JP6385715B2 - Rotating electric machine - Google Patents

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 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. 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.

  Permanent magnet type reluctance type rotating electrical machines using the above-described ferrite magnets are provided with permanent magnet holding projections, so that a permanent magnet type reluctance type rotating electrical machine that can rotate at high speed while using a ferrite magnet with low magnetic force is provided. can get.

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, contact between the rotor core embedded hole and the magnet occurs, causing cracking and chipping of the magnet, and further rotor damage due to motor characteristics deterioration, rotor core stress increase, and rotation unbalance increase. there is a possibility.

  The present invention has been made in view of the above points, and the problem is that the permanent magnet can be securely held and the movement of the permanent magnet, breakage, and destruction of the rotor can be avoided, and high-speed rotation is possible. It is another object of the present invention to provide a highly reliable permanent magnet type rotating electrical machine.

According to the embodiment, the rotating electrical machine includes a stator including a stator core and an armature winding attached to the stator core, and a rotor core provided rotatably with respect to the stator. comprising a rotor, wherein the rotor core includes an inner circumferential side magnet containing hole capable of containing a central permanent magnet, the rotor core radially outward of the rotor core than the inner circumference side magnet containing hole circumferential and two divided permanent magnets capable of accommodating the outer circumferential side magnet containing holes, are formed, in the cross section perpendicular the rotor core with respect to the rotation center of the rotor core, the outer circumferential side magnets the rotation center side of the first edge defining the accommodating hole, wherein each of the second edge located at the radially outer side than the first edge, is formed in a curve is convex prior Symbol rotation center side In the cross section of the rotor core perpendicular to the center of rotation. The rotation center of the third edge defining the inner circumference side magnet containing hole, each of the fourth edge located at the radially outer side than the third edge, and a convex to the rotation center side The position of the split permanent magnet is defined by contacting the split permanent magnet at the portion of the second edge that is most convex on the rotation center side of the second edge, toward the first edge. The second edge that defines a position of the split permanent magnet by contacting the split permanent magnet in each of the vicinity of both end portions of the first edge. An inner peripheral side locking projection that protrudes toward the center, and the cross section of the magnet perpendicular to the rotation center is axisymmetric with respect to a straight line connecting the rotation center and the outer side central locking projection. Outer side center locking projection and near one end Between the serial inner side locking projection, and, wherein the divided permanent magnets are fixed respectively, that between the outer peripheral side central locking projection and the other end portion the inner circumferential side locking projection in the vicinity And

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 diagram showing a relationship between a ratio (bridge position) between a width of the inner peripheral side central permanent magnet and a width of the end side permanent magnet and a motor characteristic (torque). 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.

  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 reluctance type rotating electrical machine 10 according to the first embodiment, and FIG. 2 is an enlarged cross-sectional view of a part 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 16. 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. And a plurality of permanent magnets arranged coaxially with a small 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 magnetic steel sheets, are laminated concentrically. The rotor core 24 has an easy magnetization axis (part where magnetic flux easily passes) (d axis) and a hard axis (part where magnetic flux hardly passes) (q axis) extending in the radial direction or radial direction of the rotor core. The d-axis and the q-axis are alternately formed 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 embedded in the 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.

  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. A magnet embedding hole (outer periphery side magnet housing hole) 32 on the outer peripheral side of the rotor core 24 is formed in an arc shape in the cross section, and extends through the rotor core 24 in the axial direction.

  The axis of the rotor core 24 referred to here is the rotation center C of the rotor core 24. In other words, in the cross section perpendicular to the central axis of the rotor core 24, the first edge 51 on the rotation center C side that defines the magnet embedded hole 32 on the outer peripheral side is formed in a curve that is convex toward the rotation center C side. Has been. Further, in a cross section perpendicular to the rotation center C of the rotor core 24, a second position that is located on the outer side in the radial direction of the rotor core 24 relative to the first edge 51 that defines the magnet embedded hole 32 on the outer peripheral side. The edge 52 is formed in a curve that is convex toward the rotation center C side.

  Similarly, the magnet embedding hole 34 on the inner peripheral side of the rotor core 24, that is, on the central axis side of the rotor core 24, has a substantially circular cross section, and penetrates the rotor core 24 in the axial direction. It extends.

  Two layers of magnet embedding holes 32 and 34 on the outer peripheral side and the inner peripheral side have a center on the d-axis (magnetic pole central axis) of the rotor core 24 and project in the center side of the rotor core. Is formed. Both end portions of the magnet embedding holes 32 and 34 extend to the vicinity of the outer peripheral surface of the rotor core 24.

