JP2017143663A - Embedded magnet type rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-efficiency embedded magnet type rotary machine.SOLUTION: An embedded magnet type rotary machine 100 comprises a stator 1, a rotor 2 and an end face fixed magnet 3. The rotor 2 is rotated along a surface of the stator 1 and includes embedded magnets that are permanent magnets disposed inside of a face opposing the stator 1. The end face fixed magnet 3 is a permanent magnet that is fixed on one end face of the rotor 2 in an axial direction. The end face fixed magnet 3 includes magnetic poles 31A-31H disposed on an opposite face 32 that is a face opposing one end face of the rotor 2 in the axial direction. The magnetic poles 31A-31H are positioned in a counter-clock-wise direction in a circumferential direction of the end face fixed magnet. A magnetic flux flows from one end face side of the rotor 2 in the axial direction into the magnetic poles 31A, 31C, 31E and 31G. In the magnetic poles 31B, 31D, 31F and 31H, a magnetic flux flows out towards one end face side of the rotor 2 in the axial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an embedded magnet type rotating machine.

  The embedded magnet type rotating machine is also called an IPM (Interior Permanent Magnet) motor, and has a rotor in which a permanent magnet is embedded. Since the embedded magnet type rotating machine rotates using not only the magnet torque but also the reluctance torque, it can be driven with high output and high efficiency.

  Further, since the permanent magnet is embedded in the rotor, the permanent magnet does not jump out of the rotor due to the centrifugal force generated by the rotation of the rotor. Therefore, the embedded magnet type rotating machine is excellent in mechanical safety.

  Patent Document 1 discloses an embedded magnet type electric motor having a 6-pole V-shaped magnet. This embedded magnet type electric motor is of an inner rotor type and includes a stator and a rotor.

  The rotor includes a first rotor core. Two permanent magnets (first permanent magnets) arranged in a substantially V shape when viewed from the axial direction are embedded in the first rotor core. The two first permanent magnets are arranged so that the same magnetic pole faces each other. Further, the second permanent magnet is disposed on the end face in the axial direction of the first rotor core. The second permanent magnet is arranged in the axial direction so that the same magnetic pole as that of the first permanent magnet is located on the surface on the first rotor core side in the axial direction of the second permanent magnet. A rotor yoke made of a magnetic material is disposed in contact with the second permanent magnet on the surface opposite to the surface on the first rotor core side in the axial direction of the second permanent magnet.

  The magnetic flux flowing in the first rotor core can be increased by flowing the magnetic flux of the second permanent magnet into the inside of the V shape formed by the two first permanent magnets. Thereby, the interior magnet type electric motor concerning patent documents 1 has realized size reduction, high output, and high efficiency.

Japanese Patent No. 4655646

  In an embedded magnet type electric motor, reluctance torque is generated due to the difference in inductance between a d-axis magnetic path where magnetic flux does not easily flow and a q-axis magnetic path where magnetic flux easily flows. The inductance is proportional to the permeance of the magnetic path (the reciprocal of the magnetic resistance), and the reluctance torque increases as the difference in inductance between the d-axis magnetic path and the q-axis magnetic path increases. In the interior magnet type electric motor according to Patent Document 1 as described above, since the rotor yoke is disposed in contact with the second permanent magnet, the magnetic flux generated by the stator coil is a magnet formed in the first rotor. In addition to the circuit, a magnetic circuit passing through the rotor yoke is also formed. That is, by forming a parallel magnetic circuit (rotor yoke) in a magnetic circuit with a small permeance (d-axis magnetic path in the rotor), the permeance of the entire magnetic circuit increases. As a result, an increase in the d-axis magnetic path (d-axis inductance) reduces the difference between the d-axis inductance and the q-axis inductance, thereby reducing the reluctance torque. Therefore, the magnetic flux generated in the stator coil cannot be used effectively, which has been a factor of reducing the efficiency of the embedded magnet type electric motor.

  Further, when the rotating machine is configured without providing the rotor yoke, the decrease in the reluctance torque as described above can be suppressed, but the magnetic circuit is opened as viewed from the second permanent magnet, so that the rotor end portion Permeance is reduced, and the operating point of the second permanent magnet is lowered. As a result, the magnetic flux (magnet torque) of the permanent magnet that contributes to the torque is reduced, which is a factor of reducing the efficiency of the embedded magnet type electric motor.

  An object of the present invention is to provide a highly efficient embedded magnet type rotating machine.

