Double-Offset Plunging CV Joint Structure for Large Operating Angles
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Solution Overview
Problem
The existing plunging type constant velocity universal joints cannot achieve a maximum operating angle of 40°, which is within the range of the fixed type constant velocity universal joint, limiting their application in vehicles with larger suspension angles and varying drive system layouts.
Innovation Solution
A plunging type constant velocity universal joint with organically associated internal specifications, including a specific ratio of ball diameter to cage thickness, ball diameter to spline diameter, and ball contact ratio, allowing for a maximum operating angle of 39° or more, achieved through a configuration with offset curvature centers and gothic arch-shaped track grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plunging type constant velocity universal joint is designed with conventional internal specifications, then it can be manufactured with standard dimensions, but the maximum operating angle is limited to 23°-30° and cannot reach 40°
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between internal dimensions: the ratio of ball diameter to cage thickness (0.45-0.55), ball diameter to spline large diameter (0.75-0.85), and cage outer diameter to ball diameter (1.85-2.15). These parameter optimizations enable the joint to achieve a maximum operating angle of 39° or more while maintaining manufacturability and structural integrity.
2Adaptability or versatility
If the maximum operating angle is increased to 40°, then the joint can accommodate larger suspension angles and varying drive system layouts, but the joint load capacity and strength of cage pillar portions deteriorate
Solution Approach 1:
The patent resolves this contradiction by optimizing the ratio of ball diameter to cage thickness within 0.45-0.55 and cage outer diameter to ball diameter within 1.85-2.15. These parameter relationships ensure that the cage pillar portions maintain sufficient strength and the joint can handle full bound and full rebound states even at 39° or greater operating angles.
Solution Approach 2:
The patent employs composite structural design by combining the cage structure with properly sized torque transmission balls, where the dimensional relationships between components create a composite system that distributes loads effectively, maintaining strength at large operating angles.
3Adaptability or versatility
If a six-ball type DOJ is used to achieve large operating angle (25°-32°), then the joint load capacity is secured, but the outer diameter of outer joint member increases by 4%-6%
Solution Approach 1:
The patent optimizes the ratio of cage outer diameter to ball diameter within 1.85-2.15 and ball diameter to spline large diameter within 0.75-0.85. These parameter relationships enable achieving a maximum operating angle of 39° or more while preventing excessive increase in outer joint member outer diameter, thus avoiding the 4%-6% size penalty of conventional designs.
Data Source
AI summary
A double-offset plunging type constant velocity universal joint includes inner and outer joint members each having six linear track grooves extending along an axial direction. The inner joint member has a coupling hole at a center portion thereof for coupling a shaft. Six torque transmission balls retained by a cage are incorporated between the linear track grooves of the inner and outer joint members. A ratio TCAGE/DBALL of a minimum thickness (TCAGE) of the cage to a diameter of the torque transmission ball (DBALL) is from 0.225 to 0.245, wherein a ratio DBALL/DS of a diameter (DBALL) of the torque transmission ball to a spline large diameter (DS) of the coupling hole of the inner joint member is from 0.79 to 0.85, and wherein a ball contact ratio (ψ) of the torque transmission ball is from 1.08 to 1.12.