JP4890056B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor.

Conventionally, for example, first and second rotors provided concentrically around a rotating shaft of an electric motor are provided, and the first and second rotors are provided in accordance with the rotational speed of the electric motor or the rotational magnetic field generated in the stator. An electric motor that controls the relative position of the second rotor in the circumferential direction, that is, the phase difference is known (see, for example, Patent Document 1).
In this electric motor, for example, when the phase difference between the first and second rotors is controlled according to the rotational speed of the electric motor, the first and second elements are displaced via a member that is displaced along the radial direction by the action of centrifugal force. The relative position in the circumferential direction of the rotor is changed. For example, when the phase difference between the first and second rotors is controlled in accordance with the speed of the rotating magnetic field generated in the stator, the stator windings are kept in a state where each rotor maintains the rotation speed due to inertia. The relative position in the circumferential direction of the first and second rotors is changed by passing a control current and changing the rotating magnetic field velocity.
JP 2002-204541 A

By the way, in the electric motor according to the above prior art, for example, when controlling the phase difference between the first and second rotors according to the rotational speed of the electric motor, the centrifugal force according to the operating state of the electric motor, that is, the rotational speed is There is a problem in that the phase difference between the first and second rotors can be controlled only in the operating state, and the phase difference cannot be controlled at an appropriate timing including the stop state of the electric motor. In addition, when the electric motor is mounted on a vehicle as a drive source, etc., when the external vibration is likely to act on the electric motor, the phase difference between the first and second rotors is determined only by the centrifugal force. The problem is that it is difficult to control properly. In addition, in this case, since the phase difference is controlled regardless of the fluctuation of the power supply voltage at the power supply to the motor, for example, the magnitude relationship between the power supply voltage and the counter electromotive voltage of the motor is reversed. May occur.
For example, when the phase difference between the first and second rotors is controlled according to the speed of the rotating magnetic field generated in the stator, the rotating magnetic field speed is changed, which complicates the motor control process. Problem arises.
Further, when changing the induced voltage constant of the electric motor by controlling the phase difference between the first and second rotors, the permanent magnet provided in the first rotor and the permanent magnet provided in the second rotor It is desired to diversify the contents of field control by appropriately increasing the variable width of the induced voltage constant according to the relative distance between the two.

  The present invention has been made in view of the above circumstances, and by making the induced voltage constant variable easily and appropriately while suppressing the complexity of the electric motor, the operable rotation speed range and torque range are expanded. An object of the present invention is to provide an electric motor capable of improving the operation efficiency and expanding the operable range with high efficiency.

In order to solve the above-described problems and achieve the object, an electric motor according to a first aspect of the present invention includes an inner peripheral side permanent magnet (for example, an inner peripheral side permanent magnet in the embodiment) arranged along the circumferential direction. An inner circumferential rotor (for example, inner circumferential rotor 11 in the embodiment) having a magnet 11a) and an outer peripheral permanent magnet (for example, outer circumferential permanent in the embodiment) arranged along the circumferential direction. The rotating shafts of the outer circumferential rotor (for example, the outer circumferential rotor 12 in the embodiment) having the magnet 12a) are arranged coaxially, and at least any of the inner circumferential rotor and the outer circumferential rotor Rotating means that can change the relative phase between the inner circumferential rotor and the outer circumferential rotor by rotating one of them around the rotation axis (for example, phase control in the embodiment) Device 15), wherein the outer peripheral rotor , The peripheral wall portion to which the outer peripheral side permanent magnet is fixed (for example, the peripheral wall pieces 31b,..., 31b in the embodiment) and the bottom portion made of a magnetic material connected to the peripheral wall portion (for example, in the embodiment) The bottom portion 31a) is formed in a substantially bottomed cylindrical shape, and passes through the peripheral wall portion and the bottom portion from a position where the outer peripheral side permanent magnet is fixed on the peripheral wall portion (for example, the outer peripheral surface 31B in the embodiment). and includes a magnetic flux short-circuit suppressing portion at a predetermined position of the bottom portion on a virtual path towards said rotary shaft (e.g., the magnetic flux short-circuit suppressing portion 35 in the embodiment), the predetermined position is along the axial direction a position overlapping in the axial end surface of the inner peripheral permanent magnets when viewed Te, the magnetic flux short circuit suppression unit, have a small magnetic permeability as compared with the portion other than the magnetic flux short circuit suppressing portion of said bottom Rukoto It is characterized by.

