Split Seal Ring Groove Structure for Low Torque and Sealing

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Solution Overview

Problem

Existing seal rings with reduced radial dimensions face challenges in maintaining both sealing performance and reducing torque due to decreased rigidity and smaller dynamic pressure action, necessitating a configuration that balances these factors.

Innovation Solution

A seal ring design featuring a cut portion with decreasing radial dimensions and recessed parts on both surfaces, including enlarged communication portions that enhance dynamic pressure action while maintaining sealing integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the radial-direction dimension of the seal ring is decreased to improve sealing performance, then the seal ring can better approximate a perfect-circular column shape and reduce gaps with peripheral components, but the rigidity of the seal ring becomes lower and deformation occurs more easily

Engineering Contradiction:
Improvesealing performanceVSAvoidrigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The seal ring is divided into multiple radial sections with different thickness characteristics. The first radial section has a larger radial-direction dimension while the second radial section has a smaller radial-direction dimension, allowing different parts of the seal ring to serve different functions - the thicker section provides rigidity and the thinner section improves sealing contact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different radial sections of the seal ring are given different local properties. The first radial section is designed with greater thickness to maintain structural rigidity, while the second radial section is designed with smaller thickness to enhance sealing performance by reducing gaps with the inner and outer peripheral surfaces.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If a groove is formed in the end surface to cause dynamic pressure action and reduce torque, then an oil film can be formed between the end surface and the wall surface, but the radial-direction dimension of the groove becomes smaller toward the joining portion, reducing the area of the oil film and the dynamic pressure action

Engineering Contradiction:
ImprovetorqueVSAvoiddynamic pressure action
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The groove structure is segmented into different radial sections corresponding to the seal ring's radial sections. The first groove section is formed in the first radial section with sufficient radial dimension to provide adequate oil film area and dynamic pressure action for torque reduction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The groove is given different local characteristics in different radial sections. The first groove section is positioned in the thicker first radial section where it can accommodate sufficient radial dimension for effective dynamic pressure action, while the overall groove structure adapts to the varying thickness of the seal ring.

Inventive Principle:
Principle #3Local quality

3Reliability

If a wall part is provided to inhibit oil from passing through the groove in the radial direction, then sealing integrity is maintained, but the radial-direction dimension of the groove becomes smaller toward the joining portion, making it difficult to achieve both sealing performance improvement and torque reduction

Engineering Contradiction:
Improvesealing integrityVSAvoidtorque
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The seal ring structure is segmented into multiple radial sections with different thicknesses, allowing the groove to be positioned in the first radial section where it can have sufficient radial dimension for dynamic pressure action while the wall part in the second radial section provides sealing integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different radial sections are assigned different functional qualities - the first radial section accommodates the groove for torque reduction through dynamic pressure action, while the second radial section provides sealing integrity through the wall part structure.

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 design effectively reduces torque while improving sealing performance by ensuring adequate dynamic pressure action and stability, even with reduced radial dimensions.

Implementation Method 1

A dynamic pressure action is caused by forming such a groove, an oil film is formed between this end surface and a wall surface of a peripheral groove in which the seal ring is provided

Methodology Applied
Scientific EffectDynamic pressure action: Pressure Gradient

Data Source

PatentEP4636284A1Seal ring
Publication Date: 2025.10.22 NOK CORP
  • EP4636284A1 patent drawingFigure 1
  • EP4636284A1 patent drawingFigure 2
  • EP4636284A1 patent drawingFigure 3

AI summary

A seal ring having an annular shape and having one cut portion (2) includes: a pair of decreasing portions (5 and 6) in which a radial-direction dimension of the seal ring (1) decreases as the seal ring (1) approaches the cut portion (2); and a plurality of recessed parts (7) which are formed in at least one of end surfaces (1C and 1D) directed in an axis line (x) direction. The plurality of recessed parts (7) are configured with a first recessed part (7A) arranged in a range included in the decreasing portions (5 and 6) and a second recessed part (7B) arranged in a range spaced apart from the cut portion (2) with respect to the first recessed part (7A). Between an inner peripheral surface (1A) of the seal ring (1) and the second recessed part (7B), an inner periphery side wall part (9B) which demarcates both of those and a communication portion (91) which causes both of those to communicate with each other are formed. Between the inner peripheral surface (1A) of the seal ring (1) and the first recessed part (7A), an enlarged communication portion (74) is formed which causes both of those to communicate with each other. The enlarged communication portion (74) is formed with one portion, and a circumferential-direction dimension of the enlarged communication portion (74) is larger than a circumferential-direction dimension of the communication portion (91).