Tripod CV Joint Raceway Groove Shape for Vibration and Weight Reduction
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Solution Overview
Problem
The tripod type constant velocity universal joint experiences friction-induced vibration due to roller contact with the ceiling surface of the raceway groove, and there is room for improvement in reducing the size and weight of the outer ring.
Innovation Solution
The design features a groove-orthogonal sectional shape of the ceiling surface as a line shape including at least part of a target contour line, positioned away from the central axis of the outer ring, allowing for reduced contact with the roller and minimizing forcing power generation, thereby enabling a smaller outer ring size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the groove-orthogonal sectional shape of the ceiling surface is formed in a circular arc shape centered on the central axis of the outer ring, then the contact of the roller with the ceiling surface during pitching is suppressed, but a clearance is present between the roller and the ceiling surface, resulting in larger outer ring size and weight
Solution Approach 1:
The invention changes the geometric parameters of the ceiling surface from a circular arc shape centered on the central axis to a line shape based on the projected contour of the roller end face. This parameter change allows the ceiling surface to be positioned closer to the center of the outer ring, reducing the outer ring's size and weight while maintaining suppression of friction-induced vibration through controlled roller contact.
2Weight of stationary object
If the ceiling surface is positioned closer to the center of the outer ring to reduce size and weight, then the outer ring size and weight are reduced, but the roller may come into contact with the ceiling surface during pitching, generating friction and forcing power
Solution Approach 1:
The invention applies local quality by designing the ceiling surface with a specific line shape that corresponds to the projected contour of the roller end face. This localized geometric design ensures that contact between the roller and ceiling surface occurs only in specific regions and under specific conditions (when the roller pitches by the predetermined angle or more), thereby generating forcing power only when necessary while allowing the ceiling surface to be positioned closer to the center for weight reduction.
3Object-affected harmful factors
If the roller contacts the ceiling surface during pitching, then the forcing power is generated causing vibration, but positioning the ceiling surface farther from the center increases outer ring size and weight
Solution Approach 1:
The invention applies dynamics by designing the ceiling surface geometry to enable conditional contact between the roller and ceiling surface. The line shape of the ceiling surface, based on the projected contour of the roller end face, allows contact to occur dynamically when the roller pitches by the predetermined angle or more, generating forcing power to suppress vibration, while maintaining a compact outer ring volume by positioning the ceiling surface closer to the center.
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 suppresses the generation of forcing power when the roller pitches by an angle smaller than the predetermined angle, allowing the ceiling surface to be positioned closer to the center of the outer ring, thus reducing the size and weight of the outer ring and the entire universal joint.
Implementation Method 1
rollers externally fitted onto the tripod shaft portions and configured to roll in the raceway grooves
Implementation Method 2
when the roller comes into contact with the ceiling surface of the raceway groove of the outer ring during pitching, friction is generated due to the contact. This friction causes a forcing power that induces vibration
Data Source
AI summary
A groove-orthogonal sectional shape of a ceiling surface of a raceway groove of an outer ring of a tripod type constant velocity universal joint is a line shape including at least part of a target contour line located away from a central axis of the outer ring in a contour line obtained by projecting a roller end face in an axial direction of the outer ring when a roller pitches by a predetermined angle.