omitted here.

  Next, the motor unit 20 and the handle unit 30 are disposed below the tool main body 10 at predetermined intervals at which the user can grip the handle unit 30. Further, the motor portion 20 and the handle portion 30 project from the lower side of the tool body 10 in the direction orthogonal to the central axis J of the tool body 10.

  The motor unit 20 is disposed on the tip side of the tool body 10 where the outer socket 14 and the inner socket 16 are provided, and the handle portion 30 is disposed on the rear end side of the tool body 10. Further, the battery mounting portion 40 is provided below the motor portion 20 and the handle portion 30 so as to connect these portions.

  The motor unit 20 accommodates a motor 22 for rotationally driving the power transmission mechanism in the main body housing 12. The motor 22 is disposed such that the rotation axis is orthogonal to the central axis J of the tool body 10, and the power transmission mechanism in the body housing 12 from the motor 22 rotates the motor 22 at the central axis J of the tool body 10. The rotation of the motor 22 is transmitted via a gear mechanism that converts it to rotation around it.

  The handle portion 30 is used to lift the nut tightening device 1 and perform the above-described tightening operation of the hexagonal nut, as the user holds it by hand. For this reason, the handle portion 30 is provided with the trigger operating portion 32 and the lock button 34 so that the user can operate with the finger while gripping the handle portion 30.

  The trigger operation unit 32 is an operation unit for inputting a drive command of the motor 22 when the user performs a pull operation, and when the trigger operation unit 32 is pulled, a trigger provided in the handle unit 30 The switch 36 (see FIG. 2) is turned on. The trigger switch 36 corresponds to the operation switch of the present disclosure. Hereinafter, the trigger switch is referred to as a trigger SW.

  The lock button 34 is an operation unit for switching whether the trigger operation unit 32 can be operated or fixed (locked) to the non-operation position, and the trigger operation unit 32 operates according to the operation position of the lock button 34. It is switched to the locked state or the unlocked state.

Next, the battery mounting portion 40 is configured such that the battery packs 50A and 50B can be detachably mounted on the lower surface opposite to the motor portion 20 and the handle portion 30.
The battery packs 50A and 50B are DC power supplies in which a rechargeable battery, such as a lithium ion battery, is stored, for example, and are used to supply DC power to the motor drive unit 70 (see FIG. 2).

  The battery mounting portion 40 is provided with protective frames 42 and 44 that surround and protect the battery packs 50A and 50B so that the mounted battery packs 50A and 50B are not damaged by objects in the vicinity. . The battery packs 50A and 50B correspond to the battery of the present disclosure.

  As shown in FIG. 2, the motor 22 is constituted by a three-phase brushless motor provided with armature windings of U, V and W phases. The motor 22 is provided with a rotation sensor 24 for detecting the rotational position (angle) of the motor 22.

  The rotation sensor 24 includes, for example, three Hall elements arranged corresponding to each phase of the motor 22, and is a Hall IC or the like configured to generate a rotation detection signal at each predetermined rotation angle of the motor 22. Is configured.

Further, the motor drive unit 70 is housed in the handle unit 30, and receives power supply from the battery packs 50A and 50B to drive and control the motor 22.
The motor drive unit 70 is provided with a bridge circuit 72 for driving the motor, a driver circuit 74, and a control circuit 80.

  The bridge circuit 72 receives power supply from the battery packs 50A and 50B to supply current to each phase winding of the motor 22. In the present embodiment, a three-phase circuit consisting of six switching elements Q1 to Q6 is used. It is configured as a full bridge circuit. Each of the switching elements Q1 to Q6 is a MOSFET in this embodiment.

  In the bridge circuit 72, the three switching elements Q1 to Q3 are provided as so-called high side switches between the terminals U, V, W of the motor 22 and the power supply line connected to the positive electrode side of the battery. .

  Further, the other three switching elements Q4 to Q6 are provided as so-called low side switches between the terminals U, V and W of the motor 22 and the ground line connected to the negative electrode side of the battery.

