Vehicle Seat Rail End Stop Design for Displacement Limiting
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Solution Overview
Problem
Existing longitudinal adjusters for vehicle seats lack an optimized arrangement of end stops to effectively limit relative displacement without compromising the rigidity or strength of the seat rails, and they often fail to prevent undesirable distortion under load.
Innovation Solution
A longitudinal adjuster design featuring a lower C-shaped seat rail with downwardly bent portions and an upper U-shaped seat rail, where the end stop is configured as a partial extension of the lower rail's bent portions, including an elongate hole to absorb bending forces and prevent upward bending, and a stop element on the upper rail that can be arranged to maintain centering and prevent vertical sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end stops are added to limit relative displacement, then displacement limitation is improved, but structural strength and rigidity deteriorate due to additional cut-outs and free-cuts
Solution Approach 1:
The end stop is segmented into two functional parts: a first end stop portion that limits displacement and a second end stop portion that reinforces structural strength. This segmentation allows the displacement limitation function to be separated from the strength-critical regions, avoiding cut-outs in high-stress areas while maintaining both functions.
Solution Approach 2:
The end stop is positioned specifically in regions where strength requirements are lower, such as near the ends of the seat rails rather than in the central high-stress regions. This local placement allows displacement limitation without compromising the overall structural integrity of the rail system.
2Reliability
If conventional end stops are used, then displacement limitation is achieved, but undesirable distortion and bending under load occurs
Solution Approach 1:
The rail profile is pre-formed with specific geometric features (such as reinforced walls and optimized thickness distributions) that prepare the structure to resist distortion under load. This preliminary structural preparation prevents bending and instability when the end stops engage during operation.
3Reliability
If multiple limitation elements are arranged on the same part-region, then displacement limitation is improved, but manufacturing complexity and structural integrity worsen
Solution Approach 1:
The end stop combines multiple functions into a single integrated component: displacement limitation, structural reinforcement, and distortion prevention. This merging eliminates the need for separate limitation elements in the same region, reducing manufacturing complexity while maintaining all necessary functions.
Data Source
AI summary
A vehicle seat longitudinal adjuster (106) includes a seat track pair (1) with a lower seat track (2) and an upper seat track (4) that mutually engage one another for guided relative and longitudinal direction (x) movement. The lower seat track (2) has a substantially C-shaped profile (20, 22) with sections (24) that are bent downward at the ends. The upper seat track (4) has a substantially U-shaped profile (40, 42) with end sections (44) that are bent upward; the relative displaceability of the two seat tracks (2, 4) with respect to one another is limited by means of an interaction of an end stop (30) disposed on the lower seat track (2) with a stop element (48) disposed on the upper seat track (4), and wherein the end stop (30) is designed in the form of an extension of part of the downward bent sections (24) and the lower seat track (2) comprises a slotted hole (32) in the region of the end stop (30).