JPH0626521A - Magnetic bearing device - Google Patents

Abstract

PURPOSE:To provide a magnetic bearing device which can be controlled even if a part of an insulated electric wire of a bearing coil is broken so that a rotary unit is not damaged. CONSTITUTION:A magnetic bearing device is provided with a rotor yoke made of a magnetic material, fixed to a rotary shaft, an electromagnetic stator secured to a casing with a slight clearance between the rotor yoke and the same, and a deviation sensor for measuring a deviation quantity of the rotary shaft. Magnetic force applying between the rotor yoke and the electromagnetic stator is controlled on the basis of a signal output from the deviation sensor so that the rotary shaft can be supported in magnetic non-contact. Bearing coils 15b, 16b are such constituted that a plurality of copper wires 41 electrically connected at both ends 100, 200 are wound around electromagnetic stators 15c, 16c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device for supporting a rotary shaft in a non-contact state, and more particularly to improvement of a bearing coil of an electromagnet.

[0002]

2. Description of the Related Art A magnetic bearing device supports a rotating shaft of a turbo machine, a machine tool or the like in a non-contact manner by magnetic force. Since this device has no mechanical frictional part, it has small energy loss, no temperature is generated, and no lubricating oil is required. Therefore, maintenance is easy. Therefore, in recent years, it has been increasingly put into practical use with the progress of power electronics technology.

In such a magnetic bearing device, a rotary shaft having a rotor yoke is arranged at a central position, and a plurality of electromagnets around which a bearing coil 1 is wound are provided around the rotary shaft, as shown in FIG. By arranging the stators 2 evenly and controlling each of the electromagnet stators 2 to attract the rotor yoke, the rotary shaft is rotatably supported in the radial direction without contact. On the other hand, in the thrust direction, as shown in FIG. 5, a pair of electromagnet stators 4 around which the bearing coil 3 is wound are arranged so as to face each other, and a rotor of a rotary shaft is interposed between the pair of electromagnet stators 4. Then, the electromagnet stators 4 attract the rotor, thereby supporting the rotor in the thrust direction in a non-contact manner.

[0004]

However, the electromagnet stators 2 and 4 in the conventional magnetic bearing device are wound with the single copper wire 5 having the insulating coating to form the bearing coils 1 and 3. The bearing coils 1 and 3 generate a magnetomotive force that attracts the rotor yoke of the rotating shaft and the rotor.

In this case, if the copper wire 5 of one of the bearing coils 1 and 3 breaks for some reason, the magnetic force of the bearing coils 1 and 3 becomes zero and normal control of this magnetic bearing device is impossible. Becomes For example, even if the copper wire 5 is a thick wire, it is appropriate to consider that the breakage of the copper wire 5 will rapidly progress if a crack or the like occurs in a part of the copper wire 5. .

In such a case, the control of the magnetic bearing device becomes impossible, so that the rotating shaft such as the rotating shaft and the rotating portion such as the rotor yoke come into contact with the stationary electromagnet stators 2 and 4. Therefore, there is a problem that the contacted portion is greatly damaged.

The present invention has been made in order to solve the above problems, and it is possible to control the magnetic bearing device even if a part of the insulated wire of the bearing coil is broken, and the rotating part is not damaged. An object is to provide a bearing device.

[0008]

In a magnetic bearing device according to the present invention, a rotor yoke made of a magnetic material attached to a rotary shaft and a bearing coil for generating a magnetomotive force are wound around the rotor yoke. An electromagnet stator attached to the casing with a minute gap therebetween and a displacement sensor for measuring the displacement amount of the rotary shaft are provided, and the rotor yoke and the rotor yoke are provided on the basis of an output signal from the displacement sensor. A magnetic bearing device for controlling the magnetic force acting between an electromagnet stator and magnetically supporting the rotating shaft in a non-contact manner, wherein the bearing coils are connected in parallel at both ends. A plurality of insulated wires are wound around the electromagnet stator.

Further, it is preferable to provide a monitoring device for monitoring the impedance of the bearing coil.

