JP6126873B2 - Permanent magnet rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine having a permanent magnet rotor such as an electric motor or a generator.

  Rotating electrical machines such as electric motors and generators are more demanding to be lighter, thinner and smaller than the market, and recently, demands for energy saving and higher efficiency are increasing as a countermeasure against global warming. For this reason, a high-efficiency permanent magnet type rotating electrical machine using a permanent magnet as a rotor is widely used. For example, recently, automobiles are also being integrated into electric motors from gasoline engines due to environmental problems. In this case, in the permanent magnet type rotating electric machine, strong field control is often used for large torque at low speed, and weak field control is used at high speed, and a motor suitable for this is required. As a motor suitable for this, the structure of a hybrid stepping motor (hereinafter abbreviated as HBSTM) has been attracting attention. On the other hand, there are the following two documents as related prior art.

Nikkei Manufacturing (2008/12) “Considering how to wrap auxiliary magnets and coils” (Nagoya Institute of Technology / NEDO) How to use a stepping motor Masafumi Sakamoto, page 47 Fig. 2.39 Fig. 2.40 Ohmsha

  Since the HBSTM type structure has multiple poles, a large torque required at the start of the vehicle can be obtained at a low speed and a large torque, and if this is weakened and field-controlled, it rotates to a high speed. Also, since the rotor magnet is magnetized in the axial direction, the magnetic field is weakened by applying a magnetic flux from the outside to the rotor with an electromagnet from the outside, and adding a permanent magnet magnetic flux in the direction opposite to the magnet magnetization direction at high speed. Can be easily done. Therefore, Non-Patent Document 1 describes that the motor structure is suitable for an electric vehicle or the like.

  However, the structure of the rotor is such that the N pole and the S pole are divided into two in the axial direction, and the teeth and grooves on the outer periphery of the rotor are alternately arranged, and only half or less of the rotor outer peripheral area contributes to torque generation. Is a drawback. This point is pointed out, and the RM type, which is an improved motor, has been proposed as shown in Non-Patent Document 2, pages 47 to 48 and FIGS. 2.39 and 2.40 (the figure attached to this specification). 5 and FIG. 6). However, since the proposed RM type has a structure in which N poles and S poles are alternately magnetized on the outer periphery of a cylindrical permanent magnet, field control cannot be performed by applying magnetic flux with an electromagnet in the axial direction.

The present invention is realized by the following means.
"Means 1"
A rotating electric machine having a stator and a rotor, wherein the rotor is formed of a substantially disk-shaped or cylindrical first permanent magnet magnetized in the axial direction by soft magnetic iron powder or a magnetic iron plate. The n-arm is sandwiched between two rotor cores projecting a plurality of n arms in the axial direction from the outer circumference or inner circumference of the magnetic disk, and n arms are arranged at the outer circumference or inner circumference of the first permanent magnet. The first permanent magnet and the second permanent magnet are configured by alternately engaging with each other, interposing a second permanent magnet in a circumferential clearance of the arms in which the n arms are alternately engaged. Is an integrally molded product, and after the rotor is incorporated in the stator without magnetization, it is magnetized only in the axial direction, and the second permanent magnet is not magnetized in the circumferential direction .
"Means 2"
The rotating electrical machine according to means 1, wherein an electromagnet magnetic flux is applied in the axial direction of the rotor, and the rotor permanent magnet magnetic flux magnetized in the axial direction is increased or decreased by the direction and strength .
"Means 3"
A rotating electrical machine having means 1 or 2 comprising a bracket made of a molded body of soft magnetic iron powder .

