Slide-Type Constant Velocity Universal Joint High Operating Angle
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Solution Overview
Problem
Conventional slide-type constant velocity universal joints with six torque transmission balls face challenges in achieving high operating angles while maintaining size and weight reduction, as increasing the operating angle beyond 25° results in significant weight gain due to increased outer ring diameters.
Innovation Solution
A slide-type constant velocity universal joint design with a ball contact angle of 30° to 35°, a ball groove contact ratio of 1.02 to 1.08, and a cage offset amount of 0.07 to 0.09, allowing for a maximum operating angle of 30° or more while reducing the outer ring diameter, thereby achieving a lighter and more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer ring diameter is increased to achieve high operating angle (25° or more), then the joint load capacity is improved, but the weight and size of the universal joint increase significantly
Solution Approach 1:
The patent applies parameter changes by optimizing the ball contact angle (30°-35°), ball groove contact ratio (1.02-1.08), and cage offset amount (0.07-0.09 times ball pitch diameter). These parameter optimizations enable the ball to maintain proper contact with ball grooves at high operating angles without requiring increased outer ring diameter, thus achieving high load capacity while reducing weight and size.
2Strength
If the outer ring diameter is increased to achieve high operating angle (25° or more), then the joint load capacity is improved, but the size of the universal joint increases
Solution Approach 1:
The patent optimizes critical parameters including ball contact angle (30°-35°), ball groove contact ratio (1.02-1.08), and cage offset amount. These parameter changes enable the universal joint to achieve high operating angles (30° or more) and high load capacity without increasing outer ring diameter, thereby reducing overall joint size while maintaining structural strength.
3Weight of moving object
If the ball diameter and ball pitch diameter are decreased to make the joint compact and light-weight, then the size and weight are reduced, but the contact ellipse between ball and ball groove may run off and contact stress increases
Solution Approach 1:
The patent optimizes the ball groove contact ratio to 1.02-1.08, ensuring that the contact ellipse remains properly positioned within the ball groove even when ball diameter and pitch diameter are reduced. This contact ratio optimization prevents the contact ellipse from running off the groove edge, maintaining reliable torque transmission and preventing excessive contact stress despite compact dimensions.
Solution Approach 2:
The patent utilizes spherical geometry in the ball and ball groove design, with optimized curvature radii and contact angles. The spherical contact surfaces ensure proper distribution of contact stress and maintain the contact ellipse within the groove boundaries, enhancing reliability while allowing reduced ball dimensions for compactness.
Data Source
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AI summary
The present invention provides a light and compact slide-type constant velocity universal joint that can have a maximum operating angle of 30° or more through optimization of a ball contact angle relative to ball grooves, a ball contact ratio, and a cage offset amount. The present invention is the slide-type constant velocity universal joint including an outer ring 12 in which six linear ball grooves 12b are formed on a cylindrical inner circumferential surface 12a in an axial direction, an inner ring 13 on which six linear ball grooves 13b are formed on a spherical outer circumferential surface 13a in the axial direction and a connecting hole for connecting a shaft is formed in a center section, six torque transmission balls 14 disposed on ball tracks formed by a pair composed of the a ball groove 12b on the outer ring 12 and a ball groove 13b on the inner ring 13, and a cage 15 having pockets 15c for storing the torque transmission balls 14, a convex spherical outer circumferential surface 15a that is in contact with and guided by the inner circumferential surface 12a of the outer ring 12, and a concave spherical inner circumferential surface 15b that is in contact with and guided by the outer circumferential surface 13a of the inner ring 13 and in which a spherical surface center OC0 of the outer circumferential surface 15a and a spherical surface center OCI of the inner circumferential surface 15b are offset to opposite sides of a pocket center O in the axial direction. In the slide-type constant velocity universal joint, a ratio of ball diameter to outer ring outer diameter is 0.21 to 0.25, a ratio of ball pitch diameter to outer ring outer diameter is 0.64 to 0.68, a contact angle of the ball groove is 30° to 35°, a contact ratio of the ball groove is 1.02 to 1.08, and a ratio of cage offset amount to ball pitch diameter is 0.07 to 0.09.