JP2019148269A - Magnetic bearing - Google Patents

Abstract

To provide a magnetic bearing capable of enlarging an electromagnetic force actuated between a rotor and a stator without causing enlargement of the stator and remarkable complication of shape and arrangement of each of a plurality of teeth possessed by the stator.SOLUTION: A stator main body includes: a specific connection part which connects teeth formed by winding each of at least two stator coils possessed by a stator coil group; and a boundary connection part which exists so as to be located between two stator coil groups adjoining to each other in a circumferential direction of a rotation axis and belongs to each of the two stator coil groups one by one and connects the teeth formed by winding each of two stator coils adjoining to each other in the circumferential direction of the rotation shaft. A length in a specific radial direction on the specific connection part is larger as compared to a length in a radial direction of the rotation shaft on the boundary connection part such that magnetic flux more than that on the boundary connection part passes therethrough.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetic bearing that rotatably supports a rotating shaft in a non-contact manner, and more particularly, to a radial magnetic bearing that can adjust the position of the rotating shaft in the radial direction.

  There is known a magnetic bearing that rotatably supports a rotating shaft of a rotating machine without contact. Magnetic bearings include radial magnetic bearings that suppress radial displacement of the rotating shaft.

  The radial magnetic bearing includes a rotor disposed on the rotation shaft and surrounding the rotation shaft, and a stator surrounding the rotor. The stator includes a stator body surrounding the rotor, a plurality of teeth extending from the stator body toward the rotor, and a plurality of coils wound around each of the plurality of teeth.

  In radial magnetic bearings, the rotor and the rotating shaft on which the rotor is installed can be rotated without contact by the electromagnetic force generated by energizing multiple coils acting on the rotor in the radial direction of the rotor. To support. When the rotating shaft is displaced in the radial direction, the rotating shaft is returned to the original position by adjusting the electromagnetic force acting on the rotor by changing the energization amount to a specific coil among the plurality of coils. It has become.

  In order to increase the electromagnetic force acting on the rotor, for example, it is conceivable to increase the number of turns of each of the plurality of coils. However, in order to increase the number of turns of each of the plurality of coils, the protrusion length of the teeth from the stator body (the length in the direction in which the teeth extend) and the interval between the two adjacent teeth in the circumferential direction of the rotor are increased. There is a need to. As a result, the stator becomes large, and the magnetic bearing becomes large.

  Therefore, in Patent Document 1 below, in order to secure a supporting force (that is, an electromagnetic force acting between the rotor and the stator) by the magnetic bearing while avoiding an increase in size of the magnetic bearing, the two adjacent in the circumferential direction. A magnetic bearing is disclosed that reduces leakage flux between two teeth. Specifically, in the magnetic bearing described in Patent Document 1, in order to reduce leakage magnetic flux between two teeth adjacent in the circumferential direction, the two teeth adjacent in the circumferential direction and the direction in which the magnetic flux flows. By narrowing the interval between two teeth that are in the same direction as each other, the interval between the two teeth constituting the magnetic loop (that is, the interval between two teeth in which the magnetic flux flows in opposite directions) is set to a plurality of teeth. Is wider than conventional magnetic bearings arranged at equal intervals in the circumferential direction. Moreover, in the magnetic bearing described in Patent Document 1, for each of the plurality of teeth, the radially outer width (the length in the circumferential direction) is larger than the radially inner width (the length in the circumferential direction). Leakage magnetic flux between the two adjacent teeth in the circumferential direction is further reduced by making the magnetic saturation difficult to occur on the radially outer side of the teeth so as to increase.

Japanese Patent No. 5700033

  However, in the magnetic bearing described in Patent Document 1, in order to increase the electromagnetic force generated between the rotor and the stator, a plurality of teeth are reduced in order to reduce the leakage magnetic flux between two adjacent teeth in the circumferential direction. Since a special shape and arrangement are adopted for each, the shape of the stator becomes complicated as compared with a conventional magnetic bearing in which a plurality of teeth are arranged at equal intervals in the circumferential direction.

  An object of the present invention includes a rotor disposed on a rotating shaft and surrounding the rotor, and a stator surrounding the rotor. The stator includes a stator body that surrounds the rotor, a plurality of teeth extending from the stator body toward the rotor, and a plurality of teeth. In a magnetic bearing including a plurality of coils wound around each of the rotor and the stator without increasing the size of the stator and significantly complicating the shape and arrangement of each of the teeth of the stator. It is an object of the present invention to provide a magnetic bearing capable of increasing the acting electromagnetic force.

  In order to achieve the above object, the inventors of the present application include a rotor that is disposed on a rotation shaft and surrounds the rotation shaft, and a stator that surrounds the rotor, and the stator surrounds the rotor and the stator body toward the rotor. In a magnetic bearing including a plurality of extending teeth and at least three stator coil groups each composed of a plurality of coils wound around each of the plurality of teeth, the magnetic bearing is caused by energization of each of the at least three stator coil groups. The study proceeded focusing on the flow of magnetic flux generated in the stator body. And the part which the magnetic flux which generate | occur | produces due to the electricity supply to a stator coil group flows among stator bodies, and the teeth which each of several stator coils which comprise the said stator coil group connect are connected If more magnetic flux can be passed to the connection part, the amount of magnetic flux flowing through the magnetic circuit formed so as to straddle the rotor and the stator due to energization of the stator coil group is increased overall. Therefore, it has been found that the electromagnetic force acting between the rotor and the stator can be increased without complicating the shape and arrangement of each of the plurality of teeth of the stator. In addition, the boundary connection portion that connects two specific connection portions adjacent to each other in the circumferential direction of the rotating shaft in the stator body does not contribute to the formation of the magnetic circuit. It has been found that the length of the stator can be shortened, thereby suppressing an increase in the size of the stator. The present invention has been completed based on such findings.

