Welding Electrode Seal Support Structure for Bearing Pressure Isolation

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Solution Overview

Problem

The known welding electrodes, particularly those using a plain bearing and rod seal combination, are vulnerable to mechanical damage and reduced sealing effectiveness due to pressure applied during operation, leading to a short service life and high failure rates.

Innovation Solution

The design incorporates a housing with projections to separate and protect the rod seal, ensuring it is not pressed against the plain bearing uncontrollably, and features a larger inner diameter for the bearing seat to maintain the sealing effect, along with a snap ring for secure positioning, which enhances the operational reliability and service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the piston rod is slidably mounted in a housing and sealed by a rod seal, then the welding electrode can actively retract the centering pin, but the plain bearing moves in the direction of the rod seal and applies pressure to it, reducing sealing effectiveness and causing mechanical damage

Engineering Contradiction:
Improveactive retraction of centering pinVSAvoidsealing effectiveness and service life
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The housing is divided into two separate projection areas: a first projection for supporting the rod seal and a second projection for supporting the slide bearing. This segmentation prevents the slide bearing from pressing against the rod seal, eliminating the conflict between automation function and sealing reliability.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the slide bearing is positioned close to the rod seal for compact design, then the device complexity is reduced, but the rod seal suffers mechanical damage and sealing effectiveness is reduced under high pressure

Engineering Contradiction:
Improvecompact designVSAvoidsealing effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The housing acts as an intermediary structure with two distinct projections that mediate between the slide bearing and rod seal. This intermediary design maintains compactness while preventing direct contact and pressure application between the bearing and seal, ensuring sealing effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design significantly increases the service life and functional reliability of the welding electrode by preventing mechanical damage to the rod seal and maintaining effective sealing, even under high pressures, allowing for adaptable and durable operation.

Implementation Method 1

a first cylinder chamber (8) which can be pressurized with compressed air... a second cylinder chamber (10)... The rod seal (4) prevents pressure from acting on the second cylinder chamber (10)

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

The piston rod is slidably mounted in a housing and is pneumatically actuated

Methodology Applied
Scientific EffectPneumatic actuation: Hydraulic Press

Implementation Method 3

This creates an electrical connection between the upper electrode, the bolt, the sheet metal and the lower electrode. Due to the voltage drop between the bolt head and the sheet metal, a lot of heat is generated, which causes the bolt to be welded to the sheet metal

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3646982B1Welding electrode
Publication Date: 2021.05.05 DOCERAM
  • EP3646982B1 patent drawingFigure 1
  • EP3646982B1 patent drawingFigure 2
  • EP3646982B1 patent drawingFigure 3

AI summary

The invention relates to a welding electrode comprising a housing (1) and a piston rod (2) slidably mounted in the housing (1), wherein the piston rod (2) is guided in a sliding bearing (5) and has a piston (7) guided in a cylinder chamber (8) of the housing (1), and wherein a rod seal (4) is arranged in the housing (1), which is penetrated by the piston rod (2) and seals the cylinder chamber (8). The welding electrode according to the invention is characterized in that the rod seal (4) is supported on a first projection of the housing and that the sliding bearing (5) is supported on at least a second projection of the housing. The welding electrode according to the invention exhibits particularly high operational reliability and service life.