Constant Velocity Universal Joint Spherical Surface Angle
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Solution Overview
Problem
Fixed type constant velocity universal joints face difficulties in maintaining smooth rotation and sufficient strength at large operating angles and high torque due to excessive load on the cage, caused by reduced contact area between the inner and outer spherical surfaces.
Innovation Solution
The design includes an outer joint member with a spherical surface angle of 12.5° or more on the joint opening side and notched portions on the outer spherical surface portions of the inner joint member, which increases the contact area and reduces the load on the cage, allowing for smooth rotation and enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If notched portions are formed in the outer spherical surface of the inner joint member to facilitate assembly, then ease of assembly is improved, but the contact area between the inner joint member and cage is reduced, leading to excessive load on the cage at large operating angles
Solution Approach 1:
The patent changes the geometric parameters of the outer spherical surface by defining a minimum spherical surface angle of 12.5° or more. This parameter change ensures sufficient contact area between the inner joint member and cage, preventing excessive load concentration while maintaining the notched portions for assembly facilitation.
2Strength
If the spherical surface angle is increased to 12.5° or more to increase contact area, then the load distribution on the cage is improved, but the assembly process becomes more complex
Solution Approach 1:
The patent establishes a specific parameter threshold (spherical surface angle ≥ 12.5°) that optimizes the balance between contact area and assembly complexity. This parameter definition provides clear manufacturing guidelines while ensuring sufficient load distribution capability.
3Strength
If the contact area is increased by adjusting the spherical surface geometry, then the cage strength is improved, but the precision of the spherical surface machining becomes more critical
Solution Approach 1:
The patent defines a minimum spherical surface angle of 12.5° that provides an optimal balance between contact area and manufacturing feasibility. This parameter specification ensures sufficient cage strength while maintaining reasonable machining precision requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures a sufficient contact area to bear large spherical surface forces, reducing excessive loads on the cage and ensuring smooth, reliable operation of the universal joint even at large operating angles and high torque conditions.
Implementation Method 1
multiple balls (16) interposed between the track grooves (11) of the outer joint member (12) and the track grooves (14) of the inner joint member (15), for transmitting torque
Implementation Method 2
a cage (17) interposed between the inner spherical surface (10) of the outer joint member (12) and the outer spherical surface (13) of the inner joint member (15), for retaining the balls (16)
Implementation Method 3
the contact area between the outer spherical surface of the inner joint member and the inner spherical surface of the cage is decreased correspondingly to the notched portions thus formed. As a result, when the joint forms a large operating angle and large torque is applied thereto, the inner spherical surface of the cage receives the spherical surface force from the inner joint member within a small contact area
Data Source
Figure 1
Figure 2
Figure 3a~4
AI summary
Provided is a fixed type constant velocity universal joint capable of securing smooth rotation and reducing a load on a cage even at a large operating angle and at a time of bearing large torque. The fixed type constant velocity universal joint includes an outer joint member having opened one end and an inner spherical surface in which multiple track grooves are circumferentially formed in an axial direction; an inner joint member (15, 25) having an outer spherical surface (13, 23) in which multiple track grooves (14, 24) paired with the track grooves of the outer joint member are circumferentially formed in the axial direction and multiple outer spherical surface portions (19, 29) circumferentially arranged; multiple balls interposed between the track grooves of the outer joint member and the track grooves (14, 24) of the inner joint member (15, 25), for transmitting torque; and a cage interposed between the inner spherical surface of the outer joint member and the outer spherical surface (13, 23) of the inner joint member (15, 25), for retaining the balls. A spherical surface angle (α10, α20) of the outer spherical surface (13, 23) of the inner joint member (15, 25), which is positioned on a joint opening side, is set to 12.5° or more.