Wheel Bearing Inner-Ring Sealing With Flat Contact Faces

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Solution Overview

Problem

Existing wheel bearing units face issues with inadequate sealing, leading to lubricant leakage and contamination by foreign substances, which results in reduced bearing life and increased costs due to the use of expensive sealing components.

Innovation Solution

A wheel bearing unit with a sealing device featuring an annular holding element and a sealing element with flat contact points and insertion bevels, which provides radial contact and self-locking properties, ensuring effective sealing without the need for additional pressure and maintaining performance over the service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sealing rings with metallic clamping elements are used, then sealing function is achieved, but manufacturing cost increases and hermetic sealing is not enabled

Engineering Contradiction:
Improvesealing functionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the metallic clamping element from the sealing ring structure. The sealing ring is designed as a one-piece elastomeric component without any metallic inserts, eliminating the need for complex rubber-metal composite manufacturing processes while maintaining effective sealing through the elastomeric material's inherent properties

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive rubber-metal composite sealing rings with simpler, cheaper all-elastomeric sealing rings. The simplified structure reduces manufacturing complexity and material costs while the elastomeric material provides sufficient sealing performance for the application

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Force

If tapered contact points are used on sealing element, then contact pressure is achieved, but sealing performance deteriorates over time due to folding and position changes

Engineering Contradiction:
Improvecontact pressureVSAvoidsealing performance over service life
Core Design Contradiction:
ForceVSDuration of action of moving object

Solution Approach 1:

Instead of using tapered contact points that converge to a point or line, the invention inverts the geometry to use flat contact surfaces. This reversal prevents the sealing element from folding during axial movements and maintains consistent contact pressure with the inner rings throughout the bearing's operational life

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The flat contact surfaces are designed to accommodate axial movements and position changes of the sealing element in advance. The geometry provides a cushioning effect that maintains sealing contact even when the sealing element shifts axially during operation, preventing loss of sealing performance

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If axial bracing of inner rings is insufficient, then device complexity is reduced, but sealing effectiveness deteriorates allowing foreign substance ingress

Engineering Contradiction:
Improvestructural complexityVSAvoidsealing effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention applies local quality by designing the sealing element with different geometric features at different locations. The flat contact surfaces are positioned to provide axial bracing exactly where needed at the interface with the inner rings, while other portions of the sealing element maintain flexibility for sealing contact, achieving effective sealing without overall structural complexity

Inventive Principle:
Principle #3Local quality

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 provides a hermetically sealing and cost-effective solution that prevents foreign substances and lubricant migration, enhancing the sealing performance and extending the bearing life while reducing material costs.

Implementation Method 1

the sealing element (11) designed in such a way that it has at least two contact points (13, 14) which contact the holding element (10) and at least one contact point (15, 16) which each has one inner ring (3) contacted

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

at least one of the contact points being designed such that it has a flat surface

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4058680B1Wheel bearing unit
Publication Date: 2023.11.08 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4058680B1 patent drawingFigure 1~2
  • EP4058680B1 patent drawingFigure 3~5
  • EP4058680B1 patent drawingFigure 6a~6b

AI summary

The invention relates to a wheel bearing unit having at least one outer ring (4) and at least two inner rings (3), between which there are rolling elements guided in a cage, two adjacent inner rings bearing against each other by their mutually facing axial end faces (6), and a sealing device (8) being provided to seal an interface of the two inner rings, the sealing device being formed by an annular retaining element (10), and at least one sealing element (11) being provided on the retaining element, said sealing element being in the form of a sealing ring (12) which has at least two contact points which are in contact with the retaining element and at least one contact point which is in contact with one inner ring in each case, at least one of the contact points being designed such that it has a flat face.