WO2016125853A1

WO2016125853A1 - Inclusive magnet-type synchronous machine and rotor for same

Info

Publication number: WO2016125853A1
Application number: PCT/JP2016/053337
Authority: WO
Inventors: 萱野　雅浩; 橋本　擁二
Original assignee: 愛知製鋼株式会社
Priority date: 2015-02-04
Filing date: 2016-02-04
Publication date: 2016-08-11
Also published as: JP2016144369A; JP5975123B2

Abstract

Provided is a rotor for an inclusive magnet-type synchronous machine with which it is possible to maintain or increase output while effectively utilizing a rare earth magnet serving as a bond magnet. This rotor (R) for an inclusive magnet-type synchronous machine is provided with: a body (1) comprising a substantially columnar or substantially cylindrical soft magnetic material, the body (1) having a plurality of inclusion parts (13), which are closed-ring cylindrical voids curving in a concave shape towards the outer circumference side and extending in the rotary center axis direction, disposed around a rotary center axis (O); and permanent magnets (2) comprising a rare earth bond magnet, formed upon being packed into the inclusion parts. The inclusion parts according to the present invention are characterized in having rectangular parts (131, 132), comprising flat inner wall surfaces extending in the rotary center axis direction and facing each other in parallel, in a section from an outer circumference end nearest to the outer peripheral edge of the body to an inner peripheral end nearest to the rotary center axis of the body. The magnetic flux distribution of the bond magnets, which are formed packed into the rectangular parts, becomes substantially uniform. The bond magnets exhibit a higher magnetic flux density and a reduced demagnetization amount.

Description

Internal magnet type synchronous machine and its rotor

The present invention relates to an internal magnet type synchronous machine including a rare earth bonded magnet and a rotor thereof.

There are various types of permanent magnet motors (simply called “motors” including generators). Recently, with the development of inverter control and the widespread use of rare earth magnets with high magnetic properties, attention has been focused on synchronous machines that can save power, have high efficiency, and expect high torque or high output.

The synchronous machine is a motor having a permanent magnet for a field in a rotor (rotor) and an armature winding (coil) in a stator (stator), and a multiphase alternating current ( AC) is a motor that rotates by generating a rotating magnetic field in the stator. Synchronous machines are roughly classified into a surface magnet type motor (SPM) in which permanent magnets are arranged on the rotor surface and an embedded (internal) magnet type motor (IPM) in which permanent magnets are embedded in the rotor. However, IPM, which has high reliability by utilizing reluctance torque and can prevent scattering of magnets, is now becoming the mainstream.

In the conventional IPM, a sintered magnet that has been cut or polished into a predetermined shape has been used as a permanent magnet constituting the magnetic pole of the rotor. However, such a sintered magnet has a low degree of freedom in shape, and is easily damaged when inserted into a slot, and a bonding process or the like is required for fixing the sintered magnet. For this reason, in recent IPMs, bond magnets directly filled in slots have been used as permanent magnets constituting the magnetic poles of the rotor. The description regarding the rotor using such a bonded magnet exists in the following patent document, for example.

JP 2014-82928 A

Patent Document 1 discloses a bonded magnet that can increase the ratio (φa / Ld) of the flux linkage (φa) to the d-axis inductance (Ld) in order to improve the rotor rotation controllability (particularly the flux weakening controllability). The shape (that is, the slot shape of the rotor core) is proposed. Specifically, the bonded magnet included in the rotor has a shape having a main body portion that bends convexly toward the outer edge side of the rotor core and an end portion that extends from both circumferential ends of the main body portion toward the outer peripheral edge of the rotor core. Propose to do.

However, in the case of a high-performance motor to which a large reverse magnetic field is applied from the stator side, such a bonded magnet tends to demagnetize a region near the outer periphery of the rotor. This makes it impossible to effectively use the entire bonded magnet containing rare earth elements, and it is not possible to sufficiently secure an output corresponding to the amount of rare earth magnet used.

