KR100643152B1 - Magnetic bearing actuator - Google Patents

Abstract

A magnetic bearing actuator is provided to prevent the same from being overheated by forming a drive source of a built-in BLDC motor. A magnetic bearing actuator includes a magnetic bearing unit(200) and a drive motor unit. The magnetic bearing unit rotatably supports a rotational shaft. The drive motor unit rotates the rotational shaft. The magnetic bearing unit includes a pair of radial magnetic bearings(210) and an axial magnetic bearing(220). The radial magnetic bearing is provided at both ends of the rotational shaft. The axial magnetic bearing is disposed between the radial magnetic bearings. The drive motor is disposed between one of the radial magnetic bearings and the axial magnetic beating.

Description

Magnetic Bearing Actuators {MAGNETIC BEARING ACTUATOR}

1 is a schematic cross-sectional view showing the magnetic bearing actuator according to the present invention by cutting in the longitudinal direction,

2 and 3 are a partial cutaway perspective view and a longitudinal cross-sectional view, respectively, shown in the longitudinal direction by extracting the rotary shaft assembly of the magnetic bearing actuator according to the present invention shown in FIG.

4 is a partially cutaway perspective view schematically illustrating an internal structure by longitudinally cutting the case assembly of the magnetic bearing actuator according to the present invention shown in FIG. 1;

FIG. 5 is a partial cutaway perspective view illustrating the coupling state of the case assembly and the rotating shaft assembly of the magnetic bearing actuator according to the present invention shown in FIG. 1;

6 is a cross-sectional view schematically showing an extract of the rotor assembly of the radial magnetic bearing of the magnetic bearing actuator according to the present invention shown in FIG.

7 is a perspective view schematically showing an extract of the rotor stator of the radial magnetic bearing of the magnetic bearing actuator shown in FIG. 1;

8 is a perspective view schematically showing an extract of the disk stator of the axial magnetic bearing of the magnetic bearing actuator according to the present invention shown in FIG.

9 is a cross-sectional view schematically showing the motor unit of the magnetic bearing actuator according to the present invention shown in FIG.

Explanation of symbols on the main parts of the drawings

100 ... case 110 ... rotation shaft

200 ... Magnetic Bearing Unit 210 ... Radial Magnetic Bearing

211 ... rotor assembly 211a ... rotor stand

211b ... rotor iron core 211c ... rotoring

220 ... axial magnetic bearing 221 ... trust disc

221a ... cylindrical body 221b ... rotor disc

300 ... motor unit 310 .... motor rotor

320 ... motor stator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magnetic bearings, and more particularly, to a magnetic-bearing actuator with a built-in drive motor, and in particular, an ultra-high speed small magnetic bearing that can be effectively applied to a small high-speed rotating body. It relates to an actuator (Magnetic Bearing Actuator).

The recent increase in the demand for high speed, high precision and high technology has led to the demand for high speed, high precision and high efficiency for the rotating technology of rotary machines. Magnetic bearings are widely known as one of the essential mechanical elements required for the production of such high speed, high precision rotary shafts.

These magnetic bearings are supported by a state in which the rotating shaft is floated without any physical contact through the change of the electromagnetic field using magnetic force.

Therefore, the magnetic bearing is capable of the exclusion of friction and the active control of the rotational trajectory during the rotation of the rotating shaft to enable the production of ultra-high speed, high-precision rotating shaft that can not be realized by the classic bearing such as conventional rolling element bearing. Due to the merits of such magnetic bearings, the research and development for the expansion of the scope of application is being actively conducted in recent years, but the development trends up to now are mainly the development of the medium and large magnetic bearings.

 In general, a magnetic bearing actuator includes a drive motor, a radial AMB (active magnetic bearing), an axial magnetic bearing (Axial AMB), a back-up bearing, and a case.

On the other hand, medium and large magnetic bearing actuators, which are mainly used, use a spindle motor of AC induction type as a driving source. Therefore, since the rotational force is obtained by the interaction between the magnetic field generated in the stator portion and the induction magnetic field generated in the rotor portion, the structure is simple and can have some constant speed.

However, the conventional medium-large magnetic bearing actuator as described above has a problem in that the service life and efficiency are lowered due to the heating problem of the winding and the durability problem due to the high speed as the induction motor is used as the driving source.

In addition, the existing medium-large size magnetic bearings have a problem that the price is high due to the installation of additives for the speed control of the induction motor used as a driving source, thereby degrading practicality and economical efficiency. I have a problem.

Accordingly, the present invention has been made in view of the problems with the conventional magnetic bearing actuator as described above, and an object of the present invention is to provide a magnetic bearing actuator having a more advantageous structure for high speed and miniaturization.