A capacitor C1 is provided in the power supply path from the battery packs 50A, 50B to the bridge circuit 72 for suppressing voltage fluctuation of the battery voltage.
The driver circuit 74 turns on / off each switching element Q1 to Q6 in the bridge circuit 72 in accordance with the control signal output from the control circuit 80, thereby causing current to flow in each phase winding of the motor 22, thereby Rotate.

  Next, the control circuit 80 corresponds to the control unit of the present disclosure, and is configured by an MCU (Micro Controller Unit) including a CPU, a ROM, a RAM, and the like. Then, when the trigger operation unit 32 is operated and the trigger switch 36 is turned on, a control signal for driving the motor is output to the driver circuit 74 to rotate the motor 22.

  Control circuit 80 operates in response to a power supply voltage (DC constant voltage) generated by a regulator (not shown) in motor drive unit 70. The regulator receives power supply from battery packs 50A and 50B to generate a power supply voltage for driving control circuit 80. The generated power supply voltage is also used to operate peripheral circuits of control circuit 80. It is used.

  Next, the motor drive unit 70 is provided with a current detection circuit 76, a voltage detection circuit 78, a rotor position detection circuit 82, and a temperature detection circuit 86 as peripheral circuits, and the control circuit 80 includes these components. The detection signal from each detection circuit is also input.

  The current detection circuit 76 includes a resistor R1 connected in series to the current-carrying path on the negative electrode side of the motor 22, and detects the voltage across the motor as a motor current. In addition, the voltage detection circuit 78 detects the battery voltage supplied from the battery packs 50A and 50B.

  The temperature detection circuit 86 detects the temperature of the motor drive unit 70 based on the detection signal from the temperature sensor 84, and the rotor position detection circuit 82 detects the temperature of the motor 22 based on the detection signal from the rotation sensor 24. The rotational position and the rotational speed are detected.

  Then, when the trigger SW 36 is turned on, the control circuit 80 monitors the states of the motor 22, the battery packs 50A and 50B, and the motor drive unit 70 based on the detection signals from the detection circuits, while the motor 22 is monitored. Drive control.

  The control circuit 80 is also connected to a display unit 88 provided on the tool body 10 or the handle unit 30. The display unit 88 is for displaying the operation state of the nut tightening machine 1 to notify the user, and is configured by an LED or the like.

  Then, when the number of times of tightening of the nut is limited or the tightening operation of the nut is prohibited or stopped, the control circuit 80 performs the predetermined operation of the display unit 88 when the remaining capacity of the battery packs 50A and 50B decreases. The LED of (1) blinks or lights up to notify that.

Next, control processing executed to control drive of the motor 22 in the control circuit 80 will be described.
As shown in FIG. 3, the control circuit 80 repeatedly executes a series of processing of S120 to S160 (S represents a step) at a predetermined control cycle (time base).

  That is, control circuit 80 waits for a predetermined control period to elapse by determining whether the time base has elapsed in S110, and if it is determined that the time base has elapsed in S110, the process proceeds to S120. Transition.

  At S120, an input process is executed to take in signals from the trigger SW 36 and the rotor position detection circuit 82. In S130, an A / D conversion process is executed to A / D convert and take in the detection signals from the current detection circuit 76, the voltage detection circuit 78, and the temperature detection circuit 86.

  In the A / D conversion process, it is determined whether the motor current, the battery voltage, and the temperature of the motor drive unit 70 obtained by A / D conversion are within the normal range, and either is normal. If not within the range, it is determined that an abnormality has occurred in the drive system of the motor 22.

  Next, in S140, when the motor 22 is driven, the drive of the motor 22 is restricted based on the battery voltage obtained by the A / D conversion process of the voltage detection circuit 78 and S130, or the drive of the motor 22 is prohibited or The voltage drop control process is executed to determine whether to stop.

