| 摘要 |
PURPOSE:To prevent durability from dropping due to damage, etc. off an irradiating cylindrical body by providing a heat cutting-off means against radiation heat from the inside surface of a hole of an object to be quenched, on the outside surface of the laser irradiating cylindrical body inserted into the hole for the purpose of irradiating a laser beam into the hole of the object to be quenched. CONSTITUTION:A laser irradiating cylindrical body 9 is inserted into a a bore for the purpose of irradiating a laser to the surface of the bore 2 of a cylinder block 1. A heat insulating material 12 is wound so as to cover the outside peripheral surface except a window 10 of said laser irradiating cylindrical body 9, and the lower face of the bottom plate. Therefore, a radiation heat from the surface of the bore 2 is cut off, and the radiation heat raising the temperature of the laser irradiating cylindrical body 9 is prevented. |
