Fixed Constant Velocity Universal Joint Asymmetric 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 in rings and small cage offset, leading to reduced torque load capacity and increased risk of cage damage at high angles.
Innovation Solution
The design features a fixed constant velocity universal joint with a pitch angle less than 60 degrees for balls in long pockets and greater than 60 degrees for others, shorter inter-pitch distances, and increased cage offset to match track groove offsets, along with long and short pockets to enhance cage rigidity and mounting operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large balls are used to increase torque load capacity, then torque load capacity is improved, but cage rigidity deteriorates due to narrow columns between pockets
Solution Approach 1:
The patent introduces non-uniform pocket distribution with different circumferential spacings, creating varied column lengths between pockets. This dimensional variation in pocket spacing allows optimization of both ball size for torque capacity and column length for cage rigidity, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent applies different pocket spacing configurations to different locations around the cage circumference. By creating local variations in column lengths between pockets, the design allows certain areas to have enhanced rigidity while maintaining overall torque capacity, rather than requiring uniform design throughout.
2Device complexity
If track offset amounts in rings are large and cage offset is small, then conventional design is maintained, but high angle strength and durability decrease
Solution Approach 1:
The patent modifies the offset parameters of the cage, specifically increasing the cage offset to be substantially equal to the track groove offsets. This parameter change directly addresses the high angle strength and durability issues without requiring complete redesign of the entire joint system.
Solution Approach 2:
The patent applies the principle of partial action by selectively adjusting only the cage offset parameter while maintaining other conventional design features. This targeted modification provides the necessary improvement in high angle performance without the complexity of comprehensive redesign.
3Device complexity
If six balls are disposed at 60 degree pitch, then conventional configuration is maintained, but inter-pitch distance is large reducing compactness
Solution Approach 1:
The patent replaces the symmetric 60-degree pitch arrangement with an asymmetric distribution of balls at different pitch angles (45, 60, and 90 degrees). This asymmetric configuration reduces the overall pitch circle diameter and improves compactness while maintaining functional performance.
4Reliability
If cage offset is increased to match track groove offsets, then high angle durability is improved, but mounting operability may be affected
Solution Approach 1:
The patent incorporates preliminary action by providing guide surfaces and chamfers on the cage and outer ring that facilitate proper alignment and insertion during mounting. These pre-designed features ensure that even with increased cage offset, the assembly can be mounted easily without requiring complex alignment procedures.
Data Source
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AI summary
The present invention provides a fixed constant velocity universal joint that can be 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 can improve high angle strength and durability through lessening instances in which a ball runs over a track at a high angle. A cage 28 includes four pockets 29, a pair of long pockets 30 of which a circumferential direction spacing is wide and a pair of short pockets 31 of which the circumferential direction spacing is narrow. The pair of long pockets 30 are shifted by 180 degrees along a circumferential direction and a pair of short pockets 31 are shifted by 180 degrees along the circumferential direction. The long pockets 30 and the short pockets 31 are alternately disposed along the circumferential direction. A long pocket 30 houses two balls 27. A short pocket 31 houses one ball. An offset amount in the cage is made large to become almost the same as an offset amount of track grooves. Track grooves on a joint inner side are deepened and cage thickness on an opening side is increased.