Seal Ring Divided Body Reduces Rotary Torque

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Solution Overview

Problem

Conventional seal rings for annular gaps between shafts and housings face challenges in reducing rotary torque while maintaining stable sealing performance, often resulting in excessive contact area variability and potential deformation, especially with chamfers at the interface.

Innovation Solution

A seal ring configuration using two divided bodies made of resin material, with alternating fitted raised and recessed portions, allowing for a narrower effective pressure receiving area from the inner peripheral surface and a stable sliding section, reducing rotary torque and enhancing sealing stability by eliminating undercut sections and facilitating reliable sliding with the shaft hole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the contact area of the sliding portion between the seal ring and the side wall surface of the annular groove is reduced, then rotary torque is reduced, but sealing performance becomes unstable and contact region may deform

Engineering Contradiction:
Improverotary torqueVSAvoidsealing performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The seal ring is divided into a sliding portion and a sealing portion with distinct functions. The sliding portion contacts the shaft hole inner peripheral surface to enable rotation with reduced torque, while the sealing portion contacts the side wall surface of the annular groove to maintain stable sealing performance. This segmentation allows each portion to be optimized independently for its specific function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the seal ring are given different properties and dimensions. The sliding portion has a smaller contact area with the shaft hole to reduce friction and rotary torque, while the sealing portion has an appropriately sized contact area with the side wall surface to ensure reliable sealing. The width of each portion is specifically designed to match the requirements of its function.

Inventive Principle:
Principle #3Local quality

2Productivity

If the seal ring structure is simplified to reduce manufacturing complexity, then production efficiency is improved, but sealing performance stability may be compromised

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidsealing performance stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The seal ring is designed as a unitary molded product with integrated sliding and sealing portions, eliminating the need for separate components and post-assembly operations. The different functional portions are formed in a single injection molding process, achieving both manufacturing simplicity and functional reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The widths of the sliding portion and sealing portion are carefully controlled within specific ranges to achieve the desired balance between rotary torque reduction and sealing performance. By optimizing these dimensional parameters during mold design, the seal ring delivers reliable performance without requiring complex manufacturing processes.

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 effectively reduces rotary torque and stabilizes sealing performance by ensuring consistent sliding contact and reduced friction, even with varying gap sizes between the shaft and housing, while eliminating the need for post-processing and reducing costs through injection molding.

Implementation Method 1

the seal ring, having a through hole provided to lead to a bottom surface of the recessed section from an inner peripheral surface side and to enable sealed fluid to be introduced into the recessed section from the inner peripheral surface side, is configured so that an effective pressure receiving area from the inner peripheral surface side that contributes to a force pressing against an inner peripheral surface of the shaft hole by the fluid pressure is narrower than an effective pressure receiving area from the inner peripheral surface side that contributes to a force pressing against a side wall surface of the annular groove on a low pressure side

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP2910824B1Seal ring
Publication Date: 2018.11.21 CARL FREUDENBERG KG
  • EP2910824B1 patent drawingFigure 1~3
  • EP2910824B1 patent drawingFigure 4~5
  • EP2910824B1 patent drawingFigure 6~8

AI summary

Provided is a seal ring that stabilizes sealing performance while reducing rotary torque. A recessed section (140) provided centrally in a width direction and extending in a circumferential direction and a pair of raised sections (150) provided on both sides of the recessed section that slide with respect to an inner peripheral surface of a shaft hole is provided on an outer peripheral surface side. A through hole (141) a is provided so as to lead to a bottom surface of the recessed section 140 from an inner peripheral surface side and allows a sealed fluid to be introduced into the recessed section from the inner peripheral surface side. An effective pressure receiving area from the inner peripheral surface side that contributes to a force being pressed against the inner peripheral surface of the shaft hole by the fluid pressure is thereby narrower than an effective pressure receiving area from a side surface side that contributes to a force being pressed against the side wall surface of an annular groove on the low pressure side by the fluid pressure. A seal ring (100) is configured by the combination of a first divided body (100A) on a high pressure side and a second divided body (100B) on a low pressure side with respect to an axis direction.