Constant-Velocity Joint Inner Roller Local Quality
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Solution Overview
Problem
Existing constant-velocity joints face challenges in reducing size and weight while maintaining sufficient clearance between holders and rollers, which hinders tilting and increases sliding resistance.
Innovation Solution
A constant-velocity joint design featuring guide grooves in the outer member and roller assemblies with inner rollers having a minimal inside diameter at contact points and a large center of gravity, allowing for easy tilting and reduced frictional resistance, even when compacted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the constant-velocity joint is reduced in size and weight, then the energy consumption is reduced, but the clearance between holders and rollers becomes smaller making tilting difficult
Solution Approach 1:
The inner roller is designed with non-uniform wall thickness where the wall thickness is smaller at the contact region with the holder compared to other regions. This creates a localized thin-walled structure at the contact point, providing greater clearance and facilitating easier tilting of the holder while maintaining overall compact dimensions of the constant-velocity joint.
Solution Approach 2:
The patent changes the geometric parameter of the inner roller by varying its wall thickness distribution. Specifically, the inner roller has a minimal inside diameter at the contact point with the holder, creating a localized parameter change that increases clearance and enables easier tilting operation without increasing the overall size of the joint.
2Volume of moving object
If the constant-velocity joint is reduced in size, then the overall dimensions are reduced, but the clearance for tilting becomes insufficient
Solution Approach 1:
The inner roller employs non-uniform wall thickness with a localized thin section at the holder contact region. This local quality variation provides sufficient tilting clearance in the critical area while maintaining compact overall dimensions of the constant-velocity joint, resolving the contradiction between small volume and adequate clearance length.
Solution Approach 2:
The patent addresses the clearance issue by transitioning from a uniform dimensional approach to a variable dimensional approach. By making the inner roller wall thickness vary along its circumference, the design creates additional clearance space in the radial dimension at the contact point, enabling sufficient tilting clearance without increasing the overall volume of the joint.
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
Ensures sufficient clearance for tilting and minimizes frictional resistance, enabling efficient power transmission with reduced size and weight.
Implementation Method 1
Each of the roller assemblies includes an inner roller, and an outer roller, which is mounted externally of the inner roller through rolling members
Data Source
AI summary
In a constant-velocity joint, an inner member thereof includes holders that serve to retain respective roller assemblies. When each of the holders is hypothetically divided into three equal parts made up of a proximal end portion, an intermediate portion, and a distal end portion from a side of an annular member, an inner wall surface of an inner roller of the roller assembly contacts only a side wall surface of the proximal end portion. The inner roller preferably has an inside diameter, which is minimum at a contact point that contacts the side wall surface of the proximal end portion. More specifically, the inside diameter of the inner roller gradually expands in diameter from the contact point to a side that faces toward the annular member, and further, gradually expands in diameter from the contact point to a side that faces toward the distal end portion.