  The present invention is an embedded magnet type rotating machine, and is provided on a stator, a rotor provided coaxially with the stator, and fixed to at least one end face in the axial direction of the rotor and the rotor. An end face fixed magnet, and the end face fixed magnet includes a first magnetic pole disposed on a facing surface that is a surface facing one end surface, and a second magnetic pole disposed adjacent to the first magnetic pole on the facing surface. And forming a magnetic flux from the first magnetic pole toward the second magnetic pole.

  In the above case, since a magnetic flux from the first magnetic pole to the second magnetic pole is formed in the end face fixed magnet, a desired magnetic flux can be formed without providing a rotor yoke. Accordingly, the operating point of the permanent magnet is not lowered, and as a result, the reduction of the magnet torque is also suppressed. Furthermore, an increase in inductance in the d-axis direction is also suppressed, and a decrease in reluctance torque can be prevented.

  Moreover, the end surface fixed magnet may be composed of a polar anisotropic magnet.

  In this case, since the magnetic flux flow in the axial direction and radial direction can be configured by a single polar anisotropic magnet, it is effective in reducing the number of parts and reducing the cost compared to the case where the same action is performed using a plurality of flat magnets. It is.

  The end face fixed magnet constitutes a first magnetic pole, constitutes a first permanent magnet magnetized in a direction from the opposing surface toward the opposite surface to the opposing surface, and constitutes a second magnetic pole, from the opposite surface. A second permanent magnet that is magnetized in a direction toward the facing surface; and a third permanent magnet that forms a magnetic flux and is magnetized in a direction from the first permanent magnet toward the second permanent magnet. The magnet, the second permanent magnet, and the third permanent magnet may be arranged in a Halbach array.

  By arranging the first permanent magnet, the second permanent magnet, and the third permanent magnet in a Halbach array to form the end face fixed magnet, the cost of the end face fixed magnet can be reduced. Note that the number of divisions of the Halbach array may be four or more. In this case, not only the first permanent magnet, the second permanent magnet, and the third permanent magnet but also other permanent magnets are used in the Halbach array.

  The interior magnet type rotating machine according to the present invention can be driven with high efficiency.

1 is a perspective view of an interior magnet type rotating machine according to an embodiment of the present invention. It is a perspective view of the rotor and end surface fixed magnet which are shown in FIG. It is the front view which looked at the rotor shown in FIG. 2 from the axial direction. It is a front view of an end surface fixed magnet when the end surface fixed magnet shown in FIG. 2 is viewed in the axial direction from the rotor side. It is a figure which shows the direction of the magnetic flux of an end surface fixed magnet when the end surface fixed magnet shown in FIG. 2 is seen to an axial direction from the rotor side. It is a figure which shows the magnetization direction in the cross section of the end surface fixed magnet shown in FIG. FIG. 4 is an enlarged view of a vicinity region of a magnet arrangement portion in the rotor shown in FIG. It is a figure which shows typically the flow of the magnetic flux of the end surface fixed magnet shown in FIG. It is a figure which shows typically the flow in the rotor of the magnetic flux which generate | occur | produces in the stator shown in FIG. It is a figure which shows the other example of the polar anisotropic magnet which comprises the end surface fixed magnet shown in FIG. It is a figure which shows the direction of the magnetic flux in the cross section of the polar anisotropic magnet shown to FIG. 10A. It is a figure which shows an example of the arrangement | sequence in the case of comprising the end surface fixed magnet shown in FIG. 2 by arranging a plurality of permanent magnets. FIG. 3 is a perspective view of an end face fixing magnet when a holding member is attached to the end face fixing magnet shown in FIG. 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

{Configuration of embedded magnet type rotating machine 100}
FIG. 1 is a perspective view of an embedded magnet type rotating machine 100 according to the present embodiment. As shown in FIG. 1, the embedded magnet type rotating machine 100 includes a stator 1, a rotor 2, an end surface fixed magnet 3, and a rotating shaft 9. The embedded magnet type rotating machine 100 is an inner rotor type in which the rotor 2 rotates on the inner peripheral side of the stator 1. In FIG. 1, only one end face fixed magnet 3 on one end face side of the rotor 2 is shown, but the embedded magnet type rotating machine 100 includes two end face fixed magnets 3. Details of the end face fixed magnet 3 will be described later.

  The stator 1 includes a stator yoke 11, a plurality of teeth 12, and a plurality of coils 13. In FIG. 1, the reference signs for some teeth 12 and some coils 13 are omitted. The stator yoke 11 and the teeth 12 are formed of, for example, an electromagnetic steel plate, a dust material, an amorphous magnetic material, or the like.

