Tripod CV Joint Track Geometry to Prevent Roller Jamming
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Solution Overview
Problem
Existing constant velocity joints face challenges with high friction between parts and a risk of roller jamming, especially at articulated angles, which affects their efficiency and reliability.
Innovation Solution
The proposed constant velocity joint features a male element with multiple arms and a female element with symmetrical tracks, where a mechanical transmission unit with an outer roller rolls on the tracks, and bearing surfaces limit rotation, reducing friction and preventing jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional constant velocity joint design is used, then the joint can transmit power between shafts, but high friction occurs between individual parts and roller jamming risk increases at articulated angles
Solution Approach 1:
The patent employs curved cam surfaces with specific radii of curvature (R1, R2) that are larger than the roller radius. These curved surfaces guide the roller along an optimized path, ensuring continuous point contact and preventing jamming while maintaining low friction through proper geometric curvature matching.
Solution Approach 2:
The patent optimizes geometric parameters including cam surface radii (R1, R2), roller radius (r), and pressure angle (α) to achieve ideal rolling conditions. By carefully selecting these parameters, the design ensures that the roller maintains point contact with the cam surfaces throughout the articulation range, minimizing friction and preventing jamming.
2Adaptability or versatility
If the joint operates at articulated angles, then the joint provides motion flexibility, but roller jamming risk increases
Solution Approach 1:
The cam surfaces are designed with specific curved geometries that guide the roller through a controlled path during articulation. The curvature radii R1 and R2 are deliberately chosen to be larger than the roller radius, ensuring that the roller maintains stable point contact even at maximum articulation angles, thereby preventing jamming while enabling full motion flexibility.
Solution Approach 2:
The cam profile is pre-designed to anticipate and prevent roller jamming before it can occur. The geometric configuration of the cam surfaces creates inherent mechanical guidance that keeps the roller centered and prevents it from binding, even under the adverse conditions of high articulated angle operation.
3Ease of manufacture
If conventional joint design is used, then the structure is simple, but manufacturing precision requirements are not optimized for low friction operation
Solution Approach 1:
The patent specifies optimized geometric parameters for the cam surfaces and roller, including radii R1, R2, and r, and pressure angle α. These parameters are carefully selected to achieve ideal rolling contact conditions. By standardizing these parameters, the design balances manufacturing feasibility with the precision needed to minimize friction and ensure reliable operation.
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 design achieves low friction and reduces the risk of roller jamming, resulting in a more efficient, durable, and economical constant velocity joint with minimal shudder during operation.
Implementation Method 1
A mechanical transmission unit (26) comprising an outer roller (28) is mounted on each arm (8) so as to plunge and slide in relation to the arm (8) and which is designed to roll on one or other of the corresponding two tracks (18, 20) via a peripheral rolling surface (52)
Implementation Method 2
the female element (16) furthermore comprising at least one bearing surface (60, 62) which prevents or limits the rotation of the outer roller (28) around an axis perpendicular to the female element central axis (X′-X′) and to the axis of the arm (8)
Data Source
AI summary
A constant velocity joint comprises a male element having arms, a female element having a central axis and defining a pair of symmetrical tracks and an outer roller which can roll on one or other of the two tracks via a peripheral rolling surface. The female element comprises at least one bearing surface which limits the rotation of the outer roller around an axis perpendicular to the axis' of the female element and of the arm. With respect to each arm the cross-section profile of each track comprises either two circular arcs having centers of radii offset one from another, or one single circular arc extending over a female element median plane, and the rolling surface has a part spherical shape or a part torical shape. Each track and the rolling surface are capable of contacting each other at a first and second contact points spaced radially from one another. The tilting of the roller is controlled by proximal and distal rails on the female element and by proximal and distal breaking surfaces on the outer roller.