Fixed Constant-Velocity Universal Joint Cage Design
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Solution Overview
Problem
Conventional fixed constant velocity universal joints face challenges in maintaining high angle strength and durability due to large track offset amounts and shallow track groove depths, leading to increased stress and potential damage from ball interference with track edges, especially at high torque angles.
Innovation Solution
The design incorporates a cage with alternating long and short pockets, projections, and chamfer sections to increase rigidity and prevent interference, allowing for larger balls on a smaller pitch circle diameter without reducing load capacity, and includes an arc section on the inner ring to ensure continuous contact and reduce surface pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large balls are used to increase torque load capacity, then the load capacity is improved, but the cage rigidity deteriorates due to narrow columns between pockets
Solution Approach 1:
The cage is segmented into alternating long pockets and short pockets, creating a structured distribution pattern. This segmentation allows for optimized column spacing - the long pockets provide sufficient column length for rigidity while the short pockets maintain compact overall dimensions, resolving the contradiction between large ball capacity and cage rigidity
Solution Approach 2:
Different regions of the cage are given different qualities through the alternating long and short pockets. The long pockets provide enhanced rigidity in critical areas where columns need greater length, while short pockets are placed where compactness is prioritized, creating local quality variations that simultaneously satisfy both rigidity and size requirements
2Volume of moving object
If the universal joint is made compact with smaller pitch circle diameter, then the size is reduced, but the high angle strength decreases due to shallow track groove depth
Solution Approach 1:
The invention addresses the shallow track groove depth issue by introducing a new dimensional parameter - the offset distance k between the track groove bottom and the pitch circle. This allows the track grooves to be positioned at an optimal depth that maintains high angle strength while keeping the overall pitch circle diameter small, effectively using an additional degree of freedom to resolve the contradiction
3Ease of operation
If track offset amounts are large, then the mounting operability is improved, but the track groove depth becomes shallow leading to ball interference with track edges
Solution Approach 1:
The invention changes the critical parameter of track groove positioning by introducing the offset distance k. By adjusting this parameter, the track grooves are positioned at an optimal location that prevents ball interference with track edges during high-angle operation, while simultaneously maintaining good mounting operability. This parameter optimization resolves the contradiction between ease of mounting and prevention of harmful interference
Data Source
AI summary
A fixed constant velocity universal joint is made compact, has little decrease in load capacity even when the fixed constant velocity universal joint is made compact and is at an operating angle, and has improved high angle strength and durability through lessening instances in which a ball runs over a track at a high angle. In the fixed constant velocity universal joint, a cage includes four pockets, the pockets including a pair of long pockets of which a circumferential direction spacing is wide and a pair of short pockets of which the circumferential direction spacing is narrow. The pair of long pockets are shifted by 180 degrees along a circumferential direction and the pair of short pockets are shifted by 180 degrees along the circumferential direction. As a result, the long pockets and the short pockets are alternately disposed along the circumferential direction. A long pocket houses two balls. A short pocket houses one ball. Two ball housing sections connected by a slit are formed in the long pocket by projections that project towards a long pocket inner side being provided on opposing long sides of the long pocket.