Headrest Holder Assembly Using Asymmetric Fitting Geometry
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Solution Overview
Problem
The existing headrest support structures in automobile seats require separate components for left and right headrest holders, leading to increased manufacturing costs and reduced productivity due to the need for distinct designs and assembly methods.
Innovation Solution
A headrest support structure that allows for the common use of headrest holders by utilizing asymmetric transverse cross-sections and line symmetrical fitting holes, ensuring correct assembly and positioning without the need for special jigs, and incorporating a locking mechanism for vertical adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate left and right headrest holders are used, then correct assembly position is ensured, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The headrest holder is designed with an asymmetric transverse cross-section where one side has a different shape than the other. This asymmetry allows a single unified holder design to be correctly positioned in either the left or right fitting hole without requiring separate left and right holders, thereby improving productivity while maintaining assembly precision
Solution Approach 2:
The headrest holder is designed as a universal component that can be installed in both left and right positions. By making the holder structure common to both sides with appropriate asymmetric features, the design eliminates the need for separate left and right holders, reducing part variety and improving manufacturing efficiency
2Manufacturing precision
If separate left and right headrest holders are used, then correct assembly is ensured, but device complexity increases
Solution Approach 1:
The design merges the left and right headrest holder designs into a single unified holder type. By combining the functions of both left and right holders into one asymmetric design, the component variety is reduced while assembly correctness is maintained through the asymmetric fitting features
Solution Approach 2:
The asymmetric transverse cross-section of the holder creates inherent directional features that ensure correct installation orientation. This asymmetry allows the same holder design to be used on both sides while preventing incorrect installation, thereby reducing device complexity without sacrificing assembly correctness
3Manufacturing precision
If special jigs are used for assembly, then correct positioning is achieved, but manufacturing cost increases
Solution Approach 1:
The asymmetric design of the headrest holder and fitting hole creates a self-aligning system where the holder automatically positions itself correctly during installation. This self-service positioning mechanism eliminates the need for special assembly jigs, reducing manufacturing cost while maintaining positioning accuracy
Data Source
AI summary
A headrest support structure of a conveyance seat includes: an upper frame that is provided with a pair of fitting holes and that constitutes a back frame; and a pair of cylindrical headrest holders, each of which fits in one of the pair of fitting holes to be fixed to the upper frame. A transverse cross-section of a fitting portion of each headrest holder fitting in the corresponding fitting hole has an asymmetric shape about a fitting axis parallel to a fitting direction in which the headrest holder fits in the fitting hole, the transverse cross-section being a cross-section in a direction orthogonal to the fitting axis. The pair of fitting holes is formed such that each headrest holder is allowed to fit in only one of the pair of fitting holes provided at a position set as a fixing position of the headrest holder.