  In S150, the motor control process is executed to drive or stop the motor 22 in accordance with the determination result in S130 or S140 when the trigger SW 36 is in the on state. Then, finally, in S160, display output processing is performed to notify of the operation state of the nut tightening machine 1 via the display unit 88, and the process proceeds to S110.

Here, the motor control process of S150 is performed in the procedure shown in FIG.
That is, in the motor control process, first, at S210, it is determined whether or not the trigger switch 36 is in the on state.

Then, if the trigger switch 36 is not in the on state, the process proceeds to S250, in which the motor drive stop processing of stopping the driving of the motor 22 is executed, and the motor control processing is ended.
On the other hand, if the trigger SW 36 is in the on state, the process proceeds to S220, and it is determined whether the drive system of the motor 22 is normal based on the determination result in the A / D conversion process described above. Then, if there is an abnormality in the drive system of the motor 22, the process proceeds to S250, the motor drive stop processing is executed, and the motor control processing is ended.

  If it is determined in S220 that the drive system of the motor 22 is normal (in other words, there is no abnormality), the process proceeds to S230, and the voltage reduction control processing of S140 causes the motor 22 stop request flag It is determined whether or not is set.

Then, if the stop request flag is set, the process proceeds to S250, the motor drive stop process is executed, and the motor control process is ended.
When it is determined in S230 that the stop request flag of the motor 22 is not set, the process proceeds to S240. Then, in S240, a predetermined current set in advance is supplied to the motor 22 to execute motor drive processing for rotating the motor 22, and the motor control processing is completed.

Next, the voltage drop control process of S140 is performed in the procedure shown in FIG.
As shown in FIG. 5, in the voltage drop control process, it is first determined in S310 whether or not the motor 22 is being driven in the above-described motor control process.

Then, if the motor 22 is currently being driven, the process proceeds to S320, and it is determined by the driving of the motor 22 whether the battery voltage is lower than a preset third threshold Vth3.
The third threshold value Vth3 is set by driving the motor 22 to a minimum voltage value required to perform a series of tightening operations until the hexagonal nut is tightened to shear the tip of the shear bolt.

  Therefore, if it is determined in S320 that the battery voltage is lower than the third threshold Vth3, it is determined that the series of tightening operations can not be completed even if the driving of the motor 22 is continued. Then, the process proceeds to S330. Then, in S330, the stop request flag is set, and the process proceeds to S400. Note that, by setting the stop request flag in S330, the drive of the motor 22 is stopped in the motor control process to be performed thereafter.

  Next, when it is determined in S320 that the battery voltage is equal to or higher than the third threshold Vth3, the process proceeds to S340, and is the battery voltage lower than the second threshold Vth2 higher than the third threshold Vth3? Decide whether or not.

  If it is determined in S340 that the battery voltage has fallen below the second threshold value Vth2, then, by continuing the drive of the motor 22 this time, even if the tightening operation of the hexagonal nut can be completed, the hexagonal nut is tightened next time. It is determined that it is difficult to complete the work, and the process proceeds to S350.

Then, in S350, in order to prohibit the tightening operation of the hexagonal nut from the next time, the start prohibition request flag is set, and the process proceeds to S400.
Next, in S340, when it is determined that the battery voltage is equal to or higher than the second threshold Vth2, the process proceeds to S360, and the battery voltage is lower than the first threshold Vth1 higher than the second threshold Vth2. Determine if there is.

  The voltage value required to perform a series of tightening operations (N times) until the hexagonal nut is tightened and the tip portion of the shear bolt is sheared by driving the motor 22 is set to the first threshold value Vth1. ing.

  Note that the number of times (N times) of the series of tightening operations and the voltage value of the first threshold value Vth1 are the smallest among the battery packs that can be used as a power supply for the nut tightening machine 1 attached to the battery mounting unit 40. It is set based on the battery pack.

  This is a battery pack that can be used by being attached to the battery attachment unit 40. Regardless of the type of the battery pack, the battery voltage is always tightened a predetermined number of times (N times) after the battery voltage falls below the first threshold Vth1. In order to be able to complete the work.

