Manual Transmission Shifter Guide Device for Lash Reduction
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Solution Overview
Problem
Conventional manual transmission shifters experience lateral lash or free play, which is undesirable and not effectively addressed by existing technologies.
Innovation Solution
A shifter assembly with a shift lever guide device and transmission gate guide that include longitudinally extending channels and slots, respectively, to define a shift pattern, reducing lateral free play while allowing longitudinal motion, and featuring a guide plate within the shifter housing to control the shift lever's movement and reduce lash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shift lever is allowed to move freely in lateral direction, then the ease of operation is improved, but lateral lash or free play occurs which degrades the quality of operation
Solution Approach 1:
The guide device segments the continuous lateral movement space into discrete channels, each corresponding to a specific gear position. The shift lever is constrained to move only within these predefined channels, eliminating free play while maintaining operational ease through intuitive channel alignment.
Solution Approach 2:
The guide device acts as an intermediary between the shift lever and the transmission gate guide. It translates the driver's lateral shift lever movement into precise longitudinal motion of the shift finger, mediating the control action to eliminate lateral lash while preserving ease of operation.
2Object-generated harmful factors
If the channel width is made tight to reduce lateral free play, then the lateral lash is reduced, but the difficulty of operation increases due to restricted movement
Solution Approach 1:
The guide device provides different levels of constraint in different directions: tight lateral constraints within channels to eliminate lash, but loose longitudinal constraints between channels to allow easy shifting. This local differentiation of constraint quality resolves the contradiction between reducing lateral free play and maintaining ease of operation.
3Device complexity
If the shift lever and shift finger enter the channels and slots at the same time, then the coordination is simplified, but interference between components occurs during gear engagement
Solution Approach 1:
The guide device is designed so that the shift lever enters its channel before the shift finger enters its corresponding slot. This preliminary positioning of the shift lever prepares the transmission for upcoming gear engagement, allowing the shift finger to follow smoothly without interference while maintaining simple coordination geometry.
Data Source
AI summary
A system for lash reduction of a shifter for a manual transmission includes a shifter assembly having a housing, a shift lever and a shift lever guide device positioned in the housing. The guide device includes a plurality of shift channels connected by a select channel and defines a shift pattern for the shift lever. The transmission gate guide includes a corresponding plurality of shift finger slots connected by a select slot and defines a pattern for a shift finger of the transmission. Movement of the shift lever into one of the channels operatively moves the shift finger into a corresponding one of the slots. Each of the channels includes a channel width complimentary to a width of the shift lever so as to substantially reduce lateral free play of the shift lever when received in the channels while allowing longitudinal motion of the shift lever in the channels.