Resin Seal Ring Step Surface Design for High-Pressure Gas Sealing

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Solution Overview

Problem

Seal rings made of resin used in high-pressure gas sealing structures experience creep deformation over time, leading to reduced squeeze and compromised sealing function, especially in low-temperature conditions.

Innovation Solution

A sealing structure that maintains close contact with the step surface of the mounting hole, even when the seal ring's squeeze is reduced, by utilizing a resin seal ring with a heat-resistant material and a design that includes a step surface on the inner peripheral surface of the mounting hole, preventing gas leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a resin seal ring is used to suppress vibrations and reduce components, then noise suppression is improved, but the sealing function deteriorates over time due to creep deformation

Engineering Contradiction:
Improvenoise suppressionVSAvoidsealing function
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The seal ring is divided into two distinct functional surfaces: a first peripheral surface for noise suppression and vibration damping, and a second peripheral surface for maintaining sealing contact. This segmentation allows each surface to specialize in its respective function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different surfaces of the seal ring are given different geometric properties tailored to their specific functions. The first peripheral surface has properties optimized for vibration suppression, while the second peripheral surface has properties optimized for maintaining sealing contact pressure, creating local quality variations throughout the component.

Inventive Principle:
Principle #3Local quality

2Temperature

If the seal ring diameter shrinks in low-temperature conditions, then thermal contraction occurs, but a gap forms between the seal ring and mounting hole

Engineering Contradiction:
Improvelow-temperature operationVSAvoidsealing function
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The seal ring is pre-formed with an oval cross-section that is larger in the radial direction than the axial direction. This preliminary geometric configuration ensures that even when thermal contraction occurs at low temperatures, the seal ring maintains sufficient contact with the mounting hole surface, preventing gap formation before the sealing function is needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cross-sectional geometry of the seal ring is specifically designed with different dimensions in different directions (oval rather than circular). This parameter change in the geometric configuration allows the seal ring to compensate for thermal contraction effects and maintain sealing performance across temperature variations.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If the squeeze of the seal ring is reduced over time, then creep deformation occurs, but the sealing function deteriorates

Engineering Contradiction:
Improveservice lifeVSAvoidsealing function
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The seal ring design incorporates dynamic geometric features that adapt to deformation over time. The oval cross-section and specific peripheral surface configurations are designed to maintain effective sealing contact even as the material undergoes creep deformation during extended service life.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing mechanism transitions from relying solely on radial squeeze to utilizing contact with a step surface in the axial direction. By engaging the second peripheral surface with the step surface, the sealing function is maintained through a different dimensional contact mechanism that is less sensitive to radial creep deformation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 sealing structure effectively prevents high-pressure gas leakage even when the seal ring's squeeze is reduced and in low-temperature conditions, ensuring consistent sealing performance.

Implementation Method 1

the seal ring made of resin has a problem that a squeeze on an outer peripheral surface side is reduced over time due to creep deformation

Methodology Applied
Scientific EffectCreep deformation: Creep

Implementation Method 2

shrinking of the diameter of the seal ring in a low-temperature condition

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP2957795B1Sealing structure
Publication Date: 2019.11.06 NOK CORP
  • EP2957795B1 patent drawingFigure 1~2
  • EP2957795B1 patent drawingFigure 3~4

AI summary

Provided is a sealing device which is capable of exhibiting a sealing function even when it is in a state in which squeeze of a seal ring is reduced and in a low-temperature condition. A sealing structure is provided with a cylinder head (300) for an engine which has an injector mounting hole (310) and is exposed to high pressure gas; an injector which is mounted in the injector mounting hole (310); and a seal ring (100) made of resin which seals an annular gap between the injector mounting hole (310) and the injector (200), wherein a step having a larger diameter on a combustion chamber side (E) where the high pressure gas is present is formed on an inner peripheral surface of the injector mounting hole (310), and the seal ring (100) is attached to a position where the seal ring is in close contact with a step surface (310c) of the step.