Hollow Frame Welding With Internal Cooling for Shape Accuracy

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Solution Overview

Problem

Existing methods for producing frame structures with bent portions and connecting members face challenges in maintaining geometrical positional accuracy due to thermal distortions during welding, leading to difficulties in achieving high accuracy and design shape conformity.

Innovation Solution

A method involving a welding step where connecting members are welded to a hollow frame member with a bent portion, followed by a cooling step where a cooling medium is introduced into the hollow member through one end, with both steps repeated for each connecting member to control thermal distortion and maintain accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If connecting members are welded to the hollow member, then the number of components is reduced and weight is decreased, but thermal distortion occurs during welding causing geometrical positional accuracy to deteriorate

Engineering Contradiction:

Improveweight of frame structureVSAvoidgeometrical positional accuracy

Core Design Contradiction:

Weight of stationary objectVSManufacturing precision

Solution Approach 1:

The hollow member is pre-bent to a predetermined degree in the opposite direction of the expected thermal distortion before welding. This preliminary action creates a compensatory deformation that counteracts the thermal distortion that will occur during subsequent welding operations, ensuring the final geometrical positional accuracy is maintained while still allowing welding to reduce component weight

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The bending degree of the hollow member is changed as a controllable parameter to compensate for thermal distortion. By adjusting the pre-bending degree based on the number and position of connecting members to be welded, the method dynamically changes the physical state of the hollow member to achieve both weight reduction through welding and maintenance of geometrical positional accuracy

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If bending is conducted using a press or bender to obtain dimensional accuracy, then the shape accuracy is improved, but spring back occurs causing large deformation and making it difficult to maintain accuracy within given range

Engineering Contradiction:

Improvedimensional accuracy of bent portionVSAvoidshape stability after bending

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The hollow member is bent to a predetermined degree that intentionally exceeds the target shape in the opposite direction of expected spring back. This preliminary anti-action creates a compensatory deformation that counteracts the spring back that will occur after bending, ensuring the final shape stability is maintained while still achieving the required dimensional accuracy

Inventive Principle:

Principle #9Preliminary anti-action

3Adaptability or versatility

If multiple connecting members are welded to the hollow member, then the frame structure functionality is improved, but thermal distortions accumulate making it difficult to produce highly accurate shape

Engineering Contradiction:

Improveframe structure functionalityVSAvoidshape accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The hollow member is pre-bent to a predetermined degree that compensates for the cumulative thermal distortion expected from welding multiple connecting members. This preliminary action is calculated based on the number, position, and welding conditions of all connecting members to be attached, creating a compensatory deformation that counteracts the accumulated thermal distortion and maintains final shape accuracy while enabling multi-functional frame structure

Inventive Principle:

Principle #10Preliminary action

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 method enables the production of frame structures with high accuracy and reduced thermal distortion, ensuring that the final product closely resembles the design shape while minimizing the need for extensive shape correction.

Implementation Method 1

a cooling step in which after the welding step, a cooling medium is introduced into the inside of the hollow member through an end of the hollow member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12325060B2Method for producing frame structure

Publication Date: 2025.06.10 KOBE STEEL LTD

AI summary

A method for producing a frame structure contains a hollow member having a curved and long shape, and a plurality of connecting members welded to the hollow member along a longitudinal direction of the hollow member. Each of the connecting members is welded to the hollow member, and a cooling medium is introduced into the inside of the hollow member through an end of the hollow member after the welding. The welding and the introducing are conducted repeatedly in the number of the connecting members.