JP2014220884A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine which can be rotated at high speed and is capable of outputting high torque in a low-speed rotation range.SOLUTION: An electric motor 1 comprises an outer stator 3 and an inner stator 4 which are supported by a rotary shaft 21 in a relatively rotatable manner and disposed between the electric motor 1 and an output rotor 5 with an interval interposed therebetween outside and inside of a radial direction. By separately electrifying an outer coil 15 and an inner coil 18 provided in the outer stator 3 and the inner stator 4, respectively, a rotor magnetic flux passing between the outer and inner stators 3 and 4 and the output rotor 5 is adjusted through stronger field control which increases the rotor magnetic flux closer to the inner stator 4 and weaker field control which decreases the rotor magnetic flux closer to the outer stator 3.

Description

  The present invention relates to a rotating electrical machine.

  2. Description of the Related Art Conventionally, some rotating electrical machines include a so-called embedded magnet type rotor in which a permanent magnet is embedded in a rotor core (see, for example, Patent Document 1). In a rotating electrical machine (IPM motor) having such an embedded magnet type rotor, not only magnet torque by a permanent magnet but also reluctance torque is generated. Therefore, a so-called surface magnet type rotor having a permanent magnet fixed on the surface of a rotor core. There is an advantage that a high torque can be obtained as compared with the one provided with.

JP 2010-233346 A

  By the way, in a rotating electrical machine in which a rotor is provided with a permanent magnet as described above, since the magnetic flux produced by the permanent magnet is substantially constant, an induced voltage (reversely generated) generated in the stator coil under a constant power supply voltage condition. (Electromotive force) increases in proportion to the rotational speed of the rotor. When this induced voltage reaches the upper limit of the power supply voltage, the rotor can no longer be rotated at a high speed. Therefore, in applications that require high-speed rotation, it is conceivable to design the amount of magnetic flux created by permanent magnets so that the rotor can rotate at a sufficiently high speed. Therefore, it is impossible to obtain a sufficiently high torque.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a rotating electrical machine that can rotate at a high speed and can output a high torque in a low-speed rotation region.

  In order to solve the above-mentioned problem, the rotating electrical machine according to claim 1 is provided with a radial gap between a bottomed cylindrical rotor fixed coaxially to a rotating shaft and an outer peripheral surface of the rotor. A plurality of first teeth portions of the annular first stator core that are arranged to face each other extend radially inward, and a first coil is wound around each first tooth portion and fixed in the housing. And a plurality of second teeth portions of the annular second stator core extend radially outward, and are arranged opposite to each other between the inner peripheral surface of the rotor and the inner peripheral surface of the rotor. A second stator wound around the portion and fixed in the housing, and the first coil and the second coil are energized in the same phase, or shifted in phase. The gist is that it is energized.

  According to the above configuration, the rotary electric machine has a double stator structure in which the first stator is disposed between the outer peripheral surface of the rotor and the second stator is disposed between the inner peripheral surface and the second stator. Three-phase currents can be separately supplied to the first coil and the second coil provided in each stator in terms of energization current and phase. As a result, when both stators are energized in the same phase, the torque generated by the respective rotor magnetic fluxes passing between the first stator, the second stator, and the rotor is added, so that a high torque is applied to the rotor. Can be generated.

  According to a second aspect of the present invention, in the rotating electrical machine according to the first aspect, the first stator has a larger torque constant than the second stator, and the rotor is rotated by magnetic poles formed on the first stator. The gist of adjusting the magnetic flux passing between the first stator and the rotor by energizing the second stator and increasing or decreasing the number of flux linkages with the first stator among the rotor magnetic flux. To do.

  According to the above configuration, the magnetic flux passing between the first stator and the rotor is adjusted by rotating the rotor with the magnetic poles of the first stator having a large torque constant and energizing the second stator to change the current and phase. The number of flux linkages between the rotor and the first stator can be increased or decreased. As a result, when the second stator is subjected to strong field control and the first stator is subjected to normal control or weak field control, the rotor magnetic flux passing between the second stator and the rotor increases, and the first stator and the rotor Since the rotor magnetic flux passing between the first and second stators decreases, an increase in the induced voltage generated in the first stator can be suppressed and the rotor can be rotated at a high speed.

