Constant Velocity Joint Ball Track Geometry for Torque Capacity
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Solution Overview
Problem
Existing constant velocity fixed joints have a limited torque transmitting capacity due to large radial ball movement and resulting cage thickness, which reduces the degree of ball envelopment and track depth.
Innovation Solution
The design features ball tracks with center lines that depart radially inward and outward from a reference radius, allowing for reduced radial ball movement and thinner cage thickness, increasing the torque transmitting capacity by enhancing ball envelopment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the radial ball movement is reduced, then the cage thickness can be reduced, but the track depth must be increased to maintain ball envelopment
Solution Approach 1:
The patent changes the geometric parameters of the ball track center lines by introducing turning points and radial deviations from straight paths. The center lines depart from reference radii and incorporate curved segments, transforming the ball movement from simple radial oscillation to a more complex path that achieves both reduced cage thickness and maintained ball envelopment, thereby resolving the contradiction between cage thickness and torque capacity
2Volume of moving object
If the cage thickness is reduced, then the track depth increases, but the ball envelopment degree must be maintained to preserve torque capacity
Solution Approach 1:
The patent applies curvature to the ball track center lines by introducing turning points and radial deviations. Instead of straight or simple curved tracks, the center lines follow complex curved paths that depart from reference radii and return, creating spherical-like motion patterns. This curvature design allows the balls to maintain proper envelopment by the tracks while enabling thinner cage construction, as the curved paths keep balls positioned optimally within the reduced cage thickness
3Strength
If the opening angle α opens from aperture side to attaching side, then the joint strength is increased, but the radial ball movement pattern changes affecting cage design
Solution Approach 1:
The patent introduces asymmetry in the ball track design by having the opening angle α open from the aperture side to the attaching side, rather than being symmetric. The track center lines incorporate asymmetric turning points and radial deviations that are not uniformly distributed. This asymmetric configuration optimizes the joint strength by directing forces favorably while simultaneously controlling the radial ball movement pattern to enable reduced cage thickness, resolving the contradiction between strength and ease of operation
Data Source
AI summary
A constant velocity fixed joint. The center line (M22) of the outer ball tracks (22) towards a first side (S1) departs, radially inwardly, a reference radius centered in the point of intersection between a perpendicular line on tangents (T22) at the center line (M22), and the longitudinal axis (L12). The center line (M23) of the inner ball tracks (23) towards a second side (S2) departs, radially inwardly, a reference radius centered in the point of intersection of a perpendicular line on the tangent at the center line (M23), and the longitudinal axis (L13). In the outer joint part, from the joint center plane (EM) to the second side (S2), the center line (M22) moves beyond the reference radius radially outwardly. In the inner joint part (13), from the joint center plane (EM) to the first side (S1), the center line (M23) moves beyond the reference radius, radially outwardly.