According to the electric motor having the above configuration, with respect to the bottom portion and the peripheral wall portion formed in a substantially bottomed cylindrical shape, a virtual heading from the position where the outer peripheral side permanent magnet is fixed on the peripheral wall portion to the rotation axis via the peripheral wall portion and the bottom portion. By providing a magnetic flux short-circuit suppressing portion having a relatively small magnetic permeability at a predetermined position on the bottom portion on a typical path, a magnetic path is formed between the outer peripheral side permanent magnet and the inner peripheral side permanent magnet along the virtual path. It is possible to prevent a short circuit from occurring. In addition, for example, a desired rigidity is ensured as compared with a case where a shaft member for transmitting the driving force of the outer rotor to the outside is press-fitted into the inner peripheral portion of the annular rotor core including the outer permanent magnet. On the other hand, it is possible to prevent the thickness of the bottom portion and the peripheral wall portion, in particular, the radial thickness of the outer peripheral rotor from increasing.
This suppresses an increase in the distance between the outer peripheral side permanent magnet fixed to the peripheral wall portion and the inner peripheral side permanent magnet of the inner peripheral side rotor, and appropriately sets the variable width of the induced voltage constant. Can be increased.

And, for example, in the field strengthening state by the field magnetic flux of the inner peripheral side permanent magnet with respect to the field magnetic flux of the outer peripheral side permanent magnet, the torque constant (that is, torque / phase current) of the motor is set to a relatively high value. The maximum torque value output by the motor can be reduced without reducing the current loss during motor operation or without changing the maximum output current of the inverter that controls the energization of the stator windings. The maximum value of the operating efficiency of the electric motor can be increased, and the high efficiency region where the operating efficiency is equal to or higher than the predetermined efficiency can be expanded.
In addition, the state change between the field strengthening state and the field weakening state can be set continuously, and the induced voltage constant of the motor can be continuously changed to an appropriate value. As a result, it is possible to continuously change the values of the rotational speed and torque at which the electric motor can be operated, and it is possible to expand the range of the rotational speed and torque at which the electric motor can be operated.

  Furthermore, in the electric motor according to the second aspect of the present invention, the relative phase between the inner rotor and the outer rotor is changed by the rotating means in the magnetic flux short-circuit suppressing unit. Thus, the circumferential position of the inner peripheral permanent magnet when viewed along the direction parallel to the rotation axis and the circumferential position of the magnetic flux short-circuit suppressing portion can be overlapped with each other. It is characterized by being.

  According to the electric motor having the above configuration, in the state where the circumferential position of the inner peripheral side permanent magnet viewed along the direction parallel to the rotation axis (axial direction) and the circumferential position of the magnetic flux short-circuit suppression unit overlap, the peripheral wall portion A short circuit occurs between the outer permanent magnet and the inner permanent magnet along a virtual path from the position where the outer permanent magnet is fixed to the rotation axis from the position where the outer permanent magnet is fixed. Can be prevented appropriately.

  Furthermore, in the electric motor according to a third aspect of the present invention, the magnetic flux short-circuit suppressing portion is a through-hole penetrating the bottom portion in the thickness direction.

  According to the electric motor having the above-described configuration, the outer peripheral side permanent magnet and the inner peripheral side permanent magnet are formed by using the through hole provided in the bottom portion as a magnetic flux short-circuit suppressing unit, due to a space having a relatively small permeability in the through hole. It can prevent appropriately that a magnetic circuit short circuit arises between.

  Furthermore, in the electric motor according to the fourth aspect of the present invention, the magnetic flux short circuit suppressing portion is a concave portion provided on the surface of the bottom portion.

  According to the electric motor having the above configuration, the concave portion provided at the bottom portion is used as a magnetic flux short-circuit suppressing portion, so that the space between the outer peripheral side permanent magnet and the inner peripheral side permanent magnet is relatively small in the concave portion. It can prevent appropriately that a magnetic circuit short circuit arises in between.

  Furthermore, an electric motor according to a fifth aspect of the present invention is characterized by including a member made of a non-magnetic material attached to the recess.

  According to the electric motor having the above configuration, the concave portion provided in the bottom portion is used as the magnetic flux short-circuit suppressing portion, so that the non-magnetic material having a relatively small permeability mounted in the concave portion and the outer peripheral side permanent magnet It can prevent appropriately that a magnetic circuit short circuit arises between a side permanent magnet.

  According to the electric motor of the first aspect of the present invention, with respect to the bottom part and the peripheral wall part formed in a substantially bottomed cylindrical shape, from the position where the outer peripheral side permanent magnet is fixed in the peripheral wall part, via the peripheral wall part and the bottom part. By providing a magnetic flux short-circuit suppressing unit having a relatively small magnetic permeability at a predetermined position on the bottom portion on the virtual path toward the rotation axis, the outer peripheral side permanent magnet and the inner peripheral side permanent magnet along the virtual path It is possible to prevent a magnetic circuit short circuit from occurring between the two. This suppresses an increase in the distance between the outer peripheral side permanent magnet fixed to the peripheral wall portion and the inner peripheral side permanent magnet of the inner peripheral side rotor, and appropriately sets the variable width of the induced voltage constant. Can be increased.