  The magnet-embedded hole 32 on the outer peripheral side is defined by an outer peripheral surface 32a located on the outer peripheral side of the rotor core 24 and an inner peripheral surface 32b facing the outer peripheral surface with a certain distance. The outer peripheral surface 32 a is a surface including the first edge 51. The inner peripheral surface 32 b is a surface including the second edge 52.

  In the present embodiment, the outer peripheral surface 32a and the inner peripheral surface 32b are formed in a concentric arc shape. Further, the rotor core 24 has two inner peripheral side locking projections that protrude into the embedded hole 32 from the inner peripheral surface 32b in the vicinity of both ends in the arc direction away from the magnetic pole central axis d of the magnet embedded hole 32 on the outer peripheral side. (Locking structure portion) 36a and one central locking protrusion (center locking protrusion) protruding from the outer peripheral surface 32a into the embedded hole 32 on the center in the arc direction of the magnet embedded hole 32, that is, on the magnetic pole central axis d. Structure part) 36b.

  In other words, in the cross section of the rotor core 24 perpendicular to the rotation center C, inner peripheral side locking projections 36 a are formed in the vicinity of both ends of the first edge 51. The outer peripheral side center locking projection 36b is formed in a portion that protrudes most toward the rotation center C of the second edge 52, and a portion that is most convex on the rotation center C side and the rotation center in the second edge 52. And the magnetic pole central axis d overlap.

  On the other hand, the inner magnet embedded 34 is divided into a plurality of embedded holes by a plurality of bridges. In the embodiment, the rotor core 24 has a plurality of, for example, two bridges 38 respectively connecting the outer peripheral portion and the inner peripheral portion of the magnet embedded hole 34 on the inner peripheral side. The two bridges 38 are provided on both sides of the magnetic pole center axis d and at equal intervals from the magnetic pole center axis d. As a result, the inner magnet embedded hole 34 has an arc-shaped central embedded hole (inner peripheral magnet receiving hole) 34a positioned on the magnetic pole central axis d, and two magnets positioned on both sides of the central embedded hole. It is divided into an end-side embedded hole (side magnet accommodation hole) 34b.

  More specifically, in the cross section perpendicular to the rotation center C of the rotor core 24, the third edge 53 on the rotation center C side that defines the central embedded hole 34a is convex toward the rotation center C side. It is formed in a curve. In addition, in the cross section perpendicular to the central axis of the rotor core 24, the fourth edge 54, which defines the central embedded hole 34a and is located on the radially outer side of the rotor core 24 relative to the third edge 53, has a rotation center. It is formed in a curve that is convex on the C side.

  In a cross section perpendicular to the rotation center C of the rotor core 24, the fifth edge 55 that defines the end-side embedded hole 34b is formed linearly along the extending direction of the third edge 53, The sixth edge 56 positioned on the rotation center C side with respect to the fifth edge 55 is formed in a straight line parallel to the fifth edge 55. In other words, the surface 91 on the rotation center C side that defines the end-side embedded hole 34b is a flat surface, and the surface 92 facing the flat surface 91 is a flat surface parallel to the surface 91. Surface 92 includes a fifth edge 55 and surface 91 includes a sixth edge 56.

  The rotor core 24 includes two locking protrusions (locking structure portions) 42a protruding from the inner peripheral surface into the central embedded hole 34a at both ends in the arc direction away from the magnetic pole central axis d of the central embedded hole 34a. An outer peripheral side end portion of each end side embedded hole 34b integrally has one outer peripheral side locking projection (locking structure portion) 42b protruding from the inner peripheral surface into the end side embedded hole.

  As shown in FIGS. 1 and 2, the plurality of permanent magnets includes a plurality of outer peripheral side permanent magnets embedded in the outer peripheral side magnet embedded hole 32 and a plurality of permanent magnets embedded in the inner peripheral side magnet embedded hole 34. And a permanent magnet on the inner peripheral side. Each permanent magnet has a length substantially equal to the axial length of the rotor core 24. Each permanent magnet is embedded over substantially the entire length along the rotation center C of the rotor core 24. Thereby, a plurality of permanent magnets are arranged side by side in the radial direction of the rotor core, for example, two layers, on each d-axis of the rotor core 24.

  More specifically, the outer peripheral permanent magnet embedded in the outer peripheral magnet embedding hole 32 includes two divided permanent magnets 26a and 26b embedded on both sides of the outer peripheral central locking projection 36b.

