JP2019075930A - Rotor for rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve a stress based on a difference in linear expansion coefficient between a rotor core and an end plate in a bridge portion in a rotor of a rotary electric machine. SOLUTION: A rotor 10 of a rotary electric machine has a magnetic rotor core 12 in which a magnet insertion hole 30 into which a permanent magnet 40 forming a magnetic pole is inserted is arranged along the circumferential direction, and an axial end portion of the rotor core 12. It includes fixed non-magnetic end plates 14 and 15. The rotor core 12 has a pair of magnet insertion holes that are arranged line-symmetrically with respect to the magnetic pole center line at each of the magnetic poles and form a bridge portion in close proximity to the magnetic pole center line. The end plates 14 and 15 include a slit 50 which is a stress relaxation hole provided in the vicinity of the bridge portion in the rotor core 12 and at a position not overlapping with the magnet insertion hole. [Selection diagram] Fig. 1

Description

  The present disclosure relates to a rotor of a rotating electrical machine, and more particularly to a rotor of an embedded magnet type rotating electrical machine.

  The rotor core of the interior permanent magnet (IPM) rotary electric machine forms a laminated body in which a plurality of magnetic thin plates provided with magnet insertion holes for arranging permanent magnets are laminated, and each magnet insertion hole Permanent magnets are inserted and embedded. In the case of a permanent magnet having a rectangular cross section, the magnet insertion hole is a rectangular hole larger than the permanent magnet, but both ends of the rectangular hole are extended to narrow the magnetic path between adjacent magnet insertion holes. Formation and suppression of magnetic flux leakage between adjacent permanent magnets are performed.

  Further, nonmagnetic end plates are provided on both sides in the axial direction of the rotor core so that the permanent magnet does not protrude from the magnet insertion hole when the rotor rotates. When the rotor core is a laminate of thin magnetic sheets, the end plate also has a function of pressing the thin laminate in the axial direction.

  In Patent Document 1, as a rotor of an IPM electric rotating machine, an end plate for fixing a permanent magnet and a rotor core is disposed at an end of the rotor core, and the end plate has a claw portion bent at its outer shell, and the claw portion Discloses a configuration in which a portion of the side surface of the rotor core is pressed.

JP, 2011-004529, A

  The rotor core is a magnetic body, and the end plates are nonmagnetic, so the materials are different from each other, and the linear expansion coefficients are different. When the rotor core and the end plate are fixed to each other at a plurality of junctions, when the temperature environment changes, the difference between the linear expansion coefficients causes one of the rotor core and the end plate to relatively extend, and the other relatively. to shrink. When the rotor core expands or contracts between the joints, a larger stress is generated in the bridge portion where the magnetic portion of the rotor core is the narrowest than other portions. If excessive stress is generated in the bridge portion, it may affect the torque characteristics of the rotating electrical machine and possibly lead to breakage of the rotor. Then, when the stress based on the difference of a linear expansion coefficient arises in a bridge part, the rotor of the rotation electrical machinery which can relieve the stress is demanded.

  A rotor of a rotating electrical machine according to the present disclosure is provided fixed to an axial end portion of a rotor core of a magnetic body in which magnet insertion holes into which permanent magnets forming magnetic poles are inserted are arranged along the circumferential direction. And a nonmagnetic end plate, wherein the rotor core is disposed in line symmetry with respect to the pole centerline at each of the magnetic poles, and a pair of magnet insertion holes forming bridge portions close to each other with respect to the pole centerline The end plate includes a stress relief hole provided in the vicinity of the bridge portion in the rotor core and in a position not overlapping the magnet insertion hole in the axial direction.

  According to the above configuration, the end plate includes the stress relieving hole in the vicinity of the portion corresponding to the bridge portion in the rotor core in the axial direction. As a result, with respect to the extension or reduction deformation that occurs in the end plate due to the difference in linear expansion coefficient when the temperature environment of the rotor changes, the deformation in the vicinity of the bridge portion of the rotor core can be absorbed in axial view. Corresponding to this, the deformation in the vicinity of the bridge portion of the rotor core is suppressed, and the stress generated in the bridge portion can be suppressed. Further, since the stress relieving holes are provided at positions not overlapping with the magnet insertion holes of the rotor core in the axial direction view, the function of the end plate for preventing the projection of the permanent magnet is not impaired.

