JP6562798B2 - Electric work equipment - Google Patents

Description

  The present invention relates to an electric working device having a brake function for generating a braking force when driving of a motor is stopped.

  2. Description of the Related Art As an electric work device, there is known an electric work device that includes a brake switching element connected in parallel to a motor, in addition to a driving switching element provided in a power supply path from a power source to a motor.

  According to this electric work device, when the driving switching element is turned off, the brake switching element is turned on, so that the brake current can be supplied to the motor and the braking force can be generated.

  On the other hand, in this type of electric working device, for example, when the switching element for driving and the switching element for brake are simultaneously turned on due to a failure of the switching element, the output of the power supply is short-circuited, and a large current (short-circuit current) is generated. It will flow.

  For this reason, it has been proposed that a fuse be provided on the energization path from the DC power supply to the motor, and that the fuse be blown to interrupt the energization path when the current in the energization path exceeds a specified value. (For example, refer to Patent Document 1).

Japanese Patent No. 5387858

  In the proposed electric working device, since the fuse is provided on the energization path from the power source to the motor, if the fuse is blown and the energization path is interrupted, the drive switching element is not broken. Can not drive the motor.

  In one aspect of the present invention, when the brake switching element is short-circuited, a large current does not flow through the drive switching element even when the drive switching element is switched on, and the motor is driven. It is an object of the present invention to provide an electric work device that can handle the above.

  An electric working device according to one aspect of the present invention is connected in series to a motor that operates by receiving power supply from a power source, a brake switching element that generates a braking force when the motor is on, and a brake switching element. And a blocking element.

  When the current or temperature flowing through the connection path with the brake switching element rises above a specified value, the cutoff element cuts off the connection path. The series circuit of the brake switching element and the cutoff element is a motor Are connected in parallel.

  For this reason, for example, when the power supply from the power source to the motor is started in a state where the switching element is short-circuited, the current flowing in the connection path between the brake switching element and the breaking element (so-called short-circuit current) The blocking element blocks the connection path.

Therefore, in this case, the switching element for brake and the driving element provided in the power supply path from the power source to the motor can be protected from overcurrent.
In particular, since the interruption element is not connected to the power supply path from the power source to the motor, but is connected in parallel to the brake switching element, the power supply path from the power supply to the motor even if the interruption element is in the interruption state. Can be used as usual.

  Therefore, when the brake switching element is short-circuited and the interruption element is in the interruption state, the brake current cannot be supplied to the motor via the brake switching element, but the motor can be driven normally. .

  Therefore, when driving of the motor is stopped, it is possible to continue driving the motor under conditions where it is not necessary to forcibly stop by generating braking force on the motor, improving the usability of electric work equipment it can.

  In addition, although the interruption | blocking element can also make temperature into the interruption | blocking conditions of a connection path instead of the electric current which flows into the connection path | route with a brake switching element, this includes an interruption | blocking element when the electric current which flows into a connection path | route rises. This is because the temperature also rises due to the internal resistance of the connection path.

  Here, when the short-circuit current flows through the brake switching element, the interrupting element interrupts the current path and protects the circuit element and power supply on the current path. When in the state, the motor cannot generate a braking force.

  For this reason, it is good to provide the control part which judges whether the interruption | blocking element is electrically connected or interrupted | blocked based on the voltage of the connection point of the switching element for brakes, and the interruption | blocking element. In this way, the state of the cutoff element can be monitored by the control unit.

  In this case, when the control unit determines that the blocking element is blocked, it may notify the fact. In this way, it is possible to prompt the user to repair or replace the interruption element. In addition, it is possible to notify the user that the brake control cannot be executed, and the safety when using the electric work device can be improved.

  Next, the control unit may be configured to permit driving of the motor even if it is determined that the blocking element is blocked. In this way, for example, even if the braking force cannot be generated when the driving of the motor is stopped, there is no problem in use. Even if the blocking element is shut off, the electric working device is continuously used. To be able to. Therefore, the user does not need to stop the work using the electric work equipment, and the usability of the equipment can be improved.

  Further, in this case, the control unit is configured to monitor the elapsed time thereafter when determining that the interruption element is interrupted, and prohibit driving of the motor when the elapsed time reaches a specified time. Also good.

