Preloaded Rack-and-Slide Linear Drive for Play-Free Seat Adjustment
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Solution Overview
Problem
Existing linear drives for seat adjustment in motor vehicles face challenges in achieving play-free movement, adapting breaking loads, and maintaining performance over time due to wear, limiting their effectiveness and adaptability for new seat concepts.
Innovation Solution
A linear drive design featuring a toothed rack and movable slides with a compensation mechanism that preloads the operative contact between the slides and toothed rack, allowing for cyclic and out-of-phase movement to generate propulsion, while compensating for tolerances and wear through spring-loaded or preloaded contacts, ensuring smooth and low-noise operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional linear drives are designed to ensure play-free movement, then movement precision is improved, but device complexity and manufacturing effort increase significantly
Solution Approach 1:
The patent applies dynamics by making the toothed rack adjustable in its longitudinal position through a compensation means (such as a spring or adjustable mechanism). This allows the system to dynamically adapt to wear and tolerances, maintaining play-free movement without requiring overly complex precision manufacturing. The rack can be repositioned to compensate for wear, transforming a static precision problem into a dynamic adjustment solution.
Solution Approach 2:
The invention changes the parameter of the toothed rack's longitudinal position to compensate for wear and manufacturing tolerances. By allowing the rack position to vary within a certain range (defined by stops or limiting mechanisms), the system can adapt to different wear states and maintain optimal engagement with the slides, thereby achieving play-free movement without extreme manufacturing precision.
2Adaptability or versatility
If conventional linear drives are designed to adapt breaking loads, then load adaptability is improved, but device complexity and production effort increase
Solution Approach 1:
The toothed rack is designed with dynamic adjustability in its longitudinal position, allowing the engagement characteristics between the rack and slides to be modified. This dynamic adjustment capability enables the system to adapt to different breaking load requirements by changing the effective engagement geometry, providing load adaptability without requiring multiple specialized components for different load classes.
Solution Approach 2:
The adjustable toothed rack serves multiple functions: it provides the primary propulsion function, compensates for wear, and adapts to different breaking load requirements. This single component with adjustment capability replaces what would otherwise require multiple specialized components, reducing overall device complexity while maintaining versatility.
3Duration of action of stationary object
If conventional linear drives operate over time, then adjustment function is maintained, but wear causes loss of play-free movement and performance degradation
Solution Approach 1:
The compensation means is designed to be adjustable during the service life of the linear drive, allowing preliminary adjustments to be made before wear becomes problematic. The system includes adjustment mechanisms that enable the toothed rack position to be modified, effectively performing preliminary compensation that prevents performance degradation and extends service life while maintaining reliable play-free movement.
Solution Approach 2:
The system enables self-compensation for wear through its adjustable rack mechanism. The wear compensation can be performed by the system itself (or with minimal external intervention) by adjusting the rack position to maintain proper engagement with the slides, thereby self-correcting the effects of wear and maintaining movement quality throughout the service life.
4Productivity
If conventional linear drives are designed for high adjustment speed, then productivity is improved, but wear characteristics and movement smoothness deteriorate
Solution Approach 1:
The adjustable toothed rack allows optimization of engagement parameters such as contact pressure and engagement geometry. By adjusting the rack position, the system can maintain optimal parameters that enable high adjustment speeds while distributing loads more evenly to reduce wear, thus reconciling productivity with wear characteristics.
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 a compact, high-speed, and adaptable linear drive with improved wear characteristics and play-free movement, enhancing the service life and usability of the linear drive in various vehicle seat adjustment applications.
Implementation Method 1
the operative contact between at least one of the at least two slides and the at least one toothed rack is spring-loaded or preloaded
Implementation Method 2
the at least one compensation means spring-loads, in particular preloads, at least one of the at least two slides and/or the at least one toothed rack
Data Source
AI summary
The present invention relates to a linear drive (1) having at least one toothed rack (20) oriented along a longitudinal axis (L) and at least two slides (30) which are movable transversely to the longitudinal axis (L), and a drive shaft (60), wherein the at least two slides (30) are coupled to the drive shaft (60) in such a way that the at least two slides (30) each carry out at least one cyclic and out-of-phase movement in the course of one revolution of the drive shaft (60) and thereby push off by an operative contact at the at least one toothed rack (20) to generate propulsion in a direction of the longitudinal axis (L), wherein the linear drive (1) has at least one compensation means (15), by means of which the operative contact between at least one of the at least two slides (30) and the at least one toothed rack (20) is preloaded