Rotor structure of rotating electric machine and control device for rotating electric machine

Abstract

To efficiently change the magnetization state of a variable magnetic force magnet.SOLUTION: A rotor structure of a rotating electrical machine includes a plurality of variable magnetic force magnets 51, 52 arranged in a circumferential direction, each of which is capable of changing its magnetization state in the circumferential direction by a predetermined magnetic flux, holes (first accommodating hole H71, second accommodating hole H72) arranged around the variable magnetic force magnets 51, 52, and non-magnetic conductors 73, 74 arranged within the holes (first accommodating hole H71, second accommodating hole H72) and which generate eddy currents such that a magnetic flux that repels the predetermined magnetic flux is generated by the predetermined magnetic flux.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The technology disclosed herein belongs to the technical field related to the rotor structure of a rotating electrical machine and the control device of a rotating electrical machine.

Background Art

[0002] In recent years, as a rotor of a rotating electrical machine, a rotor having a magnetic force fixed magnet whose magnetization state is difficult to change and a variable magnet whose magnetization state is easier to change has been proposed.

[0003] Patent Document 1 discloses a rotor structure provided on a rotor core, having a plurality of magnetic pole portions arranged in the circumferential direction. Each of the plurality of magnetic pole portions includes a magnetic force fixed magnet magnetized in the radial direction, a first magnetic force variable magnet and a second magnetic force variable magnet respectively arranged on one end side and the other end side in the circumferential direction of the magnetic force fixed magnet, each of which can change the magnetization state in the circumferential direction by a predetermined magnetic flux, a first auxiliary magnet arranged between the magnetic force fixed magnet and the first magnetic force variable magnet and magnetized in a direction to inhibit the flow of magnetic flux between the outer radial end of the magnetic force fixed magnet and the first magnetic force variable magnet, and a second auxiliary magnet arranged between the magnetic force fixed magnet and the second magnetic force variable magnet and magnetized in a direction to inhibit the flow of magnetic flux between the outer radial end of the magnetic force fixed magnet and the second magnetic force variable magnet.

[0004] Further, in Patent Document 1, a first air gap portion (hole portion) is provided outside the first auxiliary magnet in the radial direction, and a second air gap portion (hole portion) is provided outside the second auxiliary magnet in the radial direction.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the rotor structure described in Patent Document 1, the hole portion suppresses the short-circuit of magnetic flux between the radially outer end of the magnetic force fixing magnet and the first magnetic force variable magnet and between the radially outer end of the magnetic force fixing magnet and the second magnetic force variable magnet. In this way, by providing the hole portion, it is possible to make it difficult for magnetic flux to pass through and control the direction of the magnetic flux.

[0007] By the way, when a magnetic force variable magnet is provided as in Patent Document 1, when changing the magnetization state of the magnetic force variable magnet, it is required to efficiently input magnetic flux to the magnetic force variable magnet. Since the magnetic flux from the stator when changing the magnetization state of the magnetic force variable magnet is relatively large, there is a possibility that the magnetic flux may enter the hole portion even if a hole portion is provided as in Patent Document 1. When the magnetic flux enters the hole portion, it becomes difficult to efficiently change the magnetization state of the magnetic force variable magnet. Therefore, there is room for improvement from the viewpoint of efficiently changing the magnetization state of the magnetic force variable magnet.

[0008] The technology disclosed herein has been made in view of such a point, and its object is to efficiently change the magnetization state of the magnetic force variable magnet.

Means for Solving the Problem

[0009] In order to solve the above problems, a first aspect of the technology disclosed herein is directed to a rotor structure of a rotating electrical machine including a rotor having a rotor core and a stator having a stator core disposed with a gap from the rotor core. A plurality of magnetic force variable magnets arranged side by side in the circumferential direction, each of which can change the magnetization state in the circumferential direction by a predetermined magnetic flux, a hole portion disposed adjacent to the magnetic force variable magnet in the radial direction or the axial direction, and disposed in the hole portion, a non-magnetic conductor that generates an eddy current that generates a magnetic flux repelling the predetermined magnetic flux by the predetermined magnetic flux.

[0010] In the first aspect, the non-magnetic conductor generates a magnetic flux that repels a predetermined magnetic flux due to eddy currents, making it difficult for the magnetic flux from the stator to enter the hole portion. As a result, when changing the magnetization state of the magnet with variable magnetic force and the like, the magnetic flux can be easily made to flow into the magnet with variable magnetic force. Consequently, the magnetization state of the magnet with variable magnetic force can be efficiently changed.

[0011] A second aspect of the technology disclosed herein is that, in the first aspect, the non-magnetic conductor has a longitudinally extending portion that extends in a direction perpendicular to the circumferential direction toward the magnet with variable magnetic force.

[0012] In the second aspect, the non-magnetic conductor can be brought closer to the magnet with variable magnetic force. As a result, the intrusion of the magnetic flux into the hole portion can be effectively suppressed, so that the magnetization state of the magnet with variable magnetic force can be efficiently changed.

[0013] A third aspect of the technology disclosed herein is that, in the first aspect, a gap is provided between the non-magnetic conductor and the inner peripheral surface of the hole portion.

[0014] In the third aspect, when the magnetic flux from the stator is relatively small other than when changing the magnetization state of the magnet with variable magnetic force, it becomes difficult for the magnetic flux to reach the non-magnetic conductor, and it becomes difficult for eddy currents to be generated. As a result, it is possible to suppress the deterioration of the efficiency of the rotating electrical machine due to the magnetic flux formed by the eddy currents in the non-magnetic conductor.

[0015] A fourth aspect of the technology disclosed herein is that, in the third aspect, the rotating electrical machine is a radial gap motor in which the rotor and the stator are arranged with a gap in the radial direction, and further includes end plates provided at both axial ends of the rotor core, the hole portion is arranged adjacent to the magnet with variable magnetic force in the radial direction, and the non-magnetic conductor is fixed to the end plates, respectively.

[0016] In the fourth aspect, the non-magnetic conductor can be used as a reinforcing member of the end plate, and the strength of the rotor can be improved.

[0017] The fifth aspect of the technology disclosed herein is that, in the third aspect, the rotating electrical machine is an axial-gap motor in which the rotor and the stator are arranged with a gap in the axial direction, and further includes an inner wall portion provided on the radially inner side of the rotor core and an outer wall portion provided on the radially outer side of the rotor core. The hole portion is arranged adjacent to the magnet with variable magnetic force in the axial direction, and the non-magnetic conductor is fixed to the inner wall portion and the outer wall portion, respectively.

[0018] In the fifth aspect, the non-magnetic conductor can be used as a reinforcing member of the rotor, and the strength of the rotor can be improved.

[0019] The sixth aspect of the technology disclosed herein is that, in the first aspect, the rotor core includes a plurality of magnetic pole portions arranged in the circumferential direction and having the magnet with variable magnetic force. Each magnetic pole portion has a magnet with fixed magnetic force having a predetermined magnetic force. The magnet with variable magnetic force includes a first magnet with variable magnetic force arranged on one end side in the circumferential direction of the magnet with fixed magnetic force in each magnetic pole portion, and a second magnet with variable magnetic force arranged on the other end side in the circumferential direction of the magnet with fixed magnetic force in each magnetic pole portion. In two adjacent magnetic pole portions in the circumferential direction, the first magnet with variable magnetic force of one magnetic pole portion and the second magnet with variable magnetic force of the other magnetic pole portion are adjacent in the circumferential direction.

[0020] In the sixth aspect, since a large number of magnets with variable magnetic force are provided, it is required to efficiently input a predetermined magnetic flux into the magnets with variable magnetic force. Therefore, the effect of suppressing the intrusion of magnetic flux into the hole portion by providing the non-magnetic conductor can be more appropriately exerted.

[0021] The seventh aspect of the technology disclosed herein is that, in the sixth aspect, the hole portion includes a first hole portion provided in a region between the magnet with fixed magnetic force and the first magnet with variable magnetic force in each magnetic pole portion, and a second hole portion provided in a region between the magnet with fixed magnetic force and the second magnet with variable magnetic force in each magnetic pole portion. Non-magnetic conductors are arranged in each of the first hole portion and the second hole portion.

[0022] In the seventh aspect, since the nonmagnetic conductor is provided for each of the first magnetically variable magnet and the second magnetically variable magnet, it is possible to suppress the magnetic flux from the stator from entering the first hole portion and the second hole portion near the first magnetically variable magnet and the second magnetically variable magnet. Thereby, the magnetization state of the magnetically variable magnet can be efficiently changed.

[0023] The eighth aspect of the technology disclosed herein is directed to a control device for a rotating electrical machine having the rotor structure described in any one of the first to seventh aspects, and includes a control unit that controls a pulse current for generating the predetermined magnetic flux. The control unit executes pulse control in which, after the amplitude of the pulse current reaches the maximum value, during the pulse period of the pulse current, the current is increased and decreased with a width smaller than the amplitude of the pulse current.

[0024] In the eighth aspect, the magnetization state of the magnetically variable magnet can be changed more efficiently. That is, since the magnetization state of the magnetically variable magnet may be executed while the rotor is rotating, the magnetic flux input to the nonmagnetic conductor may change as the rotor rotates. When the magnetic flux input to the nonmagnetic conductor decreases, eddy currents that generate a magnetic flux along the predetermined magnetic flux are generated, so that the efficiency of changing the magnetization state of the magnetically variable magnet may deteriorate. If pulse control is executed as in the eighth aspect, even if eddy currents that generate a magnetic flux along the predetermined magnetic flux are generated in the nonmagnetic conductor, the largest possible magnetic flux can be input to the magnetically variable magnet. Thereby, the magnetization state of the magnetically variable magnet can be changed more efficiently.

[0025] In the ninth aspect, in the pulse control, the control unit changes the magnitude and number of times of increasing and decreasing the current in consideration of the magnetization rate of the magnetically variable magnet, the rotation speed of the rotor, and the power supply voltage.

[0026] In the ninth aspect, according to the operating state of the rotating electrical machine, by appropriately changing the magnitude and number of times of increasing and decreasing the current in the pulse control, the magnetic flux input to the magneto-variable magnet can be made as large as possible. As a result, the magnetization state of the magneto-variable magnet can be changed more efficiently.

Advantages of the Invention

[0027] As described above, according to the technology disclosed herein, the magnetization state of the magneto-variable magnet can be changed efficiently.

Brief Description of the Drawings

[0028]

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MODE FOR CARRYING OUT THE INVENTION

[0029] Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

[0030] (Embodiment 1) 〈Configuration of Vehicle〉 FIG. 1 schematically shows an automobile 1 equipped with a drive motor 2 having a rotor structure according to Embodiment 1 of the present invention. The automobile illustrated here is a hybrid vehicle capable of traveling using electric power. As a drive source of the automobile, an engine 3 is mounted together with a drive motor 2 (magnetically variable motor) to which the disclosed technology is applied. These cooperate to rotationally drive two wheels (drive wheels 4R) that are symmetrically located among the four wheels 4F, 4F, 4R, 4R. Thereby, the automobile 1 moves (travels). Note that the automobile 1 may be an electric vehicle equipped with only the drive motor 2. The automobile 1 may also be four-wheel drive.

