Tripod CV Joint Roller Structure to Restrain Compelling Force
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Solution Overview
Problem
The existing tripod constant-velocity joints face durability issues due to the generation of compelling forces resulting from changes in joint angles, which can lead to reduced performance and lifespan.
Innovation Solution
The design incorporates a tripod constant-velocity joint with a specific configuration of roller units, including an inner roller, cylindrical rolling elements with crowned ends, and a limiting portion on the outer roller, which defines a clearance that prevents the inner roller from contacting the edge of the rolling elements, thereby restraining compelling forces and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clearance between inner and outer rollers is eliminated due to joint angle change, then the inner roller contacts the radially inward flange portion, but this generates compelling force that reduces durability
Solution Approach 1:
The patent introduces a limiting portion as an intermediary element between the inner roller and the radially inward flange portion. This limiting portion prevents the inner roller from directly contacting the flange portion, thereby eliminating the generation of compelling force while maintaining the necessary structural integrity and durability of the constant-velocity joint
Solution Approach 2:
The patent modifies the clearance parameter between the inner roller and the outer roller by introducing the limiting portion. This changes the spatial relationship and prevents the elimination of clearance that would otherwise occur due to joint angle changes, thereby preventing the generation of harmful compelling forces
2Reliability
If the inner roller contacts the edge of rolling elements, then stress concentration occurs, but the limiting portion prevents this contact to maintain durability
Solution Approach 1:
The limiting portion serves as a protective intermediary that prevents the inner roller from directly contacting the edge of the rolling elements. This eliminates stress concentration at the rolling element edges while maintaining smooth operation and durability of the constant-velocity joint
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
This configuration effectively prevents the inner roller from contacting the edge of the rolling elements, reducing stress concentration and maintaining high durability even at typical joint angles, such as 6 degrees, while allowing for appropriate clearance settings to prevent premature wear.
Implementation Method 1
a plurality of cylindrical rolling elements each including a crowned end portion in an axial end portion thereof; an outer roller supported by the inner roller through the plurality of cylindrical rolling elements
Implementation Method 2
a limiting portion provided integrally in the outer roller and protruding from the outer roller toward an inner peripheral side of the outer roller, so as to limit movements of the plurality of cylindrical rolling elements and the inner roller
Data Source
AI summary
A tripod constant-velocity joint including: an inner ring; three trunnions protruding from the inner ring; three roller units supported by the trunnions; and an outer ring storing the roller units. Each roller unit includes: an inner roller that is in contact with a convex outer-circumferential surface of the corresponding trunnion at a tangent point; an outer roller supported by the inner roller through rolling elements that are interposed between the inner and outer rollers; and a limiting portion protruding from the outer roller, so as to limit movements of the rolling elements and the inner roller. A clearance between the inner roller and the limiting portion is smaller than an axial length of a crowned end portion of each rolling element, and is larger than a stroke distance of reciprocating movement of the tangent point when a joint angle of the tripod constant-velocity joint is a predetermined value.