Steering Column Clamp Mechanism for Crash Force Resistance
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Solution Overview
Problem
Existing steering column assemblies face challenges in preventing unwanted movement during crashes, particularly under high forces, due to reliance on frictional locking mechanisms which can lead to tooth-on-tooth impacts and damage, and fail to maintain the steering wheel's position effectively when forces exceed 5000 N.
Innovation Solution
A steering column assembly with a clamp mechanism featuring interleaved plates and a cam mechanism that provides high static friction through compression of multiple plates, allowing for both reach and rake adjustments while ensuring the shroud is securely fixed to the support bracket, thereby preventing relative movement during crashes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a frictional clamping system is used to secure the shroud to the support bracket, then the clamp mechanism can be simple and allow easy adjustment, but it fails to prevent substantial movement when forces exceed 5000 N
Solution Approach 1:
The clamping interface is segmented into multiple discrete friction surfaces through the use of interleaved plates. Instead of a single friction interface between the shroud and support bracket, the system divides the clamping force across multiple plate interfaces, each contributing to the total frictional resistance. This segmentation allows the system to achieve high force resistance while maintaining adjustment capability through the lever mechanism.
Solution Approach 2:
The interleaved plates act as intermediary elements between the shroud and support bracket. These plates create multiple friction interfaces that mediate the force transfer, providing enhanced resistance to crash forces while still allowing controlled movement during adjustment. The plates serve as a friction-based intermediary that replaces direct rigid contact, enabling both security and adjustability.
2Force
If a tooth-based positive locking assembly is used to provide locking at set positions, then the clamp mechanism can resist high forces, but tooth-on-tooth impacts can occur during damping causing permanent damage to the teeth
Solution Approach 1:
The system converts the potentially harmful impact forces that would damage tooth-based locking into beneficial frictional forces through the interleaved plates. Instead of rigid tooth-on-tooth engagement that causes impact damage, the flexible friction-based plate system absorbs and distributes forces smoothly, transforming the harmful impact mechanism into a beneficial friction-based force distribution mechanism.
Solution Approach 2:
The system changes the fundamental parameter of the locking mechanism from rigid mechanical engagement (tooth-based) to flexible friction-based engagement (interleaved plates). This parameter change from discrete positive locking to continuous friction locking eliminates the impact damage issue while maintaining high force resistance capability through the cumulative effect of multiple friction interfaces.
3Force
If multiple interleaved plates are compressed to provide high static friction, then the steering column remains stable under high forces, but the device complexity increases
Solution Approach 1:
The interleaved plate assembly serves multiple functions simultaneously: it provides the clamping force, creates multiple friction interfaces for high force resistance, enables adjustment through the lever mechanism, and distributes loads across multiple surfaces. This multi-functionality reduces the need for separate components for each function, thereby managing complexity despite the presence of multiple plates.
Solution Approach 2:
The system merges the clamping function, friction interface, and adjustment mechanism into a single integrated clamp assembly. The interleaved plates are combined with the lever-operated cam mechanism, creating a unified system where the same components that provide high frictional force also enable easy adjustment, rather than requiring separate systems for locking and adjusting.
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 achieves a high level of frictional locking force, ensuring the steering column remains stable under high forces, preventing unwanted movement and damage, while allowing for easy adjustment without causing tooth-on-tooth impacts, thus enhancing safety and usability.
Implementation Method 1
The clamp mechanism is configured such that, in the clamped position of the clamp mechanism, the interleaved plates are compressed between the cam mechanism and the shroud to restrict relative movement of the shroud and support bracket
Data Source
AI summary
A steering column assembly includes a shroud; a steering shaft, which is supported by the shroud; a support bracket, a clamp, and a clamp mechanism. The support bracket is configured to be secured to a fixed part of the vehicle and includes two arms that depend from a base portion to embrace the shroud. The clamp pin extends through an opening in each of the arms of the support bracket and in a slot in the shroud. The clamp mechanism is movable between an unclamped position in which the shroud can move relative to the support bracket and a clamped position in which the shroud is fixed relative to the support bracket.