JP2018021573A - Diskless thrust magnetic bearing and three-axis active control magnetic bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diskless thrust magnetic bearing and a three-axis active control magnetic bearing that can restrain a reduction in thrust support force while shortening the axial length of a rotor.SOLUTION: A diskless thrust magnetic bearing 1A comprises: a rotor 10; a shared magnetic pole 21A arranged so as to be opposed to a peripheral surface 10c of the rotor 10; and a first thrust stator 30z1 and a second thrust stator 30z2 arranged so as to be opposed to each other across the shared magnetic pole 21A. The first thrust stator 30z1 comprises a first thrust stator magnetic pole 33z1 arranged so as to be opposed to one end surface 10a of the rotor 10. The second thrust stator 30z2 comprises a second thrust stator magnetic pole 33z2 arranged so as to be not opposed to another end surface of the rotor 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a diskless thrust magnetic bearing and a three-axis active control magnetic bearing.

  The magnetic bearing has advantages such as no wear due to mechanical contact and no need for a lubricant. Since this magnetic bearing has a small loss in the bearing, it is used in turbo molecular pumps, compressors, gas turbines, power storage flywheels and the like that rotate impellers and shafts at high speeds. Since the magnetic bearing supports the rotating body in a non-contact manner by electromagnetic force, in order to fix the rotating body in the space, it is necessary to control the motion with three degrees of freedom of translation, two degrees of freedom of inclination, and one degree of freedom of rotation. is there. Usually, the motor is responsible for one degree of freedom of rotation, and the remaining five degrees of freedom are controlled by magnetic bearings.

  Non-Patent Document 1 below discloses a basic configuration of a 5-degree-of-freedom control type magnetic bearing (see FIG. 1 of Non-Patent Document 1). This magnetic bearing is composed of two sets of radial magnetic bearings and one thrust bearing. A total of two radial magnetic bearings for controlling the motion in the translational direction of the shaft with two degrees of freedom are arranged at the end of the shaft, and control the motion in the translational direction with two degrees of freedom and the tilt with two degrees of freedom. A thrust bearing that generates a force in the direction of one degree of freedom controls the movement of one degree of freedom in the axial direction. The thrust bearing has a configuration in which a single magnetic disk (thrust disk) attached to a shaft is sandwiched between two ring-shaped electromagnets provided with coil grooves.

Tadahiko Shinji, “Magnetic Bearing Fundamentals and Applications”, Journal of Precision Engineering, Vol. 78, no. 12, 2012, p. 1054-1057

By the way, radial / thrust magnetic bearings are inferior in mechanical rigidity to mechanical bearings, so the system becomes large. At the same time, the shaft rigidity decreases as the shaft length increases, leading to a decrease in critical speed. In addition, since the thrust magnetic bearing is composed of a thrust disk and a pair of thrust stators sandwiching the thrust disk, there is a problem that the thrust stator and the rotor cannot be assembled and separated independently.
In order to solve this problem, the inventors of the present application have invented a diskless thrust magnetic bearing in which a pair of thrust stators are integrated to shorten the axial length of the rotor. However, when the diskless structure is adopted, the facing area related to the magnitude of the magnetic force becomes small, which causes a new problem that the thrust supporting force is reduced.

  The present invention has been made in view of the above problems, and is directed to a diskless thrust magnetic bearing and a three-axis active control magnetic bearing capable of suppressing a reduction in thrust support force while shortening the axial length of the rotor. For the purpose of provision.

  In order to solve the above-described problems, the present invention provides a rotor, a shared magnetic pole disposed to face the circumferential surface of the rotor, a first thrust stator disposed to face the shared magnetic pole, and A second thrust stator, wherein the first thrust stator has a first thrust stator magnetic pole disposed to face one end surface of the rotor, and the second thrust stator is A diskless thrust magnetic bearing having a second thrust stator magnetic pole disposed not facing the other end face of the rotor is employed.

  In the present invention, the first thrust stator has a first thrust winding, and the second thrust stator has a second thrust winding.

  In the present invention, the second thrust stator has a configuration in which the number of turns is larger than that of the first thrust winding.

  In the present invention, a configuration is adopted in which the magnetic resistance of the magnetic circuit formed by the second thrust winding is larger than that of the magnetic circuit formed by the first thrust winding.

  In the present invention, a configuration is adopted in which the second thrust winding is larger in the radial direction than the first thrust winding.

  In the present invention, a configuration is adopted in which the second thrust winding is larger in the axial direction than the first thrust winding.

  In the present invention, a configuration is adopted in which the thickness of the second thrust stator magnetic pole is thicker than the thickness of the first thrust stator magnetic pole.

  In the present invention, the rotor, the radial stator disposed to face the circumferential surface of the rotor, and the radial stator core of the radial stator that are disposed to face each other with the radial stator interposed therebetween are shared magnetic poles. The three-axis active control magnetic bearing having the first thrust stator and the second thrust stator of the diskless thrust magnetic bearing described in 1) is employed.

  Therefore, in the present invention, it is possible to suppress a reduction in thrust support force while shortening the axial length of the rotor.

