Welding method and device

Abstract

A TIG welding device ( 10 ) includes a welding robot ( 11 ), robot control device ( 12 ), welding torch ( 13 ), welding control device ( 14 ), gas feeder ( 15 ), and a height detection device ( 16 ). The welding torch ( 13 ) is set at a reference position, and the height detection device ( 16 ) detects the respective heights of two tip parts ( 4 e ). The robot control device ( 12 ) drives the welding robot ( 11 ) such that a torch electrode ( 13 c ) of the welding torch ( 13 ) abuts on central part of the higher tip part ( 4 e ). When the torch electrode ( 13 c ) is moved toward the reference position while power is supplied to the torch electrode ( 13 c ), and inert gas flows in the periphery of the torch electrode ( 13 c ), arc (AC) is generated in a gap between the tip parts ( 4 e ) and the torch electrode ( 13 c ). The overall two tip parts ( 4 e ) are melted and welded by this arc (AC).

1 . A welding method for arc welding a first workpiece and a second workpiece by use of an energized electrode, the welding method comprising:
 a first step of detecting one of the first workpiece and the second workpiece, the one having a shorter distance from a tip surface to be welded to a tip of the electrode;   a second step of abutting the tip of the electrode on the tip surface of the one detected in the first step; and   a third step of generating an arc by separating the tip of the energized electrode from the tip surface of the one detected in the first step, after the second step, and arc welding the first workpiece and the second workpiece.   
     
     
         2 . The welding method according to  claim 1 , wherein
 in the third step, the tip of the energized electrode is displaced so as to be separated from the tip surface of the one detected in the first step, and approach the other to generate the arc.   
     
     
         3 . The welding method according to  claim 1 , wherein
 in the second step, the tip of the electrode is made to abut on a central part of the tip surface of the one detected in the first step.   
     
     
         4 . The welding method according to  claim 2 , wherein
 in the second step, the tip of the electrode is made to abut on a central part of the tip surface of the one detected in the first step.   
     
     
         5 . A welding device for arc welding a first workpiece and a second workpiece by use of an electrode, the welding device comprising:
 a detection unit configured to detect one of the first workpiece and the second workpiece, the one having a shorter distance from a tip surface to be welded to a tip of the electrode;   a displacement unit configured to displace the electrode;   a driving control unit configured to drive the displacement unit so as to abut the tip of the electrode on the tip surface of the one detected by the detection unit;   an energization control unit configured to start energization to the electrode; and   a welding control unit configured to generate an arc by driving the displacement unit such that the tip of the electrode energized by the energization control unit is separated from the tip surface of the one detected by the detection unit, and to arc weld the first workpiece and the second workpiece.