Constant Velocity Joint Groove Contact Geometry for Low Sliding Resistance
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Solution Overview
Problem
Constant velocity joints experience increased sliding resistance and vibration due to slippage between rollers and guide grooves, leading to abnormal noise, which existing designs fail to adequately mitigate.
Innovation Solution
The constant velocity joint features an outer member with guide grooves and an inner member with retaining members having alternating contact and non-contact portions, where the contact portions are designed to maintain parallel or perpendicular alignment with the grooves, and the second arcuate portion of the retaining members has a smaller radius of curvature, reducing resistance and induced thrust by preventing roller assembly inclination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rollers slide within guide grooves while rotating and tilting, then the constant velocity joint can accommodate working angles, but sliding resistance increases due to slippage between roller and guide groove surfaces
Solution Approach 1:
The retaining member features a curved surface with a specific radius of curvature that matches the roller surface, enabling rolling contact instead of sliding contact. This curvature design allows the roller to roll along the curved surface while accommodating working angles, thereby reducing sliding resistance and preventing slippage between contact surfaces
Solution Approach 2:
The invention transitions from a static guiding mechanism to a dynamic rolling mechanism. The roller assembly is designed to dynamically roll along the curved surface of the retaining member while accommodating angular changes, converting harmful sliding friction into beneficial rolling motion that reduces resistance
2Object-affected harmful factors
If sliding resistance increases as rollers rotate, then vibration and abnormal noise occur, but reducing contact area may compromise load bearing capacity
Solution Approach 1:
The curved surface of the retaining member is designed with specific local geometric properties (radius of curvature) that optimize the contact zone. This local quality design creates an optimal contact area that is sufficient to bear loads while minimizing the contact perimeter where friction and slippage occur, thereby reducing vibration and noise without compromising load bearing capacity
Solution Approach 2:
The invention changes the geometric parameters of the contact surface by introducing a curved surface with a specifically designed radius of curvature. This parameter change transforms the contact mechanism from sliding to rolling, reducing friction coefficients and preventing the generation of vibration and noise while maintaining adequate load bearing capacity through optimized contact geometry
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 reduces sliding resistance and enhances the efficiency of rotary drive power transmission while minimizing wear and vibration, resulting in improved durability and noise reduction.
Implementation Method 1
an outer roller mounted via rolling members outwardly of the inner roller
Data Source
AI summary
In a lateral cross section passing through a center of a trunnion in the form of a retaining member that constitutes part of a constant velocity joint, and an orthogonal site where a virtual tangent line at a contact region is perpendicular to a longitudinal direction of a guide groove, a curved surface having a first arcuate portion and a second arcuate portion is formed. The second arcuate portion is contiguous with the first arcuate portion, and has a smaller radius of curvature than the first arcuate portion. Further, the first arcuate portion and the second arcuate portion are arranged in this order from a side in proximity to an annular member of the trunnion.