Rotor structure of rotary electric machine

Abstract

To reduce the noise generated via a rotary electric machine.SOLUTION: A rotor 10 comprises a plurality of reinforcement rods 73 arranged in a row in the circumferential direction penetrating a rotor core 11 in the axial or radial direction. The rotor core 11 includes a first hole 71 and a second hole 72 provided by being spaced apart in the circumferential direction, and the reinforcement rods 73 are respectively arranged so as to penetrate the first hole 71 and the second hole 72 by being spaced apart from the inner circumferential surfaces of the first hole 71 and the second hole 72. The reinforcement rods 73 include a first air passage 81 penetrating the inside of a reinforcement rod 73 in the axial direction of the reinforcement rod 73 and which air passes through, and a plurality of communication holes 85 for communicating the first air passage 81 with the first hole 71 and the second hole 72.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Conventionally, in order to reinforce a rotor, a structure has been known in which a plurality of rods penetrating through the rotor core are provided.

[0003] For example, in Patent Document 1, there is known a rotor structure including a rotor core, a conductor bar (rod) penetrating through the rotor core in the axial direction of the central axis of the rotor core, an annular end ring provided at an end of the rotor core and connected to the conductor bar protruding from the end, and an annular first reinforcing member provided between the rotor core and the end ring and in contact with the end ring, and an insertion hole into which the conductor bar protruding from the end is inserted is formed in the first reinforcing member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a hybrid vehicle having both a rotating electrical machine and an engine, vibrations generated by the engine may be transmitted to the rotating electrical machine and cause noise to be generated by leaking outside the vehicle from the rotating electrical machine. Even in an electric vehicle having no engine and only a rotating electrical machine, vibrations generated by the transmission may pass outside the vehicle through the rotating electrical machine and cause noise to be generated.

[0006] The technology disclosed herein has been made in view of such points, and the object thereof is to suppress noise generated through a rotating electrical machine.

Means for Solving the Problem

[0007] 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 fixed to a shaft, and a stator having a stator core disposed with a gap from the rotor core. The rotor core includes a plurality of rods penetrating in the axial direction or the radial direction and arranged side by side in the circumferential direction. The rotor core has a plurality of hole portions provided at intervals in the circumferential direction. The rods are respectively arranged so as to penetrate the hole portions with a gap between the rods and the inner peripheral surface of the hole portions. Further, each rod has a first air passage penetrating in the axial direction of the rod and through which air passes, and a plurality of communication holes communicating the air passage with the hole portions.

[0008] In the first aspect, a Helmholtz resonator is constituted by the first air passage, the communication holes, and the hole portions. By the Helmholtz resonator, vibrations of a frequency corresponding to the resonance frequency of the Helmholtz resonator among the vibrations input to the rotating electrical machine can be absorbed. Thereby, the noise generated through the rotating electrical machine can be suppressed.

[0009] A second aspect of the technology disclosed herein is, in the first 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, the rod penetrates the rotor core in the axial direction, and the first air passage penetrates the rod so as to communicate one end side and the other end side in the axial direction of the rotor.

[0010] In the second aspect, a Helmholtz resonator can be formed with a simple configuration, and the noise generated through the rotating electrical machine can be suppressed.

[0011] A third aspect of the technology disclosed herein is that, in the second aspect, the hole portion has a partition wall that partitions the hole portion in the axial direction, the rod is disposed so as to penetrate the partition wall, the communication holes are formed in respective portions of the rod located in respective spaces partitioned by the partition wall, and the spaces partitioned by the partition wall have different volumes from each other.

[0012] In the third aspect, since the hole portion is divided into a plurality of spaces with different volumes, Helmholtz resonators corresponding to a plurality of frequencies can be formed. Thereby, the noise generated via the rotating electrical machine can be suppressed.

[0013] A fourth aspect of the technology disclosed herein is that, in the first 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, the shaft has a second air passage extending axially inside the shaft, the rod penetrates the rotor core in the radial direction, and the first air passage penetrates the rod so as to communicate the second air passage with the outside of the rotor.

[0014] Vibration is likely to be input to the rotating electrical machine via the shaft. In the fourth aspect, by forming a second air passage in the shaft and communicating it with the first air passage, vibration is likely to be transmitted to the rod, and the sound absorption efficiency can be improved. Thereby, the noise generated via the rotating electrical machine can be suppressed.

[0015] A fifth aspect of the technology disclosed herein is that, in the fourth aspect, there are a plurality of types of the rods, and the diameter of the communication holes formed in one type of the rods is different from the diameter of the communication holes formed in the other type of the rods.

[0016] In the fifth aspect, by having different diameters of the communication holes, Helmholtz resonators corresponding to a plurality of frequencies can be formed. Thereby, the noise generated via the rotating electrical machine can be suppressed.

[0017] The sixth aspect of the technology disclosed herein is that, in the fourth aspect, the hole portion has a partition wall that partitions the hole portion in the radial direction, the rod is disposed through the partition wall, the communication hole is formed in each portion of the rod located in each space partitioned by the partition wall, and the volumes of the spaces partitioned by the partition wall are different from each other.

[0018] In the sixth aspect, since the hole portion is divided into a plurality of spaces with different volumes, Helmholtz resonators corresponding to a plurality of frequencies can be formed. Thereby, the noise generated via the rotating electrical machine can be suppressed.

Advantages of the Invention

[0019] As described above, according to the technology disclosed herein, by configuring a Helmholtz resonator with the first air passage, the communication hole, and the hole portion, vibrations of a frequency corresponding to the resonance frequency of the Helmholtz resonator can be absorbed, and the noise generated via the rotating electrical machine can be suppressed.

Brief Description of the Drawings

[0020]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10

Fig. 11

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

[0022] (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. As a drive source of the automobile, an engine 3 is mounted together with a drive motor 2 (magnetic force variable motor) to which the disclosed technology is applied. These cooperate to rotationally drive two wheels (drive wheels 4R) symmetrically located among the four wheels 4F, 4F, 4R, 4R. Thereby, the automobile 1 moves (runs). This automobile 1 is a hybrid vehicle capable of traveling using electric power. Note that the automobile 1 may be an electric vehicle equipped only with the drive motor 2. The automobile 1 may also be four-wheel drive.