Furthermore, according to the electric motor of the invention described in claim 2, in a state where the circumferential position of the inner peripheral permanent magnet viewed along the axial direction and the circumferential position of the magnetic flux short-circuit suppressing portion overlap, A magnetic path short circuit occurs between the outer peripheral side permanent magnet and the inner peripheral side permanent magnet along a virtual path from the position where the outer peripheral side permanent magnet is fixed to the rotation axis via the peripheral wall portion and the bottom portion. It can be prevented appropriately.
Furthermore, according to the electric motor of the invention described in claim 3, by making the through hole provided in the bottom part a magnetic flux short-circuit suppressing part, the outer peripheral side permanent is caused by a space having a relatively small magnetic permeability in the through hole. It can prevent appropriately that a magnetic circuit short circuit arises between a magnet and an inner peripheral side permanent magnet.

Furthermore, according to the electric motor of the invention described in claim 4, the concave portion provided in the bottom portion is used as a magnetic flux short-circuit suppressing portion, so that the outer peripheral side permanent magnet and the outer permanent magnet are separated by a space having a relatively small magnetic permeability in the concave portion. It can prevent appropriately that a magnetic circuit short circuit arises between inner peripheral side permanent magnets.
Furthermore, according to the electric motor of the invention described in claim 5, by using the concave portion provided in the bottom portion as a magnetic flux short-circuit suppressing portion, a nonmagnetic material having a relatively small magnetic permeability mounted in the concave portion, It can prevent appropriately that a magnetic circuit short circuit arises between an outer peripheral side permanent magnet and an inner peripheral side permanent magnet.

Hereinafter, an embodiment of an electric motor of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 to 5, for example, the electric motor 10 according to the present embodiment includes substantially inner annular rotors 11 and outer circumferences each having permanent magnets 11 a and 12 a arranged along the circumferential direction. A side rotor 12, a stator (not shown) having a multi-phase stator winding (not shown) for generating a rotating magnetic field for rotating the inner circumference rotor 11 and the outer circumference rotor 12, and the inner circumference side A brushless DC motor including a phase control device 15 connected to the rotor 11 and the outer rotor 12 and controlling a relative phase between the inner rotor 11 and the outer rotor 12. For example, it is mounted on a vehicle such as a hybrid vehicle or an electric vehicle as a drive source, the output shaft of the electric motor 10 is connected to the input shaft of a transmission (not shown), and the driving force of the electric motor 10 is driven through the transmission. (Figure It is adapted to be transmitted substantially).

  When the driving force is transmitted from the driving wheel side to the electric motor 10 during deceleration of the vehicle, the electric motor 10 functions as a generator to generate a so-called regenerative braking force, and the kinetic energy of the vehicle body is converted into electric energy (regenerative energy). to recover. Further, for example, in a hybrid vehicle, the output shaft of the electric motor 10 is connected to a crankshaft of an internal combustion engine (not shown), and the electric motor 10 is used as a generator even when the output of the internal combustion engine is transmitted to the electric motor 10. Functions to generate power generation energy.

  The inner circumferential rotor 11 has a substantially cylindrical inner circumferential rotor core 21 formed by laminating electromagnetic steel sheets such as silicon steel plates, and an outer circumferential portion of the inner circumferential rotor core 21 with a predetermined interval in the circumferential direction. 11a, an inner peripheral side end face plates 22 and 22 having an annular plate shape, and an inner peripheral side shaft member 23. The inner peripheral side permanent magnets 11a,.

A plurality of inner peripheral magnet mounting portions 21a,..., 21a are provided at predetermined intervals in the circumferential direction on the outer peripheral portion of the inner peripheral rotor core 21, and the inner peripheral magnet mounting portions 21a adjacent to each other in the circumferential direction are provided. On the outer peripheral surface 21A of the inner rotor core 21 between 21a, a concave groove 21b extending in parallel with the rotation axis O of the electric motor 10 is formed.
The inner peripheral side magnet mounting portion 21a includes, for example, an inner peripheral side magnet mounting hole 24 penetrating in parallel to the rotation axis O. The inner peripheral side magnet mounting hole 24 is a cross section with respect to a direction (axial direction) parallel to the rotation axis O. However, the inner circumferential side permanent magnet is formed in a substantially rectangular shape having a substantially circumferential direction in the longitudinal direction and a substantially radial direction in the short direction. A magnet 11a is attached.

