Floating double-shaft shoulder friction stir welding tool and method for space welding

Abstract

The invention discloses a floating double-shaft shoulder friction stir welding tool and a method for space welding. The tool comprises a stirring head and a sleeve; at least two rolling bearings are arranged on a connecting shaft of the stirring head; each rolling bearing is connected with the connecting shaft of the stirring head through a locking bolt; U-shaped grooves in clearance fit connection with the rolling bearings are axially formed in the side wall of the sleeve; the length L2 of the U-shaped grooves is larger than the positioning distance L1 of the rolling bearings; an adjusting bolt in threaded connection with the connecting shaft of the stirring head is inserted in the top center of the sleeve; the adjusting bolt is sleeved with a first limiting spring and a second limiting spring; the first limiting spring is positioned in the sleeve; the second limiting spring is positioned out of the sleeve; and the adjusting bolt is screwed to change relative positions of the connecting shaft of the stirring head and the sleeve so as to realize adjustment of the pressing degree of the first limiting spring and the second limiting spring. The tool is simple and reliable in structure, easy to manufacture and excellent in use effect, and can effectively realize floating welding and space all-position welding.

Description

technical field [0001] The invention relates to the technical field of friction stir welding equipment, in particular to a floating double-shouldered friction stir welding tool and method for space welding. Background technique [0002] Friction stir welding is a solid phase joining technology, which has significant advantages such as high welding quality, small welding deformation, and no environmental pollution. This technology is considered to be the preferred welding technology for low melting point metals such as aluminum alloys. However, since conventional single-shaft shoulder friction stir welding needs to use a backing plate to rigidly support the workpiece to be welded, the welding of hollow parts cannot be realized. To solve this problem, double shoulder friction stir welding uses upper and lower shoulders for welding, wherein the lower shoulder replaces the backing plate to support the workpiece to be welded, so that the hollow parts can be welded. At the same t...

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Problems solved by technology

[0003] However, there are still some problems that need to be solved urgently in the existing floating double-shaft friction stir welding technology: (1) The stirring head and the sleeve of the prior art adopt a key and a keyway to cooperate, as disclosed in the Chinese patent with the announcement number CN204621349U A floating double-shouldered friction stir welding tool. During the friction stir welding process, the stirring head bears a large torque, which causes a large friction force on the contact surface between the key and the keyway, hinders the relative sliding between the key and the keyway, and causes Floating welding cannot be realized; (2) The existing technology still has certain difficulties in welding at all positions in space. For example, when performing horizontal welding or vertical welding, the stirring head, key and keyway are parallel to the ground, and the stirring head cuts into the workpiece to be welded Before, it is in a free sliding state parallel to the ground direction and cannot be positioned, which makes it difficult for the subsequent stirring head to cut into the workpiece accurately for welding; while in flat welding or overhead welding, the stirring head, key and keyway are perpendicular On the ground, due to gravity, the stirring head will slide down freely to the bottom dead center of the keyway stroke or even fall off before cutting into the workpiece to be welded, resulting in the stirring head being unable to continue to float downward after cutting into the workpiece to be welded or even unable to weld

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