Impact Tool Motor Control via Current-Based Impact Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing impact tools require skilled user operation to adjust motor revolutions efficiently, leading to inefficiencies, especially for unskilled users, as the number of revolutions is controlled solely by user manipulation of the trigger switch.
Innovation Solution
An impact tool with a control unit that performs vector control on the motor, including an impact detection unit to determine if an impact operation is being performed, limits the increase in motor revolutions before impact and removes this limit once impact is detected, allowing for efficient torque application and reducing the risk of screw tilting or disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of revolutions is controlled solely by user manipulation of the trigger switch, then the device structure remains simple, but unskilled users cannot achieve efficient work
Solution Approach 1:
The impact tool automatically detects impact operations through current monitoring and self-adjusts the motor revolutions without user intervention. The control unit detects impact based on excitation current or torque current patterns and autonomously removes revolution limits, enabling the tool to serve itself and eliminate the need for skilled user judgment.
Solution Approach 2:
The system continuously monitors the motor current (excitation current or torque current) to detect when an impact operation is occurring. This feedback loop allows the control unit to recognize impact conditions and automatically adjust the revolution limit accordingly, creating a closed-loop control system that responds to actual operating conditions.
2Productivity
If the motor revolutions are increased during impact operation, then the fastening speed improves, but the risk of screw tilting or disengagement increases
Solution Approach 1:
The revolution limit is made dynamic rather than fixed. The control unit adjusts the revolution limit based on the detected operation phase: maintaining a limited state during non-impact phases for stability, and transitioning to an unlimited state during impact phases for maximum fastening speed. This dynamic adaptation allows the system to optimize both reliability and productivity at different moments.
Solution Approach 2:
The system places a limit on motor revolutions in advance before impact detection to prevent screw tilting or disengagement. Once impact is detected through current monitoring, the limit is removed to enable high-speed fastening. This preliminary protective action ensures screw stability is maintained during the critical initial phase before impact begins.
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 work efficiency by allowing the impact tool to automatically adjust motor revolutions based on impact detection, improving user performance regardless of skill level and reducing the risk of screw tilting or disengagement during fastening operations.
Implementation Method 1
an impact tool including a motor 15, a control unit 4, an output shaft 21, a transmission mechanism 18
Implementation Method 2
The impact mechanism 17 performs an impact operation according to the magnitude of torque applied to the output shaft 21. The impact mechanism 17 applies impacting force to the output shaft 21
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An object of the present disclosure is to provide an impact tool, a method for controlling the impact tool, and a program, all of which contribute to improving work efficiency. An impact tool (1) includes a motor (15), a control unit (4), an output shaft, a transmission mechanism, and an impact detection unit (49). The transmission mechanism includes an impact mechanism. The impact mechanism applies impacting force to the output shaft while performing an impact operation. The impact detection unit (49) determines, based on at least one of an excitation current (current measured value id1) to be supplied to the motor (15) or a torque current (current measured value iq1) to be supplied to the motor (15), whether or not the impact operation is being performed. The control unit (4) places a limit on an increase in the number of revolutions of the motor (15) before the impact detection unit (49) detects the impact operation and removes the limit on the increase in the number of revolutions of the motor (15) when the impact detection unit (49) detects the impact operation.