Protective Ring Engagement Structure for Stable Seal Positioning

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Solution Overview

Problem

In conventional sealing devices with protective rings, a greater-than-expected external force can cause the protective ring to displace from its predetermined position.

Innovation Solution

The sealing device incorporates an engagement portion on the protective ring that engages with the inner peripheral surface of the gasket portion, featuring an upstanding wall portion that bites into the surface when a force is applied, preventing displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the protective ring is held only by repulsive force of squashed elastic portion, then the structure is simple, but the protective ring may displace when greater-than-expected external force is applied

Engineering Contradiction:
Improvestructure simplicityVSAvoidprotective ring position stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The holding mechanism is divided into two independent parts: (1) the repulsive force from the squashed elastic portion providing initial retention, and (2) the engagement portion with upstanding wall portion providing mechanical interlocking. This segmentation allows each part to perform its specific function optimally while together they ensure both simplicity and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines two different retention mechanisms - the elastic repulsive force and the mechanical engagement through the upstanding wall portion - into a unified holding system. This merging ensures that the protective ring is retained under normal conditions by the elastic force alone, while under exceptional external forces, the engagement portion provides additional mechanical restraint.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If an engagement portion with upstanding wall portion is added to prevent displacement, then position stability is improved, but device complexity increases

Engineering Contradiction:
Improveprotective ring position stabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The engagement portion is designed with local quality - the upstanding wall portion is positioned specifically at the location where it can engage with the reinforcement ring tubular portion. This localized feature provides the necessary mechanical engagement only where needed, rather than complicating the entire protective ring structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of making the protective ring completely rigid to prevent displacement, the patent uses a compliant elastic portion that deforms under normal conditions but engages mechanically when needed. The upstanding wall portion is designed to bend or deform elastically, allowing the ring to adapt to installation conditions while maintaining position stability under load.

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

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

This configuration effectively suppresses the displacement of the protective ring, ensuring it remains in its intended position even under external forces.

Implementation Method 1

The protective ring is held on the inner periphery side of the tubular portion with a repulsive force (i.e., a frictional force) of rubber generated as the elastic portion provided on the inner periphery side of the tubular portion is squashed.

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

an elastic portion (30) around an axis x that is formed of an elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4027041B1Sealing device
Publication Date: 2025.05.14 NOK CORP
  • EP4027041B1 patent drawingFigure 1~2
  • EP4027041B1 patent drawingFigure 3

AI summary

Provided is a sealing device that can suppress the displacement of a protective ring. A sealing device (1) includes an annular reinforcement ring (20) around an axis x; an annular elastic portion (30) around the axis x that is attached to the reinforcement ring (20), is formed of an elastic material, and includes a lip portion (35); and an annular protective ring (40) around the axis x that is adapted to be fitted to an inner periphery side d the reinforcement ring (20). The reinforcement ring (20) includes a reinforcement ring tubular portion (21) formed in a tubular shape around the axis x. The protective ring (40) includes a protective ring tubular portion (41) formed in a tubular shape around the axis x, and an engagement portion (43) that is provided on an outer peripheral surface (411) of the protective ring tubular portion (41) and is adapted to engage with the inner periphery side d of the reinforcement ring (20).