Rotational Eccentric Locking for Steering Column Impact Absorption
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Solution Overview
Problem
Existing steering column assemblies face challenges in providing adequate damping and efficient force absorption during accidents due to limited axial opening stroke in the 'Head Over Pin' design, which restricts the locking device's effectiveness in absorbing impact forces.
Innovation Solution
A locking device with a rotationally actuated eccentric part that engages with a retaining part, providing frictional locking and adaptive load absorption, allowing for intensified clamping force during increased loads without requiring additional axial space, and is designed to lock both tilt and longitudinal adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the 'Head Over Pin' design is used with limited axial opening stroke, then the activation mechanism is compact, but the locking device cannot provide adequate force absorption during accidents
Solution Approach 1:
The patent transitions from axial movement to rotational movement for activating the locking device. The operating unit rotates the eccentric part about an axis, converting the limited axial opening stroke into effective rotational action that engages the locking portion with the retaining part, thereby providing adequate force absorption without requiring additional axial space.
Solution Approach 2:
The patent changes the activation parameter from linear displacement to rotational angle. By rotating the eccentric part through a specific angle, the locking portion is brought into engagement with the retaining part, creating a frictional locking effect that can absorb impact forces. This parameter change allows the system to achieve force absorption capability within the constraints of the limited axial opening stroke.
2Reliability
If a positive locking mechanism is used, then the locking device provides secure locking, but it prevents further movement that would intensify clamping force during accidents
Solution Approach 1:
The patent employs a dynamic frictional locking mechanism instead of a static positive locking. The eccentric part can rotate further in the event of an accident, causing the locking portion to press more firmly against the retaining part and intensify the clamping force. This dynamic capability allows the system to adapt to increasing loads while maintaining reliable locking through friction.
Solution Approach 2:
The locking device automatically intensifies its clamping force in response to accident forces without requiring additional activation. The further rotation of the eccentric part during impact causes the locking portion to engage more deeply with the retaining part, creating a self-reinforcing effect that increases force absorption capability as loads increase.
3Length of stationary object
If the eccentric part is rotationally actuated, then no additional axial space is required, but the mechanism becomes more complex
Solution Approach 1:
The eccentric part serves multiple functions: it acts as both the operating element that is rotated by the operating unit and the locking element that engages with the retaining part. The same rotational movement that activates the mechanism also creates the frictional locking effect, eliminating the need for separate activation and locking components and thereby reducing overall mechanism complexity despite the rotational actuation.
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 ensures effective force transmission and enhanced damping capabilities during accidents, allowing the steering column assembly to maintain stability and control by intensifying the clamping force in response to higher loads, thus improving safety and handling.
Implementation Method 1
The locking portion and the engaging portion together do not form a positive locking, but only a frictional locking
Implementation Method 2
The locking devices used can also be utilized to at least partially absorb the forces occurring in an impact, collision, or accident
Data Source
AI summary
A locking device for an adjustable steering column assembly of a motor vehicle is described, comprising an operating unit which has at least one closed and one open position, a control element coupled to the operating unit, and at least one eccentric part which is actuated by the control element. A retaining part is provided, which interacts with the eccentric part in the closed position, wherein a locking portion of the eccentric part engages on an engaging portion of the retaining part in the closed position. The eccentric part has a force transmission portion which is substantially opposite to the locking portion, wherein the force transmission portion in the closed position rests against a support surface lying substantially opposite to the engaging portion. Furthermore, a steering column assembly is described.