JP2014155242A - Magnet embedded rotor for rotary electric machine and rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve torque generation efficiency while preventing magnets from being demagnetized by a diamagnetic field in a magnet embedded rotor for a rotary electric machine.SOLUTION: In a rotor 14 for a rotary electric machine, magnets 22a, 22b are disposed in magnet accommodation holes 28a, 28b. The magnets 22a, 22b include high coersive regions 23 in which a coercive force is higher than other magnet regions, in both end portions in a rotor axis direction. The magnet accommodation holes 28a, 28b include accommodation parts 30a, 30b for accommodating the magnets 22a, 22b and voids 32a, 32b communicating to the accommodation parts. On wall surfaces 36a, 36b forming the voids 32a, 32b, protrusions 38, 40 protruding inside of the voids 32a, 32b in the vicinity of circumferential end faces of the magnets 22a, 22b are formed at positions of avoiding the high coersive regions 23 of the magnets 22a, 22b inside of the voids 32a, 32b along the rotor axis direction.

Description

  The present invention relates to a magnet-embedded rotor of a rotating electrical machine and a rotating electrical machine using the same.

  Conventionally, for example, Japanese Unexamined Patent Application Publication No. 2011-199944 (hereinafter referred to as Patent Document 1) discloses a permanent magnet embedded rotor of a rotating electrical machine. As shown in FIG. 8, the rotor of this Patent Document 1 has a permanent magnet 86 accommodated in an accommodation hole 84 formed in the rotor core 82. The housing hole 84 includes a housing portion 87 that houses the permanent magnet 86, and a gap 90 that communicates with the outer circumferential side of the housing portion 87. The formation surface of the air gap 90 is a magnetic pole side formation surface 92a that is continuous with the magnetic pole facing surface 88a of the accommodation hole 84 that faces the magnetic pole surface 86a that is the radially outer surface of the permanent magnet 86, and the opposite surface that is the radially inner surface of the permanent magnet 86. It is comprised from the antimagnetic pole side formation surface 92b continuing to the antimagnetic pole opposing surface 88b of the accommodating hole 84 facing the magnetic pole surface 86b. Projections 94 and 96 are formed on the magnetic pole side forming surface 92a and the opposite magnetic pole side forming surface 92b of the air gap 90 so as to face each other.

JP 2011-199944 A

  In the rotor described in Patent Document 1, the magnetic field F of the demagnetizing field that has flowed into the inside from the outer peripheral surface of the rotor core 82 is directed to the magnetic pole surface 86 a of the permanent magnet 86, and the protrusions 94 and 96 of the air gap 90. The magnetic field is distributed to the one induced to the opposite magnetic pole surface 86b side of the permanent magnet 86. Accordingly, there is an effect that the permanent magnet 86 can be prevented from being demagnetized by the action of the demagnetizing field.

  However, the protrusions 94 and 96 provided in the air gap 90 not only serve as a demagnetizing magnetic flux guiding path, but also the magnetic flux generated from the magnetic pole face 86a of the permanent magnet 86 is short-circuited as shown by a broken line in FIG. As a result, it goes around to the opposite pole face 86b. Then, the wraparound or short circuit of the magnetic flux does not contribute to the torque generation of the rotor, and there is a problem that the torque generation efficiency of the rotating electrical machine is reduced.

  An object of the present invention is to improve torque generation efficiency while suppressing demagnetization of a magnet due to a demagnetizing field in a magnet embedded rotor of a rotating electrical machine.

  A magnet-embedded rotor of a rotating electrical machine according to the present invention is a magnet-embedded rotor of a rotating electrical machine comprising a rotor core made of a magnetic material and a magnet disposed in a magnet housing hole formed in the rotor core, The magnet includes a high coercivity region having a coercivity higher than that of other magnet regions at least at both end portions in the rotor axial direction, and the magnet housing hole includes a housing portion for housing the magnet and a gap portion communicating with the housing portion. The wall surface forming the gap portion is formed with a protrusion protruding inside the gap portion in the vicinity of the circumferential end surface of the magnet, and the protrusion portion is located at a position avoiding the high coercivity region of the magnet. In the part, it is formed along the rotor axial direction.