[0023] In the case of this automobile 1, the engine 3 is disposed on the front side of the vehicle body, and the drive wheels 4R are disposed on the rear side of the vehicle body. That is, this automobile 1 is a so-called FR vehicle. In the case of this automobile 1, the engine 3 is the main drive source 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.

[0024] The engine 3 is an internal combustion engine that burns gasoline as fuel, for example. The engine 3 may be a diesel engine that uses light oil as fuel. The drive motor 2 is connected behind the engine 3 via the first clutch 5. The drive motor 2 is a permanent magnet synchronous motor driven by three-phase alternating current.

[0025] 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 and 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. Details of the drive motor 2 will be described later.

[0026] 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 currents with different phases and supplies it to the drive motor 2. Thereby, the drive motor 2 rotates.

[0027] 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 a propeller shaft.

[0028] The differential gear is connected to the left and right drive wheels 4R via a pair of drive shafts. When the automobile 1 is running (during power running), the rotational power shifted by the transmission 9 is distributed by the differential gear and transmitted to each drive wheel 4R.

[0029] When the vehicle 1 decelerates (during regeneration), energy consumed 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.

[0030] 〈Configuration of Drive Motor〉 Figure 2 shows a cross-section of the drive motor 2. As shown in Figure 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 or more.

[0031] 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".

[0032] 〔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.

[0033] The stator core 21 has an annular back yoke 21a and a plurality (nine) of teeth 21b that radially protrude inward in the radial direction from the back yoke 21a. For example, the stator core 21 is a laminated core formed by laminating a plurality of electromagnetic steel sheets having high magnetic permeability in the rotational axis direction.

[0034] The plurality of coils 22 are wound around the plurality of teeth 21b. When the plurality of coils 22 are energized, magnetic fluxes are 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.

[0035] In this example, the magnetic fluxes generated in the plurality of coils 22 include a rotating magnetic flux for rotating the rotor 10 and a variable magnetic flux (a predetermined magnetic flux) for changing the magnetization states of the first magneto-variable magnet 51 and the second magneto-variable magnet 52 described later.

[0036] 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. Further, during the rotation (or stop) of the rotor 10, 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 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.

[0037] 〔Rotor〕 Next, with reference to FIGS. 2 and 3, the rotor 10 will be described. The rotor 10 includes a rotor core 11 and a plurality of magnetic pole portions 12.

[0038] 〔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 at the center of the rotor core 11. A shaft 30 is inserted and fixed in the shaft hole.

[0039] 〔Magnetic Pole Portion〕 The plurality of magnetic pole portions 12 are provided on the rotor core 11 and are arranged side by side in the circumferential direction. Each of the plurality of magnetic pole portions 12 has a magnetic force fixed magnet 40, a first magneto-variable magnet 51, a second magneto-variable magnet 52, a first auxiliary magnet 61, and a second auxiliary magnet 62.

[0040] The magnetic pole portions 12 adjacent to each other in the circumferential direction of the rotor 10 have different magnetic properties from each other. Specifically, the magnetization directions of the magnetic force fixing magnet 40, the first auxiliary magnet 61, and the second auxiliary magnet 62 are opposite to each other.

[0041] 〈Magnetic force fixing magnet〉 The magnetic force fixing magnet 40 is embedded in the rotor core 11. In this example, the magnetic force fixing magnet 40 is accommodated in a magnetic force fixing magnet hole H40 provided in the rotor core 11. Further, the magnetic force fixing magnet 40 extends in a direction orthogonal to the radial direction (tangential direction). Specifically, the magnetic force fixing magnet 40 has a rectangular cross-sectional shape and its longitudinal direction faces the tangential direction.

[0042] For the magnetic force fixing 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 fixing magnet 40 substantially does not 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 can be output by the battery 7 and the inverter 6, is applied. The coercive force of the magnetic force fixing 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 fixing magnets 40 may be made of different magnetic materials, but in this rotor 10, the same magnetic material is used.

[0043] 〈Magnetic force variable magnet〉 The first magnetic force variable magnets 51 respectively included in the plurality of magnetic pole portions 12 are adjacent to the second magnetic force variable magnets 52 included in other magnetic pole portions 12 adjacent to one end side in the circumferential direction of the magnetic pole portion 12 (adjacent in the clockwise direction in FIGS. 2 and 3) with the q-axis interposed 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.

[0044] Also, in each of the plurality of magnetic pole portions 12, the first magnetic force variable magnet 51 and the second magnetic force variable magnet 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 magnetic force fixing magnet 40 and extends in the radial direction.

[0045] 〈First magnetic force variable magnet〉 The first magnetically variable magnet 51 is disposed on one end side in the circumferential direction of the magnetically fixed magnet 40. The first magnetically variable magnet 51 faces the magnetically fixed magnet 40 with a gap therebetween in the circumferential direction. The circumferential length between the first magnetically variable magnet 51 and the q-axis is shorter than the circumferential length between the first magnetically variable magnet 51 and the magnetically fixed magnet 40.

[0046] The first magnetically variable magnet 51 is embedded in the rotor core 11. In this example, the first magnetically variable magnet 51 is accommodated in a first magnetically variable magnet hole H51 provided in the rotor core 11. Further, the first magnetically variable magnet 51 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the first magnetically variable magnet 51 has a rectangular cross-sectional shape and its longitudinal direction faces a direction parallel to the q-axis.

[0047] 〈Second magnetically variable magnet〉 The second magnetically variable magnet 52 is disposed on the other end side in the circumferential direction of the magnetically fixed magnet 40. The second magnetically variable magnet 52 faces the magnetically fixed magnet 40 with a gap therebetween in the circumferential direction. The circumferential length between the second magnetically variable magnet 52 and the q-axis is shorter than the circumferential length between the second magnetically variable magnet 52 and the magnetically fixed magnet 40.

