阅读说明：本技术 电动作业机 (Electric working machine ) 是由 薮口教定 于 2021-05-26 设计创作，主要内容包括：本公开的一个方面的电动作业机具备：马达、操作部、控制部、以及反冲检测部。操作部由使用者进行操作。若操作部被操作,则控制部使马达旋转。反冲检测部检测反冲,反冲是指该电动作业机从作业对象弹回的现象。控制部执行第1制动控制以及第2制动控制。第1制动控制为如下控制,即,在由反冲检测部检测到反冲的情况下,控制部针对马达产生第1制动力。第2制动控制为如下控制,即,在从操作部被操作的操作状态已改变为操作部未被操作的非操作状态的情况下,控制部针对马达产生比第1制动力弱的第2制动力。(An electric working machine according to an aspect of the present disclosure includes: a motor, an operation unit, a control unit, and a backlash detecting unit. The operation unit is operated by a user. When the operation unit is operated, the control unit rotates the motor. The kickback detection unit detects a kickback, which is a phenomenon in which the electric working machine rebounds from the work object. The control unit executes the 1 st brake control and the 2 nd brake control. The 1 st brake control is control in which the control unit generates a 1 st braking force for the motor when a backlash is detected by the backlash detecting unit. The 2 nd braking control is control in which the control section generates a 2 nd braking force weaker than the 1 st braking force with respect to the motor in a case where the operating state in which the operating section has been operated has changed to the non-operating state in which the operating section has not been operated.)

1. An electric working machine is characterized by comprising:

a motor;

an operation unit configured to be operated by a user;

a control unit configured to rotate the motor when the operation unit is operated; and

a kickback detection unit configured to detect a kickback, which is a phenomenon in which the electric working machine rebounds from the work object,

the control unit is configured to execute a 1 st brake control and a 2 nd brake control,

the 1 st brake control is control in which, when the backlash is detected by the backlash detecting section, the control section generates a 1 st braking force for stopping rotation of the motor with respect to the motor,

the 2 nd braking control is control in which the control portion generates a 2 nd braking force weaker than the 1 st braking force with respect to the motor in a case where an operation state in which the operation portion is operated has been changed to a non-operation state in which the operation portion is not operated.

2. The electric working machine according to claim 1,

the motor is a three-phase brushless motor,

the electric working machine further includes an inverter configured to have a plurality of switching elements and to supply a three-phase alternating current to the motor,

the 1 st braking control is control in which the control portion switches on and off states of a plurality of the switching elements according to a motor rotation angle of the motor to generate the 1 st braking force,

the 2 nd braking control is control in which the control portion switches on and off states of a plurality of the switching elements according to the motor rotation angle of the motor to generate the 2 nd braking force,

the motor rotation angle at which the control portion switches the on state and the off state of the plurality of switching elements in the 1 st braking control and the motor rotation angle at which the control portion switches the on state and the off state of the plurality of switching elements in the 2 nd braking control are different from each other.

3. The electric working machine according to claim 2,

the 1 st braking control is control in which the control unit switches an on state and an off state of the plurality of switching elements to generate the 1 st braking force at a timing when the motor rotates by a 1 st braking delay angle set in advance from a reference timing set in advance,

the 2 nd braking control is control in which the control unit switches an on state and an off state of the plurality of switching elements at a timing when the motor rotates by a 2 nd braking delay angle set in advance from the reference timing to generate the 2 nd braking force,

the 2 nd braking retardation angle is greater than the 1 st braking retardation angle.

4. The electric working machine according to claim 1,

the 1 st brake control is control in which the control unit generates the 1 st braking force by at least three-phase short-circuit braking,

the 2 nd brake control is control in which the control unit generates the 2 nd braking force by at least two-phase short-circuit braking.

5. The electric working machine according to claim 2,

a proportion of a three-phase braking period in the 1 st braking control is larger than a proportion of a three-phase braking period in the 2 nd braking control, the three-phase braking period being a time during which a braking force is generated for the motor by flowing a current through all of three phases of the three-phase brushless motor,

a ratio of a two-phase braking period in the 2 nd braking control is larger than a ratio of a two-phase braking period in the 1 st braking control, the two-phase braking period being a time during which the braking force is generated by flowing a current through two of three phases of the three-phase brushless motor.

6. The electric working machine according to claim 2,

a ratio of a two-phase braking period in the 1 st braking control is larger than a ratio of a two-phase braking period in the 2 nd braking control, the two-phase braking period being a time during which a braking force is generated for the motor by flowing a current through two of three phases of the three-phase brushless motor,

a proportion of a off braking period in the 2 nd braking control is larger than a proportion of an off braking period in the 1 st braking control, the off braking period being a time during which the braking force is generated by not passing a current through all of the three phases of the three-phase brushless motor.

7. An electric working machine is characterized by comprising:

a motor;

an operation unit configured to be operated by a user;

a control unit configured to rotate the motor when the operation unit is operated; and

a kickback detection unit configured to detect a kickback, which is a phenomenon in which the electric working machine rebounds from the work object,

the control unit is configured to execute a 3 rd brake control and a 4 th brake control,

the 3 rd brake control is control in which the control portion generates a braking force for stopping rotation of the motor immediately after the kickback is detected by the kickback detection portion,

the 4 th braking control is control in which the control portion generates the braking force after a preset standby time has elapsed in a case where the operating state in which the operating portion is operated has been changed to a non-operating state in which the operating portion is not operated.

8. An electric working machine is characterized by comprising:

a motor;

an operation unit configured to be operated by a user;

a control unit configured to rotate the motor when the operation unit is operated; and

a kickback detection unit configured to detect a kickback, which is a phenomenon in which the electric working machine rebounds from the work object,

the control unit is configured to execute a 5 th brake control and a 6 th brake control,

the 5 th brake control is control in which the control portion generates a braking force for stopping rotation of the motor immediately after the kickback is detected by the kickback detection portion,

the 6 th braking control is control in which, in a case where the operating state in which the operating portion is operated has been changed to the non-operating state in which the operating portion is not operated, the control portion generates the braking force after a motor rotation speed of the motor reaches a predetermined rotation speed set in advance or less.

Technical Field

The present disclosure relates to an electric working machine.

Background

Patent document 1 describes a technique of stopping power supply to an electric working machine when a backlash of the electric working machine rebounding from a work object is detected.

Documents of the prior art

Patent document

Patent document 1: japanese examined patent publication (Kokoku) No. 1-6898

Disclosure of Invention

Problems to be solved by the invention

When the brake is applied to the motor when the tool of the electric working machine is rotating, the rotation of the tool can be stopped more quickly than when the brake is not applied, but the reaction to the user increases at the same time. The reaction is greater at higher rotational speeds. It is desirable to immediately stop the rotation of the motor of the electric working machine when the backlash occurs; and does not immediately stop the rotation of the motor in the case where the backlash does not occur.

