Piston-Cylinder Assembly Using Low-Temperature Welding

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Solution Overview

Problem

The existing assembly method for piston-cylinder groups involves lengthy processes due to the need for high heat dissipation after welding, which damages thermoplastic seal gaskets and increases production costs.

Innovation Solution

A method that incorporates low-temperature welding using cold metal transfer (CMT) to assemble the piston-cylinder group, allowing seal gaskets to be inserted before welding and performing simultaneous low-temperature welds between the cylinder and head or base, reducing energy consumption and preserving gasket integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional welding process is used to join head to cylinder, then strong welding joint is achieved, but high heat damages thermoplastic seal gaskets and increases assembly time

Engineering Contradiction:
Improvewelding joint strengthVSAvoidassembly time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent applies parameter changes by transitioning from conventional high-temperature welding to low-temperature welding processes. This involves modifying the thermal parameters of the welding operation to maintain joint strength while reducing heat input to levels that do not damage thermoplastic seal gaskets, thereby eliminating the need for lengthy cooling periods and reducing overall assembly time

Inventive Principle:
Principle #35Parameter changes

2Temperature

If conventional welding process is used, then adequate welding temperature is achieved, but thermoplastic seal gaskets are damaged

Engineering Contradiction:
Improvewelding temperatureVSAvoidheat damage to seal gaskets
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the temperature parameter of the welding process by implementing low-temperature welding techniques. This allows the welding operation to proceed at reduced thermal levels that are sufficient to create adequate welding joints while remaining below the damage threshold for thermoplastic seal gaskets, thus eliminating heat damage to these components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by installing the thermoplastic seal gaskets into the cylinder before the welding operation takes place. This sequencing allows the gaskets to be positioned and secured prior to welding, and the subsequent low-temperature welding process does not expose them to damaging heat levels, preserving their integrity

Inventive Principle:
Principle #10Preliminary action

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 method significantly reduces assembly time and costs by maintaining low temperatures during welding, enabling a rapid and economical assembly process while protecting the seal gaskets.

Implementation Method 1

low-temperature welding step of a base to an end of the cylinder not coupled to the head

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3252319B1Method of assembling a piston-cylinder group through low temperature welding
Publication Date: 2021.03.03 OGNIBENE POWER
  • EP3252319B1 patent drawingFigure 1
  • EP3252319B1 patent drawingFigure 2~3
  • EP3252319B1 patent drawingFigure 4~5

AI summary

An assembly method of a piston-cylinder group (10), where the piston-cylinder group (10) comprises a cylinder (20) at an end of which a head (40) is fixable, provided with seal gaskets (43), where the method comprises steps of: - mounting the seal gaskets (43) in appropriate seatings in the head (40); - coupling the head (40) with the cylinder (20); and - a low-temperature welding of the coupling between the head (40) and the cylinder (20).