CV Joint Ball Track Layout for High Torque at Large Angles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Constant-velocity rotary joints face challenges in maximizing torque transmission while minimizing structural volume and ensuring smooth operation, especially at large bending angles above 50°, where existing designs often compromise on torque capacity and mechanical stability.
Innovation Solution
The design incorporates two types of ball track pairs: neutral balls with concentrically extending tracks for high torque transmission across the bending angle range and controlled balls with S-shaped tracks to steer balls into the plane of symmetry, reducing friction losses and axial loads, and ensuring reliable control at small bending angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional single-type ball track design is used, then structure is simple, but torque transmission capacity is insufficient at large bending angles
Solution Approach 1:
The ball track configuration is segmented into two distinct types: concentric ball tracks for neutral balls and S-shaped ball tracks for controlled balls. This segmentation allows each type to perform its specific function optimally, with neutral balls providing torque transmission and controlled balls providing steering control, thereby resolving the contradiction between torque capacity and structural complexity.
Solution Approach 2:
Different regions of the joint employ different ball track configurations tailored to local requirements. The concentric ball tracks are positioned where neutral balls can maintain constant velocity, while S-shaped ball tracks are positioned where controlled balls need to steer into the plane of symmetry. This local differentiation optimizes torque transmission at large angles while maintaining control at small angles.
2Reliability
If controlled balls with S-shaped tracks are used, then joint control is improved, but friction losses increase
Solution Approach 1:
The system dynamically switches between two ball types based on operating conditions. At small bending angles, controlled balls with S-shaped tracks actively steer to maintain joint control. At large bending angles, neutral balls with concentric tracks take over to minimize friction and energy loss. This dynamic allocation resolves the contradiction between control reliability and energy efficiency.
Solution Approach 2:
The ball track geometry parameter changes from S-shaped to concentric based on the bending angle. The S-shaped tracks provide the necessary steering control at small angles, while the concentric configuration minimizes frictional contact at large angles. This parameter transformation allows the system to adapt to different operating regimes, balancing control and energy loss.
3Strength
If neutral balls with concentric tracks are used, then torque transmission is maximized, but joint control deteriorates
Solution Approach 1:
The ball population is segmented into neutral balls and controlled balls, each assigned to specific track types. Neutral balls in concentric tracks maximize torque transmission, while controlled balls in S-shaped tracks maintain joint control. This functional segmentation resolves the contradiction by distributing different tasks to different ball types rather than requiring a single ball type to perform all functions.
Solution Approach 2:
The constant velocity joint system performs multiple functions through different ball types: torque transmission, joint control, and friction reduction. By making the system multi-functional through the coexistence of neutral and controlled balls, it can simultaneously achieve high torque capacity and reliable control across the entire bending angle range.
4Strength
If joint structure is optimized for large bending angles, then torque capacity increases, but mechanical stability at small angles decreases
Solution Approach 1:
The ball track configuration is locally optimized for different angular positions. S-shaped tracks provide stability and control at small angles through active steering, while concentric tracks provide optimal torque transmission at large angles. This local optimization ensures mechanical stability is maintained across the entire operating range without sacrificing torque capacity at extreme angles.
Solution Approach 2:
The system dynamically adapts its ball track engagement based on the bending angle. At small angles, controlled balls actively engage S-shaped tracks for stability. As the angle increases, neutral balls engage concentric tracks to maximize torque capacity. This dynamic adaptation resolves the contradiction between stability and torque capacity across different operating conditions.
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 maximizes the ratio of torque transmission capacity to construction space, maintains mechanical stability, and reduces friction losses by allowing pure rolling motion of neutral balls, while controlled balls ensure reliable joint operation at high bending angles.
Implementation Method 1
one of the balls is accommodated in each track pairing... a ball runs in each case along one or several outer contact lines in the outer ball track, and along one or more inner contact lines in the inner ball track
Data Source
AI summary
A constant-velocity joint for torque-transmission, in which a first type of track pairs of ball tracks is configured in such a manner that the centers of curvature of the center lines of the ball tracks are situated in the joint center plane when the joint is straight. A second type of track pairs of ball tracks is configured in such a manner that their center lines have at least two portions. The respective center line of the outer ball tracks of the second type of track pairs has at least one inner portion and one outer portion, wherein the inner portion is situated on the connection side of the outer joint portion, while the outer portion is situated on the opening side of the outer joint portion, and the inner portion is curved.