Heavy-Duty Wheel End Seal Lip Segmentation for Drag Reduction

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Solution Overview

Problem

Existing wheel end assemblies for heavy-duty vehicles face challenges in preventing contaminants from entering while retaining lubricant and minimizing drag, leading to reduced seal life and fuel efficiency.

Innovation Solution

A main seal design featuring a dynamic portion seating in a wheel hub bore and a static portion on the axle spindle, with elastomeric lips and internal features like a capillary surface and pumping surface to expel contaminants, while maintaining minimal drag and optimizing fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If contact-type seals are used to prevent contaminants from entering the wheel end assembly, then contaminant exclusion is improved, but drag increases reducing seal life and fuel efficiency

Engineering Contradiction:
Improvecontaminant exclusionVSAvoiddrag
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The seal is divided into multiple functional lips (first lip, second lip, third lip) with distinct responsibilities. The first lip provides primary sealing contact, the second lip enhances contaminant exclusion, and the third lip provides additional sealing. This segmentation allows each lip to be optimized for its specific function, achieving superior contaminant exclusion while minimizing overall drag through selective contact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the seal have different contact characteristics. The first lip is designed to contact the rotating hub surface for primary sealing, while the second and third lips are positioned and configured to provide enhanced contaminant exclusion with minimal contact. This local differentiation of contact properties allows the seal to achieve superior contaminant exclusion while minimizing overall drag.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If non-contact seals are used to minimize drag, then fuel efficiency is improved, but contaminant exclusion capability deteriorates

Engineering Contradiction:
ImprovedragVSAvoidcontaminant exclusion
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The seal incorporates a hybrid contact-dynamics design where the first lip maintains light contact with the rotating hub for primary sealing, while the second and third lips operate in a near-non-contact manner to provide enhanced contaminant exclusion. The dynamic configuration allows the seal to adapt between contact and non-contact modes depending on the specific contaminant threat and operational conditions, achieving both low drag and superior contaminant exclusion.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If multiple sealing lips are added to enhance contaminant exclusion, then seal effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvecontaminant exclusionVSAvoidseal structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple sealing lips (first lip, second lip, third lip) are merged into a single integrated seal body formed from a single piece of elastomeric material. This unified structure provides enhanced contaminant exclusion through multiple lips while avoiding the complexity of assembling multiple separate components. The merging of functions into a single monolithic structure simplifies installation and maintenance while achieving superior sealing performance.

Inventive Principle:
Principle #5Merging (Combining)

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 seal effectively prevents contaminants from entering the wheel end assembly, retains lubricant, and extends the seal's life while enhancing fuel efficiency by using a combination of external and internal features that minimize drag and enhance contaminant exclusion.

Implementation Method 1

the elastomeric sealing lip contacts the rotating hub surface... including minimal drag or friction between its internal components

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

A capillary surface and pumping surface are provided which cooperate to dynamically expel contaminants

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

A capillary surface and pumping surface are provided which cooperate to dynamically expel contaminants

Methodology Applied
Scientific EffectFluid dynamics:

Data Source

PatentEP2962018B1Main seal for a heavy-duty vehicle wheel-end assembly
Publication Date: 2019.05.22 HENDRICKSON USA LLC
  • EP2962018B1 patent drawingFigure 1
  • EP2962018B1 patent drawingFigure 2
  • EP2962018B1 patent drawingFigure 3

AI summary

A wheel end assembly for a heavy-duty vehicle includes an axle spindle and a hub rotatably mounted on the axle spindle. A main seal extends radially between the axle spindle and the hub. The seal includes a dynamic portion that seats in a bore formed in the wheel hub, and a static portion that seats on the axle spindle. The static portion includes a rigid carrier that in turn includes a first member, and a second member that is rigidly attached to the first member. An elastomer is bonded to the carrier member and forms a first external lip. The first external lip extends generally parallel to a chamfer formed in an inboard end of the hub. The first external lip, other external features, and internal features prevent contaminants from entering the wheel end assembly, retain lubricant in the assembly, and provide a dynamic expulsion surface to expel contaminants.