JP2006020442A - Rotor structure of axial-gap rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor structure of an axial-gap rotating electric machine wherein eddy currents generated in permanent magnets can be reduced to reduce heat generation and a rotating electric machine can be rotated at high speed. <P>SOLUTION: An axial-gap rotating electric machine 1 includes a rotor 3 having a rotor core 7 and permanent magnets 8; and a stator 4 having stator teeths 11 and stator coils 10 wound around the stator teeths 11. The rotating electric machine 1 is so constructed that the rotor 3 and the stator 4 are disposed in the axial direction. With respect to its rotor structure, a magnet 8 corresponding to one pole of the permanent magnets is so constructed that it is divided in the circumferential direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a rotor having a rotor core and a permanent magnet, a stator having a stator teeth portion and a stator coil wound around the stator teeth portion, and the rotor and the The present invention relates to a rotor structure of an axial gap type rotating electrical machine in which a stator is disposed in an axial direction.

Many rotating electrical machines in which a permanent magnet is embedded in a rotor are used for reasons such as low loss, high efficiency, and high output. Among them, the axial gap type rotating electrical machine in which the rotor and the stator are arranged in the axial direction can be reduced in thickness and is used for applications where the layout is limited. However, if an attempt is made to increase the rotation speed with an axial gap type rotating electrical machine, the magnet is disposed on the surface of the rotor, so that an eddy current is generated inside the magnet, which may generate heat and cause permanent demagnetization. Is expensive. Therefore, in the technique described in Patent Document 1 below, a permanent magnet per pole is composed of a plurality of cylindrical permanent magnets.
Japanese Patent No. 3207251

  FIG. 8 is a diagram showing a cross section in the radial direction of the above-described conventional axial gap type rotating electric machine. In the conventional example shown in FIG. 8, the permanent magnet 51 per pole is composed of a plurality of cylindrical permanent magnets 52. Here, the rotor 53 does not use a ferromagnetic material, and a permanent magnet is held by the resin 54. By forming the permanent magnet 51 per pole by the plurality of permanent magnets 52, heat generation can be reduced by reducing the eddy current generated in the permanent magnet, and the rotating electrical machine can be rotated at a high speed. However, by forming the rotor 53 with a permanent magnet and resin, the generated torque is reduced because the magnetic resistance in the rotor 53 is large and the reluctance torque cannot be obtained because there is no magnetic material. On the other hand, when a ferromagnetic material such as a dust core is used instead of the resin 54, a leakage magnetic flux is generated between the magnets, and the generated torque is also reduced. Further, there is a problem in that the permanent magnet 52 is fixed by the resin 54, which makes it difficult to manufacture.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, reduce the eddy current generated in the permanent magnet, reduce heat generation, and increase the rotational speed of the rotating electrical machine. It is intended to provide a structure.

  The rotor structure of the axial gap type rotating electric machine of the present invention includes a rotor having a rotor core and a permanent magnet, a stator having a stator teeth portion and a stator coil wound around the stator teeth portion, In the rotor structure of an axial gap type rotating electrical machine in which the rotor and the stator are arranged in the axial direction, the permanent magnet per pole among the permanent magnets is divided in the circumferential direction. To do.

  According to the rotor structure of the axial gap type rotating electrical machine of the present invention, in the axial gap type rotating electrical machine in which the rotor and the stator are arranged in the axial direction, the permanent magnet per pole is divided in the circumferential direction, thereby The internal eddy current can be reduced, the amount of heat generation is reduced, and high-speed rotation is enabled. In addition, since the rotor is composed of a ferromagnetic material and a permanent magnet, the magnetic resistance in the rotor is small and the reluctance torque can be obtained, so that the generated torque can be increased.

  In addition, as a suitable example of the rotor structure of the axial gap type rotating electrical machine of the present invention, there is a case where the permanent magnet per pole is finely divided at the end and roughly at the center. If configured in this way, the method of dividing the permanent magnet per pole can reduce the heat generation amount with fewer divisions by making the end portion finer and the center portion rougher, thereby reducing the cost. is there.

  Further, as a preferred example of the rotor structure of the axial gap type rotating electrical machine of the present invention, the division of the end portion of the permanent magnet per pole may be a combination of substantially rectangular shapes. If comprised in this way, the division | segmentation of the edge part of the permanent magnet per pole is comprised by combining several permanent magnets of the substantially same shape of a rectangle, and a magnet is comprised, without increasing the kind of magnet shape. And the cost can be reduced.

