Constant Velocity Joint Shaft Assembly Venting Design

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Solution Overview

Problem

Existing shaft assemblies for venting pressurized gases from constant velocity joints either result in excessive lubricant loss or inadequate contaminant protection, failing to provide efficient and robust venting solutions.

Innovation Solution

A shaft assembly design featuring a first and second annular crest separated by an inclined surface, with a boot secured between them, including a channel and diaphragm portion for efficient venting of pressurized gases while minimizing lubricant loss and preventing contaminant entry, utilizing a boot band assembly for secure attachment and a channel that turns about the longitudinal axis to ensure oblique inlet and outlet portions for effective pressure relief.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing venting assemblies are used to vent pressurized gases from constant velocity joints, then pressure relief is achieved, but lubricant loss increases and contaminant protection is insufficient

Engineering Contradiction:
Improveventing efficiencyVSAvoidlubricant loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The boot assembly uses a flexible boot material that forms a sealed enclosure around the constant velocity joint, with integrated diaphragm portions that flex to allow pressure equalization while maintaining containment. The flexible nature of the boot allows it to accommodate joint movement while preventing lubricant escape and contaminant ingress, except through controlled vent channels.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The vent channel acts as an intermediary pathway that allows pressurized gases to escape while preventing direct communication between the sealed boot interior and the external environment. The channel is positioned and configured to permit gas flow while blocking lubricant and contaminant passage, serving as a selective mediator between the internal and external environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If existing venting assemblies are used to vent pressurized gases, then pressure relief is achieved, but contaminant protection is insufficient

Engineering Contradiction:
Improveventing efficiencyVSAvoidcontaminant entry
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The boot assembly uses a flexible boot material that forms a sealed enclosure around the constant velocity joint, with integrated diaphragm portions that flex to allow pressure equalization while maintaining containment. The flexible nature of the boot allows it to accommodate joint movement while preventing lubricant escape and contaminant ingress, except through controlled vent channels.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The vent channel acts as an intermediary pathway that allows pressurized gases to escape while preventing direct communication between the sealed boot interior and the external environment. The channel is positioned and configured to permit gas flow while blocking lubricant and contaminant passage, serving as a selective mediator between the internal and external environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a sealed boot is used to protect the constant velocity joint, then contaminant protection is improved, but pressurized gas venting is insufficient

Engineering Contradiction:
Improvecontaminant protectionVSAvoidpressure relief
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The boot assembly uses a flexible boot material that forms a sealed enclosure around the constant velocity joint, with integrated diaphragm portions that flex to allow pressure equalization while maintaining containment. The flexible nature of the boot allows it to accommodate joint movement while preventing lubricant escape and contaminant ingress, except through controlled vent channels.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The vent channel acts as an intermediary pathway that allows pressurized gases to escape while preventing direct communication between the sealed boot interior and the external environment. The channel is positioned and configured to permit gas flow while blocking lubricant and contaminant passage, serving as a selective mediator between the internal and external environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The design effectively vents pressurized gases to the atmosphere while minimizing lubricant loss and protecting the constant velocity joint from contaminants, offering improved robustness and efficiency in pressure equalization.

Implementation Method 1

a shaft assembly which allows pressurized gases from a constant velocity joint to be vented

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

The channel comprises an inlet portion, a partially helical portion, and an outlet portion formed in an inner surface of the boot

Methodology Applied
Scientific EffectHelical flow: Vortex Ring

Data Source

PatentEP2825786B1Shaft assembly for a constant velocity joint
Publication Date: 2019.05.08 DANA AUTOMOTIVE SYST GRP LLC
  • EP2825786B1 patent drawingFigure 1
  • EP2825786B1 patent drawingFigure 1A
  • EP2825786B1 patent drawingFigure 2~3

AI summary

A shaft assembly (10) is provided. The shaft assembly includes a first shaft (12). The first shaft has a first annular crest (20) and a second annular crest (22). The first annular crest and the second annular crest are separated by an inclined surface (32). The second annular crest includes an axially extending surface (28) attached to an end of the inclined surface. A boot (52) is secured to the shaft. The boot includes a channel (102) and a diaphragm portion (90) disposed adjacent an end of the channel. The channel includes an inlet portion (104), a partially helical portion (106), and an outlet portion (108) formed in an inner surface of the boot. The diaphragm portion is provided over the inclined surface and includes a lip (120) which contacts the second annular crest.