  When it is determined in S360 that the battery voltage is lower than the first threshold Vth1, the process proceeds to S370, the count request flag is set, and the process proceeds to S400. When it is determined in S360 that the battery voltage is equal to or higher than the first threshold Vth1, the process directly proceeds to S400.

  If it is determined at S310 that the motor 22 is not currently being driven, the process proceeds to S380 to determine whether the start / stop request flag is set. Then, if the start / stop request flag is set, the voltage reduction control processing is ended after the stop request flag is set in S390, and if the start / stop request flag is not set, the voltage reduction control processing is performed as it is. Finish.

  Next, in S400, it is determined whether the count request flag is set. Then, if the count request flag is set, the process proceeds to S410, and if the count request flag is not set, the voltage drop control process is ended.

In S410, it is determined by driving the motor 22 whether or not the hexagonal nut has been tightened.
In the determination process of S410, for example, a load is applied to the motor 22 by the tightening operation, and it is determined whether or not the current flowing through the motor 22 has become a predetermined value or more (in other words, whether a predetermined load current flows through the motor 22). It is carried out by judging

  If it is determined in S410 that the hexagonal nut tightening operation has been performed by driving the motor 22 this time, the process proceeds to S420, and the number of stops is incremented to set the count request flag after setting. Count the number of work executions.

  Then, in S430, it is determined whether or not the value of the stop number counter has reached the predetermined number of times (N times) described above, and if the value of the stop number counter has reached the predetermined number of times (N times), S440. After setting the start inhibition request flag, the voltage drop control process is ended.

If it is determined in S430 that the value of the number-of-stops counter has not reached the predetermined number of times (N times), the voltage drop control process is ended.
Next, the display output process of S160 is performed in the procedure shown in FIG.

  That is, in the display output process, first, in S510, it is determined whether the stop request flag is set. Then, if the stop request flag is set, the drive of the motor 22 is stopped by the motor control processing, so the lighting processing to light the LED provided in the display unit 88 is performed to notify that. , And the display output process ends.

  If it is determined in S510 that the stop request flag is not set, the process proceeds to S530, and it is determined whether the count request flag is set. Then, if the count request flag is set, a blinking process of blinking the LED provided on the display unit 88 is performed, and the display output process is ended.

  If it is determined in S530 that the count request flag is not set, the process proceeds to S550, and the LED which is lit or blinked in the processing of S520 and S540 is extinguished, and the extinguishing process is performed. End output processing.

  As described above, in the nut tightening machine 1 of the present embodiment, when the trigger SW 36 is turned on, the control circuit 80 indicates that the motor current, battery voltage, temperature, etc. are normal, and the stop request flag is set. The drive of the motor 22 is started on condition that there is not.

  Further, while the motor 22 is driven, the control circuit 80 determines whether or not the battery voltage falls below the first threshold Vht1, the second threshold Vth2, and the third threshold Vth3 (Vth1> Vth2> Vth3) set in advance. .

  Then, as shown in the upper part of FIG. 7, when the battery voltage is lower than the first threshold Vth1 by the load current during driving of the motor 22, and is held between the first threshold Vth1 and the second threshold Vth2. Limit the number of shear bolts used to tighten the nut to N.

  That is, when the battery voltage falls below the first threshold Vth1 (time t1) while the motor 22 is driven, the control circuit 80 limits the number of tightening operations to a predetermined number (N times), and the number of executions is a predetermined number If it reaches N times, prohibit the subsequent tightening work.

  Therefore, according to the nut tightening machine 1 of the present embodiment, a decrease in the remaining capacity of the battery packs 50A, 50B is detected from the battery voltage, and the number of subsequent tightening operations is determined by the power supplied from the battery packs 50A, 50B. It can be limited to the number of times it can be implemented.

  For this reason, according to the nut tightening machine 1 of the present embodiment, the number of tightening operations is limited based on the battery voltage during motor drive without acquiring battery information from the battery packs 50A and 50B, and during tightening operations. It can be suppressed that the motor 22 can not be driven.

