Constant Velocity Joint Ball Tracks for Cage Control at Varying Angles
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Solution Overview
Problem
Constant velocity joints face challenges in maintaining reliable cage control at small deflection angles and ensuring sufficient torque transmission capacity at larger deflection angles, while minimizing reaction forces and wear for efficient operation.
Innovation Solution
A constant velocity joint design featuring outer and inner ball tracks with specific jaw opening angle characteristics, where the jaw opening angle increases more significantly within a central deflection angle range of up to 20 degrees, and then decreases at larger deflection angles, ensuring reliable ball guidance and minimal axial protrusion, with track pairs designed to have different curvature segments and a ball cage with spherical surfaces for optimal cage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the track curvature is increased to improve cage control at small deflection angles, then the jaw opening angle increases, but torque transmission capacity at larger deflection angles deteriorates
Solution Approach 1:
The ball track is divided into multiple sections with different curvature radii. The first section has a smaller curvature radius to provide adequate jaw opening angle for cage control at small deflection angles, while the second section has a larger curvature radius to maintain torque transmission capacity at larger deflection angles. This segmentation allows each section to optimize for its specific operational range.
Solution Approach 2:
Different sections of the ball track are assigned different local geometric properties (curvature radii). The first section near the median plane has a smaller curvature radius for effective cage control, while the second section at larger deflection angles has a larger curvature radius for sufficient torque capacity. This local differentiation resolves the contradiction between cage control and torque transmission.
2Reliability
If the jaw opening angle is increased to improve ball guidance, then cage control is enhanced, but the reaction forces and wear increase
Solution Approach 1:
The ball track is segmented into sections with different curvature characteristics. The first section provides adequate jaw opening for ball guidance and cage control, while the second section reduces the jaw opening angle to minimize reaction forces and wear at larger deflection angles. This segmentation balances guidance quality with force reduction.
Solution Approach 2:
The curvature radius parameter of the ball track is varied along its length. By changing the curvature radius from smaller in the first section to larger in the second section, the jaw opening angle is optimized for different operational phases, achieving good ball guidance while controlling reaction forces and wear through parameter variation.
3Reliability
If the track design prioritizes small deflection angle performance, then cage control is improved, but large deflection angle torque capacity is reduced
Solution Approach 1:
The ball track is divided into a first section optimized for small deflection angles with smaller curvature radius for cage control, and a second section optimized for large deflection angles with larger curvature radius for torque capacity. This segmentation allows the joint to excel at both small and large angle operations without compromising either performance aspect.
Solution Approach 2:
The ball track geometry is designed to dynamically adapt to different deflection angle ranges. As the joint moves from small to large deflection angles, the ball transitions from the first track section to the second section, automatically adjusting the jaw opening angle to match the operational requirements at each angle range.
Data Source
Figure 1A~1C
Figure 1D~1E
Figure 1F~1G
AI summary
The invention relates to a constant velocity joint, comprising: a joint outer part (12) with outer ball tracks (22), a joint inner part (13) with inner ball tracks (23), wherein in each case one outer ball track (22) and one inner ball track (23) form a track pair (22, 23) with one another; in each case one torque-transmitting ball (14) in each track pair (22, 23); a ball cage (15), in which the torque-transmitting balls (14) are received; wherein a first articulation angle range is defined which comprises articulation angles (ß) of less than twenty degrees, and a second articulation angle range which comprises articulation angles (ß) of greater than twenty degrees; wherein a mouth opening angle (δ) increases within the first articulation angle range with an increasing articulation angle (ß), and wherein a first mean mouth opening angle rise (S1) of the first articulation angle range is greater than a second mean mouth opening angle rise (S2) of the second articulation angle range.