Hub Cap Vent Plug With Labyrinth Shield for Leak-Free Venting

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Solution Overview

Problem

Existing wheel end assembly vents allow leaks, allowing lubricant to escape and foreign matter to ingress, potentially damaging the assembly.

Innovation Solution

A vent plug system with a cover and base forming a chamber, including a labyrinth path and a shield that inhibits liquid ingress while allowing gas to vent, featuring a valve that opens when pressure exceeds a threshold, ensuring pressure equalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a vent path is provided to allow pressure equalization between the cavity and the environment, then pressure equalization is improved, but lubricant leakage and foreign matter ingress occur

Engineering Contradiction:
Improvepressure equalizationVSAvoidlubricant containment and contamination prevention
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The vent plug is segmented into multiple functional components: a vent path for pressure equalization, a shield with labyrinthine features to block lubricant and foreign matter, and a valve mechanism for selective opening/closing. This segmentation allows each component to perform its specific function while collectively resolving the contradiction between pressure equalization and contamination prevention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shield acts as an intermediary element between the vent path and the cavity. It provides a labyrinthine path that mediates between the need for gas venting and the need to block lubricant and foreign matter, allowing gas to pass while preventing harmful substances from entering or escaping.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a labyrinth or tortuous path is provided in the vent path, then lubricant leakage and foreign matter ingress are inhibited, but device complexity increases

Engineering Contradiction:
Improvelubricant containment and contamination preventionVSAvoidvent path structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shield is constructed as a thin, annularly extending disc with labyrinthine features that provides effective contamination prevention without adding significant structural complexity. The simple disc shape with integrated labyrinth features offers an elegant solution that maintains reliability while minimizing device complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a valve is provided to selectively open and close the vent path, then controlled venting is improved, but device complexity increases

Engineering Contradiction:
Improvecontrolled ventingVSAvoidvent plug structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The valve mechanism is designed to operate automatically based on pressure differential across the vent plug. When pressure in the cavity exceeds a predefined threshold, the valve opens to allow venting; when pressure equalizes, the valve closes automatically. This self-service operation provides controlled venting without requiring external control systems, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #25Self-service

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 solution effectively prevents lubricant leakage and foreign matter ingress, maintaining the integrity of the wheel end assembly by allowing controlled gas venting.

Implementation Method 1

The vent path, whether in a plug or not, may provide a labyrinth or tortuous path between the cavity and the environment

Methodology Applied
Scientific EffectLabyrinth path:

Implementation Method 2

when pressure is sufficiently high, to the chamber and eventually atmosphere

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

The valve selectively opens and closes to place the cavity in fluid communication with the chamber

Methodology Applied
Scientific EffectPressure threshold activation:

Data Source

PatentEP3752373B1Vent plug for a hub cap
Publication Date: 2024.11.13 STEMCO PRODUCTS INC
  • EP3752373B1 patent drawingFigure 1
  • EP3752373B1 patent drawingFigure 2
  • EP3752373B1 patent drawingFigure 3~6

AI summary

A vent plug for a hub cap is provided. The vent plug includes a cover and base forming a chamber. A vent plug body extends from the base and forms a cavity. A shield is coupled to the vent plug body. The shield comprises an annularly extending disc that traverses the cavity. The shield includes a connecting surface to connect the shield to the vent plug body. The shield provides a lubrication/liquid barrier to inhibit lubrication (or other liquid) from entering the cavity formed by the vent plug body and the chamber. The connection between the shield and the vent plug body allows a gas (typically air) to vent past the shield into the cavity and, when pressure is sufficiently high, to the chamber and eventually atmosphere.