JP2012075288A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for changing magnetic flux of a permanent magnet of a rotor which is interlinked with a stator coil in a structure which can sufficiently use reluctance torque.SOLUTION: A rotary electric machine includes: a stator 3; and a first rotor 20 and a second rotor 10, which can adjust a relative position in a circumferential direction. A permanent magnet 24 supplying field magnetic flux is buried in a rotor core 21 of the first rotor 20. The second rotor 10 is arranged between the stator 3 and the first rotor 20. The rotor core 11 of the second rotor 10 includes a gap 7 between magnetic poles, which becomes magnetic resistance to the field magnetic flux. The gap 7 between the magnetic poles is divided and formed into two by a bridge magnetic path 8 which is adjacent in the circumferential direction and is arranged in a position confronted with a center between the magnetic poles of the permanent magnet 24 in the different magnetic pole direction in a state where the relative positions of both the rotors 10 and 20 are in the prescribed reference positions.

Description

  The present invention relates to a variable magnetic flux type rotating electrical machine that includes a plurality of rotors whose relative positions in the circumferential direction can be adjusted to change a field flux.

  An interior permanent magnet synchronous motor (IPMSM) having a rotor with a permanent magnet embedded therein is widely used. In IPMSM, since the permanent magnet is normally fixed to the rotor core, the magnetic flux generated from the rotor is constant. As the rotational speed of the rotor increases, the induced voltage generated in the stator coil increases, and if the induced voltage exceeds the drive voltage, control may become impossible. In order to avoid this, field weakening control that substantially weakens the magnetic field from the rotor is performed above a certain rotational speed. However, if field-weakening control is performed, the current flowing through the stator coil increases with respect to the torque output from the rotating electrical machine, resulting in increased copper loss and reduced efficiency. Further, if the magnetic flux reaching the stator from the permanent magnet remains constant, the iron loss generated in the stator core also increases in the region where the rotational speed of the rotor is high, and the efficiency decreases.

  Therefore, a technique has been proposed in which the magnetic flux reaching the stator from the permanent magnet provided in the rotor is changed according to the rotational speed of the rotor. In U.S. Pat. No. 4,885,493 (Patent Document 1), a rotating electrical machine having a flux diversion member 34 between a rotor 32 and a stator assembly 30 is disclosed. Is disclosed. This magnetic flux path changing member has non-magnetic end rings (end rings 36, 38) at both ends in the direction along the shaft (shaft 18), and these end rings are rotatably held by the shaft. By changing the relative position of the rotor and the magnetic flux path changing member, the magnetic flux path from the permanent magnet of the rotor to the stator changes, and the magnetic flux reaching the stator changes (Patent Document 1: Fig. 1, Fig. 2a). , Fig.2b, second column, etc.).

  By the way, in the IPMSM, due to the arrangement of the permanent magnet with respect to the rotor, the magnetic characteristics in the direction of the magnetic pole of the permanent magnet and the direction deviated by 90 degrees in electrical angle with respect to this direction (hereinafter referred to as “magnetic pole orthogonal direction” as appropriate). Many of them have saliency that is different from the magnetic characteristics of. That is, the magnetic resistance (reluctance) of the rotor as seen from the rotating magnetic flux generated by the current flowing through the stator coil is not uniform, the magnetic resistance in the direction of the permanent magnet is large, and the magnetic resistance is small in the direction perpendicular to the magnetic pole. For this reason, the magnetic flux of the rotating magnetic field in the direction perpendicular to the magnetic pole passes through the inside of the rotor core, and the rotor core is attracted by this magnetic flux to generate torque. This torque is called reluctance torque. Thus, a rotating electrical machine having saliency can use reluctance torque in addition to magnet torque generated by attractive repulsion between a field magnetic flux formed by a magnetic field of a permanent magnet and a rotating magnetic field based on a current flowing through a stator coil. However, in order to change the magnetic flux reaching the stator from the permanent magnet as described above, if the magnetic flux path is simply changed using a magnetic flux path changing member or the like, the magnetic flux path for obtaining the reluctance torque is also affected. There is a case. As a result, the reluctance torque cannot be fully utilized, and the efficiency of the rotating electrical machine may be reduced.

US Pat. No. 4,885,493

  In view of the above-described background, it is desired to provide a technology that can change the magnetic flux of the permanent magnet of the rotor that is linked to the stator coil with a structure that can sufficiently utilize the reluctance torque.

In view of the above problems, the characteristic configuration of the rotating electrical machine according to the present invention is as follows:
A rotating electrical machine comprising a stator having a stator coil, and a first rotor and a second rotor capable of adjusting a relative position in the circumferential direction,
The first rotor includes a rotor core and a permanent magnet that is embedded in the rotor core and provides a magnetic field flux interlinked with the stator coil.
The second rotor includes a rotor core and is disposed between the stator and the first rotor,
The rotor core of the second rotor includes a gap between magnetic poles that becomes a magnetic resistance with respect to the field magnetic flux,
The gap between the magnetic poles is a bridge magnetic path disposed at a position adjacent to the central portion between the magnetic poles of the permanent magnets adjacent in the circumferential direction and having different magnetic pole directions in a state where the relative positions of the two rotors are at the reference position. Is divided into at least two parts.

