Constant Velocity Joint Ball Tracks for Articulation Angle Control

Solution Overview

Problem

Constant velocity joints face challenges in minimizing reaction forces and ensuring reliable operation across various angular positions, particularly at small and large articulation angles, which affects torque transmission efficiency and ball cage control.

Innovation Solution

A constant velocity joint design featuring outer and inner ball tracks with specific curvature profiles and a ball cage configuration that ensures increasing opening angles within a central articulation range, maintaining reliable cage control and torque transmission capacity, even at large articulation angles, by optimizing the rate of opening angle increase and track curvature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the track curvature in the inner joint part is increased (larger radius of curvature), then the opening angle increases, but the ball cage control becomes unreliable at small articulation angles

Engineering Contradiction:

Improveopening angleVSAvoidball cage control

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The ball track is divided into multiple segments with different curvature radii: a first segment with a smaller radius of curvature for reliable cage control at small articulation angles, and a second segment with a larger radius of curvature for sufficient torque transmission at large articulation angles. This segmentation allows each segment to optimize for its specific operational range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the ball track are given different local geometric properties (curvature radii) to satisfy different functional requirements at different locations along the track path. The first segment has tighter curvature for cage control, while the second segment has gentler curvature for torque capacity.

Inventive Principle:

Principle #3Local quality

2Reliability

If the track curvature in the inner joint part is decreased (smaller radius of curvature), then the ball cage control is improved, but the torque transmission capacity decreases at large articulation angles

Engineering Contradiction:

Improveball cage controlVSAvoidtorque transmission capacity

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The ball track is divided into multiple segments with different curvature radii: a first segment with a smaller radius of curvature for reliable cage control at small articulation angles, and a second segment with a larger radius of curvature for sufficient torque transmission at large articulation angles. This segmentation allows each segment to optimize for its specific operational range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the ball track are given different local geometric properties (curvature radii) to satisfy different functional requirements at different locations along the track path. The first segment has tighter curvature for cage control, while the second segment has gentler curvature for torque capacity.

Inventive Principle:

Principle #3Local quality

3Reliability

If the opening angle is increased to improve cage control, then the reaction forces increase leading to higher power losses

Engineering Contradiction:

Improvecage controlVSAvoidpower losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The ball track is divided into multiple segments with different curvature radii: a first segment with a smaller radius of curvature for reliable cage control at small articulation angles, and a second segment with a larger radius of curvature for sufficient torque transmission at large articulation angles. This segmentation allows each segment to optimize for its specific operational range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The curvature radius parameter of the ball track is changed along its length, transitioning from a smaller radius in the first segment to a larger radius in the second segment. This parameter variation allows optimization of both cage control and power loss characteristics across different articulation angles.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11796008B2Constant velocity joint

Publication Date: 2023.10.24 GKN DRIVELINE INT GMBH

AI summary

A constant velocity joint comprises an outer joint part with outer ball tracks, an inner joint part with inner ball tracks, wherein respectively an outer ball track and an inner ball track form a pair of tracks with each other; a torque-transmitting ball in each pair of tracks; a ball cage in which the torque-transmitting balls are received; wherein a first articulation angle range is defined comprising articulation angles of less than twenty degrees, and a second articulation angle range comprising articulation angles greater than twenty degrees; wherein an opening angle within the first articulation angle range increases as the articulation angle (β) increases, and wherein a first mean opening angle increase of the first articulation angle range is greater than a second mean opening angle increase of the second articulation angle range.