  The stator yoke 11 has a hollow cylindrical shape extending in the direction of the rotating shaft 9. The teeth 12 extend from the inner peripheral surface of the stator yoke 11 toward the rotary shaft 9. By winding the coil 13 around the tooth 12, the coil 13 is disposed in a space (slot) formed between the teeth 12. Hereinafter, the extending direction of the rotating shaft 9 is referred to as “axial direction”, the direction perpendicular to the axial direction is referred to as “radial direction”, and the circumferential direction of a circle centered on the rotation center of the rotating shaft 9 is referred to as “circumferential direction”.

  FIG. 2 is a perspective view of the rotor 2 and the end surface fixed magnet 3 shown in FIG. As shown in FIG. 2, the rotation axis α is the central axis of the rotation shaft 9. The rotor 2 includes a rotor core 21 and magnet arrangement portions 22A to 22H. The rotor core 21 has a cylindrical shape extending in the axial direction. As with the stator yoke 11, the rotor core 21 is formed of an electromagnetic steel plate, a dust material, an amorphous magnetic material, or the like. The rotor core 21 is arranged so that the outer peripheral surface faces the inner peripheral surface of the stator 1 and can rotate about the rotation axis α. A gap of a predetermined distance is formed between the rotor core 21 and the tip of the tooth 12.

  In each of the magnet arrangement portions 22 </ b> A to 22 </ b> H, two permanent magnets are embedded in the rotor core 21. The two permanent magnets are arranged in the rotor core 21 so as to be V-shaped when viewed from the axial direction. The rotor 2 rotates with magnet torque and reluctance torque generated by a magnetic field generated in the stator 1 by energizing the coil 13 and a magnetic field of a permanent magnet embedded in the rotor 2. Details of the magnet arrangement portions 22A to 22H will be described later.

  As described above, the embedded magnet type rotating machine 100 includes the two end face fixed magnets 3. The two end face fixed magnets 3 are annular polar anisotropic magnets, and are respectively fixed to end faces in the axial direction of the rotor core 21. For example, the end surface fixing magnet 3 is fixed to the end surface in the axial direction of the rotor 2 by an adhesive or the like. The end surface fixed magnet 3 is magnetized in the circumferential direction and the axial direction. The end surface fixed magnet 3 has a plurality of surfaces in the axial direction, and a surface facing the rotor core 21 is referred to as a facing surface 32, does not face the rotor core 21, and is opposite to the facing surface 32 in the axial direction. The surface located at is called the exposed surface 35. The arrangement of the magnetic poles in the end face fixed magnet 3 will be described later.

{Structure of rotor 2}
FIG. 3 is a front view of the rotor 2 shown in FIG. 2 as viewed from the axial direction. As shown in FIG. 3, magnet placement portions 22 </ b> A to 22 </ b> H are formed on the rotor 2 along the circumferential direction. The magnet arrangement part 22A is arranged above FIG. 3, and the magnet arrangement parts 22B to 22H are arranged in the counterclockwise order from the magnet arrangement part 22A.

  Magnet arrangement | positioning parts 22A-22H have the same structure except the direction of the magnetic pole in the two permanent magnets arrange | positioned at each. For this reason, the magnet arrangement part 22A is taken as an example to describe the structure of the magnet arrangement part, and then the direction of the magnetic poles of the permanent magnets arranged in each of the magnet arrangement parts 22A to 22H is described.

  In the rotor 2 shown in FIG. 3, two magnet insertion spaces 23 that penetrate the rotor core 21 in the axial direction are formed in the magnet arrangement portion 22 </ b> A. The two magnet insertion spaces 23 and the cross-sectional shape thereof are formed at positions that are line symmetric with respect to a straight line L1 that passes through the rotation axis α and extends in the radial direction. That is, the two magnet insertion spaces 23 are formed in a V shape when viewed from the axial direction of the rotor 2.

  In FIG. 3, the block arrow shown with a broken line shows the magnetization direction of the permanent magnet arrange | positioned in each of magnet arrangement | positioning part 22A-22H. In the magnet arrangement portion 22 </ b> A, the two permanent magnets 24 </ b> A are arranged such that the N pole faces the outer peripheral surface of the rotor core 21. Similarly, in each of the magnet arrangement portions 22C, 22E, and 22G, the two permanent magnets 24C, the two permanent magnets 24E, and the two permanent magnets 24G have their north poles facing the outer peripheral surface of the rotor core 21, respectively. Placed in. On the other hand, in each of the magnet arrangement portions 22B, 22D, 22F, and 22H, the two permanent magnets 24B, the two permanent magnets 24D, the two permanent magnets 24F, and the two permanent magnets 24H each have an S pole that is a rotor core. It arrange | positions so that the outer peripheral surface of 21 may be faced.

