JP2016195494A - Manufacturing apparatus and manufacturing method of outer rotor for internal magnet type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the magnetic field of a bonded magnet emitted to fill the internal part of a non-closed annular yoke block obtained by dividing an outer rotor.SOLUTION: A manufacturing apparatus of the outer rotor of an internal magnet synchronous machine including an annular outer yoke composed of a soft magnetic material surrounding an inner stator consisting of an armature and rotatable for the inner stator, and a permanent magnet consisting of an anisotropic bonded magnet embedded in the internal part consisting of a cavity formed in the outer yoke is disclosed. The outer yoke is a closed annular body where yoke blocks, including a plurality of unit yokes coupled in a non-closed ring, are connected. The manufacturing apparatus includes at least one dummy yoke disposed on the circumferential end side of the yoke block, a plurality of orientation yokes located on the inner peripheral side of the yoke block and dummy yoke, and extending in the radial direction, and a plurality of orientation magnets sandwiching an adjoining orientation yoke from the opposite side in the circumferential direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus for manufacturing an inner rotor for an internal magnet type motor including an anisotropic bonded magnet, and a method for manufacturing the same.

  An internal magnet type motor (hereinafter referred to as an IPM motor) in which a permanent magnet is embedded in the rotor has a higher torque and a higher torque than a surface magnet type motor (SPM motor) in which a permanent magnet is bonded to the outer peripheral surface of the rotor. Because of its efficiency, it is used in motors for home appliances used in drive motors, washing machines, air conditioners, refrigerators, etc. for hybrid vehicles and electric vehicles that require high output performance.

  In Patent Document 1, the closed ring outer rotor of the IPM motor is divided into non-closed ring yoke blocks including six unit yokes connected to each other, and an anisotropic bond is formed on the inner portion of each unit yoke in an orientation magnetic field. Techniques for filling and forming magnets are disclosed. In the present specification, the term “closed ring” refers to a state in which the circumferential end surfaces of one or more yoke blocks are in close contact with each other to form a ring. Conversely, the “non-closed ring” refers to a state in which such a closed ring is not formed, that is, a state in which the circumferential end surfaces of the yoke block are not in close contact. Of course, when the yoke block is linear or curved, for example, a substantially annular shape such as a C-shape or a state where an open end surface is provided at one place corresponds to the closed annular shape in this specification. In the present specification, the closed ring may be simply referred to as “annular” and the non-closed ring may be simply referred to as “non-annular” for the sake of convenience unless confusion arises from the context. In Patent Document 1, each of the divided non-closed yoke blocks is arranged in a rear annular shape that is inverted so that the inner stator side becomes the outer peripheral side, and an anisotropic bond is formed from the outer peripheral side to the inner packet part of each unit yoke. The magnet is filled. After the anisotropic bonded magnet is filled, the yoke blocks are connected to form a closed annular outer rotor.

JP 2014-192980 A

  When the yoke block is annularly arranged on the back surface as in Patent Document 1, the orientation magnetic field can be increased because the degree of freedom in shape of the orientation magnet is widened. However, when a bonded magnet is filled and molded with the yoke block arranged in a ring shape on the back surface, man-hours are increased and it is not always efficient.

  Further, depending on the specifications of the motor, it may be sufficient to supply the orientation magnetic field with the orientation magnet arranged in an annular shape.

  The present invention has been made in view of the above-described circumstances, and the yoke block in which the outer rotor is divided is left in a non-closed ring shape without disposing the annular ring on the back side, and an anisotropic magnetic field is applied while applying an orientation magnetic field to the inner packet part. An object of the present invention is to provide an outer rotor manufacturing apparatus capable of obtaining an outer rotor exhibiting high characteristics by filling and forming a conductive bonded magnet, and a manufacturing method thereof.

  The present inventor has intensively studied to solve this problem. First, when an orientation magnetic field is applied while the yoke block obtained by dividing the outer rotor is left in a non-closed annular shape, the circumferential direction of the yoke block (unit yoke connection direction) It was newly found that the orientation magnetic field tends to be disturbed at both end portions (open end portions), and the magnetic field acting on the unit yoke located on the end portion side tends to decrease. Note that an imbalance in the orientation magnetic field between the unit yokes is not preferable because it causes a reduction in motor performance (a reduction in torque, generation of cogging torque, etc.).

  In view of this, the present inventor has conceived that a dummy yoke is disposed at the end of the yoke block in the circumferential direction (unit yoke connection direction). Then, it was confirmed that by applying an alignment magnetic field integrally to the yoke block and the dummy yoke, the alignment magnetic field imbalance generated between the unit yokes can be reduced or eliminated. By developing this result, the present invention described below has been completed.

  First, an apparatus for manufacturing an outer rotor of an internal magnet synchronous machine according to the present invention includes an annular outer yoke made of a soft magnetic material that surrounds an inner stator made of an armature and can rotate with respect to the inner stator, and the outer yoke. And a permanent magnet made of an anisotropic bonded magnet embedded in an inner packet part made of a gap. The outer yoke is a closed ring body in which a yoke block including a plurality of unit yokes connected in a non-closed ring shape is connected. The manufacturing apparatus includes at least one dummy yoke disposed on a circumferential end side of the yoke block, a plurality of alignment yokes extending radially in the inner circumferential side of the yoke block and the dummy yoke, and adjacent to the yoke block. And an orientation portion having a plurality of orientation magnets that sandwich the orientation yoke from both sides in the circumferential direction.

