Vehicle Seat Rail Assembly With Pivoting Rollers Under Load
Solution Overview
Problem
Existing rail arrangements for vehicle seats face issues with play-free operation due to overloading of guide elements, particularly rollers, leading to increased force requirements for seat adjustment, especially when the seat is reclined, as the upper rail can tilt or pivot within the lower rail.
Innovation Solution
A rail arrangement with positive locking contours and load-bearing rollers that allow the upper rail to pivot under load, ensuring consistent sliding force by engaging with support edges, preventing overloading and maintaining smooth adjustment in both upright and reclined positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If preload forces are increased to prevent play in the rail arrangement, then the upper rail remains stable and engaged with the lower rail, but the guide elements (rollers) become overloaded
Solution Approach 1:
The upper rail is segmented into a rail body and separate guide carriages that can pivot independently. This segmentation allows the guide carriages to tilt under load, enabling the rollers to disengage from the rail base and engage with support edges, thereby reducing roller overload while maintaining rail stability through the positive locking contours
Solution Approach 2:
The guide carriages are designed to be dynamically adjustable, allowing them to pivot or tilt relative to the rail body in response to applied loads. This dynamic adjustment enables the system to transition from a static engagement mode (rollers on rail base) to a load-adapted mode (rollers on support edges), resolving the contradiction between stability and roller strength
2Strength
If preload forces are reduced to protect guide elements from overloading, then the rollers are protected, but the front edge of the upper rail lifts off the bottom of the lower rail under load
Solution Approach 1:
By separating the upper rail into a rail body and pivotable guide carriages, the system allows the guide carriages to independently adjust their position under load. This segmentation enables the rollers to move onto support edges while the positive locking contours maintain overall rail engagement, preventing lift-off even with reduced preload
Solution Approach 2:
The support edges act as intermediaries between the rollers and the lower rail. When the guide carriages pivot under load, the rollers transition from contacting the rail base to contacting the support edges, which provide an alternative load path that maintains engagement without requiring high preload forces
3Stability of the object's composition
If the upper rail is constrained to prevent tilting, then engagement stability is improved, but the sliding force for seat adjustment increases
Solution Approach 1:
The system allows controlled dynamic tilting of the guide carriages during adjustment operations. This controlled movement reduces friction and engagement resistance during sliding, making adjustment easier, while the positive locking contours ensure that stability is restored and maintained during normal loaded operation
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 reliable and easy longitudinal seat adjustment in both upright and reclined positions without increased sliding force, even with reduced preload forces, by using positive locking contours and spring-mounted rollers to compensate for play and torque.
Implementation Method 1
The upper rail typically features load-bearing rollers as guide elements. These rollers run on a track base of the lower rail and essentially support the weight of the vehicle seat and any occupant against the lower rail.
Implementation Method 2
at least one load roller and at least one running roller are rotatably attached to each of the guide carriages
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a rail assembly (14) for a longitudinal seat adjustment system (10) of a vehicle seat (2), comprising a lower rail (16) for fastening to a vehicle floor and an upper rail (18) for coupling to the vehicle seat (2), the upper rail form-fittingly sitting in the lower rail, wherein: the upper rail (18) has a number of load rollers (42), by means of which the upper rail (18) is mounted for movement in a rail longitudinal direction (L) on a rail bottom (22) of the lower rail (16); the lower rail (16) has a profile longitudinal slot (26); the lower rail (16) and the upper rail (18) have mutually engaging form-fitting contours (28, 34); the form-fitting contours (34) of the upper rail (18) extend over the load rollers (42) and have a lead-through opening (48) in the region of each of the load rollers (42), through which the load rollers (42) at least partly extend or, when load is applied, can extend; and the lower rail (16) has support edges (50) which face the rail bottom (22) and are aligned with the load rollers (42) in the rail height direction (H).