  According to a third aspect of the present invention, in the rotating electric machine according to the first or second aspect, the rotor includes a rotor core fixed to the rotating shaft so as to be integrally rotatable, and a space is provided in the rotor core in a circumferential direction. A plurality of permanent magnets that are radially arranged, embedded and fixed so that the longitudinal direction of the cross-sectional shape is parallel to the radial direction, and magnetized so that the polarities of different magnetic poles are alternately arranged in the circumferential direction; It is a summary to provide.

  According to the above configuration, the rotor of the rotating electrical machine includes a plurality of permanent magnets embedded in the circumferential direction in which the longitudinal direction of the cross section is radially spaced from the radial direction in the rotor core. An embedded magnet rotor is configured in which the polarities of magnetic poles sandwiched between permanent magnets arranged so that one polarity is adjacent to the other polarity are alternately arranged in the circumferential direction. This makes it possible to increase the output torque and generate a high torque.

    ADVANTAGE OF THE INVENTION According to this invention, the rotary electric machine which can be rotated at high speed and can output a high torque in a low-speed rotation area can be provided.

The longitudinal cross-sectional view along the axial direction of the rotary electric machine which concerns on one Embodiment of this invention. Sectional drawing orthogonal to the axial direction of the rotary electric machine seen from the AA direction in FIG. The schematic diagram which shows the flow of the rotor magnetic flux in the case of generating a high torque in the low speed rotation area which concerns on embodiment of this invention. The schematic diagram which shows the flow of the rotor magnetic flux in the case of making it rotate at high speed based on embodiment of this invention.

Hereinafter, a rotating electrical machine according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view along the axial direction of a rotating electrical machine according to an embodiment of the present invention, and FIG. 2 is a sectional view orthogonal to the axial direction of the rotating electrical machine viewed from the AA direction in FIG. .

  A rotary electric machine (hereinafter referred to as an electric motor) 1 shown in FIGS. 1 and 2 is a three-phase brushless motor used as a drive source of an electric vehicle or a hybrid vehicle, for example. As shown in FIG. 1, the electric motor 1 includes a cylindrical housing 2, an outer stator 3 as a first stator housed in the housing 2, and a radially inner side (inner peripheral side) of the outer stator 3. Output rotor 5 as a cylindrical rotor arranged with a gap between them, and an inner stator as a second stator housed in the housing 2 and arranged at a radial inner side (inner peripheral side) of the output rotor 5 4 is provided.

  The housing 2 has a bottomed cylindrical housing body 6 that is open at one end (right side in FIG. 1), and a disc-shaped cover 7 that is provided so as to close the opening end of the housing body 6. ing. An insertion hole 8 penetrating in the axial direction is formed in the center of the bottom 6a of the housing body 6.

  The outer stator 3 has a cylindrical cylindrical portion 12 fixed to the inner side of the cylindrical portion 6b of the housing main body 6, and a plurality (12 in the present embodiment) extending radially inward from the cylindrical portion 12 in the radial direction. The outer stator core 14 made of the teeth 13 is provided. The outer stator core 14 is configured by laminating a plurality of electromagnetic steel plates such as silicon steel plates. A plurality of (in this embodiment, 12) outer coils 15 are wound around each tooth 13. The connecting end of the outer coil 15 is pulled out of the housing 2 and connected to a control device (not shown).

  The output rotor 5 includes a cylindrical rotor core 22 fixed so as to rotate integrally with the rotary shaft 21 and a plurality (eight in this embodiment) of permanent magnets 23 embedded and fixed in the rotor core 22. Yes. That is, the output rotor 5 of the present embodiment is configured as a so-called embedded magnet type rotor.

  Specifically, the rotating shaft 21 is formed in a columnar shape, and is rotatably supported via a bearing 24 provided in the insertion hole 8 of the bottom portion 6a. The rotor core 22 includes a core body 25 in which the permanent magnets 23 are embedded, a first connecting member 26 that is fixed to one end side (right side in FIG. 1) of the core body 25 and is connected to the rotary shaft 21 so as to be integrally rotatable. A cylindrical second connecting member 27 is fixed to the other end side (left side in FIG. 1) of the core body 25 and connected to the rotary shaft 21 so as to be integrally rotatable. The core body 25 is formed by laminating a plurality of electromagnetic steel plates, and the first and second connecting members 26 and 27 are made of a nonmagnetic material such as stainless steel.

