Multi-Level Knee Bolster Force Load Limiter
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Solution Overview
Problem
Conventional knee bolster systems in vehicles are inadequate in absorbing impact forces during collisions, leading to potential serious injuries to occupants, as they fail to effectively limit the intrusion of the occupant's knee.
Innovation Solution
A multi-level force load limiter system comprising a first, second, and third force limiter, where the first limiter uses a rotational arm with a contact plate, the second limiter employs a torsionally deflecting rod, and the third limiter includes a locking gear and female locking base to progressively absorb and resist impact forces across three stages, preventing further rotation after a predetermined angle is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple shock absorbing plate is used in the conventional knee bolster system, then the device complexity is low, but the impact force absorption capability is insufficient
Solution Approach 1:
The knee bolster system is divided into three distinct force load limiters (first, second, and third), each responsible for absorbing impact forces at different stages. This segmentation allows the system to handle progressive impact forces more effectively while maintaining manageable complexity through modular design
Solution Approach 2:
The three force load limiters are arranged in a nested configuration where the first force load limiter is positioned within the second, and the second within the third. This nesting allows progressive engagement of limiters as impact force increases, improving force absorption capability without proportionally increasing overall device complexity
2Stability of the object's composition
If a knee bolster system with controlled deflection is used, then the deflection control capability is improved, but the knee intrusion limitation is insufficient during collision
Solution Approach 1:
Each force load limiter is designed with specific geometric parameters (rod dimensions, arm lengths, locking angles) that change progressively through the three stages. The parameters are optimized to provide increasing resistance to knee intrusion while maintaining controlled deflection, addressing both deflection control and intrusion limitation requirements
3Loss of energy
If a multi-level force load limiter with three stages is implemented, then the impact energy absorption capability is improved, but the device complexity increases
Solution Approach 1:
The force load limiters incorporate dynamic elements including rotational arms that pivot, rods that deflect torsionally, and locking mechanisms that engage at predetermined angles. These dynamic components allow the system to adapt its stiffness and force absorption characteristics progressively through three stages, improving energy absorption while using motion-based mechanisms rather than purely static structures
Solution Approach 2:
The locking gear and female locking base automatically engage when the rotational arm rotates to a predetermined angle, providing self-locking functionality without requiring external control systems. This self-service mechanism reduces the need for additional control components, partially offsetting the complexity increase from having three stages
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 system effectively absorbs and distributes impact energy across multiple stages, providing enhanced protection to vehicle occupants by resisting and limiting knee intrusion forces, thus reducing the risk of injury during collisions.
Implementation Method 1
The first rod is configured to deflect torsionally by allowing relative rotation
Data Source
AI summary
A knee bolster system for absorbing an impact energy of an occupant's knee is provided with a multi-level force load limiter. The multi-level force load limiter includes three force load limiters. A first force load limiter includes a contact plate for receiving an impact force by the occupant's knee during a vehicle collision. A second force load limiter includes a torsional deflection rod for deforming torsionally by allowing relative rotation, and a third force load limiter includes a locking gear and a female locking base for locking further rotation of a rotational arm after rotation of the torsional deflection rod in the second force load limiter by a predetermined angle based on rotation of the rotational arm. Accordingly, the multi-level force load limiter can create a higher torsion force on the rotational arm of the knee bolster system.