  In this way, for example, during a work period in which the user uses the electric work device, the electric work device can be used even if the shut-off element is cut off, and then the motor is prohibited from driving. Thus, it is possible to prevent the use of electric working equipment. Therefore, in this case, it is possible to repair the work after the work period without deteriorating work efficiency using the electric work device.

On the other hand, the control unit may be configured to prohibit driving of the motor when it is determined that the blocking element is blocked.
In this way, in an electric work device that needs to generate a braking force when the motor stops driving and to stop the motor quickly, the electric work is performed when the breaking element is cut off and the brake control cannot be performed. The device can be prevented from being used immediately. Therefore, in this case, priority can be given to safety in use of the electric work equipment.

  In addition, as described above, as an electric working device that cannot be used immediately when the breaking element is cut off and brake control cannot be performed, a member housed in a container is driven into a workpiece by rotation of a motor. A driving tool can be mentioned.

  That is, in the case of a driving tool, if the motor cannot be stopped by brake control, the driving operation is continued until the motor stops rotating even if the driving of the motor is stopped. For this reason, when the breaking element is cut off and the brake control can no longer be performed, the driving of the motor is immediately prohibited, thereby suppressing the driving operation against the user's intention.

It is a perspective view showing the appearance of the electric work equipment of an embodiment. It is a block diagram showing the structure of the motor drive device incorporated in the electric work equipment. It is a flowchart showing the motor drive process performed with a control circuit. It is a flowchart showing the failure diagnosis process performed with a control circuit. It is a flowchart showing the modification of a motor drive process.

Embodiments of the present invention will be described below with reference to the drawings.
In the present embodiment, a rechargeable pin tacker that is an example of an electric work device will be described.
The rechargeable pin tacker 2 is a so-called driving tool, and is loaded with a main body 4, a battery pack 6 that is detachably attached to the main body 4, and a pin 8 as a driving material to be driven into a workpiece. The magazine 9 is mainly configured.

  The main body 4 includes a motor housing 12 in which a motor 30 (see FIG. 2) is accommodated, a gear housing 14 that accommodates a hammer mechanism and a driving mechanism, and a hand grip 16 that is gripped by an operator.

  A hand grip 16 is disposed above the motor housing 12, a gear housing 14 is disposed at one horizontal end (right side in FIG. 1) of the motor housing 12 and the hand grip 16, and a battery pack 6 is mounted at the other horizontal end. Has been.

  A plurality of pins 8 are arranged in a row in the magazine 9 and stored in a state of being biased by a spring from one end side in the row direction (left side in FIG. 1) to the other end side (right side in FIG. 1). This is because the pin 8 on the other end side is arranged in the injection part 15 below the gear housing 14, and the hammer mechanism and driving mechanism in the gear housing 14 are used to pin the workpiece from the opening end below the injection part 15. This is to drive 8 in.

  The hammer mechanism and the driving mechanism move the hammer upward in the gear housing 14 by the rotation of the motor 30 to compress the compression coil spring, and then drive the hammer downward by the elastic force of the compression coil spring. This is a mechanism for firing the pin 8 from the injection unit 15.

  The hammer mechanism and the driving mechanism are well known as described in Patent Document 1. For example, Japanese Patent No. 4588599 describes the detailed configuration thereof, and thus the description thereof is omitted here.

  Next, the handgrip 16 is provided with a trigger 18 so that the user can operate with a finger. When the trigger 18 is pulled, a trigger switch 20 (see FIG. 2, hereinafter referred to as a trigger SW) housed in the hand grip 16 is turned on. When the trigger SW 20 is turned on, a drive command for the motor 30 is input to the control circuit 50 (see FIG. 2) described later, and the motor 30 is driven by the control circuit 50.

  The hand grip 16 is provided with a display unit 22 (see FIG. 2) at a position (for example, an upper position in the figure) that can be confirmed by the user holding the hand grip 16. The display unit 22 is for notifying the user of the state of the rechargeable pin tacker 2 such as a state where a fuse 32 described later is blown (for example, LED), and is connected to the control circuit 50.

