Electric Tool Gear Shifting Control for Incomplete Engagement
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Solution Overview
Problem
Conventional electric tools face difficulties in quickly and smoothly modifying the reduction ratio due to incomplete gear shifts, leading to shock and potential breakdowns, as the timing of switching member engagement with gear members is inconsistent with motor rotation control.
Innovation Solution
An electric tool with a reduction mechanical unit that includes a gear shift actuator, slide position detecting unit, and control unit, which modifies the motor's rotational power and relative rotation speed to ensure smooth gear shifting by detecting the slide position of the switching member and adjusting its movement to prevent incomplete gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the motor is stopped or rotation is reduced to suppress shock during gear engagement, then shock is suppressed, but the time required to complete reduction ratio modification increases
Solution Approach 1:
The control unit starts the solenoid in advance before the switching member actually engages with the gear member, based on predicted timing calculated from the difference between actual and target rotation positions. This preliminary action allows the solenoid to be ready to engage the switching member smoothly without waiting for the motor to stop, thereby reducing the time for reduction ratio modification while still suppressing shock through controlled engagement
2Reliability
If the switching member is engaged with the gear member at incorrect timing, then incomplete gear shift state occurs, but the mechanism complexity increases to detect and correct this state
Solution Approach 1:
The control unit continuously monitors the rotation position of the switching member and compares it with the target position. When an incomplete gear shift state is detected (i.e., the switching member has not reached the target position within the expected time), the control unit provides feedback and adjusts the motor rotation speed or solenoid operation to correct the engagement timing, ensuring reliable gear shift completion
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 solution enables quick resolution of incomplete gear shifts, reducing shock and overload, and allows for efficient and stable automatic gear shifting, enhancing the tool's ability to modify the reduction ratio swiftly and smoothly.
Implementation Method 1
these conventional electric tools stop or reduce rotation of a motor... when the solenoid is started
Data Source
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AI summary
In an electric tool according to the present invention, a reduction mechanical unit is formed so as to switch the reduction ratio by using a switching member moving slidably in an axial direction, and a gear member engaging with the switching member. A reduction ratio switching means includes: a gear shift actuator sliding the switching member; a drive state detecting unit detecting a driving state of a motor; a slide position detecting unit detecting a slide position of the switching member; and a control unit starting the gear shift actuator and temporarily modifying a rotational power of the motor. The control unit modifies a relative rotation speed between the switching member and the gear member when a gear shift is in an incomplete state in which the switching member has not moved slidably to a target position yet.