CV Joint Track Groove Layout for High Operating Angles
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Solution Overview
Problem
The existing fixed type constant velocity universal joints, particularly those of the track groove crossing type, face challenges in achieving high operating angles due to insufficient effective track length, leading to torque loss and heat generation issues, especially at frequently used operating angles.
Innovation Solution
The design incorporates arc-shaped first track groove portions with curvature centers offset to the opening side and second track groove portions of different shapes to increase effective track length, allowing for high operating angles while maintaining efficiency and reducing torque loss and heat generation. The first track groove portions are inclined in opposite directions, and the second track groove portions are connected to the first track groove portions on the opening side, enhancing the joint's operational range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the curvature center of the track groove is positioned at the joint center, then the joint structure is simplified, but the effective track length becomes insufficient at high operating angles
Solution Approach 1:
The track groove is divided into two distinct portions: a first track groove portion with curvature center at the joint center for low operating angles, and a second track groove portion with curvature center offset to the opening side for high operating angles. This segmentation allows each portion to be optimized for its specific operating range, resolving the contradiction between structural simplicity and effective track length.
Solution Approach 2:
The joint dynamically transitions between using the first track groove portion and the second track groove portion based on the operating angle. At low operating angles, the ball engages the first portion; at high operating angles, it engages the second portion. This dynamic adaptation allows the joint to maintain optimal performance across the full operating range without compromising structural simplicity.
2Length of moving object
If the curvature center of the track groove is offset to increase effective track length, then high operating angles are achieved, but torque loss and heat generation increase at frequently used operating angles
Solution Approach 1:
Different portions of the track groove have different curvature center positions optimized for different operating conditions. The first track groove portion has curvature center at the joint center for optimal performance at frequently used low operating angles, while the second portion has offset curvature center for high operating angles. This local differentiation resolves the contradiction by providing optimal geometry only where needed.
3Adaptability or versatility
If a large inlet chamfer is formed to achieve high operating angles, then the operating angle range is increased, but the effective track length of the outer joint member becomes insufficient
Solution Approach 1:
The track groove is segmented into two portions with different curvature characteristics. The second track groove portion, positioned on the opening side with offset curvature center, compensates for the track length loss caused by large inlet chamfer, allowing both high operating angles and sufficient effective track length to be achieved simultaneously.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3c
AI summary
Track grooves (7) of an outer joint member (2) include: first track groove portions (7a) positioned on an interior side; and second track groove portions (7b) positioned on an opening side. Each of the first track groove portions (7a) is formed into an arc shape having a curvature center at a position offset to the opening side with respect to a joint center. The first track groove portions (7a) are inclined in a peripheral direction of the outer joint member (2) with respect to a joint axial line (N-N) and adjacent to each other in the peripheral direction with their inclination directions opposite to each other. Each of the second track groove portions (7b) is formed into a different shape from the arc shape of the each of the first track groove portions (7a) so as to increase an effective track length at a maximum operating angle. The each of the second track groove portions (7b) is connected to the each of the first track groove portions (7a) at a position on the opening side with respect to the joint center (O). Each of track grooves (9) of an inner joint member (3) is formed so as to be mirror-image symmetrical with corresponding one of the paired track grooves (7) of the outer joint member (2) with respect to a joint center plane (P) at an operating angle of 0°.