WO2013084556A1

WO2013084556A1 - Electric motor

Info

Publication number: WO2013084556A1
Application number: PCT/JP2012/073220
Authority: WO
Inventors: 敦誉小柴; 貞一郎千葉
Original assignee: 株式会社小松製作所
Priority date: 2011-12-06
Filing date: 2012-09-11
Publication date: 2013-06-13
Also published as: JP2013121215A

Abstract

This electric motor (1) includes a first rotor (10), a second rotor (20), and a stator (30) having 3×n slots provided with windings (33). With the exclusion of a group of even numbers that are obtained by keeping m and n of the numerical expression 2×m+6×n×(k-1) constant and changing k and that include multiples of 3×n/2 as well as the smallest even number and multiples of the smallest even number, 2×i groups are obtained by changing m, and two even numbers are selected, one from the (j+1)^th group and one from the (2×i-j)^th group respectively, as the number of magnetic poles for the first rotor (10) and the second rotor (20), with i, m, n, and k being integers of 1 or greater, j being an integer between 0 and i-1, and the maximum value of m being 3×n-1.

Description

Electric motor

The present invention relates to an electric motor having a plurality of rotors.

There is an electric motor having two rotors sharing a stator (for example, Patent Document 1).

JP 2006-320187 A

The invention described in Patent Document 1 cannot control each rotor independently. An object of the present invention is to independently control each rotor in an electric motor having two rotors sharing a stator.

The present invention is an annular structure that is disposed between a first rotor and a second rotor that rotate about a rotation axis, and is disposed between the first rotor and the second rotor and that surrounds the periphery of the rotation axis. A stator having 3 × n slots and a plurality of windings arranged in each of the slots, and fixing m and n in the formula 2 × m + 6 × n × (k−1), k Is a group consisting of an even number obtained by changing x, excluding a group containing a multiple of 3 × n / 2, the smallest even number, and the smallest even number multiple, and further changing m from a small value to a large value Two even numbers selected from the (j + 1) -th group and the (2 × i−j) -th group in the 2 × i group obtained in the above are respectively the first rotor and the first rotor. 2 The number of magnetic poles of the rotor It is an electric motor for the butterflies. Here, i, m, n, and k are integers of 1 or more, j is an integer of 0 to i−1, and the maximum value of m is 3 × n−1.

In the present invention, it is preferable that a current obtained by superimposing a current for driving the first rotor and a current for driving the second rotor is applied to the winding of the stator.

In the present invention, it is preferable that the current for driving the first rotor and the current for driving the second rotor are currents having different frequencies and amplitudes.

In the present invention, the winding is preferably a toroidal coil wound in the circumferential direction of the stator.

In the present invention, the first rotor has a portion that engages with a magnet for making the magnetic pole of the first rotor radially outward, and the second rotor has a magnetic pole of the second rotor radially outward. It is preferable to have a portion that engages with the magnet for making the.

In the present invention, it is preferable that the first rotor and the second rotor are arranged in parallel to each other from the front of the rotating shaft to the back with the stator interposed therebetween.

In the present invention, it is preferable that the length of the outer peripheral arc of the slot portion is the same as the length of the inner peripheral arc between the radially outer side and the radially inner side of the stator.

The present invention includes a first rotor and a second rotor that rotate about a rotation axis and that have a magnet that forms a magnetic pole and a portion that engages with the magnet on a radially outer side, the first rotor, and the second rotor. And a stator having 3 × n slots, and arranged in each of the slots and toward the circumferential direction of the stator. A plurality of windings that are wound toroidal coils, and the first rotor and the second rotor are arranged in parallel to each other from the front of the rotating shaft to the back with the stator interposed therebetween. Furthermore, a group consisting of an even number obtained by fixing m and n in the formula 2 × m + 6 × n × (k−1) and changing k, which is a multiple of 3 × n / 2 and The group including the smallest even number and a multiple of the smallest even number is excluded, and the (j + 1) th group and (2 × i−) in the 2 × i groups obtained by changing m from a small value to a large value j) The electric motor characterized in that two even numbers each selected from the first group are the numbers of magnetic poles of the first rotor and the second rotor, respectively. Here, i, m, n, and k are integers of 1 or more, j is an integer of 0 to i−1, and the maximum value of m is 3 × n−1.

In the present invention, in an electric motor having two rotors sharing a stator, each rotor can be controlled independently.

FIG. 1 is a cross-sectional view of the electric motor according to the present embodiment, taken along a plane that passes through the rotation axis and includes the rotation axis. FIG. 2 is a perspective view of the internal structure of the electric motor according to the present embodiment. FIG. 3 is a plan view of the first rotor included in the electric motor according to the present embodiment. FIG. 4 is a plan view of a second rotor included in the electric motor according to the present embodiment. FIG. 5 is a plan view of a stator included in the electric motor according to the present embodiment. FIG. 6 is a cross-sectional view of an electric motor according to a modification of the present embodiment, cut along a plane that passes through the rotation axis and includes the rotation axis. FIG. 7 is a partial cross-sectional view of the electric motor according to the present embodiment cut along a plane orthogonal to the rotation axis. FIG. 8 is a schematic diagram showing the relationship between the electrical angle and phase of the three-phase motor. FIG. 9 is a schematic diagram showing the phase order of the comparative example. FIG. 10 is a schematic diagram showing the phase sequence of the present embodiment. FIG. 11 is a perspective view showing a modification of the stator. FIG. 12 is a partial plan view showing a modification of the stator.

DETAILED DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of components can be made without departing from the scope of the present invention.

<Structure of electric motor>
FIG. 1 is a cross-sectional view of the electric motor according to the present embodiment, taken along a plane that passes through the rotation axis and includes the rotation axis. FIG. 2 is a perspective view of the internal structure of the electric motor according to the present embodiment. FIG. 3 is a plan view of the first rotor included in the electric motor according to the present embodiment. FIG. 4 is a plan view of a second rotor included in the electric motor according to the present embodiment. FIG. 5 is a plan view of a stator included in the electric motor according to the present embodiment. 1 and 6 show different cross sections of the

electric motors

1 and 1a on the upper side and the lower side of the respective drawings based on the rotation axis Zr.

