Pipe Connection Screw Coating for Tightening and Anti-Loosening

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Solution Overview

Problem

Existing screw elements for connecting motor vehicle pipelines, such as brake pipes, face difficulties in maintaining a secure connection due to reduced sliding friction during tightening, making it harder to loosen the screw connection, and the coating application processes are time-consuming and costly.

Innovation Solution

A union screw with a metal substrate, featuring an inner coating of lubricating nanoparticles between the outer coating and the substrate, where the inner coating is applied only on contact surfaces and contains a polymer and nanoparticles of a lubricating solid, while the outer coating covers the majority of the screw element, providing a higher coefficient of friction to prevent loosening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an outer coating with lower coefficient of friction is applied to contact surfaces, then tightening is easier, but the screw connection becomes harder to loosen and may unintentionally loosen

Engineering Contradiction:
Improvetightening easeVSAvoidconnection security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies different friction characteristics to different locations: the outer coating with lower friction is applied only to contact surfaces to facilitate tightening, while the thread region retains higher friction to prevent unintentional loosening. This spatial differentiation of friction properties resolves the contradiction between ease of tightening and connection security.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The coating system is segmented into an outer coating layer and an inner coating layer with distinct functions. The outer coating provides low friction at contact surfaces for easy tightening, while the inner coating provides high friction at the thread region for secure connection, preventing the contradiction from manifesting.

Inventive Principle:
Principle #1Segmentation

2Reliability

If traditional electroplating or vapor deposition is used to apply coatings, then corrosion resistance is improved, but the process becomes time-consuming and costly

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcoating application time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces traditional electroplating or vapor deposition processes with a coating application method that is faster and less costly. The coating is applied in a manner that avoids the time-consuming and expensive traditional methods while maintaining corrosion resistance through the dual-layer coating structure.

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

Solution Approach 2:

The patent changes the application parameters of the coating process to achieve faster application. By modifying how the coating is applied (using a different method than electroplating or vapor deposition), the process becomes less time-consuming and costly while still providing adequate corrosion protection.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a continuous inner coating is applied over the entire screw element, then corrosion protection is maximized, but dimensional accuracy and coating application precision become more difficult to achieve

Engineering Contradiction:
Improvecorrosion protectionVSAvoiddimensional accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The inner coating is applied selectively only where corrosion protection is most critical (thread region and contact surfaces) rather than continuously over the entire screw element. This localized application maintains adequate corrosion protection while improving dimensional accuracy and reducing coating application complexity.

Inventive Principle:
Principle #3Local quality

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 effectively prevents unintentional loosening by allowing the coatings to slide over each other during tightening, maintaining a secure connection and enhancing corrosion resistance through crack prevention, while being easier and less expensive to apply, with improved dimensional accuracy.

Implementation Method 1

the inner coating being arranged in the region of the at least one contact surface, the outer coating containing a first polymer and nanoparticles of a first solid, the inner coating containing nanoparticles of a lubricating solid

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

the outer coating containing a first polymer and nanoparticles of a first solid... the first solid has a Mohs hardness of >7 and preferably >8

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2952796B1Screw element for the connection of pipes and pipe connection device with this screw element
Publication Date: 2022.09.28 TI AUTOMOTIVE HEIDELBERG
  • EP2952796B1 patent drawingFigure 1
  • EP2952796B1 patent drawingFigure 2

AI summary

A screw element (1) for connecting pipelines (2), preferably automotive pipelines. The screw element has a thread (3) and at least one unthreaded contact surface (4, 5). The screw element has an outer coating (7) and an inner coating (8). The outer coating (7) contains a first polymer and nanoparticles of a first solid.