The present invention has been made in view of such circumstances, and provides an internal magnet type synchronous machine capable of maintaining or improving output while effectively utilizing a rare earth magnet as a bonded magnet, and a rotor thereof. For the purpose.

As a result of extensive research and trial and error, the present inventor has improved the magnetic flux density distribution generated from the bonded magnet filled in the slot by devising the slot shape of the rotor core. I came up with the idea of suppressing demagnetization of magnets (more precisely, the rare earth magnets that make up them). By specifically developing this idea, the present invention described below has been completed.

《Rotator of internal magnet type synchronous machine》
(1) The rotor (simply referred to as “rotor”) of the internal magnet type synchronous machine of the present invention is made of a substantially columnar or substantially cylindrical soft magnetic material, curved in a concave shape toward the outer peripheral side, and has a center of rotation. A main body in which a plurality of inclusions, which are closed ring-shaped cylindrical gaps extending in the axial direction, are arranged around the rotation center axis, and a permanent magnet made of a rare-earth bonded magnet formed by filling the inclusions, A rotor of an internal magnet type synchronous machine, wherein the inner packet part is in a section from an outer peripheral end closest to the outer peripheral edge of the main body to an inner peripheral end closest to the rotation central axis of the main body. It has the rectangular part which consists of a planar inner wall surface extended in the axial direction and opposed in parallel.

(2) According to the rotor of the present invention, it is possible to suppress the demagnetization of the rare earth magnets constituting the bonded magnet, and without increasing the amount of rare earth magnets used, IPM "," synchronous machine "or" motor "), and the performance of the motor can be maintained while reducing the amount of rare earth magnets used.

The reason why the rotor of the present invention can suppress the demagnetization of the rare earth magnet in the bonded magnet is considered as follows. The inner packet portion (also referred to as “slot”) according to the present invention is a closed cylindrical (groove-shaped) gap that is curved concavely toward the outer peripheral side of the rotor body (also referred to as “rotor core”). Consists of. For this reason, even if a strong reverse magnetic field is applied from the outside (stator side) of the rotor, the reverse magnetic field is dispersed by the soft magnetic material existing in the curved interior, and the bonded magnet filled and molded in the inner packet part. Acts on rare earth magnets. For this reason, the rare earth magnet in the bonded magnet according to the present invention is less likely to be demagnetized than when the slot is formed in a convex shape on the outer peripheral side of the rotor core.

Next, the inner packet part according to the present invention has a rectangular part defined by parallel opposing planar inner wall surfaces that maintain a constant interval (inner width). The lines of magnetic force that pass through the slots (voids) in the region of the rectangular part are normal to the inner wall surface (the outer peripheral surface and the inner peripheral surface of the slot (void)), and at least within the rectangular part, the slots (voids) The magnetic flux density distribution of the magnetic flux lines passing through) becomes substantially uniform. When such a slot is filled (injected or the like) with a mixture of magnet powder and molten resin, a bonded magnet that is uniformly oriented and magnetized along the orientation magnetizing magnetic field described above can be obtained. As a result, the lines of magnetic force that pass through the bonded magnet in the region of the rectangular portion are normal to the inner wall surface (the outer peripheral surface and the inner peripheral surface of the bonded magnet), and pass through the bonded magnet at least within the rectangular portion. The magnetic flux density distribution of the magnetic flux lines is substantially uniform (see FIG. 1A).

Conversely, when using a bonded magnet having a degree of freedom during molding for IPM that utilizes reluctance torque, a curved surface with a constant inner width (especially a curved surface having a circular cross section) in a conventional slot (inner package). ), The magnetic lines of force that pass through the slot (gap) radiate from the inner inner wall surface of the slot (the outer peripheral side of the main body) to the outer inner wall surface (the inner peripheral side of the main body). The magnetic flux density was diluted on the wall surface side, the magnetic flux density was decreased on the outer inner wall surface side of the slot, and the magnetic flux density generated in the slot (gap) was generally reduced.

