JP2013126311A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine which effectively cools magnets of a rotor.SOLUTION: A rotary electric machine 10 includes a rotor 12 and a stator. The rotor 12 includes: a rotor core 22 formed by laminating multiple steel plates 40 in the axial direction; the rotor core 22 where at least the steel plate 40e at the outermost position in the axial end part, from among the multiple steel plates 40, is fastened to the adjacent steel plate 40 by welding or bonding; multiple magnets 30 respectively inserted into multiple magnet holes 23 which penetrate through the rotor core 22 in the axial direction with end surfaces thereof exposed to the exterior; and a coolant passage 32 provided at an inner peripheral side position relative to the multiple magnets 30 and penetrating through the rotor core 22 in the axial direction.

Description

  The present invention relates to a rotating electrical machine, and more particularly to a cooling structure for a rotor and a stator provided in the rotating electrical machine.

  Conventionally, many techniques for cooling a rotating electrical machine have been proposed. For example, in Patent Document 1, by forming a refrigerant passage through which a refrigerant passes inside the rotor core and flowing the refrigerant in the refrigerant passage, the rotor core, a magnet disposed near the outer periphery of the rotor core, A technique for cooling a stator or the like disposed around the outer periphery of the rotor is disclosed. In Patent Document 1, in order to solve the problem that the refrigerant flowing in the rotor core flows between the electromagnetic steel sheets when the rotor core is composed of laminated electromagnetic steel sheets, the outer peripheral surface of the refrigerant flow path is covered. A resin mold is provided. According to this technique, it is possible to efficiently cool to some extent while suppressing the occurrence of energy loss.

International Publication No. 2011/045860 Pamphlet

  However, in the prior art including this Patent Document 1, sufficient consideration is not given to the flow of the refrigerant discharged from the rotor core, and it is difficult to say that the cooling efficiency is high. In particular, in the prior art, the end face of the magnet embedded in the rotor core is covered with an end plate or the like, and heat exchange with the refrigerant discharged from the refrigerant flow path has not been sufficiently performed.

  Therefore, an object of the present invention is to provide a rotating electrical machine that can cool a rotor magnet more efficiently than in the prior art.

  A rotating electrical machine according to the present invention is a rotating electrical machine including a rotor that rotates about an axis and a stator that is disposed on the outer periphery of the rotor. The rotor includes a plurality of steel plates stacked in an axial direction. The rotor core, wherein the steel plate located at least at the end in the axial direction among the plurality of steel plates is fixed to another steel plate adjacent by welding or adhesion, and the end face thereof is exposed to the outside, A plurality of magnets that are inserted through a plurality of magnet holes that penetrate the rotor core in the axial direction; and a refrigerant flow path that is provided at an inner peripheral side of the plurality of magnets and penetrates the rotor core in the axial direction. Features.

  In a preferred aspect, a guide portion for guiding the refrigerant discharged from the end portion of the refrigerant flow path to the vicinity of the end portion of the magnet is formed on the end face of the rotor core. In this case, it is desirable that the guide portion is formed of a weld bead.

  In another preferred aspect, the rotor further includes a resin mold portion that covers at least the outer periphery of the rotor core. In this case, the resin mold portion includes a mold end portion that covers an outer peripheral side portion of the rotor core in the axial end surface of the rotor core, and the mold end portion is directed outward in the axial direction as approaching the radially outer side. It is desirable to be inclined. It is also desirable that the resin mold part is made of a resin containing a magnetic material.

  According to the present invention, at least the steel plate located at the end in the axial direction is fixed to another adjacent steel plate by a strong fixing means such as welding or adhesion. The bonded state of the steel plates can be maintained. Since there is no end plate, the end face of the magnet can be exposed to the outside, and as a result, the rotor magnet can be cooled more efficiently.

