Spring-Loaded Gearbox Assembly for Stable Seat Rail Mesh Engagement
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Solution Overview
Problem
Existing vehicle seat positioning systems with power adjustment capabilities face challenges due to tolerance stack-up, dimensional variations, and vibrations, which affect the mesh engagement between the drive wheel and gear rack, leading to inconsistent performance and engagement issues.
Innovation Solution
A long rail assembly incorporating a spring-loaded gearbox assembly that is fixedly coupled to the power rail drive assembly, featuring a drive wheel rotated by the gearbox to ensure meshingly engaged position with the fixed long rail, providing torque and biasing the drive wheel towards an engaged position with the gear rack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed gear rack and drive wheel system is used for power seat adjustment, then the seat positioning function is achieved, but tolerance stack-up and dimensional variations cause inconsistent mesh engagement
Solution Approach 1:
The gearbox is mounted on a sliding mechanism that allows it to move dynamically along the long rail. This dynamic positioning enables the gearbox and drive wheel to self-align with the gear rack, compensating for tolerance stack-up and dimensional variations in real-time, thereby ensuring consistent mesh engagement despite manufacturing variations.
Solution Approach 2:
The system changes the positional parameter of the gearbox along the long rail through sliding movement. By allowing the gearbox position to vary within a certain range, the system can adapt to dimensional variations in the gear rack and drive wheel, maintaining proper mesh engagement conditions despite manufacturing tolerances.
2Reliability
If a rigid drive wheel-gear rack connection is used, then power transmission is efficient, but vibrations from road input cause disengagement
Solution Approach 1:
The sliding mounting mechanism provides dynamic adjustment capability, allowing the gearbox to move in response to vibration forces. This dynamic response enables the system to maintain engagement during road vibrations by permitting controlled movements that prevent disengagement while preserving power transmission efficiency.
Solution Approach 2:
The sliding mechanism acts as a cushioning element that absorbs and accommodates vibration impacts before they can cause disengagement. By providing a compliant mounting structure, the system prepares for and mitigates the harmful effects of road vibrations, maintaining reliable engagement under dynamic conditions.
3Reliability
If precise dimensional control is implemented for all components, then mesh engagement consistency improves, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of requiring all components to be manufactured with extremely tight tolerances, the system uses dynamic sliding adjustment to compensate for normal manufacturing variations. This approach achieves reliable engagement consistency through operational adaptability rather than through stringent manufacturing precision requirements, thereby reducing manufacturing complexity.
Solution Approach 2:
The sliding mechanism serves as an intermediary between the gearbox and the long rail, providing a degree of freedom that allows the system to accommodate dimensional variations. This intermediary element enables the use of standard manufacturing tolerances while still achieving consistent engagement, avoiding the need for complex high-precision manufacturing across all 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 spring-loaded gearbox assembly maintains consistent engagement between the drive wheel and gear rack, compensates for dimensional variations, and ensures engagement even under road vibrations, providing reliable and stable power adjustment of the vehicle seat.
Implementation Method 1
a spring biasing the gearbox within the mounting bracket such that the drive wheel is meshingly engaged with the fixed long rail
Data Source
AI summary
A long rail assembly for use in an automotive vehicle includes a fixed long rail and a power rail drive assembly having a drive wheel for transposing the power rail drive assembly along the fixed long rail. The power rail drive assembly includes an upper channel, a spring-loaded gearbox assembly fixedly coupled to the upper channel, and the drive wheel fixedly coupled to a drive shaft projecting from the spring-loaded gearbox assembly and rotated by the spring-loaded gearbox assembly for transposing the power rail drive assembly along the fixed long rail. The spring-loaded gearbox assembly includes a mounting bracket fixedly coupled to the upper channel, a gearbox repositionable within the mounting bracket, and a spring biasing the gearbox within the mounting bracket such that the drive wheel is engaged with the fixed long rail.