  Provided by the present invention is a magnetic bearing that rotatably supports a rotating shaft in a non-contact manner, the rotor being disposed on the rotating shaft, extending in a circumferential direction of the rotating shaft, and surrounding the rotating shaft; A stator extending in the circumferential direction of the rotating shaft and surrounding the rotor, the stator extending in the circumferential direction of the rotating shaft and surrounding the rotor, and the stator in the radial direction of the rotating shaft. A plurality of teeth that are formed so as to extend from the main body toward the rotor, are arranged at equal intervals in the circumferential direction of the rotation shaft, and are wound around each of the plurality of teeth. The plurality of stator coils are divided into at least three groups, each including at least three stator coil groups each having at least two stator coils. The stator body exists so as to correspond to each of the at least three stator coil groups, and each of the at least two stator coils included in each of the at least two stator coil groups is wound with teeth. Including at least three specific connection portions that connect, and at least three boundary connection portions that connect two specific connection portions adjacent to each other in the circumferential direction of the rotating shaft among the at least three specific connection portions, The first teeth and the rotor in which one of two stator coils adjacent to each other in the circumferential direction of the rotating shaft among the at least two stator coils is wound by magnetic flux generated due to energization of each of the stator coil groups. And at least two stator coils adjacent to each other in the circumferential direction of the rotating shaft. When the other coil is wound around and flows through the magnetic circuit formed across the rotor and the stator so as to pass through the second teeth paired with the first teeth and the specific connection portion in this order. An electromagnetic force is generated between the rotor and the stator, and the at least three stator coil groups are configured such that the electromagnetic force acts in each of at least three specific radial directions in the radial direction of the rotating shaft. Are arranged side by side in the circumferential direction of the rotating shaft, and the at least three specific radial directions are set to exist at equal intervals in the circumferential direction of the rotating shaft, and the specific connection portion The length in the specific radial direction is larger than the length in the radial direction in the boundary connection portion so that more magnetic flux passes through the boundary connection portion.

  In the magnetic bearing, at least 3 stator coils are provided such that electromagnetic force generated between the rotor and the stator due to energization of the stator coils acts on each of at least three specific radial directions. Since it is divided into two stator coil groups, electromagnetic force generated between the rotor and the stator due to energization of each of the plurality of stator coils and acting in the radial direction of the rotor is equally spaced in the circumferential direction of the rotor. Can be dispersed. As a result, the rotor and the rotation shaft provided with the rotor can be supported rotatably without contact.

  Here, the length in the specific radial direction in the specific connection portion of the stator body is the length in the radial direction in the boundary connection portion so that the magnetic flux flowing in the specific connection portion is larger than the magnetic flux flowing in the boundary connection portion. It is larger than Therefore, more magnetic flux can be flowed to the specific connection portion while shortening the length of the stator body in the direction in which the boundary connection portion exists. As a result, the amount of magnetic flux flowing through the magnetic circuit formed so as to straddle the rotor and the stator due to energization of each of the plurality of stator coils can be increased as a whole while suppressing an increase in the size of the stator body. Can do.

  That is, in the magnetic bearing, the electromagnetic force acting between the rotor and the stator is increased without enlarging the stator and significantly complicating the shape and arrangement of each of the plurality of teeth of the stator. Can do.

  In the magnetic bearing, preferably, the outer shape of the stator body is diagonally formed by two straight lines orthogonal to each other at the center of the rotating shaft when viewed from the axial direction of the rotating shaft. The first straight line and the second straight line have a same square length, and the at least three specific radial directions exist in opposite directions along one of the two straight lines. Four specific radial directions including a specific radial direction and third and fourth specific radial directions that exist in opposite directions along the other of the two straight lines, and the at least three stator coil groups Are arranged such that the electromagnetic force acts in the first specific radial direction, the first stator coil group arranged so that the electromagnetic force acts in the second specific radial direction, and the rotation And a second stator coil group located on the opposite side of the first stator coil group, and the electromagnetic force acting in the third specific radial direction, and the circumferential direction of the rotating shaft And the third stator coil group located between the first stator coil group and the second stator coil group, and the electromagnetic force is arranged to act in the fourth specific radial direction, The stator body includes four stator coil groups including a fourth stator coil group located on the opposite side of the third stator coil group with respect to the rotation shaft, and the stator body has the at least three specific connection portions. Four specific connection portions that exist so as to include each of the four corner portions, and the at least three boundary connection portions are two corners that are adjacent to each other in the circumferential direction of the rotation axis among the four corner portions. Part A four boundary connecting portion located between.

  In the above aspect, since the outer shape of the stator main body when viewed from the axial direction of the rotating shaft is square, the corner portion originally possessed by the stator main body due to the outer shape of the stator main body can be used for the specific connection portion. . For this reason, the specific connection portion can be made thicker than the boundary connection portion (the length in the radial direction can be increased) while being a simple shape of a square.

  In the above aspect, since the outer shape of the stator body is square when viewed from the axial direction of the rotation shaft, for example, when a plurality of rotation shafts arranged in parallel are rotatably supported, a plurality of stators are provided. It is possible to easily arrange the main bodies in a side-by-side arrangement.

  Here, in the magnetic bearing, preferably, each of the at least three stator coil groups includes two stator coils, and the specific connection portions and the boundary connection portions are alternately arranged in a circumferential direction of the rotating shaft. Yes.

  In the above aspect, since one specific connection portion is formed for one stator coil group, the length of the specific connection portion in the radial direction can be increased.