The electric motor 1 includes a first rotor 10, a second rotor 20, and a stator 30. The electric motor 1 is a three-phase electric motor, and the first rotor 10 and the second rotor 20 are driven by a common stator 30. The first rotor 10, the second rotor 20, and the stator 30 are stored in the housing 2. The housing 2 is a cylindrical structure, and the

power transmission shafts

12 and 22 protrude from the through

holes

5 and 6 at both ends, respectively.

The rotation center of the first rotor 10 and the second rotor 20 and the rotation axis Zr are the same. Further, the radial direction of the first rotor 10 and the second rotor 20 and the rotation axis Zr are orthogonal to each other. The first rotor 10 and the second rotor 20 rotate about the rotation axis Zr. Thus, the first rotor 10 and the second rotor 20 rotate around the common rotation axis Zr. The stator 30 is disposed between the first rotor 10 and the second rotor 20. Therefore, the first rotor 10 and the second rotor 20 are located at different positions in the direction in which the rotation axis Zr extends, and are disposed with the stator 30 interposed therebetween. Thus, the first rotor 10 and the second rotor 20 are arranged in parallel to each other from the front (one side) to the back (the other side) of the rotation axis Zr with the stator 30 interposed therebetween.

In the first rotor 10, one of the two end surfaces orthogonal to the rotation axis Zr faces one end surface of the stator 30 orthogonal to the rotation axis Zr. In the second rotor 20, one of the two end surfaces orthogonal to the rotation axis Zr faces the other end surface of the stator 30 orthogonal to the rotation axis Zr. The type of the electric motor 1 is an axial gap type in which a gap between the first rotor 10 and the second rotor 20 and the stator 30 exists in a direction parallel to the rotation axis Zr.

Each of the first rotor 10 and the second rotor 20 includes rotor main bodies (yokes) 11 and 21 as disk-shaped structures,

power transmission shafts

12 and 22 attached to the rotor

main bodies

11 and 21, and the rotor main body 11. , 21 and a plurality of magnets (permanent magnets) 13, 23. The

power transmission shafts

12 and 22 extend from both end faces of the rotor

main bodies

11 and 21 in the direction of the rotation axis Zr. The central axes of the

power transmission shafts

12 and 22 are the same as the central axes of the

rotor bodies

11 and 21. These are also common to the rotation axis Zr of the electric motor 1.

The first rotor 10 has a portion (first magnet engaging portion) 10T that engages with the magnet 13 for creating the magnetic pole of the first rotor 10 on the radially outer side, and the second rotor 20 on the radially outer side. A portion (second magnet engaging portion) 20T that engages with the magnet 23 for forming the magnetic pole of the second rotor 20 is provided. The first magnet engaging portion 10T protrudes from the outer edge portion on the radially outer side of the rotor body 11 in a direction parallel to the rotation axis Zr. Similarly, the second magnet engaging portion 20T protrudes from the outer edge portion on the radially outer side of the rotor body 21 in a direction parallel to the rotation axis Zr.

The magnet 13 of the first rotor 10 is engaged with the first magnet engaging portion 10T. Further, the magnet 23 of the second rotor 20 is engaged with the first magnet engaging portion 20T. By doing in this way, the 1st magnet engaging part 10T and the 2nd magnet engaging part 20T receive the centrifugal force which acts on the

magnets

13 and 23 when the 1st rotor 10 and the 2nd rotor 20 rotate. As a result, since the possibility that the

magnets

13 and 23 come off during the rotation of the first rotor 10 and the second rotor 20 can be reduced, safety is improved.

The stator 30 is an annular structure. The stator 30 is disposed inside the housing 2. The stator 30 includes a stator core 31, teeth 32 provided on the stator core 31, and windings (coils) 33 wound around the stator core 31. The winding 33 is a conductor and is a copper wire in this embodiment. The winding 33 is not limited to a copper wire, and may be an aluminum wire, for example. In the stator 30, the outer peripheral portion 31 S of the stator core 31 is fixed to the inner peripheral portion 2 I of the housing 2. The stator core 31 has a through hole 31H at the center. The structure of the stator 30 will be described later.

The power transmission shaft 12 of the first rotor 10 is supported by the

bearings

3A and 3B. More specifically, in the power transmission shaft 12, one end face side (the side where the magnet 13 is disposed) of the rotor body 11 is the bearing 3A, and the other end face side (the side opposite to the magnet 13) is the bearing 3B. It is supported by. The power transmission shaft 22 of the second rotor 20 is supported by the

bearings

3C and 3D. More specifically, in the power transmission shaft 22, one end surface side (the side where the magnet 23 is disposed) of the rotor body 21 is the bearing 3C, and the other end surface side (the side opposite to the magnet 23) is the bearing 3D. It is supported by.

Bearings

3A and 3C are attached to the through holes 31H of the stator core 31. For this reason, the bearings 3 A and 3 C are supported by the housing 2 via the stator core 31. The bearing 3 B is attached to the through hole 5 of the housing 2, and the bearing 3 D is attached to the through hole 6 of the housing 2. With such a structure, the first rotor 10 is supported by the housing 2 via the

bearings

3A and 3B and the power transmission shaft 12, and the second rotor 20 is housed via the

bearings

3C and 3D and the power transmission shaft 22. Supported by the body 2. The first rotor 10 and the second rotor 20 can rotate independently of the housing 2.

As shown in FIG. 2 and FIG. 3, the plurality of magnets 13 included in the first rotor 10 are N on one end face of the rotor body 11 and around the power transmission shaft 12 in the circumferential direction of the rotor body 11. The poles and S poles are alternately arranged. As shown in FIGS. 2 and 4, the plurality of magnets 23 included in the second rotor 20 are also arranged on one end face of the rotor body 21 and around the power transmission shaft 22 in the circumferential direction of the rotor body 21. The poles and S poles are alternately arranged. In the present embodiment, the

magnets

13N and 23N represent the N pole, and the

magnets

13S and 23S represent the S pole.