1 is a longitudinal sectional view showing a diskless thrust magnetic bearing according to a first embodiment of the present invention. It is the principal part enlarged view which extracted and expanded the principal part of the diskless thrust magnetic bearing shown in FIG. It is a perspective view which shows the longitudinal cross-section of the magnetic bearing in 2nd Embodiment of this invention. It is a disassembled perspective view which shows the structure of the magnetic bearing in 2nd Embodiment of this invention. It is a cross-sectional view of the magnetic bearing which shows the structure of the radial stator in 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the magnetic bearing which shows the structure of the thrust stator in 2nd Embodiment of this invention. FIG. 4 is a longitudinal sectional view of a magnetic bearing showing a configuration of a thrust stator that forms a second magnetic circuit so that the directions of magnetic fluxes are different in radial stator poles as an example. 8 is a graph showing (a) a change in radial stator magnetic flux and (b) a change in support force of the radial stator when magnetic fluxes of a radial stator and a thrust stator are superimposed on the magnetic bearing shown in FIG. 7. As a comparative example, it is a longitudinal sectional view of a magnetic bearing showing the configuration of a thrust stator that forms a second magnetic circuit so that the directions of magnetic fluxes are the same in the radial stator magnetic poles. FIG. 10 is a graph showing (a) a change in the radial stator magnetic flux and (b) a change in the support force of the radial stator when the magnetic fluxes of the radial stator and the thrust stator are superimposed on the magnetic bearing shown in FIG. 9. It is a top view which shows the radial stator in another embodiment of this invention. It is a perspective view which shows the radial stator core shown in FIG. It is a top view which shows the radial stator in another embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are described by way of example for better understanding of the spirit of the invention, and do not limit the present invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, the main part may be enlarged for convenience, and the dimensional ratios of the respective components are the same as the actual ones. Not necessarily. In addition, in order to make the features of the present invention easier to understand, some parts are omitted for convenience.

(First embodiment)
FIG. 1 is a longitudinal sectional view showing a diskless thrust magnetic bearing 1A according to a first embodiment of the present invention. In the following description, an XYZ orthogonal coordinate system may be set, and the positional relationship of each member may be described with reference to this XYZ orthogonal coordinate system. Two axes orthogonal to each other in the radial direction are defined as an X-axis direction and a Y-axis direction, respectively, and one axis in the thrust direction is defined as a Z-axis direction. The Z-axis direction is orthogonal to the X-axis direction and the Y-axis direction.
As shown in FIG. 1, the diskless thrust magnetic bearing 1 </ b> A includes a rotor 10, a shared magnetic pole 21 </ b> A, and a thrust stator 30 that generates a supporting force in the thrust direction of the rotor 10.

The thrust stator 30 is provided facing the common magnetic pole 21A in the thrust direction, and controls one axis in the thrust direction.
In the following description, one of the paired thrust stators 30 is referred to as a first thrust stator 30z1, and the other is referred to as a second thrust stator 30z2.

The shared magnetic pole 21A, the first thrust stator 30z1, and the second thrust stator 30z2 are connected to each other and integrated. A hole 3 in which the rotor 10 is disposed is formed at the center of the diskless thrust magnetic bearing 1A.
The rotor 10 is a magnetic body and is formed in a cylindrical shape.
The shared magnetic pole 21A is a magnetic body and is formed in an annular shape. The shared magnetic pole 21 </ b> A is disposed outside the rotor 10 and faces the circumferential surface 10 c of the rotor 10 with a gap.

  The thrust stator 30 has a thrust stator core 31 and a thrust winding 32. The thrust stator 30 of this embodiment forms an electromagnet type homoporous last magnetic bearing. The thrust stator core 31 is a magnetic body and is connected to the shared magnetic pole 21A.

  The thrust stator core 31 is formed in a substantially bottomed cylindrical shape, and accommodates a thrust winding 32 therein. The thrust stator core 31 includes a disk-shaped thrust stator magnetic pole 33 with a hole formed in the center, and a cylindrical thrust stator back yoke 34 protruding from the peripheral edge of the thrust stator magnetic pole 33 toward the shared magnetic pole 21A. Have. The thrust stator back yoke 34 connects the thrust stator magnetic pole 33 and the shared magnetic pole 21A.

  The first thrust stator magnetic pole 33z1 of the first thrust stator 30z1 is formed with a thickness t1 smaller than the thickness t3 of the shared magnetic pole 21A. The second thrust stator magnetic pole 33z2 of the second thrust stator 30z2 is formed with a thickness t2 smaller than the thickness t3 of the shared magnetic pole 21A. The thickness t1 and the thickness t2 are equal, and the first thrust stator magnetic pole 33z1 and the second thrust stator magnetic pole 33z2 have a thickness of ½ or less of the shared magnetic pole 21A. Further, the outer diameters of the first thrust stator back yoke 34z1 of the first thrust stator 30z1 and the second thrust stator back yoke 34z2 of the second thrust stator 30z2 are formed to be equal.

  The thrust winding 32 forms a magnetic circuit 102 that passes through the thrust stator core 31, the rotor 10, and the shared magnetic pole 21A. That is, the magnetic flux (linkage magnetic flux) that forms the magnetic circuit 102 passes through the thrust stator magnetic pole 33, the thrust stator back yoke 34, the shared magnetic pole 21 </ b> A, and the rotor 10.

  The thrust stator 30 having the above-described configuration is provided facing the common magnetic pole 21A in the thrust direction, and the first thrust winding 32z1 of the first thrust stator 30z1 and the second of the second thrust stator 30z2. The thrust windings 32z2 are arranged to face each other in the Z-axis direction in which the rotor 10 extends. When a direct current is passed through each of the first thrust winding 32z1 and the second thrust winding 32z2, a magnetic attractive force derived from the magnetic flux accompanying the current is generated, and one axis in the thrust direction (Z-axis direction) is generated. Can be controlled.

Each of the first thrust stator 30z1 and the second thrust stator 30z2 forms magnetic circuits 102z1 and 102z2 that pass through the shared magnetic pole 21A. That is, the shared magnetic pole 21A serves as a shared magnetic path for the first thrust stator 30z1 and the second thrust stator 30z2.
The pair of first thrust stator 30z1 and second thrust stator 30z2 form magnetic circuits 102z1 and 102z2 so that the directions of magnetic fluxes are opposite to each other in the shared magnetic pole 21A.