  Each of the divided permanent magnets 26a and 26b is symmetrical with respect to the left and right lines, has an arcuate cross-sectional shape, is fitted into the magnet embedding hole 32, and is fixed to the rotor core 24 with an adhesive or the like. Each of the divided permanent magnets 26a and 26b engages with the outer peripheral side central locking projection 36b and the inner peripheral side locking projection 36a at both ends in the arc direction, and is held in the magnet embedded hole 32 on the outer peripheral side. The two divided permanent magnets 26a and 26b have the same cross-sectional shape.

  That is, the split permanent magnet 26a is in surface contact with the outer peripheral surface (second surface) 61 that is in surface contact with the outer peripheral surface 32a of the outer magnet embedded hole 32 and the inner peripheral surface 32b of the outer magnet embedded hole 32. The inner peripheral surface (first surface) 62 and flat both end surfaces (third and fourth surfaces) 63, 64 are provided, the end surface 63 abuts on the outer peripheral side central locking projection 36b, and the end surface 64 is The position in the arc direction is determined by coming into contact with the inner peripheral side locking protrusion 36a in the vicinity of the one end.

  Similarly, the split permanent magnet 26b is in surface contact with the outer peripheral surface (second surface) 65 that is in surface contact with the outer peripheral surface 32a of the magnet embedded hole 32 on the outer peripheral side and the inner peripheral surface 32b of the magnet embedded hole 32 on the outer peripheral side. An inner peripheral surface (first surface) 66 and flat end surfaces (third and fourth surfaces) 67, 68. The end surface 67 abuts on the outer peripheral side central locking projection 36b, and the end surface 68 Are in contact with the inner peripheral side locking projections 36a in the vicinity of the other end, and the position in the arc direction is determined.

  The split permanent magnets 26a and 26b are fixed so that a cross section perpendicular to the rotation center C is line-symmetric with respect to a straight line connecting the rotation center C and the outer peripheral side center locking projection 36b.

  The plurality of permanent magnets on the inner peripheral side are symmetrical with the central permanent magnet 28a embedded in an inner peripheral central magnet embedding hole 34a located between the two bridges 38, for example, with a circular arc cross section. The left and right line symmetrical shapes embedded in the two end side magnet embedded holes 34b located on both sides of the central magnet embedded hole 34a, for example, two end side permanent magnets 28b having a quadrilateral cross section are included. These permanent magnets 28a and 28b are fitted into the magnet embedding hole 34 and fixed to the rotor core 24 with an adhesive or the like. Each inner peripheral side permanent magnet 28a, 28b has a cross-sectional shape that is symmetrical with respect to the left-right line. Further, the center permanent magnet 28a has both end surfaces in the arc direction abutting against the locking projections 42a, and the position in the arc direction is determined. Each end-side permanent magnet 28b has an outer peripheral end surface that abuts on the outer peripheral-side locking projection 42b, and a circumferential position is determined.

  In other words, the central permanent magnet 28a accommodated in the central embedded hole 34a has 81 in surface contact with the surface 71 of the central embedded hole 34a and 82 in surface contact with the surface 72 of the central embedded hole 34a. The surface 71 is a surface including the third edge 53. The surface 72 is a surface located on the radially outer side of the rotor core 24 with respect to the surface 71. The surface 72 is a surface including the fourth edge 54. The surfaces 71 and 81 are fixed to each other with an adhesive or the like. The surfaces 72 and 82 are fixed to each other with an adhesive or the like.

  The end-side permanent magnet 28b has a rectangular cross section perpendicular to the rotation center C. Specifically, the end-side permanent magnet 28b includes a seventh edge 57 facing the fifth edge 55 of the end-side embedded hole 34b and the end-side embedded hole 34b in a cross section perpendicular to the rotation center C. And an eighth edge 58 opposite to the sixth edge 56. The seventh edge 57 and the eighth edge 58 are formed in linear shapes parallel to each other. The surface 93 including the seventh edge 57 of the end permanent magnet 28b and the surface 94 including the eighth edge 58 of the end permanent magnet 28b are planes parallel to each other. The surfaces 91 and 93 are in surface contact with each other. The surfaces 92 and 94 are in surface contact with each other.

  In the cross section of the central permanent magnet 28a perpendicular to the rotation center C, the thickness L1 along the direction perpendicular to the third edge 53 is the fifth in the cross section of the end permanent magnet 28b perpendicular to the rotation center C. It is larger than the thickness L2 along the direction perpendicular to the edge 55.

  As a result, the two-layer permanent magnets on the outer peripheral side and the inner peripheral side have a center on the d-axis (magnetic pole central axis) of the rotor core 24 and have an arc shape that is convex toward the center side of the rotor core. Has been placed.