Magnets

13 and 23 create magnetic poles.

The

magnets

13 and 23 may be structured to be attached to the surfaces of the rotor bodies 11 and 21 (SPM: Surface Permanent Magnet) or embedded in the rotor bodies 11 and 21 (IPM: Interior Permanent Magnet). Also good. The same applies to the following examples. The

magnets

13 and 23 may be either ring magnets or segment magnets.

The number of magnets 13 included in the first rotor 10 and the number of magnets 23 included in the second rotor 20 are both even numbers. The number of magnets 13 included in the first rotor 10 and the number of magnets 23 included in the second rotor 20 are the number of magnetic poles of the first rotor 10 and the number of magnetic poles of the second rotor 20, respectively. The number of magnetic poles is called the number of poles. In the present embodiment, the number of magnets 13 included in the first rotor 10 is different from the number of magnets 23 included in the second rotor 20. As shown in FIGS. 1 and 2, in the first rotor 10 and the second rotor 20, the

magnets

13 and 23 are opposed to the teeth 32 of the stator 30.

2 and 5, the stator core 31 of the stator 30 includes an annular yoke 34 and a plurality of teeth 32 that are respectively attached to both end surfaces of the yoke 34. The stator core 31 may be formed, for example, by laminating electromagnetic steel plates or by pressing magnetic powder. In the latter case, there is an advantage that even the stator core 31 having a complicated shape can be manufactured relatively easily.

The teeth 32 are arranged at the same position with respect to the circumferential direction of the yoke 34 on one end face side and the other end face side of the yoke 34. The teeth 32 have a flat plate portion 32P facing the magnet 13 of the first rotor 10 and the magnet 23 of the second rotor 20, and a shaft portion 32S connecting the flat plate portion 32P and the yoke 34. A plurality of teeth 32 are arranged on both end faces of the yoke 34, and the teeth 32 on the end face sides face the first rotor 10 and the second rotor 20.

A slot 35 is formed between adjacent teeth 32 in the circumferential direction of the yoke 34. In the present embodiment, since the plurality of teeth 32 are arranged on both end faces of the yoke 34, the slots 35 are also formed on one end face side and the other end face side. In the present embodiment, the number of slots 35 is counted as two slots 35 formed on both end face sides of the yoke 34. The number of slots 35 is equal to the number of teeth 32 provided on one end face side or the other end face side. In the present embodiment, the number of slots 35 included in the stator 30 is 3 × n.

A winding 33 is disposed in each slot 35. The winding 33u indicates the U phase, the winding 33v indicates the V phase, and the winding 33w indicates the W phase. The winding 33 is wound around the yoke 34 in the slot 35 portion in the circumferential direction of the yoke 34. Thus, in the present embodiment, the winding 33 is wound around the yoke 34 in a toroidal shape to form a toroidal coil. By doing in this way, a magnetic circuit can be independently formed in the 1st rotor 10 side and the 2nd rotor 20 side, respectively. As a result, the first rotor 10 and the second rotor 20 can be driven independently, and a decrease in output can be suppressed.

The stator core 31 can be manufactured, for example, by putting magnetic powder into a mold and then compression-molding, but the manufacturing method of the stator core 31 is not limited to this. In the stator 30, a stator core 31 in which the winding 33 is wound around the yoke 34 may be molded with resin. By doing in this way, since the stator core 31 and the coil | winding 33 can be united, the handling of the stator 30 becomes easy.

<Modified example of electric motor>
FIG. 6 is a cross-sectional view of an electric motor according to a modification of the present embodiment cut along a plane that passes through the rotation axis and includes the rotation axis. FIG. 7 is a partial cross-sectional view of the electric motor according to the present embodiment cut along a plane orthogonal to the rotation axis. The electric motor 1a is common to the above-described electric motor 1 (see FIG. 1 and the like) in that the first rotor 10a and the second rotor 20a are driven by a common stator 30a. The type of the electric motor 1 described above is an axial gap type, whereas the type of the electric motor 1a is a gap between the first rotor 10 and the second rotor 20 and the stator 30 in the direction orthogonal to the rotation axis Zr, that is, in the radial direction. The difference is that it is a radial gap type. That is, in the electric motor 1a, the stator 30a is disposed on the radially outer side of the first rotor 10, and the second rotor 20a is disposed on the radially outer side of the stator 30a.

The electric motor 1a includes a first rotor 10a, a second rotor 20a, and a stator 30a. The electric motor 1 is a three-phase electric motor, and the first rotor 10 and the second rotor 20 are driven by a common stator 30. In the electric motor 1a, the end 31T of the stator core 31a of the stator 30a in the direction of the rotation axis Zr is fixed to the attachment target 4. The first rotor 10a and the second rotor 20a rotate around a common rotation axis Zr. The second rotor 20a is disposed on the radially outer side of the first rotor 10a and on the radially outer side of the stator 30a. With such a structure, the stator 30a is disposed between the first rotor 10a and the second rotor 20a. Therefore, the first rotor 10a, the stator 30a, and the second rotor 20a are arranged on three concentric circles having different diameters around the rotation axis Zr.

The first rotor 10a includes a rotor body (yoke) 11a as a cylindrical structure, a power transmission shaft 12a attached to the rotor body 11a, and a plurality of magnets (permanent magnets) 13a attached to the rotor body 11a. Have. The second rotor 20a includes a rotor body (yoke) 21a as a cylindrical structure, a power transmission shaft 22a attached to the rotor body 21a, and a plurality of magnets (permanent magnets) 23a attached to the rotor body 21a. Have. The

power transmission shafts

12a and 22a respectively extend from one end face of the rotor

main bodies

11a and 21a in the direction of the rotation axis Zr. The extending directions of the power transmission shaft 12a of the first rotor 10a and the power transmission shaft 22a of the second rotor 20a are opposite to each other. The central axes of the

power transmission shafts

12a and 22a are the same as the central axes of the

rotor bodies

11a and 21a. These are also common to the rotation axis Zr of the electric motor 1a.