  The inner peripheral permanent magnet 11a mounted in the inner peripheral magnet mounting hole 24 is magnetized in the thickness direction (that is, the radial direction of the inner peripheral rotor 11), and is adjacent to each inner peripheral magnet mounting hole in the circumferential direction. The inner peripheral side permanent magnets 11a, 11a attached to the 24, 24 are set so that their magnetization directions are different from each other. That is, the inner peripheral side magnet mounting portion 21a to which the inner peripheral side permanent magnet 11a having the N pole on the outer peripheral side is mounted has the inner peripheral side magnet mounting to which the inner peripheral side permanent magnet 11a having the S pole on the outer peripheral side is mounted. The part 21a is adjacent in the circumferential direction via the concave groove 21b.

  The annular plate-like inner peripheral side end face plate 22 is, for example, slightly smaller than the outer diameter of the inner peripheral side rotor core 21 and from the inner peripheral surface of the inner peripheral side magnet mounting hole 24 of the inner peripheral side rotor core 21. The inner diameter of the inner peripheral side rotor core 21 is smaller than the inner peripheral surface of the inner peripheral side magnet mounting hole 24 and slightly larger than the inner diameter of the inner peripheral side rotor core 21. Then, it abuts on the axial end of the inner peripheral permanent magnet 11 a mounted in the inner peripheral magnet mounting hole 24 of the inner rotor core 21. That is, the inner peripheral side permanent magnet 11a is formed by the two inner peripheral side end plates 22 and 22 arranged so as to sandwich the inner peripheral side permanent magnet 11a mounted in the inner peripheral side magnet mounting hole 24 from both sides in the axial direction. Displacement along the axial direction is restricted.

  The inner peripheral side shaft member 23 is formed in, for example, a substantially bottomed cylindrical shape having an outer diameter slightly larger than the inner diameter of the inner peripheral portion of the inner peripheral side rotor core 21, and is formed on the inner peripheral portion of the inner peripheral side rotor core 21. It is press-fitted and fixed in an interference-fitted state. This inner peripheral side shaft member 23 is phase-controlled by inserting inner peripheral side fastening members 25 such as rivets and bolts into a plurality of inner peripheral side fastening holes 23a,..., 23a penetrating the bottom along the axial direction. By being fastened to the device 15, it is connected to the phase control device 15.

  The outer peripheral rotor 12 has a substantially plate-shaped bottom 31a having a central axis coaxial with the rotation axis O, and a plurality of peripheral walls extending in the axial direction from a position at a predetermined interval in the circumferential direction at the outer peripheral end of the bottom 31a. A substantially bottomed cylindrical outer peripheral rotor core 31 having pieces 31b, ..., 31b, and a substantially rectangular plate-shaped outer peripheral side permanent arranged on the outer peripheral surface 31B of each peripheral wall piece 31b of the outer peripheral rotor core 31. A magnet 12a, a substantially cylindrical outer peripheral holding member 32 having an inner peripheral surface in contact with the outer peripheral surface of each outer peripheral permanent magnet 12a, and an outer peripheral shaft member 33 are configured.

The outer rotor core 31 is formed in a substantially bottomed cylindrical shape by bending a single member made of, for example, a magnetic material.
The bottom portion 31a is provided with a plurality of through holes that penetrate the bottom portion 31a in the thickness direction (that is, the axial direction) as a plurality of magnetic flux short-circuit suppressing portions 35,. Yes.
As will be described later, each magnetic flux short-circuit suppressing unit 35 is provided at a predetermined position of the bottom 31a on a virtual path from each peripheral wall piece 31b to the rotation axis O via the bottom 31a. By changing the relative phase between the circumferential rotor 11 and the outer circumferential rotor 12, it overlaps with the axial end surface 11A of the inner circumferential permanent magnet 11a when viewed along the axial direction. Is set to be possible.

  In addition, positioning protrusions 31c and 31c that protrude radially outward from the outer peripheral surface 31B of the peripheral wall piece 31b are provided at both ends in the peripheral direction of each peripheral wall piece 31b of the outer peripheral rotor core 31. And the outer peripheral side permanent magnet 12a arrange | positioned on the outer peripheral surface 31B of the surrounding wall piece 31b is positioned so that it may be pinched | interposed from the both sides of the circumferential direction by the two positioning protrusions 31c and 31c of the surrounding wall piece 31b, and the circumferential direction Displacement along is restricted.