It is sectional drawing which shows schematic structure of the rotary electric machine which is embodiment of this invention. It is a schematic front view of a rotor. It is a general | schematic enlarged view of the edge part periphery of a rotor. It is sectional drawing which shows schematic structure of the conventional rotary electric machine.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a rotating electrical machine 10 according to an embodiment of the present invention. FIG. 2 is a schematic front view of the rotor 12 of the rotating electrical machine 10.

  The rotating electrical machine 10 described here is a motor and / or generator, and is typically mounted on a hybrid vehicle, but its application is not limited to a hybrid vehicle, such as a fuel cell vehicle, an electric vehicle, and the like. You may mount in an electric equipment.

  The rotating electrical machine 10 is roughly divided into a rotor 12 and a stator 14. The stator 14 includes a ring-shaped stator core 16 and a stator coil 20. The stator core 16 is composed of an electromagnetic steel plate or a dust core made of iron or an iron alloy. A plurality of teeth portions and slot portions as recesses formed between the teeth portions are formed on the inner peripheral surface of the stator core 16, and each slot portion is provided so as to open to the inner peripheral side of the stator core 16. It is done.

  Stator coil 20 including three winding phases, U phase, V phase, and W phase, is wound around the tooth portion so as to fit into the slot portion. The U phase, the V phase, and the W phase are wound so as to deviate from each other on the circumference. The U phase, the V phase, and the W phase may be wound around a single tooth portion that is different from each other, or may be wound around a plurality of tooth portions so that some of them overlap each other. Good. In any case, a part of the stator coil wound around the tooth portion protrudes outward from the end face of the stator core to form the coil end 21.

  The rotor 12 is disposed concentrically with the stator 14 and includes a rotor shaft 24 serving as a rotation shaft, a rotor core 22 fixed to the rotor shaft 24, a permanent magnet 30 inserted through the rotor core 22, and the like. The rotor core 22 is configured by laminating a plurality of electromagnetic steel plates in the axial direction. Near the outer periphery of the rotor core 22, a plurality of magnet holes 23 extending in the axial direction are formed side by side in the circumferential direction as shown in FIG. Permanent magnets 30 serving as magnetic poles of the rotor 12 are inserted through the magnet holes 23. In addition, the arrangement | positioning aspect of the permanent magnet 30 shown in FIG. 2 is an example, The number, shape, arrangement | positioning angle, and arrangement position may be changed suitably.

  Further, in the rotor core 22, a refrigerant flow path 32 through which a refrigerant flows is formed on the inner peripheral side of the permanent magnet 30. The refrigerant flow path 32 is a hole that penetrates the rotor core 22 in the axial direction. As shown in FIG. 2, a plurality of refrigerant flow paths 32 are arranged in the circumferential direction. Note that the arrangement mode of the refrigerant flow path 32 shown in FIG. 2 is an example. If the refrigerant flow path 32 is arranged on the inner peripheral side from the permanent magnet 30, the number, shape, arrangement angle, and arrangement position are appropriately changed. Good. However, in order to cool the rotor 12 and the stator 14 evenly, it is desirable that the refrigerant flow paths 32 be evenly arranged in the circumferential direction.

  The rotor shaft 24 is rotatably attached to a case (not shown) of the rotating electrical machine 10 via a bearing portion (not shown). The rotor shaft 24 is fixed to the rotor core 22 and rotates together with the rotor core 22. A hollow portion 34 through which the refrigerant passes is formed inside the rotor shaft 24. At least a part of the refrigerant flowing through the hollow portion 34 is guided to the refrigerant flow path 32 formed in the rotor core 22 via the communication path 36 connecting the hollow portion 34 and the refrigerant flow path 32.

  In the present embodiment, in order to further improve the cooling efficiency by the refrigerant guided to the refrigerant flow path 32, the rotor core 22 and the like have a special configuration. This will be described in comparison with the prior art.