The stator 30a is an annular structure. The stator 30a includes a stator core 31a, teeth 32ao and 32ai provided on the stator core 31a, and windings (coils) 33a wound around the stator core 31a. The winding 33a is a conductor and is the same as the electric motor 1 described above. The dotted line in FIG. 7 shows how to wind the winding wire 33a. The stator core 31a has through holes 31HA and 31HB in the center.

7, the stator core 31a of the stator 30a has an annular yoke 34a and a plurality of teeth 32ao and 32ai provided on the outer peripheral surface and the inner peripheral surface of the yoke 34a, respectively. The material of the stator core 31a is the same as that of the stator core 31 described above. On the outer peripheral surface and inner peripheral surface of the yoke 34a, the teeth 32ao and 32ai are arranged at the same position with respect to the circumferential direction of the yoke 34a. The teeth (second teeth) 32ao arranged on the outer peripheral surface of the yoke 34a face the second rotor 20a, more specifically, the magnet 23a provided on the inner peripheral surface of the second rotor 20a. The teeth (first teeth) 32ai disposed on the inner peripheral surface of the yoke 34a face the first rotor 10a, more specifically, the magnet 13a provided on the outer peripheral surface of the first rotor 10a.

The slot 35a is between the teeth 32ao and 32io adjacent in the circumferential direction of the yoke 34a. In the present embodiment, since the plurality of teeth 32ai and 32ao are arranged on the inner peripheral surface and the outer peripheral surface of the yoke 34a, the slot 35a is also formed on the inner peripheral surface side and the outer peripheral surface side. In this modification, the number of slots 35a is counted as two slots 35a formed on the inner and outer peripheral surfaces of the yoke 34a. The number of slots 35a is equal to the number of teeth 32ai and 32ao provided on the inner and outer peripheral surfaces of the yoke 34a, respectively. Also in this modification, the number of slots 35a included in the stator 30a is 3 × n. A winding 33a is disposed in each slot 35a. The winding 33 au indicates the U phase, the winding 33 av indicates the V phase, and the winding 33 aw indicates the W phase. The winding 33a is wound around the yoke 34a at the slot 35a in the circumferential direction of the yoke 34a. Thus, also in this modification, the winding wire 33a is wound around the yoke 34a in a toroidal shape to form a toroidal coil.

The power transmission shaft 12a of the first rotor 10a is supported by bearings 3Aa and 3Ba. As for the 2nd rotor 20a, bearing 3Ca, 3Da is attached to the internal peripheral surface of the both ends in the rotating shaft Zr direction. The bearings 3Aa and 3Ba that support the first rotor 10a are attached to the two through holes 31HA and 31HB of the stator core 31a of the stator 30a. The bearings 3Ca and 3Da that support the second rotor 20a are attached to the outer peripheral portions of both end portions of the stator 30a in the rotation axis Zr direction. With such a structure, the first rotor 10a and the second rotor 20a are rotatably supported by the stator 30a via the bearings 3Aa, 3Ba, 3Ca, 3Da. Further, the first rotor 10a and the second rotor 20a can rotate independently of the stator 30a.

The power transmission shaft 12a of the first rotor 10a is taken out of the electric motor 1a from the two through holes 31HB of the stator core 31a. The power transmission shaft 22a of the second rotor 20a is attached to the end surface of the second rotor 20a on the side opposite to the power transmission shaft 12a of the first rotor 10a. Since the stator 30a is attached to the attachment object 4, it is stationary. In the electric motor 1a, the first rotor 10a rotates independently of the inner side of the stator 30a and the second rotor 20a rotates independently of the outer side of the stator 30a by a rotating magnetic field generated by the stator 30a.

6 and 7, the plurality of magnets 13a included in the first rotor 10a are provided on the outer peripheral surface of the rotor main body 11a or embedded on the outer peripheral surface side of the rotor main body 11a. In the plurality of magnets 13a, north and south poles are alternately arranged in the circumferential direction of the rotor body 11a. The plurality of magnets 23a included in the second rotor 20 are provided on the inner peripheral surface of the rotor main body 21a or embedded on the inner peripheral surface side of the rotor main body 21a. In the plurality of magnets 23a, north and south poles are alternately arranged in the circumferential direction of the rotor body 21a. In the present embodiment, the magnets 13Na and 23Na represent the N pole, and the magnets 13Sa and 23Sa represent the S pole.

Magnets

13a and 23a create magnetic poles. The number of

magnets

13 a and 23 a is the same as that of the electric motor 1.

<Setting the number of poles>
FIG. 8 is a schematic diagram showing the relationship between the electrical angle and phase of the three-phase motor. FIG. 9 is a schematic diagram showing the phase order of the comparative example. FIG. 10 is a schematic diagram showing the phase sequence of the present embodiment. In the following, the axial type electric motor 1 shown in FIG. 1 and the like is taken as an example, but the same applies to the radial type electric motor 1a shown in FIG. 6 and the like. In the electric motor 1 which is a three-phase electric motor, the electrical angle θe (°) is expressed by the equation (1), where P is the number of magnetic poles (number of poles) and S is the number of slots (number of slots).
θe = 180 × P / S (1)

The winding 33 of the electric motor 1 has a U phase, a V phase, and a W phase. Voltages having different phases are applied to the U-phase winding 33u, the V-phase winding 33v, and the W-phase winding 33w, respectively. Accordingly, currents having different phases flow through the

respective windings

33u, 33v, and 33w. As shown in FIG. 8, when the electrical angle θe is 0 ° or more and less than 60 °, the + U phase, and when the electrical angle θe is 60 ° or more and less than 120 °, the −W phase and the electrical angle θe is 120 ° or more and 180 °. When the angle is less than °, the + V phase, when the electrical angle θe is 180 ° or more and less than 240 °, the −U phase, when the electrical angle θe is 240 ° or more and less than 300 °, the + W phase, and the electrical angle θe is 300 ° When the angle is less than 360 °, the phase is −V. “+” And “−” attached to symbols indicating the respective phases indicate the directions of currents flowing through the U phase, the V phase, and the W phase. By giving a three-phase alternating current in the order of the phases, a rotating magnetic field necessary for the rotation of the electric motor 1 can be obtained.

