| 摘要 |
PURPOSE:To reduce impact force that acts on a robot and improve accuracy of positioning by bringing a movable electrode into contact with a work by low pressure and pressing by high pressing force at the time of welding. CONSTITUTION:When starting welding work, pressure of compressed air from an air source 27 is reduced by a pressure regulator 25 and supplied to a cylinder 9 through a shuttle valve 24 and an air passage 32, and the tip of an electrode 8 is brought into contact at relatively small first set pressure. When it comes into contact with a reinforcing member to which a movable electrode is connected, a solenoid valve 31 for high pressure of a fluid supplying device for pressing 28 is switched by a switching signal from a timer 33 after switching of a solenoid valve 26. Then, compressed air from the air source 27 is supplied to the cylinder 9 without reducing its pressure. At this time, a return passage 30 is opened to the air, and thereby the first and second pistons are pressed by greater pressure. Consequently, pressing is made at the second set pressure which is pressing force of normal welding. |
