Vehicle Headrest Support Rod Recess Forming
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Solution Overview
Problem
Headrest support rods in vehicle seats face safety issues during rear-end collisions due to twisting and deformation, leading to potential separation of the headrest from the seat, which compromises safety as the locking wire can unwind from the notch, especially under high acceleration forces.
Innovation Solution
A method for producing a tubular body with a recessed surface for the headrest support rod using cold forming techniques, involving plate-shaped semi-finished products that are formed into blanks with convex shapes, allowing for the introduction of depressions with controlled depth and width, and subsequent joining of shell-shaped segments to create a tubular body with uniform thickness and small radii, preventing material cracking and ensuring secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the notch is pressed directly into the support rod to avoid creating an opening, then the structural integrity is improved, but the notch depth is limited by material flow into the tube
Solution Approach 1:
The recess is formed in the blank before the tubular body is closed, allowing deep recesses to be created without material flow restrictions that would occur if pressing into a closed tube. This preliminary action enables achieving the required notch depth while maintaining structural integrity.
2Reliability
If the locking sections are cut into the headrest support to create an undercut, then the locking capability is improved, but an opening or crack is created that acts as a stress concentration
Solution Approach 1:
The recess with undercut geometry is formed in the blank before closing into a tube. This allows the locking sections to be created with the necessary undercut shape for reliable locking, while avoiding the creation of openings or cracks that would occur with post-forming cutting operations.
Solution Approach 2:
The blank is divided into first and second shell-shaped segments that are joined to form the tubular body. This segmentation allows the recess to be formed in the open blank structure, enabling complex geometries without creating stress-concentrating cracks.
3Stability of the object's composition
If the seat structure is stiffened to prevent excessive twisting, then the stability is improved, but the weight significantly increases
Solution Approach 1:
The recess is formed in the blank before closing, allowing the locking geometry to be created without requiring additional stiffening of the seat structure. The headrest support maintains its locking capability through the pre-formed recess geometry rather than through structural stiffening.
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 method enhances vehicle safety by preventing the headrest from detaching during accidents by ensuring the tubular body remains securely locked, maintaining the headrest's position and reducing the risk of material failure due to stress concentration.
Implementation Method 1
forming the semi-finished product into a blank having a convex shape, an outer surface, and an inner surface
Implementation Method 2
Incorporating at least one recess having a predetermined width and depth into the outer surface of the blank by means of cold forming during or after step b)
Implementation Method 3
Joining the first segment and the second segment according to step e1) to form the tubular body by connecting the edges of the first segment and the second segment along at least two seams
Data Source
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AI summary
A method for manufacturing a tubular body (10) suitable as a support rod (200) for carrying a headrest (210) of a vehicle seat (220), wherein the tubular body (10) has a lateral surface (11) provided with at least one recess (30) and is used in particular for a vehicle (1), characterized by the following method steps: a) providing at least one plate-shaped semi-finished product (20); b) forming the semi-finished product (20) into a blank (21); c) introducing at least one recess (30) into the blank (21) during or after step b); d) producing a first shell-shaped segment (40) having two edges (41, 42) from the blank (21) after step c); e) producing a second shell-shaped segment (50) having two edges (51, 52) from the blank (21) after step b) or c); f1) Joining the first segment (40) and the second segment (50) after step e1) to form the tubular body (10).Furthermore, the invention relates to a support bar for carrying a headrest of a vehicle seat, as well as a headrest, a vehicle seat and a vehicle with such a support bar.