JP6127893B2 - Rotor for rotating electrical machines - Google Patents

Description

  The present invention relates to a rotor for a rotating electrical machine including a rotor core having a plurality of magnet holes and a permanent magnet divided into a plurality of magnet holes.

  2. Description of the Related Art Conventionally, in a rotor for a rotating electrical machine, a configuration is known in which a permanent magnet inserted into a magnet hole of a rotor core is divided into a plurality of parts. In this configuration, even when the magnetic flux acting from the stator varies during rotation of the rotor, eddy current loss in the permanent magnet may be suppressed.

  Patent Document 1 describes a rotor for a rotating electrical machine in which two magnets are inserted into each of magnet holes, and a structure that suppresses contact between the two magnets by injecting resin between the magnets. Has been. Suppression of eddy current loss is expected by suppressing contact between magnets.

  Patent Document 2 describes a configuration in which a plurality of magnets are inserted into magnet holes in a rotor for a rotating electrical machine, and a foamed resin sheet or an elastic sheet is sandwiched between the magnets.

JP 2013-165625 A JP 2010-141989

  Even when contact between a plurality of magnets arranged in the magnet hole is suppressed, if each magnet is electrically connected via the rotor core, the eddy current generated in each magnet is short-circuited, resulting in a large eddy current loss. There is a case. In the configuration described in Patent Document 1, when each magnet is covered with a resin, the amount of resin used increases, which is a factor that increases the manufacturing cost. On the other hand, when an insulating film is provided on the entire surface of each magnet arranged by being divided into magnet holes, the amount of the film increases, resulting in an increase in cost. Patent Document 2 does not disclose means for solving such a problem.

  The objective of this invention is providing the rotor for rotary electric machines which can suppress the eddy current loss in a magnet at low cost.

Rotating electric machine rotor according to the present invention includes: a rotor core having a magnet hole provided to extend in the axial direction in the circumferential direction a plurality of locations, wherein each magnet hole, and permanent magnets distributed in a plurality, the A plurality of the permanent magnets in each of the magnet holes include at least a coated magnet having an insulating film provided on a core contact surface that contacts the rotor core, and a non-coated magnet without the insulating film ; The film-coated magnet has the insulating film provided only on the core contact surface .

  The rotor for a rotating electrical machine according to the present invention can suppress eddy current loss in a magnet at low cost.

It is a schematic sectional drawing of the rotary electric machine containing the rotor for rotary electric machines of embodiment which concerns on this invention. It is an enlarged view of the AA cross section of FIG. It is a figure which takes out 2 sets of permanent magnets from FIG. 2, and shows an eddy current path | route. It is a figure corresponding to FIG. 2 in a comparative example. It is a figure corresponding to FIG. 3 in a comparative example. It is a figure corresponding to FIG. 2 which shows the other example of the rotor for rotary electric machines of embodiment which concerns on this invention.

  Embodiments according to the present invention will be described below with reference to the drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like. Hereinafter, the stator core and the rotor core constituting the rotating electrical machine will be described as being formed by laminating electromagnetic steel plates, but this is an example, and a laminate of plate materials other than the electromagnetic steel plates may be used. Other stator cores and rotor cores may be used. For example, instead of a laminated type of plate materials, an integrated core obtained by processing a steel material or a core formed by a green powder compact may be used. In addition, the stator core and the rotor core may be a split core formed by annularly connecting a plurality of elements that are split in the circumferential direction.

  In the following, when a plurality of embodiments and modified examples are included, they can be implemented by appropriately combining them. In the following description, similar elements are denoted by the same reference numerals in all drawings.

  A rotating electrical machine 10 including a rotor for a rotating electrical machine (hereinafter simply referred to as “rotor”) 12 of the present embodiment is a motor having a function of, for example, a motor for driving a hybrid vehicle, a generator, or both. Used as a generator. The rotating electrical machine 10 can also be used as a travel motor for electric vehicles other than hybrid vehicles or fuel cell vehicles.