  The polarities of the first thrust winding 32z1 and the second thrust winding 32z2 are selected to be opposite to each other in the shared magnetic pole 21A in order to suppress magnetic saturation in the shared magnetic pole 21A. For example, the magnetic circuit 102z1 formed by the first thrust winding 32z1 is counterclockwise, and the magnetic circuit 102z2 formed by the second thrust winding 32z2 is also counterclockwise. In the rotor 10, the direction of the magnetic flux by the first thrust winding 32z1 and the direction of the magnetic flux by the second thrust winding 32z2 are both directed to the + side in the Z-axis direction.

The first thrust stator 30z1 has a first thrust stator magnetic pole 33z1 disposed to face one end face 10a of the rotor 10. The inner diameter of the annular first thrust stator magnetic pole 33 z 1 is smaller than the outer diameter of the rotor 10 and larger than the inner diameter of the rotor 10.
Further, the second thrust stator 30z2 has a second thrust stator magnetic pole 33z2 disposed so as not to face the other end face 10b of the rotor 10. The inner diameter of the annular second thrust stator magnetic pole 33 z 2 is larger than the outer diameter of the rotor 10.

  The second thrust stator 30z2 includes a second thrust winding 32z2 having a larger number of turns than the first thrust winding 32z1. The width w2 of the second thrust winding 32z2 is the same as the width w1 of the first thrust winding 32z1, but the second thrust winding 32z2 is larger in the radial direction than the first thrust winding 32z1. It has become. That is, the outer diameter r2 of the second thrust winding 32z2 is larger than the outer diameter r1 of the first thrust winding 32z1. Since the outer diameter r1 and the outer diameter r2 are different, the magnetic circuit 102z1 and the magnetic circuit 102z2 are different. Since the outer diameter r2 is larger than the outer diameter r1, the magnetic resistance of the magnetic circuit 102z2 is larger than the magnetic resistance of the magnetic circuit 102z1. The widths w1 and w2 and the outer diameters r1 and r2 of the thrust windings 32z1 and 32z2 are the width and outer diameter of the winding area in the longitudinal sectional view (FIG. 1) of the diskless thrust magnetic bearing 1A.

Next, the function and effect of the diskless thrust magnetic bearing 1A having the above configuration will be described with reference to FIG.
FIG. 2 is an enlarged view of a main part extracted from the main part of the diskless thrust magnetic bearing 1A shown in FIG. 1 and enlarged.

  In the diskless thrust magnetic bearing 1A having the above-described configuration, as shown in FIG. 1, the support force in the thrust direction of the rotor 10 is generated by a magnetic attractive force derived from the magnetic flux accompanying the current flowing through the thrust winding 32 of the thrust stator 30. . The thrust stator core 31 is connected to the shared magnetic pole 21A, and this magnetic flux forms a magnetic circuit 102 that passes through the thrust stator core 31, the rotor 10, and the shared magnetic pole 21A. That is, the shared magnetic pole 21A is arranged between the first thrust stator 30z1 and the second thrust stator 30z2, and the shared magnetic pole 21A is connected to the shared magnetic path of the first thrust stator 30z1 and the second thrust stator 30z2. By doing so, the first thrust stator 30z1 and the second thrust stator 30z2 can be integrated to save space in the axial direction.

  In the present embodiment, the first thrust stator magnetic pole 33z1 of the first thrust stator 30z1 is disposed so as to face the one end surface 10a of the rotor 10, so that the magnetic force f acts as shown in FIG. A large area S1 can be secured. For this reason, the thrust support force can be improved. On the other hand, since the second thrust stator magnetic pole 33z2 of the second thrust stator 30z2 is disposed so as not to face the other end face 10b of the rotor 10, the thrust stator and the rotor 10 are assembled and disassembled independently. Can do. That is, according to this configuration, the rotor 10 can be inserted and removed without interfering with the second thrust stator magnetic pole 33z2.

  As shown in FIG. 2, in the first thrust stator 30z1, since the first thrust stator magnetic pole 33z1 faces one end surface 10a of the rotor 10, the magnetic force f is directly applied to the area S1 as a thrust support force. Works. For this reason, even if it is a case where it is a diskless structure, thrust support force can be improved.

  On the other hand, in the second thrust stator 30z2, since the second thrust stator magnetic pole 33z2 is not opposed to the other end face 10b of the rotor 10, the area S2 on which the magnetic force f acts (the tip of the second thrust stator magnetic pole 33z2). Is considered to be substantially the same as the projected area of (1). Further, the magnetic force f is decomposed into a thrust component force f1 and a radial component force f2.

Thus, since the thrust supporting force of the second thrust stator 30z2 is smaller than the thrust supporting force of the first thrust stator 30z1, in this embodiment, as shown in FIG. 1, to correct this imbalance. In addition, the number of turns of the second thrust winding 32z2 is larger than that of the first thrust winding 32z1.
That is, the magnetic force f can be expressed by the following formula (1). B is the magnetic flux density, S is the area, and μ ₀ is the vacuum permeability.

  Here, B = μH. μ is the magnetic permeability, and H is the strength of the magnetic field. H is a value proportional to the number of turns of the coil. Therefore, by making the number of turns of the second thrust winding 32z2 larger than the number of turns of the first thrust winding 32z1, the thrust supporting force of the first thrust stator 30z1 and the second thrust stator 30z2 It is possible to achieve a balance with the thrust support force.

  In the present embodiment, as shown in FIG. 1, the second thrust winding 32z2 is made larger in the radial direction than the first thrust winding 32z1. According to this configuration, even if the number of turns of the second thrust winding 32z2 is increased, the width w2 does not change, so that space saving in the axial direction can be achieved. In FIG. 1, the difference in the radial direction between the first thrust winding 32z1 and the second thrust winding 32z2 is exaggerated, but the magnetic force f is the same as that of the thrust winding 32 as described above. Since the effect is obtained by the square of the number of turns, the difference in size between the first thrust winding 32z1 and the second thrust winding 32z2 is not so large.