  Further, the nut tightening device 1 of the present embodiment includes the battery mounting portion 40, and any battery pack that can be mounted to the battery mounting portion 40 can be used as a power source. Therefore, battery packs having different capacities may be used as the battery packs 50A and 50B.

  On the other hand, the number of tightening operations (N times) to be restricted after the battery voltage falls below the first threshold value Vth1 is the battery pack with the smallest capacity among the battery packs that can be mounted and used in the battery mounting unit 40. It is set based on.

  Therefore, according to the nut tightening device 1 of the present embodiment, even if the battery packs 50A and 50B mounted to the battery mounting portion 40 are changed to ones having different capacities, the motor 22 can not be driven during the tightening operation. Can be suppressed.

  Further, the nut tightening machine 1 of the present embodiment is a shear wrench for tightening the nut on the shear bolt, and if the operation is interrupted during the tightening of the nut, the bolt in the middle of the work does not have a tightening torque secured. Must be removed and destroyed.

  However, according to the nut tightening machine 1 of the present embodiment, by restricting the drive of the motor 22, it is possible to suppress the inability to drive the motor during the tightening operation, so it is possible to reduce the frequency of removing and discarding the bolts. The work efficiency can be further improved.

  Further, the control circuit 80 causes the LED of the display unit 88 to blink to notify that the number of operations has been limited to a predetermined number (N times). Therefore, the user can grasp that the number of operations is limited by blinking of the LED, and can release the restriction by charging the battery, replacing the battery, and the like.

  Further, in the present embodiment, regardless of the types of the battery packs 50A and 50B, the number (N times) of limiting the tightening operation after the battery voltage falls below the first threshold value Vth1 is constant. Therefore, the number of times the tightening operation can be performed after notifying the restriction by the blinking of the LED changes, and it is possible to suppress giving the user a sense of discomfort.

  Furthermore, in the present embodiment, as shown in the interruption of FIG. 7, when the battery voltage falls below the second threshold Vth2 lower than the first threshold Vth1 during driving of the motor 22 (time point t2), the current motor 22 is Drive is continued, and the drive of the motor 22 from the next time onward is prohibited.

  Therefore, even if the battery voltage can not be tightened a predetermined number of times (N times) after the battery voltage falls below the first threshold value Vth1 due to deterioration of the battery packs 50A, 50B, temporary power consumption, etc. It can be suppressed that the motor 22 can not be driven.

  Further, in the present embodiment, as shown in the lower part of FIG. 7, when the battery voltage falls below the third threshold Vth3 lower than the second threshold Vth2 during driving of the motor 22 (time t3), the motor 22 is immediately driven. Stop.

  When the battery voltage is greatly reduced due to a short circuit or the like at the time of driving the motor 22, the driving of the motor is stopped to suppress the battery packs 50A and 50B from being overdischarged and deteriorating.

As mentioned above, although one Embodiment of this indication was described, this indication is not limited to the said embodiment, A various aspect can be taken.
For example, in the above embodiment, the control circuit 80 is described as detecting the battery voltage supplied from the battery packs 50A and 50B using the voltage detection circuit 78 provided in the motor drive unit 70.

  On the other hand, as shown in FIG. 8, when the battery pack 50A, 50B is provided with the transmitting unit 54 for detecting the voltage of the internal battery 52 and transmitting voltage information representing the battery voltage, The control circuit 80 may acquire voltage information from the transmission unit 54.

  In this case, the control circuit 80 detects the battery voltage based on the two types of voltage information transmitted from the battery packs 50A and 50B. Therefore, in this case, the control circuit 80 may use the battery voltage having a low voltage value among the battery voltages obtained from each piece of voltage information to determine the decrease of the battery voltage.

  In the above embodiment, the number of tightening operations (N times) to be restricted after the battery voltage falls below the first threshold value Vth1 is the smallest of the capacities of the battery packs that can be used by being attached to the battery attachment unit 40. It explained as setting based on a battery pack.

