JP2012249347A - Rotor of axial gap rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an output torque per unit volume of an entire rotary electric machine.SOLUTION: A rotor 300 constituting an axial gap type rotary electric machine comprises: a plurality of first permanent magnet parts 323 having a magnetic pole direction along a circumferential direction of the rotor 300 and spaced from each other in the circumferential direction of the rotor 300; a plurality of core parts 324 arranged between the first permanent magnet parts 323 adjacent to each other in the circumferential direction and forming gap faces; and a plurality of second permanent magnet parts 322 having the magnetic pole direction along a rotary shaft direction and arranged between the first permanent magnet parts 323 adjacent to each other in the circumferential direction and on a side opposite to the gap face of each core part 324. The magnetic pole directions of the first permanent magnet parts 323 adjacent to each other in the circumferential direction are opposite to each other. A magnetic pole of the second permanent magnet part 322 identical to the magnetic poles of the first permanent magnet parts 323 arranged on both circumferential sides when seen from each core part 324 and directed to each core part 324 is directed to each core part 324.

Description

  The present invention relates to a rotor of an axial gap rotating electrical machine, and more particularly to the arrangement of permanent magnets and cores in the rotor of an axial gap rotating electrical machine.

  As a rotating electrical machine used for at least one of an electric motor and a generator, an axial gap rotating electrical machine in which a rotor and a stator are arranged so that a gap surface is perpendicular to a rotating shaft is known. In the rotor of the axial gap rotating electrical machine disclosed in Patent Document 1, a plurality of permanent magnets and a plurality of cores are alternately arranged in the circumferential direction of the rotor, and each permanent magnet has a magnetic pole direction in the circumferential direction and a core. The magnets are arranged so that the magnetic pole directions of adjacent permanent magnets are opposite to each other. And in the technique disclosed in Patent Document 1, for example, the axial thickness of the permanent magnet is configured to decrease from the radially outer side to the radially inner side, thereby preventing magnetic saturation of the core, The torque output of the rotating electrical machine per unit volume of the permanent magnet is improved.

JP 2005-253188 A

  However, the above prior art aims to improve the output torque of the rotating electrical machine per unit volume of the permanent magnet, and it cannot be said that sufficient improvements have been made to improve the output torque per unit volume of the entire rotating electrical machine. It was.

  The main advantage of the present invention is to provide a technique capable of improving the output torque per unit volume of the entire rotating electrical machine.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.

[Application Example 1] A rotor having a gap surface disposed opposite to a stator in the rotation axis direction and constituting an axial gap type rotating electrical machine,
A plurality of first permanent magnet portions having a magnetic pole direction along the circumferential direction of the rotor and arranged at intervals along the circumferential direction, the first permanent magnets being adjacent to each other in the circumferential direction A plurality of first permanent magnet parts, wherein the magnet parts have opposite magnetic pole directions;
A plurality of core portions that are respectively disposed between the first permanent magnet portions adjacent in the circumferential direction and that form the gap surface;
A plurality of first magnets each having a magnetic pole direction along the rotation axis direction and disposed between the first permanent magnet portions adjacent to each other in the circumferential direction and opposite to the gap surface of each core portion. Two permanent magnet portions, wherein each core portion has the same magnetic pole as that of the first permanent magnet portion disposed on both sides in the circumferential direction when viewed from each core portion is directed to each core portion. The plurality of second permanent magnet portions facing toward each other;
A rotor.

  In addition to the first permanent magnet portions disposed on both sides in the circumferential direction when viewed from the respective core portions, the rotor having the above-described configuration includes the second permanent magnet portions disposed on the side opposite to the gap surface of each core portion. It has. And the 2nd permanent magnet part has the same magnetic pole as the magnetic pole which the 1st permanent magnet part arrange | positioned at the both sides of the circumferential direction seeing from each core part has directed with respect to each core part with respect to each core part. I am aiming. As a result, the magnetic flux generated by the permanent magnet from the gap surface of each core portion of the rotor toward the stator coil is a combined magnetic flux of the magnetic flux generated by the first permanent magnet portion and the magnetic flux generated by the second permanent magnet portion. As a result, the maximum value of the armature flux linkage by the permanent magnet can be increased as compared with the case where the second permanent magnet is not provided. As a result, it is possible to improve the magnet torque of the rotating electrical machine that increases in proportion to the maximum value of the armature flux linkage by the permanent magnet.

