Vehicle Seat-Track Assembly with Segmented Locking Pawls
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Solution Overview
Problem
Conventional seat-track assemblies in vehicles lack the ability to adjust seat positions in small increments and often experience rattling or 'chucking' due to relative movement between components, resulting in undesirable noise during use.
Innovation Solution
A seat-track assembly featuring a first and second track member with a locking mechanism that includes independently movable locking pawls, which engage and disengage with ramped and straight surfaces on the sidewalls to restrict or allow movement, providing precise adjustment and reducing noise through enhanced locking stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional locking mechanisms are used, then the seat assembly can be fixed at a position, but the seat cannot be adjusted in small increments and experiences rattling noise
Solution Approach 1:
The locking mechanism is segmented into multiple independent locking pawls (first locking pawl and second locking pawl) that can engage with different locking features simultaneously. This segmentation allows for more precise position control and reduces the play between components that causes rattling noise.
Solution Approach 2:
The locking features are designed with both ramped surfaces and straight surfaces, creating a two-dimensional engagement surface. The ramped surfaces provide for controlled engagement and disengagement, while the straight surfaces provide for precise positioning and elimination of lateral play, thereby reducing rattling noise.
2Reliability
If conventional locking mechanisms are used, then the seat assembly can be fixed, but the locking mechanism requires movement greater than 5mm to properly engage
Solution Approach 1:
The locking pawls are designed to be independently movable between locked and unlocked states, allowing dynamic adjustment without requiring excessive movement. The independent movability enables the seat to be adjusted and locked at any position within the travel range, improving ease of operation while maintaining reliable engagement.
Solution Approach 2:
The locking mechanism parameters have been optimized so that the locking features are distributed along the travel path at intervals that allow engagement with minimal movement. The ramped surface angles and pawl geometry are designed to achieve reliable engagement with less than 5mm of movement, improving both reliability and ease of operation.
3Stability of the object's composition
If conventional locking mechanisms are used, then the seat position can be fixed, but relative movement between components causes rattling noise
Solution Approach 1:
The first and second locking pawls work together in combination, with each pawl engaging different locking features. This merging of multiple locking actions creates a more stable connection between the track members, eliminating relative movement and the associated rattling noise while maintaining position stability.
Solution Approach 2:
The ramped surfaces act as intermediaries between the locking pawls and the straight surfaces. During engagement, the ramped surfaces guide the pawls into proper alignment and absorb minor misalignments, preventing impact noise while the straight surfaces maintain stable positioning without relative movement.
Data Source
AI summary
A vehicle seat-track assembly is provided and may include a first track member having a series of locking features and a second track member slidably supported by the first track member. The seat-track assembly may also include a locking mechanism having locking pawls movable between a locked state engaged with the locking features to restrict relative movement between the first and second track members and an unlocked state disengaged from the locking features to permit relative movement between the first and second track members. The locking pawls may each include locking elements that are received within respective ones of the series of locking features in the locked state such that the locking elements restrict relative movement between the first track member and the second track member in two directions when the locking pawls are in the locked state.