Seal Lip Interference Positioning for Accurate Sealing Alignment

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Solution Overview

Problem

Conventional sealing structures face challenges in accurate positioning due to dimensional issues, leading to eccentric arrangement and uneven contact, which affects sealing effectiveness.

Innovation Solution

A sealing structure with a first seal lip and a support ring, where the seal lip end has interference with the inner and first end walls, producing radial and axial reaction forces to radially and axially position the support ring, ensuring accurate alignment and stable orientation within the attachment space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the outer peripheral surface of the lip seal does not contact the outer peripheral wall due to dimensional constraints, then the lip seal can be installed with easier tolerance, but the positioning accuracy and sealing effectiveness deteriorate due to eccentric arrangement

Engineering Contradiction:
Improveinstallation toleranceVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary positioning mechanism consisting of the seal-lip end contacting both the inner peripheral wall and the first end wall. This intermediary contact point serves as a mediator that transfers positioning information from the inner peripheral wall to the outer peripheral surface, ensuring accurate positioning even when the outer peripheral surface does not directly contact the outer peripheral wall.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The seal-lip end is designed to preliminarily establish contact with the inner peripheral wall and first end wall during installation. This preliminary action of contacting the inner peripheral wall and end wall beforehand ensures that the lip seal is correctly positioned before the final sealing contact is made, preventing eccentric arrangement.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the seal-lip end contacts both the inner peripheral wall and first end wall with interference, then positioning accuracy improves, but the device complexity increases due to interference fit design

Engineering Contradiction:
Improvepositioning accuracyVSAvoidinterference fit design
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent utilizes parameter changes in the form of interference fit, where the seal-lip end has slightly different dimensions than the contact surfaces of the inner peripheral wall and first end wall. This dimensional parameter change creates the necessary interference for accurate positioning while maintaining a relatively simple overall design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of making the outer peripheral surface contact the outer peripheral wall for positioning, the patent inverts the approach by having the seal-lip end contact the inner peripheral wall and end wall. This inverted positioning strategy achieves accurate positioning through a different contact configuration that is actually simpler to implement.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If the outer peripheral wall does not serve to position the lip seal, then the attachment space definition becomes simpler, but the sealing effectiveness deteriorates due to uneven contact

Engineering Contradiction:
Improveattachment space definitionVSAvoidsealing effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The seal-lip end is designed to self-position by contacting the inner peripheral wall and first end wall with interference. This self-service positioning mechanism eliminates the need for the outer peripheral wall to serve as a positioning surface, simplifying the attachment space definition while ensuring even contact and effective sealing through proper alignment.

Inventive Principle:
Principle #25Self-service

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 enables accurate positioning of the sealing device in both radial and axial directions, enhancing attachment workability and maintaining high resistance to pressure while improving sealing effectiveness.

Implementation Method 1

the first seal-lip end has a certain amount of interference with the inner peripheral wall and the first end wall so that its radial reaction force radially presses the support ring outward and its axial reaction force presses the support ring toward the second end wall

Methodology Applied
Scientific EffectInterference fit:

Implementation Method 2

its radial reaction force radially presses the support ring outward and its axial reaction force presses the support ring toward the second end wall

Methodology Applied
Scientific EffectReaction force: Reaction (physics)

Data Source

PatentEP3760901B1Sealing structure
Publication Date: 2023.09.13 NOK CORP
  • EP3760901B1 patent drawingFigure 1
  • EP3760901B1 patent drawingFigure 2
  • EP3760901B1 patent drawingFigure 3

AI summary

A sealing structure which can be accurately positioned in the attachment space (14) is provided. A sealing structure includes a sealing device (21) including a first seal lip (27) having a first seal-lip end (27a), and a support ring (22) that supports the first seal lip (27); and a plurality of members that define an attachment space (14) into which the sealing device (21) is attached, the members including an inner peripheral wall (15) arranged on the inner periphery side of the sealing device (21), a first end wall (16) arranged on one axial end of the sealing device (21), and a second end wall (17) arranged on another axial end of the sealing device (21). The first seal-lip end (27a) has a certain amount of interference with the inner peripheral wall (15) and the first end wall (16) so that its radial reaction force radially presses the support ring (22) outward and its axial reaction force presses the support ring (22) toward the second end wall (17).