Vehicle Seat Longitudinal Adjuster Crash Load Transmission
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Solution Overview
Problem
Existing longitudinal adjusters for vehicle seats have a high number of openings on the surface, which can compromise stability and increase the risk of metal noises during normal operation, and are inadequate in safely transmitting crash loads to the vehicle structure.
Innovation Solution
A longitudinal adjuster design featuring a pair of rails with a spindle nut and spindle that forms an inner channel, where a crossbar is accommodated in a slot with a circumferential gap, allowing the spindle to pass through without contact, and a shoulder to jam the crossbar between the rail and shoulder upon a predetermined force, effectively transmitting forces to the second rail during crashes, while minimizing noise and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the spindle is passed through the first crossbar with contact, then the structure is more rigid, but metal noises occur during normal operation
Solution Approach 1:
A bearing bush is introduced as an intermediary element between the spindle and the first crossbar. The bearing bush allows the spindle to rotate smoothly without direct metal-to-metal contact, eliminating noise while maintaining structural support. This mediator resolves the contradiction by providing both stability and noise reduction.
2Ease of manufacture
If multiple openings are provided in the seat rail surface, then assembly is easier, but stability and noise resistance are compromised
Solution Approach 1:
The first crossbar is segmented into multiple parts: the main crossbar body, bearing bushes at each end, and sealing elements. This segmentation allows for easier assembly through modular installation while maintaining the integrity and stability of the seat rail surface, as each component can be independently positioned and secured.
3Adaptability or versatility
If the crossbar is freely movable, then adjustment range is increased, but crash load transmission is inadequate
Solution Approach 1:
The system dynamically transitions between two states: during normal operation, the bearing bushes allow free rotation and adjustment of the spindle for enhanced adaptability; during crash conditions, the shoulder on the spindle engages with the first crossbar to create a rigid connection for reliable load transmission. This dynamic behavior resolves the contradiction between adjustability and safety.
Solution Approach 2:
The shoulder on the spindle is pre-positioned to engage with the first crossbar at predetermined locations. This preliminary arrangement ensures that when crash forces are applied, the load transmission path is immediately activated without requiring additional activation mechanisms, thereby ensuring reliability while maintaining normal adjustability.
4Reliability
If the spindle is fixed in position, then crash load transmission is improved, but normal operation noise increases
Solution Approach 1:
The spindle system is designed to be dynamically configurable: during normal operation, the bearing bushes enable smooth rotation minimizing noise; during crash events, the shoulder engagement creates a fixed position for reliable load transmission. This dynamic design resolves the contradiction by providing both noise-free operation and crash safety.
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 design reduces the number of surface openings, minimizes metal noise during normal operation, and ensures safe transmission of crash loads to the vehicle structure by effectively jamming the crossbar between the rail and shoulder, enhancing the vehicle seat's stability and safety.
Implementation Method 1
a bearing bush is arranged in the bearing opening, wherein the bearing bush is made of a plastic
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a longitudinal adjuster (10), comprising at least one pair of rails, which is formed of a first seat rail (12) and a second seat rail (14), which is displaceable in a longitudinal direction (x) relative to the first seat rail (12), wherein the seat rails (12, 14) mutually encompass each other to form an inner channel (16). In the inner channel (16), a spindle nut (30), which is mounted together with the second seat rail (14), and a spindle (20) that is operatively connected to the spindle nut (30) are arranged. At a front end of the first seat rail (12), a gear unit (50) that can be driven by way of a motor (60) and interacts with the spindle (20) is arranged, wherein the spindle (20) is mounted at a front end section (20a) of the spindle (20) in the gear unit (50), and at a rear end section (20b) of the spindle (20) in a pivot bearing (40) of the first seat rail (12). In the longitudinal direction (x) in front of the spindle nut (30), a first transverse locking bar (100) is accommodated in a slot (12a) of the first seat rail (12), wherein the spindle (20) is guided through an opening (102) of the first transverse bar (100) in a contact-free manner. In the longitudinal direction, at a distance from the first transverse locking bar (100) toward the front, a shoulder (120) of the spindle (20) is arranged, wherein in reaction to a specified action of force, the first transverse locking bar (100) is clamped between the first seat rail (12) and the shoulder (100). As a result, a force from the first seat rail (12) via the first transverse locking bar (100), the shoulder (120), the spindle (20), and the spindle nut (30) can be diverted to the second seat rail (14). The invention further relates to a vehicle seat (1).