JP2000240587A - Closed fluid device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the corrision of a magnetic bearing and a driving motor and to prevent the intrusion of impurity into the working fluid in a sealed chamber from the magnetic bearing and the driving motor, by preventing the leakage of the working fluid to the outside of the closed chamber even when the working fluid is a corrosive gas. SOLUTION: An impeller 11 for introducing and sending a working gas is rotatably mounted in a closed chamber 10, and a rotary shaft 12 projecting from this closed chamber 10 is rotatably supported by the magnetic bearings 14, 17 in a non-contact state. This rotary shaft 12 is rotated and driven by a driving motor 16 in a non-contact state, and the rotary shaft 12 projecting from the closed chamber 10 is surrounded by a closed shield thin wall 20 made of a non-magnetic body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic fluid device in which a rotary shaft for rotatingly driving an impeller disposed in a closed chamber is supported by a magnetic bearing in a non-contact manner. To prevent corrosion of the drive motor, etc., even when the working fluid is a corrosive gas, and to prevent impurities from entering the working fluid in the closed chamber from the drive motor, etc. The present invention relates to a hermetic-type fluid device that can be reliably prevented.

[0002]

2. Description of the Related Art In a pump, a compressor or a blower, an impeller in a closed chamber is driven to rotate by a drive motor to blow working gas in the closed chamber.

For example, in Japanese Utility Model Laid-Open No. 4-121494, as shown in FIG. 11, an impeller 2 is rotatably supported by a rotary shaft 3 in a closed chamber 1, and a motor chamber 4 has A drive motor 5 for rotating and driving the rotating shaft 3 is provided. The closed chamber 1 and the motor chamber 4 are integrally formed so as to form a space sealed from the outside. In the closed chamber 1 and the motor chamber 4, the rotating shaft 3
Are rotatably supported in a non-contact manner by the magnetic force of three magnetic bearings 6.

As described above, the closed chamber 1 and the motor chamber 4 form a space sealed from the outside, and the rotating shaft 3 is rotatably supported by the magnetic bearing 6 in a non-contact manner. It is possible to effectively prevent the working gas introduced into the inside from leaking from the closed chamber 1 or the motor chamber 4 to the outside, and, as in the case where a bearing using lubricating oil is used, the working gas is No pollution.

[0005]

However, in the pump and the like disclosed in Japanese Utility Model Laid-Open Publication No. 4-121494 (FIG. 11), when the working gas is a corrosive gas, the closed chamber 1 and the motor chamber 4 are separated. Since the closed space is formed, the corrosive gas in the closed chamber 1 flows into the motor chamber 4 and touches the mold resin material of the drive motor 5, and the mold resin material is corroded and deteriorated by the corrosive gas. In some cases, continuous operation for a long time is difficult.

Further, for example, as in a turbo molecular pump,
In some cases, it is necessary to avoid mixing impurities into the working gas introduced into the closed chamber 1 as much as possible. However, in the pump and the like disclosed in Japanese Utility Model Application Laid-Open No. 4-121494 (FIG. 11), since the closed chamber 1 and the motor chamber 4 form a closed space, the drive motor 5 and the magnetic bearing 6 are not molded. Impurities penetrate into the closed chamber 1 from the resin material,
There is a possibility that it may be mixed with the working gas in the inside, and it may be difficult to reliably prevent the mixing of this impurity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents the working fluid from leaking out of the closed chamber, so that even if the working fluid is a corrosive gas, the drive motor or the like may be used. It is an object of the present invention to provide a sealed fluid device that can effectively prevent corrosion of components and can surely prevent impurities from entering components into a working fluid in a closed chamber from components such as a drive motor. .

[0008]

In order to achieve the above-mentioned object, a sealed fluid device according to the present invention is provided with an impeller for introducing and delivering a working fluid in a closed chamber in a rotatable manner. A rotating shaft protruding from the sealed chamber is rotatably supported in a non-contact manner by a magnetic bearing, and the rotating shaft is rotatably driven in a non-contact manner by a drive motor. The rotating shaft is surrounded by a thin shielded thin wall made of a non-magnetic material.