In order to achieve the above object, the magnetic bearing actuator according to the present invention includes a magnetic bearing unit for rotatably supporting a rotating shaft installed to be inserted into a hollow portion of a hollow case in a non-contact state, and for rotating the rotating shaft. In a magnetic bearing actuator comprising a drive motor unit, the magnetic bearing unit is a shaft provided so as to be arranged between a pair of radial magnetic bearings provided to be disposed at both ends of the rotary shaft and the respective radial magnetic bearings. And a directional magnetic bearing, wherein the drive motor is arranged to be disposed between any one of the pair of radial magnetic bearings and the axial magnetic bearing.

According to the present invention, the radial magnetic bearing is configured to include a rotor assembly provided on the rotating shaft and a rotor stator provided in the hollow portion of the case so as to face each other at a predetermined gap around the rotor assembly. .

The rotor assembly may include a cylindrical rotor stand coaxially coupled to an outer circumferential surface of the rotating shaft, a rotor iron core coaxially coupled to an outer circumferential surface of the rotor stand, and an outer circumferential surface of the rotor stand to constrain the rotor iron core. It is preferred to include a rotor ring that is coupled.

In addition, the rotor ring and the rotor stand is screwed to each other, the rotor stand is a screw thread is formed on the outer peripheral surface to form a male screw structure, the rotor ring is preferably formed a screw thread on the inner peripheral surface to form a female screw structure.

The rotor stator preferably comprises a donut-shaped ring member in which silicon steel sheets are stacked, a plurality of protrusions protruding toward the center of the inner diameter portion of the ring member, and coils wound around the protrusions to form a magnetic field. Do.

According to the present invention, the axial magnetic bearing includes a thrust disk installed on the rotating shaft and a thrust stator provided in the hollow portion of the case so as to face the thrust disk spaced apart at a predetermined gap. It is composed.

The thrust disc preferably includes a cylindrical body installed coaxially on the outer circumferential surface of the rotating shaft, and a rotor disc formed to radially extend and protrude from the center of the body.

Preferably, the thruster stator is formed of a pair of annular electromagnets provided in the hollow portion of the case so as to face the rotor disk spaced apart from each other by a predetermined gap.

The motor unit includes a magnet provided on the rotating shaft, and a motor stator provided to face the magnet at a predetermined gap.

In the magnetic bearing actuator according to the present invention having the configuration as described above, a pair of auxiliary bearings supporting the rotating shaft may be further provided on the outer side of the pair of radial magnetic bearings. In addition, the case is provided with a plurality of displacement sensors for detecting the radial displacement and the axial displacement of the rotation axis.

Hereinafter, with reference to the accompanying drawings will be described in detail a magnetic bearing actuator according to the present invention.

Referring to FIG. 1, the magnetic bearing actuator 10 according to the present invention includes a rotating shaft 110 installed to be inserted into a hollow portion of the hollow case 100, and the rotating shaft 110 floats in a non-contact state. And a magnetic bearing unit 200 for supporting the rotary shaft in a rotatable state, and a drive motor unit 300 for driving the rotary shaft 110 to rotate.

According to the present invention, the magnetic bearing unit 200 includes a pair of radial magnetic bearings 210 and axial magnetic bearings 220.

Each of the radial magnetic bearings 210 is provided to be located at both ends of the rotation shaft 110, as shown. In addition, the axial magnetic bearing 220 is provided to be located between the pair of radial magnetic bearing 210.

The drive motor unit 300 is provided to be disposed between the radial magnetic bearing 220 and the axial magnetic bearing 230.

That is, in the magnetic bearing actuator 10 according to the present invention, the rotor of the magnetic bearing unit 200 and the driving motor unit 300 are respectively installed using the rotating shaft 110 as a core member, so-called sub-assembly. (sub-assembly), the stator of the bearing unit 200 and the drive motor unit 300 are respectively installed in the case 100 to form a sub-assembly. This subassembly structure takes into account ease of assembly and processability. Here, reference numeral B of FIG. 1 denotes an auxiliary bearing installed for protection when the rotating shaft 110 is stopped, and assists the smooth rotation of the rotor before and after the function of the magnetic bearing when the actuator is driven. And, reference numeral C denotes a cap member coupled for completing the assembly of the magnetic bearing actuator according to the present invention. Reference numerals S1 and S2 denote displacement sensors for detecting displacements of the radial magnetic bearing 210 and the axial magnetic bearing 220, respectively. That is, the displacement sensors S1 and S2 respectively measure a displacement by detecting a gap formed between the rotor and the stator of the radial magnetic bearing 210 and the axial magnetic bearing 220.