The present disclosure aims to reduce a reaction to a user by shortening a time until a motor stops rotating when a backlash occurs and by lengthening a time until the motor stops rotating when a user turns off an operation switch for rotating the motor.

Technical scheme for solving problems

One aspect of the present disclosure is an electric working machine including: a motor, an operation unit, a control unit, and a backlash detecting unit.

The operation unit is configured to be operated by a user. The control unit is configured to rotate the motor when the operation unit is operated.

The kickback detection unit is configured to detect a kickback, which is a phenomenon in which the electric working machine rebounds from the work object. The control unit executes the 1 st brake control and the 2 nd brake control.

The 1 st brake control is control in which, when a backlash is detected by the backlash detecting unit, the control unit generates a 1 st braking force for stopping rotation of the motor with respect to the motor. The 2 nd braking control is control in which the control section generates a 2 nd braking force weaker than the 1 st braking force with respect to the motor in a case where the operating state in which the operating section has been operated has changed to the non-operating state in which the operating section has not been operated.

The electric working machine of the present disclosure configured as described above can reduce the time until the motor stops rotating by generating the 1 st braking force by the control unit when the kickback occurs. Further, when the user stops operating the operation unit, the electric working machine of the present disclosure generates a weaker braking force than when the kickback occurs, thereby making it possible to reduce the reaction caused by the decrease in the motor rotation speed. As can be seen from the above, the electric working machine according to the present disclosure can reduce the time required for the motor to stop rotating when backlash occurs, and can reduce the reaction to the user due to the decrease in the motor rotation speed when the user stops operating the operation unit.

In one aspect of the present disclosure, the motor may be a three-phase brushless motor, and the electric working machine of the present disclosure may further include an inverter having a plurality of switching elements and supplying a three-phase alternating current to the motor. Further, the 1 st braking control may be control in which the control portion switches the on state and the off state of the plurality of switching elements according to the motor rotation angle of the motor, thereby generating the 1 st braking force. Further, the 2 nd braking control may be control in which the control portion switches the on state and the off state of the plurality of switching elements according to the motor rotation angle, thereby generating the 2 nd braking force. Also, the motor rotation angle at which the control portion switches the on-state and the off-state of the plurality of switching elements in the 1 st braking control and the motor rotation angle at which the control portion switches the on-state and the off-state of the plurality of switching elements in the 2 nd braking control may be different from each other.

In one aspect of the present disclosure, the 1 st braking control may be control in which the control section switches on and off states of the plurality of switching elements at a timing when the motor rotates by a 1 st braking delay angle set in advance from a reference timing set in advance, thereby generating the 1 st braking force. The 2 nd braking control may be control in which the timing control unit switches the on state and the off state of the plurality of switching elements when the motor rotates by a 2 nd braking delay angle set in advance from the reference timing, thereby generating the 2 nd braking force. Also, the 2 nd braking retardation angle may be greater than the 1 st braking retardation angle.

In one aspect of the present disclosure, the 1 st brake control may be a control in which the control portion generates the 1 st braking force using at least three-phase short-circuit braking, and the 2 nd brake control may be a control in which the control portion generates the 2 nd braking force using at least two-phase short-circuit braking.

In one aspect of the present disclosure, a proportion of a three-phase braking period in the 1 st braking control may be larger than a proportion of a three-phase braking period in the 2 nd braking control, the three-phase braking period being a time during which a braking force is generated for the motor by flowing a current through all of three phases of the three-phase brushless motor, and a proportion of a two-phase braking period in the 2 nd braking control may be larger than a proportion of a two-phase braking period in the 1 st braking control, the two-phase braking period being a time during which a braking force is generated by flowing a current through two phases of the three-phase brushless motor.

In one aspect of the present disclosure, a proportion of a two-phase braking period in the 1 st braking control may be larger than a proportion of a two-phase braking period in the 2 nd braking control, the two-phase braking period being a time during which a braking force is generated for the motor by flowing a current through two of three phases of the three-phase brushless motor, and a proportion of a off-braking period in the 2 nd braking control may be larger than a proportion of the off-braking period in the 1 st braking control, the off-braking period being a time during which a braking force is generated by not flowing a current through all of the three phases of the three-phase brushless motor.

Another aspect of the present disclosure is an electric working machine including: a motor, an operation unit, a control unit, and a backlash detecting unit. The control unit executes 3 rd brake control and 4 th brake control.

The 3 rd brake control is control in which the control portion generates a braking force for stopping rotation of the motor immediately after the backlash is detected by the backlash detecting portion. The 4 th braking control is control in which, when the operating state in which the operating portion is operated has been changed to the non-operating state in which the operating portion is not operated, the control portion generates a braking force after a preset standby time has elapsed.

In the electric working machine of the present disclosure configured as described above, when a kickback occurs, the time until the motor stops rotating can be shortened by generating the braking force immediately after the kickback occurs. Further, when the user stops operating the operation unit, the electric working machine of the present disclosure generates a braking force after the standby time elapses, and thus, a sudden decrease in the motor rotation speed can be suppressed, and a reaction caused by the decrease in the motor rotation speed can be reduced. As can be seen from the above, the electric working machine according to the present disclosure can reduce the time required for the motor to stop rotating when backlash occurs, and can reduce the reaction to the user caused by the reduction in the rotation speed of the motor when the user stops operating the operation unit.

Another aspect of the present disclosure is an electric working machine including: a motor, an operation unit, a control unit, and a backlash detecting unit. The control unit executes 5 th brake control and 6 th brake control.

The 5 th brake control is control in which the control portion generates a braking force for stopping rotation of the motor immediately after the backlash is detected by the backlash detecting portion. The 6 th brake control is control in which, in a case where the operating state in which the operating portion is operated has been changed to the non-operating state in which the operating portion is not operated, the control portion generates a braking force after the motor rotation speed of the motor reaches a predetermined rotation speed set in advance or less.

In the electric working machine of the present disclosure configured as described above, when a kickback occurs, the time until the motor stops rotating can be shortened by generating the braking force immediately after the kickback occurs. Further, when the user stops operating the operation unit, the electric working machine of the present disclosure generates the braking force after the rotation speed of the motor reaches the predetermined rotation speed or less, thereby suppressing a sudden decrease in the rotation speed of the motor and reducing a reaction caused by the decrease in the rotation speed of the motor. As can be seen from the above, the electric working machine according to the present disclosure can reduce the time required for the motor to stop rotating when backlash occurs, and can reduce the reaction to the user caused by the reduction in the rotation speed of the motor when the user stops operating the operation unit.

Drawings

Fig. 1 is a perspective view showing the entire configuration of an electric working machine.

Fig. 2 is a block diagram showing an electrical configuration of the electric working machine.

Fig. 3 is a time chart showing changes in the motor rotation speed in the case where the off-trigger braking process is executed.

Fig. 4 is a time chart showing a change in the motor rotation speed in the case where the kickback-time brake process is performed.

Fig. 5 is a flowchart showing the work machine control process of embodiment 1.