  Further, in the rotor having the above-described configuration, the magnetic path of the d-axis magnetic flux generated by the stator coil sandwiches the first permanent magnet portion from the gap surface of one core portion through the inside of the rotor in the circumferential direction of the core portion. It becomes the path | route which reaches to another adjacent core part. In addition to the first permanent magnet portion, a second permanent magnet portion is disposed in this path. As a result, the magnetic resistance in this path is increased, so that the d-axis inductance Ld is reduced as compared with the case where the second permanent magnet portion is not disposed. As a result, the salient pole ratio increases, so that the reluctance torque of the rotating electrical machine can be improved.

  By improving the magnet torque and the reluctance torque described above, the output torque per unit volume of the entire rotating electrical machine (or the entire rotor), and hence the maximum output (output torque × maximum value of the number of rotations) can be improved. .

[Application Example 2] The rotor according to Application Example 1, further comprising:
When the core portion is called a first core portion, the second core portion is different from the first core portion,
The second core part is a rotor arranged on the side opposite to the gap surface side of the plurality of first permanent magnet parts and the plurality of second permanent magnet parts.

  According to the above configuration, from the magnetic pole opposite to the gap surface side of one second permanent magnet portion, another adjacent adjacent sandwiching the first permanent magnet portion in the circumferential direction of the second permanent magnet portion. The second core portion is disposed in the magnetic path of the magnetic flux reaching the magnetic pole on the side opposite to the gap surface side of the second permanent magnet. As a result, the path of the magnetic flux of the second permanent magnet can be secured and the magnetic flux passing through the first core portion can be increased, so that the magnet torque of the rotating electrical machine can be improved.

  It should be noted that the present invention can be realized in various aspects, and can be realized in aspects such as an axial gap type rotating electrical machine and a drive device including the rotating electrical machine.

FIG. 2 is a schematic diagram showing an external configuration of a first rotor 300 and an external configuration of a rotating electrical machine 1000 using the first rotor 300 as an embodiment of the present invention. FIG. 3 is a diagram illustrating a schematic configuration of a stator 200. 4 is an exploded perspective view of a first rotor 300. FIG. 4 is an exploded perspective view of a field magnet section 320 of the first rotor 300. FIG. It is the figure which illustrated the structure for 1 pole pair in the circumferential direction about the cross section (FF cross section) parallel to the axial direction of the site | part shown with a dashed-dotted line in FIG. It is the schematic which shows the external appearance structure of the field part 520 of the rotor in a comparative example. It is a 1st figure for demonstrating the advantage of the rotary electric machine 1000 in an Example. It is a 2nd figure for demonstrating the advantage of the rotary electric machine 1000 in an Example. It is a graph which shows the output characteristic of the rotary electric machine 1000 in an Example, and the rotary electric machine in a comparative example.

  Next, embodiments of the present invention will be described based on examples and modifications.

A. Example:
FIG. 1 shows an external configuration (FIG. 1A) of a first rotor 300 as an embodiment of the present invention and an external configuration of a rotating electrical machine 1000 using the first rotor 300 (FIG. 1B). FIG. The rotating electrical machine 1000 is an axial gap type 8-pole rotating electrical machine having an axis A as a rotational axis, and includes a stator 200 and a first rotor 300 and a second rotor disposed on both sides of the stator 200 in the rotational axis direction. 400 (FIG. 1B). The first rotor 300 has a gap surface GS3 that is disposed opposite to the stator 200 on one side in the rotational axis direction (FIG. 1A), and the second rotor 400 is in relation to the stator 200. It has a gap surface disposed opposite to one side in the direction of the rotation axis (not shown). Hereinafter, the direction along the rotation axis A is simply referred to as the axial direction, the direction passing through the rotation axis A and orthogonal to the rotation axis A is referred to as the radial direction, and the intersection with the rotation axis A is centered on the plane orthogonal to the rotation axis. The direction along the circle is called the circumferential direction. Further, when the first rotor 300 and the second rotor 400 are described, the direction facing the stator 200 among the directions along the axial direction, that is, the direction on the side where the gap surface is disposed is the stator facing direction. Also called. In FIG. 1, the stator facing direction of the first rotor 300 is the right direction, and the stator facing direction of the second rotor 400 is the left direction.

