Electric Power Tool Motor Control Circuit for Load Limiting
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Solution Overview
Problem
Rotary impact tools are prone to mechanical part damage due to excessive torque and load, which can lead to equipment failure and reduced tool lifespan.
Innovation Solution
Incorporating a control circuit that limits the motor output when a preset load condition is met, reducing the torque applied to mechanical parts and preventing continuous high-load application, thereby preventing damage to the tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor output is not limited under high load conditions, then the tool can maintain high power and productivity, but mechanical parts such as planetary gears, sun gears, and internal gears may be damaged due to excessive torque
Solution Approach 1:
The control circuit continuously monitors the load applied to the motor and provides feedback control. When the load exceeds a predetermined threshold, the control circuit automatically limits the motor output to prevent mechanical part damage. This closed-loop feedback mechanism resolves the contradiction by dynamically adjusting power output based on real-time load conditions while maintaining high power capability when loads are within safe limits.
Solution Approach 2:
The motor output is made dynamic rather than static. The control circuit enables the motor output to change based on operating conditions - maintaining high power output when loads are normal, but automatically reducing output when excessive load is detected. This dynamic adjustment resolves the contradiction between maintaining high power and preventing mechanical damage.
2Productivity
If the motor operates continuously under high load, then productivity is maintained, but damages to the electric power tool occur due to excessive torque on mechanical parts
Solution Approach 1:
The control circuit uses continuous feedback from load monitoring to prevent productivity loss. When excessive load is detected, the system automatically adjusts motor output to safe levels, preventing mechanical damage that would otherwise require tool repair or replacement. This resolves the contradiction by maintaining productivity through preventive control rather than allowing damage accumulation.
Solution Approach 2:
The control circuit provides beforehand protection by limiting motor output before mechanical damage can occur. The predetermined load threshold acts as a safety buffer, and the control circuit engages protective action in advance when approaching dangerous load levels, preventing tool damage before it happens and ensuring long-term operational reliability.
Data Source
AI summary
An electric power tool in one aspect of the present disclosure includes a motor, an impact mechanism, and a control circuit. The control circuit executes a motor control process. The motor control process includes limiting an output of the motor in response to establishment of a preset condition. The preset condition is based on a load applied to the motor.