Sealing Structure with Annular Member for Labyrinth Path

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Solution Overview

Problem

Existing sealing structures with torsional vibration dampers face challenges in forming a labyrinth structure when the oil seal lacks a side lip, as the difference between the inner and outer diameters becomes too small, preventing the adoption of the conventional labyrinth structure.

Innovation Solution

A sealing structure that includes an annular member fixed to the outer circumferential surface of the tubular part, covering the dust lip and creating a gap, forming a labyrinth structure between the oil seal and the torsional vibration damper without requiring a side lip, utilizing a cylindrical part with a tapered section to enhance the sealing path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a side lip is provided to the oil seal to form a labyrinth structure, then foreign substance entry is minimized, but the difference between inner and outer diameters increases

Engineering Contradiction:

Improveforeign substance entryVSAvoiddifference between inner and outer diameters

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The sealing structure is divided into multiple functional components: the oil seal with dust lip, the annular member with labyrinthine path, and the tubular part. This segmentation allows the labyrinth structure to be formed by the annular member rather than requiring a side lip on the oil seal, thus maintaining the original diameter constraints while achieving foreign substance protection

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The annular member acts as an intermediary component between the oil seal and the external environment. It provides the labyrinthine sealing path without requiring modifications to the oil seal structure itself, particularly without adding a side lip that would increase the diameter difference

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a labyrinth structure is formed using a side lip and annular groove, then sealing performance is improved, but device complexity increases

Engineering Contradiction:

Improvesealing performanceVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The side lip component is extracted from the oil seal structure and its sealing function is transferred to the annular member. This simplifies the oil seal design while maintaining the labyrinthine sealing effect through the annular member's groove structure

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of adding a side lip to the oil seal to create the labyrinth structure, the invention inverts the approach by providing the labyrinth structure through the annular member that interfaces with the dust lip. This reverses the traditional design paradigm and simplifies the overall structure

Inventive Principle:

Principle #13The other way round (Inversion)

3Object-affected harmful factors

If a side lip is added to the oil seal, then a confined path is formed, but manufacturing complexity and production costs increase

Engineering Contradiction:

Improveforeign substance entryVSAvoidproduction cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The annular member is designed as a simpler, more cost-effective component compared to modifying the oil seal with a side lip. The annular groove can be formed through standard machining processes, making production more economical while achieving the same sealing effect

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 solution allows for effective minimization of foreign substance entry without increasing torque, maintaining consistent sealing functionality and reducing production costs by eliminating the need for complex processing and side lip formation.

Implementation Method 1

an oil lip provided such as to be slidable on an outer circumferential surface of the tubular part

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

a dust lip provided further on an opposite side from the sealed-fluid side than the oil lip and slidable on the outer circumferential surface of the tubular part

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

a confined and complex path is formed from the air side to a sliding part between the dust lip and the outer circumferential surface of the tubular part. A labyrinth structure is thus provided

Methodology Applied

Scientific EffectLabyrinth structure:

Data Source

PatentEP3184865B1Sealing structure

Publication Date: 2019.10.02 NOK CORP

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AI summary

Provided is a sealing structure that allows for formation of a labyrinth structure between an oil seal and a torsional vibration damper even when the oil seal does not include a side lip. The oil seal 100 includes an oil lip 121 provided such as to be slidable on an outer circumferential surface of a tubular part 210, and a dust lip 122 provided further on an air side (A) than the oil lip 121 and slidable on the outer circumferential surface of the tubular part 210. An annular member 250 is further provided, which is fixed to the outer circumferential surface of the tubular part 210 further on the air side (A) than the dust lip 122 and covering an outer circumferential surface of the dust lip 122 such that there is a gap between the annular member 250 itself and the outer circumferential surface of the dust lip 122.