  The permanent magnets on the outer peripheral side and the inner peripheral side are magnetized so that the entire magnetization direction faces the magnetic pole central axis d side. By disposing a plurality of permanent magnets as described above, the regions on each d-axis form magnetic pole portions 40 in the outer peripheral portion of the rotor core 24, and the regions on each q-axis form magnetic pole portions 42. ing. The rotor 14 generates a rotating magnetic field by causing a current to flow through the armature winding 18 mounted on the rotor core 24, and the rotor 14 is caused by the interaction between the rotating magnetic field and the generated magnetic field from the permanent magnet. 14 rotates around 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 magnet is about to jump out in the radial direction acts on the permanent magnet due to the rotation of the rotor 14. At this time, the permanent magnet on the outer peripheral side is constituted by two divided permanent magnets 26a and 26b, and each of the divided permanent magnets 26a and 26b is symmetrical with respect to the left and right lines and is circularly arranged. In other words, each of the divided permanent magnets 26 a and 26 b is fixed to the rotor core 24 in an attitude that is inclined with respect to the radial direction of the rotor 14 due to the circular arc shape.

  The positions of the center of gravity of the divided permanent magnets 26a and 26b are not on the magnetic pole center axis d but on the side between the magnetic poles. In other words, the gravity center positions of the divided permanent magnets 26a and 26b are shifted to the inter-magnetic pole portion 42 side with respect to the magnetic pole central axis d. Each split permanent magnet 26a, 26b is in contact with the center locking projection 36b and one inner circumferential locking projection 36a, and the position in the arc direction is determined.

  As a result, even if the rotor core 24 is subjected to stress due to centrifugal force due to rotation and is distorted, the divided permanent magnets 26a and 26b are securely held by the locking projections 36a and 36b, and the magnets are moved, damaged, and the like. Is prevented. Since the central locking projection 36b is provided at the central portion of the outer peripheral surface, the movement of the permanent magnets and the like can be prevented without the two split permanent magnets 26a and 26b coming into contact with each other. Moreover, it is not necessary to arrange a bridge at the center of the magnetic pole, and the leakage magnetic flux is suppressed.

  Further, by forming a protrusion that receives a force to protrude outward along the inner peripheral surface 32b and the outer peripheral surface 32a on the first edge 51 as the inner peripheral locking protrusion 36a, the protrusion is likely to protrude outward. It is possible to improve the load resistance of the protrusions against the force of

  This point will be specifically described. Due to the centrifugal force acting on each divided permanent magnet 26a, 26b, each divided permanent magnet 26a, 26b tends to jump outward along the inner peripheral surface 32b and the outer peripheral surface 32a of the magnet embedding hole 32.

  In the cross section perpendicular to the rotation center C, the thickness between the second edge 52 and the outer peripheral surface of the rotor core 24 is relatively small, but there is sufficient thickness around the first edge 51. Can be secured. For this reason, by forming the inner peripheral side locking projection 36a on the first edge 51, a sufficient thickness to support the inner peripheral side locking projection 36a is secured around the inner peripheral side locking projection 36a. Therefore, the load that the inner peripheral side locking projection 36a can withstand, that is, the load resistance can be improved.

  The divided permanent magnet 26a tries to move away from the rotation center C along the inner peripheral surface of the magnet embedding hole 32, but the movement is suppressed by the inner peripheral side locking projection 36a, so that the inner peripheral side locking projection 36a and Rotation moment is generated in such a manner that the end face opposite to the contact is moved away from the rotation center C with the contact point of the rotation point as the rotation center. Due to this rotational moment, it tries to move in the direction in which the end faces facing each other of the adjacent divided permanent magnets come into contact.

  By forming a protrusion, which is a protrusion for preventing the divided permanent magnets 26a, 26b from moving in a direction in contact with each other, on the second edge 52 as an outer peripheral side central locking protrusion 36b, the divided permanent magnet 26a, The divided permanent magnets 26a and 26b can be enlarged while reliably preventing the 26 from coming into contact with each other.

  This point will be specifically described. The third surfaces 63 and 67 which are the portions facing each other in the divided permanent magnets 26a and 26b tend to be distorted in a direction approaching each other due to centrifugal force. Furthermore, in the third surfaces 63 and 67, a greater centrifugal force acts on the inner portion of the radially outer portion of the rotor 14. For this reason, in the 3rd surfaces 63 and 67, the part of the radial direction outer side of the rotor 14 exists in the tendency which is distorted more largely with respect to an inner side part.