  FIG. 1 is a schematic cross-sectional view of a rotating electrical machine 10 that includes a rotor 12. FIG. 2 is an enlarged view of the AA cross section of FIG. The rotating electrical machine 10 is, for example, a synchronous motor with a permanent magnet that is driven by a three-phase alternating current. The stator 14 is fixed to the inside of a motor case (not shown), and the stator 14 is radially inward with a predetermined gap. The rotor 12 is disposed so as to face the stator 14 and is rotatable with respect to the stator 14. The “radial direction” is a radial direction orthogonal to the rotation center axis of the rotor 12. The “axial direction” is a direction parallel to the rotation center axis of the rotor 12, and the “circumferential direction” is a direction along a circle drawn around the rotation center axis of the rotor 12. The rotor 12 is fixed to the rotating shaft 16 and rotates integrally with the rotating shaft 16.

  The stator 14 includes a stator core 18, teeth 19 arranged at a plurality of equally spaced positions in the circumferential direction of the stator core 18, and a plurality of phases wound around each tooth 19 (more specifically, u phase, v phase, w phase). 3 phase) stator winding 20. Specifically, a plurality of teeth 19 protruding radially inward (toward the rotor 12) are arranged on the inner peripheral surface of the stator core 18 at intervals from each other along the circumferential direction of the stator 14. Slots 22 (FIG. 2) are formed between the teeth 19. The stator core 18 and the plurality of teeth 19 are integrally formed by a laminated body in which a plurality of electromagnetic steel plates are laminated.

  The stator winding 20 of each phase is wound around the teeth 19 through the slots 22 in a concentrated winding or a distributed winding. In this way, the stator magnetic pole is formed by winding the stator winding 20 around the teeth 19. When a plurality of phases of alternating current flow through the plurality of stator windings 20, a plurality of teeth 19 arranged in the circumferential direction are magnetized, and a rotating magnetic field that rotates in the circumferential direction is generated in the stator 14. The rotating magnetic field formed on the teeth 19 acts on the rotor 12 from the tip surface.

  The rotor 12 includes a rotor core 24 that is a cylindrical rotor yoke, and magnetic poles 26 that are arranged at a plurality of equally spaced locations in the circumferential direction of the rotor core 24. The rotor core 24 is integrally formed by a laminated body in which a plurality of electromagnetic steel plates are laminated in the axial direction. Each magnetic pole 26 is formed including two sets of non-coated magnets 28 and a coated magnet 30 described later, which are permanent magnets arranged in a V-shaped cross section. The rotor core 24 and the plurality of magnets 28 and 30 will be described in detail later.

  The rotating shaft 16 is rotatably supported by a motor case by a bearing (not shown). The rotor 12 is fixed to the outer diameter side of the intermediate portion in the axial direction of the rotating shaft 16 and is disposed opposite to the inner side of the stator 14 in the radial direction with a gap.

  The rotor core 24 includes magnet holes 32 (FIG. 2) provided so as to extend in the axial direction and to penetrate at a plurality of locations in the circumferential direction. A plurality of sets of magnet holes 32 are formed at a plurality of locations in the circumferential direction of the rotor core 24. Each set of the magnet holes 32 is formed in a V-shaped cross section in which a gap is increased toward the outside in the radial direction. In FIG. 2, a set of V-shaped magnet holes 32 are shown, which are similarly arranged at a plurality of locations in the circumferential direction of the rotor 12.

  The plurality of magnets 28, 30 include a non-coated magnet 28 and a coated magnet 30, which are permanent magnets divided into a plurality of magnet holes 32. The magnets 28 and 30 in each magnet hole 32 are divided and arranged in each magnet hole 32 so as to be divided into two in the circumferential direction. In addition, “divided arrangement” means that when one magnet is divided into a plurality of magnets, the plurality of magnets are arranged separately so as to have the same magnetic characteristics as each divided magnet. To do.

