JP3095487B2 - Magnetic bearing device - Google Patents

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 applied to a floating object, for example, a high-speed rotating body such as a turbo-molecular pump, a compressor, a turbine, and a spindle for a machine tool.

[0002]

2. Description of the Related Art As means for floatingly holding a high-speed rotating body,
There is a magnetic bearing using an electromagnet. Referring to FIG. 5, the conventional example is described. Reference numeral 4 is a rotating body, 5a and 5b are a pair of magnetic bearings (journal bearings) rotatably supporting the rotating body 4, and 6a and 6b are floating positions of the rotating body 4. It is a position sensor to detect.

The floating position of the rotating body 4 is determined by position sensors 6a and 6
b, and based on a detection signal obtained at that time, a value of a current flowing through electromagnets (not shown) provided in the magnetic bearings 5a and 5b is determined, and a magnitude of a magnetic force generated in the electromagnets is controlled. The floating position of the body 4 is set.
FIG. 6 is a block diagram of the magnetic bearing control device. In FIG. 6, 1 is a magnetic bearing control device, 2 is a structure having a rotating body (for example, a casing), 3 is a portion for restricting compatibility, 7 is a position sensor, and 8 is a center position (offset).
An adjuster, 9 is a position feedback gain adjuster, 10 is a filter, 11 is a control circuit, and 12 is an electromagnet.

[0004] The center position (offset) adjuster 8 comprises:
The mechanical displacement of the floating holding center of the rotating body due to an assembly error when the position sensor 7 is installed is electrically corrected and adjusted. This adjustment value differs for each device having a magnetic bearing. The position feedback gain adjuster 9 converts the output voltage value of the position sensor 7 into a displacement amount from the floating center of the rotating body 4 and includes a function of correcting different sensitivities of the position sensor 7 for each point. I have.

[0005] The filter 10 has a high frequency hunting (natural vibration mode of a rotating body bending mode) which is generated with a low attenuation capability due to a high gain and a phase delay in a high frequency region of a magnetic bearing.
The center frequency of the filter 10 is set differently for each device having a magnetic bearing in order to match the center frequency of the rotating body 4 in order to ensure rotational stability.

The control circuit 11 generally controls the position of the rotator 4 with respect to the deviation amount from the floating center, and ensures a gain and a phase designed to attenuate the oscillation of the rigid mode eigenvalue of the rotator 4. It is composed of a proportional element, an integral element, and a differential element (PID element). Normally, the center position (offset) adjuster 8, the position feedback gain adjuster 9, the filter 10, and the control circuit 11 are incorporated in the magnetic bearing control device 1, and the position sensor 7 and the electromagnet 12 control the rotating body. Embedded in the structure 2 having

[0007]

[Problems to be solved by the invention]

(1) In general, an apparatus having a magnetic bearing includes a structure having a rotating body and a magnetic bearing control device for controlling the floating of the rotating body.
Consists of two units. Of course, the magnetic bearing control device also includes an inverter for rotating the rotating body at high speed. The two units are connected by a magnetic bearing control cable and a motor drive cable. (2) The magnetic bearing control device has a portion that is adjusted or set according to the individuality of a structure having a rotating body. For example, a center position (offset) adjuster 8 for correcting a mechanical shift of the floating center of the rotating body due to an assembly error when the position sensor 7 is installed, and an output voltage value of the position sensor 7 is converted into a deviation amount from the floating center of the rotating body. The position feedback gain adjuster 9 for conversion and the filter 10 for attenuating the oscillation of the bending first-order eigenvalue of the rotating body correspond to this.

These adjustment values and set values differ for each structure having a rotating body, and the structure having a magnetic bearing control device and a rotating body is a one-to-one combination. (3) The magnetic bearing control device and the structure having the rotating body are:
Since the combination is one-to-one, if the combination is changed, the magnetic bearing control loses its normal function, and stable rotation cannot be guaranteed. (4) The inability to change this one-to-one combination, that is, the incompatibility between the magnetic bearing control device and the structure having the rotating body, significantly reduces the mass productivity of devices having the magnetic bearing. In addition, it is not preferable for management in after-sales service and handling of troubles.

The present invention has been made in view of the above problems, and has as its object to improve mass productivity in manufacturing an apparatus having a magnetic bearing. Further, when a magnetic bearing control device or a structure having a rotating body has a failure, it is sufficient to replace or repair the failed one, and to provide a magnetic bearing device capable of simplifying after-service of a device having a magnetic bearing. It is in.

[0010]

To achieve the above object of the Invention The present invention includes a position sensor for detecting a floating position of the floating holding object, and a magnetic bearing for holding the floating object by magnetic force After the structure , the center position adjustment and the position feedback gain adjustment are performed, and after passing through a filter tuned to the natural frequency of the floating object ,
Feedback the detection signal from the position sensor ,
In a magnetic bearing device having a magnetic bearing control device for controlling the magnetic force, a magnetic bearing device is provided between the magnetic bearing control device and a structure.
The part that limits the compatibility of the magnetic bearing is installed outside the magnetic bearing control device.