[0048] The second magnetically variable magnet 52 is embedded in the rotor core 11. In this example, the second magnetically variable magnet 52 is accommodated in a second magnetically variable magnet hole H52 provided in the rotor core 11. Further, the second magnetically variable magnet 52 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the second magnetically variable magnet 52 has a rectangular cross-sectional shape and its longitudinal direction faces a direction parallel to the q-axis.

[0049] 〈Magnetic characteristics of the magnetically variable magnet〉 For the first magnetically variable magnet 51 and the second magnetically 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 magnetically variable magnet 51 and the second magnetically variable magnet 52 can have its magnetic force changed by a predetermined magnetic flux, for example, a magnetic flux generated by a large current (e.g., 750 Arms) that the battery 7 and the inverter 6 can output. The first magnetically variable magnet 51 and the second magnetically variable magnet 52 are hardly magnetized when the current is at the level for normally driving the drive motor 2. At this time, the first magnetically variable magnet 51 and the second magnetically variable magnet 52 also function as permanent magnets.

[0050] In this example, the easy magnetization direction of each of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 faces the circumferential direction, more specifically, the direction orthogonal to the radial direction (tangential direction). The difficult magnetization direction of the first magnetically variable magnet 51 faces the direction orthogonal to the easy magnetization direction of the first magnetically variable magnet 51 (the radial direction in this example). The difficult magnetization direction of the second magnetically variable magnet 52 faces the direction orthogonal to the easy magnetization direction of the second magnetically variable magnet 52 (the radial direction in this example).

[0051] Also, in this example, each of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 can be switched between a state where the magnetization direction faces the first direction, a state where the magnetization direction faces the second direction, and a zero state where the magnetic force is substantially zero. The first direction is the direction in which the magnetic flux (effective magnetic flux) linking with the teeth 21b increases. The second direction is the direction in which the magnetic flux (effective magnetic flux) linking with the teeth 21b decreases. For example, when the magnetization direction of the magnetic force fixing magnet 40 is the direction facing outward in the radial direction, the first direction is the direction from the first magnetically variable magnet 51 (or the second magnetically variable magnet 52) toward the magnetic force fixing magnet 40, and the second direction is the direction from the magnetic force fixing magnet 40 toward the first magnetically variable magnet 51 (or the second magnetically variable magnet 52).

[0052] 〈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.

[0053] 〈First Auxiliary Magnet〉 The first auxiliary magnet 61 is disposed between the magnetic force fixing magnet 40 and the first magnetically variable magnet 51. The circumferential length between the first auxiliary magnet 61 and the magnetic force fixing magnet 40 is shorter than the circumferential length between the first auxiliary magnet 61 and the first magnetically variable magnet 51.

[0054] 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 circumferential end portion of the magnetic force fixing magnet 40. Specifically, the first auxiliary magnet 61 has a rectangular cross-sectional shape, and the short side direction faces the longitudinal direction of the magnetic force fixing magnet 40.

[0055] 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.

[0056] 〈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.

[0057] 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. Also, the second auxiliary magnet 62 extends along the other circumferential end portion 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.

[0058] 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 in the radially outward direction, the magnetization direction of the second auxiliary magnet 62 is in the 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 in the radially inward direction, the magnetization direction of the second auxiliary magnet 62 is in the direction from the magnetic force fixing magnet 40 toward the second magnetically variable magnet 52.

[0059] 〈Hole portion〉 The first hole portion 71 included in each of the plurality of magnetic pole portions 12 is adjacent to the second hole portion 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.

[0060] In each of the plurality of magnetic pole portions 12, the first hole portion 71 and the second hole portion 72 are arranged symmetrically with respect to the d-axis. The first hole portion 71 and the second hole portion 72 suppress the magnetic flux from the stator 20 from entering radially inside the first magnetically variable magnet 51 and the second magnetically variable magnet 52, and facilitate the inflow of magnetic flux into the first magnetically variable magnet 51 and the second magnetically variable magnet 52.

[0061] 〈First hole portion〉 The first hole portion 71 is arranged at a position radially inside the magnetic force fixing 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 hole portion 71 is separated from the radially inner ends of the magnetic force fixing magnet 40 and the first auxiliary magnet 61.

[0062] The first hole portion 71 penetrates the rotor core 11 in the axial direction. Further, the first hole portion 71 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the cross-sectional shape of the first hole portion 71 is formed in a trapezoidal shape. One hypotenuse of the first hole portion 71 faces in a direction parallel to the q-axis, and the other hypotenuse of the first hole portion 71 faces in a direction parallel to the d-axis.

[0063] As shown in Fig. 4, in the first hole portion 71, a first partition wall 71a that divides the first hole portion 71 into two spaces is formed. The first partition wall 71a is disposed at a position shifted to one axial side with respect to the axial center of the first space portion 71. The spaces partitioned by the first partition wall 71a have different volumes from each other. Specifically, the first partition wall 71a partitions the first hole portion 71 into a large space 71b with a relatively large volume and a small space 71c with a relatively small volume. Note that a plurality of first partition walls 71a may be provided in the first hole portion 71. In this case, the plurality of first partition walls 71a partition the first hole portion 71 such that the volumes of the plurality of spaces formed by the partitioning are different from each other.

[0064] 〈Second Hole Portion〉 The second hole portion 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 hole portion 72 is separated from the radially inner ends of the magnetic force fixing magnet 40 and the second auxiliary magnet 62.

[0065] The second hole portion 72 penetrates the rotor core 11 in the axial direction. Further, the second hole portion 72 extends along the q-axis (adjacent q-axes in the circumferential direction). Specifically, the cross-sectional shape of the second hole portion 72 is formed in a trapezoidal shape. One hypotenuse of the second hole portion 72 faces a direction parallel to the q-axis, and the other hypotenuse of the second hole portion 72 faces a direction parallel to the d-axis.