  In the magnetic bearing, each of the at least three stator coil groups includes at least three stator coils, and at least three teeth around which each of the at least three stator coils is wound include the at least three stator coils. Are used in common to the two magnetic circuits formed adjacent to each other in the circumferential direction of the rotating shaft due to energization of each of the two, and one of the two magnetic circuits functions as the first tooth. In addition, the other of the two magnetic circuits includes at least one common tooth that functions as the second tooth, and in the at least one common tooth, the directions of magnetic fluxes flowing through each of the two magnetic circuits are the same. Also good.

  In the above aspect, at least three stator coils constituting the stator coil group can be densely arranged. Therefore, the electromagnetic force generated between the rotor and the stator due to energization of the stator coil group can be further increased.

  In the magnetic bearing, preferably, the stator coils constituting each of the four stator coil groups are wound in a predetermined direction so as to generate a predetermined magnitude of electromagnetic force due to energization. A stator coil that includes a stator coil portion and constitutes the first stator coil group includes a stator that constitutes the first stator coil group when a current flows in the same direction as a current flows in the main stator coil portion. The second stator coil group further includes a first sub-stator coil portion wound in the same direction as the main stator coil portion so that an electromagnetic force generated due to energization of the coils is increased. The stator coil that performs current flows in a direction opposite to the direction in which current flows in the main stator coil portion. Therefore, the first sub-stator is wound while being wound in a direction opposite to the main stator coil portion so that an electromagnetic force generated due to energization to the stator coils constituting the second stator coil group is weakened. The stator coil further includes a second sub-stator coil portion connected in series with the coil portion, and the stator coil constituting the third stator coil group has a current in the same direction as the direction of current flow in the main stator coil portion. The third sub-stator that is wound in the same direction as the main stator coil portion so that the electromagnetic force generated due to energization of the stator coils constituting the third stator coil group is increased Each stator coil further including a coil portion and constituting the fourth stator coil group includes the main stator core The main stator so that the electromagnetic force generated due to the energization of the stator coils constituting the fourth stator coil group is weakened by the current flowing in the direction opposite to the direction in which the current flows in the coil portion. It further includes a fourth sub-stator coil portion that is wound in a direction opposite to the coil portion and connected in series to the third sub-stator coil portion.

  In the above aspect, the first sub-stator coil portion and the second sub-stator coil portion are connected in series, and the third sub-stator coil portion and the fourth sub-stator coil portion are connected in series. Therefore, it is caused by energizing the stator coils constituting the second stator coil group while increasing the electromagnetic force acting between the rotor and the stator due to energization of the stator coils constituting the first stator coil group. The electromagnetic force acting between the rotor and the stator can be reduced, and the electromagnetic force acting between the rotor and the stator due to the energization of the stator coils constituting the third stator coil group can be increased. The electromagnetic force acting between the rotor and the stator due to energization of the stator coils constituting the fourth stator coil group can be reduced.

  According to the magnetic bearing of the present invention, the electromagnetic force acting between the rotor and the stator is increased without enlarging the stator and significantly complicating the shape and arrangement of each of the plurality of teeth of the stator. be able to.

It is a top view which shows schematic structure of the magnetic bearing by embodiment of this invention. It is a top view which shows schematic structure of the magnetic bearing by the modification 1 of embodiment of this invention. It is a top view which shows schematic structure of the magnetic bearing by the modification 2 of embodiment of this invention. It is a top view which shows schematic structure of the magnetic bearing by the modification 3 of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  A magnetic bearing 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a plan view showing a schematic configuration of the magnetic bearing 10. In the following description, the axial direction, the radial direction, and the circumferential direction indicate the axial direction, the radial direction, and the circumferential direction of the rotating shaft 20, respectively.

  The magnetic bearing 10 is a radial magnetic bearing that suppresses radial displacement of the rotary shaft 20. The magnetic bearing 10 is a heteropolar magnetic bearing in which a magnetic circuit formed due to energization appears on a plane extending in a direction perpendicular to the axial direction of the rotary shaft 20.

  The magnetic bearing 10 supports the rotary shaft 20 so as to be rotatable without contact. The magnetic bearing 10 includes a rotor 22 provided on the rotary shaft 20 and a stator 30 disposed around the rotor 22. In the magnetic bearing 10, the rotor 22 is rotatably supported in a non-contact manner with respect to the stator 30 using an electromagnetic force acting between the rotor 22 and the stator 30, so that the rotating shaft 20 provided with the rotor 22 is supported. Is rotatably supported without contact.

  The rotor 22 is fixed to the rotating shaft 20 and rotates in the circumferential direction together with the rotating shaft 20. The rotor 22 is disposed on the rotating shaft 20 and extends in the circumferential direction so as to surround the rotating shaft 20. The rotor 22 has an annular shape having a cylindrical outer peripheral surface. The rotor 22 is externally fitted to the rotating shaft 20. The rotor 22 is disposed concentrically with the rotary shaft 20. The rotor 22 is made of a magnetic material. The rotor 22 is formed by, for example, laminating a plurality of electromagnetic steel plates in the axial direction.

  The stator 30 extends in the circumferential direction and is disposed so as to surround the rotor 22, and supports the rotor 22 so as to be rotatable in a non-contact manner by an electromagnetic force acting between the stator 22. The stator is made of a magnetic material. The stator 30 is formed by, for example, laminating a plurality of electromagnetic steel plates in the axial direction.

  Stator 30 includes a stator body 32, a plurality of teeth 34 formed to protrude from stator body 32, and a plurality of stator coils 35 wound around each of the plurality of teeth 34. Hereinafter, these will be described.