  The outer peripheral side permanent magnets 12a supported by the peripheral wall pieces 31b are magnetized in the thickness direction (that is, the radial direction of the outer peripheral rotor 12) and are supported by the peripheral wall pieces 31b and 31b adjacent in the circumferential direction. The permanent magnets 12a and 12a are set so that their magnetization directions are different from each other. That is, the peripheral wall piece 31b supporting the outer peripheral side permanent magnet 12a having the N pole on the outer peripheral side is provided with the slit 31d having a predetermined circumferential width on the peripheral wall piece 31b supporting the outer permanent magnet 12a having the S pole on the outer peripheral side. And are adjacent to each other in the circumferential direction.

And the outer peripheral side rotor core 31 which supports the outer peripheral side permanent magnet 12a by each peripheral wall piece 31b is the inner periphery of an internal diameter provided with a predetermined interference with respect to the outer diameter set by the outer peripheral surface of each outer peripheral side permanent magnet 12a. It is press-fitted into the inner peripheral portion of the outer peripheral side holding member 32 having a surface and is fixed in an interference-fitted state. Thereby, each outer peripheral side permanent magnet 12a is fixed by being sandwiched from both sides in the radial direction by the inner peripheral surface of the outer peripheral side holding member 32 and the outer peripheral surface 31B of each peripheral wall piece 31b.
In addition, the outer peripheral side holding member 32 is formed in a substantially cylindrical shape in which, for example, the radial thickness at an appropriate position in the axial direction has a predetermined uniform thickness.

  The outer peripheral side shaft member 33 is formed, for example, in a substantially annular plate shape that is fixed integrally with the bottom 31a of the outer peripheral side rotor core 31, and an output shaft (not shown) that outputs the driving force of the outer peripheral side rotor 12 to the outside. It is connected to the. In addition, the outer peripheral side shaft member 33 is disposed, for example, inside a substantially bottomed cylindrical outer peripheral side rotor iron core 31, and has a plurality of outer peripheral side fastening holes 33a that penetrate the outer peripheral side shaft member 33 along the axial direction. , 33a and a plurality of outer peripheral side through holes 31e,..., 31e penetrating through the bottom 31a of the outer peripheral rotor core 31 so as to communicate with the outer peripheral side fastening holes 33a,. The outer peripheral side fastening member 34 such as a bolt is fastened to be connected to the phase control device 15.

The inner circumferential rotor 11 is disposed, for example, inside a substantially bottomed cylindrical outer rotor core 31, and the inner circumferential rotor 11 and the outer circumferential rotor 12 have a rotating shaft whose electric axis is the electric motor 10. It arrange | positions so that it may become coaxial with the rotating shaft O. And each inner peripheral side magnet mounting hole 24, ..., 24 of the inner peripheral side rotor 11 and each peripheral wall piece 31b, ..., 31b of the outer peripheral side rotor 12 are radial direction of each rotor 11,12. They are formed so that they can be arranged to face each other.
Thereby, the state of the electric motor 10 is changed between the inner peripheral side permanent magnet 11a of the inner peripheral side rotor 11 and the outer peripheral side according to the relative positions of the inner peripheral side rotor 11 and the outer peripheral side rotor 12 around the rotation axis O. From the field-weakening state in which the magnetic poles of the same polarity with the outer peripheral side permanent magnet 12a of the rotor 12 are arranged to face each other (that is, the inner peripheral side permanent magnet 11a and the outer peripheral side permanent magnet 12a are arranged as a counter electrode), The magnetic poles of different polarities of the inner peripheral permanent magnet 11a of the rotor 11 and the outer peripheral permanent magnet 12a of the outer rotor 12 are opposed to each other (that is, the inner peripheral permanent magnet 11a and the outer peripheral permanent magnet 12a are the same). It is possible to set an appropriate state over the strong field state that is pole-arranged.
In particular, in the weak field state and the strong field state, the long side of the inner peripheral permanent magnet 11a and the long side of the outer peripheral permanent magnet 12a are set to face each other in the cross section with respect to the axial direction.