  In the state where the relative position of both rotors is at the reference position, the magnetic flux leakage between the magnetic poles of adjacent permanent magnets is suppressed by the gap between the magnetic poles which becomes a magnetic resistance to the field magnetic flux, and the interlinkage magnetic flux to the stator coil Can be secured. That is, at the reference position, the magnet torque can be generated using the magnetic flux of the permanent magnet to the maximum. Here, the magnetic flux of the rotating magnetic field that generates the reluctance torque has a phase that differs by 90 degrees in electrical angle with respect to the field magnetic flux generated by the permanent magnet, and the magnetic path is the place where the gap between the magnetic poles is provided. That is, the magnetic flux of the rotating magnetic field that generates reluctance torque is hindered by the gap between the magnetic poles. However, according to this characteristic configuration, since the gap between the magnetic poles is divided by the bridge magnetic path, the magnetic flux that generates the reluctance torque is well guided to the rotor core of the first rotor through the bridge magnetic path. It is burned. Thus, in a state where the relative position is at the reference position, both the magnet torque and the reluctance torque can be used well. The relative position in the circumferential direction of the first rotor and the second rotor can be adjusted, and the position of the gap between the magnetic poles on the rotor side changes according to the relative position. The magnetic flux changes. Further, the bridge magnetic path becomes a path for the magnetic flux at the reference position, and the magnetic flux of the rotating magnetic field that generates the reluctance torque at the position deviated from the reference position is hardly disturbed by the gap between the magnetic poles. Therefore, according to this characteristic configuration, the reluctance torque can be fully utilized regardless of the relative position between the first rotor and the second rotor, and the magnetic flux of the permanent magnet of the rotor interlinked with the stator coil can be obtained. A changeable rotating electrical machine can be obtained.

  Preferably, the rotor core of the first rotor of the rotating electrical machine according to the present invention is such that the relative position of both rotors is in a phase shifted by 90 degrees in electrical angle from the reference position. A magnetic pole gap is provided at a position facing the bridge magnetic path and serves as a magnetic resistance with respect to the field magnetic flux. In the phase where the relative position of both rotors is shifted by 90 degrees from the reference position in electrical angle, the amount of field flux of the permanent magnet that is bypassed through the second rotor is maximized. The field flux can be reduced most. However, by providing the bridge magnetic path as described above, the bridge magnetic path corresponds to the magnetic path of the field magnetic flux by the permanent magnet in the phase where the relative positions of the two rotors are shifted by 90 degrees in electrical angle. For this reason, the magnetic flux of the permanent magnet passing through the bridge magnetic path is linked to the stator coil. Therefore, the first rotor is preferably provided with a magnetic pole gap at a position facing the bridge magnetic path in this state. Since this magnetic pole gap becomes a magnetic resistance to the field magnetic flux passing through the bridge magnetic path, the leakage magnetic flux passing through the bridge magnetic path is reduced. As a result, since the bridge magnetic path is provided to obtain the reluctance torque at the reference position, the effect of reducing the field magnetic flux at the phase shifted by 90 degrees in electrical angle is suppressed, and the field at the phase is suppressed. The effect of reducing magnetic flux can be enhanced.

  The rotor core of the first rotor has a structure in which the magnetic flux of the permanent magnet and the magnetic flux generated by the stator coil pass well, and in the state where the relative position of both rotors is in a phase shifted by 90 degrees in electrical angle from the reference position. It is desirable that the structure prevent the magnetic flux of the permanent magnet that passes through the magnetic path. Therefore, it is preferable that the magnetic pole gap is formed in such a shape that the rotor core of the first rotor can satisfy such a structure. For example, if the magnetic pole gap is formed in a shape similar to the shape of the region sandwiched between the permanent magnets in the same magnetic pole direction adjacent in the circumferential direction in the cross section perpendicular to the axis, a portion that becomes a magnetic path in the rotor core And a portion to be a magnetic flux barrier are formed with a good balance.

  Preferably, the magnetic flux changing region including the bridge magnetic path and the pair of gaps between the magnetic poles of the rotating electrical machine according to the present invention and the bridge magnetic path are on the side where the second rotor and the stator face each other. The ratio of the arc to the circumference is larger than the ratio of the arc to the circumference on the side where the first rotor and the second rotor face each other. In this way, the circumferential surface facing the teeth on the stator side can be made wider, so that the magnetic flux from the stator coil to the rotor cores of the first rotor and the second rotor can be favorably guided.

  Similar to the magnetic pole gap, it is preferable that the portion serving as the magnetic path and the portion serving as the magnetic flux barrier are formed in a well-balanced manner in the magnetic flux change region. For example, when the magnetic flux change region and the bridge magnetic path are similar, a well-balanced shape is obtained. However, as described above, when the circumferential surface facing the teeth on the stator side is widened, it is naturally not a completely similar shape but a substantially similar shape. At this time, for example, when the gap between the magnetic poles is divided into two by the bridge magnetic path in the magnetic flux change region, each magnetic pole gap formed at both ends in the circumferential direction of the magnetic flux change region It is preferable to form in a parallelogram shape. In this way, in particular, the magnetic resistance becomes equal to the leakage magnetic flux that tries to pass through the second rotor in the circumferential direction. In addition, a portion that becomes a magnetic path in the magnetic flux change region and a portion that becomes a magnetic flux barrier are formed in a well-balanced manner.

Skeleton diagram of relative position conversion mechanism for changing relative position of first rotor and second rotor The figure which shows the field magnetic flux (d-axis magnetic flux) in the state whose relative position is a reference position (0 degree) The figure which shows the magnetic flux (q-axis magnetic flux) of a rotating magnetic field in the state where a relative position is a reference position. The figure which shows d-axis magnetic flux in the state whose relative position is 90 degree | times with respect to a reference position. The figure which shows the q-axis magnetic flux in the state whose relative position is 90 degree | times with respect to a reference position. The figure which shows d axis magnetic flux in the state where a relative position is 45 degrees to a standard position The figure which shows q-axis magnetic flux in the state where a relative position is 45 degree | times with respect to a reference position. Enlarged view of magnetic flux change area including gap between magnetic poles and bridge magnetic path Graph showing the improvement rate of reluctance torque at the relative position of the case Graph showing the effect of reducing copper loss

