JP2014100048A - Permanent magnet type rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine which reduces cost and improves reliability while maintaining high torque and high output by suppressing magnetic flux leakage and demagnetization of permanent magnets.SOLUTION: A permanent magnet type rotary electric machine comprises: a stator 12 including a stator core 16; and a rotor 14 including a rotor core 24, a plurality of magnet embedding holes 32a, 32b formed in the rotor core and a plurality of permanent magnets 26a, 26b disposed in a radial direction of the rotor core. The magnet embedding hole has a center on a magnetic pole central axis of the rotor and is formed arcuate to protrude to a central side of the rotor. In the inner circumferential side magnet embedding hole, the rotor core includes two inner circumferential side support protrusions 34 which protrude into the magnet embedding hole in both end portions away from the magnetic pole central axis, and a center lock structure part 50 provided in the inner circumferential side magnet embedding hole on the magnetic pole central axis. The two permanent magnets embedded at both sides of the center lock structure part are held by engaging both end portions in an arcuate direction to the center lock structure part and one support protrusion.

Description

  Embodiments described herein relate generally to a permanent magnet type rotating electrical machine in which a permanent magnet is embedded in a rotor.

  In recent years, in-vehicle rotating electrical machines such as those for electric vehicles and hybrid vehicles have been strongly demanded to be highly efficient in order to suppress exhaust gas and improve fuel efficiency. Along with this, miniaturization and high output of rotating electrical machines using permanent magnets are being promoted.

  In-vehicle rotating electrical machines are required to have high torque and high output in a limited mounting space. Therefore, for example, a permanent magnet type reluctance type permanent magnet having a high magnetic energy product such as a rare earth (NdFeB) magnet arranged in a V shape and a cavity (a gap portion between magnetic poles) arranged on the outer peripheral side of the permanent magnet. A rotating electrical machine has been proposed. According to this rotating electrical machine, reluctance torque increases, and high output and variable speed operation are possible by obtaining high torque.

  On the other hand, in a permanent magnet type rotary electric machine used as an on-vehicle rotating electric machine, a rare earth magnet (NdFeB) having a strong magnetic force and a high energy product is often used. This rare earth magnet can generate a higher torque with a small volume. However, since rare earth metals are unevenly distributed and the amount of resources is scarce, there is a problem with the availability of the materials and the future resource depletion.

  Therefore, a rotating electrical machine using an inexpensive ferrite magnet, which has abundant resources, has been studied. However, ferrite magnets have a magnetic force as low as about 1/3 compared to rare earth magnets. Therefore, a permanent magnet type reluctance type rotating electrical machine that increases the generated torque by utilizing a reluctance torque by providing a slit with a multilayer structure in the rotor and arranging a permanent magnet in the slit, and combining it with the magnet torque by the permanent magnet. Has been proposed.

  In addition, in a rotating electrical machine for in-vehicle use, when it is rotated at a high speed in order to reduce the size, the stress due to the centrifugal force of the rotor core increases, which causes a problem. In view of this, a permanent magnet type rotating electrical machine has been proposed in which the permanent magnet embedded in the rotor core is held by protrusions to reduce the rotational centrifugal force of the permanent magnet and reduce the stress generated in the rotor core. ing.

  By providing the permanent magnet type reluctance type rotary electric machine using the ferrite magnet described above with the permanent magnet holding projection, a permanent magnet type reluctance type rotary electric machine capable of high speed rotation while using a ferrite magnet having a low magnetic force can be obtained.

JP-A-11-27913 Japanese Patent Laid-Open No. 2002-199675 JP 2011-83066 A JP 2001-339919 A Japanese Patent Application No. 2012-232125

  However, in the permanent magnet type reluctance type rotating electrical machine, it is difficult to sufficiently hold the outer peripheral side upper layer magnet by the magnet holding projection due to the deformation due to the rotational centrifugal force. In addition, the contact between the rotor core embedded hole and the magnet occurs, causing cracks and chipping of the magnet, and further, due to the deterioration of motor characteristics, increase in rotor core stress due to magnet cracking and chipping, and increase in rotational unbalance, The rotor may be damaged.

  The present invention has been made in view of the above points, and its problem is to avoid the damage of the permanent magnet and the destruction of the rotor, while maintaining high torque and high output, enabling high-speed rotation, low cost, Another object of the present invention is to provide a highly reliable permanent magnet reluctance type rotating electrical machine.

