JP2021122163A - Rotary electric machine - Google Patents

Abstract

To provide a rotary electric machine that can suppress the demagnetization of a permanent magnet.SOLUTION: A rotor core (12) comprises: first magnet insertion holes (13a) into each of which a first permanent magnet (14a) having an arc cross section is inserted; and second magnet insertion holes (13b and 13c), extending from the inside to outside of a rotor (3) in the radial direction, into which second permanent magnets (14b and 14c), each having a rectangular cross section and extending from the inside to outside in the radial direction, are inserted. Each magnetic pole of the rotor (3) is configured of one first permanent magnet (14a) and two second permanent magnets (14b and 14c) arranged in line symmetry to the radial direction of the rotor (3). The second magnet insertion holes (13b and 13c) have air gap portions (20b and 20c) at the outside end of the rotor (3) in the radial direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a rotating electric machine having a permanent magnet for a field magnet in a rotor.

In recent years, permanent magnets have been used as field magnets in rotary electric machines to improve their compactness and efficiency. As a means for reducing the size and increasing the efficiency of a rotating electric machine in which a permanent magnet is used, it is possible to increase the surface area of the permanent magnet along the direction of the rotation axis and increase the amount of magnetic flux of the permanent magnet. Then, as one of the means for increasing the amount of magnetic flux of the permanent magnet, the shape and arrangement of the permanent magnet may be devised.

As a conventional technique relating to the shape and arrangement of permanent magnets used in a rotary electric machine, for example, the technique described in Patent Document 1 (FIG. 1) is known. In this conventional technique, a permanent magnet embedded in the rotor extends toward the outer peripheral surface of the rotor from an arcuate central portion that is convex inward in the radial direction of the rotor and both ends of the central portion. It has a plurality of linear side portions. Due to the shape and arrangement of the permanent magnets, the amount of magnetic flux obtained by magnetism is secured at the bent portion between the central portion of the arc shape and the side portion of the linear shape, and the amount of magnetic flux can be increased.

Japanese Unexamined Patent Publication No. 2016-171646

However, in the above-mentioned conventional technique, there is a problem that the tip portion of the plurality of linear side portions of the permanent magnet located on the outer peripheral side of the rotor is easily demagnetized by the magnetic field generated by the armature winding included in the stator. Therefore, the torque characteristics of the permanent magnet may be deteriorated.

Therefore, the present invention provides a rotary electric machine capable of suppressing demagnetization of a permanent magnet.

In order to solve the above problems, the rotor electric machine according to the present invention has a stator core, a stator having an armature winding wound around the stator core, a rotor core, and the rotor core. A plurality of permanent magnets to be embedded and a rotor having a rotating shaft fixed to the rotor core are provided, and the plurality of permanent magnets are convex inward in the radial direction of the rotor. A plurality of first permanent magnets having an arcuate cross section, and a plurality of second permanent magnets having a rectangular cross section and the rectangular cross section extending from the radial inside to the radial outside of the rotor. The rotor core includes a plurality of first magnet insertion holes into which the plurality of first permanent magnets are inserted, and a plurality of second magnet insertion holes into which the plurality of second permanent magnets are inserted. Each of the plurality of magnetic poles of the rotor has one first permanent magnet and two second permanent magnets, and the second permanent magnets are arranged on both sides of the first permanent magnet. Moreover, the second magnet insertion hole is arranged linearly symmetrically with respect to the radial direction of the rotor, and the second magnet insertion hole has a gap portion at an end portion on the outer side in the radial direction of the rotor.

Further, in order to solve the above problems, the rotor electric machine according to the present invention includes a rotor core, a stator having an armature winding wound around the stator core, a rotor core, and the rotor. It includes only two permanent magnets per magnetic pole embedded in the iron core and a rotor having a rotor shaft fixed to the rotor core, and the two permanent magnets have a rectangular cross section. The rectangular cross section extends from the radially inner side of the rotor toward the radial outer side, and the rotor core has two magnet insertion holes into which the two permanent magnets are inserted. Each of the plurality of magnetic poles of the rotor is configured such that the two permanent magnets are arranged line-symmetrically with respect to the radial direction of the rotor, and the magnet insertion holes are radially outside the rotor. The rotor core has a gap portion at an end, the rotor core has a first bridge portion interposed between the outermost outer peripheral surface of the rotor and the gap portion, and the first bridge portion is the rotor. Of the two inner wall surfaces along the circumferential direction of the rotor and along the radial direction of the rotor in the gap, the length of one inner wall surface located on the d-axis side, which is the magnetic flux axis of the magnetic pole. Assuming that L1 is the length L2 of the other inner wall surface located on the side of the q-axis orthogonal to the magnetic flux axis in terms of electric angle, L1 <L2.

According to the present invention, demagnetization of a permanent magnet can be suppressed.

Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is sectional drawing in the direction perpendicular to the axial direction of the stator and the rotor of the rotary electric machine which is 1st Example. It is sectional drawing in the axial direction of the rotary electric machine 1 shown in FIG. It is sectional drawing in the direction perpendicular to the axial direction of the rotor of the rotary electric machine which is 1st Example. FIG. 3 is a partial cross-sectional view showing a cross section of one magnetic pole in the rotor cross section shown in FIG. It is a torque characteristic diagram of the rotary electric machine of an Example. It is a partial cross-sectional view in the direction perpendicular to the axial direction of the rotor of the rotary electric machine which is the 2nd Example. It is a partial cross-sectional view in the direction perpendicular to the axial direction of the rotor of the rotary electric machine which is the 3rd Example. It is a partial cross-sectional view in the direction perpendicular to the axial direction of the rotor of the rotary electric machine which is the 4th Example. It is a partial cross-sectional view in the direction perpendicular to the axial direction of the rotor of the rotary electric machine which is a fifth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the following Examples 1 to 5 with reference to the drawings. In each figure, those having the same reference number indicate the same constituent requirements or constituent requirements having similar functions.

Each embodiment is an embedded magnet type rotary electric machine in which a permanent magnet is embedded in a rotor core, and operates as a synchronous motor. Further, in each embodiment, the number of magnetic poles of the rotor is 8 and the number of slots of the stator is 48. The combination of the number of magnetic poles and the number of slots is not limited to "8 poles, 48 slots" and can be appropriately set according to desired motor characteristics.

Further, in the present specification, the "axial direction" indicates the rotation axis direction of the rotor, the "diametrical direction" indicates the radial direction of the rotor, and the "circumferential direction" indicates the circumferential direction of the rotor.

First, with reference to FIGS. 1 and 2, the overall configuration of the rotary electric machine according to the first embodiment of the present invention will be schematically described.

FIG. 1 is a cross-sectional view of a stator and a rotor of a rotary electric machine according to a first embodiment of the present invention in a direction perpendicular to the axial direction.

As shown in FIG. 1, the rotary electric machine 1 is composed of a stator 2 and a rotor 3 rotatably arranged inside the stator 2 through a predetermined gap. The rotor 3 is fixedly provided with a rotating shaft 15 that is mechanically connected to the load.

The stator 2 has a stator core 6 made of a magnetic material. The stator core 6 includes a core back 5 and a plurality of teeth 4 protruding inward in the radial direction from the core back 5. The plurality of teeth 4 are connected by a core back 5 on the outer peripheral side along the radial direction thereof. Further, the plurality of teeth 4 are arranged at equal intervals in the circumferential direction. An armature winding (not shown in FIG. 1), which is a three-phase winding, is wound between two teeth 4 adjacent to each other in the circumferential direction so as to open toward the outermost outer peripheral surface 3b of the rotor 3. The stator slot 7 is provided.

In this embodiment, the armature windings are wound in a plurality of slots (48 in this embodiment) in a distributed winding manner. The armature winding may be a centralized winding.

The rotor 3 has a rotor core 12 made of a magnetic material and a plurality of permanent magnets embedded in the rotor core 12. One magnetic pole of the rotor 3 is composed of three permanent magnets (14a, 14b, 14c). In this embodiment, as shown in FIG. 1, eight sets of permanent magnets form an eight-pole magnetic pole. The permanent magnets (14a, 14b, 14c) are inserted into the magnet insertion holes (13a, 13b, 13c) from the axial direction of the rotating shaft 15. A more detailed configuration of the rotor 3 will be described later.

FIG. 2 is a cross-sectional view of the rotary electric machine 1 shown in FIG. 1 in the axial direction. In FIG. 2, the case, frame, bearing, etc. that support the stator 2 and the rotor 3 are not shown.

As shown in FIG. 2, the stator core 6 and the rotor core 12 are composed of a laminated body in which a plurality of thin plates 30 made of a magnetic material such as a silicon steel plate are laminated. As a result, iron loss such as eddy current loss generated in the stator core 6 and the columnar rotor core 12 is reduced. The plurality of thin plates 30 are joined to each other and integrated by welding, caulking, or the like. The stator slot 7 penetrates the stator core 6 along the axial direction. Further, the magnet insertion holes (13a, 13b, 13c) penetrate the rotor core 12 along the axial direction.

In the plurality of conductor strands constituting the armature winding 40, a portion passing through the stator slot 7 constitutes a coil side, and a portion protruding from the stator slot 7 to the outside of the stator 2 constitutes a coil end.

The permanent magnets (14a, 14b, 14c) are single plate-shaped (rectangular cross-section) magnets whose axial length is equivalent to that of the magnet insertion holes (13a, 13b, 13c). In this embodiment, the permanent magnets (14a, 14b, 14c) are relatively inexpensive ferrite permanent magnets.

The permanent magnets (14a, 14b, 14c) may be divided into a plurality of pieces in the axial direction. Further, as the permanent magnets (14a, 14b, 14c), rare earth magnets such as neodymium magnets may be used.

In such a rotating electric machine 1, a rotating magnetic field is generated when a three-phase AC current is passed through the armature winding of the stator 2. The rotor 3 is rotated by the electromagnetic force acting on the rotor 3 by this rotating magnetic field. As a result, the rotary electric machine 1 operates as a synchronous motor.

Next, the detailed configuration of the rotor in this embodiment will be described with reference to FIGS. 3 and 4.