  However, by receiving the radially outer portion of the rotor 14 on the third surfaces 63 and 67, which tends to be more distorted by forming the outer peripheral side central locking projection 36 b on the second edge 52, That is, by receiving the contact, it is possible to prevent the split permanent magnets 26a and 26b from being distorted in a direction approaching each other.

  For this reason, since it is not necessary to form the protrusion which prevents the division | segmentation permanent magnets 26a and 26b from mutually contacting in the 1st edge 51, the part of the division | segmentation permanent magnets 26a and 26b in the radial direction of the rotor 14 is provided. , They can be formed in shapes that approach each other. That is, the divided permanent magnets 26a and 26b can be enlarged.

  The inner peripheral side permanent magnet is divided into a central permanent magnet 28a located between the bridges 38 and two end side permanent magnets 28b located on both sides of the central permanent magnet. A flat magnet can be used in combination. In addition, by using a plurality of bridges 38, it is possible to apply a left-right symmetric permanent magnet, and the magnetic path shape of the rotor core equivalent to the conventional one can be obtained. Thereby, the high torque and the high output characteristic which utilized the reluctance torque are securable.

  By dividing the magnet arranged on the inner peripheral side into a plurality of parts, the center of gravity of the magnet can be arranged symmetrically with respect to the magnetic pole axis on the side of the magnetic pole axis, not on the magnetic pole axis. Moreover, the mass per magnet can be halved and the force generated by the centrifugal force can be reduced. Thereby, the force which acts on the latching protrusion 42a which receives the center permanent magnet 28a in the rotor core 24 can be made small. Similarly, the force acting on the locking projection 42b that receives the end permanent magnet 28b in the rotor core 24 can be reduced. For this reason, the retention strength with respect to the rotor core 24 of the end side permanent magnet 28b can be increased.

  A large centrifugal force acts on the end permanent magnet 28b with respect to the center permanent magnet 28a. However, by making the thickness L2 of the end side permanent magnet 28b smaller than the thickness L1 of the center permanent magnet 28a, the weight of the end side permanent magnet 28b can be reduced, so that the centrifugal force acting on the end side permanent magnet 28b is affected. The influence can be kept small.

  By providing a plurality of, for example two, bridges provided in the magnet embedding hole 34 on the inner peripheral side, the bridge width and bridge that maximize the motor characteristics (torque) while ensuring the thickness of the permanent magnet at the magnetic pole center portion. The position can be set. When the number of bridges is one, the width of the bridge can be reduced, but the amount of permanent magnets is reduced because the bridge needs to be arranged at the center of the magnetic pole where the thickness of the permanent magnet is large. That is, the motor torque is reduced. On the other hand, when two bridges are provided, bridges can be arranged on both sides of the magnetic pole central axis, and a permanent magnet can be arranged between the two bridges, that is, in the central part of the magnetic pole. Thereby, it becomes possible to secure the thickness of the permanent magnet at the magnetic pole central portion and increase the magnet amount. Therefore, the motor characteristics (torque) can be maximized by appropriately setting the bridge width.

  As shown in FIG. 3, when the length in the arc direction of the central permanent magnet 28a is Wc and the length in the longitudinal direction of each end-side permanent magnet 28b is Ws, FIG. 3 shows the ratio of the magnet length (Ws / Wc). That is, the relationship between the position where the two bridges 38 are disposed and the motor characteristics (torque) is shown. As shown in FIG. 3, when the ratio (Ws / Wc) between the length Wc of the central permanent magnet and the length Ws of the end permanent magnet changes, it can be seen that the motor characteristics change. Increasing the length Wc of the central permanent magnet 28a, that is, increasing the distance between the two bridges 38 increases the magnet area (magnet amount) and improves the torque characteristics. However, if the length ratio (Ws / Wc) exceeds a certain point (1.70), the stress acting on the permanent magnet due to the centrifugal force increases, so that the width of the bridge 38 needs to be widened to increase the strength. . As the bridge width increases, the leakage flux increases, so the torque characteristics of the motor decrease. In the present embodiment, the two bridges 38 are arranged so that the permanent magnet length ratio (Ws / Wc) is in the vicinity of 1.70. Therefore, it is not necessary to increase the width of each bridge 38, and optimal motor characteristics (torque) can be obtained.