{Structure of end face fixed magnet 3}
FIG. 4 is a diagram illustrating the facing surface 32 of the end surface fixed magnet 3 when the end surface fixed magnet 3 illustrated in FIG. 2 is viewed from the axial direction of the rotor 2. As shown in FIG. 4, the end surface fixed magnet 3 has magnetic poles 31 </ b> A to 31 </ b> H, and the magnetic poles 31 </ b> A to 31 </ b> H are located on the facing surface 32. In FIG. 4, broken line areas indicating the magnetic poles 31 </ b> A to 31 </ b> H indicate a rough range of the magnetic poles 31 </ b> A to 31 </ b> H, and do not indicate that the magnetic pole is limited to the broken line area.

  An example of magnetic pole arrangement is given below. When the magnetic poles 31A, 31C, 31E, and 31G are N poles, the magnetic poles 31B, 31D, 31F, and 31H are S poles, and the magnetic poles are alternately arranged along the circumferential direction. Further, the arrangement of the N pole and S pole is not limited to the above.

  FIG. 5 is a diagram showing the direction of the magnetic flux in the end surface fixed magnet 3 when the end surface fixed magnet 3 is viewed in the axial direction from the rotor core 21 when the magnetic poles are arranged in FIG. 4. As shown in FIG. 5, the end face fixed magnet 3 is magnetized in the circumferential direction from the magnetic pole 31B toward each of the magnetic poles 31A and 31C. Similarly, the end face fixed magnet 3 is magnetized from the magnetic pole 31D toward each of the magnetic poles 31C and 31E, magnetized from the magnetic pole 31F toward each of the magnetic pole 31E and the magnetic pole 31G, and from the magnetic pole 31H to the magnetic pole 31G and the magnetic pole 31A. It is magnetized toward each of these. That is, in the end face fixed magnet 3, a magnetic flux 33 is formed from the south pole to the north pole formed on the facing face 32. The magnetic flux 33 described here refers to the “direction of the magnetic flux” and does not represent the magnetic flux itself, but is schematically represented as a magnetic flux.

  FIG. 6 is a view showing an AA cross section of the end surface fixed magnet 3 shown in FIG. 4. As shown in FIG. 6, the magnetic flux 33 changes from the S pole formed along the facing surface 32 toward the N pole while changing the direction with respect to the rotation axis α direction. That is, the magnetic flux 33 forms a U-shaped path in the end surface fixed magnet 3 with the opposing surface 32 in the end surface fixed magnet 3 as a starting point and an end point.

  As described above, in the end face fixed magnet 3, the magnetic poles 31 </ b> A to 31 </ b> H are formed on the facing surface 32 side, so that magnetic flux is formed between the magnetic poles 31 </ b> A to 31 </ b> H and the rotor core 21. On the other hand, since no magnetic pole is formed on the exposed surface 35 side, no magnetic flux is formed between the rotor core 21 and the exposed surface 35.

  The end surface fixed magnet 3 is manufactured as follows, for example. First, as shown in FIG. 4, a process of manufacturing an annular polar anisotropic magnet that forms a magnetic flux along the circumferential direction will be described. Specifically, a magnetic powder is filled in a die of an annular polar anisotropic magnet, and a coil is arranged on the outer peripheral side surface of the die. The coil is disposed at a position corresponding to the magnetic poles 31A to 31H. Thereafter, a pulse current is applied to the coil to generate a magnetic field. The direction of the pulse current flowing through the coil is changed according to the positions of the magnetic poles 31A to 31H. Thereby, an annular polar anisotropic magnet in which the direction of the magnetic field is oriented along the circumferential direction is manufactured. At this time, the magnetic poles 31A to 31H are not formed on one end surface (corresponding to the facing surface 35) on the axial direction side of the annular polar anisotropic magnet.

  Next, a process for forming the magnetic poles 31A to 31H will be described. A coil is disposed above the end face in the axial direction of the polar anisotropic magnet manufactured as described above. The coil is disposed at a position corresponding to the magnetic poles 31A to 31H. A pulse current is applied to the arranged coil. The direction of the pulse current flowing through the coil is changed according to the positions of the magnetic poles 31A to 31H. Thereby, the end surface fixed magnet 3 provided with the magnetic poles 31A to 31H is manufactured.