As described above, according to the present invention, the rotating shaft projecting from the closed chamber is surrounded by the closed shield thin wall made of a non-magnetic material. That is, the closed shield thin wall forms a closed space having the impeller and the rotation shaft therein in cooperation with the closed chamber, and the magnetic bearing and the drive motor are arranged outside the closed space. . Therefore, the working fluid introduced into the closed chamber by the impeller can be sealed in the closed space, so that the working fluid does not leak from the closed space to the outside, and impurities and the like enter the closed space from the outside. No intrusion.

Therefore, even when the working fluid is a corrosive gas, corrosion of the magnetic bearing and the drive motor can be effectively prevented, and impurities can be reliably mixed into the working fluid from the magnetic bearing and the drive motor. Can be prevented.

On the other hand, the magnetic bearing and the drive motor are arranged outside the closed shield thin wall, but are configured to support or rotate the rotating shaft in a non-contact manner by magnetic force. Is made of a non-magnetic material, so that the magnetic bearings and the drive motors can favorably support or rotate the rotating shaft in a non-contact manner by a magnetic force without being magnetically affected by the sealed shield thin wall. be able to.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a closed type fluid device according to an embodiment of the present invention.

FIG. 1 is a sectional view of a sealed type fluid device according to a first embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a mounting portion of the sealed shield thin wall shown in FIG. FIG.
It is an expanded sectional view of the thrust magnetic bearing shown in FIG.

As shown in FIG. 1, in a fluid device such as a pump, a compressor, or a blower, a working gas is introduced into an enclosed chamber 10 from an inlet (not shown) and is sent out from an outlet (not shown). A plurality of impellers 11 are rotatably arranged, and a rotating shaft 12 for the impeller 11 is provided with a pair of touchdown bearings 1 in a wall of the closed chamber 10.
It is rotatably supported by 3 and 13. The touch-down bearing 13 has a touch-down gap in the radial direction smaller than a radial gap of a radial magnetic bearing 14 described later and a touch-down gap smaller than a radial gap of a thrust magnetic bearing 17 described later. ing.

The rotating shaft 12 protruding from the closed chamber 10
Are rotatably supported in a non-contact manner by a pair of radial magnetic bearings 14 on both sides thereof, and each radial magnetic bearing 14 has a stator portion 14b having a coil 14a.
And a rotor portion 14c on the rotating shaft 12 side.

The radial magnetic bearing 14 is provided on the rotating shaft 12.
And a controller (not shown) that detects the inductance of the sensor coil 15 that changes based on the change in the radial gap. The feedback control is performed to increase or decrease the current flowing through the coil 14a of the stator section 14b in response to the change in the radial direction, so that the radial gap is constantly maintained.

The rotating shaft 12 is driven to rotate by a driving motor 16.
Is composed of a stator section 16b having a coil 16a and a rotor section 16c on the rotating shaft 12 side.

Both ends of the rotating shaft 12 are rotatably supported in a non-contact manner by a pair of thrust magnetic bearings 17, 17, and each of the thrust magnetic bearings 17 has a stator portion having a coil 17a as shown in FIG. 17b and a rotor portion 17c at the end face of the rotating shaft 12. The rotor portion 17c has an annular space 17d.
, A ferromagnetic thrust magnetic pole is formed, and this thrust magnetic pole may be formed on the rotating shaft 12 itself, or may be embedded separately. Such a thrust magnetic bearing 17 is, as shown by an arrow in FIG.
A closed magnetic circuit is configured to support the end face of the rotating shaft 12 in a non-contact manner.

On the outer diameter side of the coil 17a, there is provided a sensor coil 18 for detecting an axial gap (d) between the end face of the rotating shaft 12 and the stator portion 17b. The controller (not shown) detects the inductance of the sensor coil 18 that changes based on the change in the gap (d), and performs feedback control to increase or decrease the current flowing through the coil 17a of the stator portion 17b in accordance with the change in the inductance. To maintain the gap (d) in the axial direction constant.