Fig. 6 is a flowchart showing the braking process when the disconnection is triggered.

Fig. 7 is a diagram showing a brake mode table according to embodiment 1.

Fig. 8 is a flowchart showing the braking process at the time of kickback.

Fig. 9 is a timing chart showing changes in hall sensor signals and the like in the case where the off-trigger braking process of embodiment 1 is executed.

Fig. 10 is a diagram showing a current path in the case of executing the off-trigger braking process according to embodiment 1.

Fig. 11 is a timing chart showing changes in hall sensor signals and the like in the case where the kickback-time brake process of embodiment 1 is executed.

Fig. 12 is a diagram showing a two-phase braking period and a three-phase braking period in embodiment 1.

Fig. 13 is a diagram showing a brake mode table according to embodiment 2.

Fig. 14 is a timing chart showing changes in hall sensor signals and the like in the case where the off-trigger braking process of embodiment 2 is executed.

Fig. 15 is a diagram showing a current path in the case of executing the off-trigger braking process according to embodiment 2.

Fig. 16 is a timing chart showing changes in hall sensor signals and the like in the case where the kickback-time brake process of embodiment 2 is executed.

Fig. 17 is a diagram showing a two-phase braking period and a brake off period in embodiment 2.

Fig. 18 is a flowchart showing the work machine control process according to embodiment 3.

Fig. 19 is a flowchart showing the idling process in embodiment 3.

Fig. 20 is a timing chart showing a change in the motor rotation speed when the idling process is executed in embodiment 3.

Fig. 21 is a flowchart showing the idling process of embodiment 4.

Fig. 22 is a timing chart showing a change in the motor rotation speed when the idling process of embodiment 4 is executed.

Fig. 23 is a timing chart showing changes in hall sensor signals and the like when three-phase short-circuit braking is performed.

Detailed Description

[ embodiment 1 ]

Hereinafter, embodiment 1 of the present disclosure will be described with reference to the drawings.

As shown in fig. 1, the electric working machine 1 of the present embodiment is a circular saw mainly used for cutting a workpiece.

The electric working machine 1 includes a base 2 and a main body 3. The base 2 is a substantially rectangular member that comes into contact with the upper surface of the workpiece to be cut when the workpiece is cut. The main body 3 is disposed on the upper surface side of the base 2.

The main body 3 includes a circular saw blade 4, a blade case 5, and a cover 6. The blade 4 is disposed on the right side in the cutting travel direction in the main body 3. The blade housing 5 is formed to cover a periphery of a substantially half-circumference range at an upper side of the blade 4 so as to be accommodated inside.

The cover 6 is formed to cover a peripheral edge of a substantially half-circumference range at the lower side of the saw blade 4. The cover 6 is an openable cover, and fig. 1 shows a state where the cover 6 is closed. When the electric working machine 1 is moved in the cutting travel direction when cutting the workpiece, the cover 6 is rotated counterclockwise in fig. 1 about the rotation center of the saw blade 4 and is gradually opened. This exposes the saw blade 4 and cuts the exposed portion into the workpiece.

A substantially cylindrical motor housing 7 is provided on the left side of the body portion 3. A motor 11 is housed inside the motor case 7, and the motor 11 is a drive source of the electric working machine 1. In addition, the motor 11 is not shown in fig. 1, and the motor 11 is shown in fig. 2.

A gear mechanism, not shown, is accommodated between the motor housing 7 and the saw blade 4. When the motor 11 rotates, the rotation is transmitted to the saw blade 4 via the gear mechanism, and the saw blade 4 rotates.

A grip 8 to be gripped by a user of the electric working machine 1 is disposed on an upper side of the main body portion 3. The handle 8 is fitted to the upper side in the main body 3 in an arcuate shape. That is, one end of the handle 8 is fixed to the rear end side in the cutting advancing direction in the main body portion 3, and the other end of the handle 8 is fixed to the front side in the cutting advancing direction than the rear end.

The trigger 9 is mounted on the handle 8. The user of the electric working machine 1 can perform the operation of locking and releasing the trigger 9 in a state of holding the handle 8. Further, the user of the electric working machine 1 can lock the trigger 9 in a state where the lock release lever protruding in the left-right direction of the handle 8 near the trigger 9 is operated. Specifically, the user of the electric working machine 1 can depress the lock release lever from the left or right side, thereby being able to latch the trigger 9. Hereinafter, a state in which the trigger 9 is operated to be latched is referred to as an on state, and a state in which the trigger 9 is operated to be released is referred to as an off state.

A battery pack 10 containing a rechargeable battery 12 is detachably attached to the rear end of the main body 3. When the trigger 9 is operated by being latched in a state where the battery pack 10 is attached to the main body 3, the motor 11 in the main body 3 is rotated by the power of the battery 12. In addition, the battery 12 is not shown in fig. 1, and the battery 12 is shown in fig. 2.

As shown in fig. 2, the electric working machine 1 includes a control unit 20. The control unit 20 includes a power supply terminal 20a and a ground terminal 20 b. When the battery pack 10 is mounted to the main body 3, the power terminal 20a and the ground terminal 20b are connected to the power terminal 10a and the ground terminal 10b of the battery pack 10, respectively.

The power supply terminal 10a of the battery pack 10 is connected to the positive electrode of the battery 12. The ground terminal 10b of the battery pack 10 is connected to the negative electrode of the battery 12.

The control unit 20 receives power supply from the battery 12 in the battery pack 10 and performs drive control of the motor 11. In the present embodiment, the motor 11 is a three-phase brushless motor.

The control unit 20 includes a three-phase inverter 21 and a controller 22.

The three-phase inverter 21 is a circuit for receiving power supply from the battery 12 and causing current to flow through each phase winding of the motor 11. In the present embodiment, the three-phase inverter 21 is configured as a three-phase full bridge circuit including 6 switching elements Q1, Q2, Q3, Q4, Q5, and Q6. In the present embodiment, the switching elements Q1 to Q6 are MOSFETs.

In the three-phase inverter 21, the switching elements Q1, Q3, and Q5 are disposed on a power supply line connecting each terminal U, V, W of the motor 11 and the positive electrode of the battery 12, respectively. The switching elements Q2, Q4, and Q6 are disposed on a ground line connecting the terminals U, V, W of the motor 11 and the negative electrode of the battery 12, respectively.

The controller 22 is configured mainly by a microcomputer including a CPU22a, a ROM22b, a RAM22c, and the like. Various functions of the microcomputer are realized by the CPU22a executing a program stored in a non-transitory tangible recording medium. In this example, the ROM22b corresponds to a non-transitory tangible recording medium storing a program. Further, by executing the program, a method corresponding to the program is executed. In addition, a part or all of the functions executed by the CPU22a may be configured in the form of hardware by one or more ICs or the like. Further, the number of microcomputers constituting the controller 22 may be one or more.

The electric working machine 1 further includes a trigger switch 13 and a hall sensor 15.

