To prevent deformation of an inner ring of a ball bearing caused by fastening a nut too tightly in a rotor mounting structure for a molecular pump in which a rotary shaft is inserted in a shaft hole of a rotor center, the rotary shaft is pivotally supported by the ball bearing, and the rotor and the rotary shaft are fastened and fixed by a bolt or a nut.
In this rotor mounting structure, a bush 3 having a stepped central through-hole 3a comprising a small diameter hole 3a1 and a large diameter hole 3a2 is fitted with a large diameter hole 1c2 of a stepped hole 1c of a rotor 1; a male screw part 2a is formed at a tip end of the rotary shaft 2; a first shaft part 2b fitted in the small diameter hole 3a1, a second shaft part 2c fitted in the large diameter hole 3a2, and a third shaft part 2d having a diameter larger than that of the second shaft part 2c are sequentially connected in the male screw part 2a of the rotary shaft 2; a stepped part between the small diameter hole 3a1 and the large diameter hole 3a2 of the bush 3 is abutted on a stepped part 2bc between the first shaft part 2b and the second shaft part 2c; and the rotor 1 and the rotary shaft 2 are fastened and fixed by the nut 4.
| WO/2022/219029 | REFINED SNIFFING-BASED LEAK DETECTION SYSTEM |
| JPH07293563 | DRIVE CONTROL DEVICE FOR ROTATING DEVICE SUPPORTING ROTOR ON MAGNETIC BEARING |
| JP2022520976 | Vacuum pump |
YOSHIDA SORO
KURIOKA HIROYUKI