  According to the rotor of the rotating electrical machine having the above configuration, when a stress based on the difference in linear expansion coefficient is generated in the bridge portion, the stress can be relieved.

It is a perspective view which fractures and shows a part of end plate about a rotor of rotation electrical machinery concerning an embodiment. It is a top view of the rotor core of FIG. It is a figure which extracts and shows the part corresponding to A section of Drawing 2 about a rotor core and an end plate. Fig.3 (a) is a figure which shows the A part of a rotor core, (b) is a figure which shows the part of the end plate corresponding to A part. It is a figure which piles up FIG. 3 by an axial view, and shows it. It is a figure which shows the example of another end plate using the figure corresponding to FIG.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. Hereinafter, although a laminated body of magnetic thin plates is described as a rotor core, this is an example for explanation, and it is an integral type rotor core as long as it is a magnetic body in which a permanent magnet is embedded and a bridge portion can be formed. Good. Moreover, although nonmagnetic stainless steel (SUS) is described as an end plate below, this is an illustration for description, Comprising: If it uses a nonmagnetic material from which a rotor core and a linear expansion coefficient differ, this indication will be this indication. The invention is applied. For example, it may be an end plate of a nonmagnetic metal material such as aluminum or copper, or an end plate of a resin material having an appropriate strength.

  The shape, the material, the number of holes, the number of magnetic poles, and the like described below are examples for the purpose of description, and can be appropriately changed according to the specification of the rotor of the rotating electrical machine and the like. Further, in the following, the same reference numeral is given to the same element in all the drawings, and the overlapping description is omitted.

  FIG. 1 is a perspective view of a rotor 10 of a rotating electrical machine used for a rotating electrical machine mounted on a vehicle. Hereinafter, the rotor 10 of the rotating electrical machine is referred to as the rotor 10 unless otherwise specified. The rotating electrical machine in which the rotor 10 is used is a three-phase synchronous rotating electrical machine, which functions as an electric motor when the vehicle is in a power running mode and as a generator when the vehicle is in braking. The rotary electric machine includes a rotor 10 and an annular stator (not shown) arranged at a predetermined interval on the outer peripheral side of the rotor 10 and on which a winding coil is wound.

  The rotor 10 includes an annular rotor core 12 and disc-shaped end plates 14 and 15. The end plates 14 and 15 are respectively disposed at both axial end portions of the rotor core 12 and are fixed to the rotor core 12 at joint portions 16 and 17 to form an integrated rotor 10. Welding is used to form the joints 16 and 17. Instead of welding, integrated joining means such as caulking, locking by means of claws or the like may be used. At the time of integration, the center hole of the annular rotor core 12 and the center hole of the disk-shaped end plates 14 and 15 are aligned and become a center hole 18 penetrating the integrated rotor 10. A rotor shaft, which is an output shaft of the rotary electric machine, is fixed to the central hole 18 of the rotor 10.

  FIG. 1 shows the central axis CL of the central hole 18, the axial direction and the radial direction. The axial direction is a direction along the central axis CL. When the axial direction is to be distinguished, the end plate 14 side is called one side, and the end plate 15 side is called the other side. The radial direction is a direction pointing to the inner peripheral side and the outer peripheral side of the rotor core 12. In FIG. 1, a part of the end plate 14 is broken to show an end surface 13 on one side of the rotor core 12. In the rotor core 12, a plurality of magnet insertion holes 30 and a plurality of permanent magnets 40 respectively inserted into the respective magnet insertion holes 30 are disposed. The end plate 14 is provided with a plurality of slits 50 as holes for stress relaxation.

