Ball-and-Socket Joint Truncated Sphere Raceway Torque Transfer
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Solution Overview
Problem
Ball-and-socket joint members experience high torque and wear during swivelling movements, leading to reduced service life and increased manufacturing complexity due to high friction and stress on the outer ring.
Innovation Solution
The joint member features a truncated sphere-shaped inner raceway and complementary groove-shaped outer raceway, transferring swivelling torque to the inner ring and reducing contact pressure on the outer ring, allowing for the use of less stressed stainless steel and simplifying thermal treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer ring has a standard outer raceway, then the joint member allows rotation movement, but high torque and friction occur during swivelling movements causing wear on the outer ring
Solution Approach 1:
The patent inverts the traditional ball-and-socket joint configuration by making the inner ring spherical instead of the outer ring. This inversion transfers the swivelling torque from the outer ring to the inner ring, eliminating wear on the outer ring during swivelling movements and significantly improving the joint member's service life.
Solution Approach 2:
The patent applies different geometric qualities to different parts: the inner ring has a spherical surface for swivelling movements, while the outer ring has a grooved raceway for guiding rotation. This local differentiation optimizes each component's function and reduces overall friction and wear.
2Loss of energy
If the inner ring has a truncated sphere-shaped inner raceway, then swivelling torque is transferred to the inner ring reducing friction, but the contact pressure distribution changes
Solution Approach 1:
The patent employs a spherical inner raceway surface that contacts the balls during swivelling movements. This curved surface geometry reduces friction compared to flat surfaces by allowing rolling contact, thereby reducing energy loss during swivelling operations.
3Stress or pressure
If the outer ring has a groove-shaped outer raceway, then the contact surface area increases reducing contact pressure, but the groove structure adds manufacturing complexity
Solution Approach 1:
The outer ring features a localized grooved raceway structure that concentrates the contact area between the balls and the outer ring. This grooved design increases the contact surface area specifically where needed, reducing contact pressure without requiring complex modifications to the entire outer ring structure.
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 design reduces swivelling torque and friction, increasing the service life of the joint member, enabling the use of economically advantageous and corrosion-resistant stainless steel and simplifying manufacturing processes.
Implementation Method 1
the friction and the swivelling torques applied to the outer ring are reduced
Implementation Method 2
the torque exerted during a swivelling movement on the outer ring is generally high
Data Source
AI summary
The ball-and-socket joint member includes an inner ring, of a general shape of revolution around a first axis, having an outer surface provided with an inner raceway, an outer ring, of a general shape of revolution around a second axis, having an inner surface provided with an outer raceway, and at least one row of balls aligned circumferentially, extending radially between the inner raceway and the outer raceway. The outer surface of the inner ring comprises a portion with a generally truncated sphere shape, forming the inner raceway. The inner surface of the outer ring comprises, for each row of balls, a groove of complementary shape to that of the balls of this row, said groove forming the outer raceway.