  The stator body 32 is formed in an annular shape surrounding the rotor 22 over the entire circumference. The details of the stator body 32 will be described later.

  A plurality (eight in the example shown in FIG. 1) of teeth 34 are arranged at equal intervals in the circumferential direction on the same circle. Each of the plurality of teeth 34 extends in the radial direction from the stator body 32 toward the rotor 22.

  A plurality (eight in the example shown in FIG. 1) of the stator coils 35 are wound around each of the plurality of teeth 34. A current flows through each of the plurality of stator coils 35 in order to generate an electromagnetic force that acts between the rotor 22 and the stator 30. When a current flows through each of the plurality of stator coils 35, a magnetic circuit is formed on a plane orthogonal to the axial direction. Specifically, the first tooth 341 in which the magnetic flux generated by energization of each of the two stator coils 35 adjacent in the circumferential direction is the tooth 34 around which one of the two stator coils 35 is wound. The rotor 22, the second tooth 342 that is the tooth 34 around which the other of the two stator coils 35 is wound, and the portion of the stator body 32 that connects the first tooth 341 and the second tooth 342 (described later) A magnetic circuit is formed so as to pass through the specific connection portion 32A) in this order. That is, the magnetic circuit is formed across the rotor 22 and the stator 30.

  The plurality of stator coils 35 are divided into at least three stator coil groups so that an electromagnetic force generated between the rotor 22 and the stator 30 due to energization acts on each of at least three specific radial directions. Yes. The at least three specific radial directions are set to exist at equal intervals in the circumferential direction.

  In the example shown in FIG. 1, the at least three specific radial directions include four specific radial directions DA, DB, DC, and DD. The four specific radial directions DA, DB, DC, and DD are directed in opposite directions along one of the two straight lines L1 and L2 (straight line L1) constituting the diagonal line of the stator body 32 when viewed from the axial direction. And third and fourth specific diameters that exist in opposite directions along the other of the two straight lines L1 and L2 (straight line L2). Including directions DB and DD. That is, the four specific radial directions DA, DB, DC, and DD are set to be arranged at intervals of 90 ° in the circumferential direction. The four specific radial directions DA, DB, DC, and DD all face the outside in the radial direction.

  The at least three specific radial directions include four specific radial directions DA, DB, DC, and DD, so that the at least three stator coil groups include four stator coil groups 35A, 35B, 35C, and 35D. The four stator coil groups 35A, 35B, 35C, and 35D include a first stator coil group 35A, a second stator coil group 35B, a third stator coil group 35C, and a fourth stator coil group 35D. Including.

  The first stator coil group 35A is composed of two stator coils 351, and is arranged such that electromagnetic force generated between the rotor 22 and the stator 30 due to energization acts in the first specific radial direction DA. ing. The two stator coils 351 constituting the first stator coil group 35A are arranged on both sides in the circumferential direction with respect to the straight line L1 extending in the first specific radial direction DA. The two stator coils 351 constituting the first stator coil group 35A are located outside the rotating shaft 20 in the first specific radial direction DA.

  The second stator coil group 35B includes two stator coils 352, and is arranged such that an electromagnetic force generated between the rotor 22 and the stator 30 due to energization acts in the second specific radial direction DB. ing. The second stator coil group 35B is disposed on the opposite side of the rotation shaft 22 from the first stator coil group 35A. The two stator coils 352 constituting the second stator coil group 35B are arranged on both sides in the circumferential direction with respect to the straight line L1 extending in the second specific radial direction DB. The two stator coils 352 constituting the second stator coil group 35B are located outside the rotating shaft 20 in the second specific radial direction DB.

  The third stator coil group 35C includes two stator coils 353, and is arranged such that an electromagnetic force generated between the rotor 22 and the stator 30 due to energization acts in the third specific radial direction DC. ing. The third stator coil group 35C is disposed between the first stator coil group 35A and the second stator coil group 35B in the circumferential direction. The two stator coils 353 constituting the third stator coil group 35C are arranged on both sides in the circumferential direction with respect to the straight line L2 extending in the third specific radial direction DC. The two stator coils 353 constituting the third stator coil group 35C are located outside the rotating shaft 20 in the third specific radial direction DC.

  The fourth stator coil group 35D is composed of two stator coils 354, and is arranged so that an electromagnetic force acting between the rotor 22 and the stator 30 due to energization acts in the fourth specific radial direction DD. ing. The fourth stator coil group 35D is arranged on the opposite side of the rotation shaft 22 from the third stator coil group 35C. The two stator coils 354 constituting the fourth stator coil group 35D are arranged on both sides in the circumferential direction with respect to the straight line L2 extending in the fourth specific radial direction DD. The two stator coils 354 constituting the fourth stator coil group 35D are located outside the rotating shaft 20 in the fourth specific radial direction DD.

  Stator coils 351, 352, 353, and 354 constituting each of the four stator coil groups 35A, 35B, 35C, and 35D include a main stator coil portion 36. The main stator coil portion 36 is wound around the teeth 34 in a predetermined direction so as to generate an electromagnetic force having a predetermined magnitude due to energization.

  Stator coil 351 constituting first stator coil group 35 </ b> A further includes a first sub-stator coil portion 381 in addition to main stator coil portion 36. The first sub-stator coil portion 381 is arranged such that current flows in the same direction as the direction of current flow in the main stator coil portion 36 included in the stator coil 351. Therefore, the electromagnetic force generated due to the energization of the main stator coil portion 36 and the electromagnetic force generated due to the energization of the first sub-stator coil portion 381 act in the same direction. As a result, the electromagnetic force generated due to energization of the stator coils 351 constituting the first stator coil group 35A is strengthened as a whole. When the electromagnetic force generated due to energization of the stator coil 351 constituting the first stator coil group 35A is weakened as a whole, the direction of the current flowing through the first sub-stator coil portion 381 is reversed. do it. That is, the first sub-stator coil portion 381 generates an electromagnetic force generated due to energization of the stator coil 351 constituting the first stator coil group 35A due to energization of the main stator coil portion 36. It arrange | positions so that it may increase / decrease on the basis of electromagnetic force.

