Coaxial Resistance Welding Electrodes for Uniform Current Flow
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Solution Overview
Problem
Conventional spot welding devices lack an external ground, leading to unstable current flow paths and non-uniform welding quality due to the absence of separate positive and negative electrodes, which affects the efficiency and safety of the welding process.
Innovation Solution
A welding device with first and second pressing members, both receiving positive and negative currents respectively, are aligned coaxially to ensure consistent current flow, and an elastic member maintains a controlled distance between them, while an insulating plate and film prevent grounding, enhancing safety and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional spot welding devices supply current through the vehicle body without separate positive and negative electrodes, then the device structure is simple, but the current flow path becomes unstable and welding quality becomes non-uniform
Solution Approach 1:
The welding device is segmented into separate positive and negative pressing members (electrodes) that are coaxially arranged. The positive pressing member supplies positive current through a positive bus bar, while the negative pressing member supplies negative current through a negative bus bar. This segmentation creates distinct current flow paths for each electrode, ensuring stable and uniform current distribution across the welding interface, thereby achieving consistent welding quality.
2Manufacturing precision
If separate positive and negative electrodes are implemented coaxially, then welding quality uniformity is improved, but the device complexity increases
Solution Approach 1:
The positive and negative pressing members are merged into a single coaxial assembly where the negative pressing member is positioned inside the positive pressing member. Both electrodes are integrated into one welding tool head that can be mounted on a robot arm, allowing simultaneous application of positive and negative currents through a unified structure. This merging reduces the number of separate components and simplifies the overall device architecture while maintaining the benefits of separate current paths.
Solution Approach 2:
The negative pressing member is nested inside the positive pressing member, creating a concentric, coaxial arrangement. The negative electrode is positioned within the hollow interior of the positive electrode, both sharing the same central axis. This nested configuration allows both electrodes to be housed within a single compact welding tool head, reducing device complexity while ensuring stable and uniform current flow through the nested coaxial structure.
3Productivity
If the second pressing part is drawn out to penetrate the first pressing part, then welding efficiency is improved, but the risk of unintended grounding increases
Solution Approach 1:
An insulating plate is introduced as an intermediary element between the positive and negative pressing members. The insulating plate is positioned between the two electrodes to prevent direct electrical contact and unintended grounding. This mediator allows the negative pressing member to be drawn out and penetrate the positive pressing member for efficient welding while maintaining electrical isolation, thereby eliminating the grounding risk associated with the penetrating motion.
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 configuration stabilizes current flow, ensuring reliable and uniform welding quality, increasing efficiency and safety by preventing unintended grounding and maintaining precise control over the welding process.
Implementation Method 1
A transformer is configured to supply a positive (+) current to the first pressing member and a negative (−) current to the second pressing member
Implementation Method 2
The second pressing part may have an elastic member at an outer periphery thereof between the first pressing member and the second pressing member
Implementation Method 3
The first pressing member may have an insulating plate attached thereon between an upper surface of the first pressing member and the elastic member for insulation
Implementation Method 4
The spot welding melts contact portions by heat generated at the contact portions due to electric resistance and bonds the contact portions by applying a pressure thereto
Data Source
AI summary
A welding device of a robot arm includes a welding machine having a first pressing member which includes a cylindrical first pressing part and a second pressing member which includes a second pressing part inserted into a hollow of the first pressing part. A transformer supplies a positive (+) current to the first pressing member and a negative (−) current to the second pressing member. The first and second pressing parts have the same co-axis.