[0010]

In the present invention, both ends of a plurality of insulated wires are electrically joined to form a bundle of parallel wires, and the bundled insulated wires are wound around an electromagnet stator to form a bearing coil. Even if, for example, one of the bundled copper wires is broken, the remaining insulated wire can continue to flow current, and the bearing coil will continue to generate magnetic force. In this case, since the impedance of the bearing coil changes, it is possible to detect the state of breakage of the insulated wire by monitoring the presence or absence of this change with a monitoring device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the overall structure of the magnetic bearing device according to this embodiment. As shown, the magnetic bearing device 1
Reference numeral 0 has a cylindrical casing 11, and a rod-shaped rotating shaft 12 is rotatably arranged in one direction or in the forward and reverse directions at the center position in the vertical direction inside the casing. This rotating shaft 12
The rotor 14 of the motor 13 is fixed to the motor 1.
The rotary shaft 12 is rotationally driven by 3. The rotary shaft 12 is
The two radial magnetic bearings 15 and 16 magnetically support the radial direction (radial direction) in a non-contact manner, and the thrust magnetic bearing 17 magnetically supports the thrust direction (axial direction) in a non-contact manner. ing. The magnetic forces of the radial magnetic bearings 15 and 16 are controlled based on the outputs of radial displacement sensors 18 and 19 as displacement sensors that measure the relative displacement between the rotor 12 and the casing 11 in the radial direction. There is. Also, thrust magnetic bearing 1
The magnetic force of 7 is controlled based on the output of a thrust displacement sensor 20 as a displacement sensor that measures the relative displacement in the thrust direction between the rotor 12 and the casing 11.

The radial magnetic bearings 15 and 16 are wound around rotor yokes 15a and 16a, which are attached to the rotary shaft 12 and are formed by laminating silicon steel plates which are magnetic materials, and bearing coils 15b and 16b which generate magnetomotive force. And the electromagnet stators 15c and 16c attached to the casing 11 with a minute gap between the rotor yokes 15a and 16a. A plurality of the electromagnet stators 15c and 16c are evenly arranged in the circumferential direction on the inner peripheral surface 31 of the casing 11. For example, as shown in FIG. Protrusions 34, which are evenly arranged in the circumferential direction on 33, are projected in the center direction, and the bearing coils 15b and 16b are wound around the protrusions 34.

The thrust magnetic bearing 17 is formed by winding a rotor yoke 17a made of a magnetic material attached to the rotary shaft 12 and a bearing coil 17b for generating a magnetomotive force as shown in FIGS. It has an electromagnet stator 17c attached to the casing 11 with a minute gap between it and the yoke 17a. Each electromagnet stator 17c is attached to the casing 11 so that the surface 17d of the electromagnet stator 17c on which the bearing coil 17b is wound faces the rotor yoke 17a.

The radial displacement sensors 18 and 19 are located near the radial magnetic bearings 15 and 16, respectively, and are fixed to the casing 11. The sensor cores 18a and 19a are fixed to the casing 11.
And sensor coils 18b and 19b in which insulated wires are wound around the sensor cores 18a and 19a, respectively, and the surfaces of annular sensor targets 18c and 19c attached to the rotary shaft 12 are measured. As a result, the displacement amount of the rotary shaft 12 in the radial direction is detected, and the detection result is output.

The thrust displacement sensor 20 includes the casing 1
Sensor core 20a attached to the lid member 11a of No. 1
And a sensor coil 20b in which an insulated wire is wound around the sensor core 20a, and the surface of a sensor target 20c attached to one axial end 12a of the rotary shaft 12 is measured. Thus, the amount of displacement of the rotary shaft 12 in the thrust direction is detected, and the detection result is output.

Each bearing coil 15b, 16b, 17b
2 and 3, as shown in FIGS.
A plurality of parallel connections (three in this embodiment) electrically connected by
The flexible insulated wire 41 of the electromagnet stator 15c,
16c and 17c, respectively. As the insulated wire 41 of this embodiment, a copper wire 41 having an insulating coating is used, but in addition, for example, an aluminum wire, etc.
A wire made of a metal having excellent conductivity or an alloy thereof may be used.

Each bearing coil 15b, 16b, 17
As for b, a coil manufactured by separately winding may be attached to the electromagnet stator and may be grouped at the inlet end 100 and the outlet end 200 respectively, but a coil in which a plurality of copper wires 41 are wound at the same time is used. Using the inlet end 100 and the outlet end 20
You may collect 0 respectively. As described above, in the present embodiment, the copper wire 41 wound around the bearing coil can be divided into thin wires and wound, so that the winding operation becomes easy.