  The uncoated magnet 28 and the coated magnet 30 each have a rectangular parallelepiped shape whose cross section perpendicular to the axial direction is a rectangle. In each of the magnets 28 and 30, the radially outer surfaces S1a and S1b and the radially inner surfaces S2a and S2b, which are surfaces formed by the longitudinal sides and the axial sides of the rectangular cross-sectional shape, are the magnetized surfaces. . As will be described later, the magnets 28 and 30 disposed in one magnet hole 32 have the same magnetization direction.

  In the uncoated magnet 28 and the coated magnet 30, the radially outer surfaces S 1 a and S 1 b and the radially inner surfaces S 2 a and S 2 b are core contact surfaces that contact the rotor core 24 on the inner surface of the magnet hole 32.

  The magnet 28 without a film does not have an insulating film on the entire surface, and is a so-called film-less. On the other hand, the coated magnet 30 includes an insulating film 34 provided on a surface including at least the radially outer surface S1b and the radially inner surface S2b. Specifically, the coated magnet 30 includes a radially outer side surface S1b, a radially inner side surface S2b, and both circumferential side surfaces S3, S4, and covers the entire circumferential surface surrounding a rectangular section perpendicular to the axial direction. The insulating film 34 provided is included. Since both end surfaces in the axial direction of the magnet 30 with film are not easily affected by the magnetic field from the stator 14, the insulating film 34 is not provided. Depending on the specifications of the rotating electrical machine, an insulating coating may be provided on the entire surface of the coated magnet 30 including both axial end surfaces.

  The type of magnet forming each of the non-coated magnet 28 and the coated magnet 30 is not limited, and for example, a rare earth magnet, a ferrite magnet, or an alnico magnet can be used. As the rare earth magnet, a ternary neodymium magnet obtained by adding iron and boron to neodymium, a samarium cobalt magnet made of a binary alloy of samarium and cobalt, or a samarium iron nitrogen magnet may be used. Since these magnets have a relatively high conductivity, eddy currents may be generated due to the influence of the magnetic field from the stator 14, which may cause loss.

  The insulating film 34 is provided on the coated magnet 30 in order to suppress loss due to eddy current. As the insulating film 34, a polyimide resin (PA) or a polyamideimide resin (PAI) may be used.

  The uncoated magnet 28 and the coated magnet 30 are inserted and arranged in each magnet hole 32 side by side in the circumferential direction. Preferably, a circumferential gap is provided between the uncoated magnet 28 and the coated magnet 30. You may make it contact mutually without providing a clearance gap between the magnet 28 with a film | membrane, and the magnet 30 with a film | membrane. The reason why the insulating film 34 is provided only on the magnet 30 among the pair of magnets 28 and 30 arranged side by side in the one magnet hole 32 is that eddy currents generated in the two magnets 28 and 30 as described later. This is because the insulating film 34 is not provided on both the two magnets 28 and 30, and the coating cost can be reduced.

  Each magnetic pole 26 is formed by magnets 28 and 30 arranged in a V-shaped cross section, and the two sets of magnets 28 and 30 forming each magnetic pole 26 are magnetized so that the same side has the same magnetic characteristics in the radial direction. Yes. In this case, the magnetizing directions of the pair of magnets 28 and 30 are the same. Magnetic poles 26 adjacent in the circumferential direction have different magnetic characteristics. Thus, the N pole magnetic pole 26 and the S pole magnetic pole are alternately arranged in the circumferential direction on the outer peripheral surface of the rotor 12.

  Two sets of magnets 28 and 30 forming each magnetic pole 26 are symmetrically arranged on both sides with respect to a magnetic pole center line C which is a radial line passing through the center of the magnetic pole in the circumferential direction. The two sets of magnets 28 and 30 may be arranged asymmetrically with respect to the magnetic pole center line C. Moreover, you may comprise the magnet which forms the one magnetic pole 26 only with the some permanent magnet inserted and arrange | positioned at one magnet hole. For example, one magnetic pole may be formed by inserting and arranging the non-coated magnet 28 and the coated magnet 30 in the magnet hole arranged along the circumferential direction of the rotor core 24 along the circumferential direction.

