Fixed-Center Constant Velocity Joint with Segmented Grooves
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Solution Overview
Problem
Existing ball-type constant velocity joints struggle to balance compactness with angle capabilities and NVH characteristics, while also preventing telescoping movement and maintaining mechanical efficiency.
Innovation Solution
A fixed-center constant velocity joint design featuring a concentrically located race and cage with longitudinal and helical grooves, preventing telescoping through cross groove passages and reducing contact stresses, allowing for compact and robust construction with enhanced angle capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If eight-ball joints are used, then compactness is improved, but angle capabilities deteriorate
Solution Approach 1:
The joint is segmented into inner and outer races with separate groove systems. The inner race has grooves for four balls, while the outer race has grooves for four additional balls, allowing independent optimization of each ball set for different functions.
Solution Approach 2:
The groove geometry transitions from traditional circular cross-sections to oval or rectangular cross-sections with flat bottoms. This dimensional change in groove shape allows better ball retention and enables the joint to achieve both compactness and large angle capabilities.
2Adaptability or versatility
If stroking joints are used, then angle capabilities are improved, but NVH characteristics deteriorate
Solution Approach 1:
Instead of allowing telescoping movement (stroking) to achieve angle capabilities, the invention inverts the approach by using a fixed-center design where the races are constrained to remain concentric. The angle capability is achieved through the groove geometry and ball arrangement rather than through radial movement.
Solution Approach 2:
The grooves are designed with specific curved geometries including oval and rectangular cross-sections with rounded corners. These curved geometries guide the balls smoothly during rotation, reducing vibration and improving NVH characteristics while maintaining large angle capabilities.
3Object-generated harmful factors
If fixed-center design is used, then NVH characteristics are improved, but telescoping capability deteriorates
Solution Approach 1:
The fixed-center design dynamically maintains concentricity between inner and outer races through the groove-ball interaction. The grooves are shaped to automatically center the races during operation, providing dynamic stability that improves NVH characteristics while the joint still accommodates large operating angles.
4Adaptability or versatility
If six-ball joints are used, then angle capabilities are improved, but compactness deteriorates
Solution Approach 1:
The eight-ball joint segments the ball functions: four balls handle torque transmission in the primary plane, while the other four balls provide support and stability for large angle operations. This segmentation allows compact packaging while achieving six-ball equivalent angle capabilities.
Data Source
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AI summary
A fixed-center constant velocity joint (20) has a race (22) located concentrically to a rotational first axis (24), and a ring-shaped cage (26) located concentrically to a rotational second axis (27). Both the race and the cage are centered to a common center point lying on the first and second axes regardless of the angular state of the joint. A spherical surface (44) carried by the race radially opposes a spherical face (102) carried by the cage for angular movement with respect to the center point. The surface and face are in close or contacting relationship to prevent telescoping movement with respect to the first and second axes.