[0031] In the case of this motor vehicle 1, the engine 3 is arranged on the front side of the vehicle body, and the drive wheels 4R are arranged on the rear side of the vehicle body. That is, this motor vehicle 1 is a so-called FR vehicle. In the case of this motor vehicle 1, as the drive source, the engine 3 is the main one rather than the drive motor 2, and the drive motor 2 is used in a form that assists the drive of the engine 3 (so-called mild hybrid). The drive motor 2 is also used not only as a drive source but also as a generator during regeneration.

[0032] The engine 3 is, for example, an internal combustion engine that burns gasoline as fuel. The engine 3 may be a diesel engine that uses light oil as fuel. The drive motor 2 is connected to the rear of the engine 3 via the first clutch 5. The drive motor 2 is a permanent magnet synchronous motor driven by three-phase alternating current.

[0033] As described above, this drive motor 2 is a magnetic force variable motor. Its rotor is provided with a magnetic force fixed magnet 40 and magnetic force variable magnets 51, 52, which will be described later, and is configured to be able to change the magnetic force. In order to improve the motor performance, the structure of its rotor has been devised. The details of the drive motor 2 will be described later.

[0034] The drive motor 2 is connected to the battery 7 via the inverter 6. The battery 7 is composed of a plurality of lithium-ion batteries. The rated voltage of the battery 7 is 50 V or less (specifically 48 V). The battery 7 supplies DC power to the inverter 6. The inverter 6 converts the DC power into three-phase alternating current with different phases and supplies it to the drive motor 2. Thereby, the drive motor 2 rotates.

[0035] Behind the drive motor 2, a transmission 9 is connected via the second clutch 8. The transmission 9 is a multi-stage automatic transmission (so-called AT). The rotational power output by the engine 3 and / or the drive motor 2 is output to the transmission 9 through the second clutch 8. The transmission 9 is connected to the differential gear via the propeller shaft.

[0036] The differential gear is connected to the left and right drive wheels 4R via a pair of drive shafts. When the vehicle 1 is running (under power), the rotational power shifted by the transmission 9 is distributed by the differential gear and transmitted to each drive wheel 4R.

[0037] When the vehicle 1 is decelerating (during regeneration), energy consumed by using the drive motor 2 is recovered. Specifically, when the vehicle 1 brakes, the second clutch 8 remains engaged while the first clutch 5 is released. By doing so, the drive motor 2 is rotated by the rotational power of the drive wheels to generate electricity. The electric power is charged to the battery 7 to recover energy.

[0038] The vehicle 1 has sensors in drive system devices such as the engine 3, drive motor 2, and transmission 9. The engine 3 has an engine rotation sensor 81 that detects the rotational speed of the engine 3. The drive motor 2 has a motor rotation sensor 83 that detects the rotational speed of the drive motor 2 and a magnetic force sensor 84 that detects the magnetic forces of the magnetically variable magnets 51, 52. The transmission 9 has a transmission sensor 82 that detects the operating state of the transmission 9. Also, in the connection path between the drive motor 2 and the inverter 6, there is a current sensor 85 that detects the current supplied to the drive motor 2. The current sensor 85 can estimate the voltage of the battery 7, that is, the power supply voltage.

[0039] The vehicle 1 is equipped with control system devices such as an engine control unit (ECU) 91, a motor control unit (MCU) 92, a transmission control unit (TCU) 93, and a general control unit (GCU) 94.

[0040] <Operating Region of Drive Motor> Fig. 2 exemplifies a map showing the operating region of the drive motor 2. In this map, the operating region that the drive motor 2 can output is defined by a load upper limit line Tm indicating the upper limit value of torque (load) according to the rotational speed.

[0041] The operating range of the variable magnetic force motor is divided into a plurality of magnetization regions according to the magnetic force of the rotor 10 so that the power factor is optimized. In the illustrated map, it is divided into three magnetization regions.

[0042] That is, a first magnetization region Rm1 including the maximum torque T1 and extending to the high-load side along the load upper limit line, a second magnetization region Rm2 extending to the lower-load side than the first magnetization region Rm1, and a second magnetization region Rm2. It extends to the lower-load side than Rm2 and is divided into a third magnetization region Rm3 including the torque T0 at which the drive motor 2 runs idle on the high-rotation side (torque that does not contribute to the running of the automobile 1).

[0043] An optimal magnetic force corresponding to each output is set for each of these magnetization regions Rm. Usually, the magnetic force of the first magnetization region Rm1 is set higher than the magnetic force of the second magnetization region Rm2, and the magnetic force of the third magnetization region Rm3 is set lower than the magnetic force of the second magnetization region Rm2.

[0044] During the running of the automobile 1, the magnetization region Rm is predicted based on the operating state of the drive motor 2. When shifting to the magnetization region Rm, the magnetic force of the rotor 10 is changed according to the magnetic force of the magnetization region. For example, when shifting from the second magnetization region Rm2 to the first magnetization region Rm1, magnetization is executed by the drive motor 2. When shifting from the second magnetization region Rm2 to the third magnetization region Rm3, demagnetization is executed by the drive motor 2.

[0045] Although details will be described later, when magnetizing or demagnetizing, a pulsed large current is passed through a predetermined coil 22 at the timing when the rotor 10 reaches a predetermined position with respect to the stator 20. By doing so, a strong magnetic field is generated from the stator 20 for the variable magnetic force magnets 51 and 52 to be processed. Thereby, the variable magnetic force magnets 51 and 52 are magnetized until a predetermined magnetic force is obtained.

[0046] The directions of the magnetic fields generated during magnetization and demagnetization are opposite. During magnetization, the magnetic forces of the magnetism-variable magnets 51 and 52 are magnetized so as to be in the same direction as the magnetic force of the magnetism-fixed magnet 40. During demagnetization, the magnetic forces of the magnetism-variable magnets 51 and 52 are magnetized so as to be in the opposite direction to the magnetic force of the magnetism-fixed magnet 40. Depending on the magnetization state, the direction of the magnetic force of the magnetism-variable magnets 51 and 52 can be reversed or the strength of the magnetic force can be changed in magnitude.

[0047] However, magnetization is subject to the limitations of in-vehicle equipment. That is, in order to strongly magnetize the magnetism-variable magnets 51 and 52, it is necessary to supply a large current to the drive motor 2, and it is subject to the voltage of the battery 7 and the capacity of the inverter 6.

[0048] Although it is conceivable to increase the size of these devices, it is difficult to increase the size because they are mounted in a vehicle. Therefore, in the technology disclosed herein, the structure of the drive motor 2, particularly the structure of the rotor 10, is devised so that magnetization can be efficiently performed even under the limited conditions of using existing devices. In addition, the control for changing the magnetization state of the magnetism-variable magnets 51 and 52 is devised.

[0049] <Configuration of Drive Motor> FIG. 3 shows a cross section of the drive motor 2. As shown in FIG. 3, the drive motor 2 is a six-pole motor having six magnetic pole portions 12 described later. The drive motor 2 includes a rotor 10, a stator 20, and a shaft 30. The drive motor 2 is a radial gap motor, and the rotor 10 and the stator 20 are arranged with a gap in the radial direction. Note that the number of poles of the drive motor 2 is not particularly limited, and may be seven poles or more.

[0050] In the following description, the rotational axis direction or the axial direction represents the direction in which the rotational axis Q extends. The radial direction represents the radial direction centered on the rotational axis Q. The circumferential direction represents the direction around the rotational axis Q. In the radial direction, the side far from the rotational axis Q is referred to as the "radial outer side", and the side close to the rotational axis Q is referred to as the "radial inner side".

[0051] 〔Stator〕 The stator 20 faces the rotor 10 with a gap in the radial direction. The stator 20 has a stator core 21 and a plurality of coils 22.

[0052] The stator core 21 has an annular back yoke 21a and a plurality (nine) of teeth 21b that project radially inward from the back yoke 21a. For example, the stator core 21 is a laminated core formed by laminating a plurality of electromagnetic steel sheets with high magnetic permeability in the axial direction of the rotating shaft.

[0053] The plurality of coils 22 are wound around the plurality of teeth 21b. When the plurality of coils 22 are energized, magnetic flux is generated in the plurality of coils 22. For example, the plurality of coils 22 constitute a three-phase coil group consisting of a U-phase, a V-phase, and a W-phase with different phases of the flowing current. The coils 22 of each phase are arranged in order in the circumferential direction.

[0054] In this example, the magnetic flux generated in the plurality of coils 22 includes a rotating magnetic flux for rotating the rotor 10 and a variable magnetic flux (predetermined magnetic flux) for changing the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 described later.

[0055] For example, by supplying an alternating current to the plurality of coils 22, a rotating magnetic flux is generated in the plurality of coils 22. The rotor 10 rotates due to this rotating magnetic flux. Also, during the rotation (or stop) of the rotor 10, by supplying a predetermined current (for example, a pulse current larger than the alternating current that generates the rotating magnetic flux) to the plurality of coils 22 for a predetermined time, a variable magnetic flux is generated in the plurality of coils 22. The magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 described later change due to this variable magnetic flux.

[0056] 〔Rotor〕 Next, with reference to FIGS. 3 and 4, the rotor 10 will be described. The rotor 10 includes a rotor core 11 and a plurality of magnetic pole portions 12.

[0057] 〔Rotor Core〕 The rotor core 11 is formed in a cylindrical shape. For example, the rotor core 11 is a laminated core in which a plurality of electromagnetic steel sheets with high magnetic permeability are laminated in the axial direction. A shaft hole is provided in the central portion of the rotor core 11. A shaft 30 is inserted and fixed in the shaft hole.

[0058] 〔Magnetic Pole Portion〕 A plurality of magnetic pole portions 12 are provided on the rotor core 11 and are arranged in the circumferential direction. Each of the plurality of magnetic pole portions 12 has a magnetic force fixed magnet 40, a first magnetic force variable magnet 51, a second magnetic force variable magnet 52, a first auxiliary magnet 61, and a second auxiliary magnet 62.

[0059] The magnetic pole portions 12 adjacent to each other in the circumferential direction of the rotor 10 have different magnetic properties. Specifically, the magnetization directions of the magnetic force fixed magnet 40, the first auxiliary magnet 61, and the second auxiliary magnet 62 are opposite to each other.

