Fixed Type Constant Velocity Joint Ball Guide Offset Design

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Solution Overview

Problem

Conventional fixed type constant velocity joints face challenges in enhancing the strength and durability of the cage web area due to limitations in design, particularly when applied to joints with more than six balls, leading to increased size and weight, which is disadvantageous for compact automotive applications.

Innovation Solution

The implementation of differentiated offset configurations in the ball groove shapes, where smaller offsets are applied to tracks with larger ball movements and larger offsets to those with smaller movements, effectively reducing maximum ball movement and increasing the cage web area thickness, thereby enhancing strength and durability without compromising joint size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the number of torque-transmitting balls is increased to eight or ten, then the torque transmission capability is improved, but the cage web area is reduced and the structure becomes more complex

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidcage structure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The invention divides the single uniform offset value into multiple offset values corresponding to different ball positions. The guide grooves are segmented into first guide grooves with a first offset and second guide grooves with a second offset, allowing differentiated control of ball movements to accommodate more balls without proportionally increasing cage complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different offset values are assigned to different local positions of the guide grooves based on their angular positions. This local differentiation optimizes the cage web area distribution, ensuring that regions with higher stress or greater ball movement have appropriate offset values, thereby supporting more balls while maintaining structural integrity

Inventive Principle:
Principle #3Local quality

2Strength

If the cage web area is increased to enhance strength and durability, then the joint size and weight increase, but compact automotive applications require smaller dimensions

Engineering Contradiction:
Improvecage web strengthVSAvoidjoint weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The invention changes the offset parameter of the guide grooves from a uniform value to multiple differentiated values. By adjusting these offset parameters based on angular position, the cage web area is optimized to provide necessary strength and durability without requiring a proportional increase in overall joint size and weight

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If uniform offset values are used for all guide grooves, then the manufacturing is simplified, but the cage web area is not optimized for enhanced strength and durability

Engineering Contradiction:
Improvegroove manufacturing simplicityVSAvoidcage web strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Instead of uniform offset values, the invention implements local quality by assigning different offset values to guide grooves at different angular positions. This allows the cage web area to be optimized for strength and durability in critical regions while maintaining reasonable manufacturing complexity through a systematic differentiation approach

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2609343B1Fixed type constant velocity joint
Publication Date: 2017.05.10 HYUNDAI WIA CORP
  • EP2609343B1 patent drawingFigure 1~2
  • EP2609343B1 patent drawingFigure 3~4
  • EP2609343B1 patent drawingFigure 5~6

AI summary

The ball guide tracks include first tracks and second tracks with different groove configurations and having dual, multiple, or differentiated center offsets with smaller offsets applied to the tracks having relatively large ball movements and larger offsets applied to the tracks having relatively small ball movements as the joint is articulated for assembling.