  Regarding the bridge width, the iron core (electromagnetic steel plate) thickness is the limit as the minimum width in terms of manufacturing, and in order to make it within the allowable stress, it is necessary to increase the bridge width as the amount of magnet increases. Therefore, it is desirable to select the bridge width while maintaining the relationship between the center permanent magnet length and the end permanent magnet length, that is, the distance between the two bridges, the position of the bridge, and the optimum. By narrowing the bridge width, the leakage magnetic flux can be reduced and the torque characteristics can be improved. On the other hand, when the bridge width is narrowed, the stress acting on the rotor core (bridge portion stress) increases and may exceed the allowable stress of the bridge. Therefore, it is desirable to set a bridge width that is less than the allowable stress. From the above, the motor characteristics (torque) can be maximized by appropriately setting the bridge disposition position and the bridge width.

(effect)
According to the first embodiment, even if the rotor core and the permanent magnet are subjected to stress due to the centrifugal force due to the rotation and are distorted, the split permanent magnets are separated by the outer peripheral side central locking protrusion and the inner peripheral locking protrusion. It is possible to securely hold, prevent breakage such as cracking and chipping due to bending stress generation, and reduce stress in the rotor core. As a result, a highly reliable permanent magnet type reluctance type rotating electrical machine capable of high speed rotation is obtained.

  In addition, the outer peripheral side center locking projections can prevent contact between the outer peripheral divided permanent magnets and misalignment, thereby eliminating the need to place a bridge in the center and suppressing leakage magnetic flux. From this, it is possible to suppress torque reduction and to achieve high torque and high output.

  Since the inner permanent magnet can be symmetrical to the left and right, and an arch-shaped central permanent magnet can be used, the magnetic path shape of the rotor core is the same as before, ensuring high torque and high output characteristics utilizing reluctance torque. can do. In addition, the end permanent magnets arranged on both sides of the central permanent magnet can be formed into a flat plate shape having a quadrangular cross section, thereby improving magnet workability and reducing manufacturing costs.

  From the above, even when using a ferrite magnet that is inexpensive and weak in magnetic force, high torque, high output, and high-speed rotation are possible, and a highly reliable low-cost rotating electrical machine can be provided.

  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. 4 is an enlarged cross-sectional view of a part of the rotor of the permanent magnet type reluctance type rotating electrical machine 10 according to the second embodiment.

  In the present embodiment, in the permanent magnet on the inner peripheral side, the end permanent magnets 28b provided on both sides of the central permanent magnet 28a are formed in a trapezoidal shape having two non-parallel cross sections. Specifically, the trapezoidal end-side permanent magnet 28b has an inner thickness L3 along the extending direction of the fifth edge 55 of the portion along the fifth edge 55 of the portion located on the outer peripheral side of the rotor 14. It is comprised so that it may become thin with respect to thickness L4 along the extension direction of the 6th edge 56 of the part along the 6th edge 56 of the circumference side.

  In the second 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.

  The trapezoidal end-side permanent magnet 28b can increase the thickness of the portion located on the inner peripheral side of the rotor 14 with respect to the flat plate-shaped (rectangular) permanent magnet in the first embodiment. The cross-sectional area can be increased, and the magnet torque can be increased. Moreover, it becomes possible to make it a shape where the magnetic path width becomes larger toward the inner peripheral side as in the magnetic path shape of the conventional structure, and reluctance torque can be utilized.

  According to the second embodiment, the permanent magnet amount can be increased and the magnet torque can be increased by forming the end-side permanent magnet into a trapezoidal shape having two pairs of non-parallel sides. Moreover, the magnetic path shape of the rotor core is the same as that of the conventional one, and high torque and high output characteristics utilizing reluctance torque can be ensured. In the second embodiment, as in the first embodiment, a permanent magnet reluctance type rotating electrical machine that can rotate at high speed and has high reliability can be provided.

  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.