Further, in the present embodiment, as shown in FIG. 1, the rotating shaft 12 protruding from the sealed chamber 10 is surrounded by a sealed shield thin wall 20, and a radial magnetic bearing 14, a drive motor 16, The thrust magnetic bearing 17 is arranged outside the closed magnetic shield thin wall 20.

The base end portion 20a of the sealed shield thin wall 20
As shown in FIG. 2, a screw 22 is inserted through an O-ring 21.
And is hermetically attached to the vertical wall 10a of the closed chamber 10. Alternatively, the closed shield thin wall is attached to the upright wall 10a by welding as shown in FIG. Also,
The closed shield thin wall 20 is formed of a non-magnetic material such as stainless steel or brass.

As described above, the sealed shield thin wall 20 cooperates with the sealed chamber 10 to form a closed space having the impeller 11 and the rotating shaft 12 therein, and a magnetic bearing is provided outside the closed space. 14 and 17 and a drive motor 16 are arranged. Therefore, the working gas introduced into the closed chamber 10 by the impeller 11 can be sealed in the closed space, does not leak out from the closed space, and impurities and the like are closed from the outside. It does not enter the space. Therefore, even when the working gas is a corrosive gas, the corrosion of the molding resin material of the magnetic bearings 14, 17 and the drive motor 16 can be effectively prevented, and the operation from the magnetic bearings 14, 17 and the drive motor 16 can be prevented. It is possible to reliably prevent impurities from being mixed into the gas.

At this time, the radial magnetic bearing 14, the drive motor 16 and the thrust magnetic bearing 17 are arranged outside the closed shield thin wall 20, as described above, but the rotating shaft 12 is not moved by the magnetic force. It is configured to be supported or rotated by contact, and the closed shield thin wall 20
Are made of a non-magnetic material such as stainless steel as described above, so that the magnetic bearings 14, 17 and the drive motor 16
Can freely rotate the rotating shaft 12 in a non-contact manner by a magnetic force without being magnetically affected by the sealed shield thin wall 20 and can rotate the rotating shaft 12 in a non-contact manner by a magnetic force. Can be driven.

Next, FIG. 5 is a sectional view of a sealed fluid device according to a second embodiment of the present invention, and FIG. 6 is an enlarged sectional view of the magnetic coupling shown in FIG.

In the second embodiment, as shown in FIG. 5, the rotating shaft 12 protruding from the closed chamber 10 is rotatably supported on both sides by a pair of radial magnetic bearings 14 in a non-contact manner. The left end of the rotating shaft 12 is rotatably supported in a non-contact manner by a single thrust magnetic bearing 17, while the right end of the rotating shaft 12 has a magnetic coupling 30.
Is connected to the drive motor 16 via the.

In this magnetic coupling 30, as shown in FIG. 6, a coupling housing 31 is connected to the drive shaft 16d of the drive motor 16, and
A back yoke 32 is disposed radially inward of 1, and a pair of permanent magnets 33, 33 are attached to the inner diameter side of the back yoke 32. On the other hand, a back yoke 34 is also provided on the rotating shaft 12 side, and a pair of permanent magnets 35 are attached to the outer diameter side of the back yoke 34. Thereby, the permanent magnet 33 → the permanent magnet 35 →
A magnetic circuit through which a magnetic flux passes in the order of back yoke 34 → permanent magnet 35 → permanent magnet 33 → back yoke 32 → permanent magnet 33 is configured.
The rotation force of the drive shaft 16d is transmitted to the rotation shaft 12 by magnetic force, and serves to rotate the rotation shaft 12 in a non-contact manner.

Further, a permanent magnet 36 is provided on the inner side in the axial direction of the housing 31, and a permanent magnet 37 is mounted on the rotating shaft side so as to face the permanent magnet 36. Thereby, the magnetic coupling 30 also functions as a thrust magnetic bearing.

