Fixed Ball Joint Symmetrical Track Cross-Sections
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Solution Overview
Problem
Constant velocity joints with existing designs face disadvantageous load conditions at track edges under torque, depending on the torque direction, which affects their load-bearing capacity and efficiency.
Innovation Solution
The design features symmetrical track cross-sections for both outer and inner ball tracks relative to specific radial rays and straight lines, ensuring uniform load distribution and improved force introduction regardless of torque direction, with optional variations in track shapes and configurations to maintain symmetry and control angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If circular arches are used for ball track cross-sections with axes of symmetry in planes containing track center lines, then the joint structure is simple and manufacturable, but disadvantageous load conditions occur at track edges under torque depending on torque direction
Solution Approach 1:
The patent applies asymmetry by positioning the axis of symmetry of the ball track cross-section at an angle φ relative to the plane containing the track center line, rather than aligning them directly. This asymmetric orientation (where φ differs from the conventional 0° alignment) redistributes the stress distribution under torque, preventing concentrated loads at track edges while maintaining manufacturing feasibility through standardized angular positioning.
2Reliability
If track cross-sections are symmetrical relative to radial rays from longitudinal axes through ball centers, then uniform load distribution is achieved independent of torque direction, but manufacturing complexity increases due to precise angular positioning requirements
Solution Approach 1:
The patent changes the angular parameter φ defining the orientation of the track cross-section symmetry axis relative to the radial plane. By optimizing this parameter within specific ranges (e.g., 10°-30° from the radial direction), the design achieves uniform load distribution under bidirectional torque while maintaining manufacturability. This parameter optimization balances performance uniformity with fabrication feasibility.
3Strength
If two balls are received in each cage window to increase load bearing capacity, then torque transmitting capability is enhanced, but the joint complexity and space requirements increase
Solution Approach 1:
The patent merges multiple torque transmission functions into a single ball cage structure by accommodating two balls per cage window. This consolidation approach increases load-bearing capacity while maintaining a compact design, as the combined action of paired balls provides enhanced torque transmission without requiring separate cage structures for each ball.
Solution Approach 2:
The patent utilizes the radial dimension within the ball cage by positioning two balls at different radial locations or angular positions within the same cage window. This dimensional arrangement allows both balls to contribute to torque transmission simultaneously, effectively increasing load capacity without proportionally increasing the overall joint size or cage complexity.
Data Source
AI summary
A constant velocity fixed joint having an outer joint part (12) with outer ball tracks (221, 222), an inner joint part (13) with inner ball tracks (231, 232), the outer ball tracks and the inner ball tracks forming pairs of tracks (211, 231; 222, 232), the pairs of tracks each accommodate a torque transmitting ball (141, 142). Each two adjoining pairs of tracks comprise outer ball tracks with center lines in planes extending substantially parallel relative to one another, as well as inner ball tracks with center lines in planes extending substantially parallel relative to one another. An annular ball cage (16) is positioned between the outer joint part (12) and the inner joint part (13). In an aligned joint, centers of the balls are held by the ball cage in the joint center plane and when the joint is articulated, they are guided onto the angle-bisecting plane between the longitudinal axes. The track cross-sections of the outer ball tracks and of the inner ball tracks of each pair of tracks are symmetrical relative to the axes of symmetry which, together with the planes, form identically sized angles opening in opposite directions, and each comprise a common point.