FIG. 3 is a cross-sectional view in a direction perpendicular to the axial direction of the rotor of the rotary electric machine according to the first embodiment of the present invention.

As shown in FIG. 3, a gap having a gap length g1 is interposed in the radial direction between the outermost outer peripheral surface 3b of the rotor core 12 and the inner peripheral surface of the teeth 4.

In the rotor cross section shown in FIG. 3, three magnet insertion holes for one magnetic pole, that is, a magnet insertion hole (13a) having an arcuate cross section and a magnet insertion having a linear cross section when viewed from the axial direction of the rotary shaft 15. The holes (13b, 13c) are arranged in a substantially U-shape or a substantially V-shape. A ferrite permanent magnet having a cross-sectional shape similar to that of the magnet insertion hole is inserted into each magnet insertion hole.

Here, as shown in FIG. 3, at one magnetic pole, the d-axis is defined so that the rotation center of the rotor 3 is the starting point (O) in the direction of the magnetic flux generated by the permanent magnet, and the electric angle is orthogonal to the d-axis. The q-axis is determined so that the rotation center of the rotor 3 is the starting point (O) in the direction of rotation. In this embodiment, since the d-axis and the q-axis start from the center of rotation, the directions of the d-axis and the q-axis are also radial directions. Further, the q-axis is interposed between two adjacent magnetic poles and passes through the center thereof. Therefore, as the q-axis, the q-axis on the side permanent magnet 14c side shown with the d-axis as the axis of symmetry and the q-axis on the side permanent magnet 14b side (not shown) located line-symmetrically. There is an axis.

In the cross section of the rotor 3 shown in FIG. 3, the permanent magnets (14a, 14b, 14c) are axisymmetric (left-right symmetric) with respect to the axis of symmetry that is radially oriented and passes through the center of rotation of the rotor 3, that is, the d-axis. ) Is placed. In this embodiment, the permanent magnets (14a, 14b, 14c) are arranged in a substantially U-shape or a substantially V-shape as described above, but the U-shape or V-shape is inward in the radial direction. It means that it is arranged so as to be convex toward the outside and open toward the outside in the radial direction.

FIG. 4 is a partial cross-sectional view showing a cross section of one magnetic pole in the rotor cross section shown in FIG.

As shown in FIG. 4, the set of permanent magnets constituting one magnetic pole is three permanent magnets, that is, an arc-shaped central permanent magnet (first permanent magnet) that is convex inward in the radial direction of the rotor. ) 14a and two linear side permanent magnets extending from the central permanent magnet 14a in the tangential direction at the end of the central permanent magnet 14a from the radial inside to the radial outside of the rotor 3 ( Second permanent magnets) 14b, 14c and the like. These plurality of permanent magnets, that is, the side permanent magnets 14b, the central permanent magnets 14a, and the side permanent magnets 14c in this embodiment are arranged in this order. That is, in this embodiment, in these plurality of permanent magnets, one end of the side permanent magnet 14b and one end of the central permanent magnet 14a face each other, and the other end of the central permanent magnet 14a and the side permanent magnet 14c It is arranged so that one end of the magnet is opposed to the magnet.

The central angle of the arc-shaped central permanent magnet 14a is smaller than 180 degrees, and the side permanent magnets 14b and 14c are arranged so as to open from the inside in the radial direction to the outside in the radial direction.

According to the shape and arrangement of such permanent magnets, the portion 10 between the side permanent magnets 14b and 14c in the rotor core 12 while setting the surface area of the permanent magnets constituting the magnetic poles to a desired value (FIG. 3). ) Is large, so the reluctance torque can be improved.

Further, according to the shape and arrangement of the permanent magnets in this embodiment, the bent portion between the arc-shaped central permanent magnet and the linear side permanent magnet is similar to the technique described in Patent Document 1 described above. In, the amount of magnetic flux obtained by magnetization is secured. This state is shown in FIG. 4 as a magnet surface magnetic flux φm (arrows marked on the surface of each magnet in the figure). As shown in the figure, when the direction of φm is linear between the end of the central permanent magnet 14a and the radial inner ends of the side permanent magnets 14b and 14c, for example, the central permanent magnet. (See Patent Document 1). Magnetization is reliably performed at the bent portion between the arc-shaped central permanent magnet and the linear side permanent magnet. As a result, the amount of magnetic flux is secured, and the amount of magnetic flux corresponding to the surface area of the permanent magnet can be obtained.

As shown in FIG. 4, the distance between the arc-shaped central permanent magnet 14a and the radial outermost circumference 3a of the rotating shaft 15 is L3, the radial width of the central permanent magnet 14a is L4, and the central permanent magnet 14a. Assuming that the distance between the outer peripheral surface of the rotor 3 and the outermost outer peripheral surface 3b of the rotor 3 is L5, it is preferable that L3, L4, and L5 have the following relationship.

First, by setting L3 ≦ L4 <L5, the surface area of the permanent magnets is increased, and the amount of magnetic flux cancellation at the ends of the central permanent magnets 14a and the radial inner ends of the side permanent magnets 14b and 14c is increased. It can be suppressed.