[0060] 〈Magnetic Force Fixed Magnet〉 The magnetic force fixed magnet 40 is embedded in the rotor core 11. In this example, the magnetic force fixed magnet 40 is accommodated in a magnetic force fixed magnet hole H40 provided in the rotor core 11. Further, the magnetic force fixed magnet 40 extends in a direction orthogonal to the radial direction (tangential direction). Specifically, the magnetic force fixed magnet 40 has a rectangular cross-sectional shape and its longitudinal direction faces the tangential direction.

[0061] For the magnetic force fixed magnet 40, a magnet such as a neodymium magnet with a high magnetic flux density and a large coercive force is used. The magnetic force fixed magnet 40 does not substantially change its magnetization state even when a magnetic flux generated by a predetermined magnetic flux, for example, a large current (e.g., 750 Arms) that the battery 7 and the inverter 6 can output, is applied. The coercive force of the magnetic force fixed magnet 40 is higher than the coercive forces of the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52. These magnetic force fixed magnets 40 may be made of different magnetic materials, but in this rotor 10, the same magnetic material is used.

[0062] 〈Magnetic Force Variable Magnet〉 The first magnet with variable magnetic force 51 included in each of the plurality of magnetic pole portions 12 is adjacent to the second magnet with variable magnetic force 52 included in another magnetic pole portion 12 adjacent to one end side in the circumferential direction of the magnetic pole portion 12 (adjacent in the clockwise direction in FIGS. 3 and 4), with the q-axis sandwiched therebetween. The q-axis is an imaginary line that passes between two adjacent magnetic pole portions 12 in the circumferential direction and extends in the radial direction.

[0063] Also, in each of the plurality of magnetic pole portions 12, the first magnet with variable magnetic force 51 and the second magnet with variable magnetic force 52 are arranged symmetrically with respect to the d-axis. The d-axis is an imaginary line that passes through the center in the circumferential direction of the magnet with fixed magnetic force 40 and extends in the radial direction.

[0064] 〈First magnet with variable magnetic force〉 The first magnet with variable magnetic force 51 is arranged on one end side in the circumferential direction of the magnet with fixed magnetic force 40. The first magnet with variable magnetic force 51 faces the magnet with fixed magnetic force 40 with a gap therebetween in the circumferential direction. The circumferential length between the first magnet with variable magnetic force 51 and the q-axis is shorter than the circumferential length between the first magnet with variable magnetic force 51 and the magnet with fixed magnetic force 40.

[0065] The first magnet with variable magnetic force 51 is embedded in the rotor core 11. In this example, the first magnet with variable magnetic force 51 is accommodated in a first magnet hole with variable magnetic force H51 provided in the rotor core 11. Also, the first magnet with variable magnetic force 51 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the first magnet with variable magnetic force 51 has a rectangular cross-sectional shape and its longitudinal direction faces the direction parallel to the q-axis.

[0066] 〈Second magnet with variable magnetic force〉 The second magnet with variable magnetic force 52 is arranged on the other end side in the circumferential direction of the magnet with fixed magnetic force 40. The second magnet with variable magnetic force 52 faces the magnet with fixed magnetic force 40 with a gap therebetween in the circumferential direction. The circumferential length between the second magnet with variable magnetic force 52 and the q-axis is shorter than the circumferential length between the second magnet with variable magnetic force 52 and the magnet with fixed magnetic force 40.

[0067] The second magneto - variable magnet 52 is embedded in the rotor core 11. In this example, the second magneto - variable magnet 52 is accommodated in a second magneto - variable magnet hole H52 provided in the rotor core 11. Also, the second magneto - variable magnet 52 extends along the q - axis (adjacent q - axes in the circumferential direction). Specifically, the second magneto - variable magnet 52 has a rectangular cross - sectional shape and its longitudinal direction faces a direction parallel to the q - axis.

[0068] 〈Magnetic Characteristics of Magneto - variable Magnet〉 For the first magneto - variable magnet 51 and the second magneto - variable magnet 52, magnets such as neodymium magnets, samarium - cobalt magnets, and alnico magnets, which have a high magnetic flux density but a small coercive force, are used. Each of the first magneto - variable magnet 51 and the second magneto - variable magnet 52 can change its magnetic force by a magnetic flux generated by a predetermined magnetic flux, for example, a large current (e.g., 750 Arms) that the battery 7 and the inverter 6 can output. The first magneto - variable magnet 51 and the second magneto - variable magnet 52 are hardly magnetized at the magnitude of the current when the drive motor 2 is normally driven. At this time, the first magneto - variable magnet 51 and the second magneto - variable magnet 52 also function as permanent magnets.

[0069] In this example, the easy magnetization direction of each of the first magneto - variable magnet 51 and the second magneto - variable magnet 52 faces the circumferential direction, more specifically, the direction (tangential direction) orthogonal to the radial direction. The difficult magnetization direction of the first magneto - variable magnet 51 faces the direction orthogonal to the easy magnetization direction of the first magneto - variable magnet 51 (the radial direction in this example). The difficult magnetization direction of the second magneto - variable magnet 52 faces the direction orthogonal to the easy magnetization direction of the second magneto - variable magnet 52 (the radial direction in this example).

[0070] Also, in this example, each of the first magnetism variable magnet 51 and the second magnetism variable magnet 52 can be switched between a state in which the magnetization direction faces the first direction, a state in which the magnetization direction faces the second direction, and a zero state in which the magnetic force is substantially zero. The first direction is a direction in which the magnetic flux (effective magnetic flux) linking with the teeth 21b increases. The second direction is a direction in which the magnetic flux (effective magnetic flux) linking with the teeth 21b decreases. For example, when the magnetization direction of the magnetism fixed magnet 40 is a direction facing radially outward, the first direction is a direction from the first magnetism variable magnet 51 (or the second magnetism variable magnet 52) toward the magnetism fixed magnet 40, and the second direction is a direction from the magnetism fixed magnet 40 toward the first magnetism variable magnet 51 (or the second magnetism variable magnet 52).

[0071] In the following description, a state in which the magnetization directions of the first magnetism variable magnet 51 and the second magnetism variable magnet 52 face the first direction is referred to as a magnetization increasing state, and a state in which the magnetization directions of the first magnetism variable magnet 51 and the second magnetism variable magnet 52 face the second direction is referred to as a magnetization decreasing state.

[0072] 〈Auxiliary Magnet〉 In each of the plurality of magnetic pole portions 12, the first auxiliary magnet 61 and the second auxiliary magnet 62 are arranged symmetrically with respect to the d-axis.

[0073] 〈First Auxiliary Magnet〉 The first auxiliary magnet 61 is arranged between the magnetism fixed magnet 40 and the first magnetism variable magnet 51. The circumferential length between the first auxiliary magnet 61 and the magnetism fixed magnet 40 is shorter than the circumferential length between the first auxiliary magnet 61 and the first magnetism variable magnet 51.

[0074] The first auxiliary magnet 61 is embedded in the rotor core 11. In this example, the first auxiliary magnet 61 is accommodated in a first auxiliary magnet hole H61 provided in the rotor core 11. Also, the first auxiliary magnet 61 extends along one end portion in the circumferential direction of the magnetism fixed magnet 40. Specifically, the first auxiliary magnet 61 is formed with a rectangular cross-sectional shape, and the short side direction faces the longitudinal direction of the magnetism fixed magnet 40.

[0075] The first auxiliary magnet 61 is magnetized in a direction that inhibits the flow of magnetic flux between the radially outer end of the magnetic force fixing magnet 40 and the first magnetically variable magnet 51. Specifically, when the magnetization direction of the magnetic force fixing magnet 40 is a direction toward the radially outer side, the magnetization direction of the first auxiliary magnet 61 is a direction from the first magnetically variable magnet 51 toward the magnetic force fixing magnet 40. When the magnetization direction of the magnetic force fixing magnet 40 is a direction toward the radially inner side, the magnetization direction of the first auxiliary magnet 61 is a direction from the magnetic force fixing magnet 40 toward the first magnetically variable magnet 51.

[0076] 〈Second Auxiliary Magnet〉 The second auxiliary magnet 62 is disposed between the magnetic force fixing magnet 40 and the second magnetically variable magnet 52. The circumferential length between the second auxiliary magnet 62 and the magnetic force fixing magnet 40 is shorter than the circumferential length between the second auxiliary magnet 62 and the second magnetically variable magnet 52.

[0077] The second auxiliary magnet 62 is embedded in the rotor core 11. In this example, the second auxiliary magnet 62 is accommodated in a second auxiliary magnet hole H62 provided in the rotor core 11. Further, the second auxiliary magnet 62 extends along the circumferential other end of the magnetic force fixing magnet 40. Specifically, the second auxiliary magnet 62 has a rectangular cross-sectional shape, and the short side direction faces the longitudinal direction of the magnetic force fixing magnet 40.

[0078] The second auxiliary magnet 62 is magnetized in a direction that inhibits the flow of magnetic flux between the radially outer end of the magnetic force fixing magnet 40 and the second magnetically variable magnet 52. Specifically, when the magnetization direction of the magnetic force fixing magnet 40 is a direction toward the radially outer side, the magnetization direction of the second auxiliary magnet 62 is a direction from the second magnetically variable magnet 52 toward the magnetic force fixing magnet 40. When the magnetization direction of the magnetic force fixing magnet 40 is a direction toward the radially inner side, the magnetization direction of the second auxiliary magnet 62 is a direction from the magnetic force fixing magnet 40 toward the second magnetically variable magnet 52.

[0079] 〈Non-Magnetic Member〉 The first non-magnetic member 71 included in each of the plurality of magnetic pole portions 12 is adjacent to a second non-magnetic member 72 included in another magnetic pole portion 12 located on one end side in the circumferential direction of the magnetic pole portion 12 (adjacent in the clockwise direction in the examples of FIGS. 3 and 4), with the q-axis interposed therebetween.

[0080] In each of the plurality of magnetic pole portions 12, the first non-magnetic member 71 and the second non-magnetic member 72 are arranged symmetrically with respect to the d-axis. The first non-magnetic member 71 and the second non-magnetic member 72 are made of, for example, a resin having insulating properties.

[0081] 〈First non-magnetic member〉 The first non-magnetic member 71 is arranged at a position radially inside the magnetic force fixed magnet 40, the first magnetically variable magnet 51, and the first auxiliary magnet 61 on one end side in the circumferential direction of the magnetic pole portion 12. The first non-magnetic member 71 is separated from the radially inner ends of the magnetic force fixed magnet 40 and the first auxiliary magnet 61.

[0082] The first non-magnetic member 71 is embedded in the rotor core 11. In this example, the first non-magnetic member 71 is housed in a first housing hole H71 that is arranged adjacent to the first magnetically variable magnet 51 on the radially inner side. Also, the first non-magnetic member 71 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the cross-sectional shape of the first non-magnetic member 71 is formed in a trapezoidal shape. One hypotenuse of the first non-magnetic member 71 faces in a direction parallel to the q-axis, and the other hypotenuse of the first non-magnetic member 71 faces in a direction parallel to the d-axis.