  However, you may manufacture the end surface fixed magnet 3 by methods other than the manufacturing method mentioned above. That is, if the end face fixing magnet 3 having the magnetic flux 33 as shown in FIGS. 5 and 6, the magnetic poles 31 </ b> A to 31 </ b> H are formed on the facing surface 32, and no magnetic pole is formed on the exposed surface 35 can be manufactured. The manufacturing method of the magnet 3 is not specifically limited.

{Positional relationship between rotor 2 and end face fixed magnet 3}
FIG. 7 is an enlarged view of the rotor 2 shown in FIG. 3 in the region R1. As shown in FIG. 7, the positional relationship between the magnet placement portion 22A in the rotor 2 shown in FIG. 3 and the magnetic pole 31A of the end surface fixed magnet 3 shown in FIG. 4 will be described.

  As described above, the two permanent magnets 24A are respectively inserted into the two magnet insertion spaces 23 formed in the magnet arrangement portion 22A. The two permanent magnets 24 </ b> A are inserted so that the N pole faces the outer peripheral surface of the rotor core 21. The arrows shown in FIG. 7 indicate the magnetization directions of the two permanent magnets 24A.

  The end surface fixed magnet 3 is fixed so that the facing surface 32 of the end surface fixed magnet 3 contacts one end surface in the axial direction of the rotor core 21. When the rotor 2 is viewed from the axial direction, the magnetic pole 31A formed on the facing surface 32 is arranged so as to be positioned between the two permanent magnets 24A in the magnet arrangement portion 22A. Further, since the magnetic poles 31B to 31H of the end face fixed magnet 3 are similarly arranged, each magnetic pole of the end face fixed magnet 3 positioned between the two permanent magnets faces the outer peripheral surface of the rotor core 21 in the magnet arrangement portion. It matches the magnetic pole.

{Generation of magnet torque}
Hereinafter, the magnet torque will be described with reference to FIG.

  FIG. 8 is a diagram schematically showing the flow of magnetic flux in the embedded magnet type rotating machine 100. In FIG. 8, only one end face 21 </ b> A of the rotor 2 in the axial direction is shown in order to easily show the path of the magnetic flux of the end face fixed magnet 3. Moreover, in FIG. 8, the display of the code | symbol with respect to a one part magnet arrangement | positioning part and a permanent magnet is abbreviate | omitted. Hereinafter, the path of the magnetic flux from the magnetic pole 31A of the end face fixed magnet 3 to the end face fixed magnet 3 via the stator 1 and the rotor 2 will be described with reference to FIG.

  A part of the magnetic flux 51 flows from the magnetic pole 31 </ b> A toward a region between the two permanent magnets 24 </ b> A in the magnet arrangement portion 22 </ b> A of the rotor 2. The magnetic flux 51 described here and the magnetic fluxes 52 to 55 described later indicate the “direction of the magnetic flux” and, like the magnetic flux 33, are schematically expressed as magnetic fluxes.

  In the magnet arrangement part 22 </ b> A, the N poles of the two permanent magnets 24 </ b> A are arranged so as to face the outer peripheral surface of the rotor core 21. For this reason, the magnetic flux 51 flows toward the stator 1 from the region between the two permanent magnets 24A. Hereinafter, the magnetic flux 51 flowing toward the stator 1 is referred to as a magnetic flux 52. The magnetic flux 52 flows through the air gap between the stator 1 and the rotor 2 and flows toward the teeth 12 of the stator 1. Thereafter, the magnetic flux 52 passes from the tooth 12 through the stator yoke 11 and the other teeth 12, through the air gap between the stator 1 and the rotor 2, and again toward the rotor 2. A part of the magnetic flux 52 heading again toward the rotor 2 flows in a region between the two permanent magnets 24B in the magnet arrangement portion 22B. Hereinafter, the magnetic flux 52 that flows from the stator 1 to the region between the two permanent magnets 24 </ b> B is referred to as a magnetic flux 53.

  The magnetic flux 53 flows from the region between the two permanent magnets 24B toward the magnetic pole 31B. That is, a part of the magnetic flux 51 forms a magnetic flux that flows to the magnetic pole 31B via the magnetic pole 31A, the magnet arrangement portion 22A, the stator 1, and the magnet arrangement portion 22B. Similarly, part of the magnetic flux generated from the magnetic poles 31C, 31E, and 31G of the end face fixed magnet passes through the magnet arrangement portions 22C, 22E, and 22G, respectively. And these magnetic flux forms the magnetic flux which flows into the end surface fixed magnet 3 via the stator 1 and any one of magnet arrangement | positioning part 22B, 22D, 22F, and 22H.