  Further, pocket portions 36 that are extended outward from both circumferential end surfaces of the magnets 28 and 30 are formed at both end portions in the circumferential direction of each magnet hole 32. Insulating molten resin is injected into each pocket portion 36 and solidified to prevent the magnets 28 and 30 from coming out of the magnet hole 32. It is good also as a space | gap part, without pouring resin into each pocket part 36. FIG.

  In a state where the magnets 28 and 30 are disposed in each magnet hole 32, a pair of end plates (not shown) may be disposed on both sides in the axial direction of the rotor core 24, and the rotor core 24 may be sandwiched from both sides in the axial direction by the pair of end plates. .

  According to the rotor 12, since the insulating film 34 is provided between the magnet portion of the coated magnet 30 and the rotor core 24, the coated magnet 30 and the uncoated magnet 28 inserted into one magnet hole 32. The generated eddy current can be prevented from being short-circuited to become a large eddy current. In addition, since the magnets 28 and 30 in each magnet hole 32 include the magnet 28 without a film, it is not necessary to provide the insulating film 34 on all of the magnets 28 and 30 in each magnet hole 32. For this reason, the eddy current loss in the magnets 28 and 30 can be suppressed at low cost.

  The effect of suppressing such eddy current loss will be described in detail with reference to FIGS. FIG. 3 is a diagram showing an eddy current path by taking out two sets of magnets 28 and 30 forming one magnetic pole 26 from FIG. In FIG. 3, the insulating film 34 provided on the coated magnet 30 is indicated by sand.

  As shown in FIGS. 2 and 3, when the rotor 12 operates in an alternating magnetic field included in the rotating magnetic field formed by the stator 14 (FIG. 1) and magnetic fluxes are linked to the magnets 28 and 30, There is a possibility that eddy currents are respectively formed in the magnets 28 and 30 in the direction indicated by the arrow α (FIG. 3) so as to cancel the fluctuation of the magnetic flux. When this eddy current increases, the eddy current loss increases and becomes a factor that increases the heat generation of the magnet.

  In the present embodiment, in the coated magnet 30, the insulating coating 34 is provided on the entire circumferential surface including the radially outer surface S1b and the radially inner surface S2b, which are core contact surfaces, so that each magnet hole 32 (FIG. 2) is provided. The eddy currents between the two magnets 28 and 30 arranged are not short-circuited via the rotor core 24 to become a large eddy current. Further, since the insulating film 34 of the coated magnet 30 is provided between the two magnets 28 and 30, the eddy currents are not short-circuited between the magnets 28 and 30. For this reason, since the eddy current formed in the magnets 28 and 30 is a small one formed by each of the magnets 28 and 30, the eddy current loss is reduced. Furthermore, since it is not necessary to provide the insulating film 34 on the non-coated magnet 28 among the magnets 28 and 30 arranged in each magnet hole 32, the cost of the rotor 12 can be reduced by reducing the amount of the coated film.

  FIG. 4 is a diagram corresponding to FIG. 2 in the comparative example, and FIG. 5 is a diagram corresponding to FIG. 3 in the comparative example. In the comparative example shown in FIGS. 4 and 5, two uncoated magnets 28 are inserted and arranged in each magnet hole 32 (FIG. 2). An insulating film is not provided on each surface of the non-coated magnet 28. Other configurations are the same as those in FIGS. 1 to 3.

  In such a comparative example, when the rotor 12 operates in an alternating magnetic field included in the rotating magnetic field formed by the stator 14 (FIG. 2) and the magnetic flux is linked to each magnet 28, the fluctuation of the magnetic flux is canceled out. Thus, an eddy current may be formed in the magnet 28 in the direction indicated by the arrow β. In this case, even if a gap is formed between the two magnets 28 arranged in one magnet hole 32 and the magnets 28 are insulated, the eddy current generated in the two magnets 28 is generated by the rotor core 24. Are short-circuited by an electrical short-circuit path 37 formed into a large loop eddy current. In this case, the eddy current loss is increased and the heat generation of the magnet 28 is increased. In this case, when the two non-coated magnets 28 are separately arranged, the eddy currents in the two magnets 28 are short-circuited by the rotor core 24, so that the effect of reducing the eddy current loss due to the division cannot be obtained. There is a possibility that such an inconvenience can be solved by providing insulating films on all the magnets, but in this case, the cost increases. Such an inconvenience can be eliminated in the present embodiment.

