JPH0538388U - Vacuum pump - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is to increase the number of stages of blades through which molecules such as gas and moisture pass without increasing the size of the pump, and to improve the flow rate and compression ratio of molecules such as gas and moisture in the pump. The purpose is to increase. [Constitution] The vacuum pump of the present invention is provided with a gas transfer means composed of blades 5, 6 and the like between the casing 1 and the rotor 4, and between the cylindrical portion 4a of the rotor 4 and the inner cylinder 7. Also has a configuration in which a gas transfer means constituted by the wings 24, 25 and the like is provided. [Effect] According to the vacuum pump of the present invention, the number of blade stages through which molecules such as gas and moisture pass can be increased without increasing the size of the pump to increase the flow rate and compression ratio of molecules such as gas and moisture in the pump. Can be large.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vacuum pump that evacuates a vacuum chamber or the like.

[0002]

[Prior Art]

 Conventionally, for example, when manufacturing an IC product or the like, each process is performed in each work chamber, and when one process is completed in one work chamber, the work piece is transferred to the next work chamber. Here, for example, in one working room, it may be necessary to evacuate this room (vacuum chamber), and in this case, a vacuum pump was used.

As such a vacuum pump, for example, there is an all-blade type turbo molecular pump as shown in FIG. In the figure, reference numeral 101 is a casing, and a suction inlet portion 102 and a discharge outlet portion 103 are formed in the casing 101. A rotor 104 is housed in the casing 101, and rotor blades 105 are formed on the rotor 104 toward the inner peripheral wall surface of the casing 101. A stator blade 106 is attached to an inner peripheral wall surface of the casing 101 so as to face the rotor blade 105. The rotor 104 is rotated by a motor 107 housed in the casing 101, and the rotor blades 105 rotate at a high speed relative to the stator blades 106.

A rotor shaft 112 is fixedly mounted on the rotor 104, and the rotor shaft 112 is magnetically levitated by an axial electromagnet 113 and a radial electromagnet 114 and is rotatably supported. Further, when the rotor shaft 112 that is magnetically levitated is not normally supported by the electromagnets 113 and 114 and falls down, protective bearings 115 and 116 are provided on the fixed member side to rotatably support and protect the rotor shaft 112. However, the protective bearings 115 and 116 are provided so as not to come into contact with the rotor shaft 112 during steady rotation of the rotor shaft 112.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In such a conventional turbo molecular pump, it is desirable to increase the number of blade stages as much as possible in order to increase the flow rate and the compression ratio. This is because the gas molecules from the vacuum chamber pass through many blades and are gradually compressed. However, unnecessarily increasing the number of stages of the blades causes the problem of increasing the size and weight of the pump. Then, this invention makes it a subject to solve such a problem.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a substantially cylindrical casing, a substantially cylindrical inner cylinder arranged on the axis of the casing, and a rotor shaft rotatably driven on the axis of the inner cylinder. An all-wing type rotor provided with a rotor having a substantially cylindrical tubular portion between the casing and the inner cylinder, and a gas transfer means provided with a blade portion provided between the casing and the rotor. In the vacuum pump, a gas transfer means similar to the gas transfer means is provided between the inner cylinder and the cylindrical part of the rotor.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a turbo molecular pump according to an embodiment of a vacuum pump according to the present invention. First, the configuration will be described. In the figure, reference numeral 1 is a casing of a turbo molecular pump, and this casing 1 has a substantially cylindrical shape as a whole, and an opening of a working chamber (not shown) as a vacuum chamber is provided above the casing 1. A suction port 2 is formed to be connected to the discharge port 3, and a discharge port 3 is formed in the lower base 13 of the casing 1. A rotor 4 is housed in the casing 1 in the axial direction, and a plurality of rotor blades 5 extending toward the inner wall surface of the casing 1 are formed radially outside the rotor 4, and the rotor blades 5 are formed. Multiple 5 are formed in multiple stages in the axial direction of the rotor 4. On the inner peripheral wall surface of the casing 1, a plurality of stator blades 6 formed in the same manner as the rotor blades 5 extend inwardly of the radius of the rotor 4 and are arranged so as to alternately overlap the rotor blades 5. .. A cylindrical inner cylinder 7 is provided inside the rotor 4, and the rotor 4 has a cylindrical cylinder portion 4 a between the inner cylinder 7 and the casing 1. A rotor blade 24 is formed on the inner side of the cylindrical portion 4a together with the rotor blade 5 on the outer side thereof. Further, a plurality of stator blades 25 formed in the same manner as the rotor blades 24 are arranged on the outer circumference of the inner cylinder 7 provided inside the rotor 4 so as to alternately overlap the rotor blades 24. ing.