As a result, the magnetic lines of force that pass through the bonded magnet filled in the conventional inner envelope portion spread radially from the inner inner wall surface (the outer peripheral side of the main body) of the bond magnet to the outer inner wall surface (the inner peripheral side of the main body). The magnetic flux density was diluted on the side, the magnetic flux density (distribution) was reduced on the outer inner wall surface side of the slot, and the magnetic flux density generated in the bond magnet was relatively small (see FIG. 1B). The distribution diagrams of magnetic flux density shown in FIG. 1A and FIG. 1B show the same manufacturing conditions such as the raw materials (magnet powder, resin, etc.) constituting the bonded magnet, the blending ratio, the supplied magnetic field, etc. The area (magnet cross-sectional area) is also set to be the same.

As can be seen from the magnetic flux density distribution (FIG. 1A) of the rotor alone that does not consider the presence of the stator, in the rectangular type rotor of the present invention, for example, the residual magnetic flux density Bd2a at the position Xa shown in FIG. Compared to the residual magnetic flux density Bd1b at the equivalent position Xb in FIG. 1B), the difference in the orientation magnetization magnetic field described above has a high magnetic flux density, and the bond magnet as a whole exhibits a high residual magnetic flux density distribution.

Here, when the synchronous machine incorporating the rotor including the bond magnet is operated, the rare earth magnet in the bond magnet is a recoil wire passing through the operating point (P ₁ , P ₂ ) on the BH demagnetization curve. Will operate on (l ₁ , l ₂ ) (see FIG. 3). P ₂ represents the operating point of the rectangular type rotor of the present invention (FIG. 1A), P ₁ indicates the operation of the conventional arc-type rotor (Fig. 1B). Naturally, the operating points (P ₁ , P ₂ ) on the BH demagnetization curve slide to a relatively higher position than the operating point of the rotor alone.

The difference between the residual magnetic flux density (Br ₀ ) initially possessed by the rare earth magnet and the residual magnetic flux density (Br ₁ , Br ₂ ) obtained from the extension of the recoil wire is referred to as a decrease amount of the magnetic flux density (simply referred to as “demagnetization amount”). .) For this reason, as the magnetic flux density generated in the bond magnet (rare earth magnet) with the same amount of bond magnet used increases, the operating point on the BH demagnetization curve shifts to the higher magnetic flux density side (P ₁ → P ₂ ). Further, the amount of demagnetization is also reduced (ΔB ₁ > ΔB ₂ ).

Normally, the permeance coefficient of a magnet is determined by the shape of the magnet. However, in the case of an IPM in which a rotor filled with a bonded magnet without gaps in the slot is placed close to the stator, the operating point is very high, and the interlinkage magnetic flux is almost equal to the magnet volume It depends on. In the case of such an IPM, the substantial permeance coefficient includes not only the outer shape of the entire magnet, but also the overall shape including the manner in which the rare earth anisotropic magnet particles distributed in the bonded magnet are oriented and magnetized. It can be said that it is determined by the magnet performance as a result.

Under such circumstances, according to the present invention, even when anisotropic rare earth magnet powder having fine crystals that are relatively difficult to be oriented is used as a magnet raw material to be filled and molded into the slots of the rotor, Although the area is large, the magnetic flux density region higher than the conventional one can be expanded, the effective permeance coefficient can be further increased, the output of the IPM can be improved, and the demagnetization resistance can be improved.

Further, in the conventional slot on the reverse arc, the magnetic field lines passing through the slot (gap) are radially radiated from the inner inner wall surface (outer side of the main body) of the slot (gap) to the outer inner wall surface (inner side of the main body). It was in a state of spreading over the entire range. On the other hand, in the slot of the present invention, it is an inner packet part that is a ring-shaped cylindrical space that is concavely curved toward the outer peripheral side and extends in the direction of the central axis of rotation, and the inner packet part is an outer peripheral edge of the main body. In the section from the outer peripheral end closest to the inner peripheral end closest to the rotation center axis of the main body, there is a rectangular portion consisting of a planar inner wall surface extending in the direction of the rotation center axis and facing in parallel. It can be made to concentrate on the part which has spread radially from the inner inner wall surface to the outer inner wall surface. Thereby, in the rotor of the present invention, it is possible to improve the magnetic characteristics and the anti-demagnetization characteristics of the magnet while utilizing the reluctance torque as a whole. In the present invention, magnetization may be performed separately.