According to the equation (1), since the magnetic force f can be increased by the number of turns and the area S of the thrust winding 32, a configuration in which the first thrust stator magnetic pole 33z1 is not opposed to one end face 10a of the rotor 10 is also adopted. However, if the first thrust stator magnetic pole 33z1 is not opposed to one end face 10a of the rotor 10, the corner of the thrust stator magnetic pole 33 is the same as the second thrust stator 30z2 shown in FIG. Magnetic flux is concentrated, magnetic saturation occurs, and the thrust support force converges no matter how much the current is increased. That is, there is an advantage that the potential of the thrust support force can be improved by making the first thrust stator magnetic pole 33z1 face the one end face 10a of the rotor 10 as in the present embodiment.
On the second thrust stator 30z2 side, the thickness of the second thrust stator magnetic pole 33z2 may be made thicker than the thickness of the first thrust stator magnetic pole 33z1 in order to suppress magnetic saturation. That is, you may comprise so that it may have the relationship of thickness t1 <thickness t2. Due to the difference in thickness between the first thrust stator magnetic pole 33z1 and the second thrust stator magnetic pole 33z2, the magnetic circuit 102z1 and the magnetic circuit 102z2 are different. Since the thickness of the second thrust stator magnetic pole 33z2 is thicker than that of the first thrust stator magnetic pole 33z1, the magnetic resistance of the magnetic circuit 102z2 becomes larger than the magnetic resistance of the magnetic circuit 102z1.

  Thus, according to the above-described embodiment, the rotor 10, the shared magnetic pole 21A disposed to face the peripheral surface 10c of the rotor 10, and the first disposed to face the shared magnetic pole 21A are disposed. The first thrust stator 30z1 has a first thrust stator magnetic pole 33z1 disposed opposite to one end face 10a of the rotor 10, and has a thrust stator 30z1 and a second thrust stator 30z2. The second thrust stator 30z2 has a second thrust stator magnetic pole 33z2 disposed so as not to face the other end face 10b of the rotor 10. That is, the shared magnetic pole 21A is disposed between the first thrust stator 30z1 and the second thrust stator 30z2 that are disposed to face each other, the shared magnetic pole 21A is opposed to the circumferential surface of the rotor 10, and the first The magnetic path is shared by the thrust stator 30z1 and the second thrust stator 30z2. As a result, the first thrust stator 30z1 and the second thrust stator 30z2 can be integrated to save space in the axial direction. Therefore, the axial length of the rotor 10 can be shortened.

  In the present embodiment, the first thrust stator magnetic pole 33z1 of the first thrust stator 30z1 is disposed to face one end face of the rotor 10, thereby ensuring a large area facing the rotor 10 and the thrust. The support force can be improved. That is, it is possible to suppress a decrease in thrust support force.

  Further, since the second thrust stator magnetic pole 33z2 of the second thrust stator 30z2 is disposed so as not to face the other end face of the rotor 10, assembly and disassembly of the thrust stators 30z1 and 30z2 and the rotor 10 are performed independently. It can be carried out. That is, it is possible to improve assembly / disassembly.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is simplified or omitted.

FIG. 3 is a perspective view showing a longitudinal sectional structure of the magnetic bearing 1 according to the second embodiment of the present invention. FIG. 4 is an exploded perspective view showing the configuration of the magnetic bearing 1 in the second embodiment of the present invention. In order to improve visibility, the rotor 10 shown in FIG. 4 is not shown in FIG. In FIG. 4, the housing 2 shown in FIG. 3 is not shown.
3 and 4, the magnetic bearing 1 includes a rotor 10, a radial stator 20 that generates a supporting force in the radial direction of the rotor 10, and a thrust stator 30 that generates a supporting force in the thrust direction of the rotor 10. Have. The rotor 10 is a magnetic body and is formed in a cylindrical shape.

The magnetic bearing 1 of this embodiment is a three-axis active control magnetic bearing. That is, the radial stator 20 controls two axes in the radial direction. The thrust stator 30 is provided opposite to the radial stator 20 in the thrust direction, and controls one axis in the thrust direction.
In the following description, one of the pair of thrust stators 30 is referred to as a thrust stator 30z1, and the other is referred to as a thrust stator 30z2.

  The radial stator 20, the first thrust stator 30 z 1, and the second thrust stator 30 z 2 are accommodated integrally inside the housing 2. A hole 3 in which the rotor 10 is disposed is formed in the center of the housing 2. The housing 2 includes a cylindrical portion 2a and a pair of lid portions 2b. The cylindrical portion 2a is formed in a cylindrical shape, and is fitted to the outer peripheral surfaces of the radial stator 20, the first thrust stator 30z1, and the second thrust stator 30z2. The pair of lid portions 2b are connected to both ends of the cylindrical portion 2a and cover the end faces of the first thrust stator 30z1 and the second thrust stator 30z2. The housing 2 is a nonmagnetic material and is made of stainless steel or the like.

FIG. 5 is a cross-sectional view of the magnetic bearing 1 showing the configuration of the radial stator 20 according to the second embodiment of the present invention. In the following description, an XYZ orthogonal coordinate system may be set, and the positional relationship of each member may be described with reference to this XYZ orthogonal coordinate system. Two axes orthogonal to each other in the radial direction are defined as an X-axis direction and a Y-axis direction, respectively, and one axis in the thrust direction is defined as a Z-axis direction. The Z-axis direction is orthogonal to the X-axis direction and the Y-axis direction.
As shown in FIG. 5, the radial stator 20 includes a radial stator core 21 corresponding to the shared magnetic pole 21 </ b> A and a radial winding 22. The radial stator 20 of this embodiment forms an electromagnet type heteropolar radial magnetic bearing.

