Transmission Gear Actuator Neutral Position Setting for Accurate Shifting
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Solution Overview
Problem
Existing automated manual transmissions face challenges in accurately setting neutral positions for gear-shifting due to cumulative tolerance and deviations in shift rail components, leading to shifting shocks, noise, and increased shifting time, especially with hall sensor-type shift motors that require frequent neutral position learning.
Innovation Solution
A method is introduced to determine a reference neutral position by reciprocating a shift finger in a free-range shift rail and then determining neutral positions for each speed-range shift rail by reciprocating a control finger, using angle sensors to measure rotation and rotational speed, and calculating average values to set precise neutral positions, reducing shifting errors and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reference neutral position is used for all speed-range shift rails, then the device complexity is reduced, but the manufacturing precision and shifting accuracy deteriorate due to cumulative tolerance
Solution Approach 1:
The patent divides the single reference neutral position into multiple speed-range-specific neutral positions (first through fourth speed-range neutral positions) corresponding to different shift rails. Each neutral position is determined independently by reciprocating the control finger in its respective speed-range shift rail, thereby eliminating cumulative tolerance effects and improving shifting accuracy for each gear range.
Solution Approach 2:
The patent applies different neutral position settings to different speed-range shift rails based on their specific requirements. Each shift rail (first, second, third, fourth) has its own optimized neutral position determined by local reciprocation testing, allowing each component to have the quality (neutral position accuracy) suited to its specific function rather than using a universal setting.
2Speed
If the sync start position is determined to be too close to the neutral position, then the shifting response is improved, but shifting shocks occur due to insufficient engagement distance
Solution Approach 1:
The patent employs a feedback mechanism where the control finger reciprocates in the speed-range shift rail and the system detects the current and rotational speed during this process. Based on this feedback information, the exact neutral position is determined, which in turn allows for precise determination of the sync start position. This ensures optimal distance between neutral and sync start positions, achieving fast response without shifting shocks.
Solution Approach 2:
The patent changes the parameter of neutral position setting from a fixed single position to multiple adjustable positions based on different speed ranges. This parameter change enables optimization of the distance between neutral position and sync start position for each gear range, allowing the sync start position to be positioned optimally - not too close to avoid shocks, not too far to maintain response speed.
3Measurement precision
If neutral position learning is performed frequently with hall sensor-type shift motors, then the shifting accuracy is maintained, but the loss of time increases
Solution Approach 1:
The patent implements a self-service neutral position determination method where the control finger automatically reciprocates in each speed-range shift rail and the system autonomously detects the neutral position based on current and rotational speed patterns. This self-determination mechanism reduces reliance on frequent hall sensor-based learning operations, thereby maintaining positioning accuracy while reducing the time loss associated with repeated learning cycles.
Data Source
AI summary
Provided is a method of setting a neutral position of each speed-range shift rail for accurate gear-shifting in a transmission gear actuator. The method includes a reference neutral position determination step of determining a reference neutral position as an absolutely neutral position by reciprocating a shift finger in a free-range shift rail, and a speed-range neutral position determination step of determining a neutral position of each speed-range shift rail by reciprocating a control finger in the speed-range shift rail. Since the neutral position of each speed-range shift rail is set through the above method, it is possible to perform more accurate gear-shifting and prevent incomplete gear engagement by performing the gear-shifting at the neutral position of each speed-range shift rail.