  FIG. 2 is a diagram illustrating a schematic configuration of the stator 200. As shown in FIG. 2A, the stator 200 includes a plurality of stator cores 201 having a triangular prism shape whose cross-sectional shape perpendicular to the rotation axis A is a substantially isosceles triangle, and a concentration wound around the side surface of each stator core 201. Winding coil 202. The plurality of stator cores 201 around which the concentrated winding coil 202 is wound are arranged side by side in the circumferential direction, and form a substantially cylindrical shape having a hole H1 through which a rotor shaft (described later: FIG. 3) passes. The end surfaces of each stator core 201 facing the first rotor 300 are arranged on the same plane, and form a gap surface GS1 facing the first rotor 300. The end surfaces of each stator core 201 facing the second rotor 400 are arranged on the same plane, and form a gap surface GS2 facing the second rotor 400. In addition, the plurality of concentrated winding coils 202 are divided into three groups of four concentrated winding coils 202 located 90 degrees apart at a mechanical angle in the circumferential direction, and three-phase currents having different phases are energized for each group. Is done. The rotation control of the rotating electrical machine 1000 is performed by the three-phase current that is passed through each concentrated winding coil 202.

  The stator 200 is fixed to a case (not shown) via two stator fixing members 210 formed of a nonmagnetic material. That is, as shown in FIG. 2B, the stator 200 includes a hole 213 through which a rotor shaft (described later: FIG. 3) passes, a plurality of holes 212 into which end portions of the respective stator cores 201 are fitted, and a plurality of bolts. Are sandwiched from both sides in the axial direction by two stator fixing members 210 having holes. The two stator fixing members 210 are fixed to a case (not shown) with bolts.

  The configuration of the first rotor 300 and the second rotor 400 will be described with reference to FIGS. FIG. 3 is an exploded perspective view of the first rotor 300. FIG. 4 is an exploded perspective view of the field part 320 of the first rotor 300. The first rotor 300 includes a field magnet part 320 including a permanent magnet for generating magnetic flux, a non-magnetic support member 311 to which the field magnet part 320 is fixed, and a shaft body 312. And.

  Since the second rotor 400 has the same configuration as that of the first rotor 300, the configuration of the second rotor 400 will be mainly described with reference to the configuration of the first rotor 300 while appropriately explaining the configuration. explain. The shaft main body 312 of the first rotor 300 and the shaft main body of the second rotor 400 are coupled inside the hole H1 (FIG. 2) of the stator 200 when assembled. The outer end 312a of the shaft body 312 of the first rotor 300 and the outer end (not shown) of the shaft body of the second rotor 400 are rotatably supported by the case via bearings. As a result, the first rotor 300 and the second rotor 400 rotate integrally around the rotation axis A.

  The field portion 320 of the first rotor 300 includes the same number of first permanent magnets 323 (FIGS. 3 and 4C) as the number of poles (8 in this embodiment), and the same number of second magnets as the number of poles. Permanent magnets 322 (FIGS. 3 and 4B), the same number of poles as the first cores 324 (FIGS. 3 and 4D), and the second cores 321 (FIGS. 3 and 4 (b)). a)). The first permanent magnet 323 and the second permanent magnet 322 are ferrite magnets. The first core 324 and the second core 321 are made of a soft magnetic material. Specifically, the first core 324 and the second core 321 are dust cores in which an insulating resin is mixed with iron powder and compression-molded with a mold.

  Each first permanent magnet 323 has a square bar shape extending in the radial direction. The plurality of first permanent magnets 323 are arranged at equal intervals along the circumferential direction in the field magnet portion 320. The axial positions of the plurality of first permanent magnets 323 are the same. The cross-sectional shape perpendicular to the radial direction of each first permanent magnet 323 is a rectangle. The length of the side along the circumferential direction of the rectangle is the longest on the radially outer side and is gradually shortened toward the inner side in the radial direction. The length of the side along the axial direction of the rectangle is Constant regardless of position. The N pole magnetized surface 323N and the S pole magnetized surface 323S (FIG. 4C) of each first permanent magnet 323 are substantially perpendicular to the circumferential direction.

  The magnetic pole direction of each first permanent magnet 323 (the direction from the S pole to the N pole) of the first permanent magnet 323 is along the circumferential direction as indicated by a white arrow on the first permanent magnet 323 in FIG. Then, the magnetic pole directions of the first permanent magnets 323 adjacent in the circumferential direction are opposite to each other. That is, the N-pole magnetized surface 323N and the S-pole magnetized surface 323S (FIG. 4C) of the first permanent magnet 323 are substantially perpendicular to the circumferential direction, and N of the first permanent magnet 323 adjacent to each other. The pole magnetized surfaces 323N face each other.

