Rotary Shaft Sealing Ring With Staggered Lips for Wear Reduction

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Solution Overview

Problem

Existing sealing rings for rotary shafts suffer from decreased pre-load due to aging and wear, especially when misaligned or inaccurately manufactured, leading to increased wear and reduced service life, and require constant additional spring force for contact maintenance.

Innovation Solution

The sealing ring design features lips pointing in the same axial direction, with the first lip surpassing the second lip, allowing for elastic deformation to deflect contaminants and absorb impact, while a support protrusion ensures alignment and lubrication storage, eliminating the need for external springs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate spring element is used to maintain constant pre-load on the sealing ring, then contact between the sealing ring and rotary shaft is maintained, but device complexity increases and wear increases due to constant increased pre-load

Engineering Contradiction:
Improveconstant contact maintenanceVSAvoidseparate spring element
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring element is integrated into the sealing ring structure itself, merging the sealing function and the spring loading function into a single component. This eliminates the need for a separate spring element while maintaining constant pre-load on the sealing lip, thereby reducing device complexity while ensuring reliable contact maintenance between the sealing ring and rotary shaft.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If increased spring force is applied to compensate for misalignment and wear, then sealing reliability is improved, but wear increases and service life decreases

Engineering Contradiction:
Improvesealing contactVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The sealing lip is designed with elastic material properties that allow it to dynamically adapt to misalignment and wear conditions. The integrated spring element provides progressive loading that increases pre-load only when needed (when misalignment or wear occurs) rather than applying constant increased force, thereby maintaining sealing reliability while reducing unnecessary wear and extending service life.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing ring uses material parameter changes (elasticity) to compensate for dimensional changes due to wear and misalignment. The elastic material allows the sealing lip to deform and maintain contact pressure despite changes in the rotary shaft position or dimensions, providing adaptive sealing without requiring excessive pre-load that would accelerate wear.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If lips point in different axial directions to optimize for lubricant sealing and contaminant prevention, then sealing effectiveness is improved, but ability to deflect contaminants from multiple directions is reduced

Engineering Contradiction:
Improvesealing effectivenessVSAvoidcontaminant deflection
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing ring features an asymmetric design where the first sealing lip extends further axially than the second sealing lip. This asymmetric configuration creates a staggered arrangement that allows the lips to deflect contaminants approaching from multiple directions while maintaining effective sealing. The longer first lip acts as a primary deflection barrier, while the second lip provides secondary sealing, combining both contaminant deflection and sealing effectiveness.

Inventive Principle:
Principle #4Asymmetry

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 maintains consistent contact with the rotary shaft under harsh conditions, reduces wear, and enhances durability by deflecting contaminants and managing lubrication effectively, thus extending the sealing ring's service life.

Implementation Method 1

the first lip is designed longer in its axial extension than the second lip with the consequence that the first lip is more deformable than the second lip. This leads to the advantage that the outer or first lip may absorb impact and deflect water, dust or debris that is projected from multiple directions from the outside environment onto the sealing ring.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4261439B1Sealing ring for radially engaging an outer surface of a rotary shaft
Publication Date: 2025.08.27 ROBERT BOSCH GMBH
  • EP4261439B1 patent drawingFigure 1~3
  • EP4261439B1 patent drawingFigure 3A~4D
  • EP4261439B1 patent drawingFigure 5

AI summary

The present invention pertains a sealing ring (1) for radially engaging an outer surface of cylindrical element, in particular a rotary shaft (22), the sealing ring (1) comprising a ring base body (2) having a central rotating axis (8), further comprising a first lip (3) and a second lip (4) that each extend from the ring base body (2) to sealingly engage the rotary shaft (22). It is provided that the sealing tips (13, 14) of both sealing lips point at least in part in the same axial direction, and that the first lip (3) surpasses the second lip (4) in axial direction such that the sealing tip (13) of the first lip (3) is arranged axially distanced to the second lip (4).