Sealing Structure Radial Side Lip Labyrinth Design

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Solution Overview

Problem

Existing sealing structures with labyrinth designs face challenges when the reinforcing ring has a short inward flange part, as it prevents the formation of a side lip and can lead to damage during mounting and stacking, and requires additional weight and costly processing for the annular groove.

Innovation Solution

A sealing structure with a tubular part having a small-diameter and large-diameter section, where the side lip extends radially inward from the inward flange part, and the outer circumferential surface of the large-diameter part is tapered, forming an annular gap with the side lip to create a labyrinth structure without blocking the inward flange and allowing for direct mounting and stacking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the inward flange part is made shorter to save space, then the mounting space is reduced, but the side lip cannot be formed and the opening may be blocked

Engineering Contradiction:
Improvemounting spaceVSAvoidmounting operation
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The side lip is positioned at a location radially inward from the inward flange part, utilizing the radial dimension rather than extending axially. This allows the side lip to be formed without increasing the axial length of the inward flange part, thus saving mounting space while maintaining the sealing function.

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

Solution Approach 2:

The sealing body is divided into multiple functional parts: the oil lip for sealing, the dust lip for protecting against contaminants, and the side lip for preventing foreign substance entry. This segmentation allows each part to perform its specific function independently, with the side lip positioned radially inward to prevent blocking the opening during mounting.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the side lip is configured to increase in diameter toward the opposite side from the sealed-fluid side, then foreign substances are prevented from entering, but the opening may be blocked during mounting

Engineering Contradiction:
Improveforeign substance entryVSAvoidmounting operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The side lip is configured with a specific geometry where it increases in diameter toward the opposite side from the sealed-fluid side, but only up to a certain point. The key is that it does not extend to block the opening, creating a local quality difference that prevents foreign substance entry while allowing mounting access.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of extending the side lip axially to prevent foreign substance entry (which would block the opening), the invention uses the radial dimension by positioning the side lip radially inward from the inward flange part. This dimensional change allows the side lip to perform its protective function without interfering with the mounting operation.

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

3Object-affected harmful factors

If an annular groove is added to create a labyrinth structure, then foreign substance entry is minimized, but the body part becomes heavier and requires costly cutting processes

Engineering Contradiction:
Improveforeign substance entryVSAvoidmanufacturing cost and weight
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The labyrinth structure is merged with the side lip itself, rather than being a separate annular groove in the body part. The side lip's geometry creates the labyrinth effect, combining the sealing function and the foreign substance prevention function into a single integrated component, thereby eliminating the need for additional cutting processes and reducing weight.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts the labyrinth structure from the body part and relocates it to the side lip. This extraction eliminates the need for cutting an annular groove in the body part, reducing manufacturing complexity and cost, while maintaining the labyrinth effect for preventing foreign substance entry.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3222891B1Sealing structure
Publication Date: 2020.07.29 NOK CORP
  • EP3222891B1 patent drawingFigure 1
  • EP3222891B1 patent drawingFigure 2
  • EP3222891B1 patent drawingFigure 3

AI summary

Provided is a sealing structure that allows for formation of a side lip, as well as a labyrinth structure between an oil seal and a torsional vibration damper, even when a reinforcing ring has a short inward flange part. The sealing body 120 includes a side lip 124 extending from near a distal end of an inward flange part 112 of the reinforcing ring 110 radially inward and further toward an air side (A) than a dust lip 122 to a position not as far as the outer circumferential surface of a tubular part 210. The tubular part 210 includes a small-diameter part 211 on which the dust lip 122 slides, and a large-diameter part 212 on the air side (A). The large-diameter part 212 has a tapered surface 212a formed on an outer circumferential surface thereof that reduces in diameter toward the air side (A). An annular gap S is formed between this tapered surface 212a and an inner circumferential surface of the side lip 124.