  The rotor core 12 is formed by embedding a plurality of permanent magnets 40 in a laminate in which a predetermined number of thin magnetic plates 20 are stacked in the axial direction. The reason why the rotor core 12 is formed of a laminate of the magnetic thin plates 20 is to suppress an eddy current that may occur in the rotor core 12, and insulating coats and the like are formed on both sides of the magnetic thin plate 20 before being formed into a predetermined shape. Insulation treatment is applied. As a result, the laminated magnetic thin plates 20 are electrically insulated, and the eddy current that may be generated by the external variable magnetic field is divided into small loops, and the eddy current loss is suppressed. The magnetic thin plate 20 includes a central hole 18 through which the rotor shaft passes and a plurality of magnet insertion holes 30, and has an annular shape shaped into a predetermined shape. An electromagnetic steel sheet is used as the magnetic thin plate 20. The rotor core 12 may be made of an integrated magnetic body having a plurality of magnet insertion holes 30 instead of the laminate of the magnetic thin plates 20.

  FIG. 2 is a top view of the rotor core 12 in each of the magnetic thin plates 20 in the end face 13 on one side of the rotor core 12 in the axial direction, in the magnet insertion holes 30 provided in the magnetic thin plate 20. It is also a plan view in a state in which the permanent magnet 40 is disposed. The rotor core 12 has eight magnetic poles P, and includes two permanent magnets 40 per magnetic pole P. In FIG. 2, eight magnetic poles P are distinguished and denoted as P1 to P8. Thus, the rotor core 12 includes sixteen magnet insertion holes 30 and sixteen permanent magnets 40. The number of magnetic poles P and the number of permanent magnets 40 per magnetic pole P are examples and can be changed according to the specifications of the rotor 10 and the rotor core 12. The state before the permanent magnet 40 is arrange | positioned is shown to the magnetic pole P5 of FIG. The case where all the eight magnetic poles P are in the state of P5 corresponds to the plan view of the magnetic thin plate 20.

  Since each magnetic pole P has the same configuration, the magnetic pole P1 surrounded by a thick frame indicated by a dashed dotted line in FIG. 2 will be described. The magnetic pole P1 has a pair of magnet insertion holes 60 and 62 as the magnet insertion holes 30, and has a pair of permanent magnets 70 and 72 as the permanent magnet 40. The permanent magnet 70 is inserted into the magnet insertion hole 60, and the permanent magnet 72 is inserted into the magnet insertion hole 62.

  The pair of magnet insertion holes 60 and 62 are arranged in line symmetry with respect to the magnetic pole center line CP of the magnetic pole P1, respectively, and the distance between them spreads toward the outer periphery of the rotor core 12, Are arranged in a V-shape.

  The pair of magnet insertion holes 60, 62 has a hole width slightly larger than the short side dimension of the permanent magnet 70, 72 to be inserted and a longitudinal dimension slightly longer than the long side of the permanent magnet 70, 72 in the plan view. It is a hole which penetrates in the axial direction in the rotor core 12. In the longitudinal direction of the magnet insertion holes 60 and 62, the end portions further extend from both ends of the long sides of the permanent magnets 70 and 72. The end of the magnet insertion hole 60 and the end of the magnet insertion hole 62 facing each other across the magnetic pole center line CP of the magnetic pole P1 are set to a shape that forms a bridge portion 80 for restricting the flow of magnetic flux in the rotor core 12 Be done. The pole center line CP passes through the position of the bridge portion 80 between the magnet insertion hole 60 and the magnet insertion hole 62.

  The permanent magnets 70 and 72 are rectangular bar magnets inserted in magnet insertion holes 60 and 62 penetrating in the axial direction of the rotor core 12. The axial length is slightly shorter than the axial length of the rotor core 12, and the cross-sectional shape perpendicular to the axial direction is a rectangle sized to be inserted into the magnet insertion holes 60 and 62. As materials for the permanent magnets 70 and 72, rare earth magnets such as neodymium magnets mainly composed of neodymium, iron and boron, samarium cobalt magnets mainly composed of samarium and cobalt are used. Other than this, a ferrite magnet, an alnico magnet or the like may be used.

  A resin is used to fix the permanent magnets 70, 72 inside the magnet insertion holes 60, 62. For injection of the fixing resin into the magnet insertion holes 60 and 62, end portions further extending from both ends of the long sides of the permanent magnets 70 and 72 in the longitudinal direction of the magnet insertion holes 60 and 62 are used. As a resin for fixing the permanent magnets 70 and 72, a thermosetting resin excellent in moldability and heat resistance is used. An epoxy resin, a polyimide resin, etc. are used as a thermosetting resin.

