CV Ball Joint Track Geometry for Uniform Force Transmission
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Solution Overview
Problem
Constant-velocity ball joints experience non-uniform force transmission as deflection angles increase, leading to varying stress on balls, which is a challenge in motor vehicle applications where space, weight, and cost efficiency are critical.
Innovation Solution
The design features inner center lines with a convex progression, reducing spacing from the axis of rotation, and a cage guided by a spherical surface, ensuring uniform force distribution across balls during deflection and revolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the ball track base or center line is at a constant spacing from the axis of rotation, then the joint structure is simpler and easier to manufacture, but the force transmission becomes non-uniform as deflection angles increase
Solution Approach 1:
The patent applies local quality by making the ball track center lines have different spacings from the axis of rotation at different locations. Specifically, the center lines are positioned closer to the axis of rotation in certain regions rather than maintaining a constant spacing, which creates non-uniform geometric properties that compensate for the non-uniform force transmission during deflection.
Solution Approach 2:
The patent changes the geometric parameter of the ball track center line spacing from a constant value to a variable value that changes along the track. This parameter change is designed to homogenize the stress distribution on the balls during deflection, transforming the uniform spacing configuration into a non-uniform one that achieves uniform force transmission.
2Adaptability or versatility
If the joint inner part is displaced relative to the joint outer part by a large total displacement travel, then the adaptability of the joint is improved, but the stress on the balls becomes more non-uniform during deflection
Solution Approach 1:
The patent addresses this contradiction by implementing local quality in the ball track geometry. The center lines of the ball tracks are positioned at varying distances from the axis of rotation, with smaller spacings in specific regions. This localized geometric modification ensures that even with large displacement travel providing high adaptability, the stress distribution on the balls remains more uniform during deflection.
3Adaptability or versatility
If the cage is guided via a spherical contact surface, then the joint allows for larger deflection angles and better versatility, but the structural complexity increases
Solution Approach 1:
The patent utilizes spheroidality by employing a spherical contact surface for guiding the cage. This curved surface geometry enables the joint to accommodate larger deflection angles while maintaining smooth motion. The spherical configuration allows the cage to pivot effectively, providing the necessary versatility for applications requiring significant angular movement.
Data Source
AI summary
Constant-velocity ball joint, having at least a joint outer part with an axis of rotation and with outer ball tracks and with outer center lines, a joint inner part with inner ball tracks and inner center lines, and a large number of torque-transmitting balls which are each guided in mutually associated outer ball tracks and inner ball tracks.