The hand grip 16 also houses a motor drive circuit 40 including a control circuit 50.
As shown in FIG. 2, the motor drive circuit 40 includes two drive circuits provided in a current-carrying path from the motor 30 to the negative electrode side of the battery 7 in a current-carrying path from the battery 7 to the motor 30 in the battery pack 6. Switching elements Q1 and Q2 are provided.

  In the present embodiment, the driving switching elements Q1 and Q2 are configured by n-channel MOSFETs. For this reason, the driving switching elements Q1 and Q2 are turned on when a high-level driving signal is input to the gate, and the energization path to the motor 30 (in other words, from the battery 7 which is a DC power source to the motor). A power supply path to

  Further, the motor drive circuit 40 is provided with a brake switching element Q3 that causes a brake current to flow by an electromotive force generated with the rotation of the motor 30 when driving of the motor 30 is stopped, thereby generating a braking force on the motor 30. .

  A fuse 32 is connected in series to the brake switching element Q3, and a series circuit of the fuse 32 and the brake switching element Q3 is connected in parallel to the motor 30.

  The brake switching element Q3 is composed of an n-channel MOSFET, like the drive switching elements Q1 and Q2, and is turned on when a high-level drive signal is input to the gate. A brake current is supplied to 30.

The fuse 32 is blown when a current of a specified value or more flows through the brake switching element Q3, and cuts off the connection path with the brake switching element Q3.
For this reason, for example, when the brake switching element Q3 has a short-circuit failure, when the drive switching elements Q1, Q2 are turned on and a short-circuit current flows from the positive electrode side to the negative electrode side of the battery 7, The current path can be interrupted.

  Next, the motor drive circuit 40 is provided with a control circuit 50 for controlling driving and braking of the motor 30. The driving switches Q1 and Q2 and the brake switching element Q3 are turned on / off by a drive signal from the control circuit 50.

  The control circuit 50 is configured by a microcontroller unit (MCU) including a CPU, a ROM, a RAM, and the like, and the trigger SW 20 and the display unit 22 are connected to the control circuit 50 as described above.

The motor drive circuit 40 includes three monitor circuits 41, 42, and 43.
Among these, the monitor circuit 41 monitors the voltage V1 at the connection point between the driving switching element Q1 and the driving switching element Q2 on the negative electrode side of the battery 7 in the energization path from the battery 7 to the motor 30. belongs to.

The monitor circuit 42 is also for monitoring the voltage V2 at the connection point between the drive switching element Q2 and the motor 30 in the energization path to the motor 30.
On the other hand, the monitor circuit 43 is for monitoring the voltage V3 at the connection point between the brake switching element Q3 and the fuse 32 in the brake current path connected in parallel to the motor 30.

  Each of these monitor circuits 41 to 43 has the same configuration. That is, like the monitor circuit 41 shown in FIG. 2, each of the monitor circuits 41 to 43 includes a PNP transistor Tr1, resistors R1, R2, R3, and a diode D1.

  Here, the emitter of the PNP transistor Tr1 is connected to the power supply line (power supply voltage: + Vcc) of the motor drive circuit 40, and the collector is connected to the control circuit 50 and also connected to the ground line via the resistor R2. Yes.

  The emitter and base of the PNP transistor Tr1 are connected via a resistor R1, and the base of the PNP transistor Tr1 is connected to the anode of a diode D1 via a resistor R3.

And the cathode of the diode D1 is connected to the connection point used as the monitoring object of each said voltage V1-V3.
In the monitor circuits 41 to 43, when voltages to be monitored (hereinafter referred to as monitor voltages) V1 to V3 are at a low level, a current flows through the diode D1, and the PNP transistor Tr1 is turned on. As a result, a high level signal (the same potential as the power supply voltage Vcc) is input to the control circuit 50.

  On the other hand, if the monitor voltages V1 to V3 are at a high level, no current flows through the diode D1, so that the PNP transistor Tr1 is turned off, and a signal at a low level (the same potential as the ground line) is input to the control circuit 50. Is done.

