Impact Wrench Motor Control Using Drive Angle Feedback
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Solution Overview
Problem
Existing power tools with impact mechanisms lack efficient control mechanisms to optimize motor speed based on impact dynamics, leading to suboptimal performance and potential tool damage during tasks like driving anchors into concrete.
Innovation Solution
A power tool with a brushless DC motor, impact mechanism, and position sensor that calculates the drive angle of an output drive device based on impact positions, controlling the motor speed to adjust torque delivery according to the impact dynamics, thereby optimizing tool performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If motor speed is increased to improve task efficiency, then productivity increases, but tool wear and potential damage increases
Solution Approach 1:
The system dynamically adjusts motor speed based on real-time impact detection. The controller monitors impact events and modifies motor operating parameters on-the-fly, transitioning from static speed control to dynamic adaptation, thereby optimizing productivity while preventing excessive wear during high-stress conditions
Solution Approach 2:
The system implements feedback control by detecting impact events and using this information to adjust motor speed. The controller receives feedback from impact detection and modifies motor operation accordingly, creating a closed-loop system that balances productivity and tool protection
2Reliability
If motor speed is reduced to reduce tool wear, then reliability improves, but task efficiency decreases
Solution Approach 1:
Rather than maintaining a constantly reduced speed, the system dynamically varies motor speed based on operational conditions. During normal operation, high speed maintains productivity; during detected impact events, speed is temporarily reduced to protect the tool, then restored afterward
3Device complexity
If fixed torque delivery is used to simplify control, then device complexity is reduced, but performance optimization is limited
Solution Approach 1:
The system uses impact detection feedback to adjust torque delivery dynamically. The controller monitors impact events and modifies motor operation accordingly, enabling adaptive torque control that optimizes performance for different material conditions without requiring complex pre-programming
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise control of motor speed based on impact dynamics, improving task efficiency and reducing tool wear by adjusting torque delivery in real-time, ensuring optimal performance across varying material conditions.
Implementation Method 1
a brushless direct current (DC) motor within the housing. The brushless DC motor includes a rotor and a stator, wherein the rotor is coupled to a motor shaft to produce a rotational output
Implementation Method 2
a position sensor that senses a position of the rotor
Implementation Method 3
The impact mechanism includes a hammer coupled to the motor shaft, and an anvil that receives impacts from the hammer
Data Source
AI summary
A power tool with an impact mechanism and that is controlled based on a drive angle from impacting. The power tool includes a housing, a brushless direct current (DC) motor within the housing, an impact mechanism, and an output drive device. The brushless DC motor includes a rotor coupled to a motor shaft to produce a rotational output. The impact mechanism includes a hammer coupled to the motor shaft, and an anvil that receives impacts from the hammer and drives an output device. The power tool further includes a position sensor that senses a position of the rotor and a controller coupled to the position sensor. The controller detects an impact of the impact mechanism, calculates a drive angle of the anvil caused by the impact based on output from the position sensor, and controls the brushless DC motor based on the drive angle.