Friction Stir Welding Tool With Elastic Shoulder Load Control
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Solution Overview
Problem
Existing joining devices for friction stir welding that perform load control are complex and expensive, making them unsuitable for use with relatively inexpensive machining centers that primarily offer position control.
Innovation Solution
A rotary tool design featuring a stirring pin and a shoulder that are relatively movable, integrated with elastic members to simulate load control, allowing for precise insertion depth and surface finish, even when mounted to a machining center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If load control is implemented using a robot arm joining device, then joining quality and press-fitting depth control are improved, but device complexity and cost increase
Solution Approach 1:
A force detection unit is introduced as an intermediary component between the rotary tool and the control unit. This unit detects the force applied during press-fitting and provides feedback to the control unit, enabling load control without requiring a complex robot arm system. The force detection unit acts as a mediator that translates physical force into controllable signals.
Solution Approach 2:
The control unit receives detection results from the force detection unit and adjusts the pressing amount of the rotary tool accordingly. This closed-loop feedback mechanism enables automatic load control, where the system continuously monitors the applied force and makes real-time adjustments to maintain optimal press-fitting depth and force.
2Device complexity
If position control is used with a machining center, then device cost is reduced, but load control capability and joining quality deteriorate
Solution Approach 1:
The force detection unit provides real-time feedback on the pressing force, allowing the control unit to adjust the pressing amount even when using a simple position-controlled machining center. This feedback mechanism compensates for the lack of inherent load control capability in position-controlled systems.
Solution Approach 2:
The patent replaces complex mechanical load control mechanisms with a combination of force detection and control unit processing. Instead of using a mechanically complex robot arm with inherent load control, the system uses a simpler machining center augmented with force detection and software-based control.
3Device complexity
If the stirring pin and shoulder are fixed relative to each other, then structural simplicity is maintained, but insertion depth control and surface finish quality deteriorate
Solution Approach 1:
The stirring pin and shoulder are designed to be relatively movable rather than fixed. The stirring pin can move in the axial direction relative to the shoulder, allowing dynamic adjustment of the insertion depth based on the detected force and control unit instructions. This dynamic capability enables precise insertion depth control while maintaining overall structural simplicity.
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
Enables load control and improves surface finish through elastic member-assisted insertion depth regulation, reducing burr formation and enhancing welding quality without increasing device complexity or cost.
Implementation Method 1
a first elastic member that biases the assembly toward a distal-end side of the stirring pin relative to the axial direction of the rotary shaft
Data Source
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AI summary
An object of the present invention is to provide a rotary tool, a joining device, and a joining method that can carry out load control while mounted to a machining center. The present invention is characterized by the configuration including: a main body (10) having a fixed unit (11) and a rotary shaft (12); a stirring pin (50) that is arranged on the main body (10) so as to be rotatable and to be movable relative to an axial direction of the rotary shaft (12), and that is inserted into a joint member (2) to perform friction stirring; and a shoulder (60) that is formed separately from the stirring pin (50), that is arranged on the main body (10) so as not to receive a rotary force from the main body (10) but to be movable relative to the axial direction of the rotary shaft (12), and that presses the joint member (2) while in contact with the joint member (2), wherein the stirring pin (50) and the shoulder (60) are mounted to form an assembly (70) so as to be relatively movable and to move integrally in the axial direction of the rotary shaft (12), and the rotary tool further includes a first elastic member (51) that biases the assembly (70) toward a distal-end side of the stirring pin (50) relative to the axial direction of the rotary shaft (12).