{Generation of reluctance torque}
Hereinafter, generation of reluctance torque in the interior magnet type rotating machine 100 will be described with reference to FIG. Then, the mechanism which suppresses the reduction | decrease in a reluctance torque by the embedded magnet type rotary machine 100 being provided with the end surface fixed magnet 3 is demonstrated.

  FIG. 9 is a diagram schematically showing the flow of the magnetic flux generated by the coil 13 shown in FIG. 1 in the rotor 2. Hereinafter, the magnetic flux generated by the coil 13 is referred to as magnetic flux generated in the stator 1. FIG. 9 corresponds to a front view of the rotor 2 viewed from the axial direction, as in FIG. Moreover, in FIG. 9, the display of the code | symbol of magnet arrangement | positioning parts 22A-22H and the magnet insertion space 23 is abbreviate | omitted.

  In FIG. 9, a magnetic flux 61 is a magnetic flux flowing in the q-axis direction of the rotor 2 among magnetic fluxes generated in the stator 1, and a magnetic flux 62 is a magnetic flux flowing in the d-axis direction of the rotor 2.

  The magnetic flux 61 flows along a V shape viewed from the axial direction of the rotor 2. That is, the magnetic flux 61 flows through the portion (q-axis) of the rotor core 21 having a large permeance in the rotor 2. Specifically, as shown in FIG. 9, for example, the magnetic flux 61 flows along the V shape in the V-shaped inner side (not shown) and the outer region formed by the two permanent magnets 24 </ b> A.

  On the other hand, the magnetic flux 62 flows so as to pass through one of the adjacent permanent magnets 24 </ b> A to 24 </ b> H each having a V shape in the rotor 2. Specifically, as shown in FIG. 9, for example, the magnetic flux 62 flows through the permanent magnet 24A and the permanent magnet 24B. That is, the magnetic flux 62 flows through a region (d-axis) where permeance is small.

  The magnetic flux 62 flows in a region (d-axis) in which the permeance is smaller in the rotor 2 than the magnetic flux 61. As described above, by suppressing the increase in inductance in the d-axis direction, the difference between the d-axis inductance and the q-axis inductance is increased, and as a result, the reluctance torque can be increased.

  Next, the reason why the reduction of the reluctance torque can be suppressed by providing the embedded magnet type rotating machine 100 with the end surface fixed magnet 3 will be described.

  As in the embedded magnet type rotating machine described in Patent Document 1, a permanent magnet is fixed to the end face in the axial direction of the rotor 2, and a rotor yoke facing the permanent magnet in the axial direction and having a large permeance is disposed. Consider the case. In this case, the magnetic flux 62 flowing in the d-axis direction flows not only along the broken-line arrow shown in FIG. 9, but also flows through the permanent magnet fixed to the axial end surface of the rotor 2 and the rotor yoke. As shown in FIG. 9, for example, the magnetic flux 62 flows from the region between the two V-shaped permanent magnets 24B to the rotor yoke through the permanent magnets fixed to the end faces. The magnetic flux 62 that has flowed to the rotor yoke forms a magnetic flux that flows through a permanent magnet fixed to the end face and flows in a region between the two permanent magnets 24A.

  Thus, in the conventional embedded magnet type rotating machine, a parallel circuit is formed by two magnetic circuits in the d-axis direction, and the permeance of the parallel circuit is larger than the permeance of each of the two magnetic circuits. As the permeance of the entire magnetic circuit increases, the d-axis inductance increases, so the difference between the d-axis inductance and the q-axis inductance decreases. As a result, in the conventional embedded magnet type rotating machine, the reluctance decreases with the provision of the rotor yoke.

  However, in the embedded magnet type rotating machine 100 of the present invention, it is not necessary to provide a rotor yoke. Therefore, since the parallel circuit as described above is not formed, an increase in inductance in the d-axis direction is suppressed. As a result, since the difference between the inductance in the d-axis direction and the inductance in the q-axis direction is maintained, a decrease in reluctance torque can be prevented.

  Further, in the conventional embedded magnet type rotating machine, the inductance of the rotor 2 in the d-axis direction increases. The increase in inductance acts in the direction in which the phase difference between the current and voltage in the coil 13 approaches 90 °. As a result, the power factor is reduced in the conventional embedded magnet type rotating machine. On the other hand, in the embedded magnet type rotating machine 100, since an increase in inductance is suppressed, a decrease in power factor is suppressed as compared with a conventional embedded magnet type rotating machine.

