Shaft structure in screw rotor of screw fluid assembly

Abstract

A rotor 1 forming screw teeth is projectingly provided at its outer end 2 on the axis thereof with a center shaft 3. The center shaft 3 is provided at its outer end 4 with a smaller-diameter shaft 5 or a concaved fitting hole. A separate rotor shaft 6 which is to be fitted over the smaller-diameter shaft 5 or fitted into the concaved fitting hole is provided with another concaved fitting hole 7 or smaller-diameter shaft. A metal shaft around which synthetic resin is molded is formed at its peripheral surface with a spiral groove or corrugated groove in the opposite revolutional direction with respect to the revolutional direction of the screw rotor. The spiral groove is formed with smooth arc curved line connecting profiles of adjacent grooves. The shaft is provided with a step, and synthetic resin is molded around the shaft surface to form a screw rotor.

Dependencies are inferred from the claim text.