Tripod Joint Roller Element Cage Stop Surfaces
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Solution Overview
Problem
Existing rolling elements and tripod joints face challenges during assembly and transport, as there is a risk of the rolling element being pulled out of the guide, requiring complex assembly processes and increasing production costs.
Innovation Solution
A rolling element with a cage that has stop surfaces to prevent translational movement beyond certain end positions, securing the rolling elements against pull-out by creating a frictional engagement with the outer joint part, allowing existing joint parts to be used without additional processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rolling element is designed without additional securing features, then the structure remains simple and costs are low, but the rolling element can be pulled out during assembly or transport
Solution Approach 1:
The cage is designed to be movable relative to the housing, allowing it to shift position dynamically. This dynamic capability enables the cage to engage with stop surfaces at different positions, providing securing functionality without requiring a complex fixed structure. The movable cage adapts to different operational states while maintaining simplicity.
Solution Approach 2:
The cage acts as an intermediary element between the rolling elements and the housing. It mediates the securing function by interacting with stop surfaces on both the housing and potentially external structures, preventing direct pull-out forces from acting on the rolling elements themselves while maintaining overall structural simplicity.
2Reliability
If a reduction in cross-section is used to prevent pull-out, then the rolling element is secured, but the assembly complexity and production costs increase significantly
Solution Approach 1:
The rolling element is segmented into distinct functional components: the housing, the movable cage, and the rolling elements themselves. This segmentation allows each component to be manufactured independently using standard processes, avoiding the need for complex reduced-cross-section features that would require specialized manufacturing. The cage can be assembled into the housing separately, simplifying production.
Solution Approach 2:
The stop surfaces are implemented as simple geometric features (faces or edges) that can be easily copied during standard manufacturing processes. Rather than requiring complex reduced-cross-section geometries, the stop surfaces are replicated as flat or slightly contoured features on the housing and cage, which are straightforward to manufacture and assemble.
3Volume of moving object
If the rolling element is located inside a sleeve, then the structure is compact, but the assembly effort increases greatly or becomes impossible when the sleeve must be removed
Solution Approach 1:
The movable cage provides self-service securing functionality within the compact structure. The cage automatically engages with the stop surfaces during normal operation, providing pull-out protection without requiring external intervention or complex assembly procedures. The compact design is maintained while the self-service mechanism simplifies assembly by eliminating the need for specialized sleeve removal procedures.
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 effectively prevents the rolling element from being pulled out, simplifying assembly and transport, reducing costs, and maintaining the rolling elements in a desired position without additional mechanical processing of the joint parts.
Implementation Method 1
Rolling bodies (40) are associated with the housing (20) and serve to support the housing (20) on opposing raceways (122) of an outer joint part (120) of the tripod joint (100)
Implementation Method 2
the cage (50) has first stop surfaces (52) and the housing (20) has second stop surfaces (22) associated with them, which are arranged in such a way that a first and a second end position of the cage (50) are fixed relative to the housing (20)
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The element (10) has a housing (20) with a retaining opening that supports a pin (112) of a tripod star (110). Rolling bodies (40) are attached with the housing for supporting the housing on mutually opposite tracks (122) of a joint outer part (120) of a tripod joint (100). The rolling bodies are held by a retainer (50) translationally movable relative to the housing. The housing and the retainer comprise two sets of stop surfaces, which are formed such that end positions of the retainer are defined relative to the housing. The rolling bodies are formed in sphere, cylinder and barrel shapes. An independent claim is also included for a tripod joint.