1) About half of the rotor surface of the rotating electrical machine with the HBSTM structure is a tooth groove, and the remainder is occupied by magnetic pole teeth. However, the rotor of the present invention has alternating magnetic pole teeth, so that higher torque is obtained than HBSTM It is done.
2) Since the rotor is magnetized in the axial direction to create a magnetic pole, weak or strong field control can be easily performed using an electromagnet, and a wide range of speed control is possible.
3) Although the rotor according to the present invention is a claw pole type permanent magnet rotor, the interlinkage magnetic flux with the coil is large because a permanent magnet for preventing leakage magnetic flux is provided between the poles.
4) If the bracket is made of a dust core or magnetic iron, and if the coil core is also integrated with the bracket, the field control magnetic flux can be increased and control can be facilitated.

Sectional drawing including the axis | shaft of the rotary machine of an example of this invention AA sectional view perpendicular to the axis of the rotating electrical machine of FIG. Detailed view of rotor of the present invention in which the first and second permanent magnets are separate magnets View from the axial direction of FIG. Diagram of a prior art rotor Sectional view perpendicular to the axis of the rotating electrical machine in FIG.

  This will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of a rotating electrical machine to which the present invention is applied, and is a cross-sectional view including a shaft. Reference numeral 1 denotes a rotor which faces the stator 2 so as to be rotatable through an air gap. The rotor 1 includes reference numerals 11 and 12 formed from a magnetic iron plate or soft magnetic iron powder, a first permanent magnet 13, and a second permanent magnet 14 as necessary. FIGS. 1 and 2 are illustrated by integrally forming reference numerals 13 and 14. In this case, the first permanent magnet 13 and the second permanent magnet 14 are integrally formed of permanent magnets of the same material. Details of the rotor will be described later with reference to FIGS.
Reference numeral 3 denotes a stator winding. Referring to FIG. 2, which is a cross-sectional AA view perpendicular to the axis of the rotating electrical machine in FIG. 1, an example of a 6-winding pole structure with 6 slots and concentrated winding is shown.
Reference numeral 4 denotes a rotor shaft, and reference numeral 5 denotes a bearing such as a ball bearing. Reference numeral 6 denotes brackets which are located on both sides in the rotor axial direction, support the rotor via bearings 5, and are fixed to the stator 2. In this case, a coil 8 is wound around the bracket 6 and is a part 7 of the bracket 6. The first permanent magnet 13 of the rotor 1 is magnetized in the axial direction, but the coil 8 is excited to weaken the rotor magnetic flux during high speed rotation, strengthen it during low speed rotation, and none during medium speed rotation. The field control is performed by excitation. When the motor rotates, there is a change in the magnetic flux at reference numerals 11 and 12, and iron loss occurs. Therefore, it is desirable that the materials denoted by reference numerals 11 and 12 are so-called dust cores obtained by pressure-molding the above-described soft magnetic iron powder by electrically insulating it with a resin coating or the like. Thereby, eddy current loss in iron loss can be eliminated. Also, the lack of magnetic permeability is good for the three-dimensional magnetic path of the claw pole structure. The field control magnetic flux of the electromagnet also passes through the dust core more easily than the stacking direction of the laminated core.

