Sliding Tripod CVJ Thrust Force Reduction via Spheroidality
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Solution Overview
Problem
Existing sliding type tripod constant velocity joints face issues with induced thrust force, rotation backlash, and maximum joint angle limitations due to friction and interference problems, which affect vibration, noise, and compactness.
Innovation Solution
A sliding type tripod constant velocity joint design featuring a tubular outer ring with raceway grooves, oscillating intermediate members, and a cage system that supports rolling elements to ensure they roll smoothly along the raceway grooves, reducing friction and allowing for increased joint angles without enlarging the joint's diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a cylindrical tripod shaft part and cylindrical inner peripheral surface of roller are used, then the structure is simple, but induced thrust force is generated causing vibration and noise
Solution Approach 1:
The patent applies spheroidality by forming the outer peripheral surface of the tripod shaft part with a spherical protruding form and the inner peripheral surface of the roller with a spherical recessing form. This curved surface design enables the roller to constantly correspond to the direction in which the raceway groove extends, preventing sliding and eliminating induced thrust force that causes vibration and noise.
2Stability of the object's composition
If the roller is constantly located coaxially with the tripod shaft part, then the structure is stable, but sliding arises between roller and raceway groove generating induced thrust force
Solution Approach 1:
The spherical protruding form on the tripod shaft part and spherical recessing form on the roller enable the roller to constantly correspond to the direction in which the raceway groove extends. This curved surface design prevents sliding between the roller and raceway groove, eliminating induced thrust force while maintaining stable operation.
3Device complexity
If spherical rolling elements are used, then the structure is simple, but large resistance is generated due to sliding and rolling resistance
Solution Approach 1:
The patent changes the shape parameter of the rolling elements from spherical to needle-shaped (cylindrical). This parameter change reduces the contact area and minimizes sliding and rolling resistance between the rolling elements and the raceway groove, thereby reducing energy loss while maintaining structural simplicity.
4Adaptability or versatility
If the joint diameter is increased to allow larger joint angles, then the maximum joint angle increases, but the compactness is reduced
Solution Approach 1:
The spherical protruding form and spherical recessing form enable the roller to constantly correspond to the direction in which the raceway groove extends, preventing sliding and reducing induced thrust force. This allows the joint to achieve larger maximum joint angles without requiring an increased joint diameter, thereby maintaining compactness while improving adaptability.
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
The design effectively reduces induced thrust force, minimizes rotation backlash, and increases the maximum joint angle, enhancing the joint's durability and reducing vibration and noise while maintaining a compact size.
Implementation Method 1
a plurality of rolling elements provided between the side surfaces of a corresponding one of the raceway grooves and power transmission surfaces of the pair of intermediate members opposing the side surfaces to the corresponding one of the raceway grooves so as to roll along the side surfaces of the corresponding one of the raceway grooves
Data Source
AI summary
A sliding type tripod constant velocity joint includes an outer ring of a tubular form having three raceway grooves which are formed on an inner peripheral surface and which extend in a direction of a rotation axis of the outer ring, a tripod including a boss part connected to a shaft and three tripod shaft parts which are provided upright so as to extend outward in a radial direction of the boss part from an outer peripheral surface of the boss part and which are inserted into the raceway grooves, respectively, and a pair of intermediate members which are arranged so as to sandwich a corresponding one of the tripod shaft parts from both sides of side surfaces of the raceway grooves and which are provided so as to be oscillated relative to the corresponding one of the tripod shaft parts.