In the first embodiment, the central locking projection provided in the outer magnet receiving hole is a first position located on the rotation center side defining the outer receiving hole in a cross section perpendicular to the rotation center of the rotor core. It is formed in the 2nd edge located in the radial outside rather than the edge of. However, for example, a central locking projection may be provided in the inner peripheral side magnet accommodation hole. In this case, the central locking projection is located radially outside the third edge on the rotation center side of the rotor core that defines the inner magnet housing hole in a cross section perpendicular to the rotation center of the rotation core. It is formed in the 4th edge which prescribes | regulates an inner peripheral side magnet accommodation hole. More specifically, for example, when the divided magnets such as the divided permanent magnets 26a and 26b are accommodated in the central embedded hole 34a on the inner peripheral side, the fourth edge of the inner peripheral side magnetic embedded hole 34a. 54 may be provided with a central locking protrusion similar to the outer peripheral side central locking protrusion 36b.
Hereinafter, the invention described in the scope of claims at the beginning of the application of the present application will be added.
[1] A stator including a stator core and an armature winding attached to the stator core, and a rotor including a rotor core provided to be rotatable with respect to the stator.
The rotor iron core is formed with an inner magnet housing hole capable of housing a magnet, and an outer magnet housing hole capable of housing a magnet on a radially outer side of the rotor core than the inner magnet housing hole,
In the cross section of the rotor core perpendicular to the rotation center of the rotor core, the first edge on the rotation center side that defines the outer magnet housing hole, the outer side in the radial direction from the first edge Each of the second edges located is formed in a curve that is convex toward the rotation center side,
In the cross section of the rotor core perpendicular to the rotation center, a third edge on the rotation center side that defines the inner magnet housing hole, a fourth edge located radially outward from the third edge. Each of the edges is formed in a curve that is convex toward the rotation center side,
An outer peripheral side central locking projection that protrudes toward the first edge and that defines the position of the magnet by contacting the magnet is formed at a portion of the second edge that is most convex toward the rotation center. ,
Inner peripheral side locking projections projecting toward the second edge, which define the position of the magnet by contacting the magnet, are formed in the vicinity of both ends of the first edge,
The outer peripheral side central locking projection and the inner peripheral side near one end so that the cross section of the magnet perpendicular to the rotational center is axisymmetric with respect to a straight line connecting the rotational center and the outer peripheral side central locking projection A magnet can be fixed between the locking protrusion and the magnet can be fixed between the outer peripheral center locking protrusion and the inner peripheral locking protrusion near the other end.
Rotating electric machine characterized by that.
[2] The magnet fixed between the outer peripheral side central locking projection and the inner peripheral locking projection in the vicinity of the one end portion faces the surface including the first edge of the outer magnet receiving hole. A first surface that makes contact, a second surface that makes surface contact with a surface that includes the second edge of the outer peripheral side magnet housing hole, and a flat third surface that makes contact with the outer peripheral side central locking projection. And a flat fourth surface in contact with the inner peripheral side locking projection near the one end,
The magnet fixed between the outer peripheral side central locking projection and the inner peripheral locking projection in the vicinity of the other end is in surface contact with the surface including the first edge of the outer peripheral magnet receiving hole. A fifth surface, a sixth surface in surface contact with the surface including the second edge of the outer peripheral side magnet accommodation hole, a flat seventh surface in contact with the outer peripheral side central locking projection, A flat eighth surface in contact with the inner peripheral side locking projection in the vicinity of the other end.
The rotating electrical machine according to [1], wherein
[3] The rotor core is formed with at least one side magnet accommodation hole that can accommodate the magnet and is arranged in a direction in which the third edge extends with respect to the inner circumference side magnet accommodation hole.
The rotating electrical machine according to [1] or [2], wherein
[4] The rotor core has one side magnet housing formed on each side in the extending direction of the third edge with respect to the inner circumferential magnet housing hole.
In the cross section of the rotor core perpendicular to the center of rotation, the both-side magnet receiving holes extend in the extension direction of the third edge and in the extension direction of the third edge. And a sixth edge located closer to the center of rotation than the fifth edge,
The magnet housed in the both-side magnet housing hole has a seventh edge facing the fifth edge and an eighth edge facing the sixth edge in a cross section perpendicular to the rotation center. Formed in straight lines parallel to each other,
The magnet accommodated in the inner circumference side magnet accommodation hole is formed so that a cross section perpendicular to the rotation center is axisymmetric with respect to a straight line connecting the rotation center and the outer circumference side central projection.
The rotating electrical machine according to [3], wherein
[5] The rotating electrical machine according to [4], wherein the magnet housed in the side magnet housing hole has a trapezoidal cross section perpendicular to the rotation center.
[6] The magnet accommodated in the end-side magnet accommodation hole has a rectangular cross section perpendicular to the rotation center.
The rotating electric machine according to [5], wherein
[7] The thickness along the direction perpendicular to the fifth edge in the cross section perpendicular to the rotation center of the magnet accommodated in the side magnet accommodation hole is accommodated in the inner circumference side magnet accommodation hole. Less than the thickness along the direction perpendicular to the direction in which the third edge extends in the cross section perpendicular to the rotation center of the magnet
The rotating electric machine according to any one of [4] to [6].