  According to the embodiment, a permanent magnet type rotating electrical machine includes a stator having a stator core and an armature winding attached to the stator core, and a rotor provided rotatably with respect to the stator. An iron core, a plurality of magnet embedding holes formed in a plurality of layers in the radial direction of the rotor core, and a plurality of magnets embedded in the magnet embedding hole and arranged in a plurality of layers in the radial direction of the rotor core A rotor including a permanent magnet. The plurality of magnet embedding holes include an outer peripheral magnet embedding hole located on the outer peripheral side of the rotor core, and an inner peripheral magnet embedding hole located on the center side of the rotor core, and the outer circumference The magnet embedding holes on the side and the inner circumference side are formed in an arc shape having a center on the magnetic pole central axis of the rotor and projecting toward the center side of the rotor, and the magnet embedding holes on the inner circumference side are The outer peripheral surface located on the outer peripheral side of the rotor core and the inner peripheral surface located on the center side of the rotor core and opposed to the outer peripheral surface with a space therebetween. The rotor core includes two inner peripheral support projections projecting from the inner peripheral surface into the magnet embedding hole at both ends away from the magnetic pole central axis in the inner magnet embedding hole, and the magnetic pole center. A center locking structure portion provided on the inner peripheral side magnet embedding hole on the shaft, and the plurality of permanent magnets in the inner periphery side magnet embedding hole of the center locking structure portion. Including two permanent magnets embedded on both sides, the two permanent magnets having an arcuate cross-sectional shape that is symmetrical to the left and right lines, and both ends in the arc direction are formed on the center locking structure part and one support protrusion It is engaged and held in the magnet embedding hole on the inner peripheral side.

FIG. 1 is a cross-sectional view illustrating a permanent magnet type rotating electrical machine according to a first embodiment. FIG. 2 is an enlarged cross-sectional view showing a part of the rotor of the rotating electrical machine. FIG. 3 is a cross-sectional view showing a permanent magnet type rotating electrical machine according to a second embodiment. FIG. 4 is an enlarged cross-sectional view illustrating a part of a rotor of a permanent magnet type rotating electrical machine according to a second embodiment. FIG. 5 is a cross-sectional view showing a permanent magnet type rotating electrical machine according to a third embodiment. FIG. 6 is an enlarged cross-sectional view showing a part of a stator and a rotor of a permanent magnet type rotating electric machine according to a third embodiment. FIG. 7 is an enlarged cross-sectional view of a part of a stator and a rotor of a permanent magnet type rotating electrical machine according to a fourth embodiment.

  Various embodiments will be described below with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. In addition, each drawing is a schematic diagram for promoting the embodiment and its understanding, and its shape, dimensions, ratio, etc. are different from the actual device, but these are considered in consideration of the following description and known techniques. The design can be changed as appropriate.

(First embodiment)
FIG. 1 is a cross-sectional view of a stator and a rotor of a permanent magnet type reactance type electric rotating machine 10 according to the first embodiment, and FIG. 2 is an enlarged cross-sectional view of the rotor.
In this embodiment, an 8-pole, 48-slot permanent magnet reluctance type rotating electrical machine will be described. However, the number of poles and the number of slots of the rotating electrical machine can be appropriately increased or decreased. As shown in FIG. 1, the rotating electrical machine 10 is configured as, for example, an inner rotor type rotating electrical machine, and has an annular, here, cylindrical stator 12 supported by a fixed frame (not shown), and an inner side of the stator. And a rotor 14 supported rotatably and coaxially with the stator.

  The stator 12 includes a cylindrical stator core 16 and an armature winding 18 embedded in the stator core. The stator core 16 is configured by laminating a large number of magnetic materials, for example, annular electromagnetic steel plates, in a concentric shape. A plurality of slots 20 extending in the axial direction are formed in the inner peripheral portion of the stator core 16, whereby the inner peripheral portion of the stator core 16 has a large number of stator teeth 21 facing the rotor 14. Is configured. The number of slots is composed of 48 slots. The armature windings 18 are embedded in these slots 20.

  The rotor 14 has a rotary shaft 22 that is rotatably supported by bearings (not shown) at both ends, a cylindrical rotor core 24 that is fixed at a substantially central portion in the axial direction of the rotary shaft, and embedded in the rotor core. A plurality of permanent magnets 26, and are arranged coaxially with a slight gap (air gap) inside the stator 12.

  The rotor core 24 is configured as a laminated body in which a large number of magnetic materials, for example, annular electromagnetic steel plates 24a, are laminated concentrically. The rotor core 24 has an easy magnetization axis (portion where magnetic flux easily passes) d and a hard magnetization axis (portion where magnetic flux does not easily pass) q extending in the radial direction or radial direction of the rotor core, respectively. The q axis and the q axis are formed alternately in the circumferential direction of the rotor core 24 and at a predetermined phase.

