Motor Vehicle Headrest Spring Steel Bearing Design
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Solution Overview
Problem
The existing motor vehicle seat headrests face issues due to dimensional dispersions in spring steel wire bearings, leading to variable clamping forces and potential pinching that impairs smooth sliding and causes permanent deformation over time, affecting the sliding mechanism and durability.
Innovation Solution
The headrest design includes U-shaped spring steel wire bearings with free end parts that bear against molded stops to absorb pinching force and a middle part positioned at least 15mm away from the rod axis to prevent deformation, providing a sufficient lever arm to maintain consistent pinching force and prevent permanent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the spring arms are positioned close to the rod to reduce lever arm, then the pinching force is increased, but permanent deformation occurs over time weakening the pinch force
Solution Approach 1:
The patent introduces a new spatial dimension by positioning the spring arms at a distance of at least 15mm from the rod axis, creating a lever arm that was previously avoided. This dimensional change transforms the force application mechanism, allowing the spring to maintain pinching force through rotational moment rather than direct contact, thereby preventing permanent deformation while sustaining the required pinching force.
2Force
If the branches are positioned closer together than nominal distance, then the clamping force is increased, but excessive pinching impairs smooth sliding of the rod
Solution Approach 1:
The patent introduces stops as intermediary elements that mediate between the spring branches and the rod. These stops limit the maximum pinching force by preventing the spring arms from contacting the rod when branches are too close together, thereby maintaining adequate clamping force while preventing excessive pinching that would impair smooth sliding.
3Reliability
If dimensional variations in spring steel wire are reduced, then consistent clamping force is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the critical parameter from the spacing between spring arms (which requires high manufacturing precision) to the distance from the rod axis (which can be more easily controlled). By specifying that the spring arms be positioned at least 15mm from the rod axis rather than controlling the exact distance between arms, the design achieves consistent clamping force while reducing manufacturing precision requirements.
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
This design ensures consistent sliding force and prevents permanent deformation, enhancing the durability and reliability of the headrest by limiting excessive pinching and maintaining the pinching force over time.
Implementation Method 1
each of said bearings being provided with a spring in the form of a metal wire of spring steel bent to present a general U shape, the arms of the U bearing on each of said tabs so as to pinch said rods between said tabs
Implementation Method 2
the free extreme parts of said branches are arranged so as to be able to bear on stops made from the molding of said bearing concerned, so that said stops can take up part of the pinching force exerted by said branches
Data Source
Figure 1a~1b
Figure 2~3
Figure 4
AI summary
Headrest (1) of motor vehicle seat, comprising a housing (3) having two conduits (4) receiving one of the rods (2) in sliding motion, being provided with an upper bearing (5a) and a lower bearing (5b) having at their periphery two flexible tabs (6) opposed in a first direction (7), each of said bearings being provided with a spring (8) in the general shape of a U, the arms (9) bearing on each of said tabs so as to pinch said rods between said tabs, the free extreme parts (15) of said arms are arranged so as to be able to bear on stops (16), the middle part (17) of said spring being arranged so that the gap (21) between the axis (18) and the axis (19) is greater than or equal to 15 mm.