The trigger switch 13 includes a main switch 13a that is turned on when the trigger 9 is operated to be latched, and an operation amount detection unit 13b that detects the amount of latching of the trigger 9.

The main switch 13a outputs a trigger signal. The trigger signal is a high-level signal when the trigger 9 is in an on state in which the trigger is operated to be latched, and the trigger signal is a low-level signal when the trigger 9 is in an off state in which the trigger is operated to be released. The operation amount detection unit 13b is a variable resistor that changes a resistance value according to the amount of actuation of the trigger 9. The main switch 13a and the operation amount detection unit 13b are both connected to the controller 22.

The hall sensor 15 is a rotational position sensor provided with a hall element. The hall sensor 15 outputs U, V, W position detection signals Hu, Hv, and Hw of each phase (hereinafter referred to as hall sensor signals) based on a change in magnetic field caused by rotation of the rotor of the motor 11. The hall sensor signals Hu, Hv, Hw are switched between the high level and the low level every time the rotor of the motor 11 rotates by an electrical angle of 180 °. The phases of the hall sensor signals Hu, Hv, and Hw are shifted by 120 ° in electrical angle from each other. Therefore, each time the rotor of the motor 11 rotates by an electrical angle of 60 °, a level change edge is generated in any one of the hall sensor signals Hu, Hv, and Hw. The level change edge includes both a rising edge from a low level to a high level and a falling edge from a high level to a low level. Hereinafter, the level change edge is simply referred to as an edge. The hall sensor signals Hu, Hv, and Hw are collectively referred to as hall sensor signals H. The hall sensor signals Hu, Hv, Hw are input to the controller 22.

As shown in fig. 3, when the trigger signal is switched from the low level to the high level at time t1, the control unit 20 starts the drive process of the motor 11. Thus, the motor rotation speed gradually increases until time t2, and at time t2, the motor rotation speed corresponds to the amount of engagement of the trigger 9.

Thereafter, when the trigger signal is switched from the high level to the low level at time t3, the control unit 20 starts the off-trigger braking process described later. Thus, the motor rotation speed gradually decreases until time t4, and becomes 0rpm at time t 4.

As shown in fig. 4, when the trigger signal is switched from the low level to the high level at time t11, the control unit 20 starts the drive process of the motor 11. Thus, the motor rotation speed gradually increases until time t12, and at time t12, the motor rotation speed corresponds to the amount of engagement of the trigger 9.

Thereafter, when a kickback occurs at time t13 and the motor rotation change rate is smaller than the kickback determination change rate Jk at time t14, the control unit 20 starts a kickback-time braking process, which will be described later. Thus, the motor rotation speed gradually decreases until time t15, and becomes 0rpm at time t 15.

Next, a program of the work machine control process executed by the CPU22a of the controller 22 will be described. The work machine control process is a process repeatedly executed during the operation of the controller 22.

When the work machine control process is executed, as shown in fig. 5, the CPU22a first determines whether or not the flip-flop 9 is in the on state in S10. Here, when the trigger 9 is in the off state, the CPU22a ends the work machine control process. On the other hand, with the flip-flop 9 in the on state, the CPU22a executes the motor driving process in S20. Specifically, the CPU22a determines the electrical angle of the motor 11 based on the hall sensor signal H, and sets the respective switching elements Q1 to Q6 in the three-phase inverter 21 to the on state or the off state according to the determined electrical angle, thereby causing current to flow through the respective phase windings of the motor 11, thereby rotating the motor 11.

Next, the CPU22a executes the kickback detection process in S30. Specifically, the CPU22a first calculates the amount of change per unit time in the motor rotation speed (i.e., the motor rotation change rate). Then, the CPU22a determines whether the calculated motor rotation change rate is smaller than a preset backlash judgment change rate Jk. Here, the CPU22a determines that backlash occurs when the motor rotation change rate is smaller than the backlash determination change rate Jk. On the other hand, when the motor rotation change rate is equal to or greater than the backlash judgment change rate Jk, the CPU22a judges that backlash has not occurred.

Then, the CPU22a determines in S40 whether it has been determined in S30 that kickback is occurring. Here, in the case where kickback does not occur, the CPU22a determines in S50 whether the flip-flop 9 is in the off state. Here, in the case where the flip-flop 9 is not in the off state, the CPU22a transitions to S20.

On the other hand, when the flip-flop 9 is in the off state, the CPU22a executes a trigger off brake process described later in S60. When the off-trigger brake processing ends, the CPU22a ends the work machine control processing.

Further, in S40, in the case where kickback is occurring, the CPU22a executes a kickback-time brake process, which will be described later, in S70. When the kickback braking process is finished, the CPU22a ends the work machine control process.

Next, a description will be given of a procedure of triggering the off-time brake processing executed in S60.

When the off-trigger braking process is executed, the CPU22a first executes the edge detection process in S210, as shown in fig. 6. Specifically, the CPU22a detects whether an edge is generated in the hall sensor signals Hu, Hv, Hw.

Then, the CPU22a determines in S220 whether an edge is generated based on the detection result in S210. Here, in the case where no edge is generated, the CPU22a shifts to S270.

On the other hand, in the case where an edge is generated, the CPU22a calculates an edge interval time in S230. Specifically, the CPU22a calculates the difference between the present edge timing at which an edge is detected in the present edge detection processing and the last edge timing at which an edge was detected last time as the edge interval time.

Then, the CPU22a calculates the off-trigger standby time by equation (1) in S240. In equation (1), Tbn is the standby time at the time of trigger off, θ n is the brake delay angle at the time of trigger off, and Te is the edge interval time. In the present embodiment, the off-trigger braking delay angle θ n is 50[ ° ].

Tbn＝(θn/60°)×Te…(1)

Next, the CPU22a determines in S250 whether or not the off-trigger standby time Tbn has elapsed. Here, when the off-trigger standby time Tbn has not elapsed, the CPU22a repeats the process of S250 to wait until the off-trigger standby time Tbn has elapsed.

Then, if the off-trigger standby time Tbn has elapsed, the CPU22a sets the upper stage switching elements (i.e., the switching elements Q1, Q3, Q5) to the off state in S260, switches the on state and the off state of the lower stage switching elements (i.e., the switching elements Q2, Q4, Q6) based on the braking pattern table BT stored in the ROM22b, and then proceeds to S270.

When the process proceeds to S270, the CPU22a determines whether or not the motor 11 is in a stopped state. Here, if the motor 11 is not in the stopped state, the CPU22a proceeds to S210. On the other hand, when the motor 11 is in the stopped state, the CPU22a ends the off-time brake triggering process.

As shown in fig. 7, the brake pattern table BT sets the on state or the off state of the lower stage switching element for each of the 1 st brake period, the 2 nd brake period, the 3 rd brake period, the 4 th brake period, the 5 th brake period, and the 6 th brake period.

The switching is performed in the order of the 1 st braking period, the 2 nd braking period, the 3 rd braking period, the 4 th braking period, the 5 th braking period, and the 6 th braking period, and when the 6 th braking period ends, the switching is performed in the 1 st braking period, and the switching is repeated in the order described above.