  Stator coil 352 constituting second stator coil group 35 </ b> B further includes second sub-stator coil portion 382 in addition to main stator coil portion 36. The second sub-stator coil portion 382 is arranged such that current flows in a direction opposite to the direction in which current flows in the main stator coil portion 36 included in the stator coil 352. Therefore, the electromagnetic force generated due to the energization of the main stator coil portion 36 and the electromagnetic force generated due to the energization of the second sub-stator coil portion 382 act in opposite directions. As a result, the electromagnetic force generated due to energization of the stator coils 352 constituting the second stator coil group 35B is weakened as a whole. When the electromagnetic force generated due to energization of the stator coils 352 constituting the second stator coil group 35B is strengthened as a whole, the direction of the current flowing through the second sub-stator coil portion 382 is reversed. do it. In other words, the second sub-stator coil portion 382 generates an electromagnetic force generated due to energization of the stator coil 352 constituting the second stator coil group 35B due to energization of the main stator coil portion 36. It arrange | positions so that it may increase / decrease on the basis of electromagnetic force.

  Further, the second sub-stator coil portion 382 included in the stator coil 352 constituting the second stator coil group 35B is in contrast to the first sub-stator coil portion 381 included in the stator coil 351 constituting the first stator coil group 35A. Connected in series. Therefore, by energizing the second sub-stator coil portion 382, the first sub-stator coil portion 381 can also be energized. Note that the second sub-stator coil portion 382 is wound, for example, in a direction opposite to the first sub-stator coil portion 381, so that the direction of current flow is opposite to that of the first sub-stator coil portion 381. become.

  Stator coil 353 constituting third stator coil group 35 </ b> C further includes third sub-stator coil portion 383 in addition to main stator coil portion 36. The third sub-stator coil portion 383 is arranged so that a current flows in the same direction as the current flows in the main stator coil portion 36 of the stator coil 353. Therefore, the electromagnetic force generated due to the energization of the main stator coil portion 36 and the electromagnetic force generated due to the energization of the third sub-stator coil portion 383 act in the same direction. As a result, the electromagnetic force generated due to energization of the stator coil 353 constituting the third stator coil group 35C is strengthened as a whole. When the electromagnetic force generated due to energization of the stator coils 353 constituting the third stator coil group 35C is weakened as a whole, the direction of the current flowing through the third sub-stator coil portion 383 is reversed. do it. In other words, the third sub-stator coil portion 383 generates an electromagnetic force generated due to energization of the stator coil 353 constituting the third stator coil group 35C due to energization of the main stator coil portion 36. It arrange | positions so that it may increase / decrease on the basis of electromagnetic force.

  Stator coil 354 constituting fourth stator coil group 35 </ b> C further includes a fourth sub-stator coil portion 384 in addition to main stator coil portion 36. The fourth sub-stator coil portion 384 is arranged such that current flows in a direction opposite to the direction in which current flows in the main stator coil portion 36 included in the stator coil 354. Therefore, the electromagnetic force generated due to the energization of the main stator coil portion 36 and the electromagnetic force generated due to the energization of the fourth sub-stator coil portion 384 act in opposite directions. As a result, the electromagnetic force generated due to energization of the stator coil 354 constituting the fourth stator coil group 35D is weakened as a whole. In addition, when the electromagnetic force generated due to the energization of the stator coil 354 constituting the fourth stator coil group 35D is strengthened as a whole, the direction of the current flowing through the fourth sub-stator coil portion 384 is reversed. do it. That is, the fourth sub-stator coil portion 384 generates electromagnetic force generated due to energization of the stator coil 354 constituting the fourth stator coil group 35D due to energization of the main stator coil portion 36. It arrange | positions so that it may increase / decrease on the basis of electromagnetic force.

  Further, the fourth sub-stator coil portion 384 included in the stator coil 354 constituting the fourth stator coil group 35D is in contrast to the third sub-stator coil portion 383 included in the stator coil 353 constituting the third stator coil group 35C. Connected in series. Therefore, it is possible to energize the third sub stator coil portion 383 by energizing the fourth sub stator coil portion 384. Note that the fourth sub-stator coil portion 384 is wound in a direction opposite to the third sub-stator coil portion 383, for example, so that the direction of current flow is opposite to that of the third sub-stator coil portion 383. become.

  In the magnetic bearing 10, the electromagnetic force acting between the rotor 22 and the stator 30 without enlarging the size of the stator 30 and significantly complicating the shape and arrangement of each of the plurality of teeth 34 of the stator 30. The shape of the stator main body 32 has been devised so that it can be increased. Hereinafter, details of the stator body 32 will be described.

