Resistance Spot Welding Gun Spindle Design

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Solution Overview

Problem

Existing resistance spot welders face challenges in simplifying the spindle connecting device, leading to increased complexity, size, weight, and cost due to the need for electric insulation and lubrication, while also struggling to maintain a compact design and efficiently manage the secondary circuit and cooling system.

Innovation Solution

A spindle connecting device using highly conductive copper or aluminum gun arms with a cylindrical collar, oilless bearings, and a sealing mechanism to reduce size and weight, eliminating the need for lubrication and simplifying the structure, while allowing for easy reconfiguration to accommodate varying workpiece shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional spindle connecting devices use insulating thrust washers and lubrication mechanisms, then electric insulation and wear resistance are improved, but device complexity, size, and weight increase

Engineering Contradiction:
Improveelectric insulation and wear resistanceVSAvoidspindle connecting device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the insulating thrust washer and lubrication mechanism from the spindle connecting device. Instead, it uses a simple shaft directly connecting the gun arms, relying on the self-lubricating properties of the shaft material (e.g., sintered metal or bronze) to reduce wear without requiring external lubrication systems or insulating components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the material parameters of the shaft by using sintered metal or bronze materials that possess both electrical insulation properties and self-lubricating characteristics. This material selection eliminates the need for separate insulating and lubrication components, simplifying the overall device structure while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If the spindle connecting device includes insulating components and lubrication passages, then electric insulation and durability are improved, but manufacturing cost and device size increase

Engineering Contradiction:
Improvespindle connecting device durabilityVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The patent eliminates insulating components and lubrication passages from the design. The shaft is made from materials that inherently provide both insulation and self-lubrication, removing the need for complex manufacturing processes involving multiple components, assembly steps, and lubrication system maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If the gun arms are made highly conductive for efficient welding, then welding efficiency is improved, but electric insulation requirements increase device complexity

Engineering Contradiction:
Improvewelding efficiencyVSAvoidelectric insulation structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the electrical conduction path from the insulation requirement. The gun arms themselves are made highly conductive for efficient welding, while the shaft connecting them is made from insulating or self-insulating materials. This segmentation allows each component to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

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 results in a more durable, compact, and lightweight resistance spot welder with improved wear resistance and reduced manufacturing costs, enabling efficient welding operations and enhanced welding quality by simplifying the spindle connecting device and integrating the gun arms for adaptable design.

Implementation Method 1

a bearing (oilless bearing) is inserted between the shaft and the collar

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a seal member is fitted in an annular groove formed on the outer circumference of the shaft, so as to seal the clearance

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP1839797B1Spot welding gun
Publication Date: 2016.03.30 DENGENSHA TOA CO LTD
  • EP1839797B1 patent drawingFigure 1
  • EP1839797B1 patent drawingFigure 2
  • EP1839797B1 patent drawingFigure 3~4

AI summary

A resistance spot welder includes: a first plate (4); a second plate (3), rotatably connected to the first plate (4) through a shaft (15), and driven on the shaft (15) by an actuator (M); gun arms (6, 7), removably fixed on and electrically insulated with the first and second plates (4,3), respectively, and electrode tips (E1, E2), confronting each other, and fixed on the gun arms (6, 7), respectively.