  A plurality of recesses 30 are formed in the outer peripheral portion of the rotor core 24. Each of the recesses 30 extends through the rotor core 24 in the axial direction and is located on the d-axis. The rotor core 24 includes a plurality of magnet embedded holes and a plurality of permanent magnets 26 embedded in these magnet embedded holes in order to form magnetic irregularities on the outer peripheral surface. For example, a ferrite magnet is used as the permanent magnet 26.

  As shown in FIGS. 1 and 2, the plurality of magnet embedding holes are formed side by side in a plurality of layers, for example, two layers, in the radial direction of the rotor core on each d-axis of the rotor core 24. The magnet embedding hole 32a on the outer peripheral side of the rotor core 24 has a circular cross section and extends through the rotor core 24 in the axial direction. Similarly, the magnet embedding hole 32b on the inner peripheral side of the rotor core 24 has a cross section formed in an arc shape and extends through the rotor core 24 in the axial direction.

  The two layers of the magnet embedding holes 32a and 32b are formed in an arc shape having a center on the d-axis (magnetic pole central axis) of the rotor core 24 and protruding toward the center side of the rotor core. Both end portions of the magnet embedding holes 32 a and 32 b extend to the vicinity of the outer peripheral surface of the rotor core 24. The rotor core 24 integrally has support protrusions 34 protruding from the inner peripheral side surfaces of the embedded holes into the embedded holes at both ends of the magnet embedded holes 32a and 32b in the arc direction.

  The plurality of permanent magnets 26 are inserted into the magnet embedding holes 32 a and 32 b and embedded in the rotor core 24. Each permanent magnet 26 is formed, for example, in the shape of an elongated bar having a circular arc cross section, and has a length substantially equal to the axial length of the rotor core 24. Each permanent magnet 26 is embedded over substantially the entire length of the rotor core 24. Thereby, the plurality of permanent magnets 26 are arranged in a plurality of layers, for example, two layers in the radial direction of the rotor core on each d-axis of the rotor core 24.

  That is, the permanent magnet 26 includes an outer permanent magnet 26a inserted into the outer magnet embedded hole 32a and an inner permanent magnet 26b inserted into the inner magnet embedded hole 32b. . The outer permanent magnet 26a is formed in an arcuate cross-sectional shape corresponding to the cross-sectional shape of the magnet embedding hole 32a, is fitted into the magnet embedding hole 32a, and is fixed to the rotor core 24 with an adhesive or the like. Further, the end faces of the permanent magnet 26a in the arc direction are in contact with the support protrusions 34, respectively, and the position in the arc direction is determined.

  The inner permanent magnet 26b has an arcuate cross-sectional shape corresponding to the cross-sectional shape of the magnet embedding hole 32b, is fitted into the magnet embedding hole 32b, and is fixed to the rotor core 24 with an adhesive or the like. Further, both end surfaces of the permanent magnet 26b in the arc direction are in contact with the support protrusions 34, and the position in the arc direction is determined. Thus, the two layers of permanent magnets 26a and 26b are arranged in a circular arc shape having a center on the d-axis (magnetic pole central axis) of the rotor core 24 and protruding toward the center side of the rotor core. .

  The magnet-embedded hole 32b on the inner peripheral side is an arc-shaped outer peripheral surface 33a located on the outer peripheral side of the rotor core 24, and an arc-shaped outer surface 33a located on the center side of the rotor core 24 and facing the outer peripheral surface 33a with a space therebetween. Of the inner peripheral surface 33b. The rotor core 24 includes two support projections 34 projecting from the inner circumferential surface 33b into the magnet embedding hole 32b at both ends in the arc direction away from the magnetic pole center axis d in the inner magnet embedding hole 32b, and the magnetic pole center. A center locking protrusion 50 that protrudes from the inner peripheral surface 33b into the magnet embedding hole 32b on the axis d is integrally provided. The center locking projection 50 constitutes a center locking structure provided at the center of the inner magnet embedded hole 32b.

  In the present embodiment, at least one of the two permanent magnets 26a and 26b arranged in multiple layers, for example, the inner permanent magnet 26b is divided into two permanent magnets 26b1 and 26b2 at the center thereof. The permanent magnets 26b1 and 26b2 are inserted and fixed in the magnet embedding holes 32b, respectively, and are embedded on both sides of the center locking projection 50. The two permanent magnets 26b1 and 26b2 are symmetrical with respect to the left and right lines and have an arcuate cross-sectional shape. Each permanent magnet 26b1, 26b2 has an end on the outer peripheral side in contact with the support protrusion 34 and an end on the magnetic pole central axis d side in contact with the center locking protrusion 50. Thus, the permanent magnets 26b1 and 26b2 are positioned and held in the magnet embedding holes 32b, respectively.

