Electric Pulse Tool Rotor Speed Control for Defined Torque Pulses
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Solution Overview
Problem
Existing electric pulse tools lack well-defined pulses, resulting in variability in the number of pulses required to achieve a target torque, which affects the efficiency and ergonomics of tightening operations.
Innovation Solution
The electric pulse tool controls the speed of the rotor until a play in the gear arrangement is closed, allowing for more defined pulses by delivering torque in a series of controlled pulses, utilizing a processor and sensor to manage the motor speed and current intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pulsed current is fed to the electric motor to reduce reaction force, then operator ergonomics is improved, but pulse definition becomes poor resulting in variability in number of pulses required
Solution Approach 1:
The patent changes the control parameter from simple pulsed current application to controlled rotor speed with specific timing relative to gear play closure. By controlling the rotor speed parameter and the timing of pulse delivery, the system achieves both reduced reaction force and well-defined pulses with consistent kinetic energy transfer.
Solution Approach 2:
The patent employs feedback by monitoring rotor speed and gear arrangement state to determine the optimal timing for pulse delivery. The control system adjusts the pulsed current based on feedback about when the gear play is closed, ensuring consistent pulse definition and kinetic energy transfer while maintaining reduced reaction force.
2Force
If pulsed torque is delivered to reduce reaction force, then operator reaction force is reduced, but consistency of torque delivery becomes poor
Solution Approach 1:
The patent applies preliminary action by controlling the rotor speed before the gear play is closed, ensuring that the pulsed torque is delivered at the optimal moment when the gear arrangement is ready to transmit force efficiently. This preliminary speed control ensures consistent kinetic energy transfer and torque consistency while maintaining reduced reaction force.
3Device complexity
If simple pulsed current is applied to the motor, then device complexity is low, but pulse definition and kinetic energy consistency are poor
Solution Approach 1:
The patent replaces simple electrical pulse control with a more sophisticated control mechanism that monitors and controls rotor speed and gear state. This substitution of control methodology (from simple electrical timing to mechanical state-aware control) achieves consistent kinetic energy transfer while maintaining reasonable device complexity through efficient sensor and controller integration.
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
This approach ensures consistent kinetic energy transfer with each pulse, reducing operator reaction force and improving the speed and accuracy of tightening operations.
Implementation Method 1
an electric motor with a rotor and a gear arrangement adapted to drive an output shaft
Implementation Method 2
a gear arrangement adapted to drive an output shaft... control the speed of the rotor until a play in the gear arrangement is determined to be closed
Data Source
AI summary
An electric pulse tool delivers torque in pulses on an output shaft of the electric pulse tool. The electric pulse tool includes an electric motor with a rotor and a gear arrangement adapted to drive the output shaft. The electrical pulse tool is operative, for each period, to control the speed of the rotor until a play in the gear arrangement is determined to be closed and the gear arrangement starts to move the output shaft.