Next, FIG. 7 is a sectional view of a sealed fluid device according to a third embodiment of the present invention.

The third embodiment is different from the second embodiment in that a radial magnetic coupling 40 is used instead of the magnetic coupling 30.

This radial type magnetic coupling 40 is
The configuration is the same as that of the magnetic coupling 30 shown in FIG. 6 except that the permanent magnets 36 and 37 in the axial direction are not provided. That is, the radial type magnetic coupling 40 is the same as the radial permanent magnet 3 of the magnetic coupling 30 shown in FIG.
3, 35 and back yokes 32, 34,
The rotating force of the drive shaft 16d of the drive motor 16 is transmitted to the rotating shaft 12 by magnetic force, and serves to rotate the rotating shaft 12 in a non-contact manner. Although the radial type magnetic coupling 40 does not have the permanent magnets 36 and 37 in the axial direction,
It exerts the axial restoring force and also acts as a thrust bearing.

Next, FIG. 8 is a sectional view of a sealed type fluid device according to a fourth embodiment of the present invention, and FIG. 9 (a) is an enlarged sectional view of the axial type magnetic coupling shown in FIG. It is a figure and FIG.9 (b) is an arrow view along the bb line of FIG.9 (a).

The fourth embodiment differs from the second and third embodiments in that an axial magnetic coupling 50 is used instead of the magnetic coupling 30 and the radial magnetic coupling 40. is there.

This axial type magnetic coupling 50
As shown in FIGS. 9A and 9B, a coupling housing 51 is connected to a driving shaft 16d of a driving motor, and a pair of permanent magnets 5
2 are provided, a plurality of pairs of permanent magnets 52 are provided at equal intervals in the circumferential direction, and on the back of each pair of permanent magnets 52,
A back yoke 53 is provided. On the other hand, a pair of permanent magnets 54 are also provided on the end face of the rotating shaft 12, and FIG.
As shown in (b), a plurality of pairs of permanent magnets 54 are arranged at equal intervals in the circumferential direction, and a back yoke 55 is provided on the back surface of each pair of permanent magnets 54. Thereby, one permanent magnet 52 → the back yoke 53 → the other permanent magnet 5
2 → one permanent magnet 54 → back yoke 55 → the other permanent magnet 54 → a permanent magnet 52 constitutes a magnetic circuit through which magnetic flux passes in this order, and an axial type magnetic coupling 50
Functions to transmit the rotational force of the drive shaft 16d of the drive motor 16 to the rotary shaft 12 by magnetic force, and to rotate the rotary shaft 12 in a non-contact manner.

The axial type magnetic coupling 50
Is configured to rotate the rotating shaft 12 by applying a magnetic attraction force to the end face of the rotating shaft 12, so that the rotating shaft 12 may be drawn toward the coupling 50 by the attraction force. At the other end, a thrust magnetic bearing 17 is provided to balance the attraction force of the two, thereby preventing the rotating shaft 12 from being pulled.

FIG. 10 is a sectional view of a sealed fluid device according to a fifth embodiment of the present invention.

The fifth embodiment differs from the first to fourth embodiments in that a radial magnetic bearing motor 60 is used instead of the radial magnetic bearing 14 and the drive motor 16.

The radial magnetic bearing motor 60 includes a stator 60b having an electromagnetic pole coil 60a and a rotating shaft 1
It has a function of a radial magnetic bearing and a function of a drive motor, and is superimposed on a position control current for non-contact floating of the rotating shaft 12 to rotate. The driving current is supplied to the electromagnetic pole coil 60a.
To achieve non-contact floating and rotational movement. In addition, it also has a sensor coil 61 for detecting a radial gap with the rotating shaft 12.

The present invention is not limited to the above-described embodiment, but can be variously modified.