Furthermore, in the apparatus of this embodiment, for example, one of the copper wires 41 of the bearing coils 15b, 16b, 17b in which the three copper wires 41 joined in parallel are wound in parallel is broken. In this case, in order to quickly detect this abnormality, a monitoring device for monitoring the impedance of each bearing coil 15b, 16b, 17b is provided. Thus, the presence or absence of breakage of the copper wire 41 is judged from the change in impedance of the bearing coils 15b, 16b, 17b, and if there is an abnormality, the magnetic bearing device is stopped and the target bearing coil is replaced when control is possible. Can be done promptly. Since each bearing coil is formed by winding a plurality of conductive wires in parallel, the abnormality can be easily determined. Therefore, the operation of the magnetic bearing device can be promptly repaired without trouble such as touch and the system can be resumed normally.

In the magnetic bearing device configured as described above, the detection signals output from the radial displacement sensors 18 and 19 and the thrust displacement sensor 20 for measuring the displacement of the rotary shaft 12 are the magnetic bearings 15 and 16, respectively. It is processed by each sensor amplifier for 17. The output signal from each of the sensor amplifiers is sent to a compensator, which composes the rotary shaft 12 based on the input signal and a predetermined target value.
A control signal for controlling the amount of displacement of the power amplifier is output to the power amplifier.
This power amplifier uses the control signals that have been input to each bearing coil 15 of each magnetic bearing 15, 16 and 17.
Excite b, 16b, and 17b. Excited bearing coils 15b, 16b, 17b and electromagnet stators 15c, 1
6c and 17c are rotor yokes 15a, 16a and 17c.
A magnetic attraction force for attracting a is generated to support the rotating shaft 12 at the central position of the casing 11 in a non-contact state. As a result, the rotating shaft 12 is rotationally driven by the motor 13 while being supported by the magnetic force in a non-contact state. In the drawings, the same reference numerals indicate the same or corresponding parts.

[0020]

Since the present invention is configured as described above, even if a part of the insulated wire of the bearing coil is broken, another insulated wire connected in parallel with the broken wire continues to flow current, so that the bearing coil Does not become zero, the bearing device can be controlled, and the rotating part is not damaged.

[Brief description of drawings]

1 is a diagram showing an embodiment of the present invention, FIG.
FIG. 1 is a sectional view showing the overall structure of the magnetic bearing device according to this embodiment.

FIG. 2 is a partially cutaway perspective view showing a structure of an electromagnet of a radial magnetic bearing mounted on the magnetic bearing device.

FIG. 3 is a partially cutaway perspective view showing a structure of an electromagnet of a thrust magnetic bearing mounted on the magnetic bearing device.

4 and 5 are views showing a conventional technique, and FIG. 4 is a partially cutaway perspective view showing a structure of an electromagnet of a conventional radial magnetic bearing.

FIG. 5 is a partially cutaway perspective view showing a structure of an electromagnet of a conventional thrust magnetic bearing.

[Explanation of symbols]

 10 Magnetic Bearing Device 11 Casing 12 Rotating Shafts 15a, 16a, 17a Rotor Yoke 15b, 16b, 17b Bearing Coil 15c, 16c, 17c Electromagnet Stator 18, 19 Radial Displacement Sensor (Displacement Sensor) 20 Thrust Displacement Sensor (Displacement Sensor) 41 Copper wire (insulated wire) 100,200 Both ends of bearing coil

Claims (2)

[Claims] 1. A rotor yoke made of a magnetic material attached to a rotary shaft and a bearing coil for generating a magnetomotive force are wound, and the rotor yoke is attached to a casing with a minute gap between the rotor yoke and the rotor yoke. An electromagnet stator and a displacement sensor that measures the amount of displacement of the rotating shaft are provided, and the magnetic force acting between the rotor yoke and the electromagnet stator is controlled based on the output signal from the displacement sensor. A magnetic bearing device for magnetically supporting the rotating shaft in a non-contact manner, wherein the bearing coil is configured by winding a plurality of parallel insulated wires electrically joined at both ends around the electromagnet stator. A magnetic bearing device characterized by being configured. 2. The magnetic bearing device according to claim 1, further comprising a monitoring device for monitoring impedance of the bearing coil.