  The radial stator core 21 is a magnetic body, and includes a plurality of radial stator magnetic poles 23 around which the radial windings 22 are wound, and a radial stator back yoke 24 that connects the plurality of radial stator magnetic poles 23. The radial stator back yoke 24 is formed in an annular shape and is disposed outside the rotor 10. The radial stator magnetic pole 23 protrudes from the inner peripheral surface of the radial stator back yoke 24 toward the outer peripheral surface of the rotor 10.

  The radial stator magnetic pole 23 is opposed to the outer peripheral surface of the rotor 10 with a gap. In the present embodiment, eight radial stator magnetic poles 23 are provided at 45 ° intervals in the circumferential direction of the rotor 10. The radial winding 22 is wound around the radial stator pole 23 using a slot opening formed between the radial stator poles 23 adjacent in the circumferential direction. The radial winding 22 is wound as a set of two radial stator magnetic poles 23 adjacent in the circumferential direction.

  Specifically, a radial winding 22x1 is wound around a pair of radial stator magnetic poles 23x1 adjacent in the circumferential direction. Further, a radial winding 22x2 is wound around a pair of radial stator magnetic poles 23x2 adjacent in the circumferential direction. A radial winding 22y1 is wound around each pair of radial stator magnetic poles 23y1 adjacent in the circumferential direction. A radial winding 22y2 is wound around each pair of radial stator magnetic poles 23y2 adjacent in the circumferential direction.

  The radial windings 22x1, 22x2, 22y1, and 22y2 form the first magnetic circuit 101 that passes through the radial stator core 21 and the rotor 10, respectively. The magnetic flux (linkage magnetic flux) forming the first magnetic circuit 101 is a pair of radial stator magnetic poles 23 around which the radial windings 22 are wound, and a radial connecting the two sets of radial stator magnetic poles 23. Via the stator back yoke 24 and the rotor 10.

  The radial windings 22 x 1 and 22 x 2 are arranged in pairs in the X-axis direction passing through the center of the rotor 10. When a direct current is supplied to each of the radial windings 22x1 and 22x2, a magnetic attractive force derived from the magnetic flux accompanying the current is generated, and one axis in the radial direction (X-axis direction) can be controlled.

  Further, the radial windings 22 y 1 and 22 y 2 are arranged in pairs in the Y-axis direction passing through the center of the rotor 10. When a direct current is passed through each of the radial windings 22y1 and 22y2, a magnetic attractive force derived from the magnetic flux accompanying the current is generated, and the other axis in the radial direction (Y-axis direction) can be controlled.

  The radial windings 22x1, 22x2, 22y1, and 22y2 are selected so that the adjacent magnetic fluxes are in opposite directions to prevent short-circuiting of the magnetic flux. For example, the first magnetic circuit 101 formed by the radial windings 22x1 and 22x2 is counterclockwise, and the first magnetic circuit 101 formed by the radial windings 22y1 and 22y2 is clockwise. The polarities of these radial stator magnetic poles 23 are alternately arranged in the order of N pole → N pole → S pole → S pole → N pole → N pole → S pole.

FIG. 6 is a longitudinal sectional view of the magnetic bearing 1 showing the configuration of the thrust stator 30 according to the second embodiment of the present invention.
As shown in FIG. 5, the thrust stator 30 includes a thrust stator core 31 and a thrust winding 32. The thrust stator 30 of this embodiment forms an electromagnet type homoporous last magnetic bearing. The thrust stator core 31 is a magnetic body and is connected to the radial stator core 21.

  The thrust stator core 31 is formed in a substantially bottomed cylindrical shape, and accommodates a thrust winding 32 therein. The thrust stator core 31 includes a disk-shaped thrust stator magnetic pole 33 in which a hole for disposing the rotor 10 is formed in the center, and a cylindrical thrust stator back yoke that protrudes from the peripheral edge of the thrust stator magnetic pole 33 toward the radial stator core 21. 34. The thrust stator back yoke 34 connects between the thrust stator magnetic pole 33 and the radial stator core 21, and the tip thereof is connected to the radial stator back yoke 24.

  The thrust stator magnetic pole 33 is formed with a thickness smaller than that of the radial stator magnetic pole 23 in a cross-sectional view shown in FIG. The thrust stator magnetic pole 33 of the present embodiment has a thickness that is 1/2 or less that of the radial stator magnetic pole 23. Further, the thrust stator back yoke 34 is formed with a thickness smaller than that of the radial stator back yoke 24 (from the outer periphery of the radial stator core 21 to the radial winding 22) in a sectional view shown in FIG. The thrust stator back yoke 34 of the present embodiment has a thickness that is ¼ or less of the radial stator back yoke 24. The outer diameters of the thrust stator back yoke 34 and the radial stator back yoke 24 are formed to be equal.

  The thrust stator magnetic pole 33 is disposed with a first space 201 in the thrust direction with respect to the radial winding 22. Further, the thrust stator back yoke 34 is disposed with a second space 202 in the radial direction with respect to the radial winding 22. A thrust winding 32 is arranged in the first space 201 and the second space 202. The thrust winding 32 is wound around the Z axis, and is formed into a ring shape with an L-shaped cross section (see FIG. 4) that covers the side surface and the upper surface of the radial winding 22.

  Here, the second thrust winding 32z2 has a larger number of turns than the first thrust winding 32z1, and is formed larger in the axial direction than the first thrust winding 32z1. That is, the second thrust stator magnetic pole 33z2 arranged not to face the other end face 10b of the rotor 10 is more than the first thrust stator magnetic pole 33z1 arranged facing the one end face 10a of the rotor 10. The first space 201 is large. The magnetic circuit 102z1 and the magnetic circuit 102z2 are different due to the difference in the axial direction between the first thrust winding 32z1 and the second thrust winding 32z2. Since the number of turns of the second thrust winding 32z2 is larger than that of the first thrust winding 32z1, the magnetic resistance of the magnetic circuit 102z2 becomes larger than the magnetic resistance of the magnetic circuit 102z1. According to this configuration, the imbalance between the thrust support force of the first thrust stator 30z1 and the thrust support force of the second thrust stator 30z2 can be corrected. Further, according to this configuration, as shown in FIG. 1, it is not necessary to increase the thickness of the first thrust stator back yoke 34z1, which can contribute to the reduction in size and weight in the radial direction.