[0066] As shown in FIG. 4, in the second hole portion 72, a second partition wall 72a that divides the second hole portion 72 into two spaces is formed. The second partition wall 72a is disposed at a position shifted to one axial side with respect to the axial center of the second space portion 72. The volumes of the spaces partitioned by the second partition wall 72a are different from each other. Specifically, the second partition wall 72a divides the second hole portion 72 into a large space 72b with a relatively large volume and a small space 72c with a relatively small volume. Note that a plurality of second partition walls 72a may be provided in the second hole portion 72. In this case, the plurality of second partition walls 72a partition the second hole portion 72 such that the volumes of the plurality of spaces formed by the partitioning are different from each other.

[0067] 〔End Plate, Insulating Sheet〕 As shown in FIG. 5, a first end plate 13 is disposed on one axial end side of the rotor core 11. A second end plate 14 is disposed on the other axial end side of the rotor core 11. The outer diameters of the first end plate 13 and the second end plate 14 are equal to the outer diameter of the rotor core 11. A shaft 30 is inserted through the centers of the first end plate 13 and the second end plate 14.

[0068] A first insulating sheet 15 is disposed between the first end plate 13 and the rotor core 11. A second insulating sheet 16 is disposed between the second end plate 14 and the rotor core 11. The outer diameters of the first insulating sheet 15 and the second insulating sheet 16 are equal to the outer diameter of the rotor core 11. A shaft 30 is inserted through the centers of the first insulating sheet 15 and the second insulating sheet 16.

[0069] 〔Reinforcing Rod〕 Reinforcing rods 73 are respectively disposed at the positions of the first hole portion 71 and the second hole portion 72 in the circumferential direction. The reinforcing rod 73 is a member for improving the strength of the rotor 10. The reinforcing rod 73 penetrates the rotor core 11 in the axial direction. The reinforcing rods 73 are arranged side by side in the circumferential direction.

[0070] As shown in Fig. 5, the reinforcing rod 73 includes a head portion 73a, a shaft portion 73b, and a threaded portion 73c. The head portion 73a is disposed on one end side of the shaft portion 73b, and the threaded portion 73c is formed on the other end side of the shaft portion 73b. The head portion 73a, the shaft portion 73b, and the threaded portion 73c are concentric. The head portion 73a has a larger diameter than the shaft portion 73b.

[0071] As shown in Fig. 4, the reinforcing rod 73 is disposed so as to penetrate the first hole portion 71 and the second hole portion 72 with a gap between the inner peripheral surfaces of the first hole portion 71 and the second hole portion 72. Specifically, at the position of the first hole portion 71, the reinforcing rod 73 penetrates the first end plate 13 and the first insulating sheet 15 and enters the first hole portion 71. After passing through the first hole portion 71, the reinforcing rod 73 penetrates the second insulating sheet 16. The threaded portion 73c of the reinforcing rod 73 is connected to the second end plate 14 by screwing. On the other hand, the head portion 73a of the reinforcing rod 73 is located on the one end side in the axial direction of the first end plate 13 without penetrating the first end plate 13. The head portion 73a is accommodated in a recess 13a provided in the first end plate 13. Thereby, the reinforcing rod 73 is connected and fixed to the first end plate 13 and the second end plate 14. In a state where the reinforcing rod 73 is fixed to the first end plate 13 and the second end plate 14, the head portion 73a is flush with the first end plate 13. As shown in Fig. 4, the reinforcing rod 73 disposed at the position of the second hole portion 72 has the same configuration.

[0072] The reinforcing rod 73 is made of a non-magnetic conductor such as aluminum or copper. When magnetic flux for changing the magnetization states of the first magnetically variable magnet 51 and the second magnetically variable magnet 52 is input, the reinforcing rod 73 generates eddy currents that generate repulsive magnetic fluxes that repel the magnetic flux. Due to the repulsive magnetic flux, it becomes difficult for the magnetic flux to enter through the first hole portion 71 and the second hole portion 72, so that the magnetic flux can be made to flow easily toward the first magnetically variable magnet 51 and the second magnetically variable magnet 52.

[0073] 〔Air passage〕 Each reinforcing rod 73 has an air passage 81 through which air passes. The air passage 81 penetrates through the inside of the reinforcing rod 73 in a first specific direction which is the axial direction of the reinforcing rod 73. That is, the air passage 81 penetrates through the head portion 73a, the shaft portion 73b, and the threaded portion 73c along the first specific direction. The air passage 81 communicates the one axial end side and the other end side of the rotor 10. The first specific direction is parallel to the axial direction of the shaft 30.

[0074] The shaft portion 73b is provided with a plurality (six in FIGS. 4 and 5) of communication holes 85 that communicate the air passage 81 with the first hole portion 71 and the second hole portion 72. The communication holes 85 are arranged side by side in the first specific direction and are arranged to face each other in a second specific direction orthogonal to the first specific direction. The communication holes 85 are formed in each of the portions of the reinforcing rod 73 located in the large spaces 71b, 72b and the portions located in the small spaces 71c, 72c. The communication holes 85 are not formed in the portions of the reinforcing rod 73 located in the first partition wall 71a and the second partition wall 72a.

[0075] Here, in a hybrid vehicle such as the automobile 1, vibrations generated by the engine 3 may be transmitted to the drive motor 2 and may generate noise by escaping from the drive motor 2 to the outside of the vehicle. In addition, vibrations when the gears of the transmission 9 change may escape to the outside of the vehicle via the drive motor 2 and generate noise.

[0076] On the other hand, in the rotor 10 according to the first embodiment, a Helmholtz resonator is constituted by the air passage 81, the communication holes 85, and the first hole portion 71 and the second hole portion 72. The Helmholtz resonator can absorb vibrations having a frequency corresponding to the resonance frequency of the Helmholtz resonator among the vibrations input to the drive motor 2. Thereby, the noise generated via the drive motor 2 can be suppressed.