Thus, in the rotor of the present invention, the bonded magnet filled in at least the rectangular portion exhibits a uniform and large magnetic flux density, and the amount of demagnetization of the rare earth magnet in the bonded magnet is suppressed. It is possible to maintain the performance of the synchronous machine or improve the performance while suppressing the amount.

For convenience, the magnetic flux density distribution exerted by the bonded magnet in the inner packet part (particularly, the rectangular part) has been described. However, the above description can be applied similarly to the magnetic field acting on the inner packet part from the outside. For example, the distribution of the applied magnetic field acting on the bonded magnet and the distribution of the orientation magnetic field applied to the inner portion during filling molding of the bonded magnet made of a rare earth anisotropic magnet can be said to be the same as the distribution of the magnetic flux density described above. .

<Internal magnet type synchronous machine>
(1) The present invention can be grasped not only as the rotor described above but also as an internal magnet type synchronous machine using the rotor. That is, the present invention includes the above-described rotor, and a stator having a coil (equally) disposed on the outer periphery of the rotor and a yoke that forms a magnetic circuit on the outer peripheral side of the coil. An internal magnet type synchronous machine characterized by the above may be used. As appropriate, the yoke includes a tooth in the coil.

(2) The synchronous machine basically rotates based on an attractive force and a repulsive force generated by a magnetic pole formed by a permanent magnet provided on the rotor and a rotating magnetic field formed by the stator on the outer periphery of the rotor. Force (magnet torque) is generated. However, unlike a surface magnet type synchronous machine, in the case of an embedded magnet type (internal magnet type) synchronous machine, between the (d axis) inductance (Ld) generated in the magnetic pole and the (q axis) inductance (Lq) generated between the magnetic poles. Therefore, the reluctance torque based on the attractive force is often generated in the rotor. In particular, when Ld <Lq, the reluctance torque and the magnet torque are in the same direction, and the output torque can be increased.

Therefore, the rotor according to the present invention also adjusts the shape and arrangement of the permanent magnet (inner part) in the rotor, for example, between the adjacent magnetic poles formed by the permanent magnet and the magnet torque generated by this magnetic pole. It is preferable to have salient poles that generate reluctance torque acting in the same direction.

<< Method for manufacturing rotor of internal magnet type synchronous machine >>
Further, the present invention can be grasped not only as the above-described inner magnet type synchronous machine and its rotor, but also as a method of manufacturing the rotor. That is, the present invention provides a rare earth anisotropic material which becomes a permanent magnet by injection-filling a molten mixture in which a rare earth anisotropic magnet powder is dispersed in a binder resin melted in an inclusion portion having the above-described rectangular portion in an orientation magnetic field. It can also be grasped as a method for manufacturing a rotor of an encapsulated magnet type synchronous machine, comprising an injection molding process for forming a magnetic bond magnet.

<Others>
(1) The internal magnet type synchronous machine of the present invention includes not only an electric motor but also a generator, and the electric motor (motor) in this specification includes a generator (generator) unless otherwise specified. The internal magnet type synchronous machine of the present invention includes a Hall element in addition to the original synchronous machine in which the rotation speed changes in synchronization with the frequency of the alternating current supplied to the coil (armature winding) provided in the stator. Also included is a brushless direct current (DC) motor that generates a rotating magnetic field on the stator side based on the position of the rotor detected by a detecting means such as a rotary encoder or resolver. Incidentally, since the brushless DC motor can change the rotation speed by changing the DC voltage supplied to the inverter, it has excellent controllability like a normal DC motor.