[0083] In this example, the first non-magnetic member 71 is a member for holding the first magnetically variable magnet 51. Specifically, the first housing hole H71 communicates with the first magnetically variable magnet hole H51. The first non-magnetic member 71 has a protruding portion that protrudes toward the first magnetically variable magnet 51. And the first non-magnetic member 71 is housed in the first housing hole H71 in a state where the first magnetically variable magnet 51, in which the protruding portion thereof is housed in the first magnetically variable magnet hole H51, is pressed radially outward.

[0084] The first non-magnetic member 71 has a first void portion 71a. The first void portion 71a penetrates the first non-magnetic member 71 in the axial direction. The first void portion 71a is formed along the shape of the first housing hole H71. The first void portion 71a protrudes toward the first magnetically variable magnet 51 at the position of the first magnetically variable magnet 51 in the circumferential direction.

[0085] <Second non-magnetic member> The second non-magnetic member 72 is disposed at a position radially inside the magnetic force fixing magnet 40, the second magnetically variable magnet 52, and the second auxiliary magnet 62 on the other end side in the circumferential direction of the magnetic pole portion 12. The second non-magnetic member 72 is separated from the radially inner ends of the magnetic force fixing magnet 40 and the second auxiliary magnet 62.

[0086] The second non-magnetic member 72 is embedded in the rotor core 11. In this example, the second non-magnetic member 72 is accommodated in a second accommodation hole H72 disposed adjacent to the second magnetically variable magnet 52 on the radially inner side. Also, the second non-magnetic member 72 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the cross-sectional shape of the second non-magnetic member 72 is formed in a trapezoidal shape. One hypotenuse of the second non-magnetic member 72 faces a direction parallel to the q-axis, and the other hypotenuse of the second non-magnetic member 72 faces a direction parallel to the d-axis.

[0087] In this example, the second non-magnetic member 72 is a member for holding the second magnetically variable magnet 52. Specifically, the second accommodation hole H72 communicates with the second magnetically variable magnet hole H52. The second non-magnetic member 72 has a protruding portion that protrudes toward the second magnetically variable magnet 52. And the second non-magnetic member 72 is accommodated in the second accommodation hole H72 in a state where the protruding portion presses the second magnetically variable magnet 52 accommodated in the second magnetically variable magnet hole H52 radially outward.

[0088] The second non-magnetic member 72 has a second void portion 72a. The second void portion 72a penetrates the second non-magnetic member 72 in the axial direction. The second void portion 72a is formed along the shape of the second accommodation hole H72. The second void portion 72a protrudes toward the second magnetically variable magnet 52 at the position of the second magnetically variable magnet 52 in the circumferential direction.

[0089] <First non-magnetic conductor> A first non-magnetic conductor 73 is disposed in the first gap portion 71a. The cross-sectional shape of the first non-magnetic conductor 73 is L-shaped. The first non-magnetic conductor 73 has a first longitudinally extending portion 73a that is located on one circumferential end side of the magnetic force fixing magnet 40 and extends in a direction orthogonal to the circumferential direction (here, the radial direction) toward the first magnetically variable magnet 51. The first non-magnetic conductor 73 has a first laterally extending portion 73b that extends circumferentially from the first longitudinally extending portion 73a.

[0090] As shown in FIG. 5, the first non-magnetic conductor 73 extends axially along the first receiving hole H71. The first non-magnetic conductor 73 axially penetrates a pair of insulating sheets 13 and a pair of end plates 14 provided on both sides of the rotor core 11, respectively. Both axial end portions of the first non-magnetic conductor 73 are fixed to the pair of end plates 14, respectively.

[0091] As shown in FIGS. 3 to 5, the first non-magnetic conductor 73 is disposed with a gap from the inner peripheral surface of the first receiving hole H71. The width of the gap between the first non-magnetic conductor 73 and the inner peripheral surface of the first receiving hole H71 is greater than or equal to the circumferential width of the first magnetically variable magnet 51.

[0092] The first non-magnetic conductor 73 is made of a metal such as aluminum or copper. Although it will be described in detail later, the first non-magnetic conductor 73 generates eddy currents such that a magnetic flux repelling a predetermined magnetic flux is generated by a magnetic flux (hereinafter referred to as a predetermined magnetic flux) for changing the magnetization states of the first magnetically variable magnet 51 and the second magnetically variable magnet 52.

[0093] <Second Non-Magnetic Conductor> A second non-magnetic conductor 74 is disposed in the second gap portion 72a. The cross-sectional shape of the second non-magnetic conductor 74 is L-shaped. The second non-magnetic conductor 74 has a second longitudinally extending portion 74a that is located on one circumferential end side of the magnetic force fixing magnet 40 and extends in a direction orthogonal to the circumferential direction (here, the radial direction) toward the second magnetically variable magnet 52. The second non-magnetic conductor 74 has a second laterally extending portion 74b that extends circumferentially from the second longitudinally extending portion 74a.

[0094] Although illustration is omitted, the second non-magnetic conductor 74 extends axially along the second accommodation hole H72. The second non-magnetic conductor 74 axially penetrates through a pair of insulating sheets 13 and a pair of end plates 14 provided on both sides of the rotor core 11 respectively. Both axial end portions of the second non-magnetic conductor 74 are fixed to the pair of end plates 14 respectively.

[0095] As shown in FIGS. 3 and 4, the second non-magnetic conductor 74 is arranged with a gap from the inner peripheral surface of the second accommodation hole H72. The width of the gap between the second non-magnetic conductor 74 and the inner peripheral surface of the second accommodation hole H72 is larger than the circumferential width of the second magneto-variable magnet 52.

[0096] The second non-magnetic conductor 74 is made of a metal such as aluminum or copper. Although it will be described in detail later, the second non-magnetic conductor 74 generates eddy currents by a predetermined magnetic flux such that magnetic fluxes repelling the predetermined magnetic flux are generated.

[0097] 〔Control System of Driving Motor〕 In the automobile 1, in order to control its running according to the driver's operation, the above-described units of the ECU 91, MCU 92, TCU 93, and GCU 94 are installed. Each of these units is composed of hardware such as a processor, a memory, and an interface, and software such as a database and a control program. Each of these units is connected, for example, by CAN (Controller Area Network) and is configured to be able to communicate electrically with each other.

[0098] The ECU 91 is a unit mainly controlling the operation of the engine 3. The MCU 92 is a unit mainly controlling the operation of the driving motor 2. The TCU 93 is a unit mainly controlling the operation of the transmission 9. The GCU 94 is a higher-level unit electrically connected to these ECU 91, MCU 92, and TCU 93 and comprehensively controlling them.

[0099] The engine rotation sensor 81 is attached to the engine 3, detects the rotational speed of the engine 3, and outputs it to the ECU 91. The transmission sensor 82 detects the rotational speed and fastening torque of each transmission clutch, the rotational speed of the output shaft, etc., and outputs it to the TCU 93. The motor rotation sensor 83 is attached to the drive motor 2, detects the rotational speed and rotational position of the drive motor 2, and outputs it to the MCU 92. The magnetic force sensor 84 is attached to the drive motor 2, detects the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet, and outputs it to the MCU 92. The current sensor 85 is attached to the connection path (electric wire) between the drive motor 2 and the inverter 6, detects the current supplied to each coil 22, and outputs it to the MCU 92. The accelerator sensor 86 is attached to the accelerator pedal that the driver depresses when driving the vehicle 1, detects the accelerator opening corresponding to the output required for driving the vehicle 1, and outputs it to the ECU 91.

[0100] Based on the signals of the detection values input from these sensors, each unit controls each device of the drive system, and thus the vehicle 1 runs. For example, when the vehicle 1 runs with the driving force of the engine 3, the ECU 91 controls the operation of the engine 3 based on the detection values of the accelerator sensor 86 and the engine rotation sensor 81.

[0101] 〔Control of Drive Motor〕 As shown in FIG. 6, the MCU 92 includes a processor 92a and a memory 92b. Software such as a database and a control program is stored in the memory 92b. The control executed by the MCU 92 is executed by the processor 92a reading the software stored in the memory 92b.

[0102] The MCU 92 controls so that the vehicle 1 runs using the power output by the drive motor 2 in a state where the drive motor 2 outputs alone or, if necessary, assists the output of the engine 3.

[0103] Specifically, the ECU 91 sets the torque output by the engine 3 based on the detected values of the accelerator sensor 86, the engine speed sensor 81, etc. The GCU 94 sets the required torque (requested torque) for the drive motor 2 within a predetermined output range according to the preset output distribution ratio between the engine 3 and the drive motor 2. The MCU 92 controls the drive motor 2 so that the requested torque is output.

[0104] The MCU 92 controls the drive current flowing through the coil 22 to cause the drive motor 2 to output the required power.

[0105] The MCU 92 has a function of increasing the power factor of the drive motor 2, and changes the magnetic force of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 by controlling the magnetization current flowing through the coil 22. Specifically, the magnetic force of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 is changed so that the magnetic force of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 substantially coincides with the electromagnetic force generated in the coil 22 by the drive current.

[0106] The power factor is the ratio of the active power (the power actually consumed) to the apparent power (the power supplied to the drive motor 2). When the power factor is low, a large current needs to be passed to obtain the same output, so the motor becomes larger accordingly. Therefore, by increasing the power factor of the drive motor 2, the drive motor 2 can be made lightweight and compact. Also, if the power factor is increased, the generated power during regeneration can also be increased.

[0107] 〔Specific Example of Drive Motor Control〕 Fig. 7 shows a simplified system diagram regarding the control of the drive motor 2. Fig. 8 shows an example of the control of the drive motor 2 performed by the MCU 92. The specific control flow of the drive motor 2 will be described with reference to these. Note that the drive motor 2 is controlled by vector control using the torque current command Iq * and the excitation current command Id * and is controlled by vector control using the torque current command Iq and the excitation current command Id.

[0108] When the vehicle 1 becomes drivable, the MCU92 constantly receives detection values from the current sensor 85, the motor rotation sensor 83, and the magnetic force sensor 84 (step S1). Also, the ECU91 constantly receives detection values from the accelerator sensor 86 and the engine rotation sensor 81.

[0109] The GCU94 acquires the detection value of the accelerator sensor 86 and sets the torque required for the drive motor 2 (required torque) among the torques output to the drive wheels 4R according to a preset output distribution ratio between the engine 3 and the drive motor 2. The GCU94 outputs a command (torque command value T * ) for outputting the required torque to the MCU92.

[0110] In the MCU92, the output of the drive motor 2 is controlled based on a predetermined target torque (so-called torque control). By the torque control, the torque (motor torque) output by the drive motor 2 is controlled to match the target torque. Therefore, when the above command is input while the vehicle 1 is running, the MCU92 controls the drive motor 2 with the required torque as the target torque. By the torque control of the drive motor 2, the vehicle 1 runs according to the driver's request.