  Hereinafter, embodiments of a rotating electrical machine according to the present invention will be described with reference to the drawings. In the present embodiment, a variable magnetic flux type rotating electrical machine in which the field magnetic flux linked to the stator coil changes according to the circumferential relative positions of the first rotor and the second rotor will be described as an example. As shown in FIG. 1, the rotating electrical machine 2 is an inner rotor type rotating electrical machine having two rotors whose relative positions are variable. In this embodiment, the rotor 4 is opposed to the stator 3, and is a second rotor 10 that is an outer rotor that is disposed relatively outside, and a first rotor 20 that is an inner rotor disposed relatively inside. Composed. Moreover, although mentioned later for details, the 1st rotor 20 is provided with the permanent magnet (code | symbol 24 mentioned later using FIG. 2 etc.) embedded inside the 1st rotor core 21 and the 1st rotor core 21. . The second rotor 10 includes a second rotor core 11.

  In the following description, unless otherwise specified, the “axial direction L”, “radial direction R”, and “circumferential direction” are the axes of the first rotor core 21 and the second rotor core 11 that are coaxially arranged (that is, the rotation axis). It is defined as a standard. Further, in the following description, “axial first direction L1” represents the left side along the axial direction L in FIG. 1, and “axial second direction L2” represents the right side along the axial direction L in FIG. Shall. The “inner diameter direction R1” represents a direction toward the inner side (axial center side) of the radial direction R, and the “outer diameter direction R2” represents a direction toward the outer side (stator side) of the radial direction R.

[Structure of rotating electrical machine and drive unit]
As shown in FIG. 1, the rotating electrical machine 2 including the stator 3 and the rotor 4 is accommodated in a case 80. And the rotary electric machine 2 comprises the drive device 1 with the relative position adjustment mechanism 50 which adjusts the relative position of the circumferential direction of the 1st rotor 20 and the 2nd rotor 10, and the drive force (synonymous with torque) of the rotary electric machine 2 is comprised. The output shaft 6 can be transmitted.

  The stator 3 is fixed to the inner surface of the peripheral wall portion of the case 80. The stator 3 includes a stator core 3 a and a coil (stator coil) 3 b wound around the stator core 3 a and constitutes an armature of the rotating electrical machine 2. In this example, the stator core 3a is formed by laminating a plurality of electromagnetic steel plates, and is formed in a cylindrical shape. A rotor 4 as a field magnet having a permanent magnet is disposed on the inner radial direction R1 side of the stator 3. The rotor 4 is supported by the case 80 so as to be rotatable around the rotation axis, and rotates relative to the stator 3. The rotor 4 includes a first rotor 20 and a second rotor 10 that can adjust the relative position in the circumferential direction.

  The first rotor 20 includes a first rotor core 21 that is located on the radial direction R1 side opposite to the stator 3 with respect to the second rotor 10 and is coaxially disposed with the second rotor core 11. The first rotor core 21 is disposed so as to overlap the second rotor core 11 when viewed in the radial direction R. In this example, the first rotor core 21 has the same length L in the axial direction as the second rotor core 11 and is disposed so as to completely overlap the second rotor core 11 when viewed in the radial direction R. In the present example, the first rotor core 21 is configured by laminating a plurality of electromagnetic steel plates. The first rotor 20 includes a first rotor core support member 22 that supports the first rotor core 21 and rotates integrally with the first rotor core 21. The first rotor 20 includes a permanent magnet 24 that is embedded in the first rotor core 21 and provides a field magnetic flux interlinking with the coil 3b.

  The second rotor 10 includes a second rotor core 11 and is disposed between the stator 3 and the first rotor 20. The second rotor 10, which is an outer rotor, is disposed on the inner radial direction R 1 side with respect to the stator 3 so as to face the stator 3 in the radial direction R, and is disposed in a cylindrical shape coaxially with the first rotor core 21. The second rotor core 11 is provided. The second rotor core 11 is also configured by laminating a plurality of electromagnetic steel plates. Further, the second rotor core 11 is supported by being sandwiched from both sides in the axial direction L by a second rotor core support member 12 that rotates integrally with the second rotor core 11. A sensor rotor of a rotation sensor (not shown), for example, is attached to a portion of the second rotor core support member 12 on the side in the second axial direction L2 with respect to the second rotor core 11 so as to rotate integrally. The rotation sensor detects the rotational position (electrical angle) and rotational speed of the rotor 4 with respect to the stator 3.

  The rotating electrical machine 2 is a variable magnetic flux type, and at least one of the first rotor core 21 and the second rotor core 11 is provided with a permanent magnet. In the present embodiment, permanent magnets are provided only in the first rotor core 21, and end plates for preventing permanent magnets provided in the first rotor core 21 from being disposed on both sides in the axial direction L of the first rotor core 21. Is provided. The end plate on the second axial direction L2 side is positioned and held in the axial direction L with respect to the first rotor core support member 22 by a flange portion formed on the first rotor core support member 22. Further, the end plate on the side in the first axial direction L1 is positioned and held in the axial direction L with respect to the first rotor core support member 22 by caulking structure, welding, or retaining by another member.