As a comparative example, the stator 30 of the electric motor 1 has twelve slots 35A to 35L (the number of slots S = 12), and the first rotor 10 has four N-pole magnets 13N and four S-pole magnets 13S. It is assumed that the second rotor 20 has five N-pole magnets 23N and five S-pole magnets 23S (pole number P = 10). In this case, the electrical angle θe of the first rotor 10 changes 120 ° between the

adjacent slots

35A and 35B, and the electrical angle θe of the second rotor 20 changes 150 ° between the

adjacent slots

35A and 35B. .

As shown in FIG. 9, in the comparative example, since the electrical angle θe of the first rotor 10 and the electrical angle θe of the second rotor 20 are both 0 ° in the slot 35A, the phases of the windings 33 are both + U phases. It is the same phase. In the slot 35B, the electrical angle θe of the first rotor 10 is 120 degrees and the + V phase, and the electrical angle θe of the second rotor 20 is 150 °. Therefore, the phases of the windings 33 are both the + V phase and the same phase. However, since the electrical angle θe of the first rotor 10 is 240 ° in the slot 35C, the phase of the winding 33 is + W phase, whereas the electrical angle θe of the second rotor 20 is 300 °, so the phase of the winding 33 is − V phase and different phase. Regarding the slots 35D to 35L, the phase of the winding 33 in the first rotor 10 and the phase of the winding 33 in the second rotor 20 are different. For this reason, the first rotor 10 and the second rotor 20 cannot be independently driven and controlled by the relationship between the number of poles P and the number of slots S as in the comparative example.

In the present embodiment, the stator 30 of the electric motor 1 has twelve slots 35A to 35L (the number of slots S = 12), and the first rotor 10 has four N-pole magnets 13N and four S-pole magnets 13S. Consider the case where the number of poles is P (number of poles P = 8), and the second rotor 20 has eight

magnets

23N and 23S of poles N (number of poles P = 16). In this case, the electrical angle θe of the first rotor 10 changes by 120 ° between the

adjacent slots

35A and 35B. In the second rotor 20, the electrical angle θe changes by 240 ° between the

adjacent slots

35A and 35B.

As shown in FIG. 10, in the present embodiment, when the first rotor 10 and the second rotor 20 are driven by a common stator 30, the winding 33 is formed by the first rotor 10 and the second rotor 20 in the slot 35 A. The phase order is reversed. In this state, when a current in phase between the first rotor 10 and the second rotor 20 is applied to the winding 33 of the slot 35A, the first rotor 10 and the second rotor 20 are rotated in opposite directions. Further, the phase of the current for driving the second rotor 20 (or the first rotor 10) is advanced by 180 °, and the V phase and the W phase of the second rotor 20 (or the first rotor 10) are switched. In this way, the phase sequence of the windings 33 can be made the same in the first rotor 10 and the second rotor 20 in the slot 35A, so that the first rotor 10 and the second rotor 20 rotate in the same direction. Can be made. With the relationship between the number of poles P and the number of slots S as in this embodiment, the first rotor 10 and the second rotor 20 can be driven and controlled independently.

For this reason, in the present embodiment, m and n in the formula 2 × m + 6 × n × (k−1) are fixed, and a group of even numbers obtained by changing k, and 3 × n / 2. A group including multiple and the smallest even number and the smallest even multiple is excluded, and m is changed from a small value to a large value, and the (j + 1) th group and (2 × ij) Two even numbers each selected from the first group are the numbers of magnetic poles of the first rotor 10 and the second rotor 20, respectively. That is, two even numbers selected as the number of magnetic poles of the first rotor 10 and the second rotor 20 are a plurality of numbers included in the (j + 1) th group from the smaller m in the 2 × i group described above. And even one of a plurality of even numbers included in the (2 × ij) -th group from the smaller m. Here, i, m, n, and k are integers of 1 or more, j is an integer of 0 to i−1, and the maximum value of m is 3 × n−1.

Suppose, for example, that 8 groups are obtained when n is fixed and m is changed from a small value to a large value. Since 2 × i = 8, i becomes 4. When j = 0, one even number is selected from each of the first group and the eighth group from the smallest m, that is, the smallest group and the largest group. When j = 1, one even number is selected from the second group and the seventh group from the smaller m, that is, one from the second smallest group and the second largest group. By setting the number of poles P and the number of slots S (= 3 × n) in this way, the phase order of the windings 33 can be reversed between the first rotor 10 and the second rotor 20 in the slot 35A. . Therefore, as described above, the first rotor 10 and the second rotor 20 can be independently driven and controlled by controlling the phase of the three-phase current.

When n = 1, the number of slots S = 3 × n = 3. The group consisting of even numbers obtained from 2 × m + 6 × n × (k−1) is as follows. The number attached to the end of each group is the group number (the same applies hereinafter). The maximum value of m is 3 × n−1 = 2. A multiple of 3 × n / 2 and the smallest even number is 6, but when n = 1, there is no group in which m is 3 or more, so there is no group that starts with an even number of 6 or more.
m = 1: (2, 8, 14, 20...): 1
m = 2: (4, 10, 16, 22 ...): 2

Since the number 2 × i of groups obtained by changing m is 2, i = 1 and the maximum value of j is 0. In this case, one even number is selected from each of the first group and the second group as the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20. Therefore, combinations that can be selected as the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 include 2 and 4, 8, and 10, 14 and 16, and the like.