  FIG. 6 is a view corresponding to FIG. 2 showing another example of the rotor 12 according to the embodiment of the present invention. In the rotor 12 of this example, a gap 40 is provided between the non-coated magnet 28 and the coated magnet 38 that are separately arranged in each magnet hole 32, and the uncoated magnet 28 and the coated magnet 30 are directly connected to each other. Not touching. Further, the coated magnet 30 is provided with the insulating coating 34 only on the radially outer side surface S1b and the radially inner side surface S2b, which are the two core contact surfaces. In order to provide the gap 40 between the non-coated magnet 28 and the coated magnet 38, conditions for resin injection into the pocket portion 36, for example, one or both of the resin injection speed and the resin temperature may be controlled. Further, a convex portion that protrudes inward of the magnet hole 32 is formed in a portion where the gap 40 is provided, and the gap 40 is formed by restricting the displacement of the non-coated magnet 28 and the coated magnet 38 in a direction approaching each other. May be. In the magnet hole 32, if the longitudinal side of the rectangular section other than the pocket portion 36 is larger than the sum of the longitudinal sides of the rectangular sections of the two magnets 28 and 38, the gap 40 is formed accordingly. There is also a case.

  In the case of the configuration of this example as well, the eddy current loss in the magnets 28 and 38 can be suppressed at a low cost, similarly to the configurations of FIGS. Furthermore, since the amount of the insulating film 34 of the coated magnet 30 can be reduced as compared with the case of the configuration of FIGS. 1 to 3, the coating cost can be further reduced. Other configurations and operations are the same as those in FIGS. 1 to 3.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, In the range which does not deviate from the summary of this invention, it can implement with a various form. Of course. For example, in the above description, the case where a total of two magnets, that is, the coated magnet 30 (or 38) and the uncoated magnet 28 are inserted and arranged in one magnet hole 32, is described. The number of permanent magnets arranged in one magnet hole may be three or more. Moreover, although the permanent magnet arrange | positioned at one magnet hole was used as the permanent magnet divided | segmented into multiple in the circumferential direction in the above, it is good also as a permanent magnet divided into multiple in the axial direction or radial direction. In addition, in the permanent magnet in each magnet hole, it is sufficient that an insulating film or a gap is provided between a magnet with a coating having an insulating film provided on at least a core contact surface and a magnet without a film, and the above-described implementation It is not limited to the form.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Rotor, 14 Stator, 16 Rotating shaft, 18 Stator core, 19 Teeth, 20 Stator winding, 22 Slot, 24 Rotor core, 26 Magnetic pole, 28 Magnet without coating, 30 Magnet with coating, 32 Magnet hole, 34 Insulation Film, 36 pocket part, 37 short circuit, 38 magnet with film, 40 gap.

Claims (2)

A rotor core having magnet holes provided to extend in the axial direction at a plurality of locations in the circumferential direction;
Wherein each magnet hole, comprising a permanent magnet are distributed in a plurality, and
The plurality of permanent magnets in each of the magnet holes includes a coated magnet having an insulating film provided on at least a core contact surface that contacts the rotor core, and a non-coated magnet having no insulating film ,
The magnet with a film is a rotor for a rotating electrical machine having the insulating film provided only on the core contact surface . The rotor for a rotating electrical machine according to claim 1 ,
A rotor for a rotating electrical machine, wherein a gap is provided between the coated magnet and the uncoated magnet in the plurality of permanent magnets in each magnet hole.

Images