Therefore, the control circuit 50 can detect the monitor voltages V <b> 1 to V <b> 3 at the connection points based on the inputs from the monitor circuits 41.
The power supply voltage Vcc is applied to the power supply line and the ground line of the motor drive circuit 40 from a regulator that receives power supply from the battery 7 and generates a power supply voltage Vcc (DC constant voltage). The power supply voltage Vcc is supplied to each circuit in the motor drive circuit 40 including the control circuit 50.

Next, the control circuit 50 controls driving / stopping of the motor 30 according to the procedure shown in FIG.
That is, the motor driving process shown in FIG. 3 is a main routine executed in the control circuit 50, and the trigger SW 20 is turned on by determining whether or not the trigger SW 20 is turned on in S110. Wait for. In this state, it is assumed that the drive switching elements Q1, Q2 and the brake switching element Q3 are all off.

  When the user pulls the trigger 18 and the trigger SW 20 is turned on, the process proceeds to S120 where the driving switching elements Q1 and Q2 are switched to the on state and the motor 30 is started to be driven. Execute.

  Next, in S130, it is determined whether or not the fuse 32 is normal (that is, whether or not the connection path between the brake switching element Q3 and the motor 30 is connected). This determination is made based on a diagnosis result by a failure diagnosis process (see FIG. 3), which will be described later, executed in the motor drive control in S120.

  If the fuse 32 is normal, the process proceeds to S140, and the drive switching elements Q1, Q2 are switched to the OFF state at the timing when the set time required for driving the pin 8 has elapsed. In the subsequent S150, brake control is performed to turn on the brake switching element Q3.

  The brake switching element Q3 that is turned on by this brake control is switched to the off state after a certain time required for the rotation of the motor 30 to stop, and then the motor drive process proceeds to S110. To do.

  On the other hand, if it is determined in S130 that the fuse 32 is abnormal (blown state), the process proceeds to S160, where the drive switching elements Q1, Q2 are switched to an OFF state at an arbitrary timing, and then the motor drive process is performed. , S110 is entered.

That is, in S160, the driving switching elements Q1 and Q2 are switched to the OFF state, thereby prohibiting the driving of the motor 30 and stopping the operation of the rechargeable pin tacker 2.
Next, the failure diagnosis process executed in the motor drive control in S120 will be described.

  This failure diagnosis process is performed when the trigger SW 20 is switched to the on state when the driving switching elements Q1, Q2 and the brake switching element Q3 are all in the off state, and the driving of the motor 30 is started in S120. This is a process for performing failure diagnosis at the same time.

  As shown in FIG. 4, in the failure diagnosis process, first, in S210, an input signal from the monitor circuit 41 is fetched to determine whether or not the monitor voltage V1 is at a high level (hereinafter referred to as H level).

If the monitor voltage V1 is not H level, that is, if the monitor voltage V1 is low level (hereinafter referred to as L level), the process proceeds to S310.
In S310, the monitor circuit 41 detects that the monitor voltage V1 is at the L level even though the drive switching element Q1 is in the OFF state, so that the drive switching element Q1 has a short circuit failure. Diagnose. Then, the fact is stored in the nonvolatile memory 52 (see FIG. 2) built in the control circuit, and the process proceeds to S370.

  In S370, the operation of the rechargeable pin tacker 2 is stopped by turning off all the switching elements (specifically, the driving switching elements Q1, Q2 and the brake switching element Q3) provided in the motor drive circuit 40. And the failure diagnosis process is terminated.

On the other hand, if the monitor voltage V1 is at the H level, the drive switching element Q1 is not short-circuited, so the process proceeds to S220 and the drive switching element Q1 is turned on.
Next, in S230, it is determined whether or not the monitor voltage V1 is L level. If the monitor voltage V1 is not L level, the process proceeds to S320.

  In S320, the monitor circuit 41 detects that the monitor voltage V1 is at the H level even though the drive switching element Q1 is in the on state, so that the drive switching element Q1 has an open failure. Diagnose. Then, the fact is stored in the nonvolatile memory 52, and the process proceeds to S370.

  Next, when it is determined in S230 that the monitor voltage V1 is at the L level, the drive switching element Q1 is normal, so that the process proceeds to S240, the input signal from the monitor circuit 42 is taken in, and the monitor voltage It is determined whether or not V2 is at the H level.