  The plurality of first cores 324 are disposed between the second permanent magnets 322 adjacent in the circumferential direction. The positions in the axial direction of the plurality of first cores 324 are the same. Each first core 324 includes a main body portion 324a and a gap surface forming portion 324b disposed in the stator facing direction of the main body portion 324a. The main body 324a has a substantially fan-shaped cross section perpendicular to the axial direction, and the cross sectional shape extends in the axial direction. The length of the main body 324a in the axial direction is about half of the length of the first permanent magnet 323 in the axial direction. The surface of the gap surface forming portion 324b in the stator facing direction has a sector shape slightly larger in the circumferential direction than the sector shape of the main body portion 324a. The surfaces in the stator facing direction of the gap surface forming portions 324b of the first cores 324 are arranged on the same surface, and form the gap surface GS3 of the first rotor 300 described above.

  The plurality of second permanent magnets 322 are disposed between the first permanent magnets 323 adjacent to each other in the circumferential direction, and are adjacent to the surface of each first core 324 on the opposite side to the stator facing direction. . That is, each second permanent magnet 322 is arranged on the opposite side of the gap surface side of each first core 324. The axial positions of the plurality of second permanent magnets 322 are the same. Each second permanent magnet 322 has substantially the same shape as the main body 324 a of the first core 324. That is, the second permanent magnet 322 has a substantially sector-shaped cross section perpendicular to the axial direction and a shape in which the cross sectional shape extends in the axial direction. The axial length of the second permanent magnet 322 is about half of the axial length of the first permanent magnet 323. The surface of the plurality of second permanent magnets 322 opposite to the stator facing direction is located on the same plane as the surface of the first permanent magnet 323 opposite to the stator facing direction.

  The N-pole magnetized surface 322N and the S-pole magnetized surface 322S of the second permanent magnet 322 are substantially fan-shaped surfaces perpendicular to the axial direction (FIG. 4B). That is, the magnetic pole direction of the second permanent magnet 322 is along the axial direction as indicated by a white arrow on the second permanent magnet 322 in FIG. And the magnetic pole direction of the 2nd permanent magnet 322 adjacent to the circumferential direction on both sides of the 1st permanent magnet 323 has faced the mutually opposite direction (FIG. 3). In addition, each second permanent magnet 322 includes first permanent magnets 323 arranged on both sides in the circumferential direction of the first core 324 with respect to the first core 324 located in the stator facing direction. The same magnetic pole as that directed to the first core 324 is directed. That is, one first core 324 faces the magnetized surfaces of the same magnetic poles of two first permanent magnets 323 and one second permanent magnet 322.

  The second core 321 has a disk shape having a hole H3 through which the shaft body 312 of the rotor shaft 310 passes in the center. The surface of the second core 321 in the stator facing direction is opposite to the entire surface of the plurality of first permanent magnets 323 opposite to the stator facing direction and the plurality of second permanent magnets 322 in the stator facing direction. It arrange | positions so that the whole surface of a direction may be covered.

  Here, since the number of poles of the field part 320 is 8, that is, the number of pole pairs is 4, the positions 90 degrees apart from each other in the circumferential direction are equivalent. That is, the same configuration is repeated four cycles, with the configuration of 90 degrees in mechanical angle in the circumferential direction as one cycle (corresponding to 360 degrees in electrical angle). FIG. 5 is a diagram illustrating a configuration of one period (one pole pair) in the circumferential direction of a cross section (FF cross section) parallel to the axial direction of a portion indicated by a one-dot broken line in FIG. In FIG. 5, as indicated by a broken line in FIG. 3, the center in the circumferential direction of one first permanent magnet 323 is set to a position of 0 degree in electrical angle, and one period (electrical) from this position counterclockwise in the circumferential direction. A position up to a position 360 degrees apart is shown. In FIG. 5, for the sake of easy understanding, the configurations of the stator 200 and the second rotor 400 are also shown corresponding to one cycle. Hereinafter, further description will be given with reference to FIG.

  Since the configuration of the second rotor 400 is the same as the configuration of the first rotor 300 as described above, the sign of each component of the second rotor 400 is “4” in the first digit. The code | symbol which made the digit after the 2nd digit of the code | symbol of the corresponding component of the 1st rotor 300 the same is used. For example, the first permanent magnet of the second rotor 400 is denoted by reference numeral “423”, and the first core of the second rotor 400 is denoted by reference numeral “424”.

  As shown in FIG. 5, the first rotor 300 of the first rotor 300 and the stator 200 are opposed to each other in the axial direction (position overlapping when viewed from the axial direction). One permanent magnet 423 is arranged. The magnetic pole direction of the first permanent magnet 323 of the first rotor 300 and the magnetic pole direction of the first permanent magnet 423 of the second rotor 400 facing in the axial direction are opposite to each other.

