Vacuum pump including magnetic bearing and motor bearing operable as radial magnetic bearing, motor, and thrust magnetic bearing

A vacuum pump comprising:

• a rotary body including a rotary shaft, the rotary shaft having a first end and a second end, the rotary shaft extending in an axial direction thereof, a blade support connected to the first end of the rotary shaft, the blade support having a shape extending such that an inner diameter thereof increases from the first end side toward the second end side in the axial direction of the rotary shaft, and a rotor blade provided on an outer peripheral surface of the blade support;
• and
• a rotation mechanism including a motor configured to rotationally drive the rotary body, first and second radial magnetic bearings each configured to support the rotary body in a radial direction of the rotary shaft, and a thrust bearing configured to support the rotary body in the axial direction;
• wherein
• the rotation mechanism includes:
• a magnetic bearing unit provided around the rotary shaft between the rotary shaft and the blade support, the magnetic bearing unit having a first outer diameter, the magnetic bearing unit being operable as the first radial magnetic bearing;
• and
• a motor unit provided around the rotary shaft on the second end side of the rotary shaft relative to the magnetic bearing unit, the motor unit having a second outer diameter larger than the first outer diameter, the motor unit being operable as both the motor and the second radial magnetic bearing, wherein
• the thrust bearing includes a thrust magnetic bearing provided around the rotary shaft;
• the thrust magnetic bearing includes a magnet and a thrust coil, both of which are configured to generate magnetic fluxes that pass through the rotary shaft in the axial direction, respectively,
• the magnetic bearing unit is further operable as the thrust magnetic bearing, and
• the magnetic bearing unit includes a first coil configured to form the first radial magnetic bearing, the thrust coil configured to form the thrust magnetic bearing, and a magnet configured to generate the magnetic flux that interacts with both a magnetic flux of the first coil and a magnetic flux of the thrust coil, and the magnet is provided in common with respect to the first coil and the thrust coil.