  As shown in FIG. 2, in the two layers of permanent magnets 26a and 26b positioned on each d-axis, at least the end of the magnet in the arc direction contacting the support protrusion 34 has a magnetization direction of d-axis (magnetic pole central axis). ) It is magnetized to face the side. In the present embodiment, the outer peripheral side permanent magnet 26a is magnetized so that the entire magnetization direction faces the magnetic pole central axis d side. Further, in the inner peripheral side permanent magnets 26b1 and 26b2, the end portion on the center locking projection 50 side is oriented so that the magnetization direction is directed to the q axis (central axis between magnetic poles), that is, the direction away from the d axis. It is magnetized. By arranging the plurality of permanent magnets 26a, 26b as described above, the regions on each d-axis form the magnetic pole portion 40 in the outer peripheral portion of the rotor core 24, and the regions on each q-axis form the inter-magnetic pole portion 42. Is forming. The rotor 14 generates a rotating magnetic field by causing a current to flow through the armature winding 18 attached to the rotor core 24, and the rotor 14 rotates due to the interaction between the rotating magnetic field and the generated magnetic field from the permanent magnet 26. The child 14 rotates about the rotation shaft 22.

In the present embodiment, the support protrusions 34 of the rotor core 24 are subjected to mechanical pressure by, for example, laser peening, shot peening, pressing, or the like, so that the saturation magnetic flux density is lower than other portions of the rotor core. As a result, the magnetic properties are deteriorated.
(Function)
Next, the operation of the rotating electrical machine 10 configured as described above will be described. When the rotating electrical machine 10 is operated, the centrifugal force that the permanent magnets 26a and 26b try to jump out in the radial direction is applied to the permanent magnets 26a and 26b by the rotation of the rotor 14. At this time, both end portions of the permanent magnets 26 a and 26 b in the arc direction are in contact with the support protrusions 34 of the rotor core 24, so that the permanent magnets 26 a and 26 b are centered by the support protrusions 34 and the center locking protrusions 50. 26b is held without jumping out.

  When the inner peripheral permanent magnet 26b is divided into two permanent magnets 26b1 and 26b2, the centrifugal force acting on the permanent magnet 26b on the magnetic pole central axis is reduced, and the displacement and deformation of the permanent magnets 26b1 and 26b2 are reduced. Is possible.

  Moreover, when it divides | segments into two permanent magnets 26b1 and 26b2, the gravity center position of each permanent magnet changes in the direction away from a magnetic pole center. In this case, the permanent magnets 26b1 and 26b2 are restrained by the support protrusions 34 provided at both ends in the arc direction of the magnet embedding hole. Therefore, as shown in FIG. A rotational moment M acts on the magnet. For this reason, the permanent magnets 26b1 and 26b2 hit the outer peripheral surface 33a of the magnet embedding hole 32b, and the stress acting on the rotor core 24 increases. According to the present embodiment, the center locking projection 50 is disposed as a center locking structure portion at the magnetic pole center, and the end portions of the permanent magnets 26b1 and 26b2 on the magnetic pole central axis side are in contact with the center locking projection 50. Thus, the rotation of the permanent magnets 26b1 and 26b2 can be suppressed. Thereby, it is possible to prevent the permanent magnets 26b1 and 26b2 from hitting the rotor core 24 at the outer peripheral surface 33a of the magnet embedding hole 32b, and to greatly reduce the stress acting on the rotor core 24. Therefore, deformation of the rotor core 24 due to centrifugal force can be suppressed, and the permanent magnets 26b1 and 26b2 can be stably held.

  Furthermore, since the center locking protrusion 50 is provided only on the inner peripheral surface side of the magnet embedding hole 32b, the leakage magnetic flux can be reduced. As a result, it is possible to suppress a decrease in torque and to obtain high torque and high output of the rotating electrical machine.

  When torque is generated, the leakage magnetic flux is less likely to flow because the magnetization direction of the permanent magnet is opposed to the leakage magnetic flux that tends to flow on the side surfaces of the end portions of the permanent magnets 26a and 26b. Further, in order to generate a large torque, when a large current is passed through the armature winding 18, the magnetization direction of the permanent magnet is opposite to the direction in which the armature reaction magnetic field that is the reverse magnetic field of the permanent magnets 26a and 26b is applied. Therefore, the magnetization of the permanent magnet is difficult to weaken.