When n = 2, the number of slots S = 3 × n = 6. A group of numbers obtained from 2 × m + 6 × n × (k−1) is as follows. The maximum value of m is 3 × n−1 = 5. A multiple of 3 × n / 2 and the smallest even number is 6. The group when m = 3 is (6, 18, 30, 42...), and 6 is included in the minimum number. For this reason, the group of m = 3 is excluded from selection of the pole numbers P1 and P2. This is because in the case of n = 2, if m = 3, the phase of the winding 33 forms a group including an even number lacking at least one of the U phase, the V phase, and the W phase. For this reason, when n = 2, m = 3 is excluded.
m = 1: (2, 14, 26, 38...): 1
m = 2: (4, 16, 28, 40 ...): 2
m = 4: (8, 20, 32, 44...): 3
m = 5: (10, 22, 34, 46...): 4

Since the number of groups 2 × i obtained by changing m is 4, i = 2, and the maximum value of j is 1. In this case, the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 are one each from the first group and the fourth group, respectively from the even number or the second group and the third group. One even number is selected. Therefore, combinations that can be selected as the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 include 2 and 10, 14 and 22 when j = 0, and 4 and 8 when j = 1. 16 and 20 etc.

When n = 3, the number of slots S = 3 × n = 9. A group of numbers obtained from 2 × m + 6 × n × (k−1) is as follows. The maximum value of m is 3 × n−1 = 8. A multiple of 3 × n / 2 and the smallest even number is 18, but when n = 3, there is no group starting with an even number greater than or equal to 18 because there is no group with m equal to or greater than 9.
m = 1: (2, 20, 38, 56, 74...): 1
m = 2: (4, 22, 40, 58, 76 ...): 2
m = 3: (6, 24, 42, 60, 78 ...): 3
m = 4: (8, 26, 44, 62, 80 ...): 4
m = 5: (10, 28, 46, 64, 82...): 5
m = 6: (12, 30, 48, 66, 84...): 6
m = 7: (14, 32, 50, 68, 86...): 7
m = 8: (16, 34, 52, 70, 88 ...): 8

Since the number of groups 2 × i obtained by changing m is 8, i = 4 and the maximum value of j is 3. In this case, the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 are respectively an even number, one each from the first group and the eighth group, respectively from the second group and the seventh group. One even number is selected from each of the third group, and the sixth group, and one even number is selected from each of the fourth group and the fifth group. Therefore, combinations that can be selected as the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 include 2 and 16, 20 and 34 when j = 0, and 4 and 14 when j = 1. , 20 and 32, etc., and when j = 2, there are 6 and 12, 24 and 30, etc., and when j = 3, there are 8 and 10, 26 and 28 etc.

When n = 4, the number of slots S = 3 × n = 12. A group of numbers obtained from 2 × m + 6 × n × (k−1) is as follows. The maximum value of m is 3 × n−1 = 11. The multiple of 3 × n / 2 and the smallest even number is 6, and the multiples are 12, 18. The group when m = 3 is (6, 30, 54, 78, 102...), and 6 is included in the minimum number. The group when m = 6 is (12, 36, 60, 84, 108...), and 12 is included in the minimum number. The group when m = 9 is (18, 42, 66, 90, 114...), and 18 is included in the minimum number. For this reason, the group of m = 3, 6, and 9 is excluded from selection of the pole numbers P1 and P2. This is because when n = 4 and m = 3, 6, and 9, a group including an even number in which the phase of the winding 33 lacks at least one of the U phase, the V phase, and the W phase is formed.
m = 1: (2, 26, 50, 74, 98...): 1
m = 2: (4, 28, 52, 76, 100 ...): 2
m = 4: (8, 32, 56, 80, 104 ...): 3
m = 5: (10, 34, 58, 82, 106...): 4
m = 7: (14, 38, 62, 86, 110 ...): 5
m = 8: (16, 40, 64, 88, 112 ...): 6
m = 10: (20, 44, 68, 92, 116 ...): 7
m = 11: (22, 46, 70, 94, 118 ...): 8
Since the number of groups 2 × i obtained by changing m is 8 as in the case of n = 3, i = 4 and j becomes 3. In this case, the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 are respectively an even number, one each from the first group and the eighth group, respectively from the second group and the seventh group. One even number is selected from each of the third group, and the sixth group, and one even number is selected from each of the fourth group and the fifth group. Therefore, combinations that can be selected as the number of poles P1 of the first rotor 10 and the number of poles P2 of the second rotor 20 include 2 and 22, 26, and 46 when j = 0, and 4 and 20 when j = 1. , 28 and 44, etc., and when j = 2, there are 8 and 16, 32 and 40, etc., and when j = 3, there are 10 and 14, 34 and 38 etc. Next, control of the electric motor 1 according to the present embodiment will be described. This control may be the example shown in FIG. 10, that is, the number of slots S = 12, the number of poles P of the first rotor 10 is 8, and the number of poles P of the second rotor 20 is P = 16. The number of slots S may be 12, the number of poles P of the first rotor 10 may be 10, and the number of poles P of the second rotor 20 may be 14. That is, the control of the electric motor 1 according to the present embodiment can be applied to the electric motor 1 having the number of slots, the number of poles of the first rotor 10 and the number of poles of the second rotor 20 determined as described above.

The number of magnetic poles of the first rotor 10 and the second rotor 20 can be expressed as follows. That is, a group consisting of an even number obtained by fixing m and n in Formula 2 × m + 6 × n × (k−1) and changing k, which is a multiple of 3 × n / 2 and the smallest even number and Two even numbers, each selected from the group of m and the group of 3 × n−m, excluding the group including the smallest even multiple, are respectively the magnetic poles of the first rotor 10 and the second rotor 20. It is a number. That is, two even numbers selected as the number of magnetic poles of the first rotor 10 and the second rotor 20 are included in one of a plurality of even numbers included in the m group and in a 3 × n−m group. One of a plurality of even numbers. Here, m, n, and k are integers of 1 or more, and the maximum value of m is 3 × n−1. The reason why the group including a multiple of 3 × n / 2, the smallest even number, and the smallest even multiple is excluded is to exclude combinations in which the winding phase order is not three phases.