The 1 st braking period is a period in which the hall sensor signals Hu and Hv are at a high level and the hall sensor signal Hw is at a low level. The 2 nd braking period is a period in which the hall sensor signal Hu is at a high level and the hall sensor signals Hv and Hw are at a low level.

The 3 rd braking period is a period in which the hall sensor signals Hu and Hw are at a high level and the hall sensor signal Hv is at a low level. The 4 th braking period is a period in which the hall sensor signal Hw is at a high level and the hall sensor signals Hu and Hv are at a low level.

The 5 th braking period is a period in which the hall sensor signals Hv, Hw are at high level and the hall sensor signal Hu is at low level. The 6 th braking period is a period in which the hall sensor signal Hv is at a high level and the hall sensor signals Hu and Hw are at a low level.

In the 1 st braking period and the 2 nd braking period, the switching elements Q2, Q6 are set to the on state and the switching element Q4 is set to the off state.

In the 3 rd braking period and the 4 th braking period, the switching elements Q4, Q6 are set to the on state and the switching element Q2 is set to the off state.

In the 5 th braking period and the 6 th braking period, the switching elements Q2, Q4 are set to the on state and the switching element Q6 is set to the off state.

Next, a procedure of the kickback time brake processing executed in S70 will be described.

When the kick-back braking process is executed, as shown in fig. 8, the CPU22a first executes the edge detection process in S310, which is the same as that in S210.

Then, the CPU22a determines in S320 whether an edge is generated based on the detection result in S310, as in S220. Here, in the case where no edge is generated, the CPU22a shifts to S370.

On the other hand, in the case where an edge is generated, the CPU22a calculates an edge interval time in S330, as in S230.

Then, the CPU22a calculates the recoil time standby time by equation (2) in S340. In the formula (2), Tba is a kickback standby time, θ a is a kickback braking delay angle, and Te is an edge interval time. In the present embodiment, the backlash braking delay angle θ n is 30[ ° ].

Tba＝(θa/60°)×Te…(2)

Next, the CPU22a determines in S350 whether or not the recoil time standby time Tba has elapsed. Here, when the recoil standby time Tba has not elapsed, the CPU22a repeats the processing of S350 to wait until the recoil standby time Tba has elapsed.

When the kickback standby time Tba has elapsed, the CPU22a sets the upper switching element to the off state in S360, switches the on state and the off state of the lower switching element based on the brake pattern table BT, and then proceeds to S370, as in S260.

When the process proceeds to S370, the CPU22a determines whether or not the motor 11 is in a stopped state. Here, if the motor 11 is not in the stopped state, the CPU22a proceeds to S310. On the other hand, when the motor 11 is in the stopped state, the CPU22a ends the kickback braking process.

Fig. 9 is a timing chart showing changes in hall sensor signals Hu, Hv, Hw, changes in the states of switching elements Q2, Q4, Q6, changes in U-phase current Iu, changes in V-phase current Iv, and changes in W-phase current Iw in the case where the off-trigger braking process is performed.

As shown in fig. 9, the period from time t21 to time t22 is the 1 st braking period P1. The period from the time t22 to the time t23 is the 2 nd braking period P2. The period from the time t23 to the time t24 is the 3 rd braking period P3. The period from the time t24 to the time t25 is the 4 th braking period P4. The period from the time t25 to the time t26 is the 5 th braking period P5. The period from the time t26 to the time t27 is the 6 th braking period P6. The period from the time t27 to the time t28 is the 1 st braking period P1.

When the hall sensor signal Hu has an edge at time t21 and the 1 st braking period P1 starts, the switching element Q4 is switched from the on state to the off state and the switching element Q6 is switched from the off state to the on state after the off-trigger standby time Tbn has elapsed from time t 21.

When an edge occurs in the hall sensor signal Hw at time t23 and the 3 rd braking period P3 starts, the switching element Q2 is switched from the on state to the off state and the switching element Q4 is switched from the off state to the on state after the off-trigger standby time Tbn has elapsed from time t 23.

When the hall sensor signal Hv has an edge at time t25 and the 5 th braking period P5 starts, the switching element Q6 is switched from the on state to the off state and the switching element Q2 is switched from the off state to the on state after the off-trigger standby time Tbn has elapsed from time t 25.

For example, in the 2 nd braking period P2, as shown in fig. 10, the switching elements Q1, Q3, Q5, and Q4 are in the off state, and the switching elements Q2, Q6 are in the on state. In this case, a U-phase current Iu from the ground to the motor 11 through the switching element Q2, a V-phase current Iv from the ground to the motor 11 through the switching element Q4, and a W-phase current Iw from the motor 11 to the ground through the switching element Q6 are generated.

Fig. 11 is a timing chart showing changes in the hall sensor signals Hu, Hv, Hw, the states of the switching elements Q2, Q4, Q6, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw in the case where the kickback-time braking process is performed.

As shown in fig. 11, the period from time t31 to time t32 is the 1 st braking period P1. The period from the time t32 to the time t33 is the 2 nd braking period P2. The period from the time t33 to the time t34 is the 3 rd braking period P3. The period from the time t34 to the time t35 is the 4 th braking period P4. The period from the time t35 to the time t36 is the 5 th braking period P5. The period from the time t36 to the time t37 is the 6 th braking period P6. The period from the time t37 to the time t38 is the 1 st braking period P1.

When an edge occurs in the hall sensor signal Hu at time t31 and the 1 st braking period P1 starts, the switching element Q4 is switched from the on state to the off state and the switching element Q6 is switched from the off state to the on state after the kickback standby time Tba has elapsed from time t 31.

When an edge occurs in the hall sensor signal Hw at time t33 and the 3 rd braking period P3 starts, the switching element Q2 is switched from the on state to the off state and the switching element Q4 is switched from the off state to the on state after the kickback standby time Tba elapses from time t 33.

When an edge occurs in the hall sensor signal Hv at time t35 and the 5 th braking period P5 starts, the switching element Q6 is switched from the on state to the off state and the switching element Q2 is switched from the off state to the on state after the recoil time standby time Tba elapses from time t 35.

The electric working machine 1 configured as described above includes the motor 11, the trigger 9, and the control unit 20.

The trigger 9 is operated by the user. When the trigger 9 is operated, the control unit 20 rotates the motor 11.

The control unit 20 detects backlash, which is a phenomenon in which the electric working machine 1 rebounds from the work object. The control unit 20 executes a kickback-time brake process and a trigger-off-time brake process.

In the backlash time brake process, when backlash is detected, a 1 st braking force for stopping rotation of the motor 11 is generated for the motor 11. In the trigger off-time brake processing, when it is detected that the operating state in which the trigger 9 is operated has changed to the non-operating state in which the trigger 9 is not operated, the 2 nd braking force weaker than the 1 st braking force is generated for the motor 11.