  Similarly, as illustrated in FIG. 5, the first permanent magnet 423 of the second rotor 400 is located at a position facing the second permanent magnet 322 of the first rotor 300 and the stator 200 in the axial direction. Be placed. The magnetic pole direction of the second permanent magnet 322 of the first rotor 300 and the magnetic pole direction of the second permanent magnet 422 of the second rotor 400 facing the axial direction are in the same direction. That is, the magnetic pole surface on the stator 200 side of the second permanent magnet 322 of the first rotor 300 and the magnetic pole surface on the stator 200 side of the second permanent magnet 422 of the second rotor 400 facing each other in the axial direction are mutually connected. It becomes a magnetic pole surface of a different magnetic pole (FIG. 5).

  Further, as shown in FIG. 5, the first core 424 of the second rotor 400 is arranged at a position facing the first core 324 of the first rotor 300 and the stator 200 in the axial direction. .

  The magnetic path of the magnetic flux generated by the field part 320 of the first rotor 300 and the field part of the second rotor 400 configured as described above will be schematically described as a typical path. 5 includes a first route indicated by a solid line and a second route indicated by a broken line. The first path is mainly a magnetic path of the magnetic flux of the first permanent magnets 323 and 423 of the first rotor 300 and the second rotor 400. The second path is mainly a magnetic path of magnetic fluxes of the second permanent magnets 322 and 422 of the first rotor 300 and the second rotor 400.

  The first path passes through the gap surface GS3 of the first core 324 adjacent to the N-pole magnetized surface 323N of the first permanent magnet 323 of the first rotor 300, and the first path of the stator 200 and the second rotor 400 is passed through. This includes a path that passes through the gap surface GS4 of one core 424 and reaches the S-pole magnetized surface 423S of the first permanent magnet 423 adjacent to the first core 424. The first path passes through the gap surface GS4 of the first core 424 adjacent to the N-pole magnetized surface 423N of the first permanent magnet 423 of the second rotor 400, and the stator 200 and the first rotor 300. Including a path that passes through the gap surface GS3 of the first core 324 and reaches the S-pole magnetized surface 323S of the first permanent magnet 323 adjacent to the first core 324.

  The second path includes a magnetized surface (N-pole magnetized surface 322N or S-pole magnetized surface 322S) facing the gap surface GS3 side of the second permanent magnet 322 of the first rotor 300, and the second permanent magnet. A path connecting the magnet 322 and the magnetized surface (S-pole magnetized surface 422S or N-pole magnetized surface 422N) facing the gap surface GS4 of the second permanent magnet 422 of the second rotor 400 facing in the axial direction. including. Further, the second path extends from the magnetized surface (N-pole magnetized surface 322N or S-pole magnetized surface 322S) on the second core 321 side of the second permanent magnet 322 of the first rotor 300, to the second path. The second permanent magnet 322 adjacent to the second permanent magnet 322 passing through the core 321 and sandwiching the first permanent magnet 323 in the circumferential direction of the second permanent magnet 322 (S-pole magnetized surface) 322S or N-pole magnetized surface 322N). Further, the second path extends from the magnetized surface (N-pole magnetized surface 422N or S-pole magnetized surface 422S) of the second permanent magnet 422 of the second rotor 400 on the second core 421 side to the second path. The second permanent magnet 422 adjacent to the second permanent magnet 422 passing through the core 421 and sandwiching the first permanent magnet 423 in the circumferential direction of the second permanent magnet 422 (S-pole magnetized surface) 422S or N pole magnetized surface 422N).

  Advantages of the first rotor 300 and the second rotor 400 configured as described above will be described in comparison with a comparative example. FIG. 6 is a schematic view showing an external configuration of the field portion 520 of the rotor in the comparative example. The field portion 520 in the comparative example has the same physique as the field portion 320 (FIG. 3) in the above-described embodiment. That is, the field part 520 in the comparative example and the field part 320 in the example have a cylindrical shape with the same length in the axial direction and the length in the radial direction, and holes H5 and H2 having the same diameter are formed on the rotating shaft. Each has a central part.

  Unlike the field part 320 in the embodiment, the field part 520 in the comparative example does not include the second permanent magnet 322 and the second core 321. The field magnet portion 520 in the comparative example includes the same number of permanent magnets 523 as the plurality of first permanent magnets 323 in the embodiment. The permanent magnet 523 is the same ferrite magnet as the plurality of first permanent magnets 323 in the embodiment. The circumferential arrangement position of each permanent magnet 523 is the same as the circumferential arrangement position of each first permanent magnet 323 in the embodiment. The axial length of the permanent magnet 523 is longer than the first permanent magnet 323 by the axial thickness of the second core 321 of the field part 320 in the embodiment.