  FIG. 4 is a schematic sectional view showing a schematic configuration of a conventional rotating electrical machine. Even in a conventional rotating electrical machine, the rotor core 22 is configured by laminating a plurality of electromagnetic steel plates in the axial direction. In the conventional rotor, the magnetic steel sheet is connected to a bump that presses the convex formed on the back surface thereof into the concave formed on the surface of another adjacent magnetic steel sheet. Such a caulking bond has a problem that the bonding effort is easy, while the bonding force is relatively poor. Therefore, in a conventional rotating electrical machine, a laminated body of electromagnetic steel plates that are caulked and joined is sandwiched between a pair of end plates 50. The end plate 50 is fixed to the rotor shaft 24, and its axial position is regulated. By being sandwiched by the end plate 50, the plurality of electromagnetic steel sheets are kept in close contact with each other, and peeling of the electromagnetic steel sheets is prevented.

  The flow of the refrigerant in the conventional rotating electrical machine 10 is as shown by a broken line in FIG. That is, a discharge hole 52 is provided in the end plate 50 at a position corresponding to the refrigerant flow path 32 formed in the rotor core 22 (laminated body). The refrigerant supplied to the hollow portion 34 of the rotor shaft 24 passes through the communication path 36 and the refrigerant flow path 32 and is then discharged to the outside from the discharge hole 52. The discharged refrigerant is carried outward in the axial direction by the centrifugal force generated with the rotation of the rotor 12, hits the coil end 21 and the like of the stator 14, and cools them. Thereafter, the refrigerant that has fallen to the bottom of the case of the rotating electrical machine 10 due to gravity is pumped up by a pump (not shown), and is supplied again to each part of the rotating electrical machine 10 as a coolant.

  Here, in the case of such a conventional rotating electrical machine 10, the coil end 21 can be efficiently cooled, but it is difficult to efficiently cool the permanent magnet 30 disposed on the rotor 12. That is, in the conventional rotor 12, both ends of the rotor core 22 (laminated body of electromagnetic steel plates) are sandwiched between the end plates 50, and the end surfaces of the permanent magnets 30 are covered with the end plates 50. Therefore, although the refrigerant discharged from the discharge hole 52 flows on the surface of the end plate 50, it cannot directly contact the permanent magnet 30, and heat cannot be efficiently removed from the permanent magnet 30. . As a result, the permanent magnet 30 could not be efficiently cooled, causing problems such as thermal demagnetization of the permanent magnet 30 due to heat generation, and consequently reduction in efficiency of the rotating electrical machine 10.

  Therefore, in this embodiment, in order to cool the permanent magnet 30 more efficiently, the rotor 12 has a special configuration, thereby eliminating the need for the end plate 50 and enabling the permanent magnet 30 to be efficiently cooled. . This will be described with reference to FIG. FIG. 3 is a schematic enlarged view around the end of the rotor core 22.

  As described above, the end plate 50 hinders cooling of the permanent magnet 30. Thus, although it is conceivable to omit the end plate 50, simply omitting the end plate 50 cannot maintain the connected state of the electromagnetic steel sheets 40, and some of the electromagnetic steel sheets 40 may be peeled off. In particular, the electromagnetic steel sheet 40e located at the end most has a problem that it is relatively easy to peel off. Therefore, in the present embodiment, at least for the electrical steel sheet 40e located at the end, instead of caulking, or in addition to caulking, a joining method called welding is adopted, and the electrical steel sheet located at the end. 40e is fixed to another adjacent electromagnetic steel sheet 40 by welding. As already described, the electromagnetic steel sheet 40e located at the end is the electromagnetic steel sheet that is most easily peeled off. The electromagnetic steel sheet 40e can be effectively prevented from being peeled off by fixing the electromagnetic steel sheet 40e located at the end to the other adjacent electromagnetic steel sheet 40 by a strong fixing means called welding. In FIG. 3, the bold line portion indicates the welding location. As is apparent from FIG. 3, in this embodiment, the electromagnetic steel plates 40 other than the end electromagnetic steel plates 40 e are replaced with the caulking portions 38 that are uneven portions as the caulking portions 38 of the adjacent electromagnetic steel plates 40, as in the prior art. It is connected with a squeeze that can be pushed in. Thus, about the electromagnetic steel plate 40 other than an edge part, the manufacturing process of the rotor core 22 can be simplified by couple | bonding by the caulking coupling with which the effort of coupling | bonding is easy. However, the coupling | bonding aspect of the electromagnetic steel plate 40 shown here is an example, and if the electromagnetic steel plate 40e located in the edge part is couple | bonded by welding at least, the coupling | bonding aspect of the other electromagnetic steel plate 40 will be especially limited. Not. Therefore, for example, a larger number of electromagnetic steel plates 40 may be joined by welding. Further, as long as the electromagnetic steel plates 40 can be firmly bonded without using the end plate 50, other bonding methods such as adhesive bonding may be used instead of welding.

