CV Joint Boot Retention Structure for Durable Hub Sealing

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Solution Overview

Problem

Existing constant velocity joints with integrally formed wheel hubs face challenges in securing a firmly coupled boot state and maintaining effective sealing, leading to durability issues and potential foreign substance penetration.

Innovation Solution

A constant velocity joint design featuring an axle housing with a radially extended portion that presses an inner race of the hub bearing, coupled with a boot that forms a restraining force through a band, ensuring secure assembly and sealing by optimizing the dimensions and geometry of the protrusions and contact portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the boot is coupled to the extension portion without additional fastening structures, then the assembly is simple, but the boot cannot be firmly coupled and sealing function deteriorates

Engineering Contradiction:

Improveassembly simplicityVSAvoidboot coupling firmness

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The boot is divided into multiple contact portions (first, second, third contact portions) that engage with different features of the extension portion and protrusion at different locations, creating multiple discrete coupling points that collectively secure the boot firmly while maintaining assembly simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The boot is inserted over the extension portion and protrusion in a nested configuration, where the boot encompasses these features and forms a restraining force through the band structure, achieving firm coupling without complex fastening mechanisms

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of operation

If the boot is loosely coupled to the extension portion, then assembly is easy, but foreign substances can penetrate and durability decreases

Engineering Contradiction:

Improveassembly easeVSAvoidforeign substance penetration

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The boot functions as a flexible protective shell that surrounds the extension portion and protrusion, creating a sealing barrier that prevents foreign substance penetration while maintaining ease of assembly through its flexible nature that allows it to be stretched and fitted over the features

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The protrusion features a curved outer surface with inclined portions that work with the corresponding contact portions of the boot to create a tapered engagement, allowing the boot to be easily stretched over during assembly while ensuring a tight seal that prevents foreign substance penetration

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If the extension portion has a large protrusion to secure the boot, then boot coupling is firm, but the structure becomes complex and assembly difficulty increases

Engineering Contradiction:

Improveboot coupling firmnessVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The extension portion serves multiple functions: it provides structural support, creates the protrusion for boot engagement, and forms the band fastening groove all in one integrated feature, reducing overall structural complexity while ensuring firm boot coupling

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The band fastening groove is integrated directly into the extension portion structure rather than being a separate feature, merging the fastening mechanism with the structural element to reduce complexity while maintaining firm boot coupling

Inventive Principle:

Principle #5Merging (Combining)

4Ease of operation

If the band is positioned far from the extension portion end, then the boot can be easily assembled, but the sealing function is compromised

Engineering Contradiction:

Improveboot assembly easeVSAvoidsealing function

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The band is pre-positioned at an optimized location on the extension portion that balances assembly ease with sealing effectiveness, allowing the boot to be easily assembled while ensuring the band is positioned to maintain proper sealing function

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11773912B2Constant velocity joint for vehicle

Publication Date: 2023.10.03 HYUNDAI MOTOR CO LTD

AI summary

A constant velocity joint for a vehicle. The constant velocity joint includes: an axle housing fixed to a knuckle by a hub bearing, and a joint assembly inserted into the axle housing to transmit power from a shaft to the axle housing through a plurality of joint balls. In particular, the axle housing includes an extension portion which is extended from an end portion of the axle housing in a radial direction of the axle housing, and the extension portion provides a pressing force to an inner race of the hub bearing in an axial direction of the axle housing. The constant velocity joint further includes a boot surrounding an outer side of the extension portion and coupled to the extension portion so as to form a restraining force between the extension portion and the boot in the axial direction.