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,
26a, 26b ... split permanent magnets, 28a ... center permanent magnets, 28b ... end side permanent magnets,
32 ... outer peripheral side magnet embedding hole, 32a ... outer peripheral surface, 32b ... inner peripheral surface,
34a ... center embedded hole, 34b ... end side embedded hole, 42a ... locking projection,
42b ... Outer peripheral side locking projection

Claims (7)

A stator having a stator core and an armature winding attached to the stator core;
A rotor having a rotor core provided rotatably with respect to the stator,
The rotor core is divided into two parts in the circumferential direction of the rotor core, the inner circumference side magnet accommodation hole capable of accommodating a central permanent magnet and the radially outer side of the rotor core than the inner circumference side magnet accommodation hole. an outer circumferential side magnet containing hole capable of containing permanent magnets, is formed,
In the cross section perpendicular the rotor core with respect to the rotation center of the rotor core, said first edge of the rotation center side, the radial direction than the first edge defining the outer circumferential side magnet containing hole each of the second edge located outside, is formed in a curve is convex prior Symbol rotation center side,
In the cross section of the rotor core perpendicular to the center of rotation, the third edge on the side of the center of rotation that defines the inner peripheral magnet receiving hole is located on the radially outer side of the third edge. Each of the fourth edges is formed in a curve that is convex toward the rotation center side,
The center of the outer peripheral side protruding toward the first edge that defines the position of the divided permanent magnet by contacting the divided permanent magnet at the portion that is most convex on the rotation center side in the second edge A locking projection is formed,
Inner peripheral side locking projections projecting toward the second edge, which define the position of the split permanent magnet by contacting the split permanent magnet, are formed near both ends of the first edge, respectively. And
The outer peripheral side central locking projection and the inner peripheral side near one end so that the cross section of the magnet perpendicular to the rotational center is axisymmetric with respect to a straight line connecting the rotational center and the outer peripheral side central locking projection between the locking projection and the rotating electric machine, wherein the divided permanent magnets are fixed respectively, that between the outer peripheral side central locking projection and the other end portion the inner circumferential side locking projection in the vicinity . The divided permanent magnet fixed between the outer peripheral side central locking projection and the inner peripheral locking projection in the vicinity of the one end portion faces the surface including the first edge of the outer magnet receiving hole. A first surface that makes contact, a second surface that makes surface contact with a surface that includes the second edge of the outer peripheral side magnet housing hole, and a flat third surface that makes contact with the outer peripheral side central locking projection. And a flat fourth surface in contact with the inner peripheral side locking projection near the one end,
The divided permanent magnet fixed between the outer peripheral side central locking projection and the inner peripheral locking projection in the vicinity of the other end is formed on a surface including the first edge of the outer magnet receiving hole. A fifth surface in surface contact, a sixth surface in surface contact with the surface including the second edge of the outer magnet receiving hole, and a flat seventh surface in contact with the outer central locking projection. The rotating electrical machine according to claim 1, further comprising: a flat eighth surface that comes into contact with the inner peripheral side locking protrusion in the vicinity of the other end portion. The rotor core is formed with at least one side magnet accommodation hole that is capable of accommodating an end-side permanent magnet that is arranged in a direction in which the third edge extends with respect to the inner circumference magnet accommodation hole. the rotating electrical machine according to claim 1 or claim 2,. The rotor core, said lateral magnet containing holes in opposite sides of extension of said third edge to said inner circumference side magnet containing holes are formed one by one,
In a cross section perpendicular the rotor core with respect to the rotation center, front SL side magnet containing hole, a fifth edge extending in the extending direction of the third edge, the extending direction of the fourth edge A sixth edge extending and positioned radially outward from the fifth edge,
The end permanent magnets accommodated in the front SL side magnet containing hole, in a cross section perpendicular to the rotation center, a seventh edge opposing said fifth edge, the opposite to the sixth edge 8 edges are formed in a straight line parallel to each other,
The central permanent magnet housed in the inner circumferential magnet housing hole has a cross section perpendicular to the rotation center formed in a line-symmetric shape with respect to a straight line connecting the rotation center and the outer circumferential center locking projection. The rotating electrical machine according to claim 3. The rotating electrical machine according to claim 4, wherein the end-side permanent magnet housed in the side magnet housing hole has a trapezoidal cross section perpendicular to the rotation center. 6. The rotating electrical machine according to claim 5, wherein the end-side permanent magnet housed in the side magnet housing hole has a rectangular cross section perpendicular to the rotation center. The thickness along the direction perpendicular to the fifth edge in the cross section perpendicular to the rotation center of the end-side permanent magnet accommodated in the side magnet accommodation hole is accommodated in the inner circumferential magnet accommodation hole. It said central than the thickness along the direction perpendicular to the third edge extending direction in a cross section perpendicular to the rotational center of the permanent magnet, of the claims 4 to 6, characterized in that small that The rotating electrical machine according to any one of claims.

Images