Constant Velocity Joint Inner Race Locking Without Retaining Ring
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Solution Overview
Problem
Existing constant velocity joint (CVJ) assemblies require a separate retaining ring and complex machining processes, leading to increased manufacturing costs and potential assembly inaccuracies due to tight tolerances and axial lash issues.
Innovation Solution
A constant velocity joint design where the inner race is fixed directly to the shaft without a secondary component, using mechanically upset material to create locking tabs that engage with recesses or grooves on the shaft, eliminating the need for a retaining ring and simplifying the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate retaining ring is used to secure the inner race to the shaft, then the assembly can be retained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The retaining function is merged into the inner race itself by forming integral locking tabs that extend radially inward to engage with recesses in the shaft. This eliminates the separate retaining ring component while maintaining the retention function, directly resolving the contradiction between reliability and device complexity
Solution Approach 2:
The retaining ring component is extracted/removed from the assembly. The retention function is achieved through the locking tabs formed as part of the inner race, eliminating the need for the separate retaining ring and reducing overall device complexity
2Reliability
If ring grooves are machined in both the race and shaft for retaining ring installation, then the retaining ring can be installed, but manufacturing time and cost increase
Solution Approach 1:
The complex ring groove machining operation is extracted/eliminated from the manufacturing process. The locking tabs are formed through a simpler deformation process applied only to the inner race, removing the time-consuming dual-groove machining requirement and improving productivity
Solution Approach 2:
The manufacturing approach changes from machining (subtractive process) to deformation (formative process). The locking tabs are created by plastically deforming the inner race material, which is generally faster and less costly than precision machining grooves in both components
3Manufacturing precision
If tight tolerances are applied to ring groove and retaining ring thickness, then assembly accuracy can be achieved, but manufacturing cost increases
Solution Approach 1:
The tight tolerance requirements are extracted from the design. By eliminating the retaining ring and its associated grooves, the source of tolerance accumulation is removed. The direct interference fit between the locking tabs and shaft recesses provides inherent tolerance compensation, achieving assembly accuracy without costly tight tolerances
Solution Approach 2:
The locking tabs act as an intermediary element that mediates the connection between the inner race and shaft. This intermediate structure provides tolerance absorption and distribution, allowing for less stringent tolerances on individual components while maintaining overall assembly precision
4Reliability
If separate retaining ring and ring grooves are used, then the inner race can be retained, but axial lash between race and shaft occurs
Solution Approach 1:
The retention function is merged directly into the inner race structure through integral locking tabs. This direct integration eliminates the clearance or lash that exists between separate components (retaining ring and grooves), as the locking tabs form a continuous load path from the inner race to the shaft, eliminating axial lash while maintaining retention
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
This solution reduces manufacturing complexity and costs by eliminating the need for additional components and machining processes, while ensuring a secure and precise assembly with improved repeatability and reduced axial lash.
Implementation Method 1
The inner race is fixed to the shaft with mechanically upset material
Data Source
AI summary
A constant velocity joint includes an outer race, an inner race configured for pivotal movement relative to the outer race, and a shaft. The inner race is fixed to the shaft without a secondary component.