3 is a detailed cross-sectional view of the rotor portion of the present invention, and FIG. 4 is a view seen from the axial direction of FIG. Reference numerals 11 and 12 are magnetic poles made of an electromagnetic iron plate or electromagnetic soft iron powder by pressure molding or the like. It is also called a claw pole or clotase. And the code | symbol 13 which becomes the 1st permanent magnet magnetized to the axial direction using the code | symbol 11 and the code | symbol 12 is clamped. That is, a plurality of n arms are arranged in the axial direction from the outer periphery or inner periphery of a magnetic disk formed of soft magnetic iron powder by using a first permanent magnet having a substantially columnar or cylindrical code 13 magnetized in the axial direction. The rotor cores 11 and 12 projecting from each other are sandwiched between n arms on the outer periphery or inner periphery of the first permanent magnet 13 so that they are alternately meshed with a gap. It is. Reference numerals 11 and 12 are the same product, but when configured as a rotor, their orientations are reversed in the axial direction, and the n arms are combined with a gap at equal intervals so that they do not contact each other alternately. . In the circumferential gap between the arms that are alternately engaged with the n arms, a second permanent magnet having a reference numeral 14 magnetized so as to face each other with the same polarity is interposed. In this way, the second permanent magnet 14 is interposed by the magnetization of the first permanent magnet 13 and the arms of reference numerals 11 and 12 are magnetized to have different polarities. When the motor is used, the flux linkage with the stator coil decreases. This is prevented by interposing a second permanent magnet having a reference numeral 14 magnetized so that the same polarity is opposed to each other in a gap between the reference numerals 11 and 12. That is, as illustrated in FIG. 4, since the reference numeral 11 is magnetized to the N pole and the reference numeral 12 is magnetized to the S pole, the reference numeral 14 contacts the arm of the reference numeral 11 and the N pole contacts the arm of the reference numeral 12. On the side, the reference numeral 14 is magnetized in the circumferential direction of the rotor 1 so as to be magnetized to the south pole, thereby preventing leakage magnetic flux between the reference numerals 11 and 12.
The illustrated FIGS. 1 to 4 show the case where the number of pole pairs is 2 and the number of rotor poles is 4 when n = 2. In addition, although an inner rotation (inner rotor) type rotating electric machine is shown, an outer rotation type is also possible. In the case of the outer rotation type, the claw poles 11 and 12 are alternately meshed with each other at the inner peripheral portion of the first permanent magnet 13.

  FIGS. 3 and 4 show the first permanent magnet 13 and the second permanent magnet 14 for the rotor as separate magnets. The coercive force of the second permanent magnet 14 is preferably a permanent magnet made of a material larger than the coercive force of the first permanent magnet 13. For example, the first permanent magnet 13 is an alnico magnet (Hc = 0.8 kOe) or a ferrite magnet (Hc = 3.7 kOe), and the second permanent magnet 14 is a neodymium magnet (Hc = 12 kOe) or a samarium cobalt magnet (Hc = 8 kOe), the second permanent magnet 14 is difficult to be demagnetized during field control. This is because when the second permanent magnet 14 has a weak coercive force and the magnetization is lost, the effect of preventing the leakage magnetic flux between the reference numerals 11 and 12 decreases. Further, since the coercive force of the first permanent magnet 13 is small, the field coil 8 can easily perform the weakening control to the rotation at the high speed rotation and the strong field control at the low speed rotation. In this case, for example, when field-weakening control is being performed, a method in which an excitation current having an appropriate value is continuously supplied to the field coil 8 is applied to the field coil 8 after a large current is instantaneously applied in the reverse magnetization direction. The excitation current is turned off and the first permanent magnet 13 is appropriately reduced so that it can be operated at high speed. During low speed operation, a large current in the magnetization direction is instantaneously supplied to the field coil 8 and then the excitation current is supplied. The first permanent magnet 13 may be returned to the fully magnetized state to correspond to low speed operation.

  FIGS. 1 and 2 are views in which the first permanent magnet 13 and the second permanent magnet 14 for the rotor are integrally molded. In this way, the motor becomes inexpensive. In this case, the first permanent magnet 13 and the second permanent magnet 14 can be integrally molded, and the rotor 1 can be incorporated into the stator 2 by axial magnetization and circumferential magnetization of 2n poles. In the figure, this is a case of n = 2 n = 4. At this time, since the latter magnetization may be on the rotor surface, the magnetization force may be adjusted so that the magnetization does not reach the first permanent magnet 13.

