To provide a vacuum pump of high safety capable of balancing a rotary body for a long period, and preventing breakage of the rotary body due to stress concentration.
This vacuum pump comprises a pump case 1 having a gas intake port 2 opened in an upper surface, a rotor shaft 5 rotatably supported in the pump case 1, plural rotor blades 10, 10, etc., integrally formed with an outer wall surface 8a of a rotor 8 in a cylindrical form, contained in the pump case 1, and fixed to the rotor shaft 5, plural stator blades 11, 11, etc., alternately positioned between the rotor blades 10, 10, etc., and fixed in the pump case 1, and a drive motor 9 to rotate the rotor shaft 5. For balancing it, the rotor 8 is held to a headstock 21, and a roughly semispherical balancing hole 16 is formed at a prescribed position in the outer wall surface 8a or an inner wall surface 8b of the rotor 8 using an end mill 30 installed on a tool rest 23 disposed to be tilted to the rotor 8, and having a roughly semispherical tip part 31a.
OKADA TAKASHI
MAEJIMA YASUSHI
KAWANISHI SHINJI
SAKAGUCHI YUKO
OKUDERA SATOSHI