  The core body 25 is formed in a relatively thick cylindrical shape, and a plurality of cavities (slots) 30 in which the permanent magnets 23 are disposed are formed in the core body 25 at equal angular intervals in the circumferential direction. Has been. The slots 30 are each formed in a hole shape having a rectangular cross section extending in the axial direction. The slots 30 are provided radially such that the longitudinal direction of the rectangle formed by the cross section is parallel to the radial direction while being spaced apart in the circumferential direction.

  A support shaft 20 is formed on the inner surface of the cover 7 so as to protrude from the center toward the bottom 6a side (left side in FIG. 1) of the housing body 6. The support shaft 20 is formed in a stepped rod shape whose outer diameter decreases stepwise as it goes toward the bottom 6a. The first connecting member 26 constituting the output rotor 5 is formed in a cylindrical shape and is rotatably supported via a bearing 29 provided on the support shaft 20. The second connecting member 27 is formed in an annular shape, and a fitting hole 28 formed in the center of the second connecting member 27 is press-fitted into the outer periphery of the rotating shaft 21, so that the second connecting member 27 is integrated with the rotating shaft 21. It is connected rotatably.

  The electric motor 1 includes an inner stator 4 that is disposed on the inner peripheral side of the output rotor 5 at a radial interval and is fixed to the outer periphery of the support shaft 20. The inner stator 4 includes a cylindrical cylindrical portion 19 and an inner stator core 17 having a plurality of teeth 16 extending radially outward from the cylindrical portion 19, and an inner coil 18 wound around each tooth 16 of the inner stator core 17. It has. The inner stator core 17 is configured by laminating a plurality of electromagnetic steel plates such as silicon steel plates. The inner stator 4 of the present embodiment is provided with the same number of inner coils 18 as the outer coils 15 of the outer stator 3 (12 in this embodiment). Further, the connecting end portion of the inner coil 18 is pulled out of the housing 2 and connected to a control device (not shown).

  As the permanent magnet 23, a segment magnet formed in a rectangular plate shape extending in the axial direction is employed. The cross-sectional shape orthogonal to the axial direction of the permanent magnet 23 is a rectangular shape corresponding to the cross-sectional shape of the slot 30, and the permanent magnet 23 is inserted into the slot 30 so that the core body 25 (rotor core 22) is inserted. It is fixed. In the circumferential direction, the permanent magnet 23 is permanent with one polarity (for example, CCW is N pole and CW is S pole), and the other is permanent (for example, CCW is S pole and CW is N pole). Magnetization (magnetization) is performed so that the polarities of the rotor magnetic pole portions 31 sandwiched between the permanent magnets 23 in the rotor core 22 are arranged alternately in the circumferential direction so as to be adjacent to the magnets 23.

  The permanent magnet 23 is magnetized in a direction substantially along each plate thickness direction, and the core body 25 is a magnetic path of the magnetic flux of the permanent magnet 23 that passes through the outer peripheral edge and the inner peripheral edge of the rotor core 22. Note that a sintered magnet (for example, a neodymium-based sintered magnet) is used for the permanent magnet 23 of the present embodiment, and the permanent magnet 23 is magnetized after being disposed and fixed in the slot 30. Alternatively, the first magnetized one may be disposed and fixed in the slot 30.

  As described above, the electric motor 1 is configured as a radial gap motor having a double stator structure in which the outer stator 3 and the inner stator 4 are disposed on the outer peripheral portion and the inner peripheral portion of the output rotor 5. The current is separately supplied to the outer coil 15 and the inner coil 18 with respect to the energization amount (energization current) and the phase. The torque constants (induced voltage constants) of the outer stator 3 and the inner stator 4 are different, the torque constant of the outer stator 3 is set large, and the torque constant of the inner stator 4 is set small.

