Turbo-molecular pump

1. A turbo-molecular pump comprising:

a shaft to be rotatably driven by a motor;

a pump rotor;

multiple bolts penetrating the pump rotor from a pump suction port side to fasten the pump rotor to a pump suction port side end portion of the shaft; and

a seal member configured to seal a clearance between fastening surfaces of the pump rotor and the shaft or a clearance between each bolt and the pump rotor, wherein

the seal member is an O-ring seal

arranged in a seal groove formed by a tapered surface formed at a pump suction port side edge of a bolt hole of the pump rotor, an outer peripheral surface of each bolt, and a bolt head of each bolt, and

configured to contact each of the tapered surface, the outer peripheral surface, and the bolt head to seal the clearance between each bolt and the pump rotor.

2. A turbo-molecular pump comprising:

a shaft to be rotatably driven by a motor;

a pump rotor;

multiple bolts penetrating the pump rotor from a pump suction port side to fasten the pump rotor to a pump suction port side end portion of the shaft;

a seal member configured to seal a clearance between fastening surfaces of the pump rotor and the shaft or a clearance between each bolt and the pump rotor, and

a rotor balance correction member fixed to the pump suction port side of the pump rotor,

wherein the bolts penetrate the rotor balance correction member and the pump rotor from the pump suction port side to fasten the rotor balance correction member and the pump rotor to the pump suction port side end portion of the shaft, and

the seal member is an O-ring seal

arranged in a seal groove formed by a fastening surface of one of the rotor balance correction member or the pump rotor, a tapered surface formed at an edge of a bolt hole of a fastening surface of the other one of the rotor balance correction member or the pump rotor, and an outer peripheral surface of each bolt, and

configured to contact each of the fastening surface of the one of the rotor balance correction member or the pump rotor, the tapered surface, and the outer peripheral surface to seal the clearance between each bolt and the pump rotor.

3. A turbo-molecular pump comprising:

a shaft to be rotatably driven by a motor;

a pump rotor;

multiple bolts penetrating the pump rotor from a pump suction port side and into a pump suction port side end portion of the shaft to fasten the pump rotor to the pump suction port side end portion of the shaft, fastening surfaces between the pump rotor and the shaft being positioned on a back pressure side of the pump rotor communicating with an exhaust port; and

a seal member configured to seal a clearance between fastening surfaces of the pump rotor and the shaft or a clearance between each bolt and the pump rotor and to prevent leakage of a gas from the back pressure side to a suction port side,

wherein

the seal member is an O-ring seal attached to an inner periphery of a bolt hole of the pump rotor or an outer periphery of a bolt shaft of each bolt.

4. A turbo-molecular pump comprising:

a shaft to be rotatably driven by a motor;

a pump rotor;

multiple bolts penetrating the pump rotor from a pump suction port side and into a pump suction port side end portion of the shaft to fasten the pump rotor to the pump suction port side end portion of the shaft, fastening surfaces between the pump rotor and the shaft being positioned on a back pressure side of the pump rotor communicating with an exhaust port; and

a seal member configured to seal a clearance between fastening surfaces of the pump rotor and the shaft or a clearance between each bolt and the pump rotor and to prevent leakage of a gas from the back pressure side to a suction port side,

wherein

the seal member is arranged to collectively surround the multiple bolts to seal the clearance between the fastening surfaces of the pump rotor and the shaft, and

the seal member is a plate-shaped metal gasket.

5. A turbo-molecular pump comprising:

a shaft to be rotatably driven by a motor;

a pump rotor;

multiple bolts penetrating the pump rotor from a pump suction port side and into a pump suction port side end portion of the shaft to fasten the pump rotor to the pump suction port side end portion of the shaft, fastening surfaces between the pump rotor and the shaft being positioned on a back pressure side of the pump rotor communicating with an exhaust port; and

a seal member configured to seal a clearance between fastening surfaces of the pump rotor and the shaft or a clearance between each bolt and the pump rotor and to prevent leakage of a gas from the back pressure side to a suction port side,

wherein

the seal member is provided to surround each of the multiple bolts to seal the clearance between the fastening surfaces of the pump rotor and the shaft, and

the seal member is a plate-shaped metal gasket.