Further, by setting L4 ≦ L3, the permanent magnet 14a at the center can be brought closer to the outer side in the radial direction of the rotor to facilitate magnetization. In this embodiment, magnetization is performed by arranging a plurality of windings outside the rotor in which the magnetic members constituting the permanent magnets are embedded and supplying a current to those windings.

Further, by setting L4 ≦ L3 <L5, the central permanent magnet 14a is brought closer to the outer side in the radial direction of the rotor to facilitate magnetization while suppressing the expansion of the surface area of the permanent magnet and the amount of magnetic flux canceling. Can be.

Further, in this embodiment, three magnet insertion holes, that is, arc-shaped central magnet insertion holes (first magnet insertion holes) that are convex inward in the radial direction of the rotor in the rotor core 12 for one magnetic pole. ) 13a and two linear side magnet insertion holes extending from the central magnet insertion hole 13a in the tangential direction of the central magnet insertion hole 13a from the radial inside to the radial outside of the rotor 3 ( Second magnet insertion holes) 13b and 13c are provided. A central permanent magnet 14a, a side permanent magnet 14b, and a side permanent magnet 14c are inserted and fixed to the central magnet insertion hole 13a, the side magnet insertion hole 13b, and the side magnet insertion hole 13c, respectively. .. The central magnet insertion hole 13a, the side magnet insertion hole 13b, and the side magnet insertion hole 13c insert the central permanent magnet 14a, the side permanent magnet 14b, and the side permanent magnet 14c in the rotor core 12. As possible, they are arranged at the same positions as the central permanent magnet 14a, the side permanent magnets 14b, and the side permanent magnets 14c, respectively, as described above.

The central permanent magnet 14a, the side permanent magnet 14b, and the side permanent magnet 14c are included in the central magnet insertion hole 13a, the side magnet insertion hole 13b, and the side magnet insertion hole 13c, respectively, by fitting or bonding. It touches the wall. As a result, the central permanent magnet 14a, the side permanent magnet 14b, and the side permanent magnet 14c are fixed in the central magnet insertion hole 13a, the side magnet insertion hole 13b, and the side magnet insertion hole 13c, respectively. NS.

Of the three magnet insertion holes, the side magnet insertion holes 13b and 13c are voids 20b, in which the side permanent magnets 14b and 14c are not located at the radial outer ends of both ends thereof. Has 20c. The gaps 20b and 20c extend radially outward from the region where the side permanent magnets 14b and 14c are located in the side magnet insertion holes 13b and 13c. A part of the rotor core 12 is interposed between the gaps 20b and 20c and the outermost surface 3b of the rotor core 12, and the outermost bridge portions (first bridge portions) 16b and 16c are configured. Will be done.

The circumferential width of the gaps 20b and 20c is equivalent to the circumferential width of the region where the side permanent magnets 14b and 14c are located in the side magnet insertion holes 13b and 13c. That is, in the gaps 20b and 20c, of the inner wall surfaces of the side magnet insertion holes 13b and 13c, the two inner wall surfaces of the side magnet insertion holes 13b and 13c in the longitudinal direction are the side permanent magnets 14b and 14c. It extends linearly from one end of the radial outer side of both ends of the located region toward the radial outer side.

Further, the inner wall surfaces 20b1 and 20c1 in the circumferential direction, which are the ends of the gaps 20b and 20c on the outer side in the radial direction, are located at positions separated from the outermost outer peripheral surface 3b of the rotor core 12 by a predetermined distance inward in the radial direction. It is located along the outermost outer peripheral surface 3b of 12. As a result, a part of the rotor core 12 is interposed between the gaps 20b and 20c and the outermost surface 3b of the rotor core 12, and the outermost bridge portions 16b and 16c are formed.

As shown in FIG. 4, the long sides of the side permanent magnets 14b and 14c are in the radial direction (although they are slightly deviated from the radial direction in FIG. 4, they are "diametrically" for convenience in the sense of "approximately radial direction". It has a rectangular (rectangular) cross section extending to (referred to as). Here, as shown in FIG. 4, the inner wall surface 20b2 on the rotor core 12 side, that is, the d-axis side, located between the side permanent magnets 14b and 14c among the two inner wall surfaces in the radial direction of the gap portions 20b and 20c. The radial length of 20c2 is L1, and the radial length of the inner wall surfaces 20b3 and 20c3 on the adjacent magnetic pole side, that is, the q-axis side is L2. The magnitude relationship between L1 and L2 is L1 <L2 in this embodiment.

These L1 and L2 are, so to speak, the terminal surfaces 14b1 and 14c1 on the outer side in the radial direction and the gap portion 20b among the two terminal surfaces of the side permanent magnets 14b and 14c perpendicular to the longitudinal direction of the side permanent magnets. It is also the distance (L1) from the end on the d-axis side and the distance (L2) from the end on the q-axis side on the inner wall surfaces 20b1 and 20c1 of 20c. Therefore, by setting L1 <L2, the radial widths 16bt and 16ct of the outermost outermost bridge portions 16b and 16c can be set to substantially uniform dimensions along the circumferential direction, that is, substantially constant values.