(2) In this specification, the side close to the rotation center of the main body is referred to as “inner side” while the object or target part is viewed relatively, and conversely, the side far from the center of rotation is referred to as “outer side”. . Further, the cylindrical side surface or the column side surface of the main body is referred to as an “outer peripheral side surface”, and an outermost circle (arc) thereof is referred to as an “outer peripheral edge”. Furthermore, the part closest to the rotation center of the target part (including the inner packet part) is referred to as “inner peripheral end”, and the part farthest from the rotation center (part closest to the outer peripheral edge) is referred to as “outer peripheral end”. The “inner peripheral end side” refers to a further inner peripheral side of the inner peripheral end, and the “outer peripheral end side” refers to a further outer peripheral side of the outer peripheral end. In addition, the shape of the “end” in this specification may be linear or planar, and “end” means the vicinity of the “end”.

(3) Unless otherwise specified, “x to y” in this specification includes the lower limit value x and the upper limit value y. A range such as “ab” can be newly set as a new lower limit value or upper limit value for any numerical value included in various numerical values or numerical ranges described in this specification.

It is a distribution map of the magnetic flux density of the bond magnet filled and molded in the inner packet part with a rectangular part. It is a distribution map of the magnetic flux density of the bond magnet filled and molded in the inner packet part having no rectangular part. It is a fragmentary sectional view of the rotor and stator which concern on the Example of this invention. It is a figure which shows a BH demagnetization curve and a recoil line.

The contents described in this specification can be appropriately applied not only to the rotor of the present invention but also to a synchronous machine using the rotor. Matters related to the manufacturing method can also be components related to products if understood as product-by-process. And one or two or more arbitrarily selected from the matters described in the present specification can be added to the above-described components of the present invention. Which embodiment is the best depends on the target, required performance, and the like.

《Rotator of internal magnet type synchronous machine》
(1) Inner part The inner part of the rotor is provided in the main body and includes a gap for disposing a permanent magnet. There are at least two inner inclusions for containing the permanent magnets serving as magnetic poles, and these are usually arranged evenly around the rotation center axis of the main body.

The specific shape of the inner packet part is appropriately adjusted according to the specifications of the synchronous machine, but at least the inner packet part according to the present invention is concavely curved toward the outer peripheral side of the main body and extends in the direction of the rotation center axis. It has a closed cylindrical shape and further has the rectangular portion described above.

The curved shape of the enclosing part includes an outline, a U-shape, a V-shape, a W-shape, a J-shape, etc., and these may be a multilayer-type inclusion portion provided in a radial direction per magnetic pole. The inner packet part preferably has a uniform groove width (distance between the inner wall surface on the inner peripheral side and the outer peripheral side) in order to avoid local concentration of magnetic flux density and orientation magnetic field.

Whatever the shape of the inner packet part is, the bonded magnet filled and molded there basically has a shape along the inner packet part, but the shape of the inner packet part and the shape of the bond magnet do not completely match. May be. For example, if injection molding or the like is performed with a spacer (pin) interposed in the inner packet part, the shape of the inner packet part and the shape of the bond magnet can be intentionally different.

Although it is preferable that as many regions (sections) as possible are composed of rectangular parts, the inner part is curved in a concave shape and cannot be composed of only rectangular parts. Therefore, it is preferable that each inner packet portion has a plurality of rectangular portions and that the adjacent rectangular portions are connected by a smoothly curved connecting portion. At this time, in order to avoid local concentration of the magnetic flux density, it is preferable that the inner width of the connection portion and the inner packet portion is the same. For example, the inner wall surface on the inner circumference side of the connecting portion that connects the inner wall surfaces on the inner circumference side of the adjacent rectangular portions is preferably a curved surface having a circular arc in cross section (perpendicular to the rotation center axis). In addition, it is preferable that the shape of each inner packet portion is symmetric with respect to the magnetic pole center line (plane) because the output characteristics of the synchronous machine are smooth.

(2) Main body The main body of the rotor is made of a soft magnetic material, and is usually made of a laminated body of electromagnetic steel sheets with insulating coating on both surfaces, a dust core or the like obtained by press-molding insulating coated metal particles. The soft magnetic material is preferably an iron-based material such as pure iron, silicon steel, or alloy steel.

