JPH09100835A - Magnetic bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the performance by reducing the eddy current and the hysteresis loss of a magnetic bearing of motor integration type. SOLUTION: A magnetic bearing device is provided with a pair of axial magnetic bearings 2 and two pairs of radial magnetic bearings 3, 4 to support a rotary shaft 1 in a non-contact manner. Two pairs of radial magnetic bearings 3, 4 are the magnetic bearing of motor integration type in which an attraction coil 13 to attract the rotary shaft 1 and a motor coil 12 to rotate the rotary shaft 1 are coiled around a common stator magnetic pole 11. The rotary shaft 1 is made of soft magnetic stainless steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a magnetic bearing device,
More specifically, the present invention relates to a magnetic bearing device in which at least one set of a plurality of magnetic bearing devices is a motor-integrated magnetic bearing.

[0002]

2. Description of the Related Art As a magnetic bearing device of this type, for example, Japanese Patent Application Laid-Open No. 3-32333.
The one described in Japanese Patent Publication No. 8 is known. This device has one set of axial magnetic bearings and two sets of radial magnetic bearings, and the two sets of radial magnetic bearings are motor-integrated magnetic bearings. The motor integrated magnetic bearing
The suction coil and the motor coil are wound on a common stator magnetic pole. By supplying a direct current to the suction coil, the rotary shaft is sucked and supported in a non-contact manner in the radial direction, and a three-phase AC current is applied to the motor coil. Is generated to generate a rotating magnetic field to drive the rotating shaft to rotate. Further, structural steel having a relatively low resistivity is used for the rotating shaft.

In the motor-integrated magnetic bearing as described above,
The rotating shaft is also used as a magnetic circuit, but since this rotating shaft is made of structural steel having a relatively low resistivity, there is a problem that eddy current and hysteresis loss are large and performance is significantly reduced.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a magnetic bearing device capable of improving the performance by reducing the eddy current and the hysteresis loss of the motor-integrated magnetic bearing.

[0005]

The magnetic bearing device according to the present invention comprises a plurality of sets of magnetic bearings for supporting the rotary shaft in a non-contact manner, and the at least one set of magnetic bearings attracts the rotary shaft. In the magnetic bearing device, which is a motor-integrated magnetic bearing in which a suction coil and a motor coil for rotationally driving the rotary shaft are wound on a common stator magnetic pole, the rotary shaft is made of soft magnetic stainless steel. It is a feature.

The resistivity of the soft magnetic stainless steel forming the rotating shaft is higher than that of the structural steel which is the material of the conventional rotating shaft. The resistivity of structural steel is 10 μΩ · cm, whereas that of soft magnetic stainless steel is 100 μΩ · cm. Therefore, the eddy current and the hysteresis loss of the motor-integrated bearing are smaller than those of the conventional magnetic bearing device, and the performance is significantly improved.

[0007]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows an example of the structure of a magnetic bearing device for supporting the rotating shaft (1) in a non-contact manner.

The axis (1) has, for example, a resistivity of 100 μΩ · c.
It is composed of soft magnetic stainless steel which is m. The magnetic bearing device comprises a set of axial magnetic bearings (2) and two sets of radial magnetic bearings (3) (4). These magnetic bearings
(2), (3) and (4) have the same structure as that of the magnetic bearing device described in the above-mentioned Japanese Patent Laid-Open No. 3-32338, for example. The axial magnetic bearing (2) includes a pair of electromagnets (5) (6) arranged so as to sandwich the flange portion (1a) formed on the shaft (1) from both sides in the axial direction. Electromagnet (5)
(6) is fixedly provided in the casing (7) of the magnetic bearing device, and the suction coil (8) is wound around it. Although not shown, the shaft (1) should be attached to the casing (7) at an appropriate position.
Is provided with an axial position sensor for detecting the position in the axial direction. And two electromagnets (5)
By supplying DC current to the coil (8) of (6), each electromagnet (5) (6) attracts the shaft (1) in the opposite axial direction and supports it axially in a non-contact manner. By controlling the DC current based on the output signal of the position sensor, the axial position of the shaft (1) is controlled. The radial magnetic bearing (3) is composed of a stator portion (9) fixedly provided on the casing (7) and a rotor portion (10) fixedly provided on the shaft (1). The stator part (9) and the rotor part (10) have, for example, a resistivity of 5
It is a stack of silicon steel sheets having a thickness of 0 μΩ · cm.
The stator part (9) is formed with a plurality of stator magnetic poles (11) protruding inward in the radial direction. ) Is wrapped. By winding the attraction coil (13) around the magnetic pole (11), two pairs of electromagnets sandwiching the shaft (1) from both sides in two radial directions orthogonal to each other are formed. Although not shown, the casing near the radial magnetic bearing (3)
A radial position sensor for detecting the positions of the shaft (1) in the two radial directions is provided at an appropriate position in (7). Direct current is supplied to the suction coil (13) of the stator part (9), and three-phase alternating current is supplied to the motor coil (12).
By supplying DC current to the suction coil (13), each electromagnet attracts the shaft (1) outward in the radial direction and supports it in the radial direction in a non-contact manner. By controlling the current,
The radial position of the axis (1) is controlled. Further, by supplying an alternating current to the motor coil (12), a rotating magnetic field is generated to drive the shaft (1) to rotate, and by controlling the magnitude and frequency of this alternating current, the shaft (1) is rotated. The rotational driving force and the rotational speed of are controlled.

The structure of each part of the magnetic bearing device is not limited to that of the above-mentioned embodiment, but can be changed appropriately. For example, in the above embodiment, the two sets of radial magnetic bearings (3) and (4) are both motor-integrated magnetic bearings, but only one set may be a motor-integrated magnetic bearing.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of a magnetic bearing device showing an embodiment of the present invention.

[Explanation of symbols]

 (1) Rotating shaft (2) Axial magnetic bearing (3) (4) Radial magnetic bearing (11) Stator pole (12) Motor coil (13) Suction coil

Claims (1)

[Claims] 1. A plurality of sets of magnetic bearings for supporting a rotating shaft in a non-contact manner, wherein at least one set of magnetic bearings attracts said rotating shaft and a motor for rotationally driving said rotating shaft. A magnetic bearing device which is a motor-integrated magnetic bearing in which a coil is wound around a common stator magnetic pole, wherein the rotating shaft is made of soft magnetic stainless steel.