Polygonal Fastening Element Prevents Spindle Retainer Rotation
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Solution Overview
Problem
Existing seat rail designs for motor vehicles face issues with spindle retainer rotation during tightening, leading to spindle bending and potential functional impairments or failure due to friction between fastening bolts and the spindle retainer.
Innovation Solution
The seat rail features fastening openings and elements with a cross-section deviating from a circular shape, preferably polygonal, to securely lock the spindle retainer against rotation, using a connection rivet with a polygonal cross-section to prevent shifting and bending, and a peg for easy positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fastening bolt is used to secure the spindle retainer to the lower rail, then the spindle retainer can be fastened to the lower rail, but friction between the fastening bolt and spindle retainer causes rotation of the spindle retainer during tightening, leading to spindle bending
Solution Approach 1:
The fastening element is designed with an asymmetric polygonal cross-section (e.g., hexagonal) instead of a circular cross-section. This asymmetric geometry creates corresponding asymmetric fastening openings in both the spindle retainer and lower rail, preventing rotational movement of the spindle retainer during tightening while maintaining secure fastening.
2Strength
If a rivet connection is used to fasten the spindle retainer, then the spindle retainer is securely attached, but the rivet connection cannot prevent rotation of the spindle retainer during tightening of threaded floor connections
Solution Approach 1:
The rivet connection is enhanced with a polygonal cross-section fastening element (e.g., hexagonal rivet) that fits into corresponding polygonal fastening openings. This asymmetric design provides both secure attachment strength and prevents rotation of the spindle retainer during tightening operations.
3Ease of manufacture
If a circular cross-section fastening element is used, then the fastening element can be easily manufactured and installed, but it allows rotation of the spindle retainer with respect to the lower rail
Solution Approach 1:
The fastening element transitions from a circular cross-section to a polygonal cross-section (e.g., hexagonal). This change maintains ease of manufacture through standard forming processes while providing inherent anti-rotation stability through the asymmetric geometry that engages with corresponding polygonal fastening openings.
Data Source
AI summary
A seat rail for a motor vehicle seat includes a lower rail, which can be connected to a motor vehicle, and a spindle, which is arranged on the lower rail in a rotationally fixed manner by a spindle retainer. The spindle retainer is fastened to the lower rail by a fastening element extending through a fastening opening on the spindle retainer and a fastening opening on the lower rail. In order to provide a seat rail having a lower rail on which rotation of the spindle retainer is largely precluded, in particular in the event of a threaded floor connection extending through the spindle retainer, the fastening openings and/or the fastening element has a cross-section deviating from a circular shape, preferably a polygonal cross-section, in a connection section arranged in the region of the fastening openings.