Electric tool

Patent metadata

Field	Value
Publication number	US-2020130156-A1
Application number	US-201916663996-A
Country	US
Kind code	A1
Filing date	Oct 25, 2019
Priority date	Oct 26, 2018
Publication date	Apr 30, 2020
Grant date	—

Abstract

An electric tool includes a motor, an operation part provided to be operable by a user, a motor drive control unit configured to perform control of driving the motor in response to the operation part being operated, a temperature sensor, and a temperature determination unit configured to determine overheating of the motor. The temperature determination unit is configured to estimate a temperature of the motor based on a drive situation of the motor and a detection result of the temperature sensor, and to determine the overheating of the motor based on the estimated temperature.

First claim

1 . An electric tool comprising:
a motor; an operation part provided to be operable by a user; a motor drive control unit configured to perform control of driving the motor in response to the operation part being operated; a temperature sensor; and a temperature determination unit configured to determine overheating of the motor, wherein the temperature determination unit is configured to estimate a temperature of the motor based on a drive situation of the motor and a detection result of the temperature sensor, and to determine the overheating of the motor based on the estimated temperature.

2 . The electric tool according to claim 1 ,
wherein the motor drive control unit is configured to limit an output of the motor when the operation part is operated in a state where the temperature determination unit detects the overheating of the motor.

3 . The electric tool according to claim 1 ,
wherein the temperature determination unit is configured to estimate the temperature of the motor at least using the drive situation of the motor for a predetermined fixed period and a change in temperature detected by the temperature sensor for the fixed period.

4 . The electric tool according to claim 3 ,
wherein the temperature determination unit is configured to estimate the temperature of the motor at least using a drive time period of the motor for the predetermined fixed period and the change in temperature detected by the temperature sensor for the fixed period.

5 . The electric tool according to claim 1 , further comprising:
a driver configured to be driven by the motor and to strike out a fastener from an ejecting port provided at a tip end of the tool, wherein the temperature determination unit is configured to calculate an operation pace based on a number of drive times of the driver, and to estimate the temperature of the motor based on the operation pace and the detection result of the temperature sensor.

6 . An electric tool comprising:
a motor; an operation part provided to be operable by a user; a motor drive control unit configured to perform control of driving the motor in response to the operation part being operated; a temperature sensor; and a temperature determination unit configured to determine overheating of the motor, wherein the temperature determination unit is configured to determine an overheated state of the motor by comparing a determination threshold value which varies depending on a drive situation of the motor for a predetermined fixed period, and an output of the temperature sensor.

7 . The electric tool according to claim 6 ,
wherein the temperature determination unit is configured to determine a determination threshold value for determining the overheated state of the motor at least using the drive situation of the motor for the predetermined fixed period and the change in temperature detected by the temperature sensor for the fixed period.

8 . An electric tool comprising:
a motor; an operation part provided to be operable by a user; and a control device including:
a motor drive control unit configured to perform control of driving the motor in response to the operation part being operated; and
a temperature determination unit configured to compare a temperature of a heat generating part with a predetermined threshold value, wherein a first threshold value and a second threshold value greater than the first threshold value are set as the predetermined threshold value,
wherein the control device is configured to:
notify a user of an increase in temperature when the temperature determination unit determines that the temperature of the heat generating part is higher than the first threshold value, and
limit an output of the motor when the temperature determination unit determines that the temperature of the heat generating part is higher than the second threshold value.

9 . The electric tool according to claim 8 ,
wherein the control device is configured to perform the notification by changing a drive mode of the motor.

10 . The electric tool according to claim 9 , further comprising:
a driver provided to be slidable toward an ejecting port provided at a tip end of the tool to strike out a fastener from the ejecting port; a plunger to which the driver is coupled; a plunger urging member configured to urge the plunger toward the ejecting port; and a drive mechanism configured to move the plunger using the motor as a power source to accumulate an urging force in the plunger urging member, wherein the control device is configured to control the drive mechanism such that a stop position of the plunger is different depending on whether to perform the notification.

11 . The electric tool according to claim 10 ,
wherein the control device is configured to control the drive mechanism such that:
when not performing the notification, the plunger is moved and stopped in a normal standby position where a predetermined urging force is accumulated in the plunger urging member; and
when performing the notification, the plunger is moved and stopped in a standby position for notification where the urging force accumulated in the plunger urging member is less than in the normal standby position.

12 . The electric tool according to claim 9 ,
wherein the control device is configured to perform the notification by delaying a time period after the operation part is operated until the motor is driven.

13 . The electric tool according to claim 9 ,
wherein the control device is configured to perform the notification by reducing a rotation speed of the motor as compared to a case where the notification is not performed.

Assignees

• Max Co Ltd

Inventors

• Takeuchi Katsuki
• SUTO Kohei
• Ando Teruaki

Classifications

• B25C1/06

  operated by electric power · CPC title

• H02P29/64

  Controlling or determining the temperature of the winding · CPC title

• B25F5/008 Primary

  Cooling means · CPC title

• B25C1/008 Primary

  Safety devices · CPC title

• H02P29/60

  Controlling or determining the temperature of the motor or of the drive (H02P29/02 takes precedence) · CPC title