Transmission Shifter Feel Positioner for Lash and Noise Reduction
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Solution Overview
Problem
Traditional vehicle transmission shifters face challenges in reducing noise and lash between gear positions due to conflicting requirements for smooth shifting and noise reduction, with increased lash often leading to undesired noise and wear over time.
Innovation Solution
A feel positioner mechanism with first and second undulations defining a common center point and opposing slopes, along with biased detents that engage these undulations to combine centering forces, eliminating lash and noise by precisely locating the selector in gear positions without a lash-permitting zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional forces are applied to the feel positioner mechanism to reduce noise, then noise level decreases, but shifter movement smoothness deteriorates and excessive clicking noise occurs
Solution Approach 1:
The feel positioner mechanism is segmented into two separate detents (first and second detents) that independently engage with corresponding undulations. Each detent handles noise reduction from a different direction, allowing the mechanism to reduce noise without compromising smooth movement through any single detent's excessive force application.
Solution Approach 2:
The first and second detents act as counterbalancing elements that apply forces in opposite directions (first direction and second direction respectively). These counteracting forces eliminate lash while distributing the noise-reduction function across two elements, preventing any single element from creating excessive clicking noise.
2Manufacturing precision
If the detent engages deeply in the undulation depression to reduce lash, then positional precision improves, but noise increases due to snapping/clicking
Solution Approach 1:
The positioning function is segmented between two detents that each engage with undulations from different directions. This segmentation allows the mechanism to achieve precise positioning through combined action while each individual detent operates with reduced engagement depth, minimizing snapping noise.
Solution Approach 2:
The first and second undulations are positioned asymmetrically relative to the selector's center line, with each undulation's depression oriented to receive its corresponding detent from a different direction. This asymmetric arrangement enables precise positioning through vector combination while reducing the depth of engagement required from each individual detent.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces noise and lash in vehicle transmission shifters, providing a flexible design with few parts and low assembly costs, while maintaining smooth shifting and precise gear engagement.
Implementation Method 1
The first detent is biased against the first undulation to engage the associated slope and bias the selector toward the common center point from a first direction with a first centering force, and the second detent is biased against the second undulation to engage the associated slope and bias the selector toward the common center point from a second direction with a second centering force
Data Source
AI summary
A selector apparatus comprises a shift lever operably supported on a base for movement between gear positions, and a feel positioner mechanism with offset detent members, where a first detent engages first undulations for biasing the shift lever toward a center of a selected gear position from a first direction, and a second detent engages second undulations for biasing the selector lever toward the center of the selected gear position from a different second direction to the common center point. By the arrangement, the first and second undulations define opposing angled slopes toward the common center point. This allows the undulations to be designed to provide any desired level of biasing force toward the center point without the limitations of a single undulation defining the center point.