  The second rotor core 11 is formed with a gap as a flux barrier that provides a magnetic resistance to the magnetic flux. In the present embodiment, the second rotor core 11 is disposed between the magnetic poles of the permanent magnets 24 adjacent in the circumferential direction in a state where the relative positions of the rotors 11 and 21 are at a predetermined reference position, and is magnetic with respect to the field flux. A gap between the magnetic poles serving as a resistor (reference numeral 7 described later using FIG. 2 and the like) is provided. Due to the gap 7 between the magnetic poles, the interlinkage magnetic flux reaching the coil 3 b of the stator 3 changes according to the relative position in the circumferential direction between the first rotor 20 and the second rotor 10. Although details will be described later, the permanent magnet 24 and the gap 7 between the magnetic poles leak from the permanent magnet 24 through the second rotor core 11 according to the relative position in the circumferential direction between the first rotor 20 and the second rotor 10. Transition is possible between a state in which the magnetic flux (field magnetic flux) reaching the stator 3 is increased by suppressing the magnetic flux and a state in which the leakage magnetic flux passing through the second rotor core 11 is increased and the magnetic flux reaching the stator 3 is reduced. Is arranged. That is, the interlinkage magnetic flux reaching the coil 3 b of the stator 3 can be adjusted by adjusting the relative position in the circumferential direction between the first rotor 20 and the second rotor 10.

  The relative position adjustment mechanism 50 is a mechanism that adjusts the circumferential relative position between the first rotor core support member 22 and the second rotor core support member 12. As described above, the first rotor core support member 22 rotates integrally with the first rotor core 21, and the second rotor core support member 12 rotates integrally with the second rotor core 11. Therefore, the relative position in the circumferential direction between the first rotor core 21 and the second rotor core 11 is adjusted by the relative position adjusting mechanism 50.

  In the present embodiment, as shown in FIG. 1, the relative position adjustment mechanism 50 includes two differential gear devices (a first differential gear device 51 and a second differential gear device 52). The relative position adjusting mechanism 50 is disposed on the first axial direction L1 side with respect to the rotating electrical machine 2. That is, the relative position adjusting mechanism 50 is disposed on the first axial direction L1 side with respect to both the second rotor core 21 and the second rotor core 11. The first differential gear device 51 and the second differential gear device 52 are arranged such that the first differential gear device 51 is located on the side in the first axial direction L1 with respect to the second differential gear device 52. They are arranged side by side in the axial direction L.

  In the present embodiment, the first differential gear device 51 is configured by a single pinion type planetary gear mechanism including three rotating elements. That is, the first differential gear device 51 includes a first carrier 51b that supports a plurality of pinion gears, and a first sun gear 51a and a first ring gear 51c that mesh with the pinion gears, respectively, as rotating elements. The first sun gear 51a is drivingly connected so as to rotate integrally with the first rotor core support member 22. The first carrier 51b is drivingly connected so as to rotate integrally with the output shaft 6. As a result, the first rotor core support member 22 is drivingly connected to the output shaft 6 via the relative position adjustment mechanism 50.

  The first ring gear 51c meshes with the worm gear 54 for adjusting the rotation position (circumferential position) of the first ring gear 51c on the outer peripheral surface (the surface facing the radially outward direction R2, hereinafter the same). The rotation position (circumferential position) of the first ring gear 51c can be changed by rotating the worm gear 54 connected to a driving force source such as a motor (not shown). When the rotational position of the first ring gear 51c is adjusted, the worm gear 54 is rotationally driven by a driving force source such as a motor, and the worm gear 54 is fixed except during the adjustment. That is, the first ring gear 51c is in a fixed state except when the rotational position is adjusted.

  In the present embodiment, the second differential gear device 52 is configured by a single pinion type planetary gear mechanism having three rotating elements. That is, the second differential gear device 52 includes a second carrier 52b that supports a plurality of pinion gears, and a second sun gear 52a and a second ring gear 52c that respectively mesh with the pinion gears as rotating elements. The second sun gear 52a is drivingly coupled so as to rotate integrally with the second rotor core support member 12. The second carrier 52b is drivingly coupled so as to rotate integrally with the output shaft 6. Thus, the second rotor core support member 12 is drivingly connected to the output shaft 6 via the relative position adjustment mechanism 50. That is, in this example, both the first rotor core support member 22 and the second rotor core support member 12 are drivingly connected to the common output shaft 6 via the relative position adjustment mechanism 50. Further, the second ring gear 52 c is fixed to the case 80 via the ring-shaped member 55.

  In the present embodiment, the first carrier 51 b and the second carrier 52 b integrally form an integral carrier 53, and the integral carrier 53 is drivingly connected so as to rotate integrally with the output shaft 6. In the present embodiment, the first differential gear device 51 and the second differential gear device 52 are configured to have the same diameter, and the gear ratio of the first differential gear device 51 (= the teeth of the first sun gear 51a). Number / the number of teeth of the first ring gear 51c) and the ratio of the number of teeth of the second differential gear device 52 (= the number of teeth of the second sun gear 52a / the number of teeth of the second ring gear 52c) are set to be equal to each other. Then, except when adjusting the rotational position of the first ring gear 51c, both the first ring gear 51c and the second ring gear 52c are in a fixed state. Therefore, the first rotor core support member 22 drivingly connected to the first sun gear 51a and the second rotor core support member 12 drivingly connected to the second sun gear 52a rotate at the same rotational speed (rotor rotational speed). The rotation speed of the output shaft 6 is decelerated with respect to the rotor rotation speed. That is, in this example, the torque of the rotating electrical machine 2 is amplified and transmitted to the output shaft 6.

  In the present embodiment, the second ring gear 52c is fixed to the case 80, while the first ring gear 51c is adjustable in rotational position. That is, in the two planetary gear mechanisms in which the carriers are integrally formed, one ring gear can be moved relative to the other ring gear in the circumferential direction (that is, relative rotation). With this relative rotation, one sun gear rotates relative to the other sun gear. Therefore, the relative position in the circumferential direction between the first sun gear 51a and the second sun gear 52a can be adjusted by adjusting the rotational position of the first ring rear 51c. As a result, the circumferential relative position between the first rotor core support member 22 and the second rotor core support member 12 can be adjusted.