[0111] When this vehicle 1 is running, as described above, when shifting the magnetization region Rm, the torque control is interrupted and control for applying a high voltage to the coil 22 of the drive motor 2 is executed (magnetic force change control). By the magnetic force change control, the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet are changed.

[0112] Specifically, when the torque command value T * is input (Yes in step S2), the MCU92 executes arithmetic processing of a command (drive current command value Idq * ) that outputs the change amount of the drive current (torque current component) that generates the torque. Also, the MCU92 outputs a command (magnetization state command value Φ *) performs arithmetic processing (step S4). The MCU 92 outputs a command (magnetic force current command value Idq * corresponding to the change amount of the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 based on the magnetization state command value Φ * ).) and performs arithmetic processing (step S5).

[0113] The MCU 92 determines whether it is necessary to change the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 based on the calculated drive current command value Idq * and the magnetic force current command value Idq * (step S6). For example, as described above, when the required torque is output and the magnetization region Rm shifts to another magnetization region Rm, it is determined that it is necessary to change the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52. When the required torque is output and the device is located in the same magnetization region Rm, it is determined that it is not necessary to change the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52.

[0114] Then, when the MCU 92 determines that it is not necessary to change the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52, it determines whether the torque to be output is greater than the torque T1 at which the drive motor 2 runs idle (step S7). When the torque to be output is greater than the torque T1, the MCU 92 controls the drive motor 2 by normal vector control.

[0115] That is, the MCU 92 performs arithmetic processing on a command (voltage command value Vuvw * ) output for performing PWM control based on the detection values of the current sensor 85 and the motor rotation sensor 83 by current control. Then, a switching command value is calculated by PWM control (step S9).

[0116] The switching command value is output to the inverter 6 through the driver circuit, so that a plurality of switching elements are turned on and off inside the inverter 6. Thereby, a predetermined three-phase alternating current (driving current) is supplied to each coil group, and the driving motor 2 rotates with the required torque (step S10).

[0117] On the other hand, when the MCU 92 determines that it is necessary to change the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 (No in step S6), magnetic force change control is executed (step S11).

[0118] Also, even when the MCU 92 determines that it is not necessary to change the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52, if it is determined that the torque to be output is equal to or less than the torque T1 at which the driving motor 2 runs idle (No in step S7), magnetic force change control is executed (step S11).

[0119] That is, when the required amount of rotational power of the driving motor 2 becomes almost zero (zero), the magnetic forces of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 are changed to their initial states (reset). In the case of the automobile 1, for example, there may be a case where the accelerator pedal is suddenly depressed and the vehicle accelerates rapidly from an idling state or a stopped state.

[0120] In the case of the first magnetically variable magnet 51 and the second magnetically variable magnet 52, since the magnetic forces in the initial state are set high according to high load, by resetting the magnetic forces during idling operation, even when such a rapid acceleration occurs, the driving motor 2 can be driven appropriately.

[0121] 〔Magnetic Flux during Magnetic Force Change Control〕 When the MCU 92 executes magnetic force change control, a pulse current is supplied to the coil 22. When a pulse current is supplied to the coil 22, magnetic flux corresponding to the magnitude of the pulse power is input from the stator 20 toward the magnetic pole portion 12.

[0122] Since the first gap 71a and the second gap 72a are provided in each magnetic pole portion 12, the magnetic flux from the stator 20 is less likely to flow to the radially inner region of the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52 in the rotor core 11. Therefore, the magnetic flux from the stator 20 basically flows toward the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52.

[0123] However, the pulse current supplied to the coil 22 in the magnetic force change control is larger than the pulse current when controlling the rotation of the drive motor 2, and the generated magnetic flux (corresponding to the above-mentioned predetermined magnetic flux) is also relatively large. For this reason, during the magnetic force change control, the magnetic flux may enter the first gap 71a and the second gap 72a as shown in Fig. 9. When the magnetic flux enters the first gap 71a and the second gap 72a and passes through the first gap 71a and the second gap 72a, the magnetic flux toward the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52 decreases. As a result, the efficiency of changing the magnetized state of the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52 may deteriorate.

[0124] In contrast, in the first embodiment, a first non-magnetic conductor 73 is disposed in the first gap 71a, and a second non-magnetic conductor 74 is disposed in the second gap 72a. As shown in FIG. 10, when a magnetic flux enters the first gap 71a and the second gap 72a, the first non-magnetic conductor 73 and the second non-magnetic conductor 74 generate an eddy current due to the influence of the magnetic flux, and generate a magnetic flux that repels the magnetic flux (hereinafter, simply referred to as a repulsive magnetic flux). When a repulsive magnetic flux is generated, the magnetic flux from the stator 20 is less likely to enter the first gap 71a and the second gap 72a. This makes it easier for the magnetic flux to flow from the stator 20 to the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52, so that the magnetization state of the first magnetic force variable magnet 51 and the second magnetic force variable magnet 52 can be efficiently changed.

[0125] In addition, since a gap is provided between the first non-magnetic conductor 73 and the inner peripheral surface of the first accommodation hole H71 and between the second non-magnetic conductor 74 and the inner peripheral surface of the second accommodation hole H72, the magnetic flux when controlling the drive motor 2 by normal vector control (in the aforementioned steps S8 to S10) is less likely to affect the first non-magnetic conductor 73 and the second non-magnetic conductor 74. Therefore, the first non-magnetic conductor 73 and the second non-magnetic conductor 74 do not adversely affect the normal operation of the drive motor 2.

[0126] 〔Pulse Control〕 Here, when the magnetic flux penetrates into the first gap portion 71a and the second gap portion 72a and time elapses, the eddy currents in the first non-magnetic conductor 73 and the second non-magnetic conductor 74 decay. In a state where the eddy currents in the first non-magnetic conductor 73 and the second non-magnetic conductor 74 have decayed, for example, when the rotor 10 rotates counterclockwise, the magnetic flux passing through the first non-magnetic conductor 73 temporarily decreases, while the magnetic flux passing through the second non-magnetic conductor 74 temporarily increases. At this time, as shown in FIG. 11, since the second non-magnetic conductor 74 generates a repulsive magnetic flux due to the eddy current, the efficiency of changing the magnetization state of the second magnetically variable magnet 52 remains high. On the other hand, an eddy current in the direction opposite to the start of the magnetic force change control is generated in the first non-magnetic conductor 73, and a magnetic flux is generated along the flow of the magnetic flux from the stator 20 in the direction opposite to the repulsive magnetic flux. At this time, the efficiency of changing the magnetization state of the first magnetically variable magnet 51 may deteriorate.

[0127] Therefore, in the first embodiment, the MCU 92 does not make the waveform of the pulse current during the magnetic force change control a simple rectangular shape. Specifically, during the magnetic force change control, the MCU 92 executes pulse control to increase and decrease the current with a width smaller than the amplitude of the pulse current during the pulse period of the pulse current after the amplitude of the pulse current reaches the maximum value.

[0128] FIG. 12 shows an example of a current waveform when pulse control is performed. As shown in FIGS. 9 and 10, the MCU 92 starts applying a pulse current at time t0 when the direction of the magnetic flux to be input to the first magnetically variable magnet 51 and the second magnetically variable magnet 52 (indicated by the dashed arrow) coincides with the direction of the magnetic flux input from the stator 20, and at least one of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 is located at a position between the circumferentially adjacent teeth 21b.

[0129] After the amplitude of the pulse current reaches the maximum value, as shown in FIG. 11, the MCU 92 increases or decreases the pulse current at the timing when the rotor 10 rotates slightly. The amplitude of the pulse current and the frequency of increase and decrease are set according to the operating conditions of the drive motor 2. Specifically, in pulse control, the MCU 92 changes the amplitude of the pulse current and the frequency of increase and decrease in consideration of the target magnetization rate of the first magnetically variable magnet 51 and the second magnetically variable magnet 52, the rotational speed of the rotor 10, and the power supply voltage.

[0130] The target magnetization rate of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 affects the amplitude of the pulse current. Specifically, the amplitude of the pulse current is made larger when the target magnetization rate of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 is high than when it is low. The target magnetization rate is the magnetization rate in the magnetization direction and magnitude that is to be changed by magnetic force change control.

[0131] The rotational speed of the rotor 10 affects the amplitude of the pulse current. Specifically, when the rotational speed of the rotor 10 is high, the amplitude of the pulse current is larger compared to when the rotational speed is low. When the rotational speed of the rotor 10 is high, since the instantaneous change in the magnetic flux input from the stator 20 to the first non-magnetic conductor 73 and the second non-magnetic conductor 74 is large, the eddy currents generated in the first non-magnetic conductor 73 and the second non-magnetic conductor 74 become large. When the eddy currents become large, the magnetic flux generated by the eddy currents, particularly the magnetic flux in the direction that inhibits the input of magnetic flux to the first magneto-variable magnet 51 and the second magneto-variable magnet 52, also becomes large. For this reason, when the rotational speed of the rotor 10 is high, the amplitude of the pulse current is increased compared to when the rotational speed is low so that as large a magnetic flux as possible is input to the first magneto-variable magnet 51 and the second magneto-variable magnet 52. The rotational speed of the rotor 10 is detected from the motor rotation sensor 83.

[0132] The power supply voltage affects the frequency at which the pulse current increases and decreases. Specifically, when the power supply voltage is high, the frequency is higher compared to when the power supply voltage is low. When the frequency is higher, the current waveform can be changed finely according to the operating conditions of the drive motor 2. The power supply voltage is calculated from the detection result of the current sensor 85.

[0133] The MCU 92 terminates the application of the pulse at the timing (time t1 in FIG. 12) when the first magneto-variable magnet 51 and the second magneto-variable magnet 52 rotate from the position at time t0 to the position of the adjacent tooth 21b. The MCU 92 also increases and decreases the pulse current immediately before terminating the application of the pulse. The MCU 92 changes the amplitude and frequency of the pulse control in the first half and the second half of the pulse period. The efficiency of changing the magnetization state of the first magneto-variable magnet 51 may deteriorate in the first half of the pulse period, which is the timing when the rotor 10 rotates slightly from time t0 as shown in FIG. 11. For this reason, it is necessary to perform pulse control more finely (at a higher frequency) in the first half of the pulse period compared to the second half of the pulse period. Also, the current waveform during pulse control tends to have a smaller amplitude in the second half of the pulse period compared to the first half of the pulse period.

[0134] FIG. 13 shows the main process flow of magnetic force change control. When magnetic force change control is requested, the MCU 92 determines the direction of the magnetization process based on the magnetization state command value Φ * That is, it determines whether to execute a process of increasing the magnetic force of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 (magnetic flux increasing process), or a process of decreasing the magnetic force of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 (magnetic flux decreasing process). The MCU 92 further specifies the amount of change in the magnetic force that increases or decreases.

