Friction Stir Welding Tool With Intermediate Shoulder Against Shaft Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Friction stir welding tools face durability issues due to resistance forces that cause bending of the stirring shaft, especially when working with thick double skin members, leading to reduced tool longevity and increased operational costs.
Innovation Solution
The friction stir welding tool incorporates an intermediate shoulder with wheels and whirl-stop portions that prevent the stirring shaft from inclining, thereby reducing bending and enhancing durability by stabilizing the tool during the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If friction stir welding is performed at two positions simultaneously using upper and lower shoulders, then productivity is improved, but the stirring shaft is subjected to large resistance forces and rotational moments causing bending and reduced durability
Solution Approach 1:
The tool is divided into three separate shoulder components: upper shoulder, intermediate shoulder, and lower shoulder. These segmented shoulders can be attached to or separated from the stirring shaft independently, allowing the tool to perform single-position welding when durability is concerned and dual-position welding when productivity is prioritized.
Solution Approach 2:
The shoulders are designed to be dynamically attachable and detachable from the stirring shaft. This dynamic configuration allows the operator to adjust the tool setup based on whether single-position or dual-position welding is required, optimizing both productivity and durability as needed.
2Strength
If the thickness of the double skin member is increased, then the structural strength is improved, but the length between upper and lower gaps increases causing larger rotational moments and stirring shaft bending
Solution Approach 1:
The intermediate shoulder acts as a segmentation element positioned between the upper and lower shoulders. This intermediate component helps distribute and reduce the rotational moments generated during welding of thick double skin members, preventing excessive bending of the stirring shaft while maintaining the ability to weld thicker materials.
Solution Approach 2:
The intermediate shoulder serves as an intermediary component between the upper and lower shoulders. It provides structural support and helps balance the forces acting on the stirring shaft during welding of thick materials, reducing the overall bending moment while enabling the welding of stronger, thicker workpieces.
3Force
If resistance force acts on the stirring shaft during dual-position welding, then the joining force is improved, but the stirring shaft bends reducing tool longevity
Solution Approach 1:
By segmenting the shoulder structure into three separate components, the resistance forces acting during dual-position welding are distributed across multiple attachment points rather than concentrated on a single rigid structure. This segmentation reduces the bending moment on the stirring shaft while maintaining the necessary joining force.
Solution Approach 2:
The intermediate shoulder acts as a cushioning element that absorbs and distributes the resistance forces before they reach the stirring shaft. This prior cushioning effect protects the stirring shaft from excessive bending forces during operation, extending tool service life.
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 effectively suppresses shaft inclination and bending, improving the tool's durability and allowing for more efficient and cost-effective friction stir welding operations, even with thicker materials.
Implementation Method 1
an intermediate shoulder arranged around the stirring shaft so as to be located between the upper shoulder and the lower shoulder
Implementation Method 2
Friction stir welding is conventionally used when end portions of plates are made to face each other and are joined to each other
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
There is provided a friction stir welding tool and a friction stir welding method, by each of which influence on durability of the friction stir welding tool is suppressed even when resistance force generated when the friction stir welding tool moves for joining acts on facing end portions of workpieces which portions are located close to an attachment side of the friction stir welding tool. The friction stir welding tool includes: a stirring shaft; a first shoulder portion provided so as to be unrotatable relative to the stirring shaft and configured to rotate together with the stirring shaft when the stirring shaft rotates; a second shoulder portion provided so as to be unrotatable relative to the stirring shaft and configured to rotate together with the stirring shaft when the stirring shaft rotates; and a third shoulder portion attached around the stirring shaft so as to be located between the first shoulder portion and the second shoulder portion. The third shoulder portion includes an inclination preventing portion configured to prevent inclination of the stirring shaft by contacting the workpieces to receive reaction force from the workpieces when the stirring shaft is made to move along joining lines.