  Returning to FIG. 1, the end plates 14 and 15 are made of nonmagnetic stainless steel provided on both axial sides of the rotor core 12 so that the permanent magnet 40 does not protrude from the magnet insertion hole 30 when the rotor 10 rotates. The annular disc with a central hole 18 of In addition to the central hole 18, the end plates 14, 15 are provided with slits 50 as holes for stress relaxation. In the slit 50 as a hole for stress relaxation, when the environmental temperature of the rotor 10 changes, stress is generated in the bridge portion 80 due to the difference between the linear expansion coefficient of the rotor core 12 and the linear expansion coefficient of the end plates 14 and 15 In some cases, it is provided to absorb and relieve the stress. The slits 50 are provided in each of the end plates 14, 15, penetrate in the thickness direction of the end plates 14, 15, and open at the axial end surface of the rotor core 12. The slits 50 are disposed at positions that do not impair the function of the permanent magnets 70 and 72 to prevent popping out and that are suitable for absorption and relaxation of stress generated in the bridge portion 80.

  The arrangement of the stress relaxation slits 50 will be described with reference to FIGS. 3 and 4. Since the end plate 15 has the same structure as the end plate 14, the end plate 14 will be described below unless otherwise specified.

  FIG. 3 is a diagram showing a portion corresponding to the portion A of FIG. 2 with respect to the rotor core 12 and the end plate 14. FIG. 3A is a view showing a portion A of the rotor core 12, and FIG. 3B is a view showing a portion of the end plate 14 corresponding to the portion A. As shown in FIG. In these figures, the respective joints 16 at the rotor core 12 and the end plate 14 are shown. Junction 16 is provided on magnetic pole center line CP. Due to this arrangement, when there is a change in the temperature environment of the rotor 10, tensile or compressive deformation occurring in the rotor core 12 and the end plate 14 and stress distribution associated therewith become symmetrical with respect to the magnetic pole center line CP without deviation. .

  The slits 50 for stress relaxation in the end plate 14 are disposed in the vicinity of a position corresponding to the bridge portion 80 of the rotor core 12 on the pole center line CP passing through the bridge portion 80 between the magnet insertion hole 60 and the magnet insertion hole 62. Be done. The slits 50 of the end plate 14 are disposed in the vicinity of the portion corresponding to the bridge portion 80 of the rotor core 12 for the following reason. That is, when the rotor core 12 and the end plate 14 are fixed to each other at a plurality of joint portions 16 in the rotor 10, when the temperature environment changes, one of the rotor core 12 and the end plate 14 is relative due to the difference in linear expansion coefficient. And the other shrinks relatively. When the rotor core 12 expands or contracts between the joint portions 16, a larger stress is generated in the bridge portion 80 where the magnetic portion of the rotor core 12 is the narrowest as compared with other portions. The slits 50 can absorb the expansion or contraction of the end plate 14 caused by the difference in linear expansion coefficient when the temperature environment of the rotor 10 changes. In the end plate 14, by arranging the slits 50 in the vicinity of the portion corresponding to the bridge portion 80 in the rotor core 12, the deformation in the vicinity of the portion corresponding to the bridge portion 80 of the rotor core 12 can be absorbed in the end plate 14. Corresponding to this, the deformation in the vicinity of the bridge portion 80 of the rotor core 12 is suppressed, and the stress generated in the bridge portion 80 is suppressed. Since the direction of stress that may cause the bridge portion 80 to deform or break is perpendicular to the pole center line CP, the slits 50 extend in the direction perpendicular to the pole center line CP, preferably, the pole center line CP It is preferable to extend in line symmetry with respect to.

  When the slits 50 of the end plate 14 are disposed in the vicinity of the bridge portion 80 of the rotor core 12 in the axial direction view, the permanent magnet of the end plate 14 is located at a position immediately above the magnet insertion holes 60 and 62. 70, 72 pop out prevention function becomes insufficient. Therefore, the slits 50 are disposed avoiding the positions directly above the magnet insertion holes 60 and 62.

