Working machine and method of braking driving device of working machine

Patent metadata

Field	Value
Publication number	US-11039570-B2
Application number	US-201715724438-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 5, 2016
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A working machine according to one aspect of the present disclosure comprises an operating device, a working tool, a driving device, a braking device, a detection device, and a change device. The detection device detects a mode of an operation performed on the operating device. The change device changes a brake control to be performed by the braking device according to the mode detected by the detection device.

First claim

What is claimed is:

1. A working machine comprising:
an operating device configured to be operated by an operator of the working machine;
a working tool configured to perform a work using a rotational force;
a driving device configured to rotationally drive the working tool in response to an on operation performed on the operating device;
a braking device configured to perform a brake control that reduces a rotational speed of the driving device in response to an off operation in which non-driving of the driving device is commanded to the driving device;
a detection device configured to detect a mode of an operation performed on the operating device, the operation corresponding to the off operation or the on operation; and
a change device configured to change the brake control according to the mode detected by the detection device,
wherein the detection device is configured to determine that the on operation is performed on the operating device,
wherein the detection device is configured to detect, as the mode, a duration of the on operation in which driving of the driving device is commanded to the driving device, based on determining that the on operation is performed on the operating device,
wherein the change device is configured to change the brake control to a normal brake control based on the duration of the on operation detected by the detection device being greater than a threshold on time that has been preset, the normal brake control using a normal braking force that has been preset,
wherein the detection device is further configured to detect a duration of the off operation as the mode, and
wherein the change device is configured to, in a case where the duration of the on operation detected by the detection device is equal to or shorter than the threshold of time, (i) change the brake control to the normal brake control based on the duration of the off operation detected by the detection device being greater than a threshold off time that has been preset, and (ii) change the brake control to a weak brake control based on the duration of the off operation being equal to or smaller than the threshold off time, the weak brake control using a braking force weaker than the normal braking force.

2. The working machine according to claim 1 ,
wherein the threshold off time is set to be longer than a standard duration of the off operation for an intermittent operation, the intermittent operation corresponding to the on operation and the off operation being repeated alternately to control a rotational speed of the working tool.

3. The working machine according to claim 1 ,
wherein the threshold on time is set to be longer than a standard duration of the on operation for an intermittent operation, the intermittent operation corresponding to the on operation and the off operation being repeated alternately to control a rotational speed of the working tool.

4. The working machine according to claim 1 ,
wherein the driving device comprises an electric motor.

5. The working machine according to claim 4 ,
wherein the brake control uses a free-run state that opens an excitation current path to the electric motor and/or short-circuit braking that short-circuits the excitation current path to the electric motor.

6. A method of braking a driving device of a working machine, the method comprising:
performing, by a braking device of the working machine, a brake control that reduces a rotational speed of the driving device in response to an off operation in which non-driving of the driving device is commanded to the driving device;
detecting, by a detection device of the working machine, a mode of an operation performed on an operating device of the working machine, the operation corresponding to the off operation or an on operation; and
changing, by a change device of the working machine, the brake control according to the mode detected,
wherein the method further comprises determining, by the detection device, that the on operation is performed on the operating device,
wherein the method further comprises detecting, by the detection device, as the mode, a duration of the on operation in which driving of the driving device is commanded to the driving device, based on determining that the on operation is performed on the operating device,
wherein the method further comprises changing, by the change device, the brake control to a normal brake control based on the duration of the on operation detected being greater than a threshold on time that has been preset, the normal brake control using a normal braking force that has been preset,
wherein the method further comprises detecting, by the detection device, a duration of the off operation as the mode, and
wherein the method further comprises, in a case where the duration of the on operation detected by the detection device is equal to or shorter than the threshold on time, (i) changing, by the change device, the brake control on the normal brake control based on the duration of the off operation detected by the detection device being greater than a threshold off time that has been preset, and (ii) changing, by the change device, the brake control to a weak brake control based on the duration of the off operation being equal to or smaller than the threshold off time, the weak brake control using a braking force weaker than the normal braking force.

7. A working machine comprising:
an operating device configured to be operated by an operator of the working machine;
a working tool configured to perform a work using a rotational force;
a driving device configured to rotationally drive the working tool in response to an on operation performed on the operating device;
a braking device configured to perform a brake control that reduces a rotational speed of the driving device in response to an off operation in which non-driving of the driving device is commanded to the driving device;
a control circuit configured to detect a mode of an operation performed on the operating device, the operation corresponding to the off operation or the on operation, and configured to change the brake control according to the mode detected,
wherein the control circuit is configured to determine that the on operation is performed on the operating device,
wherein the control circuit is configured to detect, as the mode, a duration of the on operation in which driving of the driving device is commanded to the driving device, based on determining that the on operation is performed on the operating device,
wherein the control circuit is configured to change the brake control to a normal brake control based on the duration of the on operation detected by the control circuit being greater than a threshold on time that has been preset, the normal brake control using a normal braking force that has been preset,
wherein the control circuit is further configured to detect a duration of the off operation as the mode, and
wherein the control circuit is further configured to, in a case where the duration of the on operation detected by the detection device is equal to or shorter than the threshold on time, (i) change the brake control to the normal brake control based on the duration of the off operation detected by the detection device being greater than a threshold off time that has been preset, and (ii) change the brake control to a weak brake control based on the duration of the off operation being equal to or smaller than the threshold off time, the weak brake control using a braking force weaker than the normal braking force.

Assignees

• Makita Corp

Inventors

• Takahashi Yuji
• Takeda Kouichi

Classifications

• A01D34/4167

  Protection devices · CPC title

• A01D34/828

  Safety devices · CPC title

• A01D34/006 Primary

  Control or measuring arrangements · CPC title

• A01D34/90

  for carrying by the operator · CPC title

• A01D34/412 Primary

  having rotating cutters · CPC title