  In the example shown in FIG. 1, the outer shape of the stator body 32 is a square. That is, the stator main body 32 has four corners 32A, 32B, 32C, and 32D when viewed from the axial direction. Each of the four corners 32A, 32B, 32C, and 32D only needs to include a portion through which magnetic flux generated due to energization of each of the two stator coils 35 adjacent in the circumferential direction flows. In other words, each of the four corners 32A, 32B, 32C, and 32D has two side surfaces adjacent to each other in the circumferential direction among four side surfaces 321, 322, 323, and 324, which will be described later when viewed from the axial direction. It does not have to include the vertices that touch. The square diagonal line is constituted by two straight lines L1 and L2 that are orthogonal to each other at the center C1 of the rotating shaft 20 when viewed from the axial direction. The lengths of the two straight lines L1 and L2 are the same. When viewed from the axial direction, one of the two straight lines L1 and L2 (straight line L1) overlaps one end side with the corner portion 32A and the other end side with the corner portion 32C. When viewed from the axial direction, the other of the two straight lines L1 and L2 (straight line L2) overlaps one end side with the corner portion 32B and the other end side with the corner portion 32D. The stator body 32 has four side surfaces 321, 322, 323, and 324 when viewed from the axial direction. Of these four side surfaces 321, 322, 323, and 324, two side surfaces adjacent in the circumferential direction are orthogonal to each other when viewed from the axial direction.

  In the example shown in FIG. 1, the stator main body 32 includes four specific connection portions 32X and four boundary connection portions 32Y that are alternately arranged one by one in the circumferential direction. Hereinafter, these will be described.

  The four specific connection portions 32X exist so as to correspond to the four stator coil groups 35A, 35B, 35C, and 35D.

  The specific connection portion 32X existing corresponding to the stator coil group 35A includes a first tooth 341 which is a tooth 34 around which one of the two stator coils 351 of the stator coil group 35A is wound, and a first tooth 341 around which the other is wound. 2 teeth 342 are connected. The specific connection portion 32X existing corresponding to the stator coil group 35A includes a corner portion 32A.

  The specific connection portion 32X existing corresponding to the stator coil group 35B includes a first tooth 341 which is a tooth 34 around which one of the two stator coils 352 of the stator coil group 35B is wound, and a first tooth 341 around which the other is wound. 2 teeth 342 are connected. The specific connection portion 32X existing corresponding to the stator coil group 35B includes a corner portion 32B.

  The specific connection portion 32X existing corresponding to the stator coil group 35C includes a first tooth 341 that is a tooth 34 around which one of the two stator coils 353 of the stator coil group 35C is wound, and a first tooth 341 around which the other is wound. 2 teeth 342 are connected. The specific connection portion 32X existing corresponding to the stator coil group 35C includes a corner portion 32C.

  The specific connection portion 32X existing corresponding to the stator coil group 35D includes a first tooth 341 which is a tooth 34 around which one of two stator coils 354 included in the stator coil group 35D is wound, and a first tooth 341 around which the other is wound. 2 teeth 342 are connected. The specific connection portion 32X existing corresponding to the stator coil group 35D includes a corner portion 32D.

  That is, a magnetic flux generated due to energization flows through each of the four specific connection portions 32X. In other words, the four specific connections 32X each contribute to the formation of the magnetic circuit.

  Each of the four boundary connection portions 32Y connects two specific connection portions 32X adjacent in the circumferential direction among the four specific connection portions 32X.

  The boundary connection portion 32Y connecting the specific connection portion 32X existing corresponding to the stator coil group 35A and the specific connection portion 32X existing corresponding to the stator coil group 35B is transferred to the stator coil 351 belonging to the stator coil group 35A. It does not contribute to the formation of a magnetic circuit through which a magnetic flux generated due to energization flows, or a magnetic circuit through which a magnetic flux generated due to energization to the stator coil 352 belonging to the stator coil group 35B flows.

  The boundary connection portion 32Y connecting the specific connection portion 32X existing corresponding to the stator coil group 35B and the specific connection portion 32X existing corresponding to the stator coil group 35C is a stator coil 352 belonging to the stator coil group 35B. It does not contribute to the formation of a magnetic circuit through which a magnetic flux generated due to energization flows and a magnetic circuit through which a magnetic flux generated due to energization to the stator coil 353 belonging to the stator coil group 35C flows.

  The boundary connection portion 32Y connecting the specific connection portion 32X existing corresponding to the stator coil group 35C and the specific connection portion 32X existing corresponding to the stator coil group 35D is a stator coil 353 belonging to the stator coil group 35C. It does not contribute to the formation of a magnetic circuit through which a magnetic flux generated due to energization flows and a magnetic circuit through which a magnetic flux generated due to energization to the stator coil 354 belonging to the stator coil group 35D flows.

  The boundary connection portion 32Y connecting the specific connection portion 32X existing corresponding to the stator coil group 35D and the specific connection portion 32X existing corresponding to the stator coil group 35A is a stator coil 354 belonging to the stator coil group 35D. It does not contribute to the formation of a magnetic circuit through which magnetic flux generated due to energization flows, or a magnetic circuit through which magnetic flux generated due to energization of the stator coils 351 belonging to the stator coil group 35A flows.

  Here, in the example shown in FIG. 1, the length in the specific radial direction of the specific connection portion 32X is larger than the length in the radial direction of the boundary connection portion 32Y. In other words, the length in the radial direction of the specific connection portion 32X that contributes to the magnetic circuit through which the magnetic flux generated by energization flows is larger than the length in the radial direction of the boundary connection portion 32Y. . Therefore, the cross section seen from the circumferential direction of the specific connection portion 32X can be made larger than the cross section seen from the circumferential direction of the boundary connection portion 32Y. As a result, the specific connection portion 32X can pass more magnetic flux than the boundary connection portion 32Y. Therefore, the amount of magnetic flux flowing through the magnetic circuit formed across the rotor 22 and the stator 30 due to energization of each of the plurality of stator coils 35 can be increased as a whole.

