Constant-Velocity Joint Groove Layout for Heat and Impact Control
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Solution Overview
Problem
The fixed type constant velocity universal joints face challenges in absorbing impact loads due to high axial strength and spherical-surface contact, which leads to increased impact force during vehicle crashes, as the cage is unable to move within the joint, causing the propeller shaft to stiffen.
Innovation Solution
The design features track grooves with zero offset, forming wedge angles in alternate directions, reducing axial strength on the deep side and increasing it on the inlet side, allowing the cage to stabilize at the joint's bisecting plane, and reducing spherical-surface contact, enabling the joint to absorb impact by allowing the cage to slip and break on the weaker side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the fixed type constant velocity universal joint uses spherical-surface contact between the cage and outer joint member, then the joint maintains high axial strength and stability, but the propeller shaft stiffens during impact and increases impact force on the vehicle
Solution Approach 1:
The invention applies different surface geometries to different regions of the outer joint member. The deep side (joint inlet side) uses a cylindrical surface instead of spherical surface, while the inlet side (joint deep side) maintains spherical surface contact. This local differentiation allows the cage to slip on the cylindrical surface during impact, reducing impact force, while maintaining stability through spherical contact on the other side.
2Temperature
If the track grooves have zero offset and form wedge angles in alternate directions, then the cage stabilizes at the joint's bisecting plane and heat generation is reduced, but the joint cannot absorb impact loads effectively
Solution Approach 1:
The invention combines zero-offset track grooves for heat reduction with a localized cylindrical surface on the deep side. The zero-offset alternating wedge angles stabilize the cage at the bisecting plane, reducing friction and heat generation. Simultaneously, the cylindrical surface on the deep side allows controlled slippage during impact, enabling impact absorption without compromising the thermal benefits.
3Stability of the object's composition
If the cage is constrained to prevent slippage, then the joint maintains fixed type stability, but the propeller shaft cannot absorb impact and transmits full force to the vehicle
Solution Approach 1:
The invention creates a dual-nature joint by applying cylindrical surface on the deep side and spherical surface on the inlet side. The cylindrical region permits controlled slippage for impact absorption, while the spherical region maintains stability. This local differentiation allows the joint to exhibit both fixed-type stability and impact-absorbing capability simultaneously.
Solution Approach 2:
The invention segments the outer joint member's inner surface into two distinct regions: a cylindrical surface on the deep side and a spherical surface on the inlet side. This segmentation allows different functional behaviors in different regions - slippage on the cylindrical side for impact absorption and stable contact on the spherical side for maintaining joint integrity.
Data Source
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AI summary
Provided is a fixed type constant velocity universal joint capable of suppressing heat generation under high load and during high-speed rotation to improve durability, and suppressing a contact resistance between a cage and inner and outer joint members to improve the constant velocityproperty. An axial offset amount of a curvature center of each track groove (22) of an outer joint member (23) and an axial offset amount of a curvature center of each track groove (25) of an inner joint member (26) are zero. Track grooves (22a, 22b) of the outer joint member (23) are formed alternately in a circumferential direction to be inclined in mutually opposite directions with respect to an axis, and track grooves (25a, 25b) of the inner joint member (26) are formed alternately in the circumferential direction to be inclined in mutually opposite directions with respect to the axis. An outer surface (24) of the inner joint member (26) is formed into a spherical surface (21b) which is held in slide-contact with an inner spherical surface (28b) of a cage (28). An inner surface (21) of the outer joint member (23) is formed into a cylindrical surface (21a).