Telescopic Drive Joint Deformation for Axial Disengagement
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Solution Overview
Problem
Existing telescoping drive joints in motor vehicles are prone to uncontrolled bending during accidents due to high axial forces, which can lead to injury, and are complex and costly to produce and assemble, as they rely on a burst cage mechanism that may not always allow reliable axial shortening without wedging issues.
Innovation Solution
A drive joint design that disengages by elastic or plastic deformation of joint parts when a predetermined axial force is exceeded, allowing the inner shaft section to telescope into the outer without damaging components, using a configuration with slanted raceways and a spherical cage for centered mounting, enabling controlled disengagement similar to a push-button mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a burst cage mechanism is used to enable telescoping during accidents, then axial shortening is achieved, but the cage may become wedged or fail to destroy reliably, leading to uncontrolled shaft bending
Solution Approach 1:
The invention extracts the fragile cage component from the telescoping mechanism and replaces it with a robust deformation element integrated into the outer joint hub. This eliminates the burst cage while maintaining the telescoping function through controlled deformation of the outer joint hub itself, which absorbs the accident energy and enables reliable axial shortening without the risk of wedging or failure.
Solution Approach 2:
The invention changes the physical state and properties of the outer joint hub by designing it as a deformation element with specific material properties and geometric features. The outer joint hub is configured to undergo controlled plastic deformation when axial force exceeds a predetermined threshold, transforming the rigid connection into a telescoping mechanism without requiring a separate burst device.
2Ease of operation
If the cage is designed to burst under high axial force, then telescoping is initiated, but the high force requirement may cause uncontrolled bending instead of telescoping
Solution Approach 1:
The invention prepares the outer joint hub in advance as a deformation element with predetermined deformation characteristics. The hub is designed with geometric features and material properties that enable it to deform at a controlled, lower force threshold, initiating telescoping before uncontrolled bending can occur. This preliminary configuration ensures that the telescoping mechanism activates at the appropriate moment during an accident.
3Productivity
If a complex burst cage mechanism is used, then telescoping function is achieved, but production and assembly costs increase
Solution Approach 1:
The invention merges the function of the separate cage component into the outer joint hub itself by designing the hub as a deformation element. This integration eliminates the need for a separate cage part, reducing the number of components from two (cage + outer hub) to one (integrated outer joint hub), thereby simplifying production, assembly, and reducing manufacturing costs while maintaining the telescoping function.
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
Ensures reliable and bend-free telescoping, preventing uncontrolled shaft bending and injury, while simplifying production and assembly by allowing deformation of joint parts to facilitate disengagement without component destruction, thus enhancing safety and reducing manufacturing costs.
Implementation Method 1
Disengagement can take place by means of elastic and/or plastic deformation of individual ones or several of the joint parts
Implementation Method 2
Disengagement can take place by means of elastic and/or plastic deformation of individual ones or several of the joint parts
Data Source
AI summary
The invention relates to a drive joint for permitting a rotationally and axially fixed connection between a first and second shaft sub-section, the connection allowing a limited angular displacement.