Opposed Flank Threaded Element for Axial Clearance Management

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Solution Overview

Problem

Existing threaded connections struggle to effectively manage both tensile and compressive loads due to axial clearance issues, which reduce performance under compressive loads, especially in applications subject to varying loads and temperature changes.

Innovation Solution

The design features male and female threaded elements with opposed inclinations of stabbing and loading flanks, creating buffer zones that absorb axial clearance, allowing the connections to handle high tensile, compressive, and bending loads by adjusting the angle and configuration of the threading portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If axial clearance is provided between threads to allow easy engagement and absorb dimensional variations, then ease of operation and manufacturing precision are improved, but compressive load transfer capability deteriorates

Engineering Contradiction:
Improveease of engagementVSAvoidcompressive load transfer
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The threading is divided into two distinct portions: a first threading portion with threads having a first flank angle, and a second threading portion with threads having a second flank angle. This segmentation allows each portion to be optimized for different functions - one for engagement ease and the other for load transfer under compression.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the threading have different geometric properties. The first threading portion has specific flank angles optimized for easy engagement and clearance absorption, while the second threading portion has different flank angles optimized for compressive load transfer. This local differentiation resolves the contradiction by assigning different qualities to different parts of the same component.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If axial clearance is provided to accommodate temperature variations and bending loads, then adaptability is improved, but compressive performance deteriorates

Engineering Contradiction:
Improvetolerance to temperature and bending variationsVSAvoidcompressive load capacity
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The threading is segmented into two portions with different geometric characteristics. The first portion handles engagement and clearance requirements for adaptability, while the second portion is optimized for maintaining compressive strength under varying operational conditions including temperature and bending loads.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first threading portion is designed with specific flank angles to accommodate thermal expansion and bending-induced clearances, while the second threading portion maintains optimized geometry for compressive load transfer, allowing the connection to adapt to environmental variations without sacrificing structural integrity.

Inventive Principle:
Principle #3Local quality

3Device complexity

If traditional single-threading design is used to simplify manufacturing, then device complexity is reduced, but ability to handle alternating tensile and compressive loads deteriorates

Engineering Contradiction:
Improvethreading configurationVSAvoidperformance under alternating loads
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Instead of a single uniform threading, the connection uses two distinct threading portions with different flank angles. This segmentation enables the first portion to optimize for one type of loading while the second portion optimizes for the opposite loading condition, significantly improving reliability under alternating tensile and compressive loads.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual-threading design allows the connection to dynamically adapt to different loading conditions. Under tension, one threading portion engages optimally, while under compression, the other portion engages optimally, providing consistent performance across varying load scenarios without requiring complex active control mechanisms.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2167783B2Threaded element of a component with opposed threading portions and corresponding tubular threaded connection
Publication Date: 2017.08.23 VALLOUREC MANNESMANN OIL & GAS FRANCE
  • EP2167783B2 patent drawingFigure 1~2
  • EP2167783B2 patent drawingFigure 3~5
  • EP2167783B2 patent drawingFigure 6a~8B

AI summary

A threaded element (EM) of a component (T2) comprises at least first (FE1) and second (FE2) threading portions each comprising threads (TH1, TH2) each comprising a stabbing flank and a loading flank. The stabbing flanks and loading flanks of the threads (TH1) of the first threading portion (FE1) and the threads (TH2) of the second threading portion (FE2) are inclined in an opposed manner with respect to the radial direction.