In this embodiment, as shown in FIG. 4, the overall cross-sectional shape of the side magnet insertion holes 13b and 13c having the gaps 20b and 20c as described above is elongated with the radial direction as the longitudinal direction. It is trapezoidal. In this trapezoid, the two sides extending in the longitudinal direction are parallel to each other (that is, the upper base and the lower base of the trapezoid), and one of the other two sides (that is, the legs of the trapezoid) is located on the inner side in the radial direction (that is, one side). One leg) forms a right angle with two parallel sides. Of the two sides parallel to each other, one side of the rotor core 12 side, that is, the d-axis side, which is located between the side magnet insertion holes 13b and 13c, is shorter than one side of the adjacent magnetic pole side, that is, the q-axis side.

The above-mentioned gaps 20b and 20c have a higher magnetic resistance than the rotor core 12 around them, and the magnetic flux density generated in the vicinity of the outermost outer peripheral surface 3b of the rotor core 12 by the armature winding wound around the teeth 4. High magnetic flux φs is hard to penetrate. Therefore, since the terminal surfaces 14b1, 14c1 on the radial outer side of the side permanent magnets 14b, 14c are separated from the magnetic flux φs, demagnetization of the radial outer ends of the side permanent magnets 14b, 14c can be prevented.

Further, in this embodiment, by providing the gap portions 20b and 20c, the radial width of the outermost peripheral side bridge portions 16b and 16c can be set to substantially uniform dimensions along the circumferential direction. As a result, as shown in the A portion (the region within the dotted line circle) in FIG. 4, the magnetic flux φs due to the armature winding passes through the outermost peripheral side bridge portions 16b and 16c. As a result, the radial outer end surfaces 14b1, 14c1 of the side permanent magnets 14b, 14c are surely separated from the magnetic flux φs by the amount provided with the gaps 20b, 20c. Therefore, demagnetization of the radial outer ends of the side permanent magnets 14b and 14c can be reliably prevented.

Further, since demagnetization of the outer end portion in the radial direction can be prevented, the harmonic component of the full interchain magnetic flux due to the armature reaction can be reduced.

Further, since the gap portions 20b and 20c are interposed between the radial outer ends of the side permanent magnets 14b and 14c and the outermost peripheral bridge portions 16b and 16c, the diameters of the side permanent magnets 14b and 14c Leakage flux at the end outside the direction can be reduced. Therefore, it is possible to prevent the magnet magnetic flux that contributes to torque from being reduced by the leakage flux.

The gaps 20b and 20c are, so to speak, magnetic barriers to magnetic flux and leakage flux due to the armature winding. Therefore, the voids 20b and 20c may be filled with a non-magnetic solid substance such as resin.

Further, since the radial widths of the outermost peripheral side bridge portions 16b and 16c can be set to substantially uniform dimensions along the circumferential direction, the rotor 3 has the rotor outermost peripheral side bridge portion even though the rotor core has the outermost peripheral side bridge portion. It is possible to prevent a decrease in mechanical strength of.

Further, in this embodiment, at the radial inner ends of the side magnet insertion holes 13b and 13c and both ends of the central magnet insertion holes 13a in the direction along the arc, the more the inside of the rotor core 12 becomes. Since it becomes difficult for the magnetic flux φs to enter, a gap for preventing demagnetization is not provided. Therefore, the radial inner end surfaces 14b2 and 14c2 of the side permanent magnets 14b and 14c are in contact with the radial inner end inner wall surfaces 13b2 and 13c2 of the side magnet insertion holes 13b and 13c. In other words, the radially inner short side of the rectangular cross section of the side permanent magnets 14b, 14c is in contact with the radially inner leg of the trapezoidal cross section of the side magnet insertion holes 13b, 13c. Further, both end surfaces 14a1 of the central permanent magnet 14a in the direction along the arc are in contact with the end inner wall surface 13a1 in the direction along the arc of the central magnet insertion hole 13a. As a result, since the end portion of the permanent magnet is supported by the rotor core 12, micro-vibration (rattling) of the permanent magnet is prevented. Therefore, breakage of the permanent magnet and the like is prevented, and the mechanical durability of the rotor 3 is improved.

In this embodiment, the permanent magnets (14a, 14b, 14c) are fixed and in contact with the inner wall of the magnet insertion holes (13a, 13b, 13c) with an adhesive. The permanent magnets (14a, 14b, 14c) may be fixed to the inner wall of the magnet insertion holes (13a, 13b, 13c) by press fitting or the like and may be in direct contact with the inner wall.

Further, in this embodiment, as shown in FIG. 4, a rotor is provided between the radial inner ends of the side magnet insertion holes 13b and 13c and both ends of the central magnet insertion holes 13a in the direction along the arc. A part of the iron core 12 is interposed to form an inner peripheral side bridge portion (second bridge portion) 16a. The radial width 16at of the inner peripheral side bridge portion 16a is set to a substantially constant predetermined value between both end portions in the circumferential direction. This predetermined value is preferably set to a thickness so that the inner peripheral side bridge portion 16a does not mechanically yield due to centrifugal force when the rotary electric machine 1 is driven and the rotor 3 rotates.
By providing such an inner peripheral side bridge portion 16a, stress concentration at the outermost peripheral side bridge portions 16b and 16c of the rotor core 12 can be suppressed when a centrifugal force acts on the rotor core 12, so that the rotor Mechanical strength is improved.