  As described above, the first permanent magnet 13 is magnetized in the axial direction, and the second permanent magnet 14 is magnetized in the circumferential direction. Reference numerals 13 and 14 are preferably separate magnets having different coercive forces. However, if the code 13 and the code 14 are separate magnets and n is a large number of multipoles, this method results in an expensive motor. Therefore, when focusing on low cost, the first permanent magnet 13 and the second permanent magnet 14 are integrated as shown in FIGS. 1 and 2, the magnet magnetization is also incorporated in the stator, the bracket is attached, and the motor is assayed. Later, only the axial direction can be magnetized from the outside of the motor. In this case, the second permanent magnet 14 is magnetized not in the circumferential direction but in the axial direction. However, if the second permanent magnet 14 is magnetized in the axial direction, the leakage flux passes perpendicularly to the magnetization direction of the second permanent magnet 14 as compared with the case where the second permanent magnet 14 is not magnetized. Although the magnetic resistance is small, the leakage magnetic flux is difficult to pass through, and the leakage magnetic flux prevention effect is produced by an inexpensive method. Since the field strengthening or weakening and the effect of strengthening or weakening the axial magnetization of the second permanent magnet 14 coincide with each other, the second permanent magnet 14 has an effect of preventing leakage magnetic flux between adjacent arms. Become. This means that the first permanent magnet and the second permanent magnet of the means 4 are integrally molded, and after the rotor is incorporated in the stator without magnetization, it is magnetized only in the axial direction, and the second permanent magnet is circumferentially magnetized. This corresponds to a rotating electrical machine that does not perform the above.

  FIG. 5 is a view of a conventional rotor, and is an external view of a rotor whose HB type is HBSTM. From this figure, it can be seen that about half of the rotor surface is a tooth groove, and the tooth magnetic pole for torque generation is less than half of the remaining surface area. The improved version of the rotor is the RM type. FIG. 6 shows the RM type incorporated into the stator and viewed from the axial direction. However, as described above, in this RM type structure, the torque generation utilization factor of the rotor surface area is doubled to the same extent as the present invention, but the magnetization direction of the rotor magnetic pole is not the axial direction, so the field control is not easy. Had.

  In the present embodiment, the example in which the rotating electrical machine is used as a motor has been described. However, the rotating electrical machine may be used as a generator, and in this case, an inexpensive claw pole type stator is used as the stator. It may be used as a single-phase structure having one annular coil. As a result, a single-phase alternating current is obtained, which is suitable for a bicycle generator or the like. If the stator is combined with a stator having a three-phase winding with a normal laminated iron core, a three-phase alternating current can be obtained.

  The rotating electrical machine according to the present invention can be used for an electric motor or a generator, is inexpensive, robust, light and thin, suitable for high torque and high efficiency, and is capable of performing a wide range of phase control by field control. Therefore, it is expected to make a significant industrial contribution.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 3 Winding 4 Rotor shaft 5 Bearing 6 Bracket 7 Coil core 8 Field coil 11, 12 Rotor core 13 1st permanent magnet 14 2nd permanent magnet

Claims (3)

A rotating electric machine having a stator and a rotor,
The rotor includes a plurality of substantially disc-shaped or cylindrical first permanent magnets magnetized in the axial direction in the axial direction from the outer periphery or inner peripheral portion of a magnetic disc formed of soft magnetic iron powder or a magnetic iron plate. n arms are sandwiched between two protruding rotor cores, and n arms are alternately meshed with an outer periphery or an inner periphery of the first permanent magnet.
A second permanent magnet is interposed in the circumferential clearance of the arms that are alternately meshed with the n arms;
The first permanent magnet and the second permanent magnet are integrally molded, and the rotor is magnetized only in the axial direction after being incorporated in the stator without magnetization, and the second permanent magnet is circumferentially A rotating electric machine characterized by not being magnetized . However, n is an integer of 2 or more. In the rotating electrical machine according to claim 1,
A rotating electrical machine characterized in that an electromagnet magnetic flux is applied in the axial direction of the rotor, and the rotor permanent magnet magnetic flux magnetized in the axial direction is increased or decreased according to the direction and strength . In the rotating electrical machine according to claim 1 or 2 ,
A rotating electrical machine comprising a bracket made of a molded body of soft magnetic iron powder .

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