  However, as the battery pack used to set the number of tightening operations (N times), it is not always necessary to select the battery pack with the smallest capacity, and it is sufficient to select the battery pack with the shortest available period.

  Specifically, among battery packs that can be used by being attached to the battery attachment unit 40, based on usage history of the battery (cell), deterioration degree of the battery (cell), discharge characteristics of the battery (cell), etc. You may make it select the battery in which an available period becomes the shortest.

  Next, in the above embodiment, the present disclosure has been described as applied to the nut tightening machine 1 that functions as a shear wrench. However, the present disclosure relates to a predetermined power supply by receiving power from a battery to drive a motor. It is applicable if it is an electric working machine which performs work. Specifically, for example, even in the case of an electric power tool such as an impact driver or an electric working machine such as a piling machine, the present invention can be applied as in the above embodiment.

Moreover, although the motor 22 was demonstrated as what is comprised with a three-phase brushless motor in the said embodiment, what is necessary is just a motor which can rotationally drive the output shaft of an electrically-driven working machine.
Further, a plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. Also, a plurality of functions possessed by a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. In addition, part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above-described embodiment may be added to or replaced with the configuration of the other above-described embodiment. In addition, all the aspects contained in the technical thought specified only by the words described in the claim are an embodiment of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Nut tightening machine, 10 ... Tool main body, 12 ... Main body housing, 14 ... Outer socket, 14a ... Nut fitting part, 16 ... Inner socket, 16a ... Tip fitting part, 20 ... Motor part, 22 ... Motor, 24 ... Rotation sensor, 30 ... Handle portion, 32 ... Trigger operation part, 34 ... Lock button, 36 ... Trigger SW, 40 ... Battery mounting part, 42 ... Protection frame, 50A, 50B ... Battery pack, 52 ... Battery, 54 ... Transmission Unit 70 Motor drive unit 72 Bridge circuit 74 Driver circuit 76 Current detection circuit 78 Voltage detection circuit 80 Control circuit 82 Rotor position detection circuit 84 Temperature sensor 86 Temperature Detection circuit, 88 ... display unit.

Claims (9)

A motorized work machine that can work with battery power,
Motor,
Operation switch,
A control unit for driving the motor when the operation switch is turned on;
Equipped with
The control unit detects a voltage of the battery when the motor is driven, and when the detected battery voltage falls below a first threshold, thereafter, the number of times of operation performed by driving the motor is a predetermined number of times set in advance. A motorized work machine that is configured to limit   The motor-driven work machine according to claim 1, wherein the control unit is configured to notify that the number of times of work is limited to the predetermined number of times.   The electric working machine according to claim 1, wherein the control unit is configured to obtain information representing the battery voltage from the battery and to detect the battery voltage based on the obtained information. In the motor-driven work machine, the battery is replaceable,
The electric work according to any one of claims 1 to 3, wherein the predetermined number of times is set based on a battery which can be used for the shortest time among the batteries usable in the electric working machine. Machine.   The electrically powered device according to claim 4, wherein the battery with the shortest availability period is the battery with the smallest capacity among the batteries available in the motor-driven work machine.   The control unit is configured to prohibit an operation to be performed by driving the motor next time, when the battery voltage detected at the time of driving the motor falls below a second threshold lower than the first threshold. The electric working machine according to any one of claims 1 to 5.   The control unit is configured to stop the driving of the motor when the battery voltage detected at the time of driving the motor falls below a third threshold lower than the first threshold. Motorized work machine in any one of. The control unit
When the battery voltage detected at the time of driving the motor falls below a second threshold lower than the first threshold, the operation to drive the motor next time is prohibited.
6. The driving method according to claim 1, wherein driving of the motor is stopped when the battery voltage detected at the time of driving the motor falls below a third threshold lower than the second threshold. Electric working machine.   The electric working machine according to any one of claims 1 to 8, wherein the electric working machine is a nut tightening machine for tightening a nut on a bolt.