[0077] The resonance frequency is expressed by the following formula

[0078]

Equation

[0079] v is the speed of sound, V is the volume of the large space 71b, 72b or the small space 71c, 72c, L is the length of the communication hole 85, and S is the opening area of the communication hole 85.

[0080] 〔Effect of Embodiment 1〕 As described above, in the rotor 10 having the rotor structure of Embodiment 1, a plurality of reinforcing rods 73 that penetrate the rotor core 11 in the axial direction and are arranged side by side in the circumferential direction are provided. The rotor core 11 has a plurality of first hole portions 71 and second hole portions 72 provided at intervals in the circumferential direction, and the reinforcing rods 73 are respectively arranged so as to penetrate the first hole portion 71 and the second hole portion 72 with a gap between the inner peripheral surface of the first hole portion 71 and the inner peripheral surface of the second hole portion 72. The reinforcing rod 73 has an air passage 81 that penetrates through the inside of the reinforcing rod 73 in a first specific direction that is the axial direction of the reinforcing rod and through which air passes, and a plurality of communication holes 85 that communicate the air passage 81 with the first hole portion 71 and the second hole portion 72. Thereby, a Helmholtz resonator is configured by the air passage 81, the communication holes 85, the first hole portion 71, and the second hole portion 72. With the Helmholtz resonator, among the vibrations input to the drive motor 2, vibrations having a frequency corresponding to the resonance frequency of the Helmholtz resonator can be absorbed. Thereby, the noise generated via the drive motor 2 can be suppressed.

[0081] Further, in the present Embodiment 1, the reinforcing rod 73 penetrates the rotor core 11 in the axial direction, and the air passage 81 penetrates the reinforcing rod 73 so as to communicate one end side and the other end side in the axial direction of the rotor 10. Thereby, the above-described Helmholtz resonator can be formed with a simple configuration, and the noise generated via the drive motor 2 can be suppressed.

[0082] Further, in the first embodiment, the first hole portion 71 has a first partition wall 71a that axially partitions the first hole portion 71 so that their volumes are different from each other, and the second hole portion 72 has a second partition wall 72a that axially partitions the second hole portion 72 so that their volumes are different from each other. The reinforcing rod 73 is disposed so as to penetrate through the first partition wall 71a and the second partition wall 72a. The communication holes 85 are formed in respective portions of the reinforcing rod 73 located in the spaces 71b, 71c, 72b, and 72c partitioned by the first partition wall 71a and the second partition wall 72a. Since the first hole portion 71 and the second hole portion 72 are divided into a plurality of spaces 71b, 71c, 72b, and 72c having different volumes, Helmholtz resonators corresponding to a plurality of frequencies can be formed. Thereby, the noise generated via the drive motor 2 can be suppressed.

[0083] (Embodiment 2) Hereinafter, Embodiment 2 will be described in detail with reference to the drawings. In the following description, the same reference numerals are given to the portions common to the first embodiment, and the detailed description thereof will be omitted.

[0084] 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 one-rotor two-stator type motor in which two stators 220 are arranged to face each other in the axial direction with respect to the rotor 210. The rotor 210 and the stator 220 are housed in the housing 290.

[0085] A shaft 230 is inserted through the centers of the rotor 210 and each stator 220. The rotor 210 is fixed to the shaft 230. Each 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 "radial outside", and the side close to the rotational axis J is referred to as the "radial inside". Also, the side of the rotor 210 in the axial direction is referred to as the "axial inside", and the side opposite to the rotor 210 in the axial direction is referred to as the "axial outside".

[0086] 〔Stator〕 As shown in FIG. 6, the stator 220 includes a stator core 221 and a plurality of coils 222. The stator core 221 has an annular back yoke 221a and a plurality (here, nine) of teeth 221b that radially protrude inward in the radial direction from the back yoke 221a. For example, the stator core 221 is a laminated core formed by laminating a plurality of electromagnetic steel sheets with high magnetic permeability in the radial direction.

[0087] The plurality of coils 222 are wound around the plurality of teeth 221b. When the plurality of coils 222 are energized, magnetic flux is generated in the plurality of coils 222. For example, the plurality of coils 222 constitute a three-phase coil group including a U phase, a V phase, and a W phase in which the phases of the flowing currents are different. The coils 222 of each phase are arranged in order in the circumferential direction.

[0088] Similar to the first embodiment, the magnetic flux generated in the plurality of coils 222 includes a rotational magnetic flux for rotating each rotor 210 and a variable magnetic flux (predetermined magnetic flux) for changing the magnetization states of the first magnetic force variable magnet 251 and the second magnetic force variable magnet 252 described later.

[0089] By supplying an alternating current to the plurality of coils 222, a rotating magnetic flux is generated in the plurality of coils 222. Each rotor 210 rotates due to this rotating magnetic flux. Further, during the rotation (or stop) of each rotor 210, a variable magnetic flux is generated in the plurality of coils 222 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 222 for a predetermined time. The magnetization states of the first magnetic force variable magnet 251 and the second magnetic force variable magnet 252, which will be described later, change due to this variable magnetic flux.

[0090] 〔Rotor〕 Next, with reference to FIGS. 7 to 9, the rotor 210 will be described. The rotor 210 includes a rotor core 211, a plurality of magnetic pole portions 212, a plurality of hole portions 271, an outer wall portion 216, an inner wall portion 217, and a plurality of reinforcing rods 273.

[0091] 〔Rotor Core〕 The rotor core 211 is formed in a cylindrical shape. For example, the rotor core 211 is a laminated core in which a plurality of cylindrical electromagnetic steel sheets having a high magnetic permeability are laminated in the radial direction. A shaft hole H230 (see FIG. 9) through which the shaft 230 is inserted is formed at the center of the rotor core 211.

