Double-Acting Rotary Tool for Friction Stir Spot Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Friction stir spot welding with a double-acting rotary tool faces challenges due to material adhesion in the gap between the probe and shoulder member, preventing repeated operations and affecting joint strength and coating quality.
Innovation Solution
A rotary tool with a double-acting structure featuring a small gap at the tip and an enlarged gap at the base, allowing independent axial movement of the probe and shoulder member, and optionally a pressing member, to facilitate material ejection and prevent adhesion, using a combination of small and enlarged gaps to manage material flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a double-acting rotary tool with a gap between the probe and shoulder member is used, then the tool can adapt to different thicknesses of metal plate members and prevent hole formation, but material enters and adheres to the gap causing difficulty in independent operation and preventing repetition of welding operations
Solution Approach 1:
The gap between the probe and shoulder member is designed to be variable rather than fixed. The gap width changes dynamically based on the thickness of the metal plate members being welded, allowing the tool to adapt to different thicknesses while preventing material adhesion through optimized clearance dimensions
Solution Approach 2:
The gap dimensions are optimized as a critical parameter to prevent material adhesion. By controlling the gap width within specific ranges, the invention prevents material from entering and adhering to the gap while maintaining the ability to adapt to different plate thicknesses
2Ease of operation
If material enters the gap between probe and shoulder member, then adhesion occurs preventing repeated operations, but maintaining a gap is necessary for independent movement of components
Solution Approach 1:
The gap dimensions are optimized to specific parameter ranges that prevent material adhesion while allowing independent movement. By controlling gap width and length parameters, the invention enables repeated welding operations without material clogging the gap between components
3Device complexity
If a conventional pin-type tool with integral probe and shoulder is used, then the structure is simple, but a recessed portion (hole) is left after extraction causing liquid accumulation and reduced joint strength
Solution Approach 1:
The tool is segmented into separate probe and shoulder member components that can move independently. This segmentation allows the shoulder member to bury the probe hole by moving ahead and pressing against the friction stir region surface, eliminating the recessed portion that would otherwise cause liquid accumulation and strength problems
Solution Approach 2:
The probe and shoulder member are designed with independent axial movement capability. After spot joining, the shoulder member can move ahead of the probe to press against the friction stir region surface and bury the probe hole, dynamically adapting the tool configuration to eliminate defects
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 tool effectively suppresses material adhesion and accumulation, enabling smooth and repeated friction stir spot welding operations, improving joint quality and extending tool lifespan by managing material entry and ejection through strategically designed gaps and ejection holes.
Implementation Method 1
a shoulder portion formed at the tip of the body of the pin-type tool is pressed onto the stacked portions to generate friction heat between the shoulder portion, the probe and the stacked portions so as to cause a plastic flow of material
Data Source
AI summary
A rotary tool for friction stir spot welding including: a rod-like probe to be inserted into one side of stacked planar portions of plural metal members to be joined while being rotated; and a cylindrical shoulder member which is disposed coaxially outwardly of the probe and which has a shoulder surface to be abutted against the one side of the stacked portions while being rotated, wherein the probe and the shoulder member are individual components and are disposed so as to have a double-acting structure which enable them to move independently in their axial direction, and in which a gap between an inner surface of the shoulder member and an outer surface of the probe is formed to have a small gap on a tip side of the rotary tool and to have an enlarged gap having larger clearance than the small gap on a base portion side thereof.