And each magnetic flux short circuit suppression part 35 provided in the bottom part 31a of the outer peripheral side rotor iron core 31 has the circumferential direction position which has a phase equivalent to the outer peripheral side permanent magnet 12a supported by each peripheral wall piece 31b, and inner peripheral side It arrange | positions in the radial direction position which can be overlapped facing the axial direction end surface 11A of each inner peripheral side permanent magnet 11a of the rotor 11. FIG.
That is, for example, as shown in FIG. 6, in the field weakening (maximum weakening phase) state and the field strengthening (maximum strongening phase) state, each magnetic flux short-circuit suppressing unit 35 is disposed to face each outer peripheral permanent magnet 12a. The area overlapping each other on the end surface 11A in the axial direction of each inner peripheral side permanent magnet 11a is maximized, and between the permanent magnets 11a, 12a arranged to face each other, the outer peripheral side permanent magnet 12a passes through the peripheral wall piece 31b and the bottom 31a. The area of the bottom 31a (for example, the region A1 shown in FIG. 6) that overlaps the axial end surface 11A of the inner peripheral permanent magnet 11a on the virtual path toward the inner peripheral permanent magnet 11a is minimized. It is formed as follows.
Accordingly, as shown in FIG. 7, for example, in the intermediate (intermediate phase) state between the weak field state and the strong field state, the bottom portion overlapping the axial end surface 11A of the inner peripheral permanent magnet 11a. The area of the region 31a (for example, the region B1 shown in FIG. 6) becomes relatively large.

Thus, for example, as in the embodiment shown in FIG. 8, by providing the magnetic flux short-circuit suppressing portion 35 on the bottom 31a made of a magnetic material, for example, Comparative Example 1 in which the magnetic flux short-circuit suppressing portion 35 is not provided on the bottom 31a made of a magnetic material, for example. As compared with the above, the induced voltage constant in the strong field state increases, the induced voltage constant in the weak field state decreases, and the variable width of the induced voltage constant increases.
In this embodiment, each induced voltage constant in the strong field state and the weak field state depends on the size and position of the magnetic flux short-circuit suppressing unit 35, for example, Comparative Example 2 in which the bottom 31a is formed of a nonmagnetic material. And the induced voltage constant in Comparative Example 1 change, and the induced voltage constant is appropriately changed as the phase changes from the strong field state to the weak field state. It changes in a decreasing trend according to the function form.
For example, Comparative Example 3 shown in FIG. 8 is a case where the induced voltage constant becomes a predetermined fixed value by fixing the relative phases of the inner rotor 11 and the outer rotor 12. .

  The phase control device 15 is disposed inside, for example, a substantially bottomed cylindrical inner peripheral shaft member 23, and at least one of the inner peripheral rotor 11 and the outer peripheral rotor 12 is electrically or hydraulically driven. An actuator that changes the relative phase between the inner circumferential rotor 11 and the outer circumferential rotor 12 by rotating around the rotation axis O is provided.

  The stator (not shown) is formed in, for example, a substantially cylindrical shape facing the outer periphery of the outer rotor 12 and is fixed to, for example, a vehicle transmission housing (not shown).

  As described above, according to the electric motor 10 according to the present embodiment, the outer peripheral rotor 12 includes, for example, a bottom portion 31a having a central axis coaxial with the rotation axis O by bending molding of a single member, and the bottom portion. 31b is formed in a substantially bottomed cylindrical shape including a plurality of peripheral wall pieces 31b,..., 31b extending in a direction substantially parallel to the rotation axis O from the outer peripheral end of 31a, and the outer peripheral side permanent magnet 12a is supported by each peripheral wall piece 31b. Therefore, for example, the bottom 31a and each peripheral wall piece 31b are separate and independent members that are connected to each other by a fastening member or the like, and are formed into a substantially bottomed cylindrical shape, while ensuring a desired rigidity. The thickness of the bottom 31a and the peripheral wall piece 31b, particularly the radial thickness of the peripheral wall piece 31b, can be easily prevented from increasing.

Moreover, since the bottom 31a of the outer rotor core 31 is connected to the output shaft O via the outer shaft member 33, the driving force of the outer rotor 12 is not required without increasing the thickness of the bottom 31a itself. Can be ensured to have a desired rigidity required for properly transmitting to the output shaft O.
Thereby, it is suppressed that the distance between the outer peripheral side permanent magnet 12a supported by the peripheral wall piece 31b and the inner peripheral side permanent magnet 11a of the inner peripheral side rotor 11 is increased, and the induced voltage constant is variable. The width can be increased.
Further, in the weak field (maximum weakening phase) state and the strong field (maximum strong phase) state, they overlap each other facing the axial end surface 11A of each inner peripheral side permanent magnet 11a disposed to face each outer peripheral side permanent magnet 12a. By forming each magnetic flux short-circuit suppressing portion 35 having the largest area on the bottom portion 31a, for example, compared with the case where the magnetic flux short-circuit suppressing portion 35 is not provided on the bottom portion 31a made of a magnetic material, an induced voltage in the strong field state As the constant increases, the induced voltage constant in the field-weakening state decreases, and the variable width of the induced voltage constant increases.

