| 摘要 |
PURPOSE:To reduce thermal radiation from a target plate to a stator coil and an insulation tube by a method in which the bottom surface facing the target plate of a bottomed cylindrical rotor is made to incline so that the central part comes nearer the target plate side than the peripheral part while the diameter of the peripheral part is bigger widened into the brim shape than the cylindrical part diameter. CONSTITUTION:A brim 14 projected in the disc shape thicker than the diameter of the cylindrical part of a rotor 4a to the side of the bottom part of the rotor 4a is provided en bloc with the rotor, while the inclined surface 15 is provided on the side facing a target plate 5 of the brim 14. The outer diameter of the brim 14 is made thicker at least than the inner diameter of an insulation tube attached to a stator coil provided outside a peripheral receptacle 1 in order to screen thermal radiation from the target plate. Thereby, the thermal radiation from the target plate 5 to the side, wherein the stator coil is located, is screened by the brim 14 so as to reduce temperature rise of the insulation tube and the stator coil and the thermal radiation from the target plate 5 to the brim 14 is reflected outside the target plate 5 by the inclined surface 15 thus reducing heat returning to the target plate. |