[0039]

As described above, according to the present invention,
The rotation shaft protruding from the closed chamber is surrounded by a closed shield thin wall made of a non-magnetic material. That is, the closed shield thin wall forms a closed space having the impeller and the rotation shaft therein in cooperation with the closed chamber, and the magnetic bearing and the drive motor are arranged outside the closed space. . Therefore, the working fluid introduced into the closed chamber by the impeller can be sealed in the closed space, so that the working fluid does not leak from the closed space to the outside, and impurities and the like enter the closed space from the outside. No intrusion.

Therefore, even when the working fluid is a corrosive gas, corrosion of the magnetic bearing and the drive motor can be effectively prevented, and impurities can be reliably mixed into the working fluid from the magnetic bearing and the drive motor. Can be prevented.

On the other hand, the magnetic bearing and the drive motor are arranged outside the closed shield thin wall, but are configured to support or rotate the rotating shaft in a non-contact manner by magnetic force. Is made of a non-magnetic material, so that the magnetic bearings and the drive motor can be freely supported or freely rotatably contactlessly by magnetic force without being magnetically affected by the sealed shield thin wall. It can be driven to rotate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sealed fluid device according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a mounting portion of the closed shield thin wall shown in FIG.

FIG. 3 is an enlarged cross-sectional view of a modified example of the mounting portion of the sealed shield thin wall shown in FIG.

FIG. 4 is an enlarged sectional view of the thrust magnetic bearing shown in FIG.

FIG. 5 is a sectional view of a sealed fluid device according to a second embodiment of the present invention.

FIG. 6 is an enlarged sectional view of the magnetic coupling shown in FIG. 5;

FIG. 7 is a sectional view of a sealed fluid device according to a third embodiment of the present invention.

FIG. 8 is a sectional view of a sealed fluid device according to a fourth embodiment of the present invention.

9A is an enlarged cross-sectional view of the axial magnetic coupling shown in FIG. 8, and FIG. 9B is a cross-sectional view of FIG.
The arrow view along the b line.

FIG. 10 is a sectional view of a sealed fluid device according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view of a conventional sealed fluid device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Closed room 10a Standing wall of closed room 11 Impeller 12 Rotary shaft 13 Touchdown bearing 14 Radial magnetic bearing 14a Coil of radial magnetic bearing 14b Stator portion of radial magnetic bearing 14c Rotor portion of radial magnetic bearing 15 Sensor coil 16 Drive motor 16a Drive Motor Coil 16b Drive Motor Stator 16c Drive Motor Rotor 16d Drive Shaft 17 Thrust Magnetic Bearing 17a Thrust Magnetic Bearing Coil 17b Thrust Magnetic Bearing Stator 17c Thrust Magnetic Bearing Rotor 18 Sensor Coil 20 Sealed Shield Thin Wall Reference Signs List 20a Base end 21 O-ring 22 Screw 30 Magnetic coupling 31 Coupling housing 32 Housing-side back yoke 33 Housing-side permanent magnet 34 Rotation axis-side back yoke 35 times Shaft side permanent magnet 36 Housing side permanent magnet 37 Rotation axis side permanent magnet 40 Radial type magnetic coupling 50 Axial type magnetic coupling 51 Coupling housing 52 Housing side permanent magnet 53 Housing side back yoke 54 Rotation axis side Permanent magnet 55 Back yoke on rotating shaft side 60 Radial magnetic bearing motor 60a Electromagnetic pole coil of radial magnetic bearing motor 60b Stator part of radial magnetic bearing motor 60c Rotor part of radial magnetic bearing motor 61 Sensor coil

Claims (1)

[Claims] An impeller for introducing and blowing a working fluid is rotatably disposed in a sealed chamber, and a rotating shaft protruding from the sealed chamber is rotatably supported in a non-contact manner by a magnetic bearing. In a sealed fluid device in which the rotating shaft is driven to rotate in a non-contact manner by a drive motor, the rotating shaft protruding from the sealed chamber is surrounded by a sealed shield thin wall made of a non-magnetic material. Closed fluid device.