  A rotating magnetic field generated when drive power is supplied from the control device to the coils 15 and 18 of the outer stator 3 and the inner stator 4, a rotor magnetic flux passing between the outer stator 3 and the output rotor 5, and an inner stator 4, based on the relationship between the rotor magnetic flux passing between the rotor 4 and the output rotor 5, that is, the magnetic attractive force generated between the rotating magnetic field by the outer stator 3 and the inner stator 4 and the magnetic flux of the permanent magnet 23, The output rotor 5 is rotated by the repulsive force.

Next, the operation of the electric motor 1 according to this embodiment of the present invention configured as described above will be described.
FIG. 3 is a schematic diagram showing the flow of the rotor magnetic flux when high torque is generated in the low speed rotation region according to the embodiment of the present invention. FIG. 4 is a diagram of the rotor magnetic flux when rotating at high speed according to the embodiment of the present invention. It is a schematic diagram which shows a flow.

  In the electric motor 1 of the present embodiment, as shown in FIG. 3, the same phase is applied to the outer coil 15 (see FIG. 2) provided in the outer stator 3 and the inner coil 18 (see FIG. 2) provided in the inner stator 4. When the current is supplied (normal control), the number of magnetic fluxes of the output rotor 5 interlinked with the outer stator 3 and the inner stator 4 is constant, so that torque generated in the output rotor 5 is applied to the outer stator 3 and the inner stator 4. The torques generated between the generated rotating magnetic field pole and the magnetic pole of the permanent magnet 23 of the output rotor 5 are added together. Thereby, it is possible to generate a high torque in the output rotor 5. Here, since the torque constant of the outer stator 3 is larger than the torque constant of the inner stator 4, the outer stator 3 mainly functions as a stator that generates torque. A part of the magnetic flux path and amount passing between the outer stator 3 and the inner stator 4 and the output rotor 5 are indicated by solid arrows.

  On the other hand, as shown in FIG. 4, field control of the inner stator 4 is strengthened (that is, a magnetic flux in the same direction as the permanent magnet 23 is generated by passing a current through the inner coil 18 of the inner stator 4), and the outer stator 3 is When normal control or field weakening control (generating a magnetic flux in the direction opposite to that of the permanent magnet 23) is performed, the rotor magnetic flux linked with the strong field controlled inner stator 4 side increases and the other outer stator 3 side is linked. The rotor magnetic flux to be absorbed is absorbed by the inner stator 4 side and decreases. As a result, by changing the energization current and phase to the stator, the number of flux linkages on the outer stator 3 side that mainly generates torque is reduced, so that an increase in induced voltage generated on the outer stator 3 side is suppressed. The output rotor 5 can be rotated at high speed. At this time, since the torque constant of the inner stator 4 is small, the inner stator 4 is unlikely to reach voltage saturation due to the increase of the induced voltage even if the strong field control is performed. A part of the magnetic flux path and amount passing between the outer stator 3 and the inner stator 4 and the output rotor 5 are indicated by solid arrows.

  Further, even if the outer stator 3 is weakened and field-controlled without energizing the inner stator 4 side, the same rotor magnetic flux flow as in FIG. 4 can be obtained. At this time, the rotor magnetic flux leaks to the inner stator 4 side, and the number of interlinkage magnetic fluxes with the outer stator 3 side decreases, so that the induced voltage generated on the outer stator 3 side is suppressed and the output rotor 5 is rotated at high speed. Is possible.

  Next, the effect of the electric motor 1 according to this embodiment of the present invention configured as described above will be described.

  (1) The outer stator 3 and the inner stator 4 are provided between the outer peripheral surface and the inner peripheral surface of the output rotor 5 so as to be spaced from each other in the radial direction, and both stators, that is, the outer stator 3 and the inner stator are provided. When current is supplied to 4 so that currents of the same phase flow, torque generated by the two outer stators 3 and the inner stator 4 is added to increase the torque. As a result, the output rotor 5 can output high torque in the low speed rotation region.

