Vehicle Seat Longitudinal Adjuster Housing for Crash Load Support
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Solution Overview
Problem
Existing longitudinal adjusters for vehicle seats lack sufficient rigidity and load-bearing capacity, and do not effectively absorb and distribute crash loads to ensure safety and durability.
Innovation Solution
A longitudinal adjuster design featuring a gear mechanism housing with a step that supports the worm gear in the event of a crash, providing additional axial support and load distribution through a radially inward protruding step within the gear mechanism housing, which enhances the gear mechanism's ability to absorb and direct crash loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional gear mechanism housing is used without additional support structures, then the device complexity is low, but the load-bearing capacity and rigidity are insufficient
Solution Approach 1:
The gear mechanism housing is segmented into multiple functional regions: the cylindrical bearing portion for normal operation and the radially inward protruding step for crash load support. This segmentation allows the housing to handle different load conditions through distinct structural features, improving load-bearing capacity without requiring a completely redesigned housing structure.
Solution Approach 2:
The solution adds a radial dimension to the housing structure by incorporating a radially inward protruding step. This dimensional addition creates an extra support face for the worm gear, enabling the housing to absorb and distribute crash loads in the axial direction without significantly increasing overall device complexity.
2Reliability
If the worm gear is supported only by cylindrical bearing portions, then the manufacturing is simple, but the crash absorption capability is insufficient
Solution Approach 1:
The radially inward protruding step is pre-formed as an integral part of the housing during manufacturing. This preliminary structural feature is already in place before any crash event occurs, providing immediate crash absorption capability without requiring additional components or post-assembly modifications.
Solution Approach 2:
The crash absorption function is merged into the existing housing structure by forming the radially inward protruding step as an integrated feature. This combines the housing's structural support function with the crash absorption function, eliminating the need for separate crash absorption components and maintaining manufacturing simplicity.
3Stability of the object's composition
If additional support structures are added to the housing, then the rigidity increases, but the device complexity increases
Solution Approach 1:
The additional support structure (radially inward protruding step) is localized to the specific region where crash loads are most critical - the worm gear support area. This local reinforcement provides the necessary rigidity improvement without requiring global structural changes throughout the entire housing, thereby limiting the increase in device complexity.
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 significantly increases the gear mechanism's load-bearing capacity and crash absorption capabilities, ensuring improved rigidity and safety for the vehicle seat by providing additional support faces for the worm gear during impact events.
Implementation Method 1
a worm gear (50a) which is connected to the spindle (20) is supported in the gear mechanism housing (52)
Implementation Method 2
a spindle nut (30) which is supported with the second rail (14) and a spindle (20) which is operationally connected to the spindle nut (30) are arranged in the inner channel (16)
Data Source
AI summary
A longitudinal adjuster for a vehicle seat may have a first rail and a second rail. The rails may mutually engage around each other to form an inner channel. A spindle nut may be supported by the second rail and a spindle, operationally connected to the spindle nut, may be arranged in the inner channel. In one end region of the first rail, a screw drive driven by a motor and interacting with the spindle may be arranged. The screw drive may be enclosed by a housing. The housing may have at least one cylindrical bearing portion for bearing a worm wheel connected to the spindle. The housing may also at least one step adjoining the cylindrical bearing portion. The step may be designed to support the worm wheel in the event of a crash. A vehicle seat having the longitudinal adjuster is also provided.