JPS6346717Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention is a turbo molecular pump suitable for use in vacuum pumping parts of vacuum equipment that dislikes vibrations, such as scanning electron microscopes and transmission electron microscopes. It is related to.

(b) Prior art For example, for devices such as scanning electron microscopes and transmission electron microscopes that require a high degree of evacuation of the chamber to be evacuated, gas molecules are mechanically removed by rotating a rotor. Turbomolecular pumps, which can be blown to obtain ultra-high vacuums, are sometimes used. However, the casing of a conventional turbomolecular pump has an inlet port at one end thereof, and has an integral structure in which a mounting flange is provided around the outer periphery of the inlet port. Therefore, when this mounting flange is connected to the chamber to be evacuated, there is a problem that minute vibrations of the turbo molecular pump are transmitted to the chamber to be evacuated. In other words, although the turbomolecular pump itself has very good dynamic balance as an ultra-high-speed rotating body, as it has mechanically moving parts, it is impossible to completely eliminate vibration. It is possible. Therefore, such minute vibrations are transmitted to the chamber to be evacuated via the mounting flange, resulting in a disadvantage that, in the case of the above-mentioned microscope, etc., the resolution is reduced.

Conventionally, in order to eliminate this inconvenience, a so-called bellows joint has been interposed between the mounting flange of the turbomolecular pump and the chamber to be exhausted, but this method requires a long piping length for the exhaust system. This causes a problem that piping resistance increases. Additionally, if this is the only type of device, the bellows joint would expand and contract every time the pressure at the intake port changes, so to prevent this, additional equipment is required to support the turbomolecular pump. There is the trouble of becoming.

(c) Purpose This invention was developed with attention to the above-mentioned circumstances, and since the mounting flange provided at the intake port can be directly connected to the chamber to be exhausted, etc., piping resistance increases. The purpose of the present invention is to provide a turbomolecular pump which does not have the inconvenience of necessitating special support facilities and is capable of effectively preventing vibrations from being transmitted to an evacuated chamber etc. even when directly connected. .

(d) Structure In order to achieve the above object, the present invention separates the casing end including the mounting flange from the casing main body, and interposes an elastic member between the casing end and the casing main body. The present invention is also characterized in that a sealing means is provided for airtightly connecting the intake port of the casing end to the intake port of the casing main body.

(E) Embodiment An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a schematic cross-sectional view of a turbomolecular pump according to the present invention. In the figure, 1 is a base plate, 2 is a motor erected on this base plate 1, and 3 is a motor supported by a rotating shaft 2a of this motor 2. A rotating rotor, 4 a stator, and 5 a casing.
The casing 5 has a cylindrical shape with a suction port 6 opened at one end and a mounting flange 7 provided on the outer periphery of the open end of the suction port 6, and is mounted on the base plate 1 via bolts 8. has been done. The casing 5 is separated into a casing end 9 including the mounting flange 7 and a casing main body 10, and an elastic member 12 is interposed between the casing end 9 and the casing main body 10. has been done. Further, an O-ring 13 serving as a sealing means is provided between the two so that the intake ports are connected airtightly. The casing end 9 is a short cylindrical body having the mounting flange 7 on the outer periphery of one end, and the other end is slidably fitted to the inner periphery of the upper end of the casing main body 10. The casing main body 10 is a cylindrical body surrounding the stator 4, and has a stepped portion 11 near its upper end for pressing and fixing the stator 4 to the base plate 1, and has the bolts on the outer periphery of its lower end. It has a flange 14 for locking the head of 8. An annular groove 15 is provided on the inner periphery of the upper end of the casing main body 10, and the O-ring 13 is housed in the annular groove 15 in close contact with the outer circumferential surface of the casing end 9. Further, the elastic member 12 is formed by bolts 12b and 12c protruding from both ends of a cylindrical vibration isolating rubber 12a.One bolt 12b is screwed into the mounting flange 7, and the other bolt A bolt 12c is screwed onto the upper end surface of the casing main body 10. Then, such elastic member 1
2 are provided at equal angular intervals in the circumferential direction. During operation, compressive force due to atmospheric pressure is applied to these elastic members 12 in a magnitude corresponding to the effective cross-sectional area of this turbomolecular pump, so the number and number of elastic members 12 are determined in consideration of the influence of such compressive force. The thickness, hardness, etc. are selected.

With this configuration, the casing end 9 is separated from the casing main body 10 and the two are connected by the elastic member 12, so that vibrations generated from the rotating part on the casing main body 10 side are transmitted to the casing main body 10. It is possible to effectively prevent this from being transmitted to the mounting flange 7 on the end portion 9 side. Therefore, even if the mounting flange 7 is directly connected to the chamber to be evacuated, there is no possibility that the chamber to be evacuated will be adversely affected by vibration. Moreover, unlike when using bellows fittings, the piping length does not become long, so
There is no inconvenience such as increased piping resistance or increased installation space, and the workability of installation is no different from that of directly connecting a conventional type to the chamber. Further, if the O-ring 13 is used as the sealing means as in this embodiment, it is cheaper than using a bellows joint.

Note that the elastic member is not limited to one made of rubber, and may be one using a metal spring, for example.

Further, the sealing means is not limited to the O-ring as in the above embodiment, but is also made of metal, for example, as shown in FIG. The bellows 16 or the like may be used.

(F) Effect Since the present invention has the above-mentioned configuration, by directly connecting the mounting flange provided at the intake port to the chamber to be exhausted, etc., piping resistance increases and special problems are avoided. It is possible to provide a turbo-molecular pump that can eliminate the inconvenience of requiring support equipment, and can also effectively prevent vibrations from being transmitted to a chamber to be evacuated or the like even when directly connected.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
FIG. 2 is a partial sectional view showing another embodiment of the present invention. 5...Casing, 6...Suction port, 7...Mounting flange, 9, 9'...Casing end, 10,
10'...Casing main body part, 12...Elastic member,
13... Sealing means (O ring), 16... Sealing means (bellows).

Claims (1)

[Scope of utility model registration request] In a turbomolecular pump in which an intake port is opened at one end of the casing and a mounting flange is provided on the outer periphery of the open end of the intake port, the casing end including the mounting flange is separated from the casing main body, and the casing end is separated from the casing main body. A turbo molecule characterized in that an elastic member is interposed between the end portion of the casing and the casing body, and a sealing means is provided for airtightly connecting the intake port of the casing end to the intake port of the casing body. pump.