ROOTANOSEIZOHOHO

摘要

PURPOSE:To attempt improvement in accuracy of the size of a rotor by covering a metallic shaft provided with a refrigerant flow-through hole penetrating the shaft in axial direction by means of a synthetic resin layer. CONSTITUTION:A screw rotor 1 comprises a metallic shaft 2 made of iron steel etc. and a synthetic resin layer 3 for coating it. The synthetic resin layer 3 is formed approximately in a cylindrical shape as a whole, with its both end faces orthogonal to the shaft 2 and 4 lines of screw formed on its periphery. The metallic shaft 2 is provided with a coolant flow-through hole 4 for penetrating its center in the axial direction. This refregerant flow-through hole 4 is not necessarily arranged to penetrate the shaft 2 along its total length but only necessary to penetrate a portion covered by the synthetic resin layer 3.