  As shown in FIG. 6, the thrust winding 32 forms a second magnetic circuit 102 that passes through the thrust stator core 31, the rotor 10, and the radial stator core 21. Magnetic flux (interlinkage magnetic flux) that forms the second magnetic circuit 102 passes through the thrust stator magnetic pole 33, the thrust stator back yoke 34, the radial stator back yoke 24, the radial stator magnetic pole 23, and the rotor 10.

  The thrust stator 30 having the above-described configuration is provided facing the radial stator 20 in the thrust direction, and the first thrust winding 32z1 of the first thrust stator 30z1 and the second of the first thrust stator 30z1. The thrust windings 32z2 are arranged in pairs in the Z-axis direction in which the rotor 10 extends. When a direct current is passed through each of the thrust windings 32z1 and 32z2, a magnetic attractive force derived from the magnetic flux accompanying the current is generated, and one axis in the thrust direction (Z-axis direction) can be controlled.

Each of the first thrust stator 30 z 1 and the second thrust stator 30 z 2 forms second magnetic circuits 102 z 1 and 102 z 2 that pass through the radial stator magnetic pole 23. That is, the radial stator magnetic pole 23 is a magnetic path of the radial stator 20 and a shared magnetic path of the first thrust stator 30z1 and the second thrust stator 30z2.
Further, as shown in FIG. 6, the first thrust stator 30z1 and the second thrust stator 30z2 form second magnetic circuits 102z1 and 102z2 so that the directions of magnetic fluxes are opposite to each other in the radial stator magnetic pole 23. doing.

  The thrust windings 32z1 and 32z2 are selected to have opposite polarities in the radial stator pole 23 in order to suppress magnetic saturation in the radial stator pole 23. For example, the second magnetic circuit 102z1 formed by the thrust winding 32z1 is clockwise, and the second magnetic circuit 102z2 formed by the thrust winding 32z2 is also clockwise. In the rotor 10, the direction of the magnetic flux by the thrust winding 32z1 and the direction of the magnetic flux by the thrust winding 32z2 are both directed to the + side in the Z-axis direction.

FIG. 7 is a longitudinal sectional view of the magnetic bearing 1 showing the configuration of the thrust stator 30 that forms the second magnetic circuits 102z1 and 102z2 so that the directions of the magnetic fluxes are different in the radial stator magnetic pole 23 as an example. . FIG. 8 is a graph showing (a) a change in the radial stator magnetic flux and (b) a change in the supporting force of the radial stator 20 when the magnetic fluxes of the radial stator 20 and the thrust stator 30 are superimposed on the magnetic bearing 1 shown in FIG. is there.
FIG. 8A shows that the bias currents i _zb = 0, i _zb = 1.0, and i _zb = 2.0 are given to the thrust windings 32z1 and 32z2, and the control current i _xc of the radial winding 22 is increased. 7 shows a change in the magnetic flux φ _x1 in the radial stator magnetic pole 23 (region 300 shown in FIG. 7). Further, FIG. 8 (b) shows a change in the supporting force f _x of the radial stator 20 at this time.

As shown in FIG. 8A, when bias currents i _zb = 0, i _zb = 1.0, and i _zb = 2.0 are applied to the thrust windings 32z1 and 32z2, the magnetic flux φ _x1 It increases in proportion to i _xc . Further, as shown in FIG. 8B, the support force f _x also increases in proportion to the control current i _xc . As described above, in the magnetic bearing 1 shown in FIG. 7, even if the magnetic fluxes of the radial stator 20 and the thrust stator 30 are superimposed, magnetic saturation is not confirmed, and there is no change in the magnetic flux of the radial stator 20 due to the magnetic flux of the thrust stator 30 ( It can be seen that there is no interference.

  FIG. 9 is a longitudinal sectional view of a magnetic bearing 1 showing a configuration of a thrust stator 30 that forms the second magnetic circuits 102z1 and 102z2 so that the directions of magnetic fluxes are the same in the radial stator magnetic pole 23 as a comparative example. . FIG. 10 is a graph showing (a) a change in the radial stator magnetic flux and (b) a change in the support force of the radial stator when the magnetic fluxes of the radial stator 20 and the thrust stator 30 are superimposed on the magnetic bearing 1 shown in FIG. .

  In the thrust windings 32z1 and 32z2 shown in FIG. 9, the polarities are selected so that they are in the same direction in the radial stator magnetic pole 23, contrary to the configuration shown in FIG. For example, the second magnetic circuit 102z1 formed by the thrust winding 32z1 is clockwise, and the second magnetic circuit 102z2 formed by the thrust winding 32z2 is counterclockwise. In the rotor 10, the direction of the magnetic flux by the thrust winding 32z1 and the direction of the magnetic flux by the thrust winding 32z2 are opposite to each other in the Z-axis direction.

As shown in FIG. 10A, when a small bias current (i _zb = 0, i _zb = 1.0) is applied to the thrust windings 32z1 and 32z2, the magnetic flux φ _x1 is proportional to the control current i _xc. Although increasing, when a large bias current (i _zb = 2.0) is applied, the magnetic flux φ _x1 is not proportional to the control current i _xc = 1.5, and the gradient gradually decreases (converges). As shown in FIG. 10B, when a large bias current (i _zb = 2.0) is applied, the inclination of the supporting force f _x gradually decreases (converges) in the same manner as the magnetic flux φ _x1. . As described above, in the magnetic bearing 1 shown in FIG. 9, magnetic saturation occurs as a result of superimposing the magnetic fluxes of the radial stator 20 and the thrust stator 30, and a magnetic flux change of the radial stator 20 due to the magnetic flux of the thrust stator 30 occurs. I understand).