[Arrangement structure of air gaps for magnetic resistance]
As described above, the rotating electrical machine 2 of the present embodiment adjusts the interlinkage magnetic flux that reaches the coil 3 b of the stator 3 by adjusting the relative position in the circumferential direction between the first rotor 20 and the second rotor 10. Is possible. Hereinafter, the direction of the magnetic flux (field magnetic flux) of the permanent magnet is d-axis, the direction orthogonal to the d-axis is the q-axis, and the magnetic flux of the permanent magnet is generated by the d-axis magnetic flux and the current flowing through the coil 3b. A magnetic flux that generates reluctance torque is referred to as a q-axis magnetic flux. Hereinafter, the d-axis magnetic flux and the q-axis magnetic flux according to the relative positions of the first rotor 20 and the second rotor 10 will be described with reference to FIGS. 2 to 7 are cross-sectional views of the rotor 4 that are orthogonal to each other and roughly corresponding to one cycle of the electrical angle. 2 and 3 show a state in which the relative position is a reference position, and FIGS. 4 and 5 show a state in which the relative position is shifted by 90 degrees in electrical angle with respect to the reference position. 7 and 7 show a state where the relative position is deviated by 45 degrees in electrical angle from the reference position. 2, FIG. 4, and FIG. 6 show the d-axis magnetic flux, and FIGS. 3, 5, and 7 show the q-axis magnetic flux, respectively. In the case of q-axis magnetic flux, a permanent magnet having a magnetic permeability substantially equal to the magnetic permeability in vacuum is equivalent to an air gap (air gap), and thus is illustrated in the form of an air gap.

[Arrangement structure of gap between magnetic poles and bridge magnetic path]
As shown in FIG. 2, the first rotor 20 includes a first rotor core 21 and a permanent magnet 24 that is embedded in the first rotor core 21 and provides a field magnetic flux interlinked with the coil 3 b. The second rotor 10 including the second rotor core 11 is disposed between the stator 3 and the first rotor 20. The second rotor core 11 is disposed between the magnetic poles of the permanent magnets 24 adjacent in the circumferential direction in a state where the relative position between the rotors 10 and 20 is a predetermined reference position of 0 degrees, and has a magnetic resistance with respect to the field flux. The gap 7 between magnetic poles is provided. The gap 7 between the magnetic poles is a bridge magnetic path disposed at a position facing the central portion between the magnetic poles of the permanent magnets 24 adjacent in the circumferential direction and having different magnetic pole directions in a state where the relative position is 0 degrees. 8 is divided into at least two parts. Here, between the magnetic poles in different magnetic pole directions is the circumferential direction between the N pole surface NP of the permanent magnet 24N constituting the N pole of the first rotor 20 and the S pole surface SP of the permanent magnet 24S constituting the S pole. It is an area between. More specifically, the term “between magnetic poles” refers to a region between the end portion in the radially outer direction R2 (the radially outer end) of the N pole surface NP and the radially outer end of the S pole surface SP. The N-pole surface NP and the S-pole surface SP are surfaces that face the radially outer direction R <b> 2 of the magnet 24.

  The gap 7 between the magnetic poles functions as a flux barrier that provides a large magnetic resistance against the leakage magnetic flux passing through the second rotor core 11 in the circumferential direction. As a result, as shown in the one-dot chain line portion A in FIG. 2, this leakage magnetic flux can be significantly suppressed, and the interlinkage magnetic flux of the coil 3b can be secured. As shown in FIG. 2, the field magnetic flux (d-axis magnetic flux) generated by the permanent magnet 24 satisfactorily becomes the interlinkage magnetic flux of the coil 3b. Here, referring to FIG. 4 for comparison, unlike FIG. 2, the inter-magnetic gap 7 is not located between the magnetic poles of the permanent magnet 24 adjacent in the circumferential direction. For this reason, as shown by the one-dot chain line portion A in FIG. 4, the field flux of the permanent magnet 24 is guided in the circumferential direction of the second rotor core 11 having a lower magnetic resistance than the direction of the stator 3. That is, most of the field flux becomes leakage flux, and the linkage flux of the coil 3b of the stator 3 is reduced. In the state where the relative position of both the rotors 10 and 20 is a predetermined reference position of 0 degrees, the gap between the magnetic poles 7 is formed in the second rotor 10 as described above. It can be easily understood that the interlinkage magnetic flux of the coil 3b can be secured.

  Further, the q-axis magnetic flux that generates the reluctance torque is guided from the stator 3 to the first rotor 20 through the bridge magnetic path 8 as shown in FIG. For example, in the one-dot chain line portion A in FIG. 3, if the inter-magnetic gap 7 is continuously formed without forming the bridge magnetic path 8, the inter-magnetic gap 7 is applied to the magnetic flux passing through the radial direction of the rotor 4. It becomes a magnetic resistance and the q-axis magnetic flux is attenuated. As a result, since the reluctance torque is reduced, the efficiency of the rotating electrical machine 2 is reduced. However, as shown in FIG. 3, in the present embodiment, the gap 7 between the magnetic poles is divided by the bridge magnetic path 8, so that the q-axis magnetic flux that generates the reluctance torque passes through the bridge magnetic path 8. Good guidance to one rotor 20. That is, the bridge magnetic path 8 is formed so as to bridge the gap 7 between the magnetic poles in the radial direction, and functions as a q-axis bridge that passes the q-axis magnetic flux in the radial direction. As described above, the relative position shown in FIGS. 2 and 3, that is, the reference position is a relative position where the magnet torque and the reluctance torque can be satisfactorily utilized and the maximum torque can be output.

