Vehicle Seat Longitudinal Adjuster Play-Free Locking
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Solution Overview
Problem
Existing longitudinal adjusters for vehicle seats lack a mechanism that allows for secure locking without play in all positions, requiring deformation paths for locking elements and resulting in complex actuation and potential unintended seat movement.
Innovation Solution
A longitudinal adjuster with a locking unit featuring ratchet teeth of varying widths, where a wide ratchet tooth provides a play-free connection for power transmission, and conical recesses ensure secure locking, allowing for easy actuation and preventing unwanted seat displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking elements are designed to engage with multiple locking positions, then the locking reliability is improved, but the actuation complexity increases due to required deformation paths
Solution Approach 1:
The locking mechanism is segmented into multiple independent locking elements (first locking element and second locking element) that can engage with different locking positions independently. Each locking element has its own engagement path and locking position, allowing the system to achieve reliable multi-position locking without requiring complex deformation paths for a single locking element.
Solution Approach 2:
Instead of requiring a single locking element to deform and traverse multiple locking positions sequentially, the invention inverts the approach by having multiple locking elements engage different positions simultaneously or independently. The actuating force is distributed across multiple locking elements rather than concentrated on one element that must deform through multiple engagement points.
2Reliability
If multiple locking elements are used to ensure secure locking, then the locking reliability is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is divided into multiple independent locking elements (first locking element with first locking tooth, second locking element with second locking tooth) that can engage with different locking positions on the rail. Each locking element operates independently but contributes to the overall locking security, allowing reliable multi-position locking without requiring complex interactions between locking elements.
Solution Approach 2:
The invention uses multiple locking elements engaging at different positions along the rail, where each locking element provides partial locking action. The cumulative effect of multiple partial locking actions achieves secure overall locking without requiring each individual locking element to perform excessive or complex functions.
3Adaptability or versatility
If locking elements engage at different positions, then adaptability to various seat positions is improved, but the structural complexity increases
Solution Approach 1:
The locking system is segmented into multiple locking elements positioned at different locations along the rail, with each element capable of engaging at its specific locking position. This segmentation allows the seat to be locked at multiple different positions (adaptability) while each locking element maintains a relatively simple individual structure, avoiding the need for a single complex locking mechanism that would need to accommodate all positions.
Solution Approach 2:
Multiple locking elements are designed with similar structures that can each perform the same basic locking function at their respective positions along the rail. This universality allows the system to achieve multi-position adaptability without requiring each locking element to have complex position-specific features, as each element is a simplified universal component that locks at its designated position.
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~5
AI summary
The invention relates to a longitudinal adjuster (3) for a vehicle seat (1), comprising at least one lower rail (9), at least one upper rail (11), which can be moved in relation to the lower rail (9) in the longitudinal direction (x), and at least one locking unit (13) for locking the upper rail (11) in relation to the lower rail (9). According to the invention, the locking unit (13) comprises at least two locking elements (VR), which, in order to lock the upper rail (11) and the lower rail (9), engage in the upper rail and the lower rail in a blocking manner in steps in such a way that at least one of the locking elements (VR) pre-locks the upper rail (11) and the lower rail (9) with play in relation to each other in a pre-locking step and that at least one of the locking elements (VR) locks the upper rail (11) and the lower rail (9) to each other without play in a locking step. The invention further relates to a vehicle seat (1) comprising such a longitudinal adjuster (3).