Steering Column Radial Wedge Assembly for Tube Housing De-Lash
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Solution Overview
Problem
Steering column assemblies with tilt and telescoping functions experience lash due to dimensional tolerance differences, leading to side-to-side motion during adjustment, and existing solutions require many components and adjustments.
Innovation Solution
A simple wedge assembly with a wedge body and pre-load member is used to reduce lash between the column tube and housing, featuring a curved contact face, securing features, and a pre-load member to maintain stiffness and reduce slide force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grub screw acting directly on a spring is used to pre-load a wear-resistant member against the column tube, then lash between column tube and housing is reduced, but the number of components increases and additional adjustments are required
Solution Approach 1:
The wedge assembly merges the grub screw, spring, and wear-resistant member into a single integrated component. The wedge body includes an integrated spring mechanism that provides pre-load without requiring separate adjustment mechanisms, thereby reducing component count while maintaining lash reduction functionality.
Solution Approach 2:
The wedge assembly is designed to be self-adjusting through the spring mechanism that automatically maintains pre-load on the wear-resistant member. The spring compensates for wear and tolerance variations without requiring manual adjustment, eliminating the need for additional adjustments while maintaining reliable lash reduction.
2Ease of manufacture
If dimensional tolerance differences are present between column housing and column tube, then manufacturing is simplified, but lash effect increases causing side to side motion
Solution Approach 1:
The wedge assembly changes the contact geometry between the column tube and housing by introducing a wedge-shaped pre-loaded member. This transforms the interaction from direct surface contact subject to tolerance accumulation to controlled point/line contact through the wedge, which compensates for dimensional variations and eliminates lash while maintaining ease of manufacture.
3Device complexity
If a simple wedge assembly is used, then component complexity is reduced and assembly is simplified, but maintaining stiffness and low slide force becomes challenging
Solution Approach 1:
The wedge assembly utilizes a composite structure combining a rigid wedge body with an integrated spring mechanism. This composite design provides both the stiffness needed to eliminate lash and the compliance needed to maintain low slide force, achieving both goals simultaneously while keeping component complexity low.
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 wedge assembly simplifies assembly, reduces component complexity, and maintains low slide force while eliminating the need for adjustments, providing improved stiffness and reducing lash.
Implementation Method 1
The pre-load member may be, for example, a spring
Implementation Method 2
The wedge body may have a pair of generally opposing long edges and a pair of generally opposing shorter edges. One of the edges (e.g., a long edge) may be a thick edge, and the opposing edge (e.g., the opposing long edge) may be a thin edge. The thickness of the wedge body may decrease from the thick edge to the thin edge.
Data Source
AI summary
A wedge assembly for a steering column assembly including a wedge body and a pre-load member. The wedge body has a generally curved column tube contact face for contacting an outer surface of a column tube and a column housing contact face configured to contact a column housing. The wedge assembly has a thick edge and a thin edge, and the thickness of the wedge body decreases from the thick edge to the thin edge. The pre-load member has an elongated body between a first and a second end. The first end and the second end are secured to and/or positioned within the wedge body. A steering column assembly including the wedge assembly, a column tube, and column housing is also contemplated.