  FIG. 4 shows the field magnetic flux (d-axis magnetic flux) in a state where the relative positions of the rotors 10 and 20 are shifted by 90 degrees with respect to the reference position. As described above, in this state where the relative position is shifted by 90 degrees with respect to FIG. 2, the gap 7 between the magnetic poles is not located between the magnetic poles of the permanent magnet 24 adjacent in the circumferential direction. For this reason, as shown by the one-dot chain line portion A in FIG. 4, the field flux of the permanent magnet 24 is guided in the circumferential direction of the second rotor core 11, which has a lower magnetic resistance than the direction of the stator 3, and the leakage flux increases. . As a result, the interlinkage magnetic flux of the coil 3b of the stator 3 is reduced, and a field weakening state is obtained. That is, the field weakening control of the rotating electrical machine 2 can be performed without increasing the so-called d-axis current of the current flowing through the coil 3b.

  FIG. 5 shows the q-axis magnetic flux in a state where the relative positions of the rotors 10 and 20 are shifted by 90 degrees with respect to the reference position as in FIG. When the relative position is in this state, there is no inter-magnetic gap 7 between the magnetic poles. Therefore, the radial magnetic flux is not disturbed in the alternate long and short dash line portion A, and the q-axis magnetic flux passes through the second rotor 10 without any problem. 1 is guided to the rotor 20. Referring to FIG. 3 for comparison, the q-axis magnetic flux is guided from the stator 3 to the first rotor 20 at any relative position without being substantially affected by the relative positions of the rotors 10 and 20. You can see that

  As described above with reference to FIGS. 2 to 5, the relative position in the circumferential direction of the first rotor 20 and the second rotor 10 can be adjusted, and the permanent linkage that interlinks with the coil 3 b according to the relative position. The magnetic flux (d-axis magnetic flux) of the magnet changes. However, the q-axis magnetic flux hardly changes regardless of the relative position. Accordingly, the rotating electrical machine 2 that can change the magnetic flux of the permanent magnet 24 of the rotor 4 that is linked to the coil 3b with a structure that can sufficiently utilize the reluctance torque is realized.

  FIG. 6 shows both magnetic fluxes in a state where the relative position is deviated by 45 degrees with respect to the reference position with respect to the fact that the d-axis magnetic flux changes according to the relative positions of the rotors 10 and 20 and the q-axis magnetic flux hardly changes. Supplementary explanation will be made with reference to FIG. FIG. 6 shows a d-axis magnetic flux that is a magnetic flux generated by the permanent magnet 24 as in FIGS. 2 and 4. At the reference position (FIG. 2), the leakage magnetic flux in the circumferential direction is blocked by the divided gap 7 between the magnetic poles at two circumferential positions of the second rotor 10. Therefore, the leakage magnetic flux that bypasses between the magnetic poles is greatly suppressed. On the other hand, in a state where it is deviated by 45 degrees from the reference position (FIG. 6), it is blocked at only one place in the circumferential direction of the second rotor 10 by the divided gap 7 between the magnetic poles. For this reason, compared with the reference position, the d-axis magnetic flux that bypasses between the magnetic poles through the circumferential direction of the second rotor 10 increases. As a result, the flux linkage of the coil 3b is reduced as compared with the reference position, and a field weakening is achieved. On the other hand, the d-axis magnetic flux that bypasses between the magnetic poles through the circumferential direction of the second rotor 10 is less as compared with the state shifted by 90 degrees from the reference position (FIG. 4). Therefore, the degree of weakening the field is less than that in the state of being shifted 90 degrees from the reference position.

  FIG. 7 shows the q-axis magnetic flux when the relative positions of the rotors 10 and 20 are deviated by 45 degrees with respect to the reference position, as in FIG. Even in this state, the magnetic flux passing through the radial direction from the second rotor 10 to the first rotor 20 is almost hindered by the gap 7 between the magnetic poles, as in the state shifted by 90 degrees with respect to the reference position (FIG. 5). Not. Therefore, the q-axis magnetic flux is guided to the first rotor 20 through the second rotor 10 with almost no problem. Compared with FIGS. 3 and 5, it can be seen that the q-axis magnetic flux is guided from the stator 3 to the first rotor 20 without being substantially affected by the relative positions of the rotors 10 and 20.

  As described above with reference to FIGS. 2 to 7, the rotating electrical machine 2 that can change the magnetic flux of the permanent magnet 24 of the rotor 4 that is linked to the coil 3 b with a structure that can fully utilize the reluctance torque. Is realized.

[Arrangement structure of magnetic pole gap]
As described above, the phase (FIGS. 4 and 5) in which the relative positions of the two rotors deviate from the reference position by 90 degrees in electrical angle is the phase that can most reduce the field flux of the permanent magnet 24 interlinked with the coil 3b. It is. However, as is clear from comparison with FIG. 2 and FIG. 4, in the phase where the relative positions of the rotors 10 and 20 are shifted by 90 degrees in electrical angle, the bridge magnetic path 8 is in the radial direction of the magnetic pole in the alternate long and short dash line B. It becomes a magnetic path. Therefore, in this phase, the magnetic flux of the permanent magnet 24 passing through the bridge magnetic path 8 reaches the stator 3 as an interlinkage magnetic flux. Therefore, as shown in FIG. 4, the rotor core 21 of the first rotor 20 has the bridge magnet of the second rotor 10 in a state where the relative positions of the rotors 10 and 20 are in a phase shifted by 90 degrees in electrical angle from the reference position. A magnetic pole gap 9 is provided at a position facing the path 8 and serves as a magnetic resistance with respect to the field magnetic flux (d-axis magnetic flux). As shown in FIG. 4, the magnetic pole gap 9 serves as a flux barrier against the d-axis magnetic flux, and the field magnetic flux passing through the bridge magnetic path 8 is reduced. As a result, the field magnetic flux linked to the coil 3b can be reduced. According to the magnetic field analysis simulation results by the inventors, the magnetic flux density of the d-axis magnetic flux in the vicinity of the center of the tooth 34 is reduced by about 36% when the relative position of both rotors is deviated by 90 degrees in electrical angle from the reference position. It was.