  Moreover, in this embodiment, in order to prevent peeling of the electromagnetic steel sheet 40 more effectively, a resin mold portion 44 that covers the outer periphery of the rotor core 22 is provided. The resin mold portion 44 is formed by laminating a plurality of electromagnetic steel plates 40 constituting the rotor core 22 and compressing them in the axial direction (in a state where the steel plates are in close contact with each other). Is made up of. When the mold material is solidified, the movement of the electromagnetic steel sheet 40 is restricted, and the electromagnetic steel sheets 40 are maintained in close contact with each other. Thereby, peeling of the electromagnetic steel sheet 40 and the like are effectively prevented.

  Further, the axial end portion of the resin mold portion 44 constitutes a mold end portion 46 that covers an outer peripheral side portion from the permanent magnet 30 in the axial end surface of the rotor core 22. As shown in FIG. 3, the mold end 46 is inclined so as to gradually become thicker (toward the outer side in the axial direction) as it goes toward the outer peripheral side. This is for more efficiently guiding the flowing refrigerant to the coil end 21, which will be described in detail later. The mold material may be made of only a resin, but is preferably made of a magnetic material-containing resin in order to improve the magnetic characteristics of the rotor 12.

  In the present embodiment, as shown in FIGS. 2 and 3, a guide portion 48 that is a substantially linear protrusion is provided on the end surface of the rotor core 22. The guide portion 48 is a member for more reliably guiding the refrigerant discharged from the refrigerant flow path 32 to the end portion of the permanent magnet 30. In this embodiment, this guide part 48 is comprised with the weld bead which is a rise of a welding trace. In the case of a weld bead, the guide part 48 is formed by a weld bead, and there is a degree of freedom in which various shapes can be freely formed, and the tool used for welding the electromagnetic steel sheet 40e at the end described above is used as it is. This is because it can be easily formed. However, as a matter of course, the guide portion 48 may be formed by other means instead of the weld bead as long as the refrigerant flow can be formed. Further, in the present embodiment, the guide portion 48 is a plurality of linear protrusions extending radially, but if the refrigerant can be guided to the permanent magnet 30, the shape, number, arrangement angle, etc. of the guide portion 48 are appropriately determined. It may be changed. In this embodiment, the protrusion formed on the end surface of the rotor core 22 is used as the guide portion 48, but a groove or a recess formed on the end surface of the rotor core 22 may be used as the guide portion 48.