As described above, when the kickback occurs, the electric working machine 1 can generate the 1 st braking force to shorten the time until the motor stops rotating. Further, when the user stops operating the trigger 9, the electric working machine 1 generates a weaker braking force than when the kickback occurs, and thus the reaction due to the decrease in the motor rotation speed can be reduced. As described above, the electric working machine 1 can reduce the time until the motor stops rotating when the kickback occurs, and can reduce the reaction to the user due to the decrease in the motor rotation speed when the user stops operating the trigger 9.

Further, the motor 11 is a three-phase brushless motor. The electric working machine 1 further includes a three-phase inverter 21, and the three-phase inverter 21 has switching elements Q1 to Q6 and supplies a three-phase ac current to the motor 11.

In the kickback braking process, the on state and the off state of the switching elements Q1 to Q6 are switched according to the motor rotation angle of the motor 11, and the 1 st braking force is generated. In the off-time brake triggering process, the on state and the off state of the switching elements Q1 to Q6 are switched according to the motor rotation angle, thereby generating the 2 nd braking force. Further, the motor rotation angle at the time of switching the on state and the off state of the switching elements Q1 to Q6 in the case where the 1 st braking force is generated and the motor rotation angle at the time of switching the on state and the off state of the switching elements Q1 to Q6 in the case where the 2 nd braking force is generated are different from each other.

In the kickback braking process, the on state and the off state of the switching elements Q1 to Q6 are switched at a timing when the motor 11 rotates by a preset kickback braking delay angle θ a from a timing when an edge is generated in the hall sensor signals Hu, Hv, and Hw (hereinafter referred to as a reference timing), thereby generating the 1 st braking force. In the off-trigger braking process, the on state and the off state of the switching elements Q1 to Q6 are switched at a timing when the motor 11 rotates by the preset off-trigger braking delay angle θ n from the reference timing, and the 2 nd braking force is generated. Further, the off-trigger braking delay angle θ n is larger than the kickback braking delay angle θ a. Specifically, the kick-back brake delay angle θ a when the 1 st braking force is generated is 30[ ° ], and the off-trigger brake delay angle θ n when the 2 nd braking force is generated is 50[ ° ].

Further, the proportion of the three-phase braking period when the 1 st braking force is generated, which is the time for generating the braking force to the motor 11 by passing current through all of the three phases of the motor 11 as the three-phase brushless motor, is larger than that when the 2 nd braking force is generated. Further, the proportion of the two-phase braking period, which is the time during which braking force is generated by passing current through two of the three phases of the motor 11, which is a three-phase brushless motor, when the 2 nd braking force is generated is larger than when the 1 st braking force is generated.

In the case where the kick-time braking process is performed to generate the 1 st braking force, as shown in fig. 11, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw always flow during the 2 nd braking period P2, the 4 th braking period P4, and the 6 th braking period P6. On the other hand, in the 1 st braking period P1, there is a W-phase non-energization period in which the W-phase current Iw does not flow (i.e., OA). In the 3 rd braking period P3, there is a V-phase non-energization period in which the V-phase current Iv does not flow. In the 5 th braking period P5, there is a U-phase non-energization period in which the U-phase current Iu does not flow.

When the off-time brake triggering process is executed to generate the 2 nd braking force, as shown in fig. 9, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw always flow in the 2 nd braking period P2, the 4 th braking period P4, and the 6 th braking period P6. On the other hand, in the 1 st braking period P1, there is a W-phase non-energization period. In the 3 rd braking period P3, there is a V-phase non-energization period. In the 5 th braking period P5, there is a U-phase non-energization period.

The U, V, W-phase non-energization period in fig. 11 is shorter than the U, V, W-phase non-energization period in fig. 9. That is, the proportion of the three-phase braking period in the case where the kickback-time braking process is executed is larger than the proportion of the three-phase braking period in the case where the off-trigger-time braking process is executed. Further, the proportion of the two-phase braking period in the case where the off-trigger-time braking process is performed is larger than the proportion of the two-phase braking period in the case where the kickback-time braking process is performed.

As shown in fig. 12, the three-phase braking periods B12, B14, B16 in the case where the kickback-time braking process is performed are longer than the three-phase braking periods B2, B4, B6 in the case where the trigger off-time braking process is performed. Therefore, in the case where the kickback-time braking process is executed, the proportion of the three-phase braking period from the 1 st braking period P1 until the 6 th braking period P6 is larger than that in the case where the off-trigger-time braking process is executed.

Further, the two-phase braking periods B1, B3, B5 in the case where the trigger off-time braking process is performed are longer than the two-phase braking periods B11, B13, B15 in the case where the kickback-time braking process is performed. Therefore, in the case where the off-trigger braking process is executed, the proportion of the two-phase braking period from the 1 st braking period P1 to the 6 th braking period P6 is larger than that in the case where the kickback braking process is executed.

In the above-described embodiment, the flip-flop 9 corresponds to an example of the operation unit in the present disclosure, S10, S20, and S40 to S70 correspond to processing performed as an example of the control unit in the present disclosure, and S30 corresponds to processing performed as an example of the kickback detection unit in the present disclosure.

S60 corresponds to an example of the 1 st brake control in the present disclosure, S70 corresponds to an example of the 2 nd brake control in the present disclosure, and the three-phase inverter 21 corresponds to an example of the inverter in the present disclosure.

[ 2 nd embodiment ]

Hereinafter, embodiment 2 of the present disclosure will be described with reference to the drawings. In embodiment 2, a description will be given of a portion different from embodiment 1. The same reference numerals are assigned to the common components.

As shown in fig. 13, the electric working machine 1 of embodiment 2 differs from embodiment 1 in that the braking mode table BT is changed.

That is, in the 1 st braking period, the switching element Q2 is set to the on state and the switching elements Q4, Q6 are set to the off state. In the 2 nd braking period, the switching elements Q2, Q6 are set to the on state and the switching element Q4 is set to the off state.

In the 3 rd braking period, the switching element Q6 is set to the on state and the switching elements Q2, Q4 are set to the off state. In the 4 th braking period, the switching elements Q4, Q6 are set to the on state and the switching element Q2 is set to the off state.

In the 5 th braking period, the switching element Q4 is set to the on state and the switching elements Q2, Q6 are set to the off state. In the 6 th braking period, the switching elements Q2, Q4 are set to the on state and the switching element Q6 is set to the off state.

Fig. 14 is a timing chart showing changes in the hall sensor signals Hu, Hv, Hw, the states of the switching elements Q2, Q4, Q6, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw in the case where the off-trigger braking process is performed in embodiment 2.

As shown in fig. 14, the period from time t41 to time t42 is the 1 st braking period P1. The period from the time t42 to the time t43 is the 2 nd braking period P2. The period from the time t43 to the time t44 is the 3 rd braking period P3. The period from the time t44 to the time t45 is the 4 th braking period P4. The period from the time t45 to the time t46 is the 5 th braking period P5. The period from the time t46 to the time t47 is the 6 th braking period P6. The period from the time t47 to the time t48 is the 1 st braking period P1.