Then, the effect of the magnetic bearing 1 of the said structure is demonstrated.
In the magnetic bearing 1 having the above-described configuration, the support force in the radial direction of the rotor 10 is generated by the magnetic attractive force derived from the magnetic flux accompanying the current flowing through the radial winding 22 of the radial stator 20. As shown in FIG. 5, the magnetic flux forms a first magnetic circuit 101 that passes through the radial stator core 21 and the rotor 10. In the present embodiment, the support force in the thrust direction of the rotor 10 is generated by a magnetic attractive force derived from the magnetic flux accompanying the current flowing through the thrust winding 32 of the thrust stator 30. The thrust stator core 31 is connected to the radial stator core 21, and this magnetic flux forms a second magnetic circuit 102 that passes through the thrust stator core 31, the rotor 10, and the radial stator core 21 as shown in FIG. 6. Thus, in this embodiment, since the thrust stator core 31 is connected to the radial stator core 21 and the magnetic path of the radial stator 20 and the thrust stator 30 is shared, the radial stator 20 and the thrust stator 30 are integrated into the axial direction. Can be saved.

  In the present embodiment, the thrust stator 30 is provided opposite to the radial stator 20 in the thrust direction. According to this configuration, a total of three magnetic bearings of the radial stator 20, the first thrust stator 30z1, and the second thrust stator 30z2 can be integrated to save space in the axial direction.

  In the present embodiment, as shown in FIG. 6, the radial stator core 21 has a radial stator magnetic pole 23 around which a radial winding 22 is wound, and includes a first thrust stator 30z1 and a second thrust stator 30z2. Each forms the second magnetic circuit 102z1 and 102z2 via the radial stator pole 23. According to this configuration, the existing radial stator magnetic pole 23, which is the magnetic path of the radial stator 20, serves as a shared magnetic path for the first thrust stator 30z1 and the second thrust stator 30z2, and therefore a shared magnetic path is separately provided. There is no need to provide this, which can contribute to space saving in the axial direction.

  Furthermore, in the present embodiment, the first thrust stator 30z1 and the second thrust stator 30z2 form the second magnetic circuits 102z1 and 102z2 so that the directions of the magnetic fluxes are opposite to each other in the radial stator magnetic pole 23. . According to this configuration, the polarities can be selected so that the radial directions of the radial stator magnetic poles 23 are opposite to each other, and magnetic saturation in the radial stator magnetic poles 23 can be suppressed as shown in FIG. For this reason, even when the radial stator magnetic pole 23 that is the magnetic path of the radial stator 20 is a shared magnetic path of the first thrust stator 30z1 and the second thrust stator 30z2, magnetic saturation is suppressed, and the magnetic flux And the fall of supporting force can be controlled.

  In the present embodiment, as shown in FIG. 6, the thrust stator core 31 includes a thrust stator magnetic pole 33 disposed with a first space 201 in the thrust direction with respect to the radial winding 22, and a thrust stator magnetic pole 33. A thrust stator back yoke 34 which is connected to the radial stator core 21 and is disposed with a second space 202 in the radial direction with respect to the radial winding 22. Arranged in the space 201 and the second space 202. According to this configuration, the thrust winding 32 can be arranged by using a dead space (the first space 201 and the second space 202) having an L-shaped cross section between the radial stator core 21 and the thrust stator core 31. This can contribute to space saving in the axial direction.

  As described above, according to the above-described embodiment, the radial stator core of the radial stator is arranged so as to face the rotor 10, the radial stator arranged to face the circumferential surface 10c of the rotor 10, and the radial stator. By adopting a configuration in which the first magnetic stator 21z and the second thrust stator 30z2 of the diskless thrust magnetic bearing 1A described above are used as the shared magnetic pole 21A, the radial stator 20 and the thrust stator 30 are provided. The axial length of the rotor 10 can be shortened compared to the case where the radial stator 20 and the thrust stator 30 are individually arranged. Further, it is possible to suppress a decrease in thrust support force and to improve the assembling / disassembling property.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, the present invention can adopt forms as shown in FIGS. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 11 is a plan view showing a radial stator 20 according to another embodiment of the present invention. 12 is a perspective view showing the radial stator core 21 shown in FIG.
A radial stator 20 shown in FIG. 11 has a radial stator core 21 in which a groove 26 is formed in a radial stator back yoke 24. The groove 26 is formed so as to cross the inter-magnetic pole connecting portion 25 of the radial stator back yoke 24.

  The groove 26 is formed in the inter-magnetic pole connecting portion 25 where the first magnetic circuit 101 is not formed. Specifically, the inter-magnetic pole connecting portion 25 between the radial stator magnetic poles 23x1 and 23y2, and the magnetic pole between the radial stator magnetic poles 23y2 and 23x2. The inter-connection portion 25, the inter-magnetic pole connection portion 25 between the radial stator magnetic poles 23x2 and 23y1, and the inter-magnetic pole connection portion 25 between the radial stator magnetic poles 23y1 and 23x1 are formed. As shown in FIG. 12, the groove 26 is formed in the front surface 24a and the back surface 24b of the radial stator back yoke 24 at a predetermined depth, and extends linearly in the radial direction.

