Vehicle Seat Longitudinal Adjuster Spring Latching Stability
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Solution Overview
Problem
Existing longitudinal adjusters for vehicle seats lack mechanical stability, leading to potential deformation and distortion, and are limited in material choice due to inadequate locking mechanisms.
Innovation Solution
A longitudinal adjuster featuring a rail pair with a locking unit comprising a spring element, locking element, and actuating element, utilizing a plug-in/latching connection with preloading forces to ensure stability, allowing the upper rail to be made from high-strength materials and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spring element is connected to the upper rail by means of a riveted joint, then the longitudinal adjuster can be manufactured, but the mechanical stability is insufficient leading to deformation and distortion
Solution Approach 1:
The connection between the spring element and upper rail is segmented into two distinct functional parts: a latching nose that engages with a latching aperture for positioning, and a latching tab that engages with a separate securing aperture for locking. This segmentation allows each part to perform its specific function optimally without compromising overall mechanical stability.
Solution Approach 2:
The spring element is preloaded through the latching mechanism before the adjuster is put into service. The latching nose and tab are designed to engage with the apertures in a predetermined sequence during assembly, ensuring that the spring element is correctly positioned and secured before any operational loads are applied, thereby preventing deformation.
2Strength
If the upper rail is made from high-strength material, then the strength is improved, but the connection method must also be improved to prevent distortion
Solution Approach 1:
The connection interface is segmented into distinct latching and securing features that distribute loads across multiple engagement points. The latching nose engages with one aperture while the latching tab engages with another, creating a distributed connection system that prevents stress concentration and distortion of the high-strength upper rail.
Solution Approach 2:
The spring element connection features (latching nose and tab) are designed with specific local geometries that match the apertures in the upper rail. The latching nose has a width designed to fit within the latching aperture dimensions, while the latching tab is sized for the securing aperture, creating localized optimal connections that prevent distortion while utilizing the full strength of the high-strength material.
3Stability of the object's composition
If a plug-in/latching connection is used, then mechanical stability is improved, but the device complexity increases
Solution Approach 1:
The latching nose and latching tab are merged into a single integrated spring element component. This integration allows the spring element to provide both the latching function (through the nose) and the securing function (through the tab) simultaneously, reducing the number of separate parts while maintaining mechanical stability.
Solution Approach 2:
The plug-in/latching connection is designed to be self-aligning and self-securing. The latching nose automatically engages with the latching aperture when the spring element is inserted, and the latching tab subsequently engages with the securing aperture, creating a stable connection without requiring additional fastening operations or complex assembly procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides improved mechanical stability and allows for the use of high-strength materials, ensuring reliable locking and reduced mechanical noise during operation.
Implementation Method 1
the spring element applies a preloading force to the actuating element and to the locking element
Data Source
AI summary
A longitudinal adjuster (3) for a vehicle seat (1) includes at least one rail pair (7), including a lower rail (9) and an upper rail (11), which can be moved longitudinally in relation to the lower rail (9). At least one locking unit (13) locks the upper rail (11). At least one actuating element (5) releases the locking of the upper rail (11). The locking unit (13) includes at least one locking element (15) and at least one spring element (17), which are operatively engaged with each other. The spring element (17) is interlockingly and frictionally connected to the upper rail (11) by an insertion locking connection (S). The spring element (17) applies a preloading force to the actuating element (5) and to the locking element (15). A vehicle seat (1) is also provided with at least one such longitudinal adjuster (3).