  Further, in the outer circumferential rotor 12, by providing a slit 31d having a predetermined circumferential width between the circumferential wall pieces 31b, 31b adjacent in the circumferential direction, the inner circumferential rotor 11 which is not in a mutually opposed relationship is provided. It is possible to suppress the occurrence of a short circuit between the magnetic poles of the peripheral permanent magnet 11a and the outer peripheral permanent magnet 12a of the outer rotor 12.

  Further, by providing the concave groove 21b having a relatively small magnetic permeability between the inner peripheral side permanent magnets 11a, 11a adjacent in the circumferential direction in the inner peripheral side rotor core 21, the inner peripheral side permanent magnets that are not in a mutually opposed relationship. Magnetic path short circuit between the magnetic poles of the magnet 11a and the outer peripheral permanent magnet 12a (for example, between the magnetic poles of the inner peripheral permanent magnet 11a and the outer peripheral permanent magnet 12a arranged so as to straddle the concave groove 21b). Can be prevented from occurring.

  The inner rotor 11 and the outer rotor 12 are provided with substantially rectangular plate-like permanent magnets 11a, 12a along the circumferential direction, and the permanent magnets 11a, 12a are parallel to the rotation axis O. By setting so that the rotors 11 and 12 can be arranged so as to face each other along the radial direction of the rotors 11 and 12 in a cross section with respect to the direction, the magnetic fluxes of the permanent magnets 11a and 12a 21 and 31) can be suppressed. Thereby, generation | occurrence | production of an iron loss is suppressed, for example, the amount of interlinkage magnetic flux in which the field magnetic flux by the outer peripheral side permanent magnet 12a of the outer peripheral side rotor 12 is linked with the stator winding of a stator is changed to the inner peripheral side rotor. 11 can be efficiently increased or decreased by the field magnetic flux generated by the inner peripheral permanent magnet 11a. In the field-enhanced state, the torque constant (that is, torque / phase current) of the electric motor 10 can be set to a relatively high value without reducing the current loss during operation of the electric motor 10, or The maximum torque value output from the electric motor 10 can be increased without changing the maximum value of the output current of an inverter (not shown) that controls energization of the stator windings.

  In addition, the magnitude of the field magnetic flux interlinking the stator winding 13a can be continuously changed, and the induced voltage constant of the electric motor 10 can be continuously changed to an appropriate value. As a result, it is possible to continuously change the values of the rotational speed and torque at which the electric motor 10 can be operated, and it is possible to expand the range of the rotational speed and torque that can be operated. Furthermore, the maximum value of the operation efficiency of the electric motor 10 can be increased, and the high efficiency region where the operation efficiency is equal to or higher than the predetermined efficiency can be expanded.

In the above-described embodiment, the through hole penetrating the bottom portion 31a in the thickness direction is provided as the magnetic flux short-circuit suppressing portion 35. However, the present invention is not limited thereto. For example, a recess is provided on the surface of the bottom portion 31a. A space having a relatively small magnetic permeability provided in the recess may be used as the magnetic flux short-circuit suppressing unit 35.
Further, in this case, a nonmagnetic material may be mounted in the recess formed in the bottom 31a.

  In the above-described embodiment, the outer rotor core 31 is formed into a substantially bottomed cylindrical shape by bending a single member that is a magnetic material. However, the present invention is not limited to this. The peripheral wall piece 31b is an independent member, and may be connected by a fastening member or the like to be formed into a substantially bottomed cylindrical shape. In this case, the fastening member may be a nonmagnetic material, and the mounting hole of the bottom portion 31a to which the fastening member is mounted may be used as the magnetic flux short-circuit suppressing unit 35.

  In the above-described embodiment, the outer peripheral side permanent magnet 12a is arranged on the outer peripheral surface 31B of the peripheral wall piece 31b. However, the present invention is not limited to this, for example, a magnet mounting that extends in the axial direction inside the peripheral wall piece 31b. It may be attached to the hole.

In the above-described embodiment, the slit 31d is provided between the circumferential wall pieces 31b and 31b adjacent in the circumferential direction. However, the present invention is not limited to this. For example, the axial direction of the circumferential wall pieces 31b and 31b adjacent in the circumferential direction is provided. The tip portions β and β may be connected. That is, in this modified example, the outer peripheral rotor 12 includes a substantially plate-shaped bottom portion 31a having a central axis coaxial with the rotation axis O, and a cylindrical peripheral wall portion extending in a substantially axial direction from the outer peripheral end of the bottom portion 31a. And an elongated hole penetrating in the radial direction at a predetermined interval in the circumferential direction on the circumferential surface of the circumferential wall portion and extending from the axial proximal end portion toward the axial distal end portion, and adjacent in the circumferential direction The outer peripheral permanent magnet 12a is supported on the peripheral wall portion between the long holes.
Thereby, the rigidity in the axial direction front-end | tip part (beta) side of each surrounding wall piece 31b can be increased.

