Shifter Assembly Bushing Sandwich Design for Lash Reduction
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Solution Overview
Problem
Existing shifter assemblies experience lash and inefficiencies in defining gear selection ranges due to the space between bushings and channels, leading to suboptimal movement restrictions.
Innovation Solution
A shifter assembly design featuring a lever with angular ramps and bushings that are sandwiched between engagement surfaces, allowing for reduced lash and precise movement definition through rotatable pins and deformation of bushings to prevent plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bushings are disposed within a channel with space between them, then the shifter assembly allows for movement range, but lash is created between the bushings and channel
Solution Approach 1:
The bushings are changed from a fixed dimensional component to a deformable component that can elastically compress. This parameter change allows the bushings to adapt their size to eliminate lash while maintaining movement range, resolving the contradiction between operational freedom and precision.
Solution Approach 2:
The engagement surfaces are designed to compress the bushings beforehand during assembly or initial operation, eliminating gaps and lash before normal operation begins. This pre-compression ensures tight coupling between the shifter components while preserving the necessary movement range.
2Ease of operation
If the lever and handle are loosely coupled, then ease of movement is improved, but precision of gear selection is reduced
Solution Approach 1:
The coupling between lever and handle is changed from a rigid fixed connection to an elastically deformable connection. The bushings can compress to provide precise positioning when needed while allowing movement during operation, resolving the contradiction between ease of movement and selection precision.
3Measurement precision
If the bushings are made more rigid to reduce deformation, then precision is maintained, but resistance to excessive force increases causing potential damage
Solution Approach 1:
The bushing material properties are optimized to provide elastic deformation within a controlled range. This allows the bushings to maintain precision through elastic recovery while absorbing excessive forces through controlled deformation, preventing damage to other components.
Solution Approach 2:
The bushings are pre-compressed to a level that maintains precision positioning while creating a cushioning effect. This pre-compression allows the bushings to absorb subsequent excessive forces through additional compression, protecting the rigid components from damage while maintaining positioning accuracy.
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 design effectively reduces lash and enhances the precision of gear selection ranges, ensuring reliable and long-lasting operation by preventing excessive deformation of bushings.
Implementation Method 1
The first bushing is sandwiched between the pair of first engagement surfaces and the second bushing is sandwiched between the pair of second engagement surfaces to define a second range of movement and to fully couple the lever to the one of the handle and the support
Data Source
AI summary
The subject invention provides for a shifter assembly for selecting one of a plurality of gears of a transmission of a vehicle. The shifter assembly includes a pin engaging a lever and one of a handle and a support and rotatable towards first and second ramps to define a first range of movement between the lever and one of the handle and the support. A first post and a second post extend from the lever. A first bushing is attached to the first post and a second bushing is attached to the second post. A pair of first and second engagement surfaces are disposed on the one of the handle and the support. The first bushing is sandwiched between the pair of first engagement surfaces and the second bushing is sandwiched between the pair of second engagement surfaces to define a second range of movement.