  When the relative positions of the rotors 10 and 20 are deviated by 90 degrees from the reference position, the field magnetic field (d-axis magnetic flux) is the weakest field state. Therefore, in this state, the coil 3b is linked. I want to reduce as much as possible the field flux. In this embodiment, at this time, in the gap 7 between the magnetic poles that can also suppress the d-axis magnetic flux in the radial direction, the d-axis magnetic flux is radiated in the radial direction between the rotor 4 side and the stator 3 side. Since it is provided like a bridge that passes through R, the d-axis magnetic flux suppressing effect is reduced. However, by forming the magnetic pole gap 9 that can suppress the d-axis magnetic flux, the influence due to the provision of the bridge magnetic path 8 can be well eliminated.

[Cross-axis cross section of gap between magnetic poles, bridge magnetic path, magnetic pole gap]
The first rotor core 21 of the first rotor 20 has a structure in which the magnetic flux of the permanent magnet 24 and the magnetic flux generated by the coil 3b pass well, and the relative positions of the rotors 10 and 20 are deviated from the reference position by 90 degrees in electrical angle. In a state where the phase is in a different phase, it is desirable that the structure prevent the magnetic flux of the permanent magnet 24 passing through the bridge magnetic path 8. Therefore, the magnetic pole gap 9 is preferably formed in a shape that allows the first rotor core 21 to satisfy such a structure. For example, when the magnetic pole gap 9 is formed in a shape similar to the shape of the region sandwiched between the permanent magnets 24 adjacent in the circumferential direction in the axial orthogonal cross section, the portion of the first rotor core 21 serving as a magnetic path The portion that becomes the flux barrier is formed in a well-balanced manner. As shown in FIG. 2 to FIG. 7, in this embodiment, the shape of the region sandwiched between two permanent magnets 24 (permanent magnets 24 in the same magnetic pole direction) constituting the same pole adjacent in the circumferential direction in the axial orthogonal cross section. Is fan-shaped. And the magnetic pole space | gap 9 has a central angle substantially the same as the central angle of this sector shape in the center part of the circumferential direction of this sector shape, is a sector shape with a short radius, and is arrange | positioned with sufficient balance so that a mutual arc may overlap. .

  In the present embodiment, as shown in the enlarged view of FIG. 8, the magnetic flux changing region 70 including the bridge magnetic path 8 and the pair of magnetic pole gaps 7 (7 a, 7 b) and the bridge magnetic path 8 include the second rotor 10. The ratio of the arc on the side where the stator 3 is opposed to the circumference of the arc is larger than the ratio of the arc on the side where the first rotor 20 and the second rotor 10 are opposed. Since the circumferential surface facing the teeth 34 on the stator 3 side can be made wider, it is generated by the current flowing through the coil 3b in a state where the relative position is at the reference position, and the first rotor 20 and the second rotor 10 The magnetic flux circulating around the rotor cores 21 and 11 can be favorably guided.

  Further, similarly to the magnetic pole gap 9, it is preferable that a portion that becomes a magnetic path (bridge magnetic path 8) and a portion that becomes a magnetic flux barrier (interpole gaps 7 a and 7 b) are formed in a balanced manner in the magnetic flux change region 70. . For example, when the magnetic flux change region 70 and the bridge magnetic path 8 are similar, a well-balanced shape is obtained. Here, as described above, when the circumferential surface facing the teeth 34 on the side of the stator 3 is widened, it is naturally not a completely similar shape but a substantially similar shape. For example, when the gap 7 between the magnetic poles 7 is divided and formed by the bridge magnetic path 8 in the magnetic flux change area 70, the gaps 7 a and 7 b between the magnetic poles formed at both ends in the circumferential direction of the magnetic flux change area 70 are It is formed in a parallelogram shape in the orthogonal cross section. In this way, the magnetic resistance becomes uniform at any position in the radial direction, particularly with respect to the leakage magnetic flux that tries to pass through the circumferential direction of the second rotor 10. Moreover, the part used as a magnetic path in the magnetic flux change area | region 70 and the part used as a magnetic flux barrier are formed with sufficient balance.

  As described above with reference to FIGS. 2 to 8, the coil includes the inter-magnetic-pole gap 7, the bridge magnetic path 8, and the magnetic-pole gap 9 having an arrangement and a shape structure that can sufficiently utilize the reluctance torque. The rotating electrical machine 2 capable of changing the magnetic flux of the permanent magnet 24 of the rotor 4 interlinking with 3b is realized. In FIG. 9, the gap 7 between the magnetic poles is formed in the entire magnetic flux changing region 70 without the bridge magnetic path 8, and the gap 7 between the poles is naturally not provided. 6 is a graph comparing the magnitude of reluctance torque by magnetic field analysis in the case where the bridge magnetic path 8 and the magnetic pole gap 9 are provided. As is clear from FIG. 9, the reluctance torque is improved to about twice. Thereby, the efficiency of the rotary electric machine 2 in the case of outputting the same torque is also improved. FIG. 10 is a graph comparing the copper loss. As is apparent from this graph, the copper loss is reduced by 4%.

[Other Embodiments]
(1) In the above embodiment, the configuration in which the magnetic pole gap 9 is provided in the first rotor 20 is illustrated, but the magnetic pole gap 9 is not provided, and the interpole gap 7 and the bridge magnetic path 8 are provided only in the second rotor 10. It is good also as a structure to be made. As described above, by providing the inter-pole gap 7 and the bridge magnetic path 8 in the second rotor 10, the reluctance torque can be fully utilized regardless of the relative positions of the rotors 10 and 20. A rotating electrical machine that can change the field magnetic flux of the permanent magnet 24 interlinked with the coil 3b can be realized with the structure. More preferably, by providing the magnetic pole gap 9 in the first rotor 20, it is possible to suppress the field magnetic flux passing through the bridge magnetic path 8 in the phase where the field magnetic flux can be reduced most and enhance the field magnetic flux reduction effect. . However, when such a further reduction effect is not required, the magnetic pole gap 9 is not provided in the first rotor 20, and the interpole gap 7 and the bridge magnetic path 8 are provided only in the second rotor 10. Good.

