Pipe Joint Cap and O-Ring Clearance for Shaft Misalignment

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Solution Overview

Problem

Existing pipe joints with elastic bodies for center misalignment face challenges in maintaining adequate sealability and efficiently absorbing shaft center misalignment.

Innovation Solution

A pipe joint design featuring a male joint with a cap and O-ring, where the O-ring's cross-section diameter is 3 to 10 mm, and a clearance of 3 to 13% between the male joint main body and cap, allowing for compressive deformation to absorb misalignment and maintain sealability, combined with a female joint having a similar O-ring configuration for radial movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an elastic body with V-shaped cross-section is used to support the connection body and base body, then the connection body can shift relative to the base body to absorb shaft center misalignment, but adequate sealability cannot be ensured

Engineering Contradiction:
Improvemisalignment absorptionVSAvoidsealability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a spherical surface as an intermediary between the connection body and base body. The sphere allows relative shifting to absorb misalignment while the O-ring provides sealing. This mediator resolves the contradiction by separating the functions of movement absorption and sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the geometric parameters by introducing a spherical surface with specific radius relationships (R1, R2, R3) and controlling the gap dimensions. These parameter changes enable both misalignment absorption through spherical rotation and sealing through controlled O-ring compression.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If O-rings are provided between the elastic body and base/connection bodies to prevent fluid leakage, then sealability is improved, but the configuration becomes more complex

Engineering Contradiction:
ImprovesealabilityVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The O-ring serves multiple functions simultaneously: it seals the gap between components, accommodates dimensional variations, and works with the spherical mechanism to enable misalignment absorption. This multi-functionality reduces the need for additional sealing components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses homogeneous O-ring material throughout the sealing interface, providing consistent sealing properties across different locations and conditions. This simplifies the sealing system compared to using multiple different sealing elements.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If the male joint and female joint are designed with tight clearance to ensure sealability, then fluid leakage is prevented, but misalignment of shaft centers cannot be absorbed

Engineering Contradiction:
ImprovesealabilityVSAvoidmisalignment absorption
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a static rigid connection to a dynamic spherical connection that can rotate and adjust. The spherical surface allows the connection body to dynamically shift position relative to the base body, absorbing misalignment while maintaining sealing through the O-ring.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent adds rotational freedom in another dimension by introducing the spherical surface. Instead of linear adjustment, the sphere enables angular adjustment, allowing misalignment absorption in multiple directions while maintaining the sealing gap.

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

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 design effectively connects male and female joints while absorbing shaft center misalignment, ensuring sealability and improving the efficiency of connecting multiple pipes by compressive deformation of the O-rings, preventing fluid leakage even with significant misalignment.

Implementation Method 1

maintaining the sealability by compressive deformation of the male joint O-ring in a radial direction

Methodology Applied
Scientific EffectCompressive deformation: Deformation

Data Source

PatentEP3521677B1Pipe joint and joint connection device
Publication Date: 2021.08.18 NITTA CORP
  • EP3521677B1 patent drawingFigure 1
  • EP3521677B1 patent drawingFigure 2~3
  • EP3521677B1 patent drawingFigure 4~5

AI summary

Provided are a pipe joint and a joint connection device that have simpler configurations and yet can prevent fluid leakage and absorb misalignment of shaft centers. A pipe joint 15 includes a male joint 12A and a female joint 18A into which the male joint 12A is inserted. The male joint 12A has a male joint main body 24A and a cap 26A that is fixed at a base end of the male joint main body 24A, with a male joint O-ring 36 interposed between the cap 26A and the male joint main body 24A. The cross-section diameter of the male joint O-ring 36 is 3 to 10 mm, and a clearance L1 between the male joint main body 24A and the cap 26A is 3 to 13% of the cross-section diameter of the male joint O-ring 36.