For example, when n = 4, m is 1, 2, 4, 5, 7, 8, 10, 11. In this case, the number of magnetic poles of the first rotor 10 and the second rotor 20 is two even numbers each selected from the group of m = 1 and the group of m = 3 × 4-1 = 11. When m = 2, two even numbers each selected from the group of m = 2 and the group of m = 3 × 4-2 = 10 are respectively selected. When m = 4, the group of m = 4 and m = 2 × 4−4 = 8, each of which is an even number selected from the group of m = 5, and when m = 5, each of m = 5 and m = 3 × 4−5 = 7 Two even numbers selected one by one are the number of magnetic poles of the first rotor 10 and the second rotor 20.

<Control of electric motor>
When the combination of the number of poles P and the number of slots S is as described above, the first rotor 10 and the second rotor 20 are in a winding phase sequence that rotates in opposite directions. For this reason, first, the case where the 1st rotor 10 and the 2nd rotor 20 are rotated in the mutually opposite direction is demonstrated. In the electric motor 1, the first rotor 10 and the second rotor 20 are driven by a common stator 30. Therefore, the current (drive current) applied to the

windings

33u, 33v, 33w of the stator 30 is the current (or voltage, the same applies hereinafter) for driving the first rotor 10, and the current for driving the second rotor 20. It becomes a current (composite current) obtained by superimposing (superimposing) the current. The rotational speed of the first rotor 10 is ω1 / π × 30 rpm, the current amplitude for driving the first rotor 10 is I1 (ampere), the rotational speed of the second rotor 20 is ω2 / π × 30 rpm, and the second rotor 20 Suppose that the amplitude of the current for driving is I2 (ampere), and the currents of the U phase, V phase, and W phase are changed by sin waves. When the first rotor 10 and the second rotor 20 are rotated in the same direction, the U-phase, V-phase, and W-phase drive currents U1, V1, and W1 of the first rotor 10 are expressed by equations (2) to (4). Thus, the drive currents U2, V2, and W2 of the second rotor 10 for the U-phase, V-phase, and W-phase are expressed by equations (5) to (7). ω1 and ω2 are angular frequencies of the first rotor 10 and the second rotor 20, respectively, and t is time.

U1 = I1 × sin (ω1 × t) (2)
V1 = I1 × sin (ω1 × t−2 × π / 3) (3)
W1 = I1 × sin (ω1 × t + 2 × π / 3) (4)
U2 = I2 × sin (ω2 × t) (5)
V2 = I2 × sin (ω2 × t−2 × π / 3) (6)
W2 = I2 × sin (ω2 × t + 2 × π / 3) (7)

The driving currents of the U phase, the V phase, and the W phase are values obtained by adding the currents of the respective phases of the first rotor 10 and the currents of the respective phases of the second rotor 20. That is, the U-phase drive current U, that is, the drive current of the winding 33u is expressed by Equation (8), the V-phase drive current V, that is, the drive current of the winding 33v is expressed by Equation (9), and the W-phase drive current W That is, the drive current of the winding 33w is as shown in Expression (10). The control device for the electric motor 1 generates drive currents U, V, and W expressed by the equations (8) to (10) and supplies them to the

windings

33u, 33v, and 33w of the stator 30 that the electric motor 1 has. One first rotor 10 and second rotor 20 can be driven independently. For example, the rotational speed of the first rotor 10 and the line speed of the second rotor 20 can be made different by making the angular frequencies ω1 and ω2 different. Also, by making the current amplitude I1 for driving the first rotor 10 or the current amplitude I2 for driving the second rotor 20 different, the output of the first rotor 10 and the output of the second rotor 20 are obtained. Can be different.
U = U1 + U2 (8)
V = V1 + V2 (9)
W = W1 + W2 (10)

Next, a case where the first rotor 10 and the second rotor 20 are rotated in the same direction will be described. In this case, the V phase and the W phase of either the first rotor 10 or the second rotor 20 are exchanged and the phase of the current flowing through each phase is advanced by 180 ° with respect to the case where both are rotated in the opposite direction. Make it.

When the first rotor 10 and the second rotor 20 are rotated in the same direction, the U-phase, V-phase, and W-phase drive currents U1, V1, and W1 of the first rotor 10 are expressed by the equations (2) to ( 4), and the U-phase, V-phase, and W-phase drive currents U2, V2, and W2 of the second rotor 10 are expressed by equations (11) to (13). The U phase of the second rotor 20 is obtained by adding 180 °, that is, π to the equation (5). The V phase of the second rotor 20 advances the phase of Equation (5) by (2 × π / 3 + π), and the W phase of the second rotor 20 advances the phase of Equation (5) by (−2 × π / 3 + π). It has been advanced. By giving U1, V1, W1 of the equations (2) to (3) and U2, V2, W2 of the equations (11) to (13) to the equations (8) to (10), the first rotor 10 And U-phase, V-phase, and W-phase drive currents U, V, and W when the second rotor 20 and the second rotor 20 are rotated in the same direction.
U2 = I2 × sin (ω2 × t + π) (11)
V2 = I2 × sin (ω2 × t + 2 × π / 3 + π) = I1 × sin (ω2 × t + 5 × π / 3) (12)
W2 = I2 × sin (ω2 × t−2 × π / 3 + π) = I1 × sin (ω2 × t + π / 3) (13)

Thus, the electric motor 1 (same for the electric motor 1a) has the number of poles P and the number of slots S so that the electrical angle θe between adjacent slots is the same in both the first rotor 10 and the second rotor 20. Set. Then, a combined current obtained by superimposing the current for driving the first rotor 10 and the current for driving the second rotor 20 is applied to the winding 33 of the stator 30. By doing in this way, the electric motor 1 can control the 1st rotor 10 and the 2nd rotor 20 independently. Specifically, the electric motor 1 can independently control the rotation direction, the rotation speed, and the torque of the first rotor 10 and the second rotor 20. Therefore, the first rotor 10 and the second rotor 20 can rotate in the same direction or in opposite directions.

The current for driving the first rotor 10 and the current for driving the second rotor 20 have a frequency corresponding to the rotational speed and an amplitude corresponding to the torque. The electric motor 1 can drive and control the first rotor 10 and the second rotor 20 independently by setting the number of poles P and the number of slots S to the relationship described above. For this reason, the current for driving the first rotor 10 and the current for driving the second rotor 20 have different frequencies and amplitudes, thereby rotating the first rotor 10 and the second rotor 20. The speed and torque can be controlled to different magnitudes.

