Fixed-Type CVJ Geometry Optimization for Larger Operating Angles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fixed-type constant velocity universal joints face challenges in increasing operating angle without compromising strength and durability, particularly due to limitations in outer joint member diameter and increased load on cage pockets as taper angles are increased.
Innovation Solution
Optimizing internal dimensions, including taper angles of track grooves and cage geometry, with specific ratios for outer and inner joint members and cage dimensions to allow for a larger operating angle while maintaining strength and durability, such as taper angles up to 12° and specific ratios for cage dimensions like Do/d, t/d, and w/d, and incorporating features like filleted edges and extended cage surfaces to prevent stress and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the taper angle of track grooves is increased to achieve larger operating angle, then the operating angle is improved, but the wall thickness of outer joint member decreases resulting in decreased strength
Solution Approach 1:
The patent applies parameter changes by optimizing the taper angle of track grooves to a specific range (6° to 12°) and defining precise dimensional relationships between components. By changing these geometric parameters and their ratios, the joint achieves larger operating angles while maintaining adequate wall thickness and strength of the outer joint member.
2Adaptability or versatility
If the taper angle of track grooves is increased to achieve larger operating angle, then the operating angle is improved, but the load exerted upon the cage pocket increases
Solution Approach 1:
The patent reduces the load on cage pockets by optimizing the taper angle within a specific range (6° to 12°) and establishing precise dimensional ratios between the cage, balls, and joint members. These parameter changes ensure that the cage pocket load remains manageable even at larger operating angles.
Solution Approach 2:
The patent applies partial action by using a moderate taper angle (not excessive) within the optimized range of 6° to 12°. This partial optimization of the taper angle achieves sufficient operating angle increase while preventing excessive load on the cage pockets.
3Weight of moving object
If the outer diameter of outer joint member is limited for lightweight and compact joints, then the weight and size are reduced, but the wall thickness decreases when taper angle is increased
Solution Approach 1:
The patent resolves this contradiction by changing the geometric parameters - specifically optimizing the taper angle to 6°-12° and defining precise dimensional ratios. This allows the outer joint member to maintain adequate wall thickness and strength even with limited outer diameter, enabling lightweight and compact joint design.
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
Enables a larger operating angle for front wheels, reducing steering radius, and ensuring the strength and durability of the joint, while minimizing heat generation and maintaining torque transmission efficiency.
Implementation Method 1
a plurality of balls received in the respective track grooves of the outer and inner joint members so as to transmit torque
Data Source
AI summary
Internal dimensions for fixed-type constant velocity universal joints are defined to optimize the geometry of the components of the joints and to readily achieve a larger operating angle of the joints.In the joint, the track grooves of an outer ring and an inner ring are tapered by an angle not exceeding 12°. The ratio (f/PCR) of the cage offset amount f to PCR is greater than 0 and smaller than or equal to 0.12. The ratio (Do/d) of the cage outer diameter (Do) to the ball diameter (d), the ratio (t/d) of the cage wall thickness (t) to the ball diameter (d), and the ratio (w/d) of the cage width (w) to the ball diameter (d) are such that 3.9≦Do/d≦4.1, 0.31≦t/d≦0.34, and 1.8≦w/d≦2.0, respectively. The end of the spherical outer surface of the cage adjacent to the open end is axially extended, and the end of the spherical inner surface of the cage adjacent to the open end is tapered so that the tapered surface has an increasing diameter toward the end of the spherical outer surface adjacent to the open end. Part of the spherical outer surface of the cage is cut on the open end side of pockets, and the outer diameter of the cage across the two opposing planer cut faces is smaller than the spigot diameter of the outer ring.