The outer peripheral edge of the inner packet part may be in the vicinity of the outer peripheral edge of the main body, but the outer peripheral edge part of the bonded magnet (rare earth magnet) filled in the inner packet part is reduced (irreversibly) by the reverse magnetic field from the stator. It is easy to be magnetized. Therefore, it is preferable that the main body has an open groove portion that opens to the outer peripheral side of the inner packet portion and extends in the direction of the rotation center axis. As a result, the rare earth magnet can be effectively arranged only in the region contributing to the output of the synchronous machine, and it is possible to avoid using a useless rare earth magnet in the region to be demagnetized.

Further, it is preferable that the main body has a protrusion extending to the outer peripheral edge between the open groove parts provided on the outer peripheral edge side of the adjacent inner packet part. In the case where the groove portion is provided on the outer peripheral edge side of the adjacent inner packet portion, it is also conceivable that one groove portion opened on the outer peripheral edge side is also used. However, if an open groove part corresponding to the inner width of the inner packet part is provided on the outer peripheral edge side of the adjacent inner packet part, and a protrusion extending to the outer peripheral edge is provided between them, the protrusion becomes a reluctance as a salient pole. The torque can be improved, and as a result, the performance of the synchronous machine can be improved while suppressing the amount of rare earth magnet used.

《Rare earth bonded magnet》
(1) Raw material A rare earth bonded magnet basically comprises a rare earth magnet powder and a binder resin. The rare earth magnet powder may be a rare earth isotropic magnet powder, but if it is a rare earth anisotropic magnet powder, a high-performance synchronous machine can be obtained while suppressing the amount of rare earth magnet used.

The rare earth magnet powder is, for example, Nd—Fe—B magnet powder, Sm—Fe—N magnet powder, Sm—Co magnet powder or the like. These rare earth magnet powders may be composed of a plurality of types as well as one type. Incidentally, the plurality of types of magnet powders are not limited to those having different component compositions but may have different particle size distributions. For example, Nd—Fe—B magnet powder coarse powder and fine powder may be combined, or Nd—Fe—B magnet powder coarse powder and Sm—Fe—N magnet powder fine powder may be combined. By using such rare earth magnet powder, the filling rate of the magnet powder in the bonded magnet can be improved, and a bonded magnet exhibiting a high magnetic flux density can be obtained. The bonded magnet according to the present invention may be a mixture of rare earth anisotropic magnet powder and / or rare earth isotropic magnet powder and ferrite magnet powder.

As the binder resin, known materials including rubber can be used. For example, polyethylene, polypropylene, polystyrene, acrylonitrile / styrene resin, acrylonitrile / butadiene / styrene resin, methacrylic resin, vinyl chloride, polyamide, polyacetal, polyethylene terephthalate, ultrahigh molecular weight polyethylene, polybutylene terephthalate, methylpentene, polycarbonate, polyphenylene sulfide, It is preferable to use a thermoplastic resin such as polyetheretherketone, liquid crystal polymer, polytetrafluoroethylene, polyetherimide, polyarylate, polysulfone, polyethersulfone, and polyamideimide. Also, thermosetting resins such as epoxy resin, unsaturated polyester resin, amino resin, phenol resin, polyamide resin, polyimide resin, polyamideimide resin, urea resin, melamine resin, urea resin, direal phthalate resin, polyurethane, etc. should be used as appropriate. Can do.

(2) Filling Molding Methods for filling and molding the bonded magnet in the inner packet part according to the present invention include injection molding, compression molding, transfer molding and the like. However, injection molding in which a molten mixture obtained by heating and melting the pellets made of the above-described raw materials is injected and filled into the inner packaging portion and then cooled and solidified is excellent in mass productivity. When the rare earth anisotropic magnet powder is used as the magnet raw material, it is preferable to fill the above-mentioned molten mixture into the inclusion portion to which the orientation magnetic field is applied, because the characteristics of the rare earth magnet can be effectively utilized. In addition, it is good for the heating temperature (temperature of a molten mixture) at the time of injection molding to be less than the Curie point of rare earth magnet powder. It is preferable to use a permanent magnet as the orientation magnetic field source because the manufacturing apparatus can be downsized.

