Hydraulic Pipe Fitting Alignment and O-Ring Preload Control

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Solution Overview

Problem

Existing ORFS pipe connection systems for off-road vehicles face difficulties in aligning male and female fittings coaxially for threaded connections and determining the correct preload for O-rings, leading to potential leakage and installation challenges.

Innovation Solution

The pipe connection system incorporates centering means, such as a Seeger ring, and preloading means, including a threaded connection between engaging elements, to ensure precise coaxial alignment and controlled axial force application on sealant O-rings, facilitating easy and correct installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional ORFS connection system is used, then the system is simple and cost-effective, but it is difficult to align male and female fittings coaxially for threaded connection

Engineering Contradiction:
Improvesimplicity and cost-effectiveness of connection systemVSAvoidalignment difficulty of male and female fittings
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

A centering ring is introduced as an intermediary component between the male and female fittings. The centering ring has an inner diameter that fits over the male fitting and an outer diameter that fits inside the female fitting, acting as a mediator to establish coaxial alignment. This allows the threaded connection to be performed accurately without direct manual alignment of the fittings themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The centering ring is placed on the male fitting before the threaded connection is made, performing the alignment action in advance. This preliminary centering action ensures that when the female fitting is subsequently attached, the threaded connection can be made easily and correctly without requiring precise manual alignment during the connection process.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If traditional ORFS connection system is used, then the system structure is simple, but it is difficult to determine correct preload for O-rings

Engineering Contradiction:
Improvesimplicity of connection system structureVSAvoidpreload accuracy of O-rings
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A preloading element is introduced as an intermediary component between the male and female fittings, positioned after the O-ring. This element provides a controlled mechanism for applying axial preload to the O-ring seal, ensuring correct sealing force without requiring complex adjustment procedures or specialized tools.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The preloading element is designed to automatically apply the correct preload to the O-ring when the connection is made, performing the preloading action as part of the standard installation process. This eliminates the need for separate preload adjustment steps and ensures consistent sealing performance.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If manual alignment and preloading is used, then the system requires less components, but installation time and skill requirement increases

Engineering Contradiction:
Improvenumber of components in connection systemVSAvoidinstallation time and skill requirement
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The centering ring and preloading element serve as intermediary components that perform alignment and preloading functions automatically during installation. These components guide the assembly process and ensure correct positioning and sealing without requiring high installation skill or extensive time, despite adding minimal structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3789647B1Pipe connection system for hydraulic pipes of an off-road vehicle
Publication Date: 2023.04.26 CNH IND ITALIA SPA
  • EP3789647B1 patent drawingFigure 1A~1B
  • EP3789647B1 patent drawingFigure 2~3A
  • EP3789647B1 patent drawingFigure 3B~3C

AI summary

Pipe connection system (1) for connecting a first portion (4) and a second portion (5) of a hydraulic arrangement, a male fitting (2) provided with a male element (6) connected to the first portion (4) and a female fitting (3) provided with a female element (8) connected to the second portion (5), the female fitting (3) being provided with centering means (16) configured to position the female fitting (3) on the male fitting (2) coaxially to a common axis (A) and preloading means (17) configured to impart a force to male and female elements (6, 8) so that they are pushed one against the other, thereby compressing sealant means (12) interposed between male and female elements (6, 8).