Tilting Motor 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 locking of the lead screw due to accuracy and manufacturing tolerance issues, leading to motor failure.
Innovation Solution
A large-stroke electric headrest structure featuring guide rods, a slider, a supporting plate, and a tiltable driving motor connected via a lead screw, with an elastic energy-absorbing plate to prevent locking by allowing the motor to tilt and absorb manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the adjustment stroke of the headrest is increased, then the headrest adjustment range is improved, but the lead screw is prone to locking due to accuracy and manufacturing tolerance issues
Solution Approach 1:
The driving motor is designed to be tiltable relative to the supporting plate, transforming from a fixed rigid connection to a dynamic adjustable connection. This allows the motor to tilt and follow the lead screw's movement trajectory, maintaining proper alignment throughout the extended adjustment stroke and preventing lead screw locking due to misalignment.
Solution Approach 2:
The elastic energy-absorbing plate is introduced to change the mechanical parameters of the connection between the driving motor and supporting plate. This elastic element allows for parameter adjustment in terms of motor tilt angle and position, accommodating manufacturing tolerances and maintaining smooth operation over the extended stroke range.
2Length of moving object
If the adjustment stroke is increased beyond conventional limits, then the user comfort and functionality are improved, but the motor may become locked and unable to rotate
Solution Approach 1:
The driving motor is mounted in a tiltable manner on the supporting plate, allowing it to dynamically adjust its position and orientation. This dynamic mounting enables the motor to follow the lead screw's movement, maintaining proper alignment and ensuring smooth rotation throughout the extended adjustment stroke range.
Solution Approach 2:
The elastic energy-absorbing plate serves as an intermediary element between the driving motor and the supporting plate. It mediates the mechanical connection, allowing for relative movement and tilt accommodation, which prevents motor locking and maintains ease of operation over the extended stroke.
3Device complexity
If a rigid fixed connection is used between the motor and supporting plate, then the structure is simple, but the motor cannot accommodate misalignment and tilts cause locking
Solution Approach 1:
The motor mounting structure transitions from a rigid fixed connection to a dynamic tiltable connection. The motor can tilt and move relative to the supporting plate, accommodating misalignment caused by manufacturing tolerances and maintaining reliable operation throughout the adjustment stroke.
Solution Approach 2:
The elastic energy-absorbing plate enables parameter changes in the motor's position and orientation relative to the supporting plate. This allows the system to adapt to misalignment conditions while maintaining a relatively simple overall structure.
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
Enables smooth sliding and a large-stroke adjustment range of over 100 mm while preventing motor lockage, with a simple assembly design.
Implementation Method 1
an elastic energy-absorbing plate padded between the driving motor and the supporting plate, and when the threaded through-hole and the vertical through hole are not disposed coaxially, the driving motor is tilted to press the elastic energy-absorbing plate to cause deflection of the elastic energy-absorbing plate
Data Source
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).