Motorized Shift Mechanism Backlash Centering for Faster Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shift devices require a lengthy process to accurately determine the rotational angle of the motor corresponding to each valley bottom of the detent plate, which increases tact time and can lead to reduced durability due to detent spring collisions with wall portions.
Innovation Solution
A shift device that detects the width of backlash in the speed reduction mechanism using output values from both the rotor and output shaft rotational angle sensors while the positioning member continuously passes through valley parts, allowing for the calculation of the rotational angle corresponding to the center of the backlash, thereby simplifying the operation and reducing tact time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor is rotated multiple times in forward and reverse directions to detect backlash width for each valley part, then the positioning accuracy of the detent spring is improved, but the tact time is increased
Solution Approach 1:
The patent combines the backlash detection process into a single continuous operation that spans multiple valley parts, rather than performing separate detection for each valley part. This merging of operations reduces the total time required while maintaining positioning accuracy through the use of both rotational angle sensors to calculate backlash width.
Solution Approach 2:
The patent makes the backlash width value universal across all valley parts by detecting it once during a continuous operation and applying this single detected value to calculate the rotational angle corresponding to the center of backlash for each valley part, rather than performing separate detection for each valley part.
2Speed
If the detent spring is allowed to fall freely into the valley part, then the operation speed is improved, but the durability is reduced due to collisions with wall portions
Solution Approach 1:
The patent performs preliminary detection of the backlash width and calculation of the rotational angle corresponding to the center of the backlash before the detent spring falls into the valley part. This allows the system to control the motor to stop at the precise position where the detent spring centers in the valley part, preventing collisions with wall portions while maintaining operation speed.
Solution Approach 2:
The patent uses feedback from both the rotational angle sensor and the output shaft rotational angle sensor to detect the backlash width and determine the precise stopping position. This feedback mechanism ensures the motor stops at the correct position corresponding to the center of the backlash, preventing the detent spring from colliding with wall portions during operation.
Data Source
AI summary
A shift device includes: a shift switching member including valley parts corresponding to a shift position; a positioning member provided to establish the shift position in a state of being fitted into any one of the valley parts; a motor including a rotor and a stator and driving the shift switching member; a speed reduction mechanism section rotating the shift switching member in a state in which a rotation speed transmitted from the motor is reduced; a rotor rotational angle sensor detecting a rotational angle of the rotor; and an output shaft rotational angle sensor detecting a rotational angle of the shift switching member A width of a backlash included in the speed reduction mechanism section is detected, and the rotational angle of the motor corresponding to the center of the backlash is acquired.