  (2) By performing strong field control on the outer stator 3 side and normal control or weak field control on the inner stator 4 side, the number of interlinkage magnetic fluxes with the inner stator 4 is increased, and the rotor magnetic flux is transferred to the inner stator 4 side. Absorbed and the number of flux linkages with respect to the outer stator 3 decreases. Thereby, the output rotor 5 can be rotated at high speed. In addition, the rotor magnetic flux leaks to the inner stator 4 side and the number of interlinkage magnetic fluxes with respect to the outer stator 3 is also reduced by performing field weakening control on the outer stator 3 side without energizing the inner stator 4 side. Thereby, the output rotor 5 can be rotated at high speed.

  (3) Since the two stators of the outer stator 3 and the inner stator 4 are provided, even if one of the systems fails, the operation of the vehicle can be continued in the other system. As a result, the vehicle can be safely moved and retracted.

  As mentioned above, although embodiment which concerns on this invention was described, this invention can also be implemented with another form.

  In the above embodiment, a brushless motor is used as the electric motor 1, but the present invention is not limited thereto, and for example, an induction motor or a reluctance motor may be used.

  In the above embodiment, the permanent magnets 23 are spaced radially in the circumferential direction and radially provided so that the longitudinal direction of the rectangular cross section is parallel to the radial direction. It may be arranged such that the longitudinal direction of the rectangle formed by the cross section is inclined with respect to the radial direction while being spaced apart, and the arrangement can be changed as appropriate. Further, the permanent magnet 23 may be formed in a plate shape curved in an arc shape, and the shape can be appropriately changed.

  In the above embodiment, the number of inner coils 18 equal to the number of outer coils 15 of the outer stator 3 is provided in the inner stator 4, but the number may be different and can be changed as appropriate.

  In the above-described embodiment, the electric motor 1 is configured as an inner rotor type radial gap motor, but is not limited thereto, and may be configured as an outer rotor type radial gap motor. In this case, the first rotor is arranged radially inside the output rotor 5, and the second rotor is arranged radially outside the output rotor 5.

  In the above embodiment, the present invention is embodied in a rotating electrical machine (electric motor 1) used as a drive source for an electric vehicle or a hybrid vehicle. However, the present invention is not limited to this, and other devices such as an electric power steering device, for example. It may be used as a drive source for the power supply or as a generator.

1: electric motor (rotary electric machine), 2: housing, 3: outer stator (first stator), 4: inner stator (second stator), 5: output rotor, 6: housing body,
6a: bottom part, 7: cover, 8: insertion hole, 12: cylindrical part,
13: Outer teeth (first teeth portion), 14: Outer stator core,
15: outer coil (first coil), 16: inner teeth (second teeth portion),
17: inner stator core, 18: inner coil (second coil), 19: cylindrical portion,
20: support shaft, 21: rotating shaft, 22: rotor core, 23: permanent magnet, 24: bearing,
25: Core body, 26: First connecting member, 27: Second connecting member, 28: Fitting hole, 29: Bearing, 30: Slot, 31: Rotor magnetic pole part

Claims (3)

A bottomed cylindrical rotor fixed coaxially to the rotating shaft;
A plurality of first teeth portions of the annular first stator core extend radially inward and are opposed to each other with a space in the radial direction between the outer peripheral surface of the rotor and the first teeth portions are A first stator wound with one coil and fixed in the housing;
A plurality of second teeth portions of the annular second stator core extend radially outward from the inner peripheral surface of the rotor and spaced apart from each other in the radial direction. A second stator wound around the second coil and fixed in the housing,
The rotating electrical machine characterized in that the first coil and the second coil are energized with the same phase, or are energized with a phase shift. In the rotating electrical machine according to claim 1,
The first stator has a larger torque constant than the second stator,
The rotor is rotated by the first stator and the magnetic flux passing between the first stator and the rotor is adjusted by energizing the second stator, and the chain between the rotor stator magnetic flux and the first stator is adjusted. A rotating electrical machine characterized by increasing or decreasing the number of magnetic flux exchanges. In the rotating electrical machine according to claim 1 or 2,
The rotor is a rotor core fixed to the rotating shaft so as to be integrally rotatable;
The rotor core is radially arranged, embedded and fixed so that the longitudinal direction of the cross-sectional shape is parallel to the radial direction, and the polarities of different magnetic poles are alternately arranged in the circumferential direction. A rotating electric machine comprising: a plurality of permanent magnets magnetized in this manner.

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