2 and 3, the rotary shaft 110 includes a rotor assembly 211 of each of the radial magnetic bearings 210, a thrust disk 221 of the axial magnetic bearings 220, and the driving motor. The rotor magnets 310 of the unit 300 are respectively installed coaxially.

4, the rotor stator 212 of each of the radial magnetic bearings 210 and the thruster stator 222 of the axial magnetic bearings 220 are formed on the inner circumferential surface of the hollow part of the case 100, respectively. ) And the motor stator 320 of the driving motor unit 300 are respectively installed coaxially.

FIG. 5 is a diagram illustrating a state in which the rotating shaft 110 assembly and the case 100 sub-assembly are complementarily coupled to each other.

Referring to FIG. 5, each of the radial magnetic bearings 210 includes a rotor assembly 211 and a rotor stator 212.

The rotor assembly 211 is installed coaxially on the outer circumferential surface of the rotating shaft 110, the rotor stator 212 is spaced apart from the outer circumference of each rotor assembly 211 by a predetermined gap to face the case 100 Is provided on the inner peripheral surface of the hollow portion.

As shown in FIG. 6, the rotor assembly 211 has a cylindrical rotor stand 211a coupled to an outer circumferential surface of the rotary shaft 110, and a rotor iron core 211b coupled to an outer circumferential surface of each rotor stand 211a. And a rotor ring 211c coupled to the outer circumferential surface of the rotor stand 211a to constrain the rotor iron core 211b.

The displacement sensor S1 detects the displacement of the rotor ring 211c to detect the displacement of the radial magnetic bearing 210.

The rotor ring 211c and the rotor stand 211a are screwed together, and the rotor stand 211a has a male thread formed on its outer circumferential surface to form a male screw structure, and the rotor ring 211c has a screw thread formed on its inner circumferential surface. Complementary coupling is possible as the female screw structure is achieved. Magnetic bearing actuator according to the present invention has the advantage of having excellent assembly by this screw coupling structure.

As shown in FIG. 7, the rotor stator 212 protrudes from the inner diameter portion of the donut-shaped ring member 212a so that the plurality of salient poles 212b face the center portion, and forms a magnetic field in each salient pole 212b. Coil 212c is wound.

According to the present invention, the rotor stator 212 is composed of eight poles provided with eight protrusions 212b, and the ring member 212a has a structure in which a silicon steel sheet having a thickness of about 0.2 mm is laminated. This structure is for reducing losses at high speed.

The axial magnetic bearing 220 includes a thrust disk 221 and a thrust stator 222.

The thrust disk 221 is installed coaxially on the outer circumferential surface of the rotating shaft 110, the thrust stator 222 is spaced at a predetermined gap around the thrust disk 221 to face the case ( It is provided on the inner peripheral surface of the hollow part of 100).

2 and 5, the thrust disk 221b is formed so as to radially expand and protrude radially in the center of the cylindrical body 221a, which is coaxially installed on the outer circumferential surface of the rotation shaft 110, respectively. ).

As illustrated in FIG. 8, the thrust stator 222 is a pair of annular electromagnets 222a and 222b provided on the inner circumferential surface of the hollow part of the case 100 so as to face the rotor disc 221b at a predetermined gap. As a result, the displacement can be controlled by generating an action force in the axial direction of the rotary shaft 110, thereby preventing axial fluctuations.

That is, the magnetic bearing actuator according to the present invention is disposed at the end by arranging the thrust disc 221 and the thruster stator 222 at approximately the center of the rotation shaft 110 to form the axial magnetic bearing 220. Force is increased rather than to have excellent characteristics.

The driving motor unit 300 is a built-in type brushless DC (BLDC) motor, and includes a rotor magnet 310 and a motor stator 320 for forming a magnetic path.

As shown in FIG. 9, the rotor magnet 310 is coaxially installed on the outer circumferential surface of the rotation shaft 110, and the motor stator 320 is spaced apart at a predetermined gap around the rotor magnet 310 to face each other. It is provided. Here, reference numeral 301 of FIG. 9 denotes a circuit board for driving a motor.

According to the present invention, the rotor magnet 310 is made of a magnet of the Nd series, the motor stator 320 is made of a coil wound body having a back yoke (Back yoke) for the laminated structure of the silicon steel sheet and an effective ruler As such, this configuration does not limit the present invention. In addition, a sensorless controller may be applied to the control of the driving motor unit 300.

Hereinafter, an operation state of the magnetic bearing actuator according to the present invention having the configuration as described above with reference to the accompanying drawings will be described.

First, power is supplied to a controller (not shown) electrically connected to the magnetic bearing unit 200 to drive the magnetic bearing actuator according to the present invention. At this time, before the function of the magnetic bearing, the auxiliary bearing (B) assists the smooth rotation of the rotating shaft (110).

