Electric Tool Motor Speed Control for Reduced Vibration
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Solution Overview
Problem
The efficiency of work is reduced in electric tools like hammers and hammer drills due to slow idling control, which causes a time lag when frequently switching between on and off states, leading to increased noise and vibration.
Innovation Solution
An electric tool with a control unit that drives the motor at a first rotation speed in a non-operating state and switches to a higher second rotation speed when the tool is in an operating state, and maintains the higher speed under specific conditions after the operation is released, even if the tool is in a non-operating state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If slow idling control is implemented to reduce noise and vibration in unloaded state, then noise and vibration are reduced, but work efficiency decreases due to time lag when frequently switching between on and off states
Solution Approach 1:
The patent applies dynamics by making the motor rotation speed adjustable based on operational state. The control unit dynamically switches between first rotation speed (lower) in non-operating state and second rotation speed (higher) in operating state, optimizing both noise reduction and work efficiency through adaptive speed control
Solution Approach 2:
The patent changes the rotation speed parameter of the motor based on detected operational conditions. When the tip tool is in non-operating state, the motor runs at first rotation speed; when in operating state, it switches to second rotation speed, thereby reducing noise during idle while maintaining high efficiency during actual work
2Object-affected harmful factors
If the motor is driven at low rotation speed in non-operating state, then noise and vibration are reduced, but the time lag increases when resuming operation
Solution Approach 1:
The control unit maintains the motor in a ready state by detecting when the tip tool is in operating state and pre-maintaining higher rotation speed, so that when the operation unit is activated again, the motor can immediately deliver full power without time lag, while still reducing noise when truly idle
3Productivity
If the motor switches to high rotation speed immediately when operation unit is activated, then work efficiency is improved, but noise and vibration increase in unloaded state
Solution Approach 1:
The system dynamically adjusts motor rotation speed based on the actual operational state of the tip tool. The control unit monitors whether the tip tool is in operating or non-operating state and accordingly sets the motor to first or second rotation speed, achieving optimal balance between noise reduction and work efficiency
Solution Approach 2:
The control unit uses feedback from the detection unit about the tip tool's operational state to adjust motor rotation speed. When the tip tool is detected to be in non-operating state, the motor is controlled at lower speed; when in operating state, it switches to higher speed, creating a closed-loop control system that optimizes both noise and efficiency
Data Source
AI summary
Provided is an electric tool with which work efficiency can be improved. A controller of an electric tool can execute: a first control, whereby during a non-operating state after a motor has started up and before a tip tool is set to be in an operating state, the motor is driven at a slow idling rotation speed, and when the tip tool is set to be in the operating state, the motor is driven at a normal rotation speed which is higher than the slow idling rotation speed; and a second control, whereby in a case where a trigger switch has been turned off in a state where the motor is being driven at the normal rotation speed and the trigger switch is thereafter turned on again under a prescribed condition, the motor is driven at the normal rotation speed regardless of the state of the tip tool.