  Furthermore, as a suitable example of the rotor structure of the axial gap type rotating electric machine of the present invention, the permanent magnet per pole is composed of two types of shapes having a substantially rectangular end portion and a central portion having one shape. May be configured. If constituted in this way, the division of the end portion of the permanent magnet per pole is configured by combining a plurality of substantially rectangular permanent magnets, and the central permanent magnet is made into one shape, Permanent magnets per pole can be configured with two types of magnet shapes, and costs can be reduced.

  Furthermore, as a suitable example of the rotor structure of the axial gap type rotating electrical machine of the present invention, the magnet shape of the central portion of the permanent magnet per pole may be substantially a sector shape. If comprised in this way, the division | segmentation of the edge part of the permanent magnet per pole is comprised combining several permanent magnets of the substantially rectangular same shape, and making the permanent magnet of a center part into a substantially sector shape. In addition, two types of magnet shapes can be used to form a substantially sector-shaped magnet, and magnets per pole can be easily formed, so that the cost can be reduced.

  In addition, as a preferred example of the rotor structure of the axial gap type rotating electrical machine of the present invention, the permanent magnet per pole can determine the magnet shape per pole by changing the magnet shape at the center. is there. If comprised in this way, the division | segmentation of the edge part of the permanent magnet per pole will comprise a plurality of substantially rectangular same-shaped permanent magnets, and the central permanent magnet may be, for example, a parallelogram. In this case, the shape of the permanent magnet per pole is changed to a substantially parallelogram, and the permanent magnet at the center is changed by changing the angle of the side in the circumferential direction. It is possible to easily form a magnet shape per one pole depending on the shape of the magnet at the center, such as being able to reduce the cost, so that the cost can be reduced.

  Furthermore, as a preferred example of the rotor structure of the axial gap type rotating electrical machine of the present invention, there is a shape in which the magnet at the center of the permanent magnet per pole covers the divided magnet at the end. If comprised in this way, since it is the shape which covers the division | segmentation magnet of an edge part with the permanent magnet of a center part, since the magnet shape per arbitrary pole can be formed easily, cost can be reduced. Is possible.

  Furthermore, as a preferred example of the rotor structure of the axial gap type rotating electrical machine of the present invention, a permanent magnet per pole may be composed of a plurality of permanent magnets. If comprised in this way, it will be possible to increase the generated torque by increasing the magnetic flux by forming a plurality of permanent magnets per pole and obtaining the reluctance torque.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a view for explaining an example of an axial gap type rotating electrical machine which is an object of the present invention. In the example shown in FIG. 1, a rotating shaft 2, a disk-shaped rotor 3 fixed to the rotating shaft 2, and a disk-shaped stator 4 provided to face the rotor 3 are connected to an outer case 5- The axial gap type rotating electrical machine 1 is configured by being housed in a case 5 including a first case 1 and a side case 5-2.

  In this example, the rotating shaft 2 is rotatably mounted on the side case 5-2 via bearings 6-1, 6-2. The rotor 3 is composed of a disk-shaped rotor core 7 and a plurality of permanent magnets 8 that are provided in the circumferential direction of the rotor core 7 and constitute a permanent magnet per pole. Yes. The rotor core 7 is composed of a laminated body of electromagnetic steel sheets, a dust core obtained by molding a powder such as iron powder, and the like. Further, the stator 4 has a plurality of stator teeth portions 11 each having a stator coil 10 wound around a cylindrical stator back core portion 9 provided in the side case 5-2. It is arranged and arranged. Note that the stator coil 10 is wound around the stator teeth portion 11 via an insulator 12. Furthermore, the rotation shaft 2 is provided with a rotation sensor 13.

  In the axial gap type rotating electrical machine 1 shown in FIG. 1, the rotor 3 is configured to generate a reaction force in the permanent magnet 8 with respect to the rotating magnetic flux applied from the stator 4 and rotate around the rotating shaft 2. Has been. The permanent magnets 8 are arranged so that the magnetic poles of adjacent permanent magnets are different from each other. Here, a gap 14 called an air gap exists between the rotor 3 and the stator 4 and does not contact each other.

  A feature of the present invention is that, in the axial gap type rotating electrical machine 1 having the above-described configuration, each of the permanent magnets 8 per pole among the plurality of permanent magnets constituting the rotor 3 is divided in the circumferential direction. . Specific examples will be described below.

