Fluid machine having screw rotors with a straight portion to be chucked

摘要

A shaft hole 69 in a cast rotor main body 67 has a hollow space 75 and an opening 79 in a tooth trace 73 formed by using a core. A hollow screw rotor 35 is formed by fixing a rotor shaft 47 in this shaft hole 69. A straight portion 81 to be chucked at the time of machining is formed at the inner peripheral side of the opening 79.