Articulated Head Restraint Linkage for Quiet Gap-Free Motion
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Solution Overview
Problem
Existing powered head restraints for vehicle seats face issues such as vibration and noise due to gaps between guide pins and holes, and difficulties in assembly and movement caused by manufacturing tolerances and temperature changes.
Innovation Solution
A powered head restraint system that includes a front-back moving unit, a motor, a lead screw, a lifting nut, a guide unit, and a pivot link unit, where the lifting nut is connected to the lead screw and the front-back moving unit via a pivot link unit, and a tension spring is used to pull the front-back moving unit towards the guide unit, ensuring reliable operation and reducing gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If guide pins and guide holes are used for forward and backward movement, then the structure is simple, but gaps occur causing vibration and noise
Solution Approach 1:
A tension spring is introduced as an intermediary component between the guide pin and guide hole assembly. The spring applies continuous tension to eliminate gaps while maintaining the simple guide pin-hole structure, thus resolving the contradiction between structural simplicity and operational stability.
Solution Approach 2:
The physical state of the connection is changed from rigid fixed positioning to elastic tensioned positioning. By changing the parameter of connection force from static to dynamically adjustable elastic force, the system eliminates gaps without increasing structural complexity.
2Manufacturing precision
If manufacturing tolerance is reduced to ensure correct assembly, then assembly precision improves, but the guide pin becomes tightly inserted and difficult to move
Solution Approach 1:
The connection parameter is changed from rigid interference fit to elastic tension fit. The tension spring allows the guide pin to move smoothly within the guide hole by providing a controlled elastic force that overcomes friction without requiring loose tolerances.
Solution Approach 2:
The tension spring acts as a mediator that decouples the relationship between manufacturing tolerance and movement smoothness. It compensates for tolerance variations while maintaining consistent movement characteristics.
3Ease of operation
If manufacturing tolerance is increased to allow movement, then ease of operation improves, but gaps are generated causing vibration and noise
Solution Approach 1:
The tension spring serves as a compensating intermediary that eliminates gaps created by increased tolerances. It maintains consistent contact between guide components while allowing smooth movement, thus preserving both ease of operation and operational stability.
4Adaptability or versatility
If guide hole dimensions are modified to accommodate temperature changes, then adaptability to temperature improves, but the guide hole may block forward and backward movement
Solution Approach 1:
The tension spring acts as a buffer that compensates for dimensional changes in the guide hole due to temperature. It maintains consistent tension and contact pressure regardless of hole dimension variations, ensuring smooth movement across temperature ranges.
Solution Approach 2:
The system transitions from static rigid positioning to dynamic elastic positioning. The tension spring dynamically adjusts to temperature-induced dimensional changes while maintaining operational smoothness through its elastic properties.
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 system provides a reliable and smooth forward and backward operation of the powered head restraint, reducing vibrations and noise, and maintaining performance despite manufacturing tolerances and temperature variations.
Implementation Method 1
a lead screw installed on the motor, a lifting nut fastened to the lead screw
Implementation Method 2
a tension spring pulling the front-back moving unit to a guide unit
Data Source
AI summary
The present disclosure relates to a powered head restraint for vehicle seat back. In particular, the present disclosure relates to a powered articulated head restraint for vehicle seat back moving back and forth without a combination of guide pins and guide holes or a combination of guide pins and guide long holes.