Mechanical Seal Detent Locking Without Clinching

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Solution Overview

Problem

Conventional mechanical seals for submersible and surface pumps face issues with clinching methods causing distortion or cracking of the rotating-side seal ring, and adhesive application leading to leakage, as they require clinching means or non-drying adhesives, which complicate the joining process and affect sealing efficiency.

Innovation Solution

A mechanical seal design featuring cutout grooves and detent convex areas on the rotating-side seal ring and case, respectively, allows for secure locking without clinching or adhesive use, ensuring the seal ring is constantly pressed and securely engaged with other components, eliminating the need for precise dimensional relationships and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If clinching means is used to join the rotating-side seal ring with the bellows or other rotating side components, then the joining strength is improved, but the rotating-side seal ring may distort or crack due to excessive clinching

Engineering Contradiction:
Improvejoining strengthVSAvoidseal ring integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the mechanical clinching system with a detent engagement system. The detent convex area on the case engages with the detent cutout area on the rotating-side seal ring through a detent groove, providing joining strength through geometric interlocking rather than forceful deformation. This eliminates the risk of distortion or cracking while maintaining secure attachment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The joining mechanism is segmented into distinct functional elements: the detent convex area (protrusion), the detent cutout area (reception zone), and the detent groove (guiding pathway). This segmentation allows each component to perform its specific function - the convex area provides engagement, the cutout area receives it, and the groove guides the engagement process - resulting in a reliable join without excessive stress on any single part.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If non-drying adhesive is applied to join the rotating-side seal ring with the bellows, then the joining is simplified, but adhesive leakage occurs and may attach to the sealing face causing higher torque or starting problems

Engineering Contradiction:
Improvejoining process simplicityVSAvoidsealing performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the chemical adhesive joining method with a mechanical detent engagement system. The detent convex area engages with the detent cutout area through the detent groove, providing a secure mechanical connection that eliminates the need for adhesives. This prevents adhesive leakage and contamination of the sealing face while maintaining joining simplicity through the self-aligning detent mechanism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If precise dimensional relationships are maintained in the joining components, then the assembly accuracy is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improveassembly accuracyVSAvoiddimensional control requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The detent engagement mechanism is designed to be self-aligning and self-regulating. The detent groove guides the detent convex area into the detent cutout area during assembly, automatically establishing the correct positional relationship without requiring pre-coordinated dimensions. The geometry of the detent structures themselves ensures proper alignment, eliminating the need for complex dimensional control in manufacturing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of requiring precise dimensional relationships to be maintained throughout the component design, the patent inverts the approach by designing the joining mechanism to create its own positional reference. The detent convex area and detent cutout area engage to automatically establish the correct position, reversing the traditional approach where dimensions dictate position. This simplifies manufacturing while ensuring assembly accuracy.

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

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 design enhances the service life and reliability of the seal ring by preventing distortion, leakage, and chipping, while maintaining effective sealing and easy assembly, regardless of rotational direction.

Implementation Method 1

a rotating-side seal ring which is pressed against the stationary-side seal ring by the axial-direction bias force of a coil spring

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a bellows that functions as an actuating shaft gasket is present between the outer periphery face of the rotational axis 50 and a back face 33a of the rotating-side seal ring 33

Methodology Applied
Scientific EffectFlexible sealing: Elasticity

Data Source

PatentEP3187756B1Mechanical seal
Publication Date: 2020.02.05 EAGLE INDS
  • EP3187756B1 patent drawingFigure 1
  • EP3187756B1 patent drawingFigure 2
  • EP3187756B1 patent drawingFigure 3(a)~3(c)

AI summary

A rotating-side seal ring is joined as one piece with bellows and other component members on a rotating side except a rotating-side seal ring, without using any clinching means or adhering means involving adhesive. A mechanical seal, comprising: a bellows 10 that seals between a rotating-side seal ring 5 biased in the axial direction by a biasing member 9, and the outer periphery face of the rotational axis 2; a case 11 fitted to the rotating-side seal ring 5 and the outer periphery of the bellows 10; and a drive ring 12 that tightens the bellows 10 to the rotational axis 2, is characterized in that: a plurality of cutout grooves 5b running through in the axial direction are provided on the outer periphery area of the rotating-side seal ring 5; detent cutout areas 5d are provided on the side face of the rotating-side seal ring 5 on a sealing face S side in a manner extending in the circumferential direction from the cutout grooves 5b; and detent convex areas 11e are provided at the edge area of the case 11 on the rotating-side seal ring 5 side in a manner facing the cutout grooves 5b and bulging in the inner-diameter direction so as to be able to pass through the cutout grooves 5b.