[0092] 〔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 pair of magnetic force fixed magnets 240, a pair of first magnetic force variable magnets 251, and a pair of second magnetic force variable magnets 252. As shown in FIG. 8, the pair of magnetic force fixed magnets 240, the pair of first magnetic force variable magnets 251, and the pair of second magnetic force variable magnets 252 are arranged symmetrically with respect to a specific plane P passing through the center in the axial direction of the rotor 210 and orthogonal to the axial direction.

[0093] The magnetic pole portions 212 adjacent to each other in the circumferential direction of the rotor 210 have different magnetic properties. Specifically, the magnetization directions of the magnetic force fixed magnets 240 are opposite to each other. Also, in the same magnetic pole portion 212, the magnetic force fixed magnets 240 adjacent to each other in the axial direction have opposite magnetization directions.

[0094] <Magnet for magnetic fixation> The magnet 240 for magnetic fixation is embedded in the rotor core 211. The magnet 240 for magnetic fixation extends in a direction orthogonal to the axial direction (tangential direction). Specifically, the magnet 240 for magnetic fixation has a rectangular cross-sectional shape, with its longitudinal direction facing the tangential direction and its short-side direction facing the axial direction. The magnet 240 for magnetic fixation is formed in a sector shape when viewed from the axial direction. The circumferential length of the magnet 240 for magnetic fixation is shorter toward the inner side in the radial direction. Since the material of the magnet 240 for magnetic fixation is the same as that in the aforementioned Embodiment 1, a detailed description thereof is omitted.

[0095] <First magnet with variable magnetic force> The first magnet 251 with variable magnetic force is disposed on one end side in the circumferential direction of the magnet 240 for magnetic fixation. The first magnet 251 with variable magnetic force faces the magnet 240 for magnetic fixation with a gap therebetween in the circumferential direction.

[0096] The first magnet 251 with variable magnetic force is embedded in the rotor core 211. The first magnet 251 with variable magnetic force extends along the axial direction. Specifically, the first magnet 251 with variable magnetic force has a rectangular cross-sectional shape, with its longitudinal direction facing the axial direction and its short-side direction facing the tangential direction.

[0097] The first magnet 251 with variable magnetic force is formed in a sector shape when viewed from the axial direction. The circumferential length of the first magnet 251 with variable magnetic force is shorter toward the inner side in the radial direction. Since the material of the first magnet 251 with variable magnetic force is the same as that in the aforementioned Embodiment 1, a detailed description thereof is omitted.

[0098] <Second magnet with variable magnetic force> The second magnet 252 with variable magnetic force is disposed on the other end side in the circumferential direction of the magnet 240 for magnetic fixation. The second magnet 252 with variable magnetic force faces the magnet 240 for magnetic fixation with a gap therebetween in the circumferential direction.

[0099] The second magnet 252 with variable magnetic force is embedded in the rotor core 211. The second magnet 252 with variable magnetic force extends along the axial direction. Specifically, the second magnet 252 with variable magnetic force has a rectangular cross-sectional shape, with its longitudinal direction facing the axial direction and its short-side direction facing the tangential direction.

[0100] 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 toward the inner side in the radial direction. Since the material of the second magnetically variable magnet 252 is the same as that of the first embodiment described above, a detailed description thereof is omitted.

[0101] 〔Hole portion〕 As shown in FIG. 8, the hole portion 271 is provided across two adjacent magnetic pole portions 212. The hole portion 271 is provided from a portion on one end side in the circumferential direction of one magnetic pole portion 212 to a portion on the other end side in the circumferential direction of the other magnetic pole portion 212. The hole portion 271 is provided on the rotor core 211 on one end side in the axial direction and on the other end side in the axial direction with respect to a specific plane P so as to be symmetric with respect to the specific plane P.

[0102] The hole portion 271 has a T-shaped cross section. The hole portion 271 is disposed inside the magnetic force fixing magnet 240 in the axial direction and also inside the first magnetically variable magnet 251 and the second magnetically variable magnet 252 in the axial direction. The hole portion 271 protrudes outward in the axial direction at the positions of the first magnetically variable magnet 251 and the second magnetically variable magnet 252 in the circumferential direction.

[0103] As shown in FIGS. 7 and 9, the hole portion 271 penetrates the rotor core 211 in the radial direction. The hole portion 271 is formed in a fan shape when viewed from the axial direction. The circumferential length of the hole portion 271 is shorter toward the inner side in the radial direction.

[0104] The hole portion 271 and the magnetic force fixing magnet 240 are separated from each other in the axial and circumferential directions. The hole portion 271 and the first magnetically variable magnet 251 and the second magnetically variable magnet 252 are separated from each other in the axial direction.

[0105] 〔Outer wall portion, inner wall portion〕 The outer wall portion 216 is a wall portion that covers the outer peripheral portion of the rotor core 211. The outer wall portion 216 is arranged along the circumferential surface on the radially outer side of the rotor core 211. The outer wall portion 216 is cylindrical. The outer wall portion 216 is arranged concentrically with the rotor core 211. The inner diameter of the outer wall portion 216 is equal to the outer diameter of the rotor core 211 or slightly larger than the outer diameter of the rotor core 211.

[0106] The inner wall portion 217 is arranged between the rotor core 211 and the shaft 230. 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 the shaft hole H230 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.

[0107] 〔Reinforcing Rod〕 Reinforcing rods 273 are respectively arranged in each of the hole portions 271. Although it will be described in detail later, there are two types of reinforcing rods 273, namely the first reinforcing rod 274 and the second reinforcing rod 275. The number of the first reinforcing rods 274 is the same as the number of the second reinforcing rods 275. In the following description, when these are not distinguished, they are simply referred to as the reinforcing rod 273.

[0108] The reinforcing rod 273 is respectively arranged in the hole portion 271 on one end side in the axial direction from the specific plane P and the hole portion 271 on the other end side in the axial direction from the specific plane P. The reinforcing rod 273 penetrates the rotor core 211 in the radial direction.