FIG. 5 is a torque characteristic diagram of the rotary electric machine of this embodiment. The characteristic diagram of FIG. 5 is the result of a study by the present inventor.

In FIG. 5, the vertical axis and the horizontal axis represent torque and armature current as per unit values (PU), respectively. For comparison, a rotary electric machine according to the technique described in Patent Document 1 described above, that is, a rotary electric machine having no gap at the radial outer peripheral side end of the side magnet insertion hole is used as a comparative example, and its torque characteristics are shown. show.

As shown in FIG. 5, according to this embodiment, the torque of the rotary electric machine is improved.

With these configurations, the surface area of the permanent magnet can be increased without deteriorating the torque characteristics in the high-speed range, and it becomes possible to provide a compact and highly efficient rotary electric machine 1. Further, in the high speed range, even when the load is high and the armature winding is increased to increase the inductance, the harmonic component of the in-machine magnetic flux due to the armature reaction is reduced, and the torque can be increased by improving the power factor. In addition, it is possible to suppress a decrease in the amount of magnetic flux due to demagnetization of the permanent magnet due to the reaction of the armature. Further, the peripheral end portion (second bridge portion) of the permanent magnet insertion hole and the permanent magnet can be prevented from being damaged, and a compact and highly efficient rotary electric machine can be provided.

As described above, according to the present embodiment, since the demagnetization of the permanent magnet is suppressed, a magnet magnetic flux corresponding to the surface area of the permanent magnet can be obtained. As a result, the torque of the rotary electric machine can be improved and the rotary electric machine can be miniaturized. Further, since the harmonic component of the full interlinkage magnetic flux due to the armature reaction can be reduced, the generation of torque pulsation and electromagnetic noise can be suppressed. Further, since the mechanical strength of the rotor is improved, the speed of the rotating electric machine can be increased in combination with the improvement of the torque.

It should be noted that this embodiment is suitable for a rotary electric machine to which a ferrite magnet, which has a larger effect of canceling magnet magnetic flux and demagnetization as described above, is larger than that of a rare earth magnet.

FIG. 6 is a partial cross-sectional view in a direction perpendicular to the axial direction of the rotor of the rotary electric machine according to the second embodiment of the present invention. Note that FIG. 6 shows a cross section of one magnetic pole in the cross section of the rotor.

Hereinafter, the points different from the above-described first embodiment will be described.

As shown in FIG. 6, in this embodiment, the circumferential width of the gaps 20b and 20c is the circumferential width of the region where the side permanent magnets 14b and 14c are located in the side magnet insertion holes 13b and 13c. Narrower than.

More specifically, in the gap portions 20b'and 20c', the inner wall surface on the d-axis side and the inner wall surface on the q-axis side in the longitudinal direction of the side magnet insertion holes 13b and 13c is the third. Similar to the first embodiment (FIG. 4), the side permanent magnets 14b and 14c extend linearly from one end of the radial outer side of both ends of the region where the side permanent magnets 14b and 14c are located to the radial outer side. On the other hand, the inner wall surface on the q-axis side bends to the d-axis side along the radial outer side of the side permanent magnets 14b and 14c and along the corners on the q-axis side, and further, the diameters of the side permanent magnets 14b and 14c. Within the end plane on the outer side of the direction, it bends in the direction perpendicular to the end face, that is, in the radial outer direction, and extends in the same direction.

As a result, gaps 20b'and 20c', which are narrow in the circumferential direction, are formed, and the side permanent magnets 14b, A part of the radial outer end surface of 14c is in contact with the inner wall surfaces of the side magnet insertion holes 13b and 13c. In this way, the movement of the side permanent magnets 14b and 14c in the radial direction is restricted in the side magnet insertion holes 13b and 13c. Therefore, since the side permanent magnets 14b and 14c are supported by the rotor core 12, damage to the permanent magnets due to centrifugal force is prevented. Therefore, the mechanical strength of the rotor 3 is improved.

Further, the corner portions of the gap portions 20b'and 20c' that are in contact with the outermost peripheral side bridge portions 16b and 16c are curved in an arc shape. Further, the gap portions 20b'and 20c' are projecting portions 21b and 21c that project in an arc shape toward the q-axis at the portions adjacent to the corners on the radial outer side and the q-axis side of the side permanent magnets 14b and 14c. Has. As a result, stress concentration when the side permanent magnets 14b and 14c come into contact with the inner wall surface of the side magnet insertion holes 13b and 13c can be suppressed. Therefore, the mechanical strength of the rotor 3 is improved.

Further, as shown in FIG. 6, in the present embodiment, the side magnet insertion holes 13b and 13c have the same configurations as the gaps 20b'and 20c' and the protrusions 21b and 21c at the radial inner ends. The gap portions 23b and 23c and the protruding portions 22b and 22c are provided. Further, the central magnet insertion hole 13a includes gaps 20a and protrusions 21a at both ends in the direction along the arc.

