Steering Column Preload Mechanism for Limited Overlap Stiffness
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Solution Overview
Problem
Packaging constraints often limit the available overlap between telescopic parts of steering column assemblies, challenging the provision of adequate natural frequency performance and stiffness.
Innovation Solution
A preload mechanism is introduced between telescopic column tubes, actuated at a predetermined position to provide a biasing force perpendicular to the adjustment axis, increasing stiffness, especially in extended positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the overlap between telescopic parts is increased to improve stiffness and natural frequency performance, then the natural frequency performance is improved, but packaging constraints are violated
Solution Approach 1:
The preload mechanism applies a biasing force in advance to the second column tube, creating preliminary compression that increases stiffness before the tube reaches its extended position. This allows the system to achieve high stiffness performance without requiring excessive overlap between telescopic parts, as the stiffness is enhanced by the pre-applied force rather than solely by structural overlap.
2Reliability
If the overlap between telescopic parts is increased to improve natural frequency performance, then the natural frequency performance is improved, but packaging constraints are violated
Solution Approach 1:
The preload mechanism activates at a predetermined position to apply a biasing force that enhances natural frequency performance. By introducing this preliminary action, the system achieves improved reliability in terms of vibration characteristics without requiring increased overlap volume, as the dynamic performance is enhanced by the pre-applied mechanical force rather than structural mass.
3Strength
If a preload mechanism is added to provide biasing force and increase stiffness, then stiffness is improved, but device complexity increases
Solution Approach 1:
The preload mechanism is designed to be self-actuating through the relative movement between the first and second column tubes. As the second column tube moves along the adjustment axis, it automatically triggers the preload mechanism at a predetermined position, eliminating the need for external actuators, sensors, or control systems. This self-service approach provides the necessary stiffness enhancement while minimizing 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
Enhances the natural frequency performance and stiffness of the steering column assembly by providing additional support when overlap is limited, improving comfort and functionality.
Implementation Method 1
A preload mechanism is introduced between telescopic column tubes, actuated at a predetermined position to provide a biasing force perpendicular to the adjustment axis, increasing stiffness
Data Source
AI summary
A steering column assembly (10) for a vehicle has a first end (10a) for connection with a steering wheel and a second end (10b) spaced along an adjustment axis (A-A) from the first end (10a). The assembly (10) comprises a first column tube (20) and a second column tube (40) telescopically received within the first column tube (20) and displaceable with respect to the first column tube (20) along the adjustment axis (A-A). A preload mechanism (60) is located between the first column tube (20) and the second column tube (40). The preload mechanism (60) is configured to be actuated at a predetermined position of the second column tube (40) with respect to the first column tube (20).