[0109] The reinforcing rod 273 includes a head portion 273a, a shaft portion 273b, and a screw portion 273c. The head portion 273a is arranged on one end side of the shaft portion 273b, and the screw portion 273c is formed on the other end side of the shaft portion 273b. The head portion 273a, the shaft portion 273b, and the screw portion 273c are concentric. The head portion 273a has a larger diameter than the shaft portion 273b.

[0110] As shown in FIG. 9, the reinforcing rods 273 are respectively arranged so as to penetrate the hole portion 271 with a gap left between the inner peripheral surface of the hole portion 271. Specifically, the reinforcing rod penetrates the outer wall portion 216, enters the hole portion 271, and extends in the radial direction with a gap left between the inner peripheral surface of the hole portion 271. The threaded portion 273c of the reinforcing rod 273 is connected to the inner wall portion 217 by screwing. On the other hand, the head portion 273a of the reinforcing rod 273 is not penetrated through the outer wall portion 216 but is accommodated in the recess 216a provided in the outer wall portion 216. The depth of the recess 216a is about the same as the thickness of the head portion 273a. Thereby, the reinforcing rod 273 is connected to the outer wall portion 216 and the inner wall portion 217.

[0111] The reinforcing rod 273 is made of a non-magnetic conductor such as aluminum or copper. When magnetic flux for changing the magnetization states of the first magnetically variable magnet 251 and the second magnetically variable magnet 252 is input, the reinforcing rod 273 generates eddy currents that generate repulsive magnetic fluxes that repel the magnetic flux. Due to the repulsive magnetic flux, it becomes difficult for the magnetic flux to enter through the hole portion 271, so that the magnetic flux can be made to flow easily toward the first magnetically variable magnet 251 and the second magnetically variable magnet 252.

[0112] 〔Air passage〕 An air passage through which air passes is formed in the rotor 210. The air passage includes a first air passage 281 formed in the reinforcing rod 273 and a second air passage 282 formed in the shaft 230.

[0113] The first air passage 281 penetrates through the reinforcing rod 273 in a third specific direction that is the axial direction of the reinforcing rod 273. That is, the first air passage 281 penetrates the head portion 273a, the shaft portion 273b, and the threaded portion 273c along the third specific direction. The first air passage 281 communicates one axial end side and the other end side of the rotor 210. The third specific direction is a direction orthogonal to the axial direction of the shaft 230.

[0114] The shaft portion 273b has a plurality (six in FIGS. 4 and 5) of communication holes 285 that communicate the first air passage 281 with the hole portion 271. The communication holes 285 are arranged side by side in the first specific direction and are arranged to face each other in a second specific direction orthogonal to the first specific direction.

[0115] The first reinforcing rod 274 and the second reinforcing rod 275 have different diameters of the communication holes 285. As shown in FIG. 9, the diameter of the communication hole 285 of the first reinforcing rod 274 is larger than the diameter of the communication hole 285 of the second reinforcing rod 275.

[0116] The second air passage 282 extends in the axial direction of the shaft 230. The flow cross-sectional area of the second air passage 282 is larger than the flow cross-sectional area of the first air passage 281. In the axial direction, the second air passage 282 does not pass through the entire rotor 210 and is blocked midway.

[0117] The inner wall portion 217 has an inflow hole 284 at the position of the first air passage 281 to communicate the first air passage 281 with the second air passage 282. Thereby, the second air passage 282 and the outside of the rotor 210 are communicated by the first air passage 281.

[0118] Air flows from the second air passage 282 into the first air passage 281 through the inflow hole 284. A part of the air flowing into the first air passage 281 passes through the communication hole 285 and escapes to the hole portion 271. The remaining air flowing into the first air passage 281 flows out to the outside of the rotor 210.

[0119] Also in the rotor 210 according to the second embodiment, a Helmholtz resonator is constituted by the first air passage 281, the communication hole 285, and the hole portion 271. With the Helmholtz resonator, among the vibrations input to the drive motor 202, vibrations having a frequency corresponding to the resonance frequency of the Helmholtz resonator can be absorbed. Thereby, the noise generated via the drive motor 202 can be suppressed.

[0120] 〔Effects of the Second Embodiment〕 As described above, in Embodiment 2, the shaft 230 has a second air passage 282 extending axially within the shaft 230, the reinforcing rod 273 penetrates the rotor core 211 in the radial direction, and the first air passage 281 penetrates the reinforcing rod 273 so as to communicate the second air passage 282 with the outside of the rotor 210. By forming the second air passage 282 in the shaft 230 and communicating it with the first air passage 281, vibration is easily transmitted to the reinforcing rod 273, and the sound absorption efficiency can be improved. Thereby, the noise generated via the drive motor 202 can be suppressed.

[0121] In Embodiment 2, there are two types of reinforcing rods 273, namely a first reinforcing rod 274 and a second reinforcing rod 275, and the diameter of the communication hole 285 formed in the first reinforcing rod 274 is different from the diameter of the communication hole 285 formed in the second reinforcing rod 275. By having different diameters of the communication holes 285, Helmholtz resonators corresponding to a plurality of frequencies can be formed. Thereby, the noise generated via the drive motor 202 can be suppressed.

[0122] [Modification Example 1 of Embodiment 2] FIG. 10 shows Modification Example 1 of the present Embodiment 2. In Modification Example 1, there is only one type of reinforcing rod 373. The diameters of the communication holes 385 provided in each reinforcing rod 373 are the same.

[0123] In Modification Example 1, a partition wall 371a that divides the hole portion 371 into two spaces is formed in the hole portion 371. The volumes of the spaces partitioned by the partition wall 371a are different from each other. Specifically, the partition wall 371a divides the hole portion 371 into a relatively large space 371b with a relatively large volume and a relatively small space 371c with a relatively small volume. Note that a plurality of partition walls 371a may be provided in the hole portion 371. In this case, the plurality of partition walls 371a partition the hole portion 371 so that the volumes of the plurality of spaces formed by the partitioning are different from each other.

