Shift Lever Assembly Tactile Feedback Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In shift-by-wire vehicle transmission systems, there is a lack of clear tactile feedback during gear changes, which can lead to confusion for drivers accustomed to mechanical shifters, and the return stroke often provides unintended feedback, complicating the shifting process.
Innovation Solution
A shift lever assembly with a tactile feedback device that engages feedback features during the control movement but decouples from them during the return movement, using a ball and selector path design to provide distinct feedback during gear changes and minimize feedback during the return to the home position, ensuring a smooth and intuitive shifting experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If feedback features are provided along the entire shift lever path, then tactile feedback during gear changes is improved, but unintended feedback during return stroke occurs
Solution Approach 1:
The feedback path is segmented into distinct sections: a selector path with feedback features for gear changes, and a separate return path without feedback features. The coupler selectively engages the selector path during control movements and the return path during return movements, providing tactile feedback only when needed for gear selection.
Solution Approach 2:
Different portions of the shift mechanism have different tactile properties. The selector path contains feedback features (protrusions, ridges, or textured surfaces) that provide tactile feedback, while the return path is designed to be smooth and feedback-free, creating localized quality differences that guide driver interaction.
2Loss of information
If a mechanical cable couples the shift lever to the transmission, then direct tactile feedback is provided, but the system complexity increases and shift-by-wire functionality is lost
Solution Approach 1:
The coupler acts as an intermediary mechanism that translates the driver's shift lever movements into transmission shift commands. During the control stroke, the coupler engages feedback features to provide tactile feedback to the driver, while during the return stroke, it disengages to prevent unintended feedback, effectively mediating between the shift lever and transmission.
Solution Approach 2:
The patent replaces the traditional continuous mechanical cable connection with a more complex but controllable mechanism involving a coupler that can selectively engage and disengage from feedback features. This substitution allows for electronic control of the shifting process while maintaining tactile feedback when needed.
3Productivity
If the shift lever returns automatically to home position, then the shifting process is streamlined, but unintended tactile feedback may confuse the driver
Solution Approach 1:
The coupler dynamically changes its engagement state based on the direction of movement. During the control stroke (gear selection), the coupler engages with feedback features to provide tactile information. During the return stroke (automatic return to home), the coupler disengages from feedback features, creating a dynamic system that adapts its feedback characteristics to the operational phase.
Solution Approach 2:
The shifting process involves periodic cycles of control stroke and return stroke. During each control stroke, feedback features are engaged to provide tactile information for gear selection. During each return stroke, feedback features are disengaged to prevent unintended feedback. This periodic engagement and disengagement aligns with the cyclic nature of the shifting operation.
Data Source
AI summary
A shift lever assembly may be used to shift among gears of a vehicle transmission. The shift lever assembly may be of a so-called shift-by-wire type where a shift lever is not directly mechanically coupled to the transmission but is electrically communicated with the transmission to effect transmission gear changes. A driver may move the shift lever through a shift stroke to cause a transmission gear change, and, for example, when the driver releases the shift lever, an actuator may automatically return the shift lever to a home position during a return stroke. The shift lever assembly may include feedback features that provide feedback to the driver that the shift lever is moving among various positions during the shift stroke, and the assembly may be configured so that the shift lever returns to the home position with less or no feedback features being encountered during the return stroke.