Large-Stroke Electric Headrest Structure to Prevent Lead Screw Locking
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Solution Overview
Problem
Conventional car seat headrests with increased adjustment stroke are prone to lead screw locking due to manufacturing accuracy and tolerance issues, leading to operational failures.
Innovation Solution
A large-stroke electric headrest structure featuring an elastic energy-absorbing plate between the driving motor and supporting plate, allowing the motor to tilt and deflect, coupled with non-coaxial alignment of threaded and vertical through-holes, preventing locking and enabling smooth sliding motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a motor is disposed between the seat cushion and the seat back, then the motor can drive the seat back relative to the seat cushion to adjust the reclining angle, but the motor occupies valuable internal space of the seat and increases device complexity
Solution Approach 1:
The patent moves the motor from the internal space between seat cushion and seat back to the external side of the seat back. This spatial relocation resolves the contradiction by eliminating the conflict between motor placement and internal space utilization, while still achieving the desired seat reclining adjustment function through the connection mechanism between the motor-driven rod and seat back
2Adaptability or versatility
If the motor is disposed between the seat cushion and the seat back, then the reclining function can be achieved, but the adjustment range is limited and the structure becomes complex
Solution Approach 1:
The patent divides the seat assembly into distinct modular components: seat cushion, seat back, motor assembly, and connection rod. This segmentation allows the motor to be positioned externally while maintaining functional connection, thereby expanding adjustment range without proportionally increasing overall structural complexity
Solution Approach 2:
The connection rod serves as an intermediary element between the motor and the seat back. It transmits the motor's rotational motion to the seat back while allowing for greater movement range, thus expanding adaptability without requiring direct motor-to-seat-back integration that would limit range
3Ease of operation
If the motor is disposed between the seat cushion and the seat back, then the reclining mechanism can function, but it interferes with the airbag structure and reduces safety
Solution Approach 1:
The patent extracts the motor from the internal space between seat cushion and seat back and relocates it to the external side of the seat back. This extraction eliminates the interference between the motor and airbag structure, resolving the safety contradiction while preserving the reclining mechanism's functionality through the external connection rod arrangement
Data Source
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AI summary
A large-stroke electric headrest structure for a car seat, comprising: two guide rods (1) that are disposed in a same direction; a headrest body (2) externally connected with a slider (21), the slider (21) being provided with two through holes for the guide rods and a threaded through-hole all of which are disposed vertically, and the two guide rods (1) being disposed slidably in the two through holes, respectively; a supporting plate (3) connected to the two guide rods (1) and provided with a vertical through hole (d) aligned with the threaded through-hole; and a driving motor (4) mounted in a tiltable manner on a side of the supporting plate (3) away from the slider (21), wherein an elastic energy-absorbing plate (41) is padded between the driving motor (4) and the supporting plate (3), the driving motor (4) is connected in a transmission manner with a lead screw (42) movably inserted in the vertical through hole (d), an end of the lead screw (42) away from the driving motor (4) is screwed in the threaded through-hole, and a gap is reserved between the vertical through hole (d) and the lead screw (42).