  In the magnetic bearing 10, electromagnetic force generated between the rotor 22 and the stator 30 due to energization of the plurality of stator coils 35 acts on each of the four specific radial directions DA, DB, DC, DD. In addition, since the plurality of stator coils 35 are divided into four stator coil groups 35A, 35B, 35C, and 35D, they are generated between the rotor 22 and the stator 30 due to energization of each of the plurality of stator coils 34. In addition, the electromagnetic force acting in the radial direction can be dispersed at equal intervals in the circumferential direction. As a result, the rotor 22 and the rotary shaft 20 provided with the rotor 22 can be rotatably supported without contact.

  Here, the specific connection portion 32X of the stator body 32 has a length in the radial direction as compared with the boundary connection portion 32Y so that the magnetic flux flowing through the specific connection portion 32X is larger than the magnetic flux flowing through the boundary connection portion 32Y. Is getting bigger. Therefore, more magnetic flux can be passed through the specific connection portion 32X while shortening the length of the stator body 32 in the direction in which the boundary connection portion 32Y exists. As a result, the entire amount of magnetic flux flowing through the magnetic circuit formed so as to straddle the rotor 22 and the stator 30 due to energization of each of the plurality of stator coils 35 is suppressed while suppressing an increase in the size of the stator body 32. Can be increased.

  In other words, in the magnetic bearing 10, the electromagnetic force acting between the rotor 22 and the stator 30 without enlarging the size of the stator 30 and significantly complicating the shape and arrangement of each of the plurality of teeth 34 included in the stator 30. The power can be increased.

  Further, in the magnetic bearing 10, since the outer shape of the stator body 32 when viewed from the axial direction is a square, the corner portions 32A, 32B, 32C, 32D that the stator body 32 originally has due to the outer shape of the stator body 32 are provided. Can be used for the specific connection portion 32X. Therefore, the specific connection portion 32X can be made thicker (the length in the radial direction is larger) than the boundary connection portion 32Y while being a simple shape of a square.

  Further, in the magnetic bearing 10, since the outer shape of the stator body 32 is square when viewed from the axial direction, for example, when the plurality of rotating shafts 20 arranged in parallel are rotatably supported, a plurality of stators are provided. The main bodies 32 can be easily arranged in combination so as to be arranged side by side.

  In the magnetic bearing 10, since one specific connection portion 32X is formed for each of the four stator coil groups 35A, 35B, 35C, and 35D, the length of the specific connection portion 32X in the specific radial direction is set. It can be formed large.

[Modification of Embodiment]
In the above embodiment, each of the four stator coil groups 35A, 35B, 35C, and 35D is configured by the two stator coils 351, 352, 353, and 354. For example, like the magnetic bearing 10A shown in FIG. In addition, each of the four stator coil groups 35A, 35B, 35C, 35D may be constituted by three stator coils 351, 352, 353, 354. Alternatively, as in the magnetic bearing 10B shown in FIG. 3, each of the four stator coil groups 35A, 35B, 35C, and 35D may be configured by four stator coils 351, 352, 353, and 354.

  In the example shown in FIG. 2, the teeth 34 around which the stator coils 351, 352, 353, and 354 located in the middle in the circumferential direction in each of the four stator coil groups 34 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D are wound. , 352, 353, and 354, common teeth used in common for two magnetic circuits formed adjacent to each other in the circumferential direction. In the teeth 34, the directions of magnetic fluxes flowing through each of the two magnetic circuits are the same.

  In the example shown in FIG. 3, the teeth 34 around which the two stator coils 351, 352, 353, and 354 located in the middle in the circumferential direction in each of the four stator coil groups 34 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D are wound. The common teeth are commonly used for two magnetic circuits formed adjacent to each other in the circumferential direction due to energization of the stator coils 351, 352, 353, and 354. In the teeth 34, the directions of magnetic fluxes flowing through each of the two magnetic circuits are the same.

  In such magnetic bearings 10A, 10B, the four stator coils 351, 352, 353, 354 constituting the stator coil groups 35A, 35B, 35C, 35D can be densely arranged. Therefore, the electromagnetic force generated between the rotor 22 and the stator 30 due to energization of the stator coil groups 35A, 35B, 35C, and 35D can be further increased.

[Other Modifications of Embodiment]
In the above embodiment, the outer shape of the stator body 32 when viewed from the axial direction is square, but the outer shape of the stator body 32 when viewed from the axial direction, such as the magnetic bearing 10C shown in FIG. May be octagonal. In addition, as the outer shape of the stator main body 32, it is also possible to employ a square corner portion with an R-shaped chamfer.

  As mentioned above, although embodiment of this invention was explained in full detail, these are illustrations to the last, Comprising: This invention is not interpreted restrictively at all by description of the above-mentioned embodiment.

  For example, in the above embodiment, four specific radial directions DA, DB, DC, and DD are set, but three specific radial directions set at intervals of 120 ° in the circumferential direction may be adopted.

  For example, in the above-described embodiment, the basic magnetic circuit is formed by energizing the main stator coil portion 36. However, the basic magnetic circuit may be formed using a permanent magnet, for example. In this case, since the main stator coil portion 36 is not necessary, the copper loss can be reduced accordingly.

  For example, in the above-described embodiment, the position of the rotating shaft 20 (rotor 22) may be adjusted only by changing the energization amount of any of the four stator coil groups 35A, 35B, 35C, and 35D.

