Vehicle Seat Rail Drive With Resilient Worm Wheel Support
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Solution Overview
Problem
Existing longitudinal adjustment devices for vehicle seats, particularly those with integrated motor-gear units, face inefficiencies due to high friction and unsynchronized adjustments, which affect comfort and performance.
Innovation Solution
A longitudinal adjustment device with a rail arrangement featuring a drive device that includes a motor, a gear unit, a spindle with a spindle thread, and a spindle bearing, where the worm wheel and spindle nut are supported in an axially resilient manner via axial ball bearings and axial bearing bushes, allowing for low-friction movement and compensation for axial tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the worm wheel and spindle nut are supported in a fixed manner, then the structure is simple, but friction is high and adjustment is unsynchronized
Solution Approach 1:
The worm wheel and spindle nut are supported in an axially resilient manner instead of a fixed manner, allowing dynamic adaptation to tolerances and reduced friction during adjustment operations
Solution Approach 2:
The support characteristics of the worm wheel and spindle nut are changed from fixed to axially resilient, modifying the mechanical parameters to achieve both low friction and synchronized adjustment
2Loss of energy
If axial ball bearings are used to support the worm wheel and spindle nut, then friction is reduced, but device complexity increases
Solution Approach 1:
Axial ball bearings are introduced as intermediary elements between the worm wheel/spindle nut and the gear housing, mediating the interaction to reduce friction while maintaining manageable complexity through standardized components
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 enables efficient, low-friction rail adjustment with synchronized movement, reducing frictional losses and enhancing comfort by compensating for different adjusting movements and preventing unwanted nonsynchronous adjustments.
Implementation Method 1
the worm wheel and/or the spindle nut are/is supported, in particular rotatably supported, in the gear housing in an axially resilient manner and in the axial direction, on the one hand via at least one axial ball bearing
Implementation Method 2
the axial ball bearing and thus the ball cage ring are preferably arranged directly between the worm wheel/the spindle nut and the spring washer
Data Source
AI summary
A longitudinal adjustment device may have one rail arrangement and one drive device for the rail arrangement. The rail arrangement may have a first rail, and a second rail guided movably on the first rail. The drive device may have at least one motor, a gear unit supported in the second rail, a spindle with a spindle thread, and a spindle bearing. The gear unit may have a drive worm drivable by the motor, and a worm wheel, which is in operative connection with the worm teeth. The drive worm and the worm wheel are supported in a gear housing. The worm wheel is supported in the gear housing in an axially resilient manner and in the axial direction, on the one hand via an axial ball bearing and on the other hand via an axial bearing bush.