Steering Column Ball Track Interface for Stiff Low-Effort Telescoping
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Solution Overview
Problem
Conventional steering column designs with 'tube-on-tube' and tele-bushing interfaces face challenges in meeting performance specifications for natural frequency, stiffness, and telescope effort, which are further affected by temperature variations due to differing coefficients of thermal expansion between plastic and steel components.
Innovation Solution
A recirculating ball track telescope interface assembly is introduced, featuring steel components with integrated metal tracks and steel balls, allowing for axial adjustment with low friction and consistent performance across temperature changes, eliminating the need for additional ball retention components and reducing part count and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a tube-on-tube interface with injected tele-bushing is used, then the manufacturing is simplified, but the natural frequency and stiffness performance deteriorates
Solution Approach 1:
The patent changes the material parameters by replacing plastic tele-bushing with steel balls and steel tracks, fundamentally altering the interface characteristics to achieve both manufacturability and high stiffness performance through metal-on-metal contact
2Strength
If high pressure plastic injection is used to improve stiffness, then the stiffness improves, but the telescope effort worsens
Solution Approach 1:
The patent substitutes the plastic deformation mechanism with a rolling ball mechanism, replacing the high-pressure injection molded plastic interface with steel balls rolling on steel tracks, thereby achieving stiffness through metal contact while minimizing friction and telescope effort
3Ease of manufacture
If plastic bushing and steel jackets with differing thermal expansion coefficients are used, then the manufacturing is easier, but the performance consistency across temperatures deteriorates
Solution Approach 1:
The patent applies homogeneity by using steel material for both the jackets and the balls, ensuring uniform thermal expansion characteristics across all interface components, which maintains performance consistency across varying temperature conditions
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 enhances the steering column's natural frequency and stiffness while maintaining low telescope effort, ensuring consistent performance and reducing the need for costly redesigns by using a metal-on-metal interface with similar thermal expansion coefficients.
Implementation Method 1
a plurality of steel balls disposed in the track to provide a rolling interface between the first component and the second component during axial adjustment therebetween
Implementation Method 2
using a metal-on-metal interface with similar thermal expansion coefficients
Data Source
AI summary
An axially adjustable steering column assembly includes a first support structure. The axially adjustable steering column assembly also includes a second support structure, wherein the first support structure is axially adjustable relative to the second support structure in a telescoping manner. The axially adjustable steering column assembly further includes a plurality of telescope interface assemblies disposed between the first support structure and the second support structure. Each of the telescope interface assemblies include a track formed in at least one of the first support structure and the second support structure. Each of the telescope interface assemblies also includes a plurality of metal balls disposed in the track to provide a rolling interface between the first support structure and the second support structure during axial adjustment therebetween.