To provide a structure for a combination pump of small size, enabling pumping to be performed from 1,000 mbar down to 10-8 mbar normally required in some kinds of industries, and suitable for being integrated into vicinity of a vacuum enclosure or a processing chamber.
A vacuum pump comprises, in a common pump main body 100: molecular drag pump stages 5 in series with a regenerative pump stages 9. The molecular drag pump stages 5 comprise a molecular drag rotor 5a including a blind axial cavity 5c open toward the downstream end, and a motor 7 is housed at least in a part in said blind axial cavity 5c. A drive shaft 8 is coupled via its upstream end 8a to the molecular drag rotor 5a, and coupled via its downstream end 8b to a regenerative type rotor 9a. The motor 7 is secured to the central segment of the drive shaft 8.
Akio Ichiiri
Makoto Ono
Katsuma Osaki
Mitsuaki Tsubokura