  If the monitor voltage V2 is not at the H level, the monitor circuit 42 detects that the monitor voltage V2 is at the L level even though the drive switching element Q2 is in the OFF state. The element Q2 is diagnosed as having a short circuit failure. Then, the fact is stored in the nonvolatile memory 52, and the process proceeds to S370.

  On the other hand, if it is determined in S240 that the monitor voltage V2 is at the H level, the drive switching element Q2 has not short-circuited, so the process proceeds to S250 and the drive switching element Q2 is turned on.

In subsequent S260, it is determined whether or not the monitor voltage V2 is at the L level. If the monitor voltage V2 is not at the L level, the process proceeds to S340.
In S340, the monitor circuit 42 detects that the monitor voltage V2 is at the H level even though the drive switching elements Q1 and Q2 are in the ON state. Diagnose that Then, the fact is stored in the nonvolatile memory 52, and the process proceeds to S370.

  Next, when it is determined in S260 that the monitor voltage V2 is at the L level, the drive switching element Q2 is normal, and thus the process proceeds to S270 where the input signal from the monitor circuit 43 is taken in and the monitor voltage V2 is captured. It is determined whether V3 is at L level.

  If the monitor voltage V2 is not at the L level, the monitor circuit 43 detects that the monitor voltage V3 is at the H level even though the drive switching elements Q1 and Q2 are in the on state. Diagnose fusing. Then, the fact is stored in the nonvolatile memory 52, and the process proceeds to S360.

  In S360, the fuse 32 is currently blown (in other words, the brake current path is cut off), and the braking force cannot be generated in the motor 30 even if the brake switching element Q3 is turned on. Then, the display unit 22 is turned on or blinked.

  As a result, the user can detect that the fuse 32 is blown and brake control cannot be executed. Then, after executing the process of S360, the control circuit 50 ends the failure diagnosis process.

  If it is determined in S270 that the monitor voltage V3 is at the L level, the fuse 32 is not blown, so that the drive switching elements Q1, Q2 and the brake switching element Q3 are all diagnosed as normal. . Then, the fact is stored in the nonvolatile memory 52, and the failure diagnosis process is terminated.

  As described above, in the rechargeable pin tacker 2 of the present embodiment, the fuse 32 is connected in series to the brake switching element Q3 connected in parallel to the motor 30, and the energization path from the battery 7 to the motor 30 Is not provided with a fuse 32.

  In addition, a monitor circuit 43 that monitors the voltage V3 at the connection point between the fuse 32 and the brake switching element Q3 is provided. In the fault diagnosis process that is executed when the motor 30 is driven by the control circuit 50, The monitor voltage V3 is monitored.

  In the failure diagnosis process, whether or not the fuse 32 is blown is diagnosed from the monitor voltage V3 when the driving switching elements Q1 and Q2 are turned on. If the fuse 32 is blown, a display is made. This is notified via the unit 22.

  For this reason, even if the driving of the motor 30 is prohibited when the fuse 32 is blown in the motor driving process, the user detects that the cause is due to the blowing of the fuse 32. Measures such as fuse replacement can be taken promptly.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various aspect can be taken in the range which does not deviate from the summary of this invention.
[Modification 1]
For example, in the above-described embodiment, it has been described that when the blow of the fuse 32 is detected in the failure diagnosis process, the drive of the motor 30 is prohibited in the motor drive process. However, when the fuse 32 is blown, the brake control cannot be executed. The motor 30 can be driven by turning on the driving switching elements Q1 and Q2.

  For this reason, if it is an electric working device that can be used safely even if the brake control cannot be executed, when the blow of the fuse 32 is detected, in S360, the fact is notified via the display unit 22, Alternatively, it may be notified only by notification sound or voice.

  That is, in the motor driving process shown in FIG. 3, when the trigger SW 20 is turned on and the motor 30 is driven in S120, the process proceeds to S140 as it is without executing the determination process in S130, and the motor 30 is set to a predetermined value. You may make it stop at a timing.

