Motorized Folding Head Restraint for Quiet Return Positioning
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Solution Overview
Problem
Existing head restraint positioning mechanisms in vehicles often experience noise due to component vibration ('chuck') and lack automated positioning options, which are desired by users of higher-end vehicles.
Innovation Solution
An electrically powered return-folding head restraint assembly with a post assembly, cross member, and internal gear mechanism that allows the head restraint to move between upright and tilted positions using a motor-driven gear system, reducing 'chuck' noise and enabling automated positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a manual positioning mechanism is used, then the device complexity is reduced, but the ease of operation deteriorates due to lack of automation
Solution Approach 1:
The patent applies nesting by placing the motor and gear mechanism inside the head restraint bun itself. The motor is positioned within the bun, and the gear system is compactly arranged with concentric gears (second gear concentrically fixed to third gear) to minimize space requirements. This allows automated positioning functionality to be integrated into the existing head restraint structure without requiring additional external components.
2Object-generated harmful factors
If traditional gear mechanisms are used, then the ease of manufacture is improved, but object-generated harmful factors worsen due to chuck noise from vibrating components
Solution Approach 1:
The patent addresses chuck noise by modifying the gear engagement characteristics. The angled first gear (0-30 degrees from perpendicular to second gear axis) creates smoother, more gradual tooth engagement that reduces impact vibrations. The worm gear mechanism also provides inherent damping through its sliding contact geometry, reducing the amplitude and frequency of vibrations that cause chuck noise while maintaining manufacturable gear designs.
3Ease of operation
If the head restraint is made more positionable with automated control, then the ease of operation is improved, but the use of energy increases due to motor operation
Solution Approach 1:
The patent implements partial action by providing automated positioning capability only when needed, rather than continuous operation. The motor activates selectively to move the head restraint between upright and folded positions, then remains idle. This selective activation minimizes energy consumption while maintaining ease of operation, as the system performs automated positioning only during position transitions rather than continuously.
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 solution provides quiet and automated positioning of the head restraint, enhancing user experience by minimizing noise and allowing for convenient adjustment between upright and tilted positions.
Implementation Method 1
an electric motor that rotates the worm in a clockwise or counter-clockwise direction
Implementation Method 2
a spur gear that is driven by rotation of the worm
Implementation Method 3
a first helical gear that is concentrically fixed to the spur gear, and a second helical gear fixed to the cross member
Data Source
AI summary
A head restraint assembly includes a post assembly which has a first post section, a second post section, and a cross member section connecting the first post section and the second post section. The first post section and the second post section are adapted to engage a vehicle seat. The head restraint includes a bun moveably attached to the post assembly, a first gear, and a motor that rotates the first gear in a clockwise or counter-clockwise direction. Rotation of the first gear drives a second gear which drives a third gear. Rotation of the second gear in a first direction causes movement of the bun to a tilted position while movement of the second gear in a second direction causes movement of the bun to an upright position.