(effect)
According to the first embodiment, since the rotational centrifugal force acting on the permanent magnets 26a and 26b is held by the support protrusion 34 and the center locking protrusion 50, the stress in the rotor core 24 can be reduced. High speed rotation and improved reliability can be achieved. Further, by suppressing the leakage magnetic flux from the side surfaces of the magnet end portions of the permanent magnets 26a and 26b, it is possible to suppress a decrease in torque and realize high torque and high output of the rotating electrical machine.

  By suppressing the decrease in magnetization of the permanent magnet due to the armature reaction, the permanent magnet becomes difficult to irreversibly demagnetize, and the reliability is improved. In addition, even when low-cost, low-magnetism ferrite magnets are used as permanent magnets, high-torque, high-output, high-speed rotation is possible, and a reliable, low-cost, permanent-magnet reluctance type rotating electrical machine is provided can do.

  Next, a rotating electrical machine according to another embodiment will be described. In other embodiments described below, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted, and the parts different from those in the first embodiment. Will be described in detail.

(Second Embodiment)
FIG. 3 is a cross-sectional view of the stator and the rotor of the permanent magnet type reactance rotating electrical machine 10 according to the second embodiment, and FIG. 4 is an enlarged cross-sectional view of a part of the stator and the rotor. .
In the present embodiment, as the center locking structure portion of the rotor core 24, a center bridge 58 provided at the center portion of the inner peripheral side embedded hole 32b and connecting the outer peripheral surface 33a and the inner peripheral surface 33b is used. . That is, as shown in FIG. 4 and FIG. 5, the outer peripheral magnet embedded hole 32a and the inner peripheral magnet embedded hole 32b are formed in two layers in the radial direction of the rotor core 24, and these magnet embedded Permanent magnets 26 a and 26 b are embedded in the holes 32 a and 32 b, and are arranged in two layers in the radial direction of the rotor core 24.

  The inner permanent magnet 26b is divided into two permanent magnets 26b1 and 26b2 at the center. The inner peripheral magnet embedding hole 32b for embedding the inner permanent magnet is also divided into two by a center bridge 48 provided on the central portion thereof, that is, on the magnetic pole central axis (d axis). The center bridge 48 is formed integrally with the rotor core 24.

  The permanent magnets 26b1 and 26b2 are respectively inserted and fixed in the magnet embedding holes 32b, and the respective magnet end portions located at both ends in the arc direction are in contact with the support protrusions 34 of the rotor core 24. The end portions of the permanent magnets 26b1 and 26b2 on the center bridge 48 side are in contact with the center bridge 48. Thus, the permanent magnets 26b1 and 26b2 are positioned and held in the magnet embedding holes 32b, respectively.

  In each permanent magnet 26b1, 26b2, the magnet end on the support projection 34 side is magnetized so that the magnetization direction faces the d-axis (magnetic pole central axis) side. In each permanent magnet 26b1, 26b2, the end on the center bridge 48 side is magnetized so that the magnetization direction is directed to the q axis (center axis between magnetic poles), that is, in a direction away from the d axis.

In the present embodiment, the support protrusions 34 of the rotor core 24 are subjected to mechanical pressure by, for example, laser peening, shot peening, pressing, or the like, so that the saturation magnetic flux density is lower than other portions of the rotor core. As a result, the magnetic properties are deteriorated.
In the third embodiment, other configurations of the rotating electrical machine are the same as those of the rotating electrical machine according to the first embodiment described above.

(Function and effect)
The operation and effect of the rotating electrical machine according to the second embodiment configured as described above will be described. When the inner peripheral permanent magnet 26b is divided into two permanent magnets 26b1 and 26b2, the centrifugal force acting on the permanent magnet 26b on the magnetic pole central axis is reduced, and the displacement and deformation of the permanent magnets 26b1 and 26b2 are reduced. Is possible.

  When the inner permanent magnet 26b is divided into two permanent magnets 26b1 and 26b2, the center of gravity of each permanent magnet changes in a direction away from the magnetic pole center. In this case, the permanent magnets 26b1 and 26b2 are restrained by the support protrusions 34 provided at both ends of the magnet embedding hole in the arc direction, so that the support protrusions 34 serve as fulcrums and act on the permanent magnets as shown in FIG. A rotational moment M acts on the permanent magnet by centrifugal force. For this reason, permanent magnet 26b1, 26b2 hits a rotor core, and the stress of a rotor core will increase. According to the present embodiment, the center bridge 48 is disposed as a center locking structure portion at the magnetic pole center portion, and the permanent magnets 26b1 and 26b2 come into contact with the stator core by suppressing the rotation of the permanent magnets 26b1 and 26b2. This can be prevented. As a result, the stress acting on the rotor core can be greatly reduced.