  Next, the flow of the refrigerant in the rotating electrical machine 10 having such a configuration will be described. The refrigerant supplied to the hollow portion 34 of the rotor shaft 24 flows into the refrigerant flow path 32 in the rotor core 22 through the communication path 36. The refrigerant that has reached the refrigerant flow path 32 flows in the axial direction along the refrigerant flow path 32 and is discharged from the end of the refrigerant flow path 32 to the outside. The discharged refrigerant moves on the end face of the rotor core 22 toward the outside in the radial direction by the centrifugal force generated with the rotation of the rotor 12. The guide part 48 guides the refrigerant so that the refrigerant is directed to the permanent magnet 30 more reliably. Here, the end face of the permanent magnet 30 is exposed to the outside as it is without being covered with the end plate 50 on the end face of the rotor core 22 through which the refrigerant flows. Therefore, the refrigerant can directly contact the permanent magnet 30 in the process of moving on the end face of the rotor core 22. When the refrigerant directly contacts the permanent magnet 30, heat exchange is performed between the refrigerant and the permanent magnet 30, and the permanent magnet 30 is efficiently cooled. And as a result, the thermal demagnetization accompanying a temperature rise is suppressed and the efficiency of a rotary electric machine can be improved more.

  The refrigerant carried to the outer side in the radial direction reaches the mold end 46 which is the end of the resin mold 44. As described above, the mold end 46 is inclined so as to become thicker (outward in the axial direction) as it goes outward in the radial direction. Therefore, the refrigerant that has hit the mold end 46 flows along the inclination of the mold end, that is, flows toward the outside in the axial direction as it approaches the outside in the radial direction. In the case of such a flow, the refrigerant easily reaches the coil end 21 without falling into the gap between the rotor 12 and the stator 14. As a result, the coil end 21 that generates a large amount of heat can be cooled more efficiently, and the efficiency of the rotating electrical machine 10 can be further improved.

  That is, according to the present embodiment, not only the coil end 21 but also the permanent magnet 30 can be efficiently cooled, and as a result, the efficiency of the rotating electrical machine 10 can be further improved. In addition, the structure demonstrated here is an example, Among the several electromagnetic steel plates 40 which comprise the rotor core 22, at least the electromagnetic steel plate 40e located in the end part is adjoined by another electromagnetic steel plate by welding or adhesion | attachment. As long as it adheres to 40 and the end plate 50 is omitted, other configurations may be changed as appropriate.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Rotor, 14 Stator, 16 Stator core, 20 Stator coil, 21 Coil end, 22 Rotor core, 23 Magnet hole, 24 Rotor shaft, 30 Permanent magnet, 32 Refrigerant flow path, 34 Hollow part, 36 Communication path, 38 Caulking part, 40 electromagnetic steel plate, 44 resin mold part, 46 mold end part, 48 guide part, 50 end plate, 52 discharge hole.

Claims (6)

A rotating electrical machine comprising: a rotor that rotates around an axis; and a stator that is disposed around an outer periphery of the rotor,
The rotor is
A rotor core formed by laminating a plurality of steel plates in the axial direction, and at least the steel plate located at the end in the axial direction among the plurality of steel plates is fixed to another steel plate adjacent by welding or adhesion; and
With the end face exposed to the outside, a plurality of magnets inserted through a plurality of magnet holes penetrating the rotor core in the axial direction;
A refrigerant flow path provided in an inner peripheral side position from the plurality of magnets and penetrating the rotor core in the axial direction;
A rotating electrical machine comprising: The rotating electrical machine according to claim 1,
A rotating electrical machine, wherein a guide portion that guides the refrigerant discharged from the end portion of the refrigerant flow path to the vicinity of the end portion of the magnet is formed on an end surface of the rotor core. The rotating electrical machine according to claim 2,
The rotating electrical machine wherein the guide portion is formed of a weld bead. The rotating electrical machine according to any one of claims 1 to 3,
The rotary electric machine further includes a resin mold portion that covers at least an outer periphery of the rotor core. The rotating electrical machine according to claim 4,
The resin mold portion includes a mold end portion that covers an outer peripheral side portion of the rotor core in the axial direction end surface of the rotor core,
The rotating electric machine according to claim 1, wherein the mold end portion is inclined so as to go outward in the axial direction as it approaches the radially outer side. The rotating electrical machine according to claim 4 or 5,
The rotating electrical machine, wherein the resin mold part is made of a resin containing a magnetic material.

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