When the rotor blades 5 and 24 provided on the rotor 4 rotate at a relatively high speed with respect to the stationary stator blades 6 and 25, molecules such as gas and moisture in the working chamber are sucked into the suction port. When jumping into the portion 2, the rotor blades 5, the stator blades 6, the rotor blades 24, and the stator blades 25 are compressed and conveyed, and then discharged from the discharge port 3.

On the other hand, a rotor shaft 8 is arranged on the axial portion of the inner cylinder 7 so as to rotate integrally with the rotor 4. Inside the inner cylinder 7, the rotor shaft 8 is rotationally driven at a high speed of about 20,000 to 90,000 rpm to rotate the rotor blades 5 and 24 relative to the stator blades 6 and 25, and the rotor shaft 8. A semi-radial electromagnet 10 that magnetically levitates in the radial direction and rotatably supports it without contact, and an axial electromagnet 11 that magnetically levitates the rotor shaft 8 in the axial direction via an armature disk 12 and rotatably supports it without contact. It is provided. In addition, at the upper and lower ends of the inner cylinder 7, it is possible to prevent the rotor shaft 8 rotating at a high speed from being directly supported by the electromagnets 10 and 11 and not directly touching the inner cylinder 7 when the rotor shaft 8 falls down. Thus, first and second protective bearings 21 and 22 that rotatably support and protect the rotor shaft 8 are provided.

Next, the operation will be described. When it is desired to empty the working chamber (vacuum chamber) by the turbo molecular pump, first, the motor 9 is started to drive the rotor 4 to rotate, and the rotor blades 5 and 24 are stationary with respect to the stationary stator blades 6 and 25. Rotate at relatively high speed. As described above, when the rotor blades 5 and 24 rotate relative to the stator blades 6 and 25, when molecules such as gas and moisture in the working chamber jump into the suction port portion 2, the rotor and the stator blade group 5, It is discharged from the discharge port portion 3 through 6, 24, 25 and further through the exhaust passage 27. At this time, molecules such as gas and water are transported by the rotor blades 5 and the stator blades 6 along the path outside the cylindrical portion 4a of the rotor 4, and then, they wrap around the lower end of the cylindrical portion 4a of the rotor 4. After being conveyed by the rotor blades 24 and the stator blades 25 along the path inside the cylindrical portion 4a, the exhaust gas is discharged from the discharge port portion 3 through the exhaust passage 27. In this way, molecules such as gas and water are added to be conveyed by the rotor blades 5 and the stator blades 6 outside the cylindrical portion 4a of the rotor 4, and the rotor blades 2 4 inside the cylindrical portion 4a of the rotor 4 are added. And the stator blades 25, the number of blades through which molecules such as gas and water pass is increased without increasing the size of the pump to increase the flow rate and compression ratio of molecules such as gas and water in the pump. can do.

[0011]

[Effect of the device]

 As explained above, according to the vacuum pump of the present invention, the flow rate of molecules such as gas and water in the pump is increased by increasing the number of blade stages through which molecules such as gas and water pass without increasing the size of the pump. The compression ratio can be increased.

[Brief description of drawings]

1 is an overall sectional view showing an embodiment of a vacuum pump according to the present invention.

FIG. 2 is an overall cross-sectional view showing a conventional vacuum pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 4 Rotor 4a Cylindrical part 5 and 24 Rotor blade (gas transfer means) 6 and 25 Stator blade (gas transfer means) 7 Inner cylinder 8 Rotor shaft

Claims (1)

[Scope of utility model registration request] 1. A substantially cylindrical casing, a substantially cylindrical inner cylinder arranged at an axial portion of the casing, a rotor shaft rotatably supported by the axial portion of the inner cylinder, and the casing and the inner cylinder. A rotor having a substantially cylindrical tube portion between and,
A full-blade type vacuum pump provided with a gas transfer means which is provided between the casing and the rotor and is constituted by a blade part, and the same as the gas transfer means between the inner cylinder and the cylinder part of the rotor. A vacuum pump characterized by being provided with the gas transfer means.