In this way, the user does not need to stop the work using the electric work device when the fuse 32 is blown, and the usability of the device can be improved.
Note that examples of the electric working device that can be used safely even if the brake control cannot be executed include a screw fastening device such as an electric screwdriver, an electric working device equipped with a blade such as an electric saw, and the like.
[Modification 2]
Further, when the fusing of the fuse 32 is detected, the elapsed time thereafter is counted by a timer or the like, and as shown in FIG. 5, in the motor driving process, if the elapsed time is less than the specified time (S115). -YES), the drive of the motor 30 may be permitted.

In this way, for example, during a work period in which the user uses the electric work device, the electric work device can be used even if the fuse 32 is blown, and then the motor 30 is prohibited from being driven. Thus, the replacement of the fuse 32 can be urged.
[Modification 3]
Next, in the above embodiment, the brake switching element Q3 has been described as being connected in series with the fuse 32 as a breaker element that melts and shuts off the energization path when an overcurrent flows.

However, the interrupting element is composed of, for example, a thermostat that turns on / off the contact by a bimetal that deforms depending on the temperature, or a resistor having a positive temperature coefficient, and the resistance value increases as the temperature rises due to the energizing current. The thermistor which interrupts | blocks an electric current may be sufficient. That is, the interrupting element is not limited to a fuse, and any element that is used as an overcurrent protection element can be used.
[Modification 4]
Further, in the above-described embodiment, the motor drive circuit 40 has been described in which two drive switching elements Q1 and Q2 are provided on the energization path of the motor 30. This is to enable the driving / stopping of the motor 30 to be controlled even if one of the driving switching elements is short-circuited, and the present invention may include one driving switching element. The present invention can be applied similarly to the above embodiment.

  Further, the motor drive circuit 40 may be provided with a bridge circuit so that the energization path to the motor and the amount of current can be controlled. In this case, the same effect as that of the above embodiment can be obtained by connecting a blocking element in series to a brake switching element connected in parallel to the motor winding.

  Further, the present invention is not limited to an electric work device that operates by receiving power supply from a battery, but also an electric work device that operates by receiving power supply from an external power source such as a commercial power source, as in the above embodiment. Can be applied.

  2 ... rechargeable pin tacker, 4 ... main body, 6 ... battery pack, 7 ... battery, 8 ... pin, 9 ... magazine, 12 ... motor housing, 14 ... gear housing, 15 ... injection part, 16 ... hand grip, 18 ... Trigger, 20 ... Trigger SW, 22 ... Display, 30 ... Motor, 32 ... Fuse, 40 ... Motor drive circuit, Q1, Q2 ... Drive switching element, Q3 ... Brake switching element, 41, 42, 43 ... Monitor circuit 50, control circuit, 52, nonvolatile memory, R1, R2, R3, resistor, Tr1, transistor, D1, diode.

Claims (7)

A motor that operates by receiving power from a battery ;
A driving switching element provided in an energization path from the battery to the motor;
A brake switching element for generating a braking force on the motor when in an on state;
A blocking element that is connected in series to the brake switching element and interrupts the connection path when the current or temperature flowing through the connection path rises above a specified value;
With
Series circuit of the brake switching element and the blocking element, Rutotomoni is connected in parallel to said motor, in the series circuit, the breaking element is arranged on the current path side of the driving switching element is provided Has been
A monitor circuit for detecting a voltage at each connection point is provided at a connection point between the brake switching element and the cutoff element, and a connection point on the driving switching element side of the cutoff element. Electric work equipment. A controller that determines whether the blocking element is conductive or blocked based on a voltage at each of the connection points detected by the monitor circuit when the driving switching element is in an on state; The electric working device according to claim 1.   The electric working device according to claim 2, wherein when the control unit determines that the blocking element is blocked, the control unit is configured to notify that effect.   The electric work device according to claim 2 or 3, wherein the control unit is configured to permit driving of the motor even if the control unit determines that the blocking element is blocked.   The control unit is configured to monitor the elapsed time thereafter when determining that the interrupting element is interrupted, and prohibit driving of the motor when the elapsed time reaches a specified time. Item 5. The electric working device according to Item 4.   The electric working device according to claim 2 or 3, wherein the control unit is configured to prohibit driving of the motor when it is determined that the blocking element is blocked.   The electric working device according to claim 6, wherein the electric working device is a driving tool for driving a driving material stored in a container into a workpiece by rotation of a motor.

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