  In the conventional embedded magnet type rotating machine, the permanent magnets 24A to 24H of the rotor 2 and the magnetic flux passing through the rotor yoke may be short-circuited. Since the short-circuited magnetic flux does not go to the stator 1, the magnet torque decreases in the conventional embedded magnet type rotating machine. On the other hand, since the rotor magnet is not provided in the embedded magnet type rotating machine 100 of the present invention, the magnetic flux is prevented from being short-circuited between the permanent magnets 24A to 24H of the rotor 2 and the rotor yoke. Therefore, since the embedded magnet type rotating machine 100 of the present invention can use the magnet torque more effectively than the conventional embedded magnet type rotating machine, it can be driven with high output and high efficiency.

{Modifications}
In addition, in the said embodiment, although the case where the end surface fixed magnet 3 was a cyclic | annular polar anisotropic magnet was demonstrated, it is not restricted to this. The end surface fixed magnet 3 may be configured by arranging a plurality of arc-shaped polar anisotropic magnets in an annular shape. FIG. 10A is a diagram showing an arc-shaped polar anisotropic magnet 61 having a central angle of 90 degrees. 10B is a BB cross-sectional view of the polar anisotropic magnet 61 shown in FIG. 10A.

  As shown in FIG. 10A, the polar anisotropic magnet 61 has magnetic poles 61A to 61C. The magnetic poles 61 </ b> A to 61 </ b> C are located on a facing surface 65 that faces the end surface of the rotor core 21 in the axial direction. A magnetic flux 33 is formed from the magnetic poles 61B toward 61A, and is formed from the magnetic pole 61C toward the magnetic pole 61A. Accordingly, the magnetic flux 33 flows along the circumferential direction of the polar anisotropic magnet 61. As shown in FIG. 10B, the magnetic flux 33 is formed not only along the circumferential direction but also in a U shape with respect to the axial direction. Therefore, by arranging the four polar anisotropic magnets 61 in an annular shape, the end face fixed magnet 3 that forms the magnetic flux 33 shown in FIGS. 4 and 5 can be configured.

  Moreover, you may comprise the end surface fixed magnet 3 without using a polar anisotropic magnet. For example, the end face fixed magnet 3 may be configured by forming a Halbach array using a plurality of linearly magnetized permanent magnets. FIG. 11 is a cross-sectional view of the end surface fixed magnet 3 when configured in a Halbach array. The cross-sectional view shown in FIG. 11 corresponds to the AA cross-sectional view shown in FIG.

  As shown in FIG. 11, the end surface fixed magnet 3 is composed of a plurality of permanent magnets including permanent magnets 71 to 77. The arrows in each of the permanent magnets 71 to 77 indicate the magnetization direction. Each permanent magnet is magnetized linearly. Since the permanent magnet 71 forms a magnetic flux 33 from the magnetic pole 31B to the magnetic pole 31C, the permanent magnet 71 is arranged so that the magnetization direction is the direction from the magnetic pole 31B to the magnetic pole 31C (leftward in FIG. 11).

  The permanent magnet 72 corresponds to the magnetic pole 31B (S pole) and is arranged so that the magnetization direction is a direction (downward in FIG. 11) from the facing surface 32 toward the exposed surface 35. The permanent magnet 73 is arranged so that the magnetization direction is a direction (rightward in FIG. 11) from the magnetic pole 31B to the magnetic pole 31A in order to form the magnetic flux 33 from the magnetic pole 31B to the magnetic pole 31A. Although not shown in the figure, a magnetic flux obliquely downward to the right is formed between the permanent magnet 72 and the permanent magnet 73. In other words, the magnetic flux is formed so as to complement the path between the magnetization direction of the permanent magnet 72 and the magnetization direction of the permanent magnet 73.

  The permanent magnet 74 corresponds to the magnetic pole 31A (N pole), and is arranged such that the magnetization direction is a direction (upward in FIG. 11) from the exposed surface 35 toward the facing surface 32. The permanent magnet 75 forms a magnetic flux 33 from the magnetic pole 31H to the magnetic pole 31A, and is arranged so that the magnetization direction is the direction from the magnetic pole 31H to the magnetic pole 31A (leftward in FIG. 11).

  The permanent magnet 76 corresponds to the magnetic pole 31H (S pole), and is arranged such that the magnetization direction is a direction (downward in FIG. 11) from the facing surface 32 toward the exposed surface 35. The permanent magnet 77 forms a magnetic flux 33 from the magnetic pole 31H toward the magnetic pole 31G, and is arranged so that the magnetization direction is a direction (rightward in FIG. 11) from the magnetic pole 31H toward the magnetic pole 31G.

