Linear Motor Electrode Feed for Resistance Welding

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Solution Overview

Problem

Existing resistance welding devices face challenges in achieving precise and reproducible electrode feed processes due to mechanical gear play, additional mass, and the limitations imposed by routing welding current cables, leading to suboptimal welding results in mass production.

Innovation Solution

The implementation of a linear motor as an electromagnetic direct linear drive eliminates mechanical gear play and reduces wear, enabling precise control and high rigidity, while integrating the welding current conductor into the rotor allows for flexible cable use and eliminates the need for external welding current cables, enhancing the dynamic-mechanical behavior and control of the electrode feed device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a rotary electric motor with mechanical transmission (gear, toothed rack, spindle) is used to generate linear movement in the electrode feed device, then the required linear movement can be achieved, but mechanical gear play, additional mass, and transmission losses occur which deteriorate the dynamic-mechanical behavior and positional accuracy

Engineering Contradiction:
Improvepositional accuracy of electrodeVSAvoidmechanical transmission components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the rotary electric motor with mechanical transmission system with a linear motor that generates linear movement directly through electromagnetic force. The linear motor eliminates gears, toothed racks, and spindles, substituting mechanical transmission with direct electromagnetic actuation. This results in no mechanical gear play, reduced moving mass, and improved dynamic-mechanical behavior while maintaining the required linear movement capability for electrode feeding.

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

2Ease of operation

If welding current cables are routed externally from the welding current source to the movable electrode, then the electrode can be supplied with welding current, but the cables have relatively large mass and are only conditionally flexible which makes it difficult to control the infeed movement of the movable electrode

Engineering Contradiction:
Improvecontrol of electrode infeed movementVSAvoidmass of welding current cable
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent merges the welding current conductor with the rotor of the linear motor. The rotor serves dual functions: generating linear movement through electromagnetic interaction and conducting welding current to the electrode. This integration eliminates the need for separate external welding current cables, reducing the moving mass and improving the controllability of electrode infeed movement while ensuring reliable welding current supply.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If a linear motor is used as an electromagnetic direct linear drive, then mechanical gear play is eliminated and positional accuracy is improved, but the welding current cable must be integrated into the moving parts which adds complexity to the motor design

Engineering Contradiction:
Improvepositional accuracy of electrodeVSAvoidintegration of welding current conductor in rotor
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent designs the rotor to perform multiple functions simultaneously: it acts as the moving component for linear motor operation and as the welding current conductor. This multi-functional design integrates the welding current pathway into the existing motor structure without requiring separate cable management systems. The rotor's dual role simplifies the overall system architecture while maintaining high positional accuracy through direct linear motor actuation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution achieves high positional accuracy and reproducibility in electrode movement, allowing for better follow-up behavior and improved welding results by minimizing mechanical interference and cable-related issues, resulting in more reliable and precise welding processes.

Implementation Method 1

The infeed device (5) has a linear motor (7) as an electromagnetic direct linear drive with which the rotor (17) can be moved along the infeed axis (14) by means of an electromagnetic force

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

resistance welding device... provide the welding current... welding processes

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP3213852B1Resistance welding device
Publication Date: 2019.06.12 OTTO BIHLER HANDELS BET
  • EP3213852B1 patent drawingFigure 1~2
  • EP3213852B1 patent drawingFigure 3

AI summary

The invention relates to a resistance welding device comprising two welding electrodes (9, 11) arranged opposite each other and connected or connectable to a welding power source via a respective power supply path for welding material to be placed between the electrodes (9, 11), wherein at least one first electrode (9) of the two electrodes (9, 11) can be moved relative to the other electrode (11) from an electrode distance position to a welding position by means of a feed device (5) in order to weld material between the electrodes (9, 11), wherein the feed device (5) has an electric motor (7; 107) for moving the first electrode (9), wherein the electric motor (9) is a linear motor with a stator (15; 115) and a rotor (17; 117) guided linearly along a linear axis of motion (14; 114), and wherein the rotor (17;117) the first electrode (9) is designed as a welding current conductive component and for this purpose has a welding current conductor section (23; 123) which is integrated into the power supply path between the welding power source and the first electrode (9).;