  In the magnet-embedded rotor of the rotating electrical machine according to the present invention, the protrusion may be formed on the outer diameter side wall surface of the gap and project toward the inner diameter side wall of the gap.

  Further, in the magnet-embedded rotor of the rotating electrical machine according to the present invention, another protrusion may be formed on the inner diameter side wall surface of the gap portion so as to face the protrusion protruding from the outer diameter side wall surface. Good.

  Furthermore, in the magnet-embedded rotor of the rotating electrical machine according to the present invention, the protrusion formed on the inner diameter side wall surface of the gap portion has a positioning function of the magnet disposed in the housing portion of the magnet housing hole. Also good.

  A rotating electrical machine according to another aspect of the present invention includes the magnet-embedded rotor having any one of the above-described configurations and a stator facing the rotor with a gap therebetween.

  According to the magnet-embedded rotor of a rotating electrical machine and the rotating electrical machine using the same according to the present invention, torque generation efficiency can be improved while suppressing demagnetization of the magnet due to a demagnetizing field.

1 is a cross-sectional view of a rotating electrical machine according to an embodiment of the present invention. It is an axial sectional view of the rotating electrical machine shown in FIG. (A) is the elements on larger scale which show the electromagnetic steel plate and magnet which comprise the edge part of a rotor core, (b) is the elements on larger scale which show the electromagnetic steel sheet and magnet which comprise other than the edge part of a rotor core. It is a perspective view of a magnet. It is a perspective view which shows a mode that the magnet arrange | positioned in a magnet accommodation hole was seen from the axial direction edge part of the rotor core. (A) is a perspective view corresponding to FIG. 4 which shows another embodiment of a magnet, (b) is a perspective view corresponding to FIG. 4 which shows another embodiment of a magnet. It is the elements on larger scale corresponding to Drawing 3 (b) showing the modification of a magnet accommodation hole. It is the elements on larger scale which show an example of the conventional magnet embedding type rotor.

  DESCRIPTION OF EMBODIMENTS Embodiments according to the present invention (hereinafter referred to as embodiments) will be described in detail below with reference to the accompanying 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. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that these characteristic portions are used in appropriate combinations.

  FIG. 1 is a cross-sectional view along a direction orthogonal to the rotation center axis C of the rotating electrical machine 10 according to the present embodiment. Hereinafter, a direction along the rotation center axis C is referred to as an axial direction, a radial direction with the rotation center axis C as a base point is referred to as a radial direction, and a direction around the rotation center axis C is referred to as a circumferential direction. FIG. 2 is a cross-sectional view along the axial direction of the rotating electrical machine 10 shown in FIG.

  As shown in FIGS. 1 and 2, the rotating electrical machine 10 includes a stator 12 having a substantially cylindrical shape, and a rotor 14 provided on the inner peripheral side of the stator 12. The rotor 14 is rotatably disposed so as to face the stator 12 with a gap therebetween.

  The stator 12 is configured by laminating a large number of magnetic plates made of, for example, electromagnetic steel plates. The stator 12 includes an annular yoke portion 16 and a teeth portion 18 that protrudes radially inward from the yoke portion 16 and is uniformly arranged in the circumferential direction. A coil 19 is wound around the teeth portion 18 of the stator 12 by, for example, distributed winding.

  The rotor 14 is a permanent magnet embedded rotor, and includes a substantially cylindrical rotor core 20 and a magnet 22 embedded in the rotor core 20. The rotor core 20 is also configured by laminating a large number of magnetic plates made of, for example, electromagnetic steel plates.

  A shaft hole 24 is formed through the central portion of the rotor core 20. A shaft (not shown) is penetrated and fixed to the shaft hole 24 by, for example, interference fitting or press fitting. This shaft is rotatably supported by a bearing member provided in a case that houses the rotating electrical machine 10.