DESCRIPTION OF SYMBOLS 10 Magnetic bearing 22 Rotor 30 Stator 32 Stator main body 32X Specific connection part 32Y Boundary connection part 34 Teeth 341 1st teeth 342 2nd teeth 35 Stator coil 35A Stator coil group 35B Stator coil group 35C Stator coil group 35D Stator coil group 351 Stator coil group 352 Stator coil 353 Stator coil 354 Stator coil 36 Main stator coil portion 381 First sub stator coil portion 382 Second sub stator coil portion 383 Third sub stator coil portion 384 Fourth sub stator coil portion

Claims (5)

A magnetic bearing that rotatably supports the rotating shaft without contact;
A rotor disposed on the rotating shaft, extending in a circumferential direction of the rotating shaft and surrounding the rotating shaft;
A stator extending in the circumferential direction of the rotating shaft and surrounding the rotor,
The stator is
A stator body extending in the circumferential direction of the rotating shaft and surrounding the rotor;
A plurality of teeth that are formed so as to extend from the stator body toward the rotor in the radial direction of the rotating shaft, and are arranged at equal intervals in the circumferential direction of the rotating shaft and located on the same circle; ,
A plurality of stator coils wound around each of the plurality of teeth is divided into at least three groups, each including at least three stator coil groups each having at least two stator coils;
The stator body is
At least three identifications that connect the teeth wound around each of the at least two stator coils that exist in each of the at least three stator coil groups and that each of the at least three stator coil groups has. A connecting part,
Including at least three boundary connection portions that connect two specific connection portions adjacent in the circumferential direction of the rotating shaft among the at least three specific connection portions;
A magnetic flux generated due to energization of each of the at least three stator coil groups is wound around one of two stator coils adjacent to each other in the circumferential direction of the rotating shaft among the at least two stator coils. Of the at least two stator coils of the teeth, the rotor, and the at least two stator coils, the other one of the two stator coils adjacent in the circumferential direction of the rotating shaft is wound, and the second tooth and the specific connection portion paired with the first tooth By flowing through a magnetic circuit formed across the rotor and the stator so as to pass in this order, an electromagnetic force is generated between the rotor and the stator,
The at least three stator coil groups are arranged side by side in the circumferential direction of the rotary shaft so that the electromagnetic force acts on each of at least three specific radial directions in the radial direction of the rotary shaft,
The at least three specific radial directions are set to exist at equal intervals in the circumferential direction of the rotating shaft,
The length of the specific connection portion in the specific radial direction is larger than the length of the boundary connection portion in the radial direction so that more magnetic flux passes through the boundary connection portion. The magnetic bearing according to claim 1,
The outer shape of the stator body is configured by a diagonal line formed by two straight lines orthogonal to each other at the center of the rotating shaft when viewed from the axial direction of the rotating shaft, and the two straight lines have the same length. Has a square that is
The at least three specific radial directions are first and second specific radial directions that exist in opposite directions along one of the two straight lines, and opposite directions along the other of the two straight lines. Four specific radial directions including the third and fourth specific radial directions present so as to face
The at least three stator coil groups are arranged such that the electromagnetic force acts in the first specific radial direction, and the electromagnetic force acts in the second specific radial direction. The second stator coil group positioned on the opposite side of the first stator coil group with respect to the rotating shaft, and the electromagnetic force acting in the third specific radial direction. A third stator coil group positioned between the first stator coil group and the second stator coil group in the circumferential direction of the rotating shaft, and the electromagnetic force is in the fourth specific radial direction. Four stator coil groups including a fourth stator coil group that is arranged to act and is located on the opposite side of the third stator coil group with respect to the rotation axis;
The at least three specific connection portions are four specific connection portions that exist so as to include each of the four corners of the stator body,
The magnetic bearing, wherein the at least three boundary connection portions are each four boundary connection portions located between two corner portions adjacent to each other in the circumferential direction of the rotating shaft among the four corner portions. The magnetic bearing according to claim 1 or 2,
Each of the at least three stator coil groups comprises two stator coils;
The magnetic bearing in which the specific connection portion and the boundary connection portion are alternately arranged in the circumferential direction of the rotating shaft. The magnetic bearing according to claim 1 or 2,
Each of the at least three stator coil groups comprises at least three stator coils;
The at least three teeth around which each of the at least three stator coils is wound are formed to be adjacent to each other in the circumferential direction of the rotating shaft due to energization of each of the at least three stator coils. Including at least one common tooth that is used in common for a magnetic circuit, functions as the first tooth on one of the two magnetic circuits and functions as the second tooth on the other of the two magnetic circuits,
In the at least one common tooth, the directions of magnetic fluxes flowing through each of the two magnetic circuits are the same as each other. The magnetic bearing according to any one of claims 2 to 4,
The stator coils constituting each of the four stator coil groups are
Including a main stator coil portion wound in a predetermined direction so as to generate a predetermined magnitude of electromagnetic force due to energization,
The stator coils constituting the first stator coil group are:
The main stator coil portion is configured so that an electromagnetic force generated due to energization of the stator coils constituting the first stator coil group is strengthened by the current flowing in the same direction as the direction of current flow. A first sub-stator coil portion wound in the same direction as the stator coil portion;
The stator coil constituting the second stator coil group is:
The electromagnetic force generated due to energization of the stator coils constituting the second stator coil group is weakened by the current flowing in the direction opposite to the direction in which the current flows in the main stator coil portion. A second sub-stator coil portion wound in a direction opposite to the main stator coil portion and connected in series to the first sub-stator coil portion;
The stator coil constituting the third stator coil group is
The main stator coil portion is configured so that an electromagnetic force generated due to energization of the stator coils constituting the third stator coil group is strengthened by the current flowing in the same direction as the direction of current flow. A third sub-stator coil portion wound in the same direction as the stator coil portion;
Each stator coil constituting the fourth stator coil group is
The electromagnetic force generated due to energization of the stator coils constituting the fourth stator coil group is weakened by the current flowing in the direction opposite to the direction in which the current flows in the main stator coil portion. The magnetic bearing further includes a fourth sub-stator coil portion wound in a direction opposite to the main stator coil portion and connected in series to the third sub-stator coil portion.

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