[0135] Then, based on the detected value of the motor rotation sensor 83, the MCU 92 determines whether the position of the rotor 10 relative to the stator 20 (position in the rotation direction) is at a position suitable for the magnetization process (step S21). When the rotor 10 is at the appropriate position, the MCU 92 detects the operating condition of the drive motor 2 (step S22) and sets the current waveform of the magnetization current (step S23). After setting the current waveform, the MCU 92 outputs the magnetization current (step S24). In the magnetic flux increasing process and the magnetic flux decreasing process, the direction of the magnetic force lines of the electromagnetic force is reversed.

[0136] The MCU 92 determines whether the magnetic force of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 is approximately the same as the magnetic force optimum value indicated by the magnetization state command value Φ * (step S25), and executes the magnetization change control until the magnetic force of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 becomes approximately the same as the magnetic force optimum value. When resetting the magnetic force of the first magnetically variable magnet 51 and the second magnetically variable magnet 52, the magnetization change control is executed until it becomes approximately the same as the initial magnetic force.

[0137] When the magnetic force of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 becomes approximately the same as the magnetic force optimum value or the initial magnetic force, the magnetic force change control is terminated, and as shown in FIG. 8, the drive motor 2 is controlled by normal vector control (steps S8 to S10).

[0138] 〔Effect of Embodiment 1〕 As described above, in the rotor 10 having the rotor structure of Embodiment 1, the first non-magnetic conductor 73 and the second non-magnetic conductor 74 are provided. The first non-magnetic conductor 73 and the second non-magnetic conductor 74 generate eddy currents such that a magnetic flux repelling the predetermined magnetic flux is generated by the predetermined magnetic flux that changes the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52. By generating a magnetic flux repelling the predetermined magnetic flux from the first non-magnetic conductor 73 and the second non-magnetic conductor 74, it becomes difficult for the magnetic flux from the stator 20 to enter the first air gap 71a and the second air gap 72a. Thereby, when changing the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52, the magnetic flux can be easily made to flow through the first magneto-variable magnet 51 and the second magneto-variable magnet 52. As a result, the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 can be efficiently changed.

[0139] Also, in the rotor 10 of the present Embodiment 1, the first non-magnetic conductor 73 has a first longitudinally extending portion 73a extending in a direction orthogonal to the circumferential direction toward the first magneto-variable magnet 51, and the second non-magnetic conductor 74 has a second longitudinally extending portion 74a extending in a direction orthogonal to the circumferential direction toward the second magneto-variable magnet 52. The first longitudinally extending portion 73a allows the first non-magnetic conductor 73 to approach the first magneto-variable magnet 51 as close as possible, and also allows the second non-magnetic conductor 74 to approach the second magneto-variable magnet 52. Thereby, the intrusion of the magnetic flux into the first air gap 71a and the second air gap 72a can be effectively suppressed, so that the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 can be efficiently changed.

[0140] Further, in the rotor 10 of the first embodiment, gaps are provided between the first non-magnetic conductor 73 and the inner peripheral surface of the first gap portion 71a, and between the second non-magnetic conductor 74 and the inner peripheral surface of the second gap portion 72a, respectively. As a result, when the magnetic flux from the stator 20 is relatively small, except when changing the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52, it becomes difficult for the magnetic flux to reach the first non-magnetic conductor 73 and the second non-magnetic conductor 74, and it becomes difficult for eddy currents to be generated. Thereby, it is possible to suppress the deterioration of the efficiency of the drive motor 2 due to the magnetic flux formed by the eddy currents in the first non-magnetic conductor 73 and the second non-magnetic conductor 74.

[0141] Further, in the first embodiment, the drive motor 2 is a radial gap motor in which the rotor 10 and the stator 20 are arranged with a gap in the radial direction, and further includes end plates 14 provided at both axial ends of the rotor 10, respectively. The first non-magnetic conductor 73 and the second non-magnetic conductor 74 are respectively fixed to the end plates 14. The first non-magnetic conductor 73 and the second non-magnetic conductor 74 can be used as reinforcing members of the end plates 14, and the strength of the rotor 10 can be improved.

[0142] Further, in the first embodiment, in the magnetic force change control for changing the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52, the MCU 92 executes pulse control to increase and decrease the current with a width smaller than the amplitude of the pulse current during the pulse period of the pulse current after the amplitude of the pulse current reaches the maximum value. By executing the pulse control, even if eddy currents that generate magnetic flux along the predetermined magnetic flux are generated in the first non-magnetic conductor 73 and the second non-magnetic conductor 74 as the rotor 10 rotates, the largest possible magnetic flux can be input to the first magneto-variable magnet 51 and the second magneto-variable magnet 52. Thereby, the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 can be changed more efficiently.

[0143] In particular, in the first embodiment, the MCU 92 changes the magnitude and number of increases and decreases (the amplitude of the pulse current and the frequency of increases and decreases) in pulse control in consideration of the magnetization rates of the first magnetically variable magnet 51 and the second magnetically variable magnet 52, the rotational speed of the rotor 10, and the power supply voltage. As a result, the magnetic flux input to the first magnetically variable magnet 51 and the second magnetically variable magnet 52 can be made as large as possible. Thereby, the magnetization states of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 can be changed more efficiently.

[0144] (Embodiment 2) Hereinafter, Embodiment 2 will be described in detail with reference to the drawings. In the following description, parts common to the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0145] The second embodiment is different from the first embodiment described above in that the drive motor 202 is an axial gap motor in which the rotor 210 and the stator 220 are arranged with a gap in the axial direction. The drive motor 202 is a two-rotor one-stator type motor in which one stator 220 is arranged between two rotors 210.

[0146] A shaft 230 is inserted through the centers of each rotor 210 and the stator 220. Each rotor 210 is fixed to the shaft 230. The stator 220 is connected to the shaft 230 via a bearing, and the stator 220 does not rotate even if the shaft 230 rotates. In the following description, the rotational axis direction or the axial direction represents the direction in which the rotational axis J extends. The radial direction represents the radial direction centered on the rotational axis J. The circumferential direction represents the direction around the rotational axis J. In the radial direction, the side far from the rotational axis J is referred to as the "outer radial side", and the side close to the rotational axis J is referred to as the "inner radial side". Also, the stator 220 side in the axial direction is referred to as the "inner axial side", and the side opposite to the stator 220 in the axial direction is referred to as the "outer axial side".

[0147] Regarding the control of the drive motor 202, it is the same as that in the aforementioned Embodiment 1. Also in this Embodiment 2, the MCU 92 executes pulse control during magnetic force change control.

[0148] 〔Stator〕 The stator 220 faces each rotor 210 with a gap in the axial direction. The stator 220 has a plurality of coil sets 222.

[0149] The plurality of coil sets 222 are arranged at equal intervals in the circumferential direction. The plurality of coil sets 222 are each constituted by winding a coil around a stator core. The stator core is formed of a laminate obtained by laminating steel plates made of an amorphous soft magnetic material. When the coil sets 222 are energized, magnetic fluxes are generated in the plurality of coil sets 222.

[0150] Similar to Embodiment 1, the magnetic fluxes generated in the plurality of coil sets 222 include a rotating magnetic flux for rotating each rotor 210 and a variable magnetic flux (predetermined magnetic flux) for changing the magnetization states of the first magneto-variable magnet 251 and the second magneto-variable magnet 252 described later.

[0151] By supplying an alternating current to the plurality of coil sets 222, a rotating magnetic flux is generated in the plurality of coil sets 222. Each rotor 210 rotates due to this rotating magnetic flux. Also, during the rotation (or stop) of each rotor 210, by supplying a predetermined current (for example, a pulse current larger than the alternating current for generating the rotating magnetic flux) to the plurality of coil sets 222 for a predetermined time, a variable magnetic flux is generated in the plurality of coil sets 222. The magnetization states of the first magneto-variable magnet 251 and the second magneto-variable magnet 252 described later change due to this variable magnetic flux.

[0152] 〔Rotor〕 Next, with reference to FIGS. 15 to 17, the rotor 210 will be described. The rotor 210 includes a rotor core 211, a plurality of magnetic pole portions 212, an insulating sheet 213, an end plate 214, an outer wall portion 215, an inner wall portion 217, and a holder 216. Note that since the two rotors 210 have a mirror-symmetric structure with respect to a plane perpendicular to the axial direction, in the following description, the configuration of one rotor 210 will be described in detail, and the description of the other rotor 210 will be omitted.

[0153] 〔Rotor Core〕 The rotor core 211 is formed in a columnar shape. For example, the rotor core 211 is a laminated core in which a plurality of electromagnetic steel sheets having a high magnetic permeability are laminated in the radial direction. A shaft hole H230 (see FIG. 17) through which the shaft 230 is inserted is formed at the center of the rotor core 11.

[0154] 〔Magnetic Pole Portion〕 The plurality of magnetic pole portions 212 are provided on the rotor core 211 and are arranged in the circumferential direction. Each of the plurality of magnetic pole portions 212 has a magnetic force fixed magnet 240, a first magnetic force variable magnet 251, and a second magnetic force variable magnet 252. In addition, each of the plurality of magnetic pole portions 212 has a first hole portion 271, a second hole portion 272, a first non-magnetic conductor 273, and a second non-magnetic conductor 274. In FIG. 15, in order to make the arrangement of each member easy to see, the magnetic force fixed magnet 240, the first magnetic force variable magnet 251, and the second magnetic force variable magnet 252 are shown in some of the magnetic pole portions 212, and the first hole portion 271, the second hole portion 272, the first non-magnetic conductor 273, and the second non-magnetic conductor 274 are shown in the other magnetic pole portions 212, but these are all provided in each magnetic pole portion 212.

[0155] The magnetic pole portions 212 adjacent to each other in the circumferential direction of the rotor 10 have different magnetic properties. Specifically, the magnetization directions of the magnetic force fixed magnets 240 are opposite to each other.

[0156] 〈Magnetic Force Fixed Magnet〉 The magnetic force fixing magnet 240 is embedded in the rotor core 211. The magnetic force fixing magnet 240 extends in a direction orthogonal to the axial direction (tangential direction). Specifically, the magnetic force fixing magnet 240 has a rectangular cross-sectional shape, with its longitudinal direction facing the tangential direction and its short side direction facing the axial direction. The magnetic force fixing magnet 240 is formed in a fan shape when viewed from the axial direction. The circumferential length of the magnetic force fixing magnet 240 is shorter towards the inner side in the radial direction. Since the material of the magnetic force fixing magnet 240 is the same as that in the aforementioned Embodiment 1, detailed description thereof is omitted.

[0157] 〈First magnet with variable magnetic force〉 The first magnet with variable magnetic force 251 is disposed on one end side in the circumferential direction of the magnetic force fixing magnet 240. The first magnet with variable magnetic force 251 faces the magnetic force fixing magnet 240 with a gap therebetween in the circumferential direction.