  As shown in FIG. 2, the rotor core 20 is partitioned into an end region 20a located on both end sides in the axial direction and an intermediate region 20b other than these end regions 20a. The end region 20a and the intermediate region 20b are different in the shape of the gap portion of the magnet accommodation hole formed in the rotor core 20. Details thereof will be described later.

  The rotor 14 has a plurality of magnetic poles 26. In the present embodiment, eight magnetic poles 26 are provided at equal intervals in the circumferential direction. The magnet 22 embedded in each magnetic pole 26 is constituted by a pair of magnets 22a and 22b.

  The pair of magnets 22 a and 22 b are formed in the same shape and size, have a rectangular end face shape and a transverse cross-sectional shape, and extend in the axial direction with substantially the same length as the rotor core 20. Further, the pair of magnets 22 a and 22 b are arranged so as to spread in a substantially V shape toward the outer peripheral surface 21 side of the rotor core 20 in each magnetic pole 26.

  In this embodiment, an example in which two magnets 22a and 22b are included in one magnetic pole 26 will be described. However, the present invention is not limited to this, and one magnetic pole 26 may include one magnet. Or more than two magnets may be included.

  The pair of magnets 22a and 22b are inserted and disposed in the magnet housing holes 28a and 28b formed in the rotor core 20 in the axial direction. The magnets 22a and 22b are fixed to the rotor core 20 using an adhesive such as a resin in the magnet housing holes 28a and 28b.

  FIG. 3 is a partially enlarged view of the magnetic pole 26 as viewed from the axial direction. FIG. 3A shows an electromagnetic steel plate and magnets 22a and 22b constituting the end region 20a of the rotor core 20, and FIG. An electromagnetic steel sheet and magnets 22a and 22b constituting the region 20b are shown.

  As shown in FIGS. 3A and 3B, the magnet housing holes 28a and 28b formed in the rotor core 20 are provided with respect to the housing portions 30a and 30b for housing the magnets 22a and 22b and the housing portions 30a and 30b. And gaps 32a and 32b communicating with the outer sides of the magnetic pole 26 in the circumferential direction.

  These air gap portions 32a and 32b function as magnetic flux barriers (magnetic flux barriers) because they include air gaps that have a remarkably larger magnetic resistance than electromagnetic steel sheets. Thereby, the magnetic flux which came out of the magnetic pole surface which is the surface of the magnet 22a, 22b on the radial outer side passes through the inside of the electrical steel sheet constituting the rotor core 20 on the counter magnetic pole surface which is the surface of the magnet 22a, 22b on the radial inner side. Prevents or suppresses short circuiting and shorting.

  The accommodating portions 30a and 30b of the magnet accommodating holes 28a and 28b are formed in a rectangular shape substantially corresponding to the magnets 22a and 22b. A gap 34 that fills the magnet housing holes 28a and 28b with resin or the like for fixing the magnets 22a and 22b between the wall surfaces of the housing portions 30a and 30b and the magnets 22a and 22b at the circumferential center position of the magnetic pole 26. Is formed.

  The wall surfaces forming the gap portions 32a and 32b of the magnet housing holes 28a and 28b are located on the radially outer side, but are opposed to the outer diameter side wall surface 36a and located on the radially inner side with the outer diameter side wall surface 36a sandwiched between the gaps. And an inner diameter side wall surface 36b.

  As shown in FIG. 3B, in the intermediate region 20b (see FIG. 2) of the rotor core 20, a first protrusion 38 is formed on the outer diameter side wall surface 36a of the gaps 32a and 32b. The first protrusion 38 is located near the end face on the outer side in the circumferential direction of the magnets 22a and 22b, and protrudes toward the inner diameter side wall surface 36b of the gaps 32a and 32b.

  On the other hand, the 2nd protrusion 40 is formed in the internal-diameter side wall surface 36b of space | gap part 32a, 32b. The second protrusion 40 is located in the vicinity of the outer circumferential surface of the magnets 22a and 22b, protrudes toward the outer diameter side wall surface 36a of the gaps 32a and 32b, and faces the first protrusion 38. Yes. Here, the base part of the 2nd protrusion part 40 functions also as a positioning part which positions magnet 22a, 22b accommodated in accommodating part 30a, 30b.