  Furthermore, the mechanical strength of the rotor core 24 is increased by connecting the outer peripheral portion and the inner peripheral portion of the center of the magnet embedding hole 32b by the center bridge 48 functioning as a center locking structure portion, and the rotation due to the rotational centrifugal force is increased. Deformation of the core is further suppressed. Thereby, the stress of the rotor core can be further reduced, the rotating electric machine can be rotated at high speed, and the reliability is improved with high output.

  Since the magnetization directions of the permanent magnets 26b1 and 26b2 are opposed to the leakage magnetic flux that tends to flow in the vicinity of the center bridge 48, the leakage magnetic flux hardly flows. As a result, it is possible to suppress a decrease in torque and to obtain high torque and high output of the rotating electrical machine.

  Further, in order to generate a large torque, when a large current is passed through the armature winding 18, the permanent magnet is applied to the direction in which the armature reaction magnetic field that is the reverse magnetic field of the permanent magnets 26b1 and 26b2 near the center bridge 48 is applied. Since the magnetization directions are opposed to each other, the magnetization of the permanent magnet is difficult to weaken. The permanent magnet is difficult to irreversibly demagnetize, and the reliability of the rotating electrical machine is improved.

  Further, by deteriorating the magnetic characteristics of the support protrusion 34 of the rotor core 24 as compared with other portions, it becomes difficult for the magnetic flux to flow through the support protrusion, and the leakage of the magnetic field can be more reliably reduced. Thereby, high torque and high output can be achieved.

(Third embodiment)
FIG. 5 is a cross-sectional view of the stator and the rotor of the permanent magnet reactance type rotating electrical machine 10 according to the third embodiment, and FIG. 6 is an enlarged cross-sectional view of the rotor.
As shown in FIGS. 5 and 6, the plurality of magnet embedding holes are formed side by side in a plurality of layers, for example, two layers in the radial direction of the rotor core on each d-axis of the rotor core 24. The magnet embedding hole 32a on the outer peripheral side of the rotor core 24 has a circular cross section and extends through the rotor core 24 in the axial direction. Similarly, the magnet embedding hole 32b on the inner peripheral side of the rotor core 24 has a cross section formed in an arc shape and extends through the rotor core 24 in the axial direction.

  The two layers of the magnet embedding holes 32a and 32b are formed in an arc shape having a center on the d-axis (magnetic pole central axis) of the rotor core 24 and protruding toward the center side of the rotor core. Both end portions of the magnet embedding holes 32 a and 32 b extend to the vicinity of the outer peripheral surface of the rotor core 24. The rotor core 24 integrally has support protrusions 34 protruding into the embedded hole from the inner peripheral side surface of the embedded hole at both ends in the arc direction of the magnet embedded holes 32a and 32b.

  The plurality of permanent magnets 26 are inserted into the magnet embedding holes 32 a and 32 b and embedded in the rotor core 24. Each permanent magnet 26 is formed, for example, in the shape of an elongated bar having a circular arc cross section, and has a length substantially equal to the axial length of the rotor core 24. Each permanent magnet 26 is embedded over substantially the entire length of the rotor core 24. Thereby, the plurality of permanent magnets 26 are arranged in a plurality of layers, for example, two layers in the radial direction of the rotor core on each d-axis of the rotor core 24.

  That is, the permanent magnet 26 includes an outer permanent magnet 26a inserted into the outer magnet embedded hole 32a and an inner permanent magnet 26b inserted into the inner magnet embedded hole 32b. . The outer permanent magnet 26a is formed in an arcuate cross-sectional shape corresponding to the cross-sectional shape of the magnet embedding hole 32a, is fitted into the magnet embedding hole 32a, and is fixed to the rotor core 24 with an adhesive or the like. Further, the end faces of the permanent magnet 26a in the arc direction are in contact with the support protrusions 34, respectively, and the position in the arc direction is determined.

  The inner permanent magnet 26b has an arcuate cross-sectional shape corresponding to the cross-sectional shape of the magnet embedding hole 32b, is fitted into the magnet embedding hole 32b, and is fixed to the rotor core 24 with an adhesive or the like. Further, both end surfaces of the permanent magnet 26b in the arc direction are in contact with the support protrusions 34, and the position in the arc direction is determined. Thus, the two layers of permanent magnets 26a and 26b are arranged in a circular arc shape having a center on the d-axis (magnetic pole central axis) of the rotor core 24 and protruding toward the center side of the rotor core. .

