Fixed CV Joint Track Geometry for Stable Torque at Large Angles
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Solution Overview
Problem
The six-ball track crossing type constant velocity universal joint experiences instability and increased torque loss due to cage rotation caused by uneven wedge angles, leading to abnormal heat generation, especially at larger operating angles.
Innovation Solution
The track grooves of the outer and inner joint members are inclined in opposite directions with different inclination angles, increasing the spherical surface width and pillar length of the cage, allowing for angular contact between balls and grooves, and offsetting the track center to vary groove depths, thereby enhancing stability and reducing sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the track grooves of the outer and inner joint members are inclined in opposite directions with different inclination angles, then the spherical surface width and pillar length of the cage are increased, but the structure becomes more complex
Solution Approach 1:
The track grooves of the outer joint member and inner joint member are inclined in opposite directions with different inclination angles (α1 and α2), creating an asymmetric configuration. This asymmetric design increases the spherical surface width and pillar length of the cage, thereby enhancing structural strength while maintaining operational stability across a wider range of operating angles.
2Strength
If the inclination angles of the torque transmitting ball tracks adjacent to each other in the circumferential direction are set to be different, then the cage strength is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
Different inclination angles (α1 for odd-numbered tracks, α2 for even-numbered tracks) are applied to different ball tracks around the circumferential direction. This local differentiation enhances cage strength by increasing pillar lengths while distributing stress more evenly. The design allows for practical manufacturing by specifying reasonable angle ranges rather than requiring identical precision for all tracks.
3Reliability
If the track center is offset to vary groove depths, then ball drop-off is prevented, but the manufacturing complexity increases
Solution Approach 1:
The track center is offset from the spherical surface center by a predetermined amount, creating different groove depths in advance. This preliminary offset ensures that balls are properly retained within the grooves during operation, preventing ball drop-off. The offset amount is carefully selected to provide sufficient retention while remaining feasible for manufacturing.
Data Source
Figure 1
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AI summary
In a fixed type constant velocity universal joint according to the present invention, six torque transmitting ball tracks (20) are defined as a first track, a second track, a third track, a fourth track, a fifth track, and a sixth track along a circumferential direction. Further, in the fixed type constant velocity universal joint according to the present invention, an axial offset amount of a curvature center of each of track grooves (12) of an outer joint member (13) and an axial offset amount of a curvature center of each of track grooves (15) of an inner joint member (16) are set to 0. Further, in the fixed type constant velocity universal joint according to the present invention, the track grooves (12) of the outer joint member (13) and the track grooves (15) of the inner joint member (16) are each inclined with respect to an axis line.