  FIG. 4 is a view of a portion of the end plate 14 corresponding to the portion A superimposed on the portion A of the rotor core 12 and viewed in the axial direction from the upper side. This corresponds to a view of the rotor 10 of FIG. 1 viewed from one side in the axial direction without breaking the end plate 14. Since the portion A of the rotor core 12 is hidden behind the end plate 14 and can not be visually recognized, the magnet insertion holes 60 and 62 are indicated by broken lines. As shown in FIG. 4, when viewed in the axial direction of the rotor 10, the slits 50 are on the magnetic pole center line CP and in positions near the bridge portion 80 and not overlapping the magnet insertion holes 60 and 62. Provided. By this arrangement, if stress is generated in the bridge portion 80 due to the difference between the linear expansion coefficients of the rotor core 12 and the end plate 14 without impairing the function of the permanent magnet 70, 72 of the end plate 14 from coming out It can be relaxed.

  In the above, the slits 50 are used as holes for stress relaxation. Instead of the slits 50, circular through holes or oval through holes of appropriate size may be used. In addition, although the slits 50 are disposed on the magnetic pole center line CP, the slits 50 may be an even number of holes or slits symmetrically disposed with the magnetic pole center line CP in between. In addition, although the slits 50 are arranged on the outer peripheral side in the radial direction with respect to the magnet insertion holes 60 and 62, the slits 50 may be arranged on the inner peripheral side in the radial direction as long as they correspond to the vicinity of the bridge portion 80 . Moreover, you may arrange | position combining these. In any of these cases, when the end plate 14 and the rotor core 12 are overlapped and viewed in the axial direction, the stress relaxation holes are disposed at positions not overlapping the magnet insertion holes 60 and 62.

  FIG. 5 shows an example of a stress relief hole other than the slit 50 described in FIG. 3 and FIG. Each drawing of FIG. 5 corresponds to FIG. 4 and is a view showing the case where the end plate 14 and the rotor core 12 are overlapped and viewed in the axial direction. FIG. 5A shows an example using an oval hole 52. (B) is an example which arrange | positions the oblong hole 54 in the inner peripheral side rather than the magnet insertion holes 60 and 62. As shown in FIG. (C) is an example which arrange | positions two circular holes 56 and 57 by the arrangement relation of line symmetry with respect to the magnetic pole centerline CP. Also by these, the same effect as the slit 50 described in FIG. 3 and FIG. 4 is exhibited.

  According to the rotor 10 of the rotating electric machine configured as described above, the end plates 14 and 15 are provided in the vicinity of the bridge portion 80 in the rotor core 12 and in a position not overlapping the magnet insertion holes 60 and 62 in the axial direction. Includes stress relief holes. When the stress is generated in the bridge portion 80 of the rotor core 12 due to the difference between the linear expansion coefficients of the rotor core 12 and the end plates 14 and 15 without impairing the function of the end plates 14 and 15 for preventing the permanent magnet 40 from jumping out by this arrangement. The stress can be relieved. As an effect of stress relaxation of the bridge portion 80, stabilization of torque characteristics of the rotating electrical machine and prevention of breakage of the rotor 10 can be achieved, and furthermore, it becomes possible to make the bridge portion 80 thinner, thereby improving torque characteristics of the rotating electrical machine. Can.

  DESCRIPTION OF SYMBOLS 10 Rotor (of a rotating electrical machine), 12 rotor core, 13 one end face, 14, 15 end plate, 16, 17 joint portion, 18 center hole, 20 magnetic thin plate, 30, 60, 62 magnet insertion hole, 40, 70 , 72 permanent magnets, 50 slits (stress relief holes), 52, 54 oblong holes (stress relief holes), 56, 57 circular holes (stress relief holes), 80 bridge part.

Claims (1)

A rotor core of a magnetic body in which a magnet insertion hole in which a permanent magnet forming a magnetic pole is inserted is disposed along a circumferential direction;
A nonmagnetic end plate fixedly provided at an axial end of the rotor core;
Equipped with
The rotor core is
Each of the magnetic poles is disposed in line symmetry with respect to the magnetic pole center line, and has a pair of the magnet insertion holes forming bridge portions close to each other with respect to the magnetic pole center line,
The end plate is
A rotor of a rotating electrical machine, including a stress relief hole provided in the vicinity of the bridge portion in the rotor core in an axial direction view and not overlapping the magnet insertion hole.

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