When power is supplied to the controller, the floating control of the radial magnetic bearing 210 and the axial magnetic bearing 220 constituting the magnetic bearing unit 200 starts. At this time, each of the displacement sensors S1 and S2 detects the floating position of the rotary shaft 110 and sends feedback to the controller as signal information. Accordingly, the controller supports the rotating shaft 110 in a state of being raised to a desired target position based on the received signal information.

As such, when electric power is supplied to the motor stator 320 of the driving motor unit 300 in a state in which the rotating shaft 110 is floated by the magnetic bearing unit 200, the rotating shaft 110 is generated by the torque generated from the motor rotor 310. 110 is a rotational movement.

At this time, the axial magnetic bearing 220 during the rotational movement of the rotary shaft 110 generates an action force in the axial direction of the rotary shaft 110 to prevent the axial fluctuations by controlling the displacement. That is, the magnetic bearing actuator according to the present invention is disposed at the end by arranging the thrust disc 221 and the thruster stator 222 at approximately the center of the rotation shaft 110 to form the axial magnetic bearing 220. Force is greatly increased than it is to have excellent characteristics.

As described above, according to the magnetic bearing actuator according to the present invention, the following effects can be obtained.

First, by constructing the drive source as a built-in type BLDC motor, it is possible to solve the heat problem caused by the winding, thereby increasing the degree of speed increase and at the same time to obtain the effect of durability and life extension, and to reduce the manufacturing cost. The effect can be obtained.

Secondly, the structure that is disposed at the center of the rotating shaft so that the axial magnetic bearing and the drive motor are located between the radial magnetic bearings can achieve an advantageous effect in miniaturization.

Third, since each rotor and the stator are assembled to form the sub-assembly of the rotating shaft and the case by the core member (core member), it is possible to obtain an effect excellent in assembly and workability.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes are intended to fall within the scope of the claims set forth.

Claims (11)

In the magnetic bearing actuator comprising a magnetic bearing unit for rotatably supporting a rotating shaft installed to be inserted into the hollow portion of the hollow case in a non-contact state, and a drive motor unit for rotating the rotating shaft. The magnetic bearing unit includes a pair of radial magnetic bearings arranged to be disposed at both ends of the rotation shaft, and an axial magnetic bearing provided to be disposed between the respective radial magnetic bearings, And the drive motor is arranged to be disposed between any one of the pair of radial magnetic bearings and the axial magnetic bearing. The method of claim 1, wherein the radial magnetic bearing, And a rotor stator provided on the hollow part of the case so as to face the rotor assembly installed on the rotating shaft and spaced apart from each other by a predetermined gap around the rotor assembly. The method of claim 2, wherein the rotor assembly, A cylindrical rotor stand coupled coaxially to the outer circumferential surface of the rotating shaft, And a rotor iron core coupled to the outer circumferential surface of the rotor stand coaxially. And a rotor ring coupled to an outer circumferential surface of the rotor stand to constrain the rotor iron core. The method of claim 3, wherein The rotor ring and the rotor stand are screwed to each other, the rotor stand has a screw thread formed on the outer peripheral surface to form a male screw structure, the rotor ring is a magnetic bearing actuator, characterized in that the female thread structure is formed by forming a thread on the inner peripheral surface. . The method of claim 2, The rotor stator includes a donut-shaped ring member in which silicon steel sheets are stacked, a plurality of salient poles protruding toward the center of the inner diameter of the ring member, and coils wound around the salient poles to form a magnetic field. Magnetic bearing actuator. The method of claim 1, wherein the axial magnetic bearing, A trust disk installed on the rotating shaft; And a thruster stator provided in the hollow portion of the case so as to face each other with a predetermined gap around the thrust disc. The method of claim 6, The thrust disk has a cylindrical body which is installed coaxially on the outer circumferential surface of the rotating shaft, and a rotor disk formed so as to radially extend and protrude in the center of the body. The method of claim 6, The thruster stator is a magnetic bearing actuator, characterized in that consisting of a pair of annular electromagnet provided in the hollow portion of the case so as to face the rotor disk spaced apart by a predetermined gap. The method of claim 1, wherein the motor unit, A magnet installed on the rotating shaft, And a motor stator provided so as to face each other with a predetermined gap around the magnet. The method of claim 1, The outer side of the pair of radial magnetic bearings, a pair of auxiliary bearings for supporting the rotation axis, respectively, characterized in that the magnetic bearing actuator. The method of claim 1, The case has a magnetic bearing actuator, characterized in that a plurality of displacement sensors are installed for detecting the radial displacement and the axial displacement of the rotation axis.

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