Impact Tool Shutdown Control Using Motor Commutation Cycles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing impact tools rely on user judgment to determine when fastening is complete, leading to potential damage to fasteners and workpieces due to inaccurate timing.
Innovation Solution
An impact tool with a controller that uses motor commutation cycle parameters to automatically detect the fastening state, limiting torque output and shutting down the motor when the fastener is fully secured, based on load parameters such as commutation cycles and their changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If user determines fastening completion by hand feeling, then operation simplicity is maintained, but fastening precision and reliability deteriorate
Solution Approach 1:
The patent replaces the mechanical hand-feeling detection method with an electronic control system that monitors motor current, commutation cycles, and impact mechanism parameters. The controller automatically determines fastening completion based on these electrical and mechanical parameters, substituting human sensory judgment with precise electronic sensing and control.
Solution Approach 2:
The patent implements a feedback control system where the controller continuously monitors motor running parameters (current, commutation cycles) and impact mechanism status, then uses this feedback information to automatically determine when fastening is complete and control the motor to shut down. This closed-loop feedback replaces the open-loop manual detection method.
2Productivity
If impact tool continuously outputs torque, then fastening speed is improved, but risk of over-tightening and workpiece damage increases
Solution Approach 1:
The patent performs preliminary detection of fastening state during the fastening process by monitoring motor parameters and impact mechanism status. The controller uses this preliminary information to predict when fastening will be complete, allowing the motor to shut down before excessive torque is applied, thus preventing over-tightening while maintaining high speed.
Solution Approach 2:
The patent uses real-time feedback from motor current detection and commutation cycle monitoring to automatically control motor shutdown. When the controller detects that fastening parameters meet preset conditions, it immediately stops torque output, creating a self-regulating system that prevents workpiece damage while maintaining efficient fastening speed.
3Device complexity
If impact tool lacks automatic detection mechanism, then device complexity is reduced, but fastening reliability deteriorates
Solution Approach 1:
The patent enables the impact tool to self-determine fastening completion using its own existing operational parameters (motor current, commutation cycles, impact frequency). The controller utilizes data already generated during normal operation without requiring external detection devices, allowing the tool to serve itself in determining when to stop, thereby improving reliability without significantly increasing complexity.
Solution Approach 2:
The patent makes the existing motor and control system perform multiple functions: not only driving the impact mechanism but also serving as the detection system for fastening completion. The motor's current and commutation characteristics serve dual purposes of power delivery and fastening state indication, eliminating the need for separate detection mechanisms.
4Use of energy by moving object
If motor runs at full torque throughout fastening process, then energy efficiency is improved, but fastening precision deteriorates
Solution Approach 1:
The patent employs periodic impact action rather than continuous torque application. The impact mechanism delivers intermittent high-force pulses to the fastener, allowing the motor to operate in cyclic on/off states. This periodic action achieves precise fastening control while maintaining good energy efficiency, as the motor only consumes full power during impact phases rather than continuous torque delivery.
Solution Approach 2:
The patent dynamically adjusts motor torque output based on real-time detection of fastening state. The controller modulates motor power delivery from full torque during initial fastening to reduced or zero torque when fastening completion is detected, creating a dynamic control profile that optimizes both energy efficiency and fastening precision throughout the process.
Data Source
AI summary
An impact tool includes: an impact mechanism for applying an impact force to an output shaft; and a controller configured to control a motor. The controller is configured to: after the impact mechanism applies the impact force to the output shaft, determine, according to a load parameter of the output shaft in one or more impact cycles, that a fastener is in a fastening state and control the motor to enter a shutdown state. The load parameter of the output shaft includes the number of commutation cycles of the motor and/or a change in the number of commutation cycles of the motor.