Fixed CV Joint Cage Geometry for Large Operating Angles
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Solution Overview
Problem
Fixed type constant velocity universal joints face challenges in achieving large operating angles without interference and maintaining cage strength, as existing designs either shorten track grooves leading to ball disengagement or increase weight and complexity.
Innovation Solution
The design incorporates track grooves on both the outer and inner joint members with specific phase angles and overlapping projections to manage ball engagement and disengagement, ensuring the ball returns to contact within the track groove, thereby maintaining torque transmission and preventing shear fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the outer joint member length is shortened to prevent interference at large operating angles, then interference is avoided, but track grooves become shorter causing ball disengagement
Solution Approach 1:
The patent introduces a phase angle dimension (φ1, φ2) to characterize ball position within the track groove. By controlling the ball's phase angle at the opening side end portion, the invention ensures proper engagement even with shortened track grooves at large operating angles, resolving the contradiction between compact size and reliable ball engagement.
Solution Approach 2:
The patent changes the geometric parameters of the track groove, specifically setting the phase angle of the ball at the opening side end portion to be 0° ≤ φ < 45°. This parameter control ensures the ball maintains proper contact with the track groove throughout the operating cycle, preventing disengagement while allowing the outer joint member to be shortened for large operating angles.
2Strength
If the cage strength is increased to prevent shear fractures at large operating angles, then structural integrity is improved, but weight and complexity increase
Solution Approach 1:
The patent ensures that the ball returns to contact with the track groove at a controlled phase angle (0° ≤ φ < 45°) before critical shear forces can damage the cage. This preliminary engagement action prevents excessive loads on the cage, allowing the use of lighter cage designs that would otherwise be insufficient for large operating angles.
Solution Approach 2:
The patent converts the potential harmful effect of ball disengagement and cage shear fractures into a beneficial controlled engagement mechanism. By designing the track groove geometry to guide the ball back into contact at the appropriate phase angle, the system transforms what would be damaging intermittent contact into a controlled, protective engagement that reduces stress on the cage structure.
3Adaptability or versatility
If track grooves are shortened to accommodate large operating angles, then interference is prevented, but torque transmission reliability decreases due to ball loss of contact
Solution Approach 1:
The patent controls the phase angle parameter of the ball position within the track groove, maintaining it within 0° ≤ φ < 45° at the opening side end portion. This parameter control ensures continuous torque transmission through proper ball engagement, even with the shortened track grooves necessitated by large operating angles.
Solution Approach 2:
The patent ensures continuous torque transmission by designing the track groove geometry to guide the ball back into contact at the appropriate phase angle. This continuous engagement eliminates gaps in torque transmission that would occur with ball disengagement, maintaining power flow even with shortened track grooves for large operating angles.
Data Source
AI summary
A fixed type constant velocity universal joint has an operation mode in which, when a maximum operating angle is taken, in a column portion that is one of column portions on both sides of a pocket of a cage receiving a torque transmission ball at a phase angle and is located on a side corresponding to a phase angle larger than the phase angle, a projection end portion obtained by projecting an end portion of a spherical inner peripheral surface of the outer joint member on the opening side in a perpendicular direction toward the spherical outer peripheral surface of the cage and a projection end portion obtained by projecting an end portion of the spherical outer peripheral surface of the inner joint member on the back side in the perpendicular direction toward the spherical inner peripheral surface of the cage overlap in the axial direction of the cage.