When the hall sensor signal Hu has an edge at time t41 and the 1 st braking period P1 starts, the switching element Q4 is switched from the on state to the off state after the off-trigger standby time Tbn has elapsed from time t 41.

When the hall sensor signal Hv has an edge at time t42 and the 2 nd braking period P2 starts, the switching element Q6 is switched from the off state to the on state after the off-trigger standby time Tbn has elapsed from time t 42.

When the hall sensor signal Hw has an edge at time t43 and the 3 rd braking period P3 starts, the switching element Q2 is switched from the on state to the off state after the off-trigger standby time Tbn has elapsed from time t 43.

When the hall sensor signal Hu has an edge at time t44 and the 4 th braking period P4 starts, the switching element Q4 is switched from the off state to the on state after the off-trigger standby time Tbn has elapsed from time t 44.

When the hall sensor signal Hv has an edge at time t45 and the 5 th braking period P5 starts, the switching element Q6 is switched from the on state to the off state after the off-trigger standby time Tbn has elapsed from time t 45.

When the hall sensor signal Hw has an edge at time t46 and the 6 th braking period P6 starts, the switching element Q2 is switched from the off state to the on state after the off-trigger standby time Tbn has elapsed from time t 46.

For example, in the 3 rd braking period P3, as shown in fig. 15, the switching elements Q1, Q3, Q5, and Q4 are in the off state, and the switching elements Q2, Q6 are in the on state. In this case, a U-phase current Iu from the ground to the motor 11 through the switching element Q2 and a W-phase current Iw from the motor 11 to the ground through the switching element Q6 are generated.

Fig. 16 is a timing chart showing changes in the hall sensor signals Hu, Hv, Hw, the states of the switching elements Q2, Q4, Q6, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw in the case where the kickback-time braking process is performed in embodiment 2.

As shown in fig. 16, the period from time t51 to time t52 is the 1 st braking period P1. The period from the time t52 to the time t53 is the 2 nd braking period P2. The period from the time t53 to the time t54 is the 3 rd braking period P3. The period from the time t54 to the time t55 is the 4 th braking period P4. The period from the time t55 to the time t56 is the 5 th braking period P5. The period from the time t56 to the time t57 is the 6 th braking period P6. The period from the time t57 to the time t58 is the 1 st braking period P1.

When the hall sensor signal Hu has an edge at time t51 and the 1 st braking period P1 starts, the switching element Q4 is switched from the on state to the off state after the kickback standby time Tba has elapsed from time t 51.

When the hall sensor signal Hv has an edge at time t52 and the 2 nd braking period P2 starts, the switching element Q6 is switched from the off state to the on state after the kickback standby time Tba has elapsed from time t 52.

When the hall sensor signal Hw has an edge at time t53 and the 3 rd braking period P3 starts, the switching element Q2 is switched from the on state to the off state after the kickback standby time Tba has elapsed from time t 53.

When the hall sensor signal Hu has an edge at time t54 and the 4 th braking period P4 starts, the switching element Q4 is switched from the off state to the on state after the kickback standby time Tba has elapsed from time t 54.

When the hall sensor signal Hv has an edge at time t55 and the 5 th braking period P5 starts, the switching element Q6 is switched from the on state to the off state after the recoil time standby time Tba has elapsed from time t 55.

When the hall sensor signal Hw has an edge at time t56 and the 6 th braking period P6 starts, the switching element Q2 is switched from the off state to the on state after the kickback standby time Tba has elapsed from time t 56.

In the electric working machine 1 configured as described above, the proportion of the two-phase braking period, which is the time during which braking force is generated with respect to the motor 11 by passing current through two of the three phases of the motor 11, which is a three-phase brushless motor, when the 1 st braking force is generated is larger than when the 2 nd braking force is generated. Further, the proportion of the off-braking period when the 2 nd braking force is generated, which is the time during which the braking force is generated by not passing current through all of the three phases of the motor 11, which is a three-phase brushless motor, is greater than that when the 1 st braking force is generated.

In the case where the off-time-triggered braking process is performed to generate the 2 nd braking force, as shown in fig. 14, in the 1 st braking period P1, the 3 rd braking period P3, and the 5 th braking period P5, phase currents always flow in two of the three phases. On the other hand, in the 2 nd brake period P2, the 4 th brake period P4, and the 6 th brake period P6, there is a full-phase non-energization period in which the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw do not flow.

In the case where the kick-time braking process is performed to generate the 1 st braking force, as shown in fig. 16, in the 1 st braking period P1, the 3 rd braking period P3, and the 5 th braking period P5, phase currents always flow in two of the three phases. On the other hand, in the 2 nd brake period P2, the 4 th brake period P4, and the 6 th brake period P6, the all-phase non-energization period is not present or is short even if the all-phase non-energization period is present.

That is, the proportion of the two-phase braking period in the case where the kickback-time braking process is executed is larger than the proportion of the two-phase braking period in the case where the off-trigger-time braking process is executed. Further, the proportion of the off-braking period in the case where the off-time trigger braking process is executed is larger than the proportion of the off-braking period in the case where the kickback-time braking process is executed.

As shown in fig. 17, the two-phase braking periods B31, B33, B35, B37 in the case where the kickback-time braking process is executed are longer than the two-phase braking periods B21, B23, B25, B27 in the case where the trigger off-time braking process is executed. Therefore, in the case where the kickback-time braking process is executed, the proportion of the two-phase braking period from the 1 st braking period P1 until the 6 th braking period P6 is larger than that in the case where the off-trigger-time braking process is executed.

Further, the off braking period B32 in the case where the kickback-time braking process is performed is an extremely short time for switching from the two-phase braking period B31 to the two-phase braking period B33. Similarly, the off braking period B34 is a very short time for switching from the two-phase braking period B33 to the two-phase braking period B35, and the off braking period B36 is a very short time for switching from the two-phase braking period B35 to the two-phase braking period B37.

Therefore, the off braking periods B22, B24, B26 in the case where the off-time trigger braking process is executed are longer than the off braking periods B32, B34, B36 in the case where the kick-back braking process is executed. Thus, when the off-time trigger braking process is executed, the proportion of the off-braking period from the 1 st braking period P1 to the 6 th braking period P6 is greater than that when the kickback-time trigger braking process is executed.

[ embodiment 3 ]

Hereinafter, embodiment 3 of the present disclosure will be described with reference to the drawings. In embodiment 3, the differences from embodiment 1 will be described. The same reference numerals are assigned to the common components.

The electric working machine 1 of embodiment 3 differs from that of embodiment 1 in that the working machine control process is changed.

As shown in fig. 18, the work machine control process according to embodiment 3 differs from that according to embodiment 1 in that the process of S70 is omitted and the process of S400 is added.

That is, in S40, in the case where kickback is occurring, the CPU22a shifts to S60.

