Seat-Track Assembly Locking Pawl Segmentation
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Solution Overview
Problem
Conventional seat-track assemblies in vehicles do not allow for precise adjustment of seat position in small increments and often experience rattling or 'chucking' due to relative movement between components, leading to undesirable noise during use.
Innovation Solution
A seat-track assembly with a locking mechanism featuring four independently movable locking pawls and a series of locking features, allowing for precise adjustment in 5 mm increments and reducing rattling by ensuring only two pawls engage the locking features at a time, thereby minimizing movement between components.
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 user cannot adjust the seat position in small increments and must move it greater than 5mm for the locking mechanism to engage
Solution Approach 1:
The locking mechanism is divided into four independently movable locking pawls instead of a single locking component. Each pawl can engage with locking features independently, allowing the seat to be secured at multiple discrete positions along the track. This segmentation enables precise positioning in small increments while maintaining ease of operation through the same actuating lever.
2Reliability
If conventional locking mechanisms are used, then the seat position can be fixed, but rattling or chucking occurs during use due to relative movement between components
Solution Approach 1:
Four locking pawls are combined to work simultaneously on the same seat track, with each pawl engaging locking features at different positions. This creates multiple contact points between the locking mechanism and track, eliminating relative movement between components and preventing rattling or chucking noises during vehicle operation.
Solution Approach 2:
Each locking pawl is designed with specific geometric features that match corresponding locking features on the track. The pawls have varying engagement depths and contact areas, creating optimal local contact conditions at each locking position to maximize stability and minimize vibration-induced noise.
3Measurement precision
If four independently movable locking pawls are used, then precise adjustment in 5mm increments is enabled and rattling is reduced, but the device complexity increases
Solution Approach 1:
The four locking pawls are designed as identical or near-identical components that perform the same function of engaging with locking features on the track. This universality simplifies manufacturing and assembly despite the increased number of components, as each pawl can be produced using the same process and interchanged in any position.
Solution Approach 2:
The locking pawls are independently movable and automatically engage with the locking features on the track through spring biasing or gravitational force. When the actuating lever is released, the pawls self-adjust to their locked positions without requiring additional actuators or complex control mechanisms, reducing the overall system complexity.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A seat-track assembly (10; 110) is provided and may include a first track member (18; 118) having a series of locking features (32; 132) and a second track member (20; 120) slidably supported by the first track member. The seat-track assembly may also include a locking mechanism (22; 122) having at least two locking pawls (46; 146) 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 at least two locking pawls may each include at least two locking elements (54; 154) that are received within respective ones of the series of locking features in the locked state such that each of the locking elements simultaneously 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.