  FIG. 2 is a diagram for explaining an example of the rotor structure of the axial gap type rotating electrical machine of the present invention, and FIG. 3 is a diagram for explaining the configuration of the permanent magnets 8 per pole in the example shown in FIG. It is. In the example shown in FIGS. 2 and 3, the permanent magnet 8 per pole is configured by combining left and right end portions with a substantially rectangular magnet 8-1 having the same shape, and the central portion is a substantially fan-shaped magnet 8- It consists of two pieces. The permanent magnets 8 (8-1 and 8-2) are held by a rotor core 7 made of a ferromagnetic material such as a dust core, for example. Note that an air gap 21 is disposed beside the permanent magnet 8 in order to prevent a short circuit of magnetic flux between the permanent magnets 8 per one pole.

  As shown in FIGS. 2 and 3, the following effects can be obtained by dividing the permanent magnet 8 per pole in the circumferential direction. That is, the eddy current that is the cause of heat generation of the permanent magnet 8 is generated according to the resistance value of the eddy current circuit, the amount of change in the magnetic flux density, and the rate of change. Since the change in magnetic flux density depends on the shape and torque, and the speed of change depends on the rotational speed, it is effective to increase the resistance value of the circuit in order to reduce the eddy current. Therefore, it is effective to divide the permanent magnet 8 in order to cut the eddy current circuit and increase the resistance value. Here, since the eddy current generated in the permanent magnet 8 is likely to be generated at the end portion where the magnetic flux density change is large, particularly at the front end in the rotation direction, the end portion is finely divided and the center portion is formed as shown in FIGS. By roughly dividing, the amount of heat generated by the permanent magnet 8 can be suppressed even if the number of divisions is reduced. Since the amount of heat generated by the permanent magnet 8 can be suppressed even at a high speed, the speed of the rotating electrical machine can be increased. Further, since the permanent magnet 8 has only two types of shapes, that is, an end portion and a central portion, the cost can be reduced.

  In this example, the following effects can be obtained in addition to the effects described above. That is, by configuring the rotor 3 with the ferromagnetic material and the permanent magnet 8, the generated magnetic force can be increased because the magnetic resistance in the rotor 3 is small and the reluctance torque is obtained. In addition, the rotor shape can be easily produced with high accuracy.

  FIG. 4 is a view for explaining another example of the rotor structure of the axial gap type rotating electric machine of the present invention. In the example shown in FIG. 4, by changing the angle of the side in the circumferential direction of the central magnet 8-2 constituting the permanent magnet 8 per pole, the permanent magnet 8 per pole The shape of the permanent magnet 8 can be inclined, and it is easy to make the entire shape of the permanent magnet 8 per pole into a substantially parallelogram by combining it with the substantially rectangular magnets 8-1 at both ends. . By making the shape of the permanent magnet 8 per pole into a substantially parallelogram, the cogging torque can be reduced and the torque can be increased under certain conditions. Thus, by changing the shape of the magnet 8-2 in the central portion, it becomes possible to easily produce the permanent magnet 8 per pole having an arbitrary shape, and it is possible to reduce the cost. .

  FIG. 5 is a view for explaining still another example of the rotor structure of the axial gap type rotating electric machine of the present invention. In the example shown in FIG. 5, the central magnet 8-2 constituting the permanent magnet 8 per pole is changed by changing the angle of the side in the circumferential direction to a different angle for each side. By combining the substantially rectangular magnets 8-1 at both ends, it is easy to incline the entire shape of the permanent magnet 8 per pole. By making the shape of the permanent magnet 8 per pole into an inclined shape, the cogging torque can be reduced and the torque can be increased under certain conditions. Thus, by changing the shape of the magnet 8-2 in the central portion, it becomes possible to easily produce the permanent magnet 8 per pole having an arbitrary shape, and it is possible to reduce the cost. .

  FIG. 6 is a view for explaining still another example of the rotor structure of the axial gap type rotating electrical machine of the present invention. In the example shown in FIG. 6, a permanent magnet per pole is formed by covering the divided magnet 8-1 at the end with a magnet 8-2 at the center that constitutes the permanent magnet 8 per pole. It is easy to make the entire shape of 8 an arbitrary shape. By making the shape of the permanent magnet 8 per pole an arbitrary shape, the cogging torque can be reduced and the torque can be increased. Thus, it becomes possible to easily produce the permanent magnet 8 per pole having an arbitrary shape by covering the end magnet 8-1 with the magnet 8-2 at the center, and the cost. Can be reduced.

