Seal Ring Static Pressure Grooves for Cavitation-Stable Lubrication

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Solution Overview

Problem

The existing seal ring designs experience unstable lubrication performance at high-speed rotation due to cavitation caused by uneven pressure distribution across the circumferential direction, leading to non-uniform fluid films and reduced lubricity.

Innovation Solution

A seal ring with static pressure grooves arranged in a circumferential direction on the sealed fluid side and closed on the outer diameter side, allowing high-pressure fluid to flow radially and maintain a balanced fluid film across a wide range of rotation speeds, enhanced by extension and communication grooves for improved lubricity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic pressure grooves with shallow grooves on both sides of a deep groove are provided in the circumferential direction, then lubricity is improved by generating positive pressure and forming a fluid film, but cavitation occurs at high-speed rotation due to uneven pressure distribution causing unstable lubrication

Engineering Contradiction:

Improvelubrication stabilityVSAvoidcavitation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The seal ring sliding surface is segmented into multiple functional zones: a sealed fluid introduction groove for introducing high-pressure fluid, multiple static pressure grooves arranged circumferentially for generating stable pressure, dynamic pressure grooves for generating hydrodynamic pressure, and communication grooves for fluid communication between zones. This segmentation allows each zone to perform its specific function, preventing cavitation while maintaining stable lubrication.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sliding surface are given different groove configurations tailored to their specific functions. The sealed fluid introduction groove has a specific depth and opening configuration for optimal fluid introduction. Static pressure grooves have varying depths and circumferential arrangements for stable pressure generation. Dynamic pressure grooves have inclined bottom surfaces for hydrodynamic pressure generation. This local optimization ensures each region contributes to stable lubrication without causing cavitation.

Inventive Principle:

Principle #3Local quality

2Reliability

If the seal ring is pressed to the housing side by high-pressure sealed fluid, then sealing performance is improved, but friction loss increases due to sliding surface contact

Engineering Contradiction:

Improvesealing performanceVSAvoidfriction loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The seal ring utilizes hydraulic pressure from the sealed fluid to achieve both sealing and lubrication functions. High-pressure sealed fluid is introduced through the sealed fluid introduction groove and distributed to static and dynamic pressure grooves, generating fluid pressure that maintains the fluid film between sliding surfaces. This hydraulic approach reduces direct sliding contact friction while the fluid pressure differential maintains effective sealing at the clearance between the rotary shaft and housing.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The groove depths, circumferential lengths, and arrangements are specifically designed to optimize the balance between sealing pressure and lubrication film formation. The static pressure grooves have depths and circumferential spacings that generate stable pressure without excessive friction. The dynamic pressure grooves have inclined bottom surfaces that generate hydrodynamic pressure sufficient for fluid film formation. These parameter optimizations ensure effective sealing while minimizing friction loss through proper fluid film thickness control.

Inventive Principle:

Principle #35Parameter changes

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 stable lubrication performance across varying rotation speeds by ensuring a balanced fluid film distribution, reducing abrasion and maintaining effective sealing, even at high speeds.

Implementation Method 1

high-pressure sealed fluid introduced into the static pressure grooves mainly flows out to follow a rotation direction of the rotary shaft

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

a fluid film is formed between the sliding surfaces, and lubricity between the sliding surfaces is maintained

Methodology Applied

Scientific EffectLubrication: Lubrication

Implementation Method 3

the technique of generating a dynamic pressure between the sliding surfaces by rotation of the rotary shaft to slide the sliding surfaces with a fluid film of the sealed fluid being interposed

Methodology Applied

Scientific EffectDynamic pressure: Hydrodynamic Cavitation

Data Source

PatentUS11530749B2Seal ring

Publication Date: 2022.12.20 EAGLE INDS

AI summary

Provided is a seal ring configured so that stable lubrication performance can be provided across a wide range of rotation speed. A seal ring for sealing a clearance between a rotary shaft and a housing includes multiple static pressure grooves provided at a sliding surface of the seal ring and arranged in a circumferential direction, the static pressure grooves being opened on a sealed fluid side and closed on an outer diameter side, a circumferential length of each of the static pressure grooves being shorter than a radial length of each of the static pressure grooves.