| 摘要 |
PROBLEM TO BE SOLVED: To improve insulating property, and to ensure the withstand voltage to the trigger voltage by covering a part in contact with a cooling water for at least one of an electrode chuck and a restricted nozzle with an insulation material. SOLUTION: An electrode 2 is fitted to a torch body 1 through an electrode chuck 3. A restricted nozzle 5 is fitted to the torch body 1 so as to surround the electrode 2. A shield gas nozzle 6 to surround the restricted nozzle 5 is fitted to a lower part of the torch body 1. A cooling water passage 8 to communicate with a water-cooled jacket part 5d formed on the restricted nozzle 5 is demarcated in an outer circumferential space of the electrode chuck 3 in the torch body 1. The restricted nozzle 5 comprises a cylindrical part 5a to be locked by an adapter 6b to the torch body 1, and a nozzle chip 5 to be tightened by nuts 5b. An insulation sleeve 7 is fitted to the inner side of the cylindrical part 5a. An insulation material 9 such as a Teflon(R) is coated on an outer circumferential surface of an outer sleeve 3b. |