  In the above-described embodiment, the outer peripheral side permanent magnet 12a is disposed on the outer peripheral surface 31B of the peripheral wall piece 31b of the outer peripheral side rotor iron core 31. However, the present invention is not limited to this. , And a substantially cylindrical rotor core having an inner peripheral surface having an inner diameter with a predetermined allowance with respect to the outer diameter set by the outer peripheral surface 31B of each peripheral wall piece 31b, ..., 31b of the outer peripheral rotor core 31. , 12a are mounted at predetermined intervals in the circumferential direction on the inner peripheral portion of the rotor core, and the peripheral wall pieces 31b,..., 31b of the outer rotor core 31 are attached to the inner peripheral portion of the rotor core. May be press-fitted.

It is a principal part perspective view which decomposes | disassembles and shows the principal part of the inner peripheral side rotor of an electric motor which concerns on one Embodiment of this invention, and an outer peripheral side rotor. It is a principal part perspective view which decomposes | disassembles and shows the principal part of the inner peripheral side rotor of an electric motor which concerns on one Embodiment of this invention, and an outer peripheral side rotor. It is a principal part perspective view of the inner peripheral side rotor and outer peripheral side rotor of the electric motor which concerns on one Embodiment of this invention. It is a principal part perspective view of the inner peripheral side rotor and outer peripheral side rotor of the electric motor which concerns on one Embodiment of this invention. It is sectional drawing of the inner peripheral side rotor and outer peripheral side rotor of the electric motor which concerns on one Embodiment of this invention. It is a figure which shows the relative position of the magnetic flux short circuit suppression part and each permanent magnet in the field weakening (maximum weakening phase) state and strong field (maximum strongening phase) state of the electric motor which concerns on one Embodiment of this invention. It is a figure which shows the relative position of the magnetic flux short circuit suppression part and each permanent magnet in the intermediate | middle (intermediate phase) state of the electric motor which concerns on one Embodiment of this invention. It is a graph which shows the change of the induced voltage constant according to the relative phase of the inner peripheral side rotor and outer peripheral side rotor in the Example and Comparative Examples 1-3 with respect to the electric motor which concerns on one Embodiment of this invention. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric motor 11 Inner peripheral side rotor 11a Inner peripheral side permanent magnet 12 Outer peripheral side rotor 12a Outer peripheral side permanent magnet 15 Phase control apparatus (rotating means)
31a Bottom part 31b Perimeter wall piece (peripheral wall part)
31B Outer peripheral surface (surface)
35 Magnetic flux short-circuit suppressor

Claims (5)

The rotation axes of the inner peripheral rotor having the inner peripheral permanent magnet arranged along the circumferential direction and the outer rotor having the outer permanent magnet arranged along the circumferential direction are coaxially arranged. And
The relative phase between the inner circumferential rotor and the outer circumferential rotor is changed by rotating at least one of the inner circumferential rotor and the outer circumferential rotor about the rotation axis. An electric motor with possible turning means,
The outer peripheral rotor is formed in a substantially bottomed cylindrical shape including a peripheral wall portion to which the outer peripheral permanent magnet is fixed, and a bottom portion made of a magnetic material connected to the peripheral wall portion,
Comprising a magnetic flux short-circuit suppressing portion at a predetermined position of the bottom portion on a virtual path toward the rotary shaft via the peripheral wall portion and the bottom portion from a position where the outer peripheral permanent magnets are fixed in the peripheral wall,
The predetermined position is a position overlapping the axial end surface of the inner peripheral permanent magnet when viewed along the axial direction;
The magnetic flux short-circuit suppressing unit includes an electric motor, characterized in Rukoto that having a small magnetic permeability as compared with the portion other than the magnetic flux short circuit suppressing portion of the bottom portion. The magnetic flux short-circuit suppressing unit is viewed along a direction parallel to the rotation axis by changing a relative phase between the inner rotor and the outer rotor by the rotating means. 2. The electric motor according to claim 1, wherein a circumferential position of the inner peripheral side permanent magnet and a circumferential position of the magnetic flux short-circuit suppressing unit are overlapped with each other. 3. The electric motor according to claim 1, wherein the magnetic flux short-circuit suppressing unit is a through-hole penetrating the bottom in a thickness direction. The electric motor according to claim 1, wherein the magnetic flux short-circuit suppressing unit is a concave portion provided on a surface of the bottom portion. The electric motor according to claim 4, comprising a member made of a nonmagnetic material attached to the recess.

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