In the electric motor 1, since the first rotor 10 and the second rotor 20 can be controlled independently, it is possible to individually set and control a transitional time from starting up to a constant rotational speed. . That is, the electric motor 1 can be set differently between the first rotor 10 and the second rotor 20 from the time it is activated until it reaches a certain rotational speed.

<Modification of stator>
FIG. 11 is a perspective view showing a modification of the stator. FIG. 12 is a partial plan view showing a modification of the stator. When the electric motor 1 is an axial gap type, the first rotor 10 and the second rotor 20 are arranged in a direction parallel to the rotation axis Zr. When the electric motor 1 is an axial gap type, as shown in FIG. 12, in the stator, more specifically, the stator core 31D, the slot 35 may have the same shape between the radially outer side and the radially inner side. preferable.

In the present modification, the stator core 31D includes the length of the arc portion (outer arc) on the radially outer side of the slot 35, that is, the length Lout of the outer arc between the shaft portions 32DS of the adjacent teeth 32D, and the slot The length of the arc portion (inner circumference arc) on the radially inner side of the portion 35, that is, the length Lin of the inner circumference arc between the shaft portions 32DS of the adjacent teeth 32D, is preferably the same size, preferably the same. It has become. For this purpose, the length tout of the arc portion on the radially outer side of the shaft portion 32DS of the tooth 32 is larger than the length tin of the arc portion on the radially inner side of the shaft portion 32DS of the tooth 32.

By doing in this way, the slot 35 formed between the shaft parts 32DS of the adjacent teeth 32 can make the dimension of the stator core 31D in the circumferential direction substantially constant toward the radial direction of the stator core 31D. . As a result, more windings 33 can be wound around the slots 35, and the winding 33 can be easily wound around the stator core 31D.

DESCRIPTION OF

SYMBOLS

1, 1a Electric motor 2 Housing | casing 2I Inner

peripheral part

3A, 3B, 3C, 3D, 3Aa, 3Ba, 3Ca, 3Da Bearing 4

Attachment object

5, 6 Through-

hole

10, 10a, 10I 1st rotor 10T 1st

magnet engaging part

11, 11a, 11b, 11c, 11I, 21, 21a, 21b, 21c,

21I Rotor body

12, 12a, 22, 22a

Power transmission shaft

13, 13a, 13I, 23, 23a,

23I Magnet

20, 20a, 20I Second Rotor 20T 2nd

magnet engaging part

30,

30a Stator

31, 31a, 31A, 31B, 31C, 31D, 31E, 31F Stator core 31H, 31HA, 31HB Through-hole 31T End part 32, 32ao, 32ai, 32C, 32D, 32E , 32F, 32G, 32H Teeth 32S, 32DS Shaft 32P, 32EP,

32Pg Plate portion

33,33u, 33v, 33w, 33a, 33au, 33av,

33aw windings

34, 34a,

34C yoke

35, 35a, 35A ~ 35L slot

Claims

A first rotor and a second rotor rotating about a rotation axis;
A ring-shaped structure that is disposed between the first rotor and the second rotor and surrounds the periphery of the rotation shaft, and a stator having 3 × n slots;
A plurality of windings disposed in each of the slots,
A group consisting of an even number obtained by fixing m and n in the formula 2 × m + 6 × n × (k−1) and changing k, which is a multiple of 3 × n / 2, the smallest even number, and the minimum From the (j + 1) th group and the (2 × i−j) th group in the 2 × i groups obtained by changing m from a small value to a large value. Two even numbers each selected one by one are the number of magnetic poles of the first rotor and the second rotor, respectively.
Here, i, m, n, and k are integers of 1 or more, j is an integer of 0 to i−1, and the maximum value of m is 3 × n−1.
The electric motor according to claim 1, wherein a current obtained by superimposing a current for driving the first rotor and a current for driving the second rotor is applied to the winding of the stator.
3. The electric motor according to claim 2, wherein the current for driving the first rotor and the current for driving the second rotor are currents having different frequencies and amplitudes.
The electric motor according to any one of claims 1 to 3, wherein the winding is a toroidal coil wound in a circumferential direction of the stator.
The first rotor has a portion that engages with a magnet for making the magnetic pole of the first rotor radially outward, and the second rotor is for making the magnetic pole of the second rotor radially outward. The electric motor of any one of Claim 1 to 4 which has a part engaged with a magnet.
The electric motor according to any one of claims 1 to 5, wherein the first rotor and the second rotor are arranged in parallel to each other from the front of the rotating shaft to the back with the stator interposed therebetween.
The electric motor according to claim 6, wherein the stator has the same outer circumferential arc length and inner circumferential arc length in the slot portion between the radially outer side and the radially inner side.
A first rotor and a second rotor that rotate about a rotation axis and that have a magnet that forms a magnetic pole and a portion that engages with the magnet on a radially outer side;
A ring-shaped structure that is disposed between the first rotor and the second rotor and surrounds the periphery of the rotation shaft, and a stator having 3 × n slots;
A plurality of windings that are disposed in each of the slots and become toroidal coils wound in the circumferential direction of the stator,
The first rotor and the second rotor are arranged in parallel to each other from the front of the rotating shaft to the back with the stator interposed therebetween,
Furthermore, a group consisting of an even number obtained by fixing m and n in Formula 2 × m + 6 × n × (k−1) and changing k, which is a multiple of 3 × n / 2 and the smallest even number and The group including the smallest even multiple is excluded, and the (j + 1) -th group and the (2 × ij) -th group in 2 × i groups obtained by changing m from a small value to a large value Two even numbers selected one by one from the group respectively become the number of magnetic poles of the first rotor and the second rotor, respectively.
Here, i, m, n, and k are integers of 1 or more, j is an integer of 0 to i−1, and the maximum value of m is 3 × n−1.