Power Seat Slide Screw Support for Stable, Quiet Rail Motion
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Solution Overview
Problem
Existing power seat slide apparatuses face issues with irregular sliding and rotation of the screw shaft due to rigid fixation of the worm wheel and screw shaft, leading to noise and difficulty in supporting long screw shafts, as well as structural challenges in withstanding loads during sudden vehicle stops.
Innovation Solution
A power seat slide apparatus featuring a screw member supported by both the upper and lower rails, with slide nut members and a retaining bracket to stabilize the screw shaft, and a drive unit that transmits rotational force through a reduction gear mechanism, ensuring stable sliding and rotation without engaging noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the worm wheel and screw shaft are rigidly fixed and the screw shaft is supported by the worm wheel and nut member, then the structure is simplified, but it becomes difficult to securely support long screw shafts, causing irregular sliding motion and rotation
Solution Approach 1:
The support structure for the screw shaft is segmented into multiple independent support points: the worm wheel provides rotational support while the separate retaining bracket provides lateral support. This segmentation allows each component to perform its specific support function independently, preventing irregular motion while maintaining structural simplicity.
Solution Approach 2:
The retaining bracket acts as an intermediary component that mediates between the screw shaft and the upper rail. It provides the necessary lateral support to the screw shaft without interfering with the worm wheel's rotational function, thereby preventing irregular sliding and rotation while keeping the overall structure simple.
2Reliability
If the gear box is designed to withstand loads during sudden vehicle stops, then reliability is improved, but the gear box size and structural complexity increase
Solution Approach 1:
The load-bearing function during sudden stops is extracted from the gear box and transferred to the retaining bracket and screw shaft-nut member system. The retaining bracket is specifically designed to absorb longitudinal loads, allowing the gear box to be simplified in structure and size while maintaining overall system reliability.
Solution Approach 2:
Instead of designing the gear box to withstand all loads including sudden stops, the design inverts the approach by having the retaining bracket and screw shaft-nut member system bear the longitudinal loads. This allows the gear box to be optimized for its primary function of transmitting rotational drive force, reducing its structural complexity.
3Stability of the object's composition
If the screw shaft is made longer to span between support points, then structural rigidity is improved, but it becomes more difficult to support securely and causes interaction between worm wheel and screw shaft engagements
Solution Approach 1:
The support function is segmented between the worm wheel (providing rotational support) and the retaining bracket (providing lateral support at intermediate points). This segmentation allows the screw shaft to be adequately supported without requiring excessive length, preventing engagement instability while maintaining structural rigidity.
Solution Approach 2:
The retaining bracket serves as an intermediary support element that prevents excessive deflection of the screw shaft without creating interference with the worm wheel engagement. It provides the necessary structural support to maintain engagement stability while allowing the screw shaft to maintain appropriate length for rigidity.
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 stable and silent sliding of the seat, reduces noise during operation, and simplifies the gear box structure by allowing load transmission directly to the lower rail, enhancing the rigidity of the screw member and reducing the size and weight of the gear box.
Implementation Method 1
a screw member supported by the upper rail and the lower rail, a feed nut member arranged on one of the lower rail and the upper rail and threaded onto the screw member
Implementation Method 2
a first slide nut member and a second slide nut member arranged on the screw member so as to oppose each other via the retaining bracket and cooperatively sandwiching the retaining bracket in an axial direction of the screw member
Data Source
AI summary
A power seat slide apparatus includes a lower rail adapted to be provided on a floor of a vehicle, an upper rail slidably supported by the lower rail and adapted to support a seat for a vehicle, a screw member supported by the upper rail and the lower rail, a feed nut member arranged on one of the lower rail and the upper rail and threaded onto the screw member, a retaining bracket arranged on the other one of the lower rail and the upper rail and the screw member being positioned in the retaining bracket, a first engaging member and a second engaging member arranged on the screw member so as to oppose each other via the retaining bracket and cooperatively sandwiching the retaining bracket in an axial direction of the screw member, and a drive unit transmitting a rotating drive force to the screw member.