According to the gaps 23b, 23c, 20a, the leakage flux at the end of the permanent magnet can be suppressed. Further, the arc-shaped protrusions 22b, 22c, 21a can suppress stress concentration in the region of the rotor core 12 in contact with the side magnet insertion holes 13b, 13c and the central magnet insertion hole 13a.

FIG. 7 is a partial cross-sectional view in a direction perpendicular to the axial direction of the rotor of the rotary electric machine according to the third embodiment of the present invention. Note that FIG. 7 shows a cross section of one magnetic pole in the cross section of the rotor.

Hereinafter, the points different from the above-mentioned second embodiment will be described.

In this embodiment, unlike the second embodiment (FIG. 6), one side permanent magnet (14b, 14c in FIG. 6) is composed of a plurality of unit side permanent magnets.

That is, as shown in FIG. 7, two unit side permanent magnets 14b1 and 14b2 having the same shape are inserted into the side magnet insertion holes 13b. The unit side permanent magnets 14b1 and 14b2 are in contact with each other in the radial direction and function as one side permanent magnet. Further, two unit side permanent magnets 14c1 and 14c2 having the same shape are inserted into the side magnet insertion holes 13c. The unit side permanent magnets 14c1 and 14c2 are in contact with each other in the radial direction and function as one side permanent magnet. The unit side permanent magnets may be divided into three or more to function as one side permanent magnet.

As described above, according to this embodiment, the total surface magnetic flux amount of the permanent magnets can be easily set by the number of permanent magnets on the unit side.

FIG. 8 is a partial cross-sectional view in a direction perpendicular to the axial direction of the rotor of the rotary electric machine according to the fourth embodiment of the present invention. Note that FIG. 8 shows a cross section of one magnetic pole in the cross section of the rotor.

Hereinafter, the points different from the above-mentioned second embodiment will be described.

In this embodiment, unlike the second embodiment (FIG. 6), the central magnet insertion hole 13a and the central permanent magnet 14a are formed on the outermost outer peripheral surface 3b of the rotor 3 and the side permanent magnets 14b and 14c. It is located within the region of the rotor core 12 with the radially inner end. That is, the central magnet insertion hole 13a and the central permanent magnet 14a are arranged along the d-axis direction, that is, the radial direction of the rotor 3, with the outermost outer peripheral surface 3b of the rotor 3 and the radial directions of the side permanent magnets 14b and 14c. Located between the inner edge. In this embodiment, as shown in FIG. 7, the central magnet insertion hole 13a and the central permanent magnet 14a are radial in the d-axis direction with respect to the radial inner ends of the side magnet insertion holes 13b and 13c. Located on the side closer to the outer edge.

According to this embodiment, the central magnet insertion hole 13a and the central permanent magnet 14a can be brought closer to the outer peripheral side of the rotor core, that is, the armature winding side, so that the magnetic members constituting each permanent magnet are embedded. When a plurality of windings are arranged outside the rotor and magnetized, the permanent magnet can be easily magnetized.

FIG. 9 is a partial cross-sectional view in a direction perpendicular to the axial direction of the rotor of the rotary electric machine according to the fifth embodiment of the present invention. FIG. 9 shows a cross section of one magnetic pole in the cross section of the rotor.

Hereinafter, the points different from the above-mentioned second embodiment will be described.

In the rotary electric machine of the present embodiment, so to speak, the central magnet insertion hole 13a and the central permanent magnet 14a are removed from the rotor 3 of the second embodiment (FIG. 6). That is, as shown in FIG. 9, one magnetic pole is composed of only two side permanent magnets 14b and 14c.

In this embodiment, the side permanent magnets 14b and 14c are made of ferrite. Therefore, in order to obtain a desired magnetic flux, the length of the long side of the rectangular cross section of the side permanent magnets 14b, 14c is adjusted, or the length of the short side of the rectangular cross section of the side permanent magnets 14b, 14c is adjusted. Adjust it. In this embodiment, the degree of freedom in setting the length of the short side of the rectangular cross section of the side permanent magnets 14b, 14c is improved, and the length of the short side of the rectangular cross section of the ferrite side permanent magnets 14b, 14c is increased. It can be easily increased. As a result, a desired magnetic flux can be obtained by the side permanent magnets 14b and 14c made of ferrite.

The two side permanent magnets 14b and 14c are arranged line-symmetrically with the d-axis as the axis of symmetry, as in each of the above-described embodiments. Therefore, the inner peripheral side bridge portion 16a is located on the d-axis.

The gap portion 23b and the gap portion 23c have an inner wall surface parallel to the d-axis. These inner wall surfaces are located so as to be parallel to each other. As a result, the width of the inner peripheral side bridge portion 16a in the circumferential direction is set to a substantially constant predetermined value along the d-axis.

Further, according to the fifth embodiment, as in each embodiment, demagnetization at the radial outer ends of the side permanent magnets 14b and 14c is prevented.