  The field part 520 in the comparative example includes a core 524 between the adjacent permanent magnets 523 at intervals in the circumferential direction. That is, the number of the cores 524 is the same as the number of the first cores 324 in the embodiment, and the circumferential positions of the permanent magnets 523 are the same as the circumferential positions of the first permanent magnets 323 in the embodiment. is there. The core 524 is a dust core made of the same material and molding method as the first core 324 in the embodiment. The axial length of the core 524 is equal to the first thickness in the embodiment by the thickness of the second permanent magnet 322 in the field portion 320 in the embodiment and the axial thickness of the second core 321 in the embodiment. Longer than core 324.

  The field portion 520 in the comparative example has the number of poles of 8 as in the field portion 320 in the embodiment, and therefore the positions 90 degrees apart from each other in the circumferential direction are equivalent. That is, the same configuration is repeated four cycles, with the configuration of 90 degrees in mechanical angle in the circumferential direction as one cycle (corresponding to 360 degrees in electrical angle).

  The pair of rotors including the field portion 520 in the comparative example described above is arranged so that the magnetic pole directions of the permanent magnets 523 facing in the axial direction are opposite to both sides in the axial direction of the same stator as the stator 200 in the embodiment. A rotating electrical machine configured to be opposed to the rotating electrical machine is a rotating electrical machine in the comparative example.

Here, the torque T when the rotating electrical machine is used as a motor is expressed by the following equation (1) using a d, q conversion model expressed by the rotating electrical machine in a so-called d, q axis coordinate system.
T = M · Iq− (Lq−Ld) Id · Iq (1)
Here, M represents a counter electromotive force constant, Lq represents a q-axis inductance, Ld represents a d-axis inductance, Id represents a d-axis current, and Iq represents a q-axis current. The first term represents magnet torque, and the second term represents reluctance torque. When driving and controlling a rotary electric machine, since Lq> Ld is generally satisfied, a positive value q-axis current Iq and a negative value d-axis current Id are converted into a three-phase alternating current, and controlled. The second term is a positive value. As understood from the equation (1), the magnet torque is proportional to the back electromotive force constant M, and the reluctance torque is proportional to the salient pole ratio (Lq−Ld). The counter electromotive force constant M corresponds to the maximum value of the armature linkage magnetic flux.

  FIG. 7 is a first diagram for explaining the advantages of the rotating electrical machine 1000 according to the embodiment. Fig.7 (a) is the figure which illustrated one period in the circumferential direction of the FF cross section (refer FIG. 3) of the field part 320 in an Example. FIG. 7B is a diagram illustrating one period in the circumferential direction of the GG section (see FIG. 6) of the field portion 520 in the comparative example. FIG.7 (c) is a graph which compares the counter electromotive force constant of the rotary electric machine 1000 in an Example, and the rotary electric machine in a comparative example. The counter electromotive force constant is normalized by setting the counter electromotive force constant of the rotating electrical machine in the comparative example to 1 based on the value calculated by the magnetic field analysis using the finite element method.

  As shown in FIG. 7A, the first rotor 300 (field portion 320) in the embodiment is a pair of first permanent magnets arranged on both sides in the circumferential direction when viewed from each first core 324. In addition to the H.323, a second permanent magnet 322 is provided on the opposite side of the first core 324 from the gap surface GS3 (the opposite side of the stator facing direction). The second permanent magnet 322 is a magnetic pole in which the first permanent magnets 323 arranged on both sides in the circumferential direction as viewed from the first core 324 adjacent in the stator facing direction are directed toward the first core 324. The same magnetic pole is directed to the first core 324. As a result, the magnetic flux generated by the permanent magnet from the gap surface GS3 toward the stator 200 is a magnetic flux that is a combination of the magnetic flux generated by the first permanent magnet 323 and the magnetic flux generated by the second permanent magnet 322. The same can be said for the second rotor 400.

  On the other hand, as shown in FIG. 7B, the rotor (field portion 520) in the comparative example has only permanent magnets 523 arranged on both sides in the circumferential direction when viewed from each core 524. As a result, the magnetic flux generated by the permanent magnet from the gap surface GS5 toward the stator is only the magnetic flux generated by the permanent magnet 523.

  As can be seen from the above description, according to the first rotor 300 and the second rotor 400 in the embodiment, the magnetic flux generated by the permanent magnet can be increased as compared with the rotor in the comparative example. This increase in magnetic flux by the permanent magnet increases the back electromotive force constant in equation (1). As shown in FIG. 7C, according to the magnetic field analysis using the finite element method, the counter electromotive force constant of the rotating electrical machine 1000 in the example is compared with the counter electromotive force constant of the rotating electrical machine in the comparative example, About 10% larger.

