CVJ Assembly with Pre-installed Elastomeric Boot Seal
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Solution Overview
Problem
Existing motor vehicle powertrain systems face challenges in achieving fast, reliable, and cost-effective assembly of components, particularly in attaching an output shaft to a constant velocity joint (CVJ) component, which affects the overall quality and reliability of the system.
Innovation Solution
The powertrain assembly features a CVJ assembly with a tubular section friction welded to a hollow propeller shaft tube, incorporating a seal assembly with an elastomeric boot and sheet metal cap for sealing, and a circlip mechanism for secure alignment and locking of the output shaft, allowing for straightforward and reliable assembly without additional orientation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional assembly methods are used for attaching output shaft to CVJ, then assembly reliability can be maintained, but assembly time and complexity increase
Solution Approach 1:
The seal assembly is pre-installed on the output shaft before the CVJ assembly process. The elastomeric boot is positioned and secured with the retaining ring in advance, so that when the output shaft is inserted into the CVJ, the sealing is already in place without requiring additional orientation or adjustment steps during final assembly.
Solution Approach 2:
The seal assembly is integrated directly with the output shaft as a combined unit. The elastomeric boot, retaining ring, and shaft form a pre-assembled subsystem that is inserted as one piece, reducing the number of separate components and assembly operations required.
2Productivity
If simple assembly processes are used, then assembly speed increases, but assembly precision and reliability decrease
Solution Approach 1:
The elastomeric boot is designed with an asymmetric cross-sectional shape that provides a tapered profile. This asymmetric geometry creates a self-aligning feature where the boot naturally orients itself correctly during insertion into the CVJ assembly, ensuring proper sealing position without requiring additional orientation steps by the assembler.
Solution Approach 2:
The retaining ring is designed to automatically secure the elastomeric boot to the output shaft through its interference fit and deformation characteristics. The ring self-locks the boot in place during the assembly process without requiring additional fastening operations or tools, ensuring precise positioning through the material's own elastic properties.
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 design enhances the assembly process by ensuring accurate and reliable attachment of the output shaft to the CVJ, reducing noise and vibration, while providing cost benefits and improved reliability through a simplified assembly process.
Implementation Method 1
As the output shaft is plugged in, the boot inner lip is forced to expand, as the inside cylindrical surface is slid onto the shaft section
Implementation Method 2
tubular section friction welded to hollow propeller shaft tube
Data Source
AI summary
A powertrain assembly for use in a motor vehicle powertrain system having an output shaft forming a cylindrical outer surface, a splined end, and a radial shoulder, and a CVJ assembly having an inner race, and outer race. Ball elements are provided between the inner and outer races. A seal assembly is provided having a boot with an outer lip affixed to the CVJ outer race and an inner lip forming first and second radial faces and an inside cylindrical surface. Axial insertion of the output shaft splined end into the CVJ inner race splined bore causes the boot assembly inner lip to be expanded and frictionally engage with the output shaft cylindrical outer surface and wherein the boot inner lip first and second radial faces are clamped between the inner race radial surface and the shaft radial shoulder.