Seal Ring Groove Layout for Stable Lubrication at High Speed

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Solution Overview

Problem

The existing seal ring designs experience cavitation and unstable lubricity at high-speed rotation due to uneven fluid film distribution caused by dynamic pressure grooves configured with shallow grooves on the same circumference, leading to non-uniform fluid film and reduced lubrication performance.

Innovation Solution

The seal ring features dynamic pressure grooves with deep and shallow grooves arranged in a circumferential direction, where adjacent deep grooves communicate through a radial communication groove, allowing for balanced fluid supply and pressure generation across the circumference, ensuring stable lubrication performance across a wide range of rotation speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic pressure grooves are configured with shallow grooves on the same circumference as the deep groove, then the fluid film can be generated between sliding surfaces, but cavitation occurs at high-speed rotation and lubricity becomes unstable

Engineering Contradiction:
Improvelubricity stabilityVSAvoidcavitation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by positioning the shallow groove offset from the deep groove in the circumferential direction, rather than on the same circumference. This asymmetric arrangement creates a phased pressure distribution that prevents simultaneous extreme positive and negative pressures, thereby eliminating cavitation and stabilizing lubricity at high rotation speeds

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces a circumferential dimension offset between the deep groove and shallow groove positions. By arranging these grooves at different circumferential locations rather than radially aligned positions, the design creates a temporal and spatial separation of pressure generation zones, preventing cavitation while maintaining effective fluid film lubrication

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

2Speed

If the rotary shaft rotates at high speed, then the positive pressure increases and fluid film is formed, but non-uniform fluid film distribution causes unstable lubrication

Engineering Contradiction:
Improverotation speedVSAvoidfluid film uniformity
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The asymmetric circumferential positioning of shallow grooves relative to deep grooves creates a balanced pressure distribution pattern that maintains uniform fluid film thickness across the sliding surface, even at high rotation speeds where non-uniform distribution would otherwise occur

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

This configuration maintains a favorable balance of the fluid film thickness and pressure distribution, preventing cavitation and enhancing lubricity stability even at high speeds, ensuring effective sealing and reduced mechanical loss.

Implementation Method 1

generate 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: Pressure Gradient

Implementation Method 2

a positive pressure is generated in such a shallow groove. Then, the positive pressure increases due to wedge action caused by the inclined bottom surface of the rotation-direction-side shallow groove

Methodology Applied
Scientific EffectWedge action: Wedge

Implementation Method 3

adjacent two of the deep grooves of the dynamic pressure grooves in the circumferential direction are formed as a dynamic pressure groove unit configured such that the adjacent two of the deep grooves communicate with each other through a communication groove extending in the circumferential direction on an opposite side of the openings of the deep grooves in a radial direction

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 4

the seal ring seals a clearance between the rotary shaft and a housing to prevent leakage of sealed fluid (liquid)

Methodology Applied
Scientific EffectSealing: Physical Containment

Data Source

PatentEP3795868B1Seal ring
Publication Date: 2024.08.21 EAGLE INDS
  • EP3795868B1 patent drawingFigure 1
  • EP3795868B1 patent drawingFigure 2
  • EP3795868B1 patent drawingFigure 3

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 1 for sealing a clearance between a rotary shaft 2 and a housing 3 includes dynamic pressure grooves 12 formed at a sliding surface S1 of the seal ring 1 and arranged in a circumferential direction so as to be configured to generate dynamic pressure. The dynamic pressure grooves 12 include deep grooves 120 having openings on a sealed fluid side and shallow grooves 121 being shallower than the deep grooves. The shallower grooves 121 are formed continuously to the deep grooves 120 and extend to at least one side in the circumferential direction. At least adjacent two of the deep grooves 120, 120' of the dynamic pressure grooves 12, 12' in the circumferential direction are formed as a dynamic pressure groove unit 100 configured such that the adjacent two of the deep grooves 120, 120' communicate with each other through a communication groove 14 extending in the circumferential direction on an opposite side of the openings of the deep grooves 120, 120' in a radial direction.