  As described above, in the magnet housing holes 28a and 28b in the intermediate region 20b of the rotor core 20, the first and second protrusions 38 and 40 provided in the gaps 32a and 32b approach each other and the magnetic resistance becomes relatively small. Therefore, a part of the magnetic field F (see FIG. 8) of the demagnetizing field that has entered the rotor core 20 from the outer peripheral surface 21 is guided and distributed to the opposite magnetic pole surface side of the magnets 22a and 22b.

  On the other hand, in the end region 20a (see FIG. 1) of the rotor core 20, as shown in FIG. 3A, the first and second gaps 32a and 32b of the magnet housing holes 28a and 28b are formed as described above. The protrusions 38 and 40 are not provided. Specifically, the outer diameter side wall surfaces 36a of the gap portions 32a and 32b have a shape that is connected substantially straight to the outer diameter side wall surfaces of the accommodation portions 30a and 30b of the magnet accommodation holes 28a and 28b. Further, the inner diameter side wall surfaces 36b of the gap portions 32a and 32b are formed so as to protrude toward the outer diameter side wall surface 36a only by forming the step portions 36c for positioning the magnets 22a and 22b in the accommodating portion 30b. is not.

  As described above, the magnet housing holes 28a and 28b in the end region 20a of the rotor core 20 function effectively as a flux barrier because the protrusions are not provided on the wall surfaces of the gaps 32a and 32b, and the magnets 22a and 22b are surrounded by the periphery. The wraparound of the magnetic flux at the outer end portion in the direction can be suppressed and the magnetic flux can be directed to the outside of the rotor core 20, and as a result, the torque generation efficiency can be improved.

  In this case, since there is no function to disperse the magnetic flux F of the demagnetizing field in the gaps 32a and 32b, there is a concern about demagnetization due to the demagnetizing field at the axial ends of the magnets 22a and 22b. Therefore, in the present embodiment, magnets 22a and 22b having high coercivity regions having higher coercive force than other magnet regions at both end portions in the axial direction are used.

  FIG. 4 is a perspective view showing the magnets 22a and 22b in the present embodiment. FIG. 5 is a perspective view showing a state in which the magnet 22b disposed in the magnet accommodation hole 28b is viewed from one end of the rotor core 20 in the axial direction.

  As shown in FIG. 4, the magnets 22 a and 22 b include high coercivity regions 23 that are portions having a high coercivity at both ends in the axial direction. Such a high coercive region 23 can be formed by diffusing rare earth elements such as dysprosium (Dy) and terbium (Tb) on the end surface of the base material of the magnets 22a and 22b. Specifically, for example, dysprosium or the like is attached only to the end regions of the magnets 22a and 22b by a sputtering method, vapor deposition method, coating method or the like, and then the magnets 22a and 22b are heated so It is formed by diffusing or penetrating into the field.

  As shown in FIG. 5, when the magnet 22b is disposed in the magnet housing hole 28b, the first and second protrusions 38 and 40 of the gap portion 32b are spaced away from the highly coercive region 23 of the magnet 22b. It is formed in the axial direction in the portion 32b. More specifically, the axial end surfaces of the first and second projecting portions 38 and 40 are located behind the axial end surface of the rotor core 20, and the projecting end surfaces are the high coercivity region 23 and other magnet regions in the magnet 22b. It almost coincides with the boundary. The same applies to the magnet 22a not shown in FIG.

  As described above, in the rotor 14 according to the present embodiment, the magnets 22a and 22b having the high coercive regions 23 at both ends in the axial direction are used, and the magnets 22a and 22b other than the high coercive regions that are relatively low coercive force portions. Corresponding to this portion, first and second projecting portions 38, 40 that perform a function of dispersing the demagnetizing magnetic flux are provided in the gap portions 32a, 32b of the magnet housing holes 28a, 28b. As a result, demagnetization due to the demagnetizing field can be effectively suppressed for the entire axial direction of the magnets 22a and 22b, and the torque generation efficiency can be improved by preventing or reducing the wraparound of the magnetic flux at the axial ends of the magnets 22a and 22b. Can be improved.