(2) In the said embodiment, the case where the shape of the magnetic pole space | gap 9 in an axial orthogonal cross section was a shape similar to the shape of the area | region pinched | interposed into the permanent magnet 24 adjacent to the circumferential direction was illustrated. However, it is not limited to such a similar shape. That is, in a phase shifted by 90 degrees in electrical angle from the reference position, the shape can be configured in other shapes as long as it can be continuously configured as a flux barrier with a certain area in the circumferential direction together with the gap 7 between the magnetic poles as viewed in the radial direction R. There may be. Specifically, it may be a rectangle, a trapezoid in which the upper and lower bases are curved to the same degree as the curvature of the first rotor 20, or a band-like (arc-band) shape along the outer periphery of the first rotor 20. .

(3) In the above embodiment, as shown in FIG. 8, the magnetic flux changing region 70 and the bridge magnetic path 8 have a ratio with respect to the circumference of the arc on the side where the second rotor 10 and the stator 3 face each other. The case where 1 rotor 20 and the 2nd rotor 10 were formed so that it might become larger than the ratio with respect to the circumference of the arc in the side which opposes was illustrated. However, without being limited to such a configuration, the magnetic flux changing region 70 and the bridge magnetic path 8 may be formed so that the end portions in the circumferential direction are along radiation extending from the axis. In this case, the ratio of the arc to the circumference is almost the same as in the above embodiment. Further, contrary to the above embodiment, the magnetic flux changing region 70 and the bridge magnetic path 8 have a ratio with respect to the circumference of the arc on the side where the first rotor 20 and the second rotor 10 face each other. 3 may be formed so as to be larger than the ratio of the arc to the circumference on the opposite side. The magnetic flux changing region 70 and the circumferential ends of the bridge magnetic path 8 are along a line parallel to the line passing through the central portion of the magnetic flux changing region 70 along the radial direction of the rotor 4. When 70 and the bridge magnetic path 8 are formed, the ratio of the arc to the circumference is opposite to that in the above embodiment. Such a shape may be adopted depending on the ease of manufacture, low cost, etc., but such a shape naturally belongs to the technical scope of the present invention.

(4) In the said embodiment, the structure by which the permanent magnet 24 was provided only in the 1st rotor core 21 was demonstrated as an example. However, the embodiment of the present invention is not limited to this. For example, permanent magnets may be provided on both the first rotor core 21 and the second rotor core 11. Alternatively, only the second rotor core 11 may be provided with a permanent magnet, and a gap may be formed in the first rotor core 21.

(5) In the above embodiment, the inner rotor type rotating electrical machine has been described as an example. However, the present invention can naturally be applied to an outer rotor type rotating electrical machine. Regarding other configurations as well, the embodiments disclosed herein are illustrative in all respects, and the embodiments of the present invention are not limited thereto. That is, the present invention and a configuration equivalent to the present invention are provided, and a configuration in which a part of the above embodiment is appropriately modified belongs to the technical scope of the present invention without departing from the gist of the invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for a variable magnetic flux type rotating electrical machine that can adjust a field flux by a permanent magnet.

2: rotating electrical machine 3: stator 3a: coil (stator coil)
7, 7a, 7b: Gap between magnetic poles 8: Bridge magnetic path 9: Magnetic pole gap 10: Second rotor 11: Second rotor core (rotor core of the second rotor)
20: First rotor 21: First rotor core (rotor core of the first rotor)
24, 24N, 24S: Permanent magnet

Claims (5)

A rotating electrical machine comprising a stator having a stator coil, and a first rotor and a second rotor capable of adjusting a relative position in the circumferential direction,
The first rotor includes a rotor core and a permanent magnet that is embedded in the rotor core and provides a magnetic field flux interlinked with the stator coil.
The second rotor includes a rotor core and is disposed between the stator and the first rotor,
The rotor core of the second rotor includes a gap between magnetic poles that becomes a magnetic resistance with respect to the field magnetic flux,
The gap between the magnetic poles is a bridge magnetic path disposed at a position adjacent to the central portion between the magnetic poles of the permanent magnets adjacent in the circumferential direction and having different magnetic pole directions in a state where the relative positions of the two rotors are at the reference position. The rotating electric machine is divided into at least two parts.   The rotor core of the first rotor is disposed at a position facing the bridge magnetic path in a state where the relative position of both rotors is in a phase shifted by 90 degrees in electrical angle from the reference position. The rotating electrical machine according to claim 1, further comprising a magnetic pole gap serving as a magnetic resistance.   3. The rotating electrical machine according to claim 2, wherein the magnetic pole gap is formed in a shape similar to a shape of a region sandwiched between the permanent magnets in the same magnetic pole direction adjacent in the circumferential direction in an axial orthogonal cross section.   The magnetic flux changing region including the bridge magnetic path and the pair of gaps between the magnetic poles and the bridge magnetic path have a ratio with respect to the circumference of the arc on the side where the second rotor and the stator face each other. The rotating electrical machine according to any one of claims 1 to 3, wherein the rotating electrical machine is formed to be larger than a ratio of an arc to a circumference on a side facing the second rotor. 5. The rotating electrical machine according to claim 4, wherein the gaps between the magnetic poles divided by the bridge magnetic path are formed in a parallelogram shape in an axial orthogonal cross section.

Images