[0011]

According to the magnetic bearing device of the present invention, the magnetic
A part that restricts compatibility between the bearing control device and the structure is installed outside the magnetic bearing control device, and restricts the compatibility between the magnetic bearing control device and the structure having the rotating body. The factors are eliminated, and a structure (for example, a casing) having the magnetic bearing device and the rotating body is separately manufactured, so that mass productivity in manufacturing an apparatus having the magnetic bearing is improved. Further, when the magnetic bearing control device or the structure having the rotating body is out of order, replacement or repair of the failed one is sufficient, and the after-sales service of the equipment having the magnetic bearing is simplified.

[0012]

【Example】

(First Embodiment) Next, a magnetic bearing device according to the present invention will be described with reference to a first embodiment shown in FIGS. 1 is a magnetic bearing control device, 2 is a structure (for example, a casing) having a rotating body, 3 is a portion that limits compatibility, 7 is a position sensor,
8 is a center position (offset) adjuster, 9 is a position feedback gain adjuster, 10 is a filter, 11 is a control circuit, 12 is an electromagnet, and FIG. FIG. 2 shows a block diagram when the structure is incorporated into a structure (for example, a casing) 2 having a rotating body.

FIG. 2 shows an example in which the magnetic bearing device is applied to a turbo molecular pump. The output of the position sensor 7 is used as a center position (offset) adjuster (a center position adjuster for correcting the axial center position deviation of the rotating body 4 due to the installation of the position sensor 7) 8 and the output value of the position sensor 7 itself varies. Is adjusted by a feedback gain adjuster 9 that corrects the frequency, and after passing through a filter 10 tuned to the natural frequency of the rotating body 4, the magnetic force of an electromagnet 12 is controlled by a control circuit 11 using PID and phase compensation. Then, the rotating body 4 is levitated and held by the same magnetic force.

According to the characteristics of the turbo molecular pump body,
Adjusted or adjusted compatibility limiting part 3, ie
The center position (offset) adjuster 8, feedback gain adjuster 9, and filter 10 are integrated into a single unit and incorporated in the turbo molecular pump body. (Second Embodiment) Next, a magnetic bearing device according to the present invention will be described with reference to a first embodiment shown in FIGS. 3 is a magnetic bearing control device, 2 is a structure (for example, a casing) having a rotating body, 3 is a part that limits compatibility, 7 is a position sensor,
8 is a center position (offset) adjuster, 9 is a position feedback gain adjuster, 10 is a filter, 11 is a control circuit, and 12 is an electromagnet. FIG. FIG. 2 is a block diagram showing a case where the unit is separated from the magnetic bearing control device 1 and installed outside a structure (for example, a casing) 2 having a rotating body as one unit.

FIG. 4 shows an application example in which the magnetic bearing device is applied to a turbo molecular pump. The operation is the same as that of the turbo molecular pump shown in FIG.

[0016]

As described above, the magnetic bearing device of the present invention has a structure in which some of the control elements in the magnetic bearing control device are installed outside the magnetic bearing control device, and has a magnetic bearing control device and a rotating body. This eliminates the factor that limits compatibility with the magnetic bearing device and the structure (e.g., casing) having the magnetic bearing device and the rotating body can be separately manufactured, and is used when manufacturing equipment having the magnetic bearing. Mass productivity can be improved.

In addition, when the magnetic bearing control device or the structure having the rotating body is out of order, it is sufficient to replace or repair the failed one, and the after-service of the equipment having the magnetic bearing can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a magnetic bearing device according to the present invention.

FIG. 2 is a longitudinal sectional side view in which the magnetic bearing device is applied to a turbo-molecular pump.

FIG. 3 is a block diagram showing a second embodiment of the magnetic bearing device of the present invention.

FIG. 4 is a longitudinal sectional side view in which the magnetic bearing device is applied to a turbo molecular pump.

FIG. 5 is a side view showing a conventional magnetic bearing device.

FIG. 6 is a block diagram of the magnetic bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic bearing control apparatus 2 Structure (for example, casing) which has a rotating body 3 Part which limits compatibility 4 Rotating body 7 Position sensor 8 Center position (offset) adjuster 9 Position feedback gain adjuster 10 Filter 11 Control circuit 12 Electromagnet

Claims (1)

(57) [Claims] A position for detecting a floating position of a floating holding object.
Position sensorWhen,Magnetism that holds the object by magnetic force
bearingWhenStructure havingWhen,  Performs center position adjustment and position feedback gain adjustment
Tuned to the natural frequency of the floating object
After passing through the filterDetection signal from the position sensor
Number,feedbackTo control the magnetic forceMagnetic bearing
In a magnetic bearing device provided with a control device,The magnetic axis
Parts that limit compatibility between the receiving control device and the structureThe
Magnetic shaft characterized by being installed outside the magnetic bearing control device
Receiving device.