《Use of internal magnet type synchronous machine》
The internal magnet type synchronous machine of the present invention may be used for any purpose. For example, a motor for a vehicle driving motor used in an electric vehicle, a hybrid vehicle, a railway vehicle or the like, a motor for home appliances used in an air conditioner, a refrigerator, a washing machine, or the like. It is suitable for such as.

The present invention will be described more specifically with reference to examples.
<< Internal magnet type synchronous machine: First embodiment >>
The fragmentary sectional view (1/3 of the section perpendicular to rotation center axis O) of stator S and rotor R which are the principal parts which constitute synchronous motor SM which is one example concerning an internal magnet type synchronous machine of the present invention is shown. It was shown in 2. The synchronous motor SM shown in FIG. 2 is a 6 pole 9 slot type. This synchronous motor SM is used as a motor for driving a car, a motor for home appliances, or the like. Hereinafter, the stator S and the rotor R will be described in detail. In FIG. 2, the direction perpendicular to the paper surface is defined as the extending direction of the rotation center axis O (simply referred to as “axial direction”).

(1) Stator The stator S is formed by laminating electromagnetic steel plates (soft magnetic materials) punched into a shape as shown in FIG. 2, and an annular yoke Sa and teeth protruding uniformly from the yoke Sa toward the center. Sb and a slot Sc formed between adjacent teeth Sb. Each slot Sc houses electromagnetic coils C distributed around the teeth Sb. Each electromagnetic coil C is supplied with inverter-controlled three-phase alternating current. As a result, a rotating magnetic field having a synchronous speed corresponding to the frequency and the number of poles is generated in the stator S.

(2) Rotor The rotor R is a rare earth that is filled in a rotor core 1 (main body) formed by laminating electromagnetic steel sheets punched into a shape as shown in FIG. 2 and a slot 13 (inner part) formed in the rotor core 1. An anisotropic bonded magnet 2 (simply referred to as “bonded magnet 2”). In the present embodiment, the bonded magnet 2 is filled in the slot 13 without a gap.

The rotor core 1 has a center hole 11 fitted into a rotating shaft (not shown), an air passage 12 that is uniformly arranged on the outer peripheral side thereof and penetrates in the axial direction, and six that are equally arranged on the outer peripheral side of the air passage 12. An elongated closed ring-shaped cylindrical slot 13 having a shape curved convexly toward the inner peripheral side (a shape curved concavely toward the outer peripheral side), and the rotor core 1 having the same inner width as the slot 13 and extending from the slot 13 Between the notch 14 (open groove portion) that opens in a rectangular shape (a U-shape) toward the outer peripheral edge of the rotor and extends in the axial direction, and extends to the outer peripheral edge of the rotor core 1. And the existing protrusion 15. A bridge 16 bridges adjacent magnetic poles between the outer peripheral end of the slot 13 and the inner peripheral end of the notch 14.

Each slot 13 is composed of continuous through-grooves that are line-symmetric with respect to the center of the d-axis magnetic pole. For convenience, the four sections including the

rectangular portions

131a, 132a, 131b, and 132b are connected to each other and adjacent to each other. It can be divided into three sections consisting of

sections

133a, 133b, and 133c.

The

rectangular portions

131a and 131b are arranged symmetrically with respect to the d axis on the outer peripheral side of the rotor core 1. The

rectangular portions

132 a and 132 b are disposed symmetrically with respect to the d axis on the inner peripheral side of the rotor core 1. All are comprised by the parallel inner wall face extended in an axial direction, and the space | interval (inner width) of these inner wall faces is the same. In the present embodiment, as many rectangular portions as possible are formed in the slot 13 by connecting the end portions of the inner wall surface on the outer peripheral side of each rectangular portion.

The connecting

portions

133a, 133b, and 133c are fan-shaped in their entire cross section, and the inner wall surface on the inner peripheral side of the cross section having an arc shape is the inner wall surface on the inner peripheral side of the adjacent rectangular portion. Connected smoothly. The connecting

portions

133a and 133b are disposed symmetrically with respect to the d axis.

