Electric Impact Wrench Torque Control for Rebound Durability
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Solution Overview
Problem
Electric impact wrenches with rebound impact mechanisms face issues of rapid motor deterioration due to frequent direction changes, leading to vibration and reduced durability, especially when used with electric motors.
Innovation Solution
Implementing a torque-regulated power supply system for the electric motor, using a multi-phase synchronous motor with vector type control, which maintains constant electromagnetic torque during screwing or unscrewing operations, including during the rebound phase, to prevent overcurrent and motor degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rebound impact mechanism is used in an electric impact wrench, then the tool achieves compact size and high impact force, but the motor deteriorates rapidly due to frequent direction changes
Solution Approach 1:
The patent extracts the rebound mechanism from the motor system by introducing a separate impact mechanism that decouples the motor's rotational motion from the impact generation. The motor continuously rotates in one direction, while the impact mechanism (including hammers, anvils, and elastic elements) generates impacts independently, eliminating the harmful reverse rotation that caused motor deterioration.
Solution Approach 2:
The patent introduces an intermediary impact mechanism between the motor and the output shaft. This mechanism includes elastic elements (springs or rubber components) that store and release energy to generate impacts, acting as a mediator that converts continuous motor rotation into periodic impact forces without requiring the motor to reverse direction.
2Force
If a rebound impact mechanism causes frequent motor direction changes, then high impact torque is generated, but vibration increases and user comfort decreases
Solution Approach 1:
The patent separates the vibration-generating rebound motion from the motor by extracting it into an independent impact mechanism. The motor maintains steady unidirectional rotation, while the impact mechanism absorbs and manages the vibratory forces through its elastic elements and hammer-anvil collision design, reducing transmitted vibration to the user.
Solution Approach 2:
The patent incorporates elastic cushioning elements (springs or rubber components) in the impact mechanism that absorb and dampen vibration forces before they reach the motor housing and user interface. These elements provide beforehand cushioning that reduces the transmission of harmful vibrations while maintaining impact effectiveness.
3Force
If the motor is allowed to rebound in reverse direction, then the impact mechanism generates sufficient force, but the motor operates in unstable conditions leading to rapid deterioration
Solution Approach 1:
The patent extracts the unstable reverse-motion requirement from the motor system entirely. The motor operates stably in continuous unidirectional rotation, while the impact mechanism (with its hammers, anvils, and elastic storage elements) independently generates the necessary impact forces through controlled collisions, eliminating the stability-deteriorating reverse rotation.
Solution Approach 2:
The patent introduces dynamic elements (elastic springs or rubber components) into the impact mechanism that allow flexible energy storage and release. These dynamic elements enable the impact mechanism to generate high forces through controlled deformation and rebound without requiring the motor itself to undergo unstable direction changes, maintaining motor operational stability.
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 solution enhances the durability and reduces vibrations in electric impact wrenches by maintaining a stable motor operation, similar to pneumatic tools, while preserving the motor's integrity and improving user comfort.
Implementation Method 1
a multi-phase synchronous motor with vector type control, which maintains constant electromagnetic torque during screwing or unscrewing operations
Implementation Method 2
a kinematic chain incorporating an elastic element capable of deforming to allow the rotor of the motor to continue rotating when, at each impact, the rotation of the output shaft of the impact wrench is greatly decelerated
Data Source
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AI summary
The present invention relates to an impact wrench comprising: - an electric motor including a rotor and a stator; - a rebounding impact mechanism; - means for controlling the power supply of said motor including means for regulating the current supplied to said motor; said rotor of said motor being directly connected to said impact mechanism. According to the invention, said means for controlling the power supply of said motor are configured to deliver to said regulating means, during a tightening or loosening operation, a current supply command to the motor inducing the generation by said motor of a predetermined electromagnetic torque, said motor being a permanent magnet synchronous multi-phase motor and said means for controlling the power supply of said motor using vector control.