Motorized Shift Mechanism With Backlash Angle Correction
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Solution Overview
Problem
Existing shift devices require excessive load on the detent spring to correct the target rotation position due to increased backlash caused by wear, leading to inaccurate position control during shift switching operations.
Innovation Solution
A shift device with a detent plate having valley portions and a detent spring, where a motor and sensors detect rotation angles to correct deviations from a preset backlash, allowing the detent spring to reach valley bottoms without excessive load, using a driving force transmission mechanism with a speed reducing mechanism to maintain accurate position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detent spring is pressed against the P wall or non-P wall for a predetermined time to obtain wall positions, then the target rotation position can be corrected, but excessive load is applied to the detent spring
Solution Approach 1:
The patent replaces the mechanical method of pressing the detent spring against walls with a sensor-based detection system. The P wall position sensor and non-P wall position sensor detect wall positions non-contactly, eliminating the need to apply excessive load to the detent spring while maintaining measurement precision for correction control.
Solution Approach 2:
The patent introduces sensors as intermediary devices between the control system and the wall positions. Instead of directly pressing the detent spring against walls, the sensors act as mediators to detect wall positions and provide feedback to the correction control, enabling position correction without excessive spring load.
2Measurement precision
If the P-ECU performs P wall position detection and non-P wall position detection to correct target rotation position, then position accuracy can be maintained, but the control system becomes more complex
Solution Approach 1:
The patent implements feedback control where the P wall position sensor and non-P wall position sensor continuously provide position information to the correction control. The correction control uses this feedback to dynamically adjust the target rotation position, maintaining accuracy while automating the correction process to manage system complexity.
Solution Approach 2:
The correction control pre-calculates and stores the relationship between wall positions and target rotation positions based on sensor data. This preliminary action enables the system to quickly determine corrected positions without complex real-time calculations during operation, simplifying the control logic while maintaining precision.
Data Source
AI summary
A shift device includes: a shift switching member including valley portions provided so as to correspond to shift positions; a positioning member causing the shift position to be established while being fitted in any of the valley portions of the shift switching member; a motor driving the shift switching member and including a rotor and a stator; a driving force transmission mechanism transmitting a driving force from the motor to the shift switching member; and a rotor rotation angle sensor and an output shaft rotation angle sensor detecting rotation angles of the rotor and the shift switching member. The shift device corrects a deviation from a center of a preset backlash when a backlash width included in the driving force transmission mechanism detected based on output values of the output shaft rotation angle sensor and the rotor rotation angle sensor is a value or more during a shift switching operation.