Since the cutout portion 14 is provided on the outer peripheral end side of the

rectangular portions

131 a and 131 b, the bonded magnet 2 that is filled and molded at the outer peripheral end portion of the

rectangular portions

131 a and 131 b is more than the outer peripheral edge of the rotor core 1 by the cutout portion 14. It is arranged on the inner peripheral side, and is not easily demagnetized even by a reverse magnetic field applied from the stator S. Further, the projecting portion 15 not only defines the adjacent cutout portion 14, but the tip thereof constitutes a part of the outer peripheral edge of the rotor core 1. Thereby, the protrusion 15 constitutes a q-axis magnetic pole (a salient pole) and contributes to an increase in the reluctance torque of the synchronous motor SM.

(3) Bond magnet The bond magnet 2 is obtained by, for example, heating and melting pellets made of Nd—Fe—B based anisotropic magnet powder, Sm—Fe—N based magnet powder and polyphenylene sulfide resin (binder resin). The molten mixture is injection-filled into the slot 13. After this injection molding, the molten mixture is solidified in the slot 13 by cooling in the mold of the injection filling apparatus in a magnetic field, and the bond magnet 2 (permanent magnet) is integrally molded in the slot 13. In this way, the rotor R including the bonded magnet 2 having the same shape as the slot 13 is obtained. The bonded magnet 2 is not only oriented at the time of injection molding in a magnetic field, but is also magnetized at the same time, and is already in a state of exhibiting a high magnetic flux density. For this reason, in this embodiment, there is no need to separately perform post-magnetization. In the case of this embodiment, the orientation magnetic field distribution during the injection molding in the slot 13 is also substantially uniform as shown in FIG. 1A.

(4) Motor The synchronous motor SM is obtained by rotatably disposing a rotor R in a stator S with a shaft (not shown) fitted in the shaft hole 11 and attached thereto. The synchronous motor SM generates a rotating magnetic field in the stator S by an inverter-controlled power source, so that the rotor R rotates in synchronization with the rotating magnetic field. In the synchronous motor SM according to the present embodiment, the inductance Lq1 in the q-axis direction shifted by π / 2 (electrical angle) from the d-axis direction is larger than the inductance Ld1 in the d-axis direction passing through the center of the bond magnet 2. Become. Therefore, not only the magnet torque Tm1 by the permanent magnet M1 but also the reluctance torque Tr1 based on the inductance difference (Lq1−Ld1) is generated in the synchronous motor SM in the same direction as the magnet torque Tm1. Therefore, the synchronous motor SM exhibits a larger output torque.

SM synchronous motor (internal magnet type synchronous machine)
S Stator R Rotor 1 Rotor core (main body)
13 slots (inner part)
2 Bond magnet

Claims

A plurality of enclosing portions, which are made of a substantially cylindrical or substantially cylindrical soft magnetic material, are concavely curved toward the outer peripheral side and extend in the direction of the rotation center axis, around the rotation center axis The main body being
A permanent magnet made of a rare earth bonded magnet filled and molded in the inner packet part,
A rotor of an internal magnet type synchronous machine comprising:
The inner packet part extends in the direction of the rotation center axis in a section from the outer peripheral end closest to the outer peripheral edge of the main body to the inner peripheral end closest to the rotation central axis of the main body, and is a flat inner A rotor of an internal magnet type synchronous machine having a rectangular portion made of a wall surface.
2. The rotor of an internal magnet type synchronous machine according to claim 1, wherein each of the internal packet portions includes a plurality of the rectangular portions and a connection portion that connects between the adjacent rectangular portions.
The rotor of an internal magnet type synchronous machine according to claim 1 or 2, wherein the main body has an open groove portion that opens to an outer peripheral edge side of the inner packet portion and extends in the direction of the rotation center axis.
The rotor according to any one of claims 1 to 3,
A stator having a coil disposed on the outer periphery of the rotor and a yoke constituting a magnetic circuit on the outer peripheral side of the coil;
An internal magnet type synchronous machine comprising: