Electric working machine

Patent metadata

Field	Value
Publication number	US-12051986-B2
Application number	US-201916715813-A
Country	US
Kind code	B2
Filing date	Dec 16, 2019
Priority date	Dec 26, 2018
Publication date	Jul 30, 2024
Grant date	Jul 30, 2024

Abstract

An electric working machine in one aspect of the present disclosure includes a motor, an information output circuit, a control circuit, and a drive stop circuit. The information output circuit outputs state information that indicates a state of the electric working machine. The control circuit executes a motor control process in accordance with a computer program. The drive stop circuit executes a motor stop operation. The motor stop operation includes disabling a permission to drive the motor by the control circuit to stop the motor in response to the state information indicating that the motor should be stopped. The motor stop operation is implemented by hardware.

First claim

What is claimed is:

1. An electric working machine comprising:
a motor configured to generate a rotational driving force;
a motor drive circuit configured (i) to receive a drive command and (ii) to supply electric power to the motor to drive the motor in response to having received or receiving the drive command;
a trigger configured to be operated by a user of the electric working machine;
an output tool configured to be driven with the rotational driving force;
a first information output circuit configured to output first state information that includes a state of the electric working machine;
a control circuit configured (i) to execute a motor control process in accordance with a computer program and (ii) to receive the first state information from the first information output circuit, the motor control process including outputting the drive command in accordance with the first state information indicating that the motor is permitted to be driven;
a first signal output circuit distinct from the first information output circuit, the first signal output circuit being hardwired (i) to receive the first state information from the first information output circuit, and (ii) to output a first signal in response to the first state information indicating that the motor should be stopped; and
a drive stop circuit that is hardwired (i) to receive the first signal from the first signal output circuit and (ii) to output an interruption signal in response to having received or receiving the first signal, wherein the interruption signal disables the drive command.

2. The electric working machine according to claim 1 , wherein
the first state information indicates a physical quantity that indicates the state of the electric working machine,
the first information output circuit is configured (i) to detect the physical quantity and (ii) to output the first state information that includes the physical quantity detected by the first information output circuit,
the motor control process includes outputting the drive command in response to the physical quantity included in the first state information being within a first permitted range and
the first signal output circuit being configured to output the first signal in response to the physical quantity included in the first state information being outside a second permitted range.

3. The electric working machine according to claim 2 ,
wherein the physical quantity includes a value of electric current supplied to the motor.

4. The electric working machine according to claim 2 , further comprising
a battery configured to supply electric power to drive the motor,
wherein the physical quantity includes a value of voltage of the battery.

5. The electric working machine according to claim 2 , further comprising:
a battery configured to supply electric power to drive the motor, wherein:
the motor drive circuit is configured to (i) receive the electric power from the battery and (ii) supply the electric power to the motor via the motor drive circuit, and
the physical quantity includes a temperature of the motor drive circuit.

6. The electric working machine according to claim 2 ,
wherein the second permitted range includes the first permitted range, and is wider than the first permitted range.

7. The electric working machine according to claim 1 , further comprising:
a drive line configured to transmit the drive command from the control circuit to the motor drive circuit, wherein the drive stop circuit includes:
an interruption signal output circuit configured (i) to receive the first signal from the first signal output circuit and (ii) to output the interruption signal in response to having received or receiving the first signal; and
an interruption switch (a) on the drive line and (b) configured (i) to complete or interrupt the drive line, (ii) to receive the interruption signal, and (iii) to interrupt the drive line based on having received or receiving the interruption signal.

8. The electric working machine according to claim 7 ,
wherein the control circuit is configured (i) to receive the interruption signal and (ii) to stop output of the drive command in response to having received or receiving the interruption signal.

9. The electric working machine according to claim 7 , further comprises:
a second information output circuit configured to output second state information that includes the state of the electric working machine; and
a second signal output circuit that is hardwired (i) to receive the second state information from the second information output circuit and (ii) to output a second signal in response to the second state information indicating that the motor should be stopped,
wherein the interruption signal output circuit is configured (i) to receive the first signal from the first signal output circuit, (ii) to receive the second signal from the second signal output circuit, and (iii) to output the interruption signal in response to having received or receiving the first signal and/or the second signal.

10. The electric working machine according to claim 9 ,
wherein the interruption signal output circuit includes an OR gate configured to receive the first signal and the second signal.

11. The electric working machine according to claim 1 , further comprising:
a second information output circuit configured to output second state information that includes the state of the electric working machine; and
a second signal output circuit that is hardwired (i) to receive the second state information from the second information output circuit, and (ii) to output a second signal in response to the second state information indicating that the motor should be stopped.

12. The electric working machine according to claim 11 , wherein:
the control circuit is further configured to receive the second state information from the second information output circuit, and
the motor control process includes outputting the drive command in accordance with the first state information and the second state information both indicating that the motor is permitted to be driven.

13. The electric working machine according to claim 1 , wherein:
the trigger is configured to be on-operated or off-operated by the user of the electric working machine,
the electric working machine further includes a trigger detection circuit configured to output trigger determination information indicating which of the on-operation and the off-operation is performed, and
the drive stop circuit is configured to receive the trigger determination information.

14. The electric working machine according to claim 13 ,
wherein the drive stop circuit is configured to execute:
a first operation of disabling the drive command from the control circuit to stop the motor, in response to (i) having received or receiving the trigger determination information indicating the on-operation and (ii) having received or receiving the first signal;
a second operation of continuously stopping the motor, in response to (i) maintaining the trigger determination information indicating the on-operation and (ii) failing to receive the first signal, during execution of the first operation; and
a third operation of stopping disabling of the drive command, in response to having received the trigger determination information indicating the off-operation, during execution of the second operation.

15. The electric working machine according to claim 1 , wherein:
the first information output circuit includes a first terminal and a second terminal;
the first terminal is coupled to a ground line;
the seco

Assignees

• Makita Corp

Inventors

• Nakamoto Akihiro
• Suzuki Hitoshi

Classifications

• H02J7/663

  using battery or load disconnect circuits (H02J9/002 takes precedence) · CPC title

• H02J7/80

  including monitoring or indicating arrangements · CPC title

• H02J7/64

  against overvoltage · CPC title

• H02P29/027

  the fault being an over-current · CPC title

• A01D34/90

  for carrying by the operator · CPC title