The present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described examples have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

For example, the permanent magnet may be a sintered magnet or a bonded magnet. Further, the stator core and the rotor core may be made of a bulk material.

1 Rotor, 2 Stator, 3 Rotor, 4 Teeth,
5 core back, 6 stator core, 7 stator slot, 12 rotor core,
13a Central magnet insertion hole, 13b, 13c Side magnet insertion hole,
14a Central Permanent Magnet, 14b, 14c Side Permanent Magnet,
14b1, 14b2, 14c1, 14c2 Unit side permanent magnets,
15 rotating shaft, 16a inner peripheral side bridge,
16b, 16c outermost peripheral bridge portion, 20a, 20b, 20c gap portion,
21a, 21b, 21c, 22b, 22c, 23b, 23c protrusions,
40 Armature winding

Claims (14)

A stator having a stator core and an armature winding wound around the stator core,
A rotor having a rotor core, a plurality of permanent magnets embedded in the rotor core, and a rotating shaft fixed to the rotor core.
In a rotary electric machine equipped with
The plurality of permanent magnets
A plurality of first permanent magnets having an arcuate cross section that is convex inward in the radial direction of the rotor,
A plurality of second permanent magnets having a rectangular cross section, wherein the rectangular cross section extends from the radial inside to the radial outside of the rotor.
Including
The rotor core is
A plurality of first magnet insertion holes into which the plurality of first permanent magnets are inserted, and
A plurality of second magnet insertion holes into which the plurality of second permanent magnets are inserted, and
Have,
Each of the plurality of magnetic poles of the rotor has one first permanent magnet and two second permanent magnets, the second permanent magnets are arranged on both sides of the first permanent magnet, and the rotation It is configured to be arranged line-symmetrically with respect to the radial direction of the child.
The second magnet insertion hole is a rotary electric machine characterized by having a gap portion at an end portion on the outer side in the radial direction of the rotor. In the rotary electric machine according to claim 1,
The rotor core has a first bridge portion interposed between the outermost outer peripheral surface of the rotor and the gap portion.
The first bridge portion is located along the circumferential direction of the rotor.
The first bridge portion is a rotary electric machine characterized in that the width of the rotor in the radial direction is set to a constant value along the circumferential direction of the rotor. In the rotary electric machine according to claim 2,
The gap is formed in the two inner wall surfaces along the radial direction of the rotor.
The length of one inner wall surface located on the d-axis side, which is the magnetic flux axis of the magnetic pole, is L1, and the length L2 of the other inner wall surface located on the q-axis side orthogonal to the magnetic flux axis in terms of electrical angle. Then, the rotary electric machine characterized in that L1 <L2. In the rotary electric machine according to claim 2 or 3.
A rotary electric machine characterized in that the corner portion of the gap portion in contact with the first bridge portion has an arc shape. In the rotary electric machine according to any one of claims 2 to 4.
A rotating electric machine having a gap portion in which the width of the gap portion in the circumferential direction in contact with the first bridge portion is narrower than the width of the second permanent magnet. In the rotary electric machine according to any one of claims 1 to 5.
A rotary electric machine having voids at the radial inner end of the rotor of the second magnet insertion hole and / or at both ends of the first magnet insertion hole. In the rotary electric machine according to claim 6,
The rotor core has a second bridge portion interposed between the end portion of the first permanent magnet and the end portion of the second permanent magnet inside the rotor in the radial direction. Electric. In the rotary electric machine according to claim 7,
The second bridge portion is a rotary electric machine characterized in that the width of the rotor in the radial direction is set to a constant value between both ends of the rotor in the circumferential direction. In the rotary electric machine according to claim 7 or 8.
The radial inner ends of the rotor of the second magnet insertion hole and / or the corners of the gap at both ends of the first magnet insertion hole in contact with the second bridge are arcuate. A rotating electric machine characterized by that. In the rotary electric machine according to any one of claims 7 to 9.
The radial inner end of the rotor of the second magnet insertion hole and / or the width of the gap at both ends of the first magnet insertion hole in the circumferential direction of the rotor in contact with the second bridge. However, the rotary electric machine is characterized by having a gap portion narrower than the width of the second permanent magnet. In the rotary electric machine according to any one of claims 1 to 10.
Assuming that the distance between the outermost circumference of the rotating shaft and the outer peripheral surface of the arcuate cross section of the first permanent magnet is L3 and the width of the first permanent magnet in the radial direction of the rotor is L4, L4 ≦ L3. A rotating electric machine characterized by being there. In the rotary electric machine according to claim 11,
A rotary electric machine characterized in that L4 ≦ L3 <L5, where L5 is the distance between the inner peripheral surface of the arcuate cross section of the first permanent magnet and the outermost outer peripheral surface of the rotor. In the rotary electric machine according to any one of claims 1 to 12.
The second permanent magnet is a rotary electric machine characterized by being composed of a plurality of permanent magnets. In the rotary electric machine according to any one of claims 1 to 13.
At each of the plurality of magnetic poles, the first permanent magnets, in the radial direction of the rotor, the outermost peripheral surface of the rotor and the radially inner ends of the two second permanent magnets of the rotor. A rotating electric machine characterized by being located between and.

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