  Thus, the end surface fixed magnet 3 can be configured by forming a Halbach array by using a plurality of linearly magnetized permanent magnets. Although FIG. 11 shows a case where the number of divisions of the Halbach array is 3, the number of divisions may be 4 or more. When the end face fixed magnet 3 is configured by the Halbach array, the number of linearly magnetized permanent magnets changes according to the number of divisions. By adopting this configuration, it can be appropriately changed according to the application, and the degree of freedom in design is improved.

  Moreover, in the said embodiment, although the case where the end surface fixed magnet 3 was cyclic | annular was demonstrated, it is not restricted to this. The shape of the outer periphery and the inner periphery of the end surface fixed magnet 3 may be polygonal. That is, the end surface fixed magnet 3 is fixed to the end surface of the rotor 2 in the axial direction, and the S pole from which the magnetic flux flows in from the end surface side of the rotor 2 and the N pole from which the magnetic flux flows out toward the end surface side of the rotor 2. And a magnetic flux from the S pole to the N pole.

  Moreover, in the said embodiment, although the example in which the whole end surface fixed magnet 3 was exposed was demonstrated, it is not restricted to this. For example, you may make it cover at least one part of the end surface fixed magnet 3 using the holding member which consists of nonmagnetic materials.

  FIG. 12 is a view showing the end surface fixed magnet 3 to which the holding member 4 is attached. As shown in FIG. 12, the holding member 4 is attached to the end surface fixed magnet 3 so as to cover a part of the side surface on the circumferential side of the end surface fixed magnet 3 and the exposed surface 35. The holding member 4 is made of a nonmagnetic material.

  Even when the holding member 4 is used, the magnetic flux 61 generated in the coil 13 is formed of a nonmagnetic material, so that the reluctance torque and the magnet torque are reduced as in the above embodiment. Can be suppressed. Further, by fixing the holding member 4 together with the end surface fixing magnet 3 to the rotor core 21, the fixing strength of the end surface fixing magnet 3 to the rotor 2 can be increased, and the end surface fixing magnet 3 is detached from the rotor 2. Can be prevented. Moreover, even if the end surface fixed magnet 3 is damaged by the rotation of the rotor 2, scattering of the damaged end surface fixed magnet 3 can be prevented.

  Moreover, in the said embodiment, although the two end surface fixed magnets were each fixed to both of the two end surfaces of the rotor 2 in an axial direction, it was not restricted to this. In this case, one end surface fixed magnet may be fixed to only one of the two end surfaces of the rotor 2 in the axial direction.

  Further, in the above embodiment, an example in which the embedded magnet type rotating machine 100 is an inner rotor type has been described. However, the embedded magnet type rotating machine 100 is an outer rotor in which the rotor 2 rotates on the outer peripheral side of the stator 1. It may be a rotor type.

  While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

DESCRIPTION OF SYMBOLS 100 Embedded magnet type rotary machine 1 Stator 2 Rotor 3 End surface fixed magnet 4 Holding member 21 Rotor core 22A-22H Magnet arrangement part 23 Magnet insertion space 24A-24H, 71-77 Permanent magnet 31A-31, 61A-61C Magnetic pole 32 Opposing surface 33, magnetic flux (direction of magnetic flux)
35 Exposed surfaces 51-55 Magnetic flux (direction of magnetic flux)
61 Polar anisotropic magnet

Claims (3)

A stator,
A rotor provided coaxially with the stator and having an embedded magnet;
An end face fixing magnet fixed to at least one end face in the axial direction of the rotor,
The end face fixed magnet is:
A first magnetic pole disposed on a facing surface that is a surface facing the one end surface;
A second magnetic pole disposed adjacent to the first magnetic pole on the opposing surface;
An embedded magnet type rotating machine that forms a magnetic flux from the first magnetic pole toward the second magnetic pole. The interior magnet type rotating machine according to claim 1,
The end face fixed magnet is an embedded magnet type rotating machine composed of a polar anisotropic magnet. The interior magnet type rotating machine according to claim 1,
The end face fixed magnet is:
Constituting the first magnetic pole, a first permanent magnet magnetized in a direction from the facing surface toward the surface opposite to the facing surface;
A second permanent magnet constituting the second magnetic pole and magnetized in a direction from the opposite surface to the opposing surface;
A third permanent magnet that forms the magnetic flux and is magnetized in a direction from the first permanent magnet toward the second permanent magnet;
The first permanent magnet, the second permanent magnet, and the third permanent magnet are embedded magnet type rotating machines arranged in a Halbach array.

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