Manual Transmission Interlock Error Compensation
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Solution Overview
Problem
In transmissions with active interlock shifting mechanisms, undetected errors or damages in the shifting mechanism can lead to unsafe shifting positions, potentially causing damage or unsafe driving conditions, as the control system may not recognize these issues in time.
Innovation Solution
A method that brings the selector fork into a safe shifting position, such as neutral, using a combination of shifting finger and layout geometry mechanisms, before shifting into the target gear, to ensure the transmission remains in a safe state, even if an error has not been detected, and activates error handling once the error is recognized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shifting mechanism operates without additional safety checks, then the shifting speed and productivity are maintained, but the reliability and safety deteriorate when undetected errors occur
Solution Approach 1:
The patent applies preliminary action by bringing the selector fork into a safe shifting position (neutral) before completing the gear shift operation. This preventive measure ensures that even if an error occurs during the shifting process, the transmission will end up in a safe state. The method performs this safety action in advance, particularly for non-time-critical shifting processes, to guarantee reliability without compromising normal shifting speed when errors are not present.
2Reliability
If the control system continuously monitors for errors, then the reliability improves, but the device complexity and measurement precision requirements increase
Solution Approach 1:
The patent applies self-service by utilizing the existing shifting mechanism components (shifting finger, layout geometry, selector fork) to perform safety functions without adding separate monitoring systems. The control system leverages the natural movement and positioning of these components during the shifting process to detect errors and ensure safe operation, thereby improving reliability while avoiding increased device complexity.
3Object-affected harmful factors
If the shifting process follows the traditional sequence without intermediate safety positions, then the productivity is maintained, but the harmful factors increase due to potential unsafe shifting positions
Solution Approach 1:
The patent introduces an intermediary safe position (neutral) into the shifting sequence. The selector fork is first brought into this intermediate safe position before proceeding to the target gear position. This intermediary step eliminates harmful unsafe shifting positions by ensuring the fork is in a known safe state, while the overall productivity is maintained by only applying this intermediate step when necessary (for non-time-critical shifts or when errors are detected).
Data Source
AI summary
A method for controlling a gear-shifting process from an initial gear to a target gear in a manual transmission with active interlock. According to the method, the active interlock gear-shifting mechanism includes at least one shifting finger which co-operates with a selector fork, and has a layout geometry including a finger and a cam. The method contains the following steps: the selector fork of the initial gear is brought into a reliable shifting position by a method for compensating errors on the gear shifting mechanism, and/or the selector fork of the target gear is brought into a reliable shifting position a method for compensating errors on the gear shifting mechanism, before the target gear is engaged, when ever a temporarily non-critical gear-shift is to be carried out.