ELECTRIC TOOL AND CONTROLLING METHOD THEREOF

• US 20140338939A1
• Filed: 04/29/2014
• Published: 11/20/2014
• Est. Priority Date: 05/20/2013
• Status: Active Grant

• Current Assignee: Chervon (HK) Limited (Chervon Holdings Limited)
• Original Assignee: Chervon (HK) Limited (Chervon Holdings Limited)
• Inventors: Shi, Pingbo
• Granted Patent: US 9,707,671 B2
• Time in Patent Office: Days
• US Class Current: 173/1
• CPC Class Codes: B25B 23/1405 for impact wrenches or screwdrivers
• CPC Class Codes: B25B 23/147 specially adapted for electrically operated wrenches or screwdrivers
• CPC Class Codes: H02P 29/032 Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
• CPC Class Codes: H02P 29/68 based on the temperature of a drive component or a semiconductor component

Abstract

An electric tool has a motor, an implementing member driven by the motor for driving a working element and a controlling circuit for controlling the electric tool. The controlling circuit includes a current detecting module for detecting the current flowing through the motor; a microprocessor for memorizing and storing a current value; an user interface module for an user to select working modes, and the working modes at least comprising a learning mode for recording the current value after the implementing member has driven the working element and a constant torque mode for driving other working elements having the same size based on the recorded current value; and a driving module for driving or stopping the torque output of the motor. The electric tool can achieve the function of electronic clutch so as to drive screws having the same size with substantially the same effect. The present disclosure also discloses a controlling method by using the above controlling circuit.

Claims

1. An electric tool, comprising:

a motor;

an implementing member driven by the motor for driving a working element; and

a controlling circuit for controlling the electric tool, wherein the controlling circuit comprises a current detecting module for detecting current flowing through the motor;

a microprocessor for memorizing and storing a current value;

an user interface module connected to the microprocessor for a user to select working modes, the working modes at least comprising a learning mode for recording the current value when the implementing member has driven the working element and a constant torque mode for driving other working elements having the same size based on the recorded current value; and

a driving module controlled by the microprocessor for driving or stopping a torque output of the motor.

2. The electric tool according to claim 1, wherein the electric tool further comprises a power module for providing power to the microprocessor and the driving module and a current signal processing module for processing the current value detected by the current detecting module, and the microprocessor is configured to memorize and store the current value processed by the current signal processing module.

3. The electric tool according to claim 1, wherein the working modes further comprise a constant torque transitory invalidation mode for driving other working elements having different sizes from the above size.

4. The electric tool according to claim 1, wherein the electric tool further comprises a forward and reversal rotation signal collecting module, and the working modes further comprise a reversal rotation high-efficiency mode in which the motor outputs maximum torque, and wherein the working modes enters the reversal rotation high-efficiency mode when the motor is rotated reversely no matter whether the microprocessor has memorized and stored the current value.

5. The electric tool according to claim 1, wherein the electric tool comprises a trigger for driving or stopping the motor, and the microprocessor is configured to compensate the current value detected by the current detecting module or the current value processed by the current signal processing module with a compensation coefficient inversely proportional to a pressing amount of the trigger.

6. The electric tool according to claim 1, wherein the electric tool comprises a battery pack and a circuit board having a switching element, and the controlling circuit further comprises a detecting module for detecting temperature, current and voltage of the battery pack or temperature of the switching element, and wherein the torque output of the motor is stopped when the temperature of the battery pack is higher than a preset value, or the torque output of the motor is stopped when the current value in the battery pack is higher than a preset value, or the torque output of the motor is stopped when the voltage in the battery pack is lower than a preset value, or the torque output of the motor is stopped when the temperature of the switching element is higher than a preset value.

7. The electric tool according to claim 3, wherein the electric tool comprises an user interface comprising at least one operating key for selecting the working modes, a first signal indicating light for indicating whether the learning mode is selected, a second indicating light for indicating whether the constant torque mode is selected, and a third indicating light for indicating whether the constant torque transitory invalidation mode is selected.

8. A method for controlling an electric tool comprising a motor and an implementing member driven by the motor for driving a working element, the controlling method comprising the steps of:

detecting current flowing through the motor by a current detecting module;

memorizing and storing a current value by a microprocessor;

selecting working modes by an user interface module, wherein the working modes comprise at least a learning mode for recording the current value after the implementing member has driven the working element and a constant torque mode for driving other working elements having the same size based on the recorded current value; and

driving or stopping a torque output of the motor by a driving module controlled by the microprocessor according to the selected working mode.

9. The method according to claim 8, wherein the controlling method further comprises the steps of processing the current value detected by the current detecting module via a current signal processing module and providing power to the microprocessor and the driving module via a power module, and wherein the microprocessor can memorize and store the current value processed by the current signal processing module.

10. The method according to claim 8, wherein the working modes further comprise a constant torque transitory invalidation mode for driving other working elements having the different sizes from the above size, and wherein the controlling method further comprises the step of selecting the constant torque transitory invalidation mode by the user interface.

11. The method according to claim 8, wherein the working modes further comprise a reversal rotation high-efficiency mode in which the motor outputs the maximum torque, and the controlling method further comprises the step of collecting the forward and reversal rotation signals of the motor by a forward and reversal rotation signal collecting module, and wherein the microprocessor controls the electric tool to enter the reversal rotation high-efficiency mode when the motor is rotated reversely no matter whether the microprocessor has memorized and stored the current value.

12. The method according to claim 8, wherein the electric tool comprises a trigger for driving or stopping the torque output of the motor, and wherein the controlling method further comprises the step of compensating for the current value detected by the current detecting module or the current value processed by the current signal processing module with a compensation coefficient inversely proportional to a pressing amount of the trigger via the microprocessor.

13. The method according to claim 8, wherein the electric tool comprises a battery pack and a circuit board having a switching element, and the controlling method further comprises the step of detecting the temperature, current and voltage of the battery pack or the temperature of the switching element by a detecting module, and wherein the torque output of the motor is stopped when the temperature of the battery pack is higher than a preset value, or the torque output of the motor is stopped when the current value in the battery pack is higher than a preset value, or the torque output of the motor is stopped when the voltage in the battery pack is lower than a preset value, or the torque output of the motor is stopped when the temperature of the switching element is higher than a preset value.