Tripod Joint Stop Layout for Lower ACFG and Higher Torque
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Solution Overview
Problem
Existing tripod joints face challenges in reducing Axial Cyclic Force Generation (ACFG) forces and ensuring the mountability of the roller body on the trunnion, with limitations in deflection angle and transmittable torques due to design constraints such as narrow transition areas and excessive axial forces.
Innovation Solution
The tripod joint design incorporates a more advantageous arrangement of stops, allowing for unrestricted displacement of the inner ring relative to the trunnion along the trunnion axis during intended operation, with a first stop limiting displacement along the axis of rotation and a second stop controlling displacement in traction mode, while a third stop facilitates disassembly protection, enhancing the joint's resilience and torque transmission capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner ring is fixed to the outer ring with respect to the direction along the axis of rotation by circlips, then the roller body is secured in position, but the mountability of the roller body on the trunnion is limited and ACFG forces increase
Solution Approach 1:
The tripod joint is divided into separate components (outer joint part, inner joint part with trunnions, roller bodies) that can be assembled independently. The inner ring can be mounted on the trunnion before assembly into the outer joint part, improving ease of manufacture while maintaining position stability through the stop arrangement
Solution Approach 2:
The inner ring acts as an intermediary component between the trunnion and the outer joint part. It provides a mounting interface on the trunnion and a positioning interface in the outer joint part, facilitating easier assembly while maintaining reliability
2Volume of moving object
If the transition area between trunnion and central body is narrow, then the joint is more compact, but the transmittable torques are limited
Solution Approach 1:
The transition area is designed with locally optimized geometry, including specific surface profiles and reinforcement features in the critical torque transmission zones. This allows the transition area to be compact overall while maintaining sufficient torque transmission capability through localized structural enhancements
3Reliability
If the deflection angle is limited to 23-26 degrees, then the joint maintains optimal contact between trunnions and sliding surfaces, but the application range is restricted
Solution Approach 1:
The joint incorporates dynamic elements including the displaceable inner ring and roller bodies that can accommodate varying deflection angles. The stop arrangement allows the inner ring to move relative to the outer ring, enabling the joint to maintain optimal contact conditions across a wider range of deflection angles than traditional fixed designs
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 design reduces ACFG forces, improves the mountability of the roller body, and increases the joint's deflection angle and torque transmission capabilities, thereby expanding its application range.
Implementation Method 1
bearing bodies arranged between the outer ring and the inner ring
Implementation Method 2
The trunnion contacts the bearing body or the inner ring of the roller body via so-called sliding surfaces (contact surfaces), which are designed in the shape of a spherical segment. These sliding surfaces are aligned in a circumferential direction around the second longitudinal axis, so that a torque acting around the longitudinal axes of the joint is transmitted via the sliding surfaces of the trunnion to the roller body
Data Source
AI summary
A tripod joint can include a joint outer part with a first longitudinal axis and a cavity running parallel to the first longitudinal axis with an open end, three recesses running parallel to the first longitudinal axis being formed in the joint outer part, and a joint inner part with a second longitudinal axis., The tripod joint can include at least one central body on which three trunnions are formed with trunnion axes extending radially from the second longitudinal axis, wherein a roller body is arranged on each of the trunnions, which roller body has at least one outer ring and an inner ring rotatable therewith about a common axis of rotation, as well as bearing bodies arranged between the outer ring and the inner ring; wherein each roller body is movably received in the recesses along the first longitudinal axis.