Telescopic Steering Shaft Pull-Out Stop With Angled Forming
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Solution Overview
Problem
Existing steering shaft designs for motor vehicles require complex and costly caulking processes, leading to potential deformation and increased forces needed for displacement, which complicates the production of a simple pull-out safeguard.
Innovation Solution
The design incorporates an inner shaft with axial stops that project radially and interact with axially oriented outer stops on the outer shaft, introduced through forming processes at angles greater than 20° but less than 80° relative to the radial direction, reducing the radial component of the forming force and minimizing deformation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If caulking is introduced into the front face of the outer shaft part to create a pull-out safeguard, then the inner shaft part is prevented from being pulled out, but the production process becomes complicated and costly
Solution Approach 1:
The invention extracts the pull-out safeguard function from the complex caulking process and implements it through simple axial stops on the inner shaft part that engage with corresponding features in the outer shaft part. This separates the retention function from the complicated caulking operation, achieving pull-out prevention through a simpler structural means.
Solution Approach 2:
Instead of creating a pull-out safeguard by modifying the outer shaft part through caulking, the invention inverts the approach by providing axial stops on the inner shaft part that actively engage with the outer shaft part. This reverses which component carries the safeguard features, simplifying the overall production process.
2Manufacturing precision
If the outer shaft part is acted upon directly by a forming tool in the radial direction to introduce outer stops, then the outer stops are properly formed, but the outer shaft part becomes deformed and jammed on the inner shaft part
Solution Approach 1:
The invention applies local quality by introducing outer stops at specific locations on the outer shaft part through forming processes that act locally rather than applying radial force to the entire shaft. This localized approach forms the necessary stops without causing global deformation of the outer shaft part.
Solution Approach 2:
The invention changes the parameters of the forming process by controlling the angle of the forming tool's direction of introduction to be more than 20° relative to the radial direction. This parameter change ensures proper outer stop formation while minimizing radial deformation forces that would cause the outer shaft part to become jammed.
3Shape
If the angle of the forming tool's direction of introduction is increased to reduce radial deformation, then the outer shaft part deformation is minimized, but the forming process becomes more complex
Solution Approach 1:
The invention optimizes the angle parameter of the forming tool's direction of introduction to be more than 20° relative to the radial direction. This specific parameter range achieves the best balance between minimizing radial deformation and maintaining forming process simplicity, avoiding both excessive deformation and unnecessary process complexity.
Data Source
AI summary
A steering shaft having an outer shaft and an inner shaft accommodated therein in a torque-locking, axially displaceable manner and an axial inner stop which projects radially outwards from an outer face of the inner shaft. When the inner shaft is pulled out of the outer shaft, the axial inner stop strikes against an axial outer stop projecting radially inwards from an inner face of the outer shaft, wherein the axial displacement of the inner shaft is limited in the pull-out direction. With regard to simple production of the outer stops with the least possible deformation of the entire cross section of the outer shaft, the outer stop is introduced by at least one forming process into an end portion of the outer shaft, wherein the axis of the direction of introduction in each case forms an angle of more than 20° with the radial direction of the outer shaft.