  As described above, according to the first rotor 300 and the second rotor 400 in the embodiment, the counter electromotive force constant can be increased and the magnet torque of the rotating electrical machine can be improved.

  FIG. 8 is a second diagram for explaining the advantages of the rotating electrical machine 1000 according to the embodiment. FIG. 8A shows the same part of the field part 320 as in FIG. 7A. FIG. 8B illustrates the same portion of the field portion 520 in the comparative example as in FIG. 7B. FIG. 8C is a graph comparing salient pole ratios of the rotating electrical machine 1000 in the example and the rotating electrical machine in the comparative example. This salient pole ratio is normalized by setting the d-axis inductance Ld of the rotating electrical machine in the comparative example to 1 based on the value calculated by the magnetic field analysis using the finite element method.

  The solid line arrow shown in FIG. 8A indicates the path of the d-axis magnetic flux (d-axis magnetic path) in the first rotor 300 (field part 320) in the embodiment. Similarly, the solid line arrow shown in FIG. 8B indicates the d-axis magnetic path in the rotor (field portion 520) in the comparative example. In both the example and the comparative example, the d-axis magnetic path is a path that penetrates through a permanent magnet having high magnetic resistance (the first permanent magnet 323 in the example and the permanent magnet 523 in the comparative example) in the circumferential direction. In the first rotor 300 in the embodiment, since the second permanent magnet 322 having a high magnetic resistance is further arranged in this path, the magnetic resistance of the d-axis magnetic path is larger than that in the comparative example. The same can be said for the second rotor 400. Therefore, the d-axis inductance Ld in the rotating electrical machine 1000 in the embodiment is lower than the d-axis inductance Ld in the rotating electrical machine in the comparative example.

  A broken arrow shown in FIG. 8B indicates a typical path (q-axis magnetic path) of the q-axis magnetic flux in the first rotor 300 (field part 320) in the embodiment. Similarly, the solid line arrow shown in FIG. 8B indicates a typical q-axis magnetic path in the first rotor (field portion 520) in the comparative example. In both the example and the comparative example, the q-axis magnetic path is a path that passes through the soft magnetic material having a small magnetic resistance (the first core 324 in the example and the core 524 in the comparative example). The length of the first core 324 in the embodiment in the axial direction is shorter than the length in the axial direction of the core 524 in the comparative example, but as long as the magnetic flux passing through the first core 324 does not reach the saturation magnetic flux density in the embodiment. The magnetoresistance of the q-axis magnetic path is not so great compared to the magnetoresistance of the q-axis magnetic path in the comparative example. Therefore, although the q-axis inductance Lq in the rotating electrical machine 1000 in the embodiment is lower than the q-axis inductance Lq in the rotating electrical machine in the comparative example, the degree of reduction is smaller than the degree of reduction in the d-axis inductance.

  As can be understood from the above description, the salient pole ratio (Lq−Ld) of the rotating electrical machine 1000 in the embodiment is larger than the salient pole ratio of the rotating electrical machine in the comparative example. As shown in FIG. 8C, according to the magnetic field analysis using the finite element method, the salient pole ratio of the rotating electrical machine 1000 in the example is about 4 compared with the salient pole ratio of the rotating electrical machine in the comparative example. % Was bigger.

  As described above, according to the first rotor 300 and the second rotor 400 in the embodiment, the salient pole ratio can be increased and the reluctance torque of the rotating electrical machine can be improved.

  By improving the magnet torque and the reluctance torque as described above, the output torque per unit volume of the entire rotating electrical machine (or the entire rotor) when the rotating electrical machine is operated as an electric motor, and hence the maximum output (output torque x rotational speed). (Maximum value) can be improved. Moreover, when operating a rotary electric machine as a generator, the power generation capability per unit volume can be improved.

