Shift Control Device for Accurate Gear Engagement
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Solution Overview
Problem
Existing shift control devices face inaccuracies in gear change operations due to design or assembly errors, which cause variations in mechanical maximum rotation angles, leading to miscalculated neutral positions and unreliable gear changes.
Innovation Solution
A shift control device with a stopper mechanism to regulate the shift shaft's rotation and a determination device to ensure the shift shaft does not exceed the mechanical maximum rotation angle, allowing for accurate clutch disengagement and engagement processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the neutral position is calculated based on detected rotation angles assuming symmetric maximum rotation angles, then the calculation is simple, but the gear change accuracy deteriorates due to manufacturing variations
Solution Approach 1:
The system uses a sensor to detect the actual maximum rotation angles in both rotation directions and feeds this information back to the control unit. The control unit then calculates the neutral position based on these detected values rather than assuming symmetry, thereby compensating for manufacturing variations and ensuring accurate gear changes.
Solution Approach 2:
The invention changes the parameter used for neutral position calculation from a fixed theoretical value to a dynamically detected actual value. By measuring the real maximum rotation angles during operation and using these measured parameters for calculation, the system adapts to individual vehicle variations and maintains precision despite manufacturing tolerances.
2Speed
If the shift shaft rotation is not strictly controlled within mechanical limits, then the operation speed is faster, but the reliability of gear change deteriorates
Solution Approach 1:
The control unit performs preliminary determination of whether the shift shaft has reached the maximum rotation angle before initiating clutch engagement. This preliminary check ensures that the shift shaft is definitely within the mechanical limit range before proceeding with the next operation, preventing unreliable gear changes while maintaining efficient operation timing.
Data Source
AI summary
A shift control device in which a number of times that an angle change amount per a defined time period is successively equal to or less than a determined value is calculated, when a rotation angle of a shift shaft is equal to or more than a threshold value. In addition, an abutting state determination is performed that determines whether the number of times is equal to or above a threshold value, and if it is determined that there is an abutting state (namely, the shift shaft has reached an actual mechanical maximum rotation angle), processing shifts to an engagement process of a shift clutch.