[0158] The first magnet with variable magnetic force 251 is embedded in the rotor core 211. The first magnet with variable magnetic force 251 extends along the axial direction. Specifically, the first magnet with variable magnetic force 251 has a rectangular cross-sectional shape, with its longitudinal direction facing the axial direction and its short side direction facing the tangential direction.

[0159] The first magnet with variable magnetic force 251 is formed in a fan shape when viewed from the axial direction. The circumferential length of the first magnet with variable magnetic force 251 is shorter towards the inner side in the radial direction. Since the material of the first magnet with variable magnetic force 251 is the same as that in the aforementioned Embodiment 1, detailed description thereof is omitted.

[0160] 〈Second magnet with variable magnetic force〉 The second magnet with variable magnetic force 252 is disposed on the other end side in the circumferential direction of the magnetic force fixing magnet 240. The second magnet with variable magnetic force 252 faces the magnetic force fixing magnet 240 with a gap therebetween in the circumferential direction.

[0161] The second magnet with variable magnetic force 252 is embedded in the rotor core 211. The second magnet with variable magnetic force 252 extends along the axial direction. Specifically, the second magnet with variable magnetic force 252 has a rectangular cross-sectional shape, with its longitudinal direction facing the axial direction and its short side direction facing the tangential direction.

[0162] The second magnetically variable magnet 252 is formed in a fan shape when viewed from the axial direction. The circumferential length of the second magnetically variable magnet 252 is shorter towards the inner side in the radial direction. Since the material of the second magnetically variable magnet 252 is the same as that in the aforementioned Embodiment 1, a detailed description thereof is omitted.

[0163] 〈First hole portion〉 The first hole portion 271 is disposed adjacent to the magnetically fixed magnet 240 and the first magnetically variable magnet 251 on the outer side in the axial direction at one end side in the circumferential direction of the magnetic pole portion 212. Specifically, the first hole portion 271 extends from a position on the outer side in the axial direction of the first magnetically variable magnet 251 and at one end side in the circumferential direction of the magnetically fixed magnet 240 towards the other end side in the circumferential direction to a position on the outer side in the axial direction of the magnetically fixed magnet 240.

[0164] The first hole portion 271 and the magnetically fixed magnet 240 are separated from each other in the axial direction and the circumferential direction. The first hole portion 271 and the first magnetically variable magnet 251 are separated from each other in the axial direction.

[0165] The first hole portion 271 penetrates the rotor core 211 in the radial direction. The circumferential length of the first hole portion 271 is shorter towards the inner side in the radial direction.

[0166] 〈Second hole portion〉 The second hole portion 272 is disposed adjacent to the magnetically fixed magnet 240 and the second magnetically variable magnet 252 on the outer side in the axial direction at the other end side in the circumferential direction of the magnetic pole portion 212. Specifically, the second hole portion 272 extends from a position on the outer side in the axial direction of the second magnetically variable magnet 252 and at the other end side in the circumferential direction of the magnetically fixed magnet 240 towards the one end side in the circumferential direction to a position on the outer side in the axial direction of the magnetically fixed magnet 240.

[0167] The second hole portion 272 and the magnetically fixed magnet 240 are separated from each other in the axial direction and the circumferential direction. The second hole portion 272 and the second magnetically variable magnet 252 are separated from each other in the axial direction.

[0168] The second hole portion 272 penetrates the rotor core 211 in the radial direction. The circumferential length of the second hole portion 272 is shorter towards the inner side in the radial direction.

[0169] <First non-magnetic conductor> Inside the first hole portion 271, a first non-magnetic conductor 273 is disposed. The cross-sectional shape of the first non-magnetic conductor 273 is L-shaped. The first non-magnetic conductor 273 has a first longitudinally extending portion 273a that is located on one end side in the circumferential direction from the magnetic force fixing magnet 240 and extends in a direction (here, the axial direction) orthogonal to the circumferential direction toward the first magnetically variable magnet 251. The first non-magnetic conductor 273 has a first laterally extending portion 273b that extends from the end portion outside the axial direction of the first longitudinally extending portion 273a toward the other end side in the circumferential direction.

[0170] As shown in FIG. 15, the first non-magnetic conductor 273 extends in the radial direction along the first hole portion 271. The first laterally extending portion 273b is shorter toward the inner side in the radial direction. As shown in FIG. 17, the end portion on the outer side in the radial direction of the first non-magnetic conductor 273 is fixed to the outer wall portion 215. The end portion on the inner side in the radial direction of the first non-magnetic conductor 273 is fixed to the inner wall portion 217.

[0171] The first non-magnetic conductor 273 is disposed with a gap from the inner peripheral surface of the first hole portion 271.

[0172] The first non-magnetic conductor 273 is made of a metal such as aluminum or copper. Also in the second embodiment, as in the first embodiment, the first non-magnetic conductor 273 generates an eddy current that generates a magnetic flux that repels a predetermined magnetic flux by a magnetic flux (predetermined magnetic flux) for changing the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252.

[0173] <Second non-magnetic conductor> Inside the second hole portion 272, a second non-magnetic conductor 274 is disposed. The cross-sectional shape of the second non-magnetic conductor 274 is L-shaped. The second non-magnetic conductor 274 has a second longitudinally extending portion 274a that is located on the other end side in the circumferential direction from the magnetic force fixing magnet 240 and extends in a direction (here, the axial direction) orthogonal to the circumferential direction toward the second magnetically variable magnet 252. The second non-magnetic conductor 274 has a second laterally extending portion 274b that extends from the end portion outside the axial direction of the second longitudinally extending portion 274a toward the one end side in the circumferential direction.

[0174] As shown in FIG. 15, the second non-magnetic conductor 274 extends radially along the second hole portion 272. The second laterally extending portion 274b is shorter toward the radially inner side. As shown in FIG. 17, the radially outer end of the second non-magnetic conductor 274 is fixed to the outer wall portion 215. The radially inner end of the second non-magnetic conductor 274 is fixed to the inner wall portion 217.

[0175] The second non-magnetic conductor 274 is arranged with a gap from the inner peripheral surface of the second hole portion 272.

[0176] The second non-magnetic conductor 274 is made of a metal such as aluminum or copper. Also in the second embodiment, as in the first embodiment, the second non-magnetic conductor 274 generates an eddy current that causes a magnetic flux repelling a predetermined magnetic flux by a magnetic flux (predetermined magnetic flux) for changing the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252.

[0177] 〔Insulating Sheet, End Plate〕 The insulating sheet 213 is arranged axially inside the rotor core 211. The insulating sheet 213 is disc-shaped and has a hole at the center through which the shaft 230 is inserted.

[0178] The end plate 214 is arranged axially outside the rotor core 211. The end plate 214 is disc-shaped and has a hole at the center through which the shaft 230 is inserted. The end plate 214 is fixed to the outer wall portion 215 and the inner wall portion 217.

[0179] 〔Outer Wall Portion, Inner Wall Portion〕 The outer wall portion 215 is arranged along the radially outer peripheral surface of the rotor core 211. The outer wall portion 215 is cylindrical. The outer wall portion 215 is arranged concentrically with the rotor core 211. The inner diameter of the outer wall portion 215 is equal to the outer diameter of the rotor core 211 or slightly larger than the outer diameter of the rotor core 211.

[0180] The inner wall portion 217 is arranged along the shaft hole H230 of the rotor core 211. The inner wall portion 217 is cylindrical. The inner wall portion 217 is arranged concentrically with the rotor core 211. The outer diameter of the inner wall portion 217 is equal to or slightly smaller than the diameter of the shaft hole H230. The inner diameter of the inner wall portion 217 is equal to the diameter of the shaft 230.

[0181] 〔Holder〕 The holder 216 is arranged on the inner side in the axial direction of the insulating sheet 213. The holder 216 has a ring 216a, a plurality of arc portions 216b, and a connecting portion 216c that connects the ring 216a and the plurality of arc portions 216b respectively.

[0182] The ring 216a is arranged at a position overlapping the inner wall portion 217 when viewed from the axial direction. The ring 216a is arranged concentrically with the rotor core 211. The outer diameter of the ring 216a is smaller than the outer diameter of the inner wall portion 217. The inner diameter of the ring 216a is larger than the inner diameter of the inner wall portion 217. The ring 216a is fixed to the inner wall portion 217.

[0183] The arc portion 216b is arranged at a position overlapping the outer wall portion 215 when viewed from the axial direction. The arc portion 216b is arranged concentrically with the rotor core 211. The arc portions 216b are arranged at equal intervals in the circumferential direction. The outer diameter of the arc portion 216b is equal to the outer diameter of the outer wall portion 215. The inner diameter of the arc portion 216b is equal to the inner diameter of the outer wall portion 215. The arc portion 216b is fixed to the outer wall portion 215.

[0184] The connecting portion 216c is arranged at a position overlapping the rotor core 211 when viewed from the axial direction. The connecting portion 216c extends straight in the radial direction. The radially outer end of the connecting portion 216c is located at the circumferential center of the arc portion 216b. The connecting portion 216c is fixed to the rotor core 211.

[0185] 〔Effect of Embodiment 2〕 As described above, in the second embodiment, the drive motor 202 is an axial-gap type motor. When the drive motor 202 operates, a centrifugal force is applied to the rotor 210. When a centrifugal force is applied to the rotor 210, the rotor core 211 attempts to move radially outward and presses the outer wall portion 215 radially outward. When the rotor core 211 presses the outer wall portion 215 radially outward, the outer wall portion 215 deforms. At this time, relatively large stresses are respectively input to the connection portion between the outer wall portion 215 and the end plate 214, the connection portion between the outer wall portion 215 and the holder 216, the connection portion between the inner wall portion 217 and the end plate 214, and the connection portion between the inner wall portion 217 and the holder 216.

[0186] In the second embodiment, the first non-magnetic conductor 273 and the second non-magnetic conductor 274 are fixed to the outer wall portion 215 and the inner wall portion 217, respectively. That is, the first non-magnetic conductor 273 and the second non-magnetic conductor 274 integrally connect the outer wall portion 215 and the inner wall portion 217. Thereby, even if the rotor core 211 presses the outer wall portion 215 radially outward, the deformation of the outer wall portion 215 is suppressed, so that the stress applied to each connection portion is reduced. As a result, the strength of the rotor 210 can be improved.

[0187] Further, in the rotor 210 having the rotor structure of the second embodiment, the first non-magnetic conductor 273 and the second non-magnetic conductor 274 are provided. The first non-magnetic conductor 273 and the second non-magnetic conductor 274 generate eddy currents such that a magnetic flux repelling the predetermined magnetic flux is generated by a predetermined magnetic flux that changes the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252. Thereby, the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252 can be efficiently changed.

