Wheelend Seal Reduces Axial Installation Resistance

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Solution Overview

Problem

Conventional wheelend assembly seals exhibit significant axial resistance during installation, making it difficult to install unitized wheelend assemblies and are prone to early failure without lubricant.

Innovation Solution

A seal device with a wear ring and dynamic seal structure, featuring a resilient member with a support ridge and axially extending portion, along with a gap and support pads, reduces installation forces and enhances sealing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional seal device with wear sleeve is used, then sealing function is provided, but significant axial resistance is generated during installation

Engineering Contradiction:
Improvesealing functionVSAvoidaxial installation resistance
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The wear ring is divided into two separate components: a stationary wear ring attached to the hub and a rotating wear ring attached to the seal assembly. This segmentation allows the seal to rotate with the hub while the stationary wear ring provides a fixed sealing surface, reducing friction and axial resistance during installation and operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The seal assembly is designed to rotate dynamically with the hub rather than remaining stationary. The rotating seal with its associated wear ring moves together with the hub rotation, while the stationary wear ring on the hub provides a fixed counter-surface. This dynamic configuration reduces sliding friction compared to conventional stationary seals.

Inventive Principle:
Principle #15Dynamics

2Reliability

If interference fit and multiple beads are used to facilitate sealing, then sealing performance is improved, but installation and removal forces increase

Engineering Contradiction:
Improvesealing performanceVSAvoidinstallation and removal force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The sealing function is distributed across multiple components including the resilient member, stationary wear ring, rotating wear ring, and seal ribs rather than relying on a single interference-fit structure. This segmentation allows effective sealing through distributed contact pressures while reducing the concentrated installation forces required for interference fits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The seal uses a resilient member that can deform elastically to accommodate the interface between the hub and seal assembly. This elasticity allows the seal to conform to surface variations and maintain sealing pressure without requiring high installation forces, and facilitates easier removal compared to rigid interference-fit structures.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If lubricant is applied during installation, then installation is facilitated, but early failure occurs without proper lubrication

Engineering Contradiction:
Improveinstallation easeVSAvoiddurability without lubricant
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The seal assembly includes integrated lubricant retention features such as lubricant grooves in the wear rings and seal ribs that capture and retain lubricant at the sealing interface. This self-service design ensures continuous lubrication during operation without requiring external lubricant application, preventing early failure while reducing installation 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 seal device facilitates easier installation and improves durability by reducing axial resistance and the need for lubricant, while maintaining effective sealing capabilities.

Implementation Method 1

A molded elastomeric seal structure is substantially coextensive with the interior surfaces of the axially extending portion and the radially, inwardly depending portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The seal structure further includes a seal surface that seals with the surface of the spindle shaft

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3638931B1Wheelend assembly seal
Publication Date: 2022.08.03 STEMCO PRODUCTS INC
  • EP3638931B1 patent drawingFigure 1
  • EP3638931B1 patent drawingFigure 2
  • EP3638931B1 patent drawingFigure 3

AI summary

A wheelend assembly seal between the hub of a wheelend and a spindle shaft is provided. The wheelend assembly seal is a seal device having at least a static seal structure, a wear ring, and a dynamic seal structure. The dynamic seal structure comprises a resilient member that is biased such that in an uninstalled state, the resilient member diverges from an axially extending portion of the dynamic seal structure. When installed, the resilient member is compressed to be approximately parallel the axially extending portion and forms a seal between the surface of the resilient member and the outer surface of the spindle shaft.