| 摘要 |
PURPOSE:To increase mechanical strength of a screw rotor and decrease its thermal deformation, by using a material of excellent mechanical strength for a shaft part and a material of small thermal expansion coefficient for a rotor toothed part. CONSTITUTION:Rotor shaft parts 22, 23 are prepared by a material of carbon steel or cast iron or the like with large mechanical strength while rotor toothed parts 24, 25 are prepared by a material of nitrified system ceramic or the like with a small thermal expansion rate. Further elastic members 26, 27 are provided between the shaft part and the toothed part, and the shaft part is combined with the toothed part by said elastic member. Accordingly, a screw rotor of large mechanical strength further with a small thermal expansion rate can be prepared. |