[0188] Also, in the rotor 210 of the second embodiment, the first non-magnetic conductor 273 has a first longitudinally extending portion 273a that is located on one circumferential end side of the magnetic force fixing magnet 240 and extends in a direction orthogonal to the circumferential direction toward the first magnetically variable magnet 251, and the second non-magnetic conductor 274 has a second longitudinally extending portion 274a that is located on the other circumferential end side of the magnetic force fixing magnet 240 and extends in a direction orthogonal to the circumferential direction toward the second magnetically variable magnet 252. Thereby, the intrusion of magnetic flux into the first hole portion 271 and the second hole portion 272 can be effectively suppressed, so that the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252 can be efficiently changed.

[0189] Also, in the rotor 210 of the second embodiment, gaps are provided between the first non-magnetic conductor 273 and the inner peripheral surface of the first hole portion 271 and between the second non-magnetic conductor 274 and the inner peripheral surface of the second hole portion 272, respectively. Thereby, except when changing the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252, magnetic flux hardly acts on the first non-magnetic conductor 273 and the second non-magnetic conductor 274, and eddy currents hardly occur in the first non-magnetic conductor 273 and the second non-magnetic conductor 274. As a result, it is possible to suppress the deterioration of the efficiency of the drive motor 2.

[0190] (Other Embodiments) The technology disclosed herein is not limited to the foregoing embodiments, and substitutions are possible without departing from the gist of the claims.

[0191] In the first and second embodiments, the vehicle 1 is a hybrid vehicle having an engine 3. However, the vehicle 1 is not limited thereto, and may be an electric vehicle having only the drive motors 2 and 202 as drive sources.

[0192] In the first and second embodiments, the first non-magnetic conductors (73, 273) have the first longitudinally extending portions (73a, 273a) and the first laterally extending portions (73b, 273b), and the second non-magnetic conductors (74, 274) have the second longitudinally extending portions (74a, 274a) and the second laterally extending portions (74b, 274b). However, the first laterally extending portions (73b, 273b) and the second laterally extending portions (74b, 274b) are not limited thereto and may be omitted.

[0193] In Embodiments 1 and 2, corresponding to the first magneto-variable magnets 51 and 251 and the second magneto-variable magnets 52 and 252, two holes (first accommodation holes H71, second accommodation holes H72, first hollow portions 271, and second hollow portions 272) were provided. However, this is not restrictive, and there may be only one hole for the first magneto-variable magnets 51 and 251 and the second magneto-variable magnets 52 and 252 adjacent to each other in the circumferential direction. In this case, that is, a configuration may be adopted in which one hole is provided between the magnetically fixed magnets 40 and 240 adjacent to each other in the circumferential direction. In this case, the non-magnetic conductors may be provided in a number corresponding to the number of holes.

[0194] In Embodiments 1 and 2, two magneto-variable magnets, i.e., the first magneto-variable magnets 51 and 251 and the second magneto-variable magnets 52 and 252, were provided for each magnetic pole portion 12 and 212. However, this is not restrictive, and one common magneto-variable magnet may be provided for the magnetic pole portions 12 and 212 adjacent to each other in the circumferential direction. That is, a configuration may be adopted in which one magneto-variable magnet is provided between the magnetically fixed magnets 40 and 240 adjacent to each other in the circumferential direction. In this case, one hole may be provided in the region between the magnetically fixed magnets 40 and 240 adjacent to each other in the circumferential direction, and the non-magnetic conductors may be provided in a number corresponding to the number of holes.

[0195] In Embodiment 1, the first non-magnetic member 71 was disposed in the first accommodation hole H71, and the second non-magnetic member 72 was disposed in the second accommodation hole H72. However, this is not restrictive, and the first non-magnetic member 71 and the second non-magnetic member 72 may be omitted.

[0196] In Embodiment 1, the first non-magnetic member 71 and the first non-magnetic conductor 73 were disposed in the first accommodation hole H71, and the second non-magnetic member 72 and the second non-magnetic conductor 74 were disposed in the second accommodation hole H72. However, this is not restrictive, and the first non-magnetic conductor 73 and the second non-magnetic conductor 74 may be omitted, and the first non-magnetic member 71 and the second non-magnetic member 72 may be formed of non-magnetic conductors. In this case, the first non-magnetic member 71 corresponds to the first non-magnetic conductor, and the second non-magnetic member 72 corresponds to the second non-magnetic conductor 74.

[0197] In Embodiment 1, the first non-magnetic conductor 73 was disposed in the first void portion 71a, and the second non-magnetic conductor 74 was disposed in the second void portion 72a. However, the present invention is not limited to this, and the first void portion 71a and the second void portion 72a may be omitted, and the first non-magnetic conductor 73 may be molded with the resin-made first non-magnetic member 71, and the second non-magnetic conductor 74 may be molded with the resin-made second non-magnetic member 72. In this case, it is not necessary to fix the first non-magnetic conductor 73 and the second non-magnetic conductor 74 to the end plate 14.

[0198] In Embodiment 2, one stator 220 was sandwiched axially between two rotors 210. However, the present invention is not limited to this, and one rotor may be sandwiched axially between two stators. At this time, each magnetic pole portion of the rotor may be configured such that two magnetic pole portions 212 of the rotor 210 in Embodiment 2 are arranged to be mirror images with respect to a plane orthogonal to the axial direction.

[0199] In Embodiment 2, the first non-magnetic member and the second non-magnetic member as in Embodiment 1 were not provided. However, the present invention is not limited to this, and also in Embodiment 2, a first non-magnetic member may be disposed in the first hole portion 271, and a second non-magnetic member may be disposed in the second hole portion 272. In this case, it is preferable to form a gap between the first non-magnetic member and the first non-magnetic conductor 273, and between the second non-magnetic member and the second non-magnetic conductor 274.

[0200] The foregoing embodiments are merely illustrative, and the scope of the present disclosure should not be construed in a limiting sense. The scope of the present disclosure is defined by the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present disclosure.

Industrial Applicability

[0201] The technology disclosed herein is useful as a rotor structure of a rotating electrical machine and a control device of a rotating electrical machine.

Description of Reference Numerals

[0202] 10 Rotor 11 Rotor Core 12 Magnetic Pole Portion 14 End plate 20 Stator 21 Stator core 40 Magnet for magnetic fixation 51 First magnet with variable magnetic force 52 Second magnet with variable magnetic force 71a First gap 72a Second gap 73 First non-magnetic conductor 73a First longitudinally extending portion 74 Second non-magnetic conductor 74a Second longitudinally extending portion 210 Rotor 211 Rotor core 212 Pole portion 214 End plate 220 Stator 240 Magnet for magnetic fixation 251 First magnet with variable magnetic force 252 Second magnet with variable magnetic force 271 First hole portion (first hole) 272 Second hole portion (second hole) 273 First non-magnetic conductor 273a First longitudinally extending portion 274 Second non-magnetic conductor 274a Second longitudinally extending portion H71 First receiving hole (first hole) H72 Second receiving hole (second hole)

Claims

1. A rotor structure of a rotating electrical machine including a rotor having a rotor core and a stator having a stator core disposed with a gap from the rotor core, a plurality of magnetically variable magnets arranged side by side in the circumferential direction, each of which is capable of changing the magnetization state in the circumferential direction by a predetermined magnetic flux, a hole portion disposed adjacent to the magnetically variable magnet in the radial direction or the axial direction, a non-magnetic conductor disposed in the hole portion, and generating an eddy current such that a magnetic flux repelling the predetermined magnetic flux is generated by the predetermined magnetic flux, characterized in that it comprises the above.

2. In the rotor structure of the rotating electrical machine according to Claim 1, the non-magnetic conductor has a longitudinally extending portion extending in a direction orthogonal to the circumferential direction toward the magnetically variable magnet, characterized in that it is a rotor structure of a rotating electrical machine.

3. In the rotor structure of the rotating electrical machine according to Claim 1, a gap is provided between the non-magnetic conductor and the inner peripheral surface of the hole portion, characterized in that it is a rotor structure of a rotating electrical machine.

4. In the rotor structure of the rotating electrical machine according to Claim 3, the rotating electrical machine is a radial gap motor in which the rotor and the stator are disposed with a radial gap therebetween, further comprising end plates respectively provided at both axial ends of the rotor core, the hole portion is disposed adjacent to the magnetically variable magnet in the radial direction, the non-magnetic conductor is fixed to the end plates respectively, characterized in that it is a rotor structure of a rotating electrical machine.

5. In the rotor structure of the rotating electrical machine according to Claim 3, the rotating electrical machine is an axial gap motor in which the rotor and the stator are disposed with an axial gap therebetween, further comprising an inner wall portion provided inside the rotor core in the radial direction and an outer wall portion provided outside the rotor core in the radial direction, the hole portion is disposed adjacent to the magnetically variable magnet in the axial direction, the non-magnetic conductor is fixed to the inner wall portion and the outer wall portion respectively, characterized in that it is a rotor structure of a rotating electrical machine.

6. In the rotor structure of the rotating electrical machine according to Claim 1, the rotor core includes a plurality of magnetic pole portions arranged in the circumferential direction and having the magnetically variable magnets, each of the magnetic pole portions has a magnetically fixed magnet having a predetermined magnetic force, the magnetically variable magnet, a first magnetically variable magnet disposed on one circumferential end side of the magnetically fixed magnet in each of the magnetic pole portions, a second magnet with variable magnetic force disposed on the other end side in the circumferential direction of the magnet with fixed magnetic force in each of the magnetic pole portions; and having In two of the magnetic pole portions adjacent to each other in the circumferential direction, the first magnet with variable magnetic force in one of the magnetic pole portions and the second magnet with variable magnetic force in the other magnetic pole portion are adjacent to each other in the circumferential direction. A rotor structure of a rotating electrical machine, characterized in that.

7. In the rotor structure of the rotating electrical machine according to claim 6, The hole portion is a first hole portion provided in a region between the magnet with fixed magnetic force and the first magnet with variable magnetic force in each of the magnetic pole portions; a second hole portion provided in a region between the magnet with fixed magnetic force and the second magnet with variable magnetic force in each of the magnetic pole portions; and having A rotor structure of a rotating electrical machine, characterized in that non-magnetic conductors are disposed in each of the first hole portion and the second hole portion.

8. A control device for a rotating electrical machine having the rotor structure according to claims 1 to 7, comprising a control unit that controls a pulse current for generating the predetermined magnetic flux, The control unit performs pulse control to increase and decrease the current with a width smaller than the amplitude of the pulse current during the pulse period of the pulse current after the amplitude of the pulse current reaches the maximum value. A control device for a rotating electrical machine, characterized in that.

9. In the control device for a rotating electrical machine according to claim 8, The control unit changes the magnitude and number of times of increasing and decreasing the current in the pulse control in consideration of the magnetization rate of the magnet with variable magnetic force, the rotational speed of the rotor, and the power supply voltage. A control device for a rotating electrical machine, characterized in that.

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