  A lead wire 40 of at least one of the radial winding 22 and the thrust winding 32 is disposed in the groove 26. In the embodiment shown in FIG. 11, two lead wires 40r of the radial winding 22 are arranged in the groove 26 between the radial stator magnetic poles 23x1, 23y2 and the groove 26 between the radial stator magnetic poles 23x2, 23y1. Further, in the groove 26 between the radial stator magnetic poles 23y1, 23x1 and the groove 26 between the radial stator magnetic poles 23y1, 23y2, two lead wires 40r of the radial winding 22 and one lead wire 40t of the thrust winding 32 are provided. A total of three are arranged. Although the arrangement of the lead wires 40 on the front surface 24a and the back surface 24b may be the same or different, it is preferable that two or three lead wires 40 are arranged in the groove 26.

  As described above, the radial stator core 21 includes a plurality of radial stator magnetic poles 23 around which the radial windings 22 are wound, and a radial stator back yoke 24 that connects the plurality of radial stator magnetic poles 23. The stator back yoke 24 has a groove 26 that crosses the inter-magnetic pole connecting portion 25 in the inter-magnetic pole connecting portion 25 where the first magnetic circuit 101 is not formed. As described above, by forming the groove 26 in the radial stator core 21, eddy currents generated in the radial stator core 21 can be suppressed. Moreover, since the groove | channel 26 is formed in the connection part 25 between magnetic poles in which the 1st magnetic circuit 101 is not formed, the magnetic path of the 1st magnetic circuit 101 does not become thin, and can suppress magnetic saturation.

  Further, at least one of the radial winding 22 and the thrust winding 32 is disposed in the groove 26. According to this configuration, the eddy current suppressing groove 26 can also be used as a lead wire groove for drawing out the lead wire 40 of the radial winding 22 and the thrust winding 32.

  Further, two or three lead wires 40 are arranged in the groove 26. In the present embodiment, since there are eight radial stator magnetic poles 23, there are a total of 16 lead wires 40r of the radial winding 22, and the thrust stator 30 is provided as a pair. There are a total of four lead wires 40t of 32. On the other hand, there are a total of eight grooves 26 on the front surface 24a and the back surface 24b. As in this embodiment, when two lead wires 40r are equally arranged in each of the eight grooves 26 on the front and back sides, the two lead wires 40t of the thrust winding 32 arranged on the surface 24a side are four on the surface 24a side. The two lead wires 40t of the thrust winding 32 disposed in any one of the two grooves 26 and disposed on the back surface 24b side must be disposed in any of the four grooves 26 on the back surface 24b side. Here, the two lead wires 40t of the thrust winding 32 may be arranged in one groove 26 (a total of four lead wires 40 may be arranged in one groove 26). Accordingly, the groove 26 must be formed larger, and the mechanical strength of the radial stator core 21 becomes weaker. For this reason, in the present embodiment, the two lead wires 40t of the thrust winding 32 are arranged in separate grooves 26, and a maximum of three lead wires 40 are drawn from the grooves 26, so that the machine of the radial stator core 21 Secures strength.

FIG. 13 is a plan view showing a radial stator 20 according to another embodiment of the present invention. In FIG. 13, the lead wire 40 is not shown in order to improve visibility.
As in the modification shown in FIG. 13, the grooves 26a formed on the front surface 24a and the grooves 26b formed on the back surface 24b may be offset. According to this configuration, since the grooves 26a and 26b are not formed to face each other in the thickness direction, the thickness in the grooves 26a and 26b is larger than that in the embodiment shown in FIG. 11, and the mechanical strength of the radial stator core 21 is increased. Can do.

  Further, for example, in the above embodiment, the configuration of only the electromagnet has been described, but a permanent magnet may be added to the configuration. For example, the permanent magnet can be inserted into the thrust stator back yoke 34 or the like.

  In addition, the configurations of the above embodiments can be applied in appropriate combinations within a range that does not depart from the gist of the present invention.

1 Magnetic bearing (3-axis active control magnetic bearing)
1A diskless thrust magnetic bearing 10 rotor 10a one end face 10b other end face 10c peripheral face 20 radial stator 21 radial stator core (shared magnetic pole)
21A Shared magnetic pole 30z1 First thrust stator 30z2 Second thrust stator 31z1 First thrust stator core 31z2 Second thrust stator core 32z1 First thrust winding 32z2 Second thrust winding 33z1 First thrust stator pole 33z2 First 2 Thrust stator poles

Claims (8)

A rotor,
A shared magnetic pole disposed to face the circumferential surface of the rotor;
A first thrust stator and a second thrust stator disposed opposite to each other across the shared magnetic pole,
The first thrust stator has a first thrust stator magnetic pole disposed to face one end face of the rotor,
The diskless thrust magnetic bearing according to claim 1, wherein the second thrust stator has a second thrust stator magnetic pole disposed so as not to face the other end face of the rotor. The first thrust stator has a first thrust winding;
The diskless thrust magnetic bearing according to claim 1, wherein the second thrust stator has a second thrust winding.   The diskless thrust magnetic bearing according to claim 2, wherein the second thrust winding has a larger number of turns than the first thrust winding.   4. The diskless thrust magnetic bearing according to claim 2, wherein the magnetic resistance of the magnetic circuit formed by the second thrust winding is larger than that of the magnetic circuit formed by the first thrust winding. .   5. The diskless thrust magnetic bearing according to claim 4, wherein the second thrust winding is larger in the radial direction than the first thrust winding.   6. The diskless thrust magnetic bearing according to claim 4, wherein the second thrust winding is larger in the axial direction than the first thrust winding.   7. The diskless thrust magnetic bearing according to claim 1, wherein a thickness of the second thrust stator magnetic pole is larger than a thickness of the first thrust stator magnetic pole. A rotor,
A radial stator disposed opposite to the circumferential surface of the rotor;
The first thrust stator and the second thrust stator of the diskless thrust magnetic bearing according to any one of claims 1 to 7, wherein the radial stator core of the radial stator is a common magnetic pole that is disposed to face each other with the radial stator interposed therebetween. A three-axis active control magnetic bearing comprising a thrust stator.

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