  In the two layers of permanent magnets 26a and 26b located on each d-axis, at least the arc ends of the magnets in contact with the support protrusions 34 are magnetized so that the magnetization direction faces the magnetic pole center axis d side. Yes. In the present embodiment, the permanent magnets 26a and 26b are magnetized so that the entire magnetization direction faces the magnetic pole central axis d side. By arranging the plurality of permanent magnets 26 as described above, the regions on each d-axis form the magnetic pole portions 40 in the outer peripheral portion of the rotor core 24, and the regions on each q-axis form the inter-magnetic pole portion 42. doing. The rotor 14 generates a rotating magnetic field by causing a current to flow through the armature winding 18 attached to the rotor core 24, and the rotor 14 rotates due to the interaction between the rotating magnetic field and the generated magnetic field from the permanent magnet 26. The child 14 rotates about the rotation shaft 22.

(Function)
Next, the operation of the rotating electrical machine 10 configured as described above will be described. When the rotating electrical machine 10 is operated, the centrifugal force that the permanent magnets 26a and 26b try to jump out in the radial direction is applied to the permanent magnets 26a and 26b by the rotation of the rotor 14. At this time, since both end portions of the permanent magnets 26a and 26b in the arc direction are in contact with the support protrusions 34 of the rotor core 24, the permanent magnets 26a and 26b are held by the support protrusions 34 without jumping out. Is done.

  When torque is generated, the leakage magnetic flux is less likely to flow because the magnetization direction of the permanent magnet is opposed to the leakage magnetic flux that tends to flow on the side surfaces of the end portions of the permanent magnets 26a and 26b. Further, in order to generate a large torque, when a large current is passed through the armature winding 18, the magnetization direction of the permanent magnet is opposite to the direction in which the armature reaction magnetic field that is the reverse magnetic field of the permanent magnets 26a and 26b is applied. Therefore, the magnetization of the permanent magnet is difficult to weaken.

  Further, the inner peripheral permanent magnet 26b is not divided into two, and the central portion in the arc direction extends substantially on the d-axis. Therefore, the permanent magnet 26b can generate a larger magnetic force and contribute to high torque and high output of the rotating electrical machine.

(effect)
According to the third embodiment, since the rotational centrifugal force acting on the permanent magnets 26a and 26b is held by the support protrusions 34, the stress in the rotor core 24 can be reduced, the rotating electrical machine can be rotated at high speed, and the reliability can be increased. It is possible to improve the performance. Further, by suppressing the leakage magnetic flux from the side surfaces of the magnet end portions of the permanent magnets 26a and 26b, it is possible to suppress a decrease in torque and realize high torque and high output of the rotating electrical machine.

  By suppressing the decrease in magnetization of the permanent magnet due to the armature reaction, the permanent magnet becomes difficult to irreversibly demagnetize, and the reliability is improved. In addition, even when low-cost, low-magnetism ferrite magnets are used as permanent magnets, high-torque, high-output, high-speed rotation is possible, and a reliable, low-cost, permanent-magnet reluctance type rotating electrical machine is provided can do.

(Fourth embodiment)
FIG. 7 is an enlarged cross-sectional view of a part of the rotor of the permanent magnet type rotating electric machine according to the fourth embodiment. According to the present embodiment, the nonmagnetic material, for example, the carbon reinforcing fiber 46 is disposed between the magnet end portions of the permanent magnets 26 a and 26 b and the support protrusion 34. The carbon reinforcing fiber 46 is fixed to the end surfaces (side surfaces) of the magnet end portions of the permanent magnets 26a and 26b, extends substantially over the entire length of the permanent magnets 26a and 26b, and is in contact with the support protrusion 34.
The other configuration of the rotating electrical machine is the same as that of the rotating electrical machine according to the third embodiment described above.

(Function)
By providing a nonmagnetic material between the end of the permanent magnet and the support protrusion 34 as described above, the magnetic resistance between the permanent magnets 26a and 26b and the support protrusion 34 is increased, and the leakage magnetic flux is difficult to flow. Also in the magnetic field due to the armature reaction that becomes a reverse magnetic field of the permanent magnets 26a and 26b, the magnetic resistance between the permanent magnet and the support protrusion 34 is increased, so that the magnetization of the permanent magnet is not easily weakened. Further, since the nonmagnetic material is a carbon reinforced fiber having high compressibility and low specific gravity, the centrifugal force due to rotation can be reduced, and the reliability of holding the permanent magnet is improved accordingly.

(effect)
According to the fourth embodiment, the leakage magnetic flux can be further suppressed by the non-magnetic material, the torque can be suppressed from decreasing, and high torque and high output can be achieved. Further, by suppressing the decrease in magnetization of the permanent magnet due to the armature reaction, the permanent magnet becomes difficult to irreversibly demagnetize, and the reliability is improved. The rotational centrifugal force of the nonmagnetic material is reduced, the stress of the rotor core can be reduced, and further high-speed rotation and reliability are improved.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, the permanent magnet type rotating electrical machine is not limited to the inner rotor type, and may be an outer rotor type. The number of magnetic poles, the size, the shape, and the like of the rotor are not limited to the above-described embodiments, and can be variously changed according to the design. Further, the multilayer arrangement of the permanent magnets 26 in the rotor core 24 is not limited to two layers, and may be three or more layers.