[0124] In Modification 1, the reinforcing rod 373 penetrates the outer wall portion 316 and enters the first hole portion 371. The reinforcing rod 373 penetrates the partition wall 371a, passes through the inside of the hole portion 371, and then penetrates the inner wall portion 317. The threaded portion 373c of the reinforcing rod 373 is connected to the inner wall portion 317 by screwing.

[0125] The communication holes 385 are formed in respective portions of the reinforcing rod 373 that are located in the large space 371b and the small space 371c. The communication holes 385 are not formed in the portion of the reinforcing rod 373 that is located at the partition wall 371a.

[0126] In the modification, since the hole portion 371 is divided into a plurality of spaces 371b and 371c having different volumes, Helmholtz resonators corresponding to a plurality of frequencies can be formed for the sound passing through each reinforcing rod 373. As a result, it is possible to cancel sounds of a plurality of frequencies with respect to the sound passing through each reinforcing rod 373, and it is possible to suppress the noise generated via the drive motor 202.

[0127] (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.

[0128] In Embodiments 1 and 2, the automobile 1 was a hybrid vehicle having an engine 3. However, the automobile 1 is not limited thereto, and may be an electric vehicle having only the drive motors 2 and 202 as drive sources.

[0129] In Embodiment 1, the first partition wall 71a and the second partition wall 72a were arranged at positions shifted to one side in the axial direction with respect to the center in the axial direction in the first hole portion 71 and the second hole portion 72. However, the first partition wall 71a and the second partition wall 72a are not limited thereto, and may be arranged at the center in the axial direction in the first hole portion 71 and the second hole portion 72. In this case, for example, a non-magnetic member may be arranged only in one of the partitioned spaces so as to make the volume into which air enters different.

[0130] In Embodiment 2, the hole portion 271 was provided separately on one axial end side from the specific plane P and on the other axial end side from the specific plane P. However, it is not limited to this, and it may be integrated like the hole portion 471 shown in FIG. 11. In this case, the cross section of the hole portion 471 is in a cross shape. Further, since the number of the hole portions 471 decreases, the number of the reinforcing rods 473 arranged in the hole portion 471 also decreases. The reinforcing rod 473 is arranged at the intersection portion in the hole portion 471.

[0131] In Embodiment 2, the reinforcing rod 273 was of two types, the first reinforcing rod 274 and the second reinforcing rod 275, but the number of types of the reinforcing rod 273 may be three or more. The diameters of the communication holes 285 of the various types of reinforcing rods 273 are different from each other.

[0132] The foregoing embodiments are merely illustrative and should not be construed as limiting the scope of the present disclosure. 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

[0133] The technology disclosed herein is useful as a rotor structure of a rotating electrical machine.

Explanation of Signs

[0134] 10 Rotor 11 Rotor Core 14 First End Plate 15 Second End Plate 20 Stator 21 Stator Core 40 Magnetically Fixed Magnet 51 First Magnetically Variable Magnet 52 Second Magnetically Variable Magnet 71 First Hole Portion 71a First Partition Wall 71b Large Space 71c Small Space 72 Second Hole Portion 72a Second Partition Wall 72b Large space 72c Small space 73 Reinforcing rod 81 Air passage 85 Communication hole 210 Rotor 211 Rotor core 212 Pole part 216 Outer wall part 217 Inner wall part 220 Stator 240 Magnet for magnetic fixation 251 First magnet with variable magnetic force 252 Second magnet with variable magnetic force 271 Hole part 273 Reinforcing rod 274 First reinforcing rod 275 Second reinforcing rod 281 First air passage 282 Second air passage 285 Communication path 373 Reinforcing rod 371 Hole part 371a Partition wall 371b Large space 371c Small space 381 First air passage 385 Communication path 471 Hole part 475 Reinforcing rod

Claims

1. A rotor structure of a rotating electrical machine, comprising a rotor having a rotor core and fixed to a shaft, and a stator having a stator core disposed with a gap from the rotor core, the rotor core includes a plurality of rods penetrating in the axial direction or the radial direction and arranged side by side in the circumferential direction, the rotor core has a plurality of hole portions provided at intervals in the circumferential direction, the rods are respectively arranged so as to penetrate the hole portions with a gap between the rods and the inner peripheral surface of the hole portions, furthermore, the rod, a first air passage penetrating in the axial direction of the rod and through which air passes, a plurality of communication holes communicating the first air passage with the hole portions, characterized in that it has. A rotor structure of a rotating electrical machine.

2. In the rotor structure of the rotating electrical machine according to Claim 1, 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, the rod penetrates the rotor core in the axial direction, the first air passage penetrates the rod so as to communicate one end side and the other end side in the axial direction of the rotor. A rotor structure of a rotating electrical machine.

3. In the rotor structure of the rotating electrical machine according to Claim 2, the hole portion has a partition wall partitioning the hole portion in the axial direction, the rod is arranged to penetrate the partition wall, the communication holes are formed in respective portions of the rod located in each space partitioned by the partition wall, each space partitioned by the partition wall has a different volume from each other. A rotor structure of a rotating electrical machine.

4. In the rotor structure of the rotating electrical machine according to Claim 1, 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, the shaft has a second air passage extending in the axial direction inside the shaft, the rod penetrates the rotor core in the radial direction, the first air passage penetrates the rod so as to communicate the second air passage with the outside of the rotor. A rotor structure of a rotating electrical machine.

5. In the rotor structure of the rotating electrical machine according to Claim 4, there are a plurality of types of the rods, the diameter of the communication holes formed in one type of the rods is different from the diameter of the communication holes formed in the other type of the rods. A rotor structure of a rotating electrical machine.

6. In the rotor structure of the rotating electrical machine according to claim 4, the hole portion has a partition wall that partitions the hole portion in the radial direction, the rod is disposed so as to penetrate the partition wall, the communication holes are formed in respective portions of the rod located in respective spaces partitioned by the partition wall, each space partitioned by the partition wall has a different volume from each other, and a rotor structure of a rotating electrical machine is characterized thereby.

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