Spline CV Joint Sleeve Geometry for Strength and Axial Travel

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing constant velocity joints used in off-road vehicles face issues with reduced structural strength and limited pivoting movement, making them prone to damage under the stresses of varied terrains, and require improved assembly and disassembly processes for quick repair.

Innovation Solution

A constant velocity joint design featuring a star-shaped sleeve with a splined connection and a retaining ring system, including transition and ramp chamfer surfaces, for easy assembly and disassembly, enhancing structural strength and allowing for greater angular articulation while maintaining lengthwise adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a cylindrical CV joint is used to allow lengthwise movement, then the joint can adjust for wheel run-out during suspension movement, but the structural strength is reduced compared to a spherical CV joint

Engineering Contradiction:

Improvelengthwise movement capabilityVSAvoidstructural strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The CV joint is divided into modular components including a star-shaped sleeve with splines, a retaining ring, and chamfer surfaces. This segmentation allows the joint to maintain structural integrity through precise geometric features while enabling lengthwise movement through the spline interface between the sleeve and shaft.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention employs asymmetric geometric features including the star-shaped sleeve configuration, splined connection profile, and specifically the transition chamfer surface followed by a ramp chamfer surface. This asymmetry creates a ratcheting effect that permits axial movement in one direction while maintaining structural strength and preventing reverse movement that could compromise joint integrity.

Inventive Principle:

Principle #4Asymmetry

2Adaptability or versatility

If a cylindrical CV joint is used to permit lengthwise movement, then the joint can accommodate suspension travel, but the maximum amount of pivoting movement is reduced due to interference between the shaft and shell at high angles

Engineering Contradiction:

Improvelengthwise movement capabilityVSAvoidpivoting movement range

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #4Asymmetry

3Ease of manufacture

If a retaining ring is used to retain the star-shaped sleeve on the shaft, then the assembly process can be simplified, but the disassembly process becomes difficult without proper tools and procedures

Engineering Contradiction:

Improveassembly simplicityVSAvoiddisassembly difficulty

Core Design Contradiction:

Ease of manufactureVSEase of repair

Solution Approach 1:

The star-shaped sleeve incorporates pre-formed chamfer surfaces (transition chamfer and ramp chamfer) that perform the preliminary action of guiding and compressing the retaining ring during assembly. These pre-designed geometric features automatically center and seat the retaining ring in the groove, eliminating the need for additional assembly tools or steps while also facilitating controlled disassembly through the same features.

Inventive Principle:

Principle #10Preliminary action

4Ease of operation

If the star-shaped sleeve is designed with multiple chamfer surfaces for easy assembly and disassembly, then the manufacturing complexity increases, but the overall assembly process is significantly simplified

Engineering Contradiction:

Improveassembly and disassembly easeVSAvoidsleeve geometric complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Multiple functional features (centering, compression, guiding, and retention) are merged into a single integrated retaining ring component that interacts with the chamfer surfaces of the star-shaped sleeve. This merging eliminates the need for separate assembly tools, multiple retention components, or complex assembly procedures, as the chamfered geometry performs multiple functions simultaneously during both assembly and disassembly operations.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11242896B2Spline slip constant velocity joint

Publication Date: 2022.02.08 ZHEJIANG CFMOTO POWER CO LTD

AI summary

A constant velocity ball joint uses a star shaped sleeve with a splined connection to its shaft. The sleeve is longitudinally retained on its shaft using a retaining ring in an outwardly facing groove of the shaft. The star shaped sleeve has a 30° assembly assist chamfer angle on one side, as well as a 45° transition chamfer angle and a 65° ramp chamfer angle facing the opposite direction. These angles control the diameter of the retaining ring as it is compressed inward into the groove during assembly and disassembly. The star shaped sleeve can be used in a dynamic length CV joint, with the splines of a configuration that allows longitudinal sliding of the sleeve on the shaft, so the shell of the dynamic length CV joint still can be of the spherical race type.