Arcuate Protrusion for Vehicle Door Frame Resistance Welding

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Solution Overview

Problem

The existing vehicle door frame welding process often results in spatter due to the concentration of electric current on corner portions during resistance welding, leading to unstable weld quality.

Innovation Solution

A vehicle door frame design featuring an inner member with a protrusion having an arcuate tip end that avoids corner portions, allowing for even heating and melting during resistance welding, thereby preventing spatter and ensuring stable joint quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the protrusion tip end includes a corner portion for resistance welding, then the welding structure is simple to manufacture, but the electric current concentrates on the corner portion causing spatter and unstable weld quality

Engineering Contradiction:
Improvewelding structure manufacturingVSAvoidweld quality stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The protrusion tip end is designed with an arcuate cross-section instead of a corner portion, creating a curved surface that distributes electric current evenly during resistance welding. This curvature prevents current concentration at sharp edges, eliminating spatter and ensuring stable weld quality while maintaining manufacturing simplicity

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the protrusion tip end has a corner portion, then the welding process is faster, but spatter occurs causing rework and reducing overall productivity

Engineering Contradiction:
Improvewelding speedVSAvoidspatter
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The arcuate tip end design eliminates spatter by distributing electric current uniformly across the curved surface, preventing metal droplet dispersion. This allows continuous welding operations without interruption for cleanup or rework, maintaining high productivity while eliminating the harmful spatter effect

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the protrusion tip end is arcuate, then spatter is prevented and weld quality is stable, but the manufacturing process becomes slightly more complex

Engineering Contradiction:
Improveweld quality stabilityVSAvoidprotrusion shape complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protrusion tip end geometry is optimized with specific arcuate parameters (radius, curvature profile) that achieve current distribution and weld quality goals. By carefully selecting and controlling these geometric parameters, the design attains reliable weld quality while keeping the manufacturing process straightforward through standard forming operations

Inventive Principle:
Principle #35Parameter changes

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 arcuate tip end protrusion ensures stable welding by preventing spatter and maintaining consistent weld quality, enhancing the tensile strength and efficiency of the welding process.

Implementation Method 1

the protrusion can be melted by heating by concentration of electric current during resistance welding

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the phenomenon, which is referred to as spatter, may be caused in which the metal melted by welding disperses and is solidified to granulate

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2789483B1Vehicle door frame and inner member for vehicle door frame
Publication Date: 2019.11.20 AISIN SEIKI KK
  • EP2789483B1 patent drawingFigure 1~2
  • EP2789483B1 patent drawingFigure 3~4
  • EP2789483B1 patent drawingFigure 5A~5D

AI summary

A vehicle door frame, which forms the window frame of a vehicle door, includes an outer member and an elongated inner member. The outer member forms a glass-run housing portion. The inner member includes a body portion for forming the framework of the window frame and is coupled to the outer member. The outer member includes an edge portion, which forms a part of the glass-run housing portion, and a folded portion, which includes a substantially U-shaped cross section. The folded portion is provided at the edge portion, and includes an opening, which opens in an inward direction of the vehicle. The inner member includes an extended portion, which extends in an outward direction of the vehicle from the body portion, and an edge portion, which is provided at the extended portion. The edge portion of the extended portion is inserted into the opening of the folded portion. The edge portion of the extended portion includes a distal end surface. A protrusion is formed on the distal end surface. The protrusion protrudes in the outward direction of the vehicle and is located at a predetermined position of the inner member in the longitudinal direction. The folded portion has a facing portion that faces the distal end surface. The protrusion can be melted by heating by the concentration of electric current during resistance welding and is configured to pressurize and join the distal end surface and the facing portion of the folded portion to each other. The protrusion includes a tip end, which has an arcuate cross section protruding in the outward direction of the vehicle.