DESCRIPTION OF SYMBOLS 10 ... Rotary electric machine, 12 ... Stator, 14 ... Rotor, 16 ... Stator iron core,
18 ... Armature winding, 20 ... Slot, 22 ... Rotating shaft, 24 ... Rotor core,
26, 26a, 26b ... permanent magnets, 26b1, 26b2 ... permanent magnets,
32a, 32b ... magnet embedding hole, 34 ... support projection, 46 ... non-magnetic material,
48 ... Center bridge, 50 ... Center locking protrusion

Claims (12)

A stator having a stator core and an armature winding attached to the stator core;
A rotor core rotatably provided to the stator; a plurality of magnet embedded holes formed in a plurality of layers in a radial direction of the rotor core; and the rotor embedded in the magnet embedded holes. A rotor provided with a plurality of permanent magnets arranged in a plurality of layers in the radial direction of the iron core, and
The plurality of magnet embedding holes include an outer peripheral magnet embedding hole located on the outer peripheral side of the rotor core, and an inner peripheral magnet embedding hole located on the center side of the rotor core, and the outer circumference The side and inner peripheral magnet embedding holes are formed in an arc shape having a center on the magnetic pole central axis of the rotor and projecting toward the center side of the rotor,
The inner peripheral magnet embedding hole is formed by an outer peripheral surface located on the outer peripheral side of the rotor core, and an inner peripheral surface located on the center side of the rotor core and facing the outer peripheral surface with a gap therebetween. Prescribed,
The rotor core includes two inner peripheral support projections projecting from the inner peripheral surface into the magnet embedding hole at both end portions away from the magnetic pole central axis in the inner magnet embedding hole, and the magnetic pole A center locking structure provided in the inner circumferential magnet embedding hole on the central axis, and
The plurality of permanent magnets includes two permanent magnets embedded on both sides of the center locking structure portion in the inner peripheral side magnet embedding hole, and the two permanent magnets are symmetrical with respect to the left and right lines and are arc-shaped. A permanent magnet type rotating electrical machine having a cross-sectional shape and having both ends in an arc direction engaged with the center locking structure portion and one support projection and held in the inner magnet embedding hole.   2. The permanent magnet piece according to claim 1, wherein the center locking structure portion has a center locking protrusion that protrudes into the magnet embedding hole from an inner peripheral surface of the inner magnet embedding hole on the magnetic pole central axis. Rotating electric machine.   3. The permanent magnet type rotating electric machine according to claim 2, wherein ends of the two permanent magnets on the side of the center locking protrusion are magnetized so that a magnetization direction faces a side away from the magnetic pole central axis.   The center locking structure has a center bridge that connects an inner peripheral surface and an outer peripheral surface of the inner magnet embedded hole, and the two permanent magnets are on the inner peripheral side on both sides of the center bridge. The permanent magnet type rotating electrical machine according to claim 1, wherein the permanent magnet type rotating electrical machine is disposed in the magnet embedding hole.   5. The permanent magnet type rotating electric machine according to claim 4, wherein ends of the two permanent magnets on the center bridge side are magnetized so that a magnetization direction faces a side away from the magnetic pole central axis.   6. The rotor core according to claim 1, further comprising: two support protrusions that project into the magnet embedding hole on the outer peripheral side, abut against both ends of the permanent magnet in the arc direction, and support the permanent magnet. The permanent magnet type rotating electric machine according to item.   The permanent magnet type rotating electrical machine according to claim 6, wherein an end portion of the permanent magnet in contact with the support protrusion is magnetized so that a magnetization direction thereof faces the magnetic pole central axis.   The permanent magnet type rotating electric machine according to any one of claims 1 to 7, wherein the permanent magnet is magnetized so that a magnetization direction thereof is directed to the magnetic pole central axis.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 8, further comprising a nonmagnetic material disposed between an end portion of the permanent magnet and the support protrusion.   The permanent magnet type rotating electrical machine according to claim 9, wherein the nonmagnetic material is made of a carbon reinforcing fiber.   The permanent magnet type rotating electrical machine according to claim 1, wherein the support protrusion is processed to have a saturation magnetic flux density lower than that of other portions of the rotor core.   The permanent magnet type rotating electric machine according to any one of claims 1 to 11, wherein the permanent magnet is a ferrite magnet.

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