  Note that the rotor according to the present invention is not limited to the above-described configuration, and various changes and improvements can be made within the scope of matters described in the claims of the present application and a range equivalent thereto.

  For example, in the above description, the magnets 22a and 22b embedded in the rotor 14 have been described as having the high coercivity regions 23 at both ends in the axial direction. However, the present invention is not limited to this. What is necessary is just to provide the area | region where a coercive force is higher than another magnet area | region in the part.

  For example, as shown in FIG. 6A, the magnets 22a and 22b have high coercivity regions 23 at both end portions in the axial direction, and are known to be portions where demagnetization due to a demagnetizing field is likely to occur. A high coercive region may also be formed around the ridge line corner 25 along the axial direction by diffusion of dysprosium or the like.

  In addition, as shown in FIG. 6B, dysprosium or the like may be attached and diffused over the entire surface of the magnets 22a and 22b. Even in this case, as shown by the fingerprint-like isoconcentration lines in FIG. 6B, the diffusion concentration of dysprosium and the like decreases from the surface of the magnets 22a and 22b toward the inside, so that both end portions in the axial direction are magnet internal regions. It can be said that the coercive force is higher than that.

  Further, in the above description, it has been described that the first protrusion 38 is provided on the outer diameter side wall surface 36a of the gaps 32a, 32b of the magnet housing holes 28a, 28b and the second protrusion 40 is provided on the inner diameter side wall surface 36b. However, the present invention is not limited to this. For example, as shown in FIG. 7, in the intermediate region 20b of the rotor core 20, the first protrusions 38 may be provided only on the outer diameter side wall surfaces 36a of the magnet housing holes 28a, 28b. The second protrusion 40 may be provided only on the side wall surface 36b.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Stator, 14 Rotor, 16 Yoke part, 18 Teeth part, 19 Coil, 20 Rotor core, 20a End area, 20b Intermediate area, 21 Outer peripheral surface, 22, 22a, 22b Magnet, 23 High coercive area, 24 Shaft hole, 25 ridge line corner, 26 magnetic pole, 28a, 28b magnet accommodation hole, 30a, 30b accommodation portion, 32a, 32b gap portion, 34 gap, 36a outer diameter side wall surface, 36b inner diameter side wall surface, 36c stepped portion, 38th 1 protrusion (protrusion), 40 second protrusion (protrusion). C rotation center axis, F magnetic flux.

Claims (5)

A rotor-embedded magnet rotor of a rotating electrical machine comprising a rotor core made of a magnetic material, and a magnet disposed in a magnet housing hole formed in the rotor core,
The magnet is provided with a high coercivity region having a higher coercivity than other magnet regions at least at both end portions in the rotor axial direction,
The magnet housing hole includes a housing portion for housing the magnet and a gap portion communicating with the housing portion,
The wall surface forming the gap is formed with a protrusion protruding inward of the gap in the vicinity of the circumferential end surface of the magnet, and the protrusion is located inside the gap at a position avoiding the high coercivity region of the magnet. A rotor embedded in a magnet, which is formed along the rotor axial direction. In the rotary electric machine embedded magnet rotor according to claim 1,
The projecting portion is formed on an outer diameter side wall surface of the gap portion and protrudes toward an inner diameter side wall surface of the gap portion. In the rotor embedded in a rotating electric machine according to claim 2,
A magnet-embedded rotor for a rotating electrical machine, wherein another protrusion is formed on the inner diameter side wall surface of the gap so as to face the protrusion protruding from the outer diameter side wall surface. In the rotor embedded in a rotating electric machine according to claim 3,
The protrusion formed on the inner diameter side wall surface of the gap portion positions the magnet arranged in the accommodating portion of the magnet accommodating hole, and is a magnet-embedded rotor of a rotating electrical machine. A magnet-embedded rotor according to any one of claims 1 to 5,
A rotating electrical machine comprising: a stator facing the rotor with a gap therebetween.

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