  FIG. 9 is a graph showing the output characteristics of the rotating electrical machine 1000 in the example and the rotating electrical machine in the comparative example calculated by the magnetic field analysis using the finite element method. FIG. 9A shows the relationship (field angle characteristics) between the phase difference (field angle) between the magnetic pole position of the rotor and the magnetic field position of the three-phase rotating magnetic field of the stator and the output torque. FIG. 9B shows the relationship (torque-rotational speed characteristics) between the output torque and the rotational speed (the rotational speed per unit time). 9 (a) and 9 (b) compare the cases where each rotating electrical machine is controlled with the same current. 9 (a) and 9 (b), the maximum torque of the rotating electrical machine in the comparative example is shown as 1. FIG. 9A and 9B, the maximum torque of the rotating electrical machine 1000 in the example was about 10.8% larger than the maximum torque of the rotating electrical machine in the comparative example. The maximum output of the rotating electrical machine 1000 in the example was about 21.6% larger than the maximum output of the rotating electrical machine in the comparative example.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) The second core 321 of the field part 320 in the above embodiment is arranged to secure the magnetic path of the magnetic flux of the second permanent magnet 322 and increase the magnetic flux passing through the first core 324. Is preferred, but may be omitted.

(2) The above embodiment is a so-called double rotor type in which rotors (first rotor 300 and second rotor 400) are arranged on both sides of the stator 200 in the axial direction, respectively, but one side of the stator in the axial direction. A configuration in which the rotor is disposed only on the surface may be used.

(3) In the above embodiment, ferrite magnets are used for the first permanent magnets 323 and 423 and the second permanent magnets 322 and 422, but other types of magnets may be used. For example, a rare earth magnet such as a neodymium magnet or a samarium cobalt magnet, an alnico magnet, or the like may be employed. If a rare earth magnet having a stronger magnetic force than a ferrite magnet is employed, a smaller and higher output rotating electrical machine can be produced. On the other hand, if a ferrite magnet is employed as in the present embodiment, a rotating electrical machine having an improved output per unit volume can be manufactured while being inexpensive. Moreover, although the 1st cores 324 and 424 and the 2nd cores 321 and 421 employ | adopted the dust core, arbitrary soft magnetic materials, for example, the laminated body of an electromagnetic steel plate, can be employ | adopted.

(4) In the above embodiment, a rotating electrical machine having 8 poles has been described as an example, but the number of poles is not limited to this, and rotating electrical machines having any number of poles such as 4 poles, 6 poles, and 10 poles are employed. can do.

(5) In addition, the specific shapes of the rotors 300 and 400 in the above embodiment are merely examples, and can be appropriately modified. For example, in the above-described embodiment, the plurality of first cores 324 are separate from each other, but may be integrated inside in the radial direction, and the first permanent magnets 323 adjacent in the circumferential direction may be integrated. What is necessary is just to provide the core part arrange | positioned between. Similarly, the specific configuration of the stator 200 is an example, and can be appropriately modified. For example, a stator including a stator coil configured by distributed winding may be used.

(6) Although the rotary electric machine 1000 in the said Example is employ | adopted for all the uses which operate | move as at least one of an electric motor and a generator, for example, it can be used as an electric motor and a generator in an electric vehicle or a hybrid vehicle.

  The present invention can be suitably used for a rotor used in an axial gap type rotating electrical machine.

    200 ... Stator, 201 ... Stator core, 202 ... Concentrated winding coil, 210 ... Stator fixing member, 300 ... First rotor, 310 ... Rotor shaft, 311 ... Support member 312 ... Shaft body, 312a ... End, 320 ... Field part, 321 ... Second core, 322 ... Second permanent magnet, 323 ... First permanent Magnets 324 ... first core 400 ... second rotor 421 ... second core 422 ... second permanent magnet 423 ... first permanent magnet 424 ... first core, 1000 ... rotating electric machine, GS1-GS4 ... gap surface

Claims (2)

A rotor having a gap surface disposed opposite to the stator in the rotation axis direction and constituting an axial gap type rotating electrical machine,
A plurality of first permanent magnet portions having a magnetic pole direction along the circumferential direction of the rotor and arranged at intervals along the circumferential direction, the first permanent magnets being adjacent to each other in the circumferential direction A plurality of first permanent magnet parts, wherein the magnet parts have opposite magnetic pole directions;
A plurality of core portions that are respectively disposed between the first permanent magnet portions adjacent in the circumferential direction and that form the gap surface;
A plurality of first magnets each having a magnetic pole direction along the rotation axis direction and disposed between the first permanent magnet portions adjacent to each other in the circumferential direction and opposite to the gap surface of each core portion. Two permanent magnet portions, wherein each core portion has the same magnetic pole as that of the first permanent magnet portion disposed on both sides in the circumferential direction when viewed from each core portion is directed to each core portion. The plurality of second permanent magnet portions facing toward each other;
A rotor. The rotor of claim 1, further comprising:
When the core portion is called a first core portion, the second core portion is different from the first core portion,
The second core part is a rotor arranged on the side opposite to the gap surface side of the plurality of first permanent magnet parts and the plurality of second permanent magnet parts.

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