Impact Tool Motor Cycling for Low-Speed Screw Surface Protection
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Solution Overview
Problem
Existing impact tools, such as impact screwdrivers, often damage operation surfaces due to excessively high speeds when loosening or tightening thin screws, and require continuous operation to ensure complete flushness, leading to potential damage.
Innovation Solution
An impact tool with an electric motor, output shaft, impact mechanism, and controller that operates in low-speed mode by periodically shutting down and restarting the motor, adjusting the duty cycle based on load conditions, and controlling the impact frequency to prevent excessive speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impact tool operates at high speed to improve productivity, then the screwing efficiency is improved, but the operation surface will be damaged due to excessively high speed
Solution Approach 1:
The patent implements periodic shutdown of the electric motor during low-speed mode operation. The controller shuts down the motor after a preset number of impacts and restarts it after a preset period, creating a periodic on-off action pattern. This periodic operation allows the impact tool to maintain low impact frequency and prevent surface damage while still completing the screwing task, directly resolving the contradiction between productivity and surface protection.
2Manufacturing precision
If the impact tool operates continuously to ensure complete flushness of the screw, then the screwing completeness is improved, but the operation surface will be damaged by excessively fast impact
Solution Approach 1:
The patent implements dynamic switching between low-speed mode and normal mode based on real-time detection of screw flushness. When the screw is detected to be completely flush with the operation surface, the controller automatically switches from low-speed mode with periodic shutdown to normal mode with continuous operation. This dynamic adaptation allows the system to maintain manufacturing precision while avoiding surface damage during the critical flushing stage.
Solution Approach 2:
The patent employs feedback control through a detector that monitors whether the screw is completely flush with the operation surface. The detector's signal is fed back to the controller, which adjusts the motor operation mode accordingly. This feedback mechanism enables the system to maintain screw flushness while preventing excessive impact frequency that would damage the operation surface.
3Object-affected harmful factors
If the electric motor is shut down frequently to control impact frequency, then the impact frequency is reduced to prevent damage, but the energy consumption increases due to repeated startup
Solution Approach 1:
The patent implements periodic shutdown with optimized timing parameters. The controller shuts down the motor after a preset number of impacts (first preset value) and restarts after a preset period (second preset value). By optimizing these timing parameters, the system achieves sufficient surface protection while minimizing the number of shutdown-restart cycles, thereby reducing energy consumption from repeated motor startup.
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
The impact tool effectively prevents damage to operation surfaces by controlling the impact frequency and speed, ensuring stable operation at both low and high speeds, and improving user experience.
Implementation Method 1
an electric motor including a drive shaft rotating about a first axis
Implementation Method 2
an impact mechanism for applying an impact force to the output shaft, where the impact mechanism includes an impact block driven by the drive shaft and a hammer anvil receiving an impact from the impact block
Data Source
AI summary
An impact tool includes: an impact mechanism, where the impact mechanism includes an impact block driven by a drive shaft and a hammer anvil receiving an impact from the impact block, and the hammer anvil is connected to an output shaft; and a controller configured to control an electric motor. The controller is configured to, when the impact tool is in a low-speed mode and it is detected that the impact mechanism applies an impact force to the output shaft, perform the operations periodically: determining that the impact mechanism impacts a preset number of times and controlling the electric motor to shut down for a preset period and then restart.