Further, in S50, when the flip-flop 9 is in the off state, the CPU22a executes an idling process described later in S400, and shifts to S60.

Here, a description will be given of a procedure of the idling process executed in S400.

If the idling process is executed, as shown in fig. 19, the CPU22a first sets the switching elements Q1 to Q6 to the off state in S410. Then, the CPU22a determines in S420 whether or not the motor rotation speed is equal to or less than a preset standby rotation speed Je.

Here, when the motor rotation speed exceeds the standby rotation speed Je, the CPU22a proceeds to S410. On the other hand, when the motor rotation speed is equal to or less than the standby rotation speed Je, the CPU22a ends the idling process.

As shown in fig. 20, when the trigger signal is switched from the low level to the high level at time t61, the control unit 20 starts the drive process of the motor 11. Thus, the motor rotation speed gradually increases until time t62, and at this time t62, the motor rotation speed corresponds to the amount of engagement of the trigger 9.

Thereafter, when the trigger signal is switched from the high level to the low level at time t63, control section 20 starts the idling process. Thereby, the motor rotation speed is gradually reduced.

When the motor rotation speed becomes equal to or less than the standby rotation speed Je at time t64, the control unit 20 starts the off-time brake process. Thus, the motor rotation speed gradually decreases until time t65, and at time t65, the motor rotation speed is Orpm.

The electric working machine 1 configured as described above includes the motor 11, the trigger 9, and the control unit 20.

The processing of S40 and S60 generates a braking force for stopping the rotation of the motor 11 for the motor 11 immediately after the backlash is detected. The processes of S410, S420, and S60 generate the braking force after the motor rotation speed of the motor 11 reaches the standby rotation speed Je or less in the case where it is detected that the trigger 9 has changed from the operating state to the non-operating state.

When the kickback occurs as described above, the electric working machine 1 can reduce the time until the motor stops rotating by generating the braking force immediately after the kickback occurs. Further, when the user stops operating the trigger 9, the electric working machine 1 generates the braking force after the rotation speed of the motor 11 reaches the standby rotation speed Je or less, and thereby it is possible to suppress a sudden decrease in the motor rotation speed and reduce a reaction caused by the decrease in the motor rotation speed. As described above, the electric working machine 1 can reduce the time until the motor stops rotating when the kickback occurs, and can reduce the reaction to the user due to the decrease in the motor rotation speed when the user stops operating the trigger 9.

In the embodiment described above, S40 and S60 correspond to an example of the 5 th braking control in the present disclosure, S410, S420, and S60 correspond to an example of the 6 th braking control in the present disclosure, and the standby rotation speed Je corresponds to an example of the predetermined rotation speed in the present disclosure.

[ 4 th embodiment ]

Hereinafter, embodiment 4 of the present disclosure will be described with reference to the drawings. In embodiment 4, the differences from embodiment 3 will be described. The same reference numerals are assigned to the common components.

The electric working machine 1 according to embodiment 4 differs from embodiment 3 in that the idling process is changed.

Next, a procedure of the idling process of embodiment 4 will be described.

When the idling process of embodiment 4 is executed, as shown in fig. 21, the CPU22a first sets the switching elements Q1 to Q6 to the off state in S410. Then, the CPU22a determines in S460 whether or not a preset standby time Te has elapsed since the start of the off state of the switching elements Q1 to Q6.

Here, if the standby time Te has not elapsed, the CPU22a proceeds to S410. On the other hand, when the standby time Te has elapsed, the CPU22a ends the idling process.

As shown in fig. 22, when the trigger signal is switched from the low level to the high level at time t71, the control unit 20 starts the drive process of the motor 11. Thus, the motor rotation speed gradually increases until time t72, and at time t72, the motor rotation speed corresponds to the amount of engagement of the trigger 9.

Thereafter, when the trigger signal is switched from the high level to the low level at time t73, control section 20 starts the idling process. Thereby, the motor rotation speed is gradually reduced.

When the standby time Te has elapsed at time t74, the control unit 20 starts triggering the off-time brake process. Thus, the motor rotation speed gradually decreases until time t75, and at time t75, the motor rotation speed is Orpm.

The electric working machine 1 configured as described above includes the motor 11, the trigger 9, and the control unit 20.

The processing of S40 and S60 generates a braking force for stopping the rotation of the motor 11 for the motor 11 immediately after the backlash is detected. The processing of S410, S460, and S60 generates the braking force after the standby time Te has elapsed in the case where it is detected that the trigger 9 has changed from the operating state to the non-operating state.

When the kickback occurs as described above, the electric working machine 1 can reduce the time until the motor stops rotating by generating the braking force immediately after the kickback occurs. Further, when the user stops operating the trigger 9, the electric working machine 1 generates a braking force after the standby time Te has elapsed, and thus a sudden decrease in the motor rotation speed can be suppressed, and a reaction caused by the decrease in the motor rotation speed can be reduced. As described above, the electric working machine 1 can reduce the time until the motor stops rotating when the kickback occurs, and can reduce the reaction to the user due to the decrease in the motor rotation speed when the user stops operating the trigger 9.

In the above-described embodiment, S40 and S60 correspond to an example of the 3 rd brake control in the present disclosure, and S410, S460, and S60 correspond to an example of the 4 th brake control in the present disclosure.

While one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications can be made.

For example, in the above-described embodiment, the motor rotation angles at which the on states and the off states of the switching elements Q1 to Q6 are switched are set to be different between the case where the 1 st braking force is generated and the case where the 2 nd braking force is generated. However, the 1 st braking force may be generated using at least three-phase short-circuit braking, and the 2 nd braking force may be generated using at least two-phase short-circuit braking.

The three-phase short brake generates a braking force for the motor 11 by short-circuiting three terminals of the three-phase brushless motor. The three-phase short brake can generate a braking force by, for example, setting the switching elements Q1, Q3, Q5 to the off state and by setting the switching elements Q2, Q4, Q6 to the on state as shown in fig. 23.

The two-phase short-circuit brake generates a braking force for the motor 11 by short-circuiting between both terminals of the three-phase brushless motor. The two-phase short brake can generate a braking force by, for example, setting the switching elements Q1, Q3, Q5 to the off state and by setting two of the switching elements Q2, Q4, Q6 to the on state as shown in fig. 9.

The technique of the present disclosure can be applied to various electric working machines such as a grinder and a chain saw.

The plurality of functions of one constituent element in the above-described embodiments may be realized by a plurality of constituent elements, or one function of one constituent element may be realized by a plurality of constituent elements. Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to the configuration of the above other embodiment, or at least a part of the configuration of the above embodiment may be replaced with the configuration of the above other embodiment.

The present disclosure can be implemented in various forms other than the electric working machine 1 described above, such as a program for causing a computer to function as the control unit 20, a non-transitory tangible recording medium such as a semiconductor memory in which the program is recorded, a tool control method, and the like.

Description of the reference numerals

1 … electric working machine; 9 … trigger; 11 … a motor; 20 … control unit