CV Joint Ball Track Geometry for Low Friction Cage Control
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Solution Overview
Problem
Constant velocity joints face challenges in minimizing reaction forces and friction losses while maintaining reliable operation across various angular positions, which affects their efficiency and wear resistance.
Innovation Solution
A constant velocity joint design featuring outer and inner ball tracks with a ball cage that ensures reliable cage control at small articulation angles, characterized by small opening angles between the joint parts, resulting in low reaction forces and reduced friction losses, with the ball tracks configured to increase opening angles gradually with increasing articulation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the ball tracks are configured with small opening angles to minimize reaction forces and friction losses, then efficiency is improved, but reliable cage control at small articulation angles becomes difficult to achieve
Solution Approach 1:
The patent applies parameter changes by configuring the ball tracks with specific geometric parameters - small opening angles (α) between the outer and inner ball track tangents. This parameter optimization minimizes reaction forces and friction losses while maintaining reliable cage control through precise track geometry design that ensures proper ball engagement across all articulation angles
Solution Approach 2:
The patent implements dynamics by designing the ball tracks to adaptively control the opening angle behavior. The outer and inner ball tracks are configured such that the opening angle increases with articulation angle, providing dynamic adjustment of contact geometry. This ensures reliable cage control at small articulation angles while maintaining low friction losses throughout the operating range
2Power
If the opening angle is kept small to reduce reaction forces, then power losses are minimized, but the joint may not maintain reliable operation across all angular positions
Solution Approach 1:
The patent optimizes power losses through parameter changes in the ball track geometry. The opening angle α is carefully selected and maintained small throughout the operating range, with the track profiles designed to achieve this. This parameter optimization minimizes the reaction forces between balls and tracks, thereby reducing power losses while ensuring reliable operation
Solution Approach 2:
The patent achieves dynamic adaptation of the contact geometry through the ball track configuration. As the articulation angle changes, the opening angle between the ball tracks increases accordingly, providing dynamic optimization of the contact conditions. This ensures reliable operation across all angular positions while maintaining minimal power losses throughout the range of motion
Data Source
AI summary
A constant velocity joint comprises an outer joint part with outer ball tracks and an inner joint part with inner ball tracks. An outer ball track and an inner ball track respectively form a pair of tracks with one another; in each, a torque-transmitting ball is guided. The torque-transmitting balls are accommodated in a ball cage with circumferentially distributed cage windows. In any angular position of the constant velocity joint an opening angle is formed between an outer tangent to the outer ball track and an inner tangent to the inner ball track. At an articulation angle of zero degrees the opening angle is greater than zero degrees. A central articulation angle range is defined with articulation angles less than fifteen degrees. The opening angle increases by at least two degrees within the central articulation angle range, and is less than twelve degrees for all articulation angles within the central articulation angle range.