  FIG. 7 is a view for explaining still another example of the rotor structure of the axial gap type rotating electrical machine of the present invention. In the example shown in FIG. 7, the rotor is manufactured by combining members having different shapes by forming a plurality of permanent magnets 8 per pole, here two. With such a structure, the yield of the material is improved and the material can be easily manufactured, so that the cost can be reduced. Further, since the circuit of the eddy current on the lateral surface can be cut off, the efficiency can be increased.

  The present invention is not limited to the above-described embodiments, and many variations and modifications are possible. For example, in the above-described embodiment, the rotating electric machine is described, but it may be an electric motor or a generator. In the embodiment described above, there are 8 poles, but other pole numbers may be used. Further, in the above-described embodiment, the rotor core 7 is a dust core, but other ferromagnetic materials such as an electromagnetic steel plate and amorphous may be used. Furthermore, in the above-described embodiment, a configuration in which a plurality of permanent magnets 8 per one pole are divided into two in the circumferential direction has been introduced. However, a plurality of permanent magnets 8 in the radial direction or a plurality in the axial direction may be used. Absent. In the above-described embodiment, the case where there is one rotor 3 and one stator 4 is described. For example, when there is one rotor 3 and two stators 4, there are two rotors 3. In the case of one stator 4, two rotors 3, three stators 4, three rotors 3, two stators 4, etc., other combinations may be used.

  The rotor structure of the axial gap type rotating electric machine according to the present invention reduces the eddy current generated in the permanent magnet in the axial gap type rotating electric machine in which at least a pair of stators and the rotor are arranged to face each other along the rotation axis. By doing so, heat generation can also be reduced, and it can be suitably used for applications that enable high speed rotation of the rotating electrical machine.

It is a figure for demonstrating an example of the axial gap type rotary electric machine used as the object of this invention. It is a figure for demonstrating an example of the rotor structure of the axial gap type rotary electric machine of this invention. It is a figure for demonstrating the structure of the permanent magnet per pole in the example shown in FIG. It is a figure for demonstrating the other example of the rotor structure of the axial gap type rotary electric machine of this invention. It is a figure for demonstrating the further another example of the rotor structure of the axial gap type rotary electric machine of this invention. It is a figure for demonstrating the further another example of the rotor structure of the axial gap type rotary electric machine of this invention. It is a figure for demonstrating the further another example of the rotor structure of the axial gap type rotary electric machine of this invention. It is a figure which shows the cross section of the radial direction of the conventional axial gap type rotary electric machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial gap type rotary electric machine 2 Rotating shaft 3 Rotor 4 Stator 5 Case 5-1 Outer case 5-2 Side case 6-1, 6-2 Bearing 7 Rotor core 8 Permanent magnet per pole 8-1 End Magnet of part 8-2 Magnet of center part 9 Stator back core part 10 Stator coil 11 Stator tooth part 12 Insulator 13 Rotation sensor 14 Gap 21 Air gap

Claims (8)

  A rotor having a rotor core and a permanent magnet, and a stator having a stator teeth portion and a stator coil wound around the stator teeth portion, and the rotor and the stator are in an axial direction. A rotor structure for an axial gap type rotating electrical machine, wherein the permanent magnet per pole among the permanent magnets is divided in the circumferential direction.   2. The rotor structure of an axial gap type rotating electrical machine according to claim 1, wherein the permanent magnet per pole is divided into a fine end and a central portion.   The rotor structure of an axial gap type rotating electrical machine according to claim 2, wherein the division of the end portion of the permanent magnet per pole is a combination of substantially rectangular shapes.   4. The axial gap type rotating electric machine according to claim 3, wherein the permanent magnet per pole is configured by two types of shapes having a substantially rectangular end portion and a single central portion. 5. Rotor structure.   The rotor structure of the axial gap type rotating electrical machine according to any one of claims 1 to 4, wherein a magnet shape of a central portion of the permanent magnet per one pole is substantially a sector shape.   The axial gap type according to any one of claims 1 to 5, wherein the permanent magnet per pole determines a magnet shape per pole by changing a magnet shape in a central portion. Rotor structure of rotating electric machine.   The rotor of the axial gap type rotating electrical machine according to any one of claims 1 to 6, wherein a magnet at a central portion of the permanent magnet per one pole has a shape covering a split magnet at an end portion. Construction.   The rotor structure of an axial gap type rotating electrical machine according to any one of claims 1 to 7, wherein the permanent magnet per one pole is composed of a plurality of permanent magnets.

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