  The manufacturing apparatus of the present invention includes dummy yokes arranged at least one on each circumferential end (and both ends) of the yoke block, and an orientation magnetic field is applied integrally to the yoke block and the dummy yoke by the orientation portion. Is done. As a result, an orientation magnetic field substantially the same as that of the unit yoke on the center side is applied to the unit yoke on the circumferential end side of the yoke block, thereby reducing or eliminating the imbalance of the orientation magnetic field between the unit yokes. Can be done. Therefore, when the manufacturing apparatus of the present invention is used, the characteristics of the anisotropic bonded magnet filled and molded in each inner part of the yoke block can be made uniform, and an outer rotor with excellent characteristics, and thus an IPM motor can be efficiently obtained. it can.

  In the manufacturing apparatus according to the aspect of the invention, it is preferable that at least three dummy yokes are disposed on both ends of the yoke block in the circumferential direction. The magnetic field imbalance for each unit yoke in the yoke block can be suppressed more reliably.

  Next, in the manufacturing method of the present invention, the inner stator made up of an annular outer yoke made of a soft magnetic material that surrounds the inner stator made of an armature and can rotate with respect to the inner stator, and an air gap formed in the outer yoke. It is a manufacturing method of the outer rotor of an internal magnet synchronous machine provided with the embedded permanent magnet. The outer yoke is a closed ring body in which a yoke block including a plurality of unit yokes connected in a non-closed ring shape is connected. The manufacturing method includes a cavity in which the non-closed annular yoke block is disposed, a dummy yoke disposed at least one on the circumferential end side of the cavity, and an inner circumferential side of the cavity and the dummy yoke in a radial direction. An arrangement step of arranging the yoke block in the cavity of an orientation mold comprising a plurality of orientation yokes extending to the orientation mold and an orientation portion having a plurality of orientation magnets sandwiching the orientation yoke adjacent from both sides in the circumferential direction; An injection molding process for forming an anisotropic bonded magnet that becomes the permanent magnet by injecting and filling a molten mixture in which anisotropic magnet particles are dispersed in a molten binder resin into the inner portion of the yoke block in an orientation magnetic field And comprising.

  According to the manufacturing method of the present invention, similarly to the manufacturing apparatus of the present invention, a stable magnetic field can be obtained regardless of the position of the unit yoke in the yoke block. In the manufacturing method of the present invention, it is preferable that at least three dummy yokes are arranged on both ends in the circumferential direction of the yoke block. It is possible to more reliably suppress the magnetic field unbalance for each unit yoke in the yoke block.

  The details of the injection molding process are not limited. For example, injection molding may be performed on the inner part of each unit yoke for each single yoke block, or injection is performed by applying an orientation magnetic field with a plurality of yoke blocks connected and dummy yokes arranged on both ends thereof. Molding may be performed. The dummy yoke has substantially the same shape as that of the single or plural unit yokes, but the inner part may be left as a gap, or the inner part may already be filled with an anisotropic bonded magnet or the like.

  In the manufacturing method described above, a step of arranging the yoke blocks molded in a magnetic field in a closed ring may be performed. In the connecting step, for example, the end faces in the circumferential direction of the unit yokes located at both ends of the yoke block after injection molding may be brought into close contact with each other to form a closed ring, or the yoke block after injection molding is formed into an annular casing ( A closed ring may be formed by press-fitting into a ring case made of a soft magnetic material. In addition, the outer yoke after injection molding may be somewhat plastically deformed as appropriate during the disposing step.

  In this specification, unless the object or target portion is relatively viewed, the side near the rotation center of the outer rotor (inner stator side) is referred to as the “inner stator side”, and conversely from the rotation center. The far side is called “outer side”.

  Further, in this specification, the fact that a plurality of components are integrally formed at least partially and connected to each other is referred to as “connecting”, and the installation of a plurality of components completely separated from each other is referred to as “connecting”. "It will be installed." Note that “connecting” includes an integrated state without a break as a whole.

It is a figure which shows a part of outer rotor manufactured by the manufacturing apparatus or manufacturing method which concerns on an Example. It is the figure which installed the yoke block which divided | segmented the outer rotor shown in FIG. 1 in the manufacturing apparatus (orientation metal mold | die) which concerns on an Example. It is a figure which shows the groove part provided in the circumferential direction end surface of the yoke block shown in FIG. FIG. 3 is an enlarged view of an orientation portion in the vicinity of the yoke block of FIG. 2. It is a figure which shows the relationship between the position of the unit yoke in a yoke block and a dummy yoke, and an orientation magnetic field. It is a figure which shows a part of yoke block which divided | segmented the outer rotor which concerns on a modification.

  The contents disclosed in the present specification can be applied not only to the outer rotor but also to an internal magnet type motor using the outer rotor. Matters related to the manufacturing method can also be components related to products if understood as product-by-process. One or more arbitrarily selected from the matters described in the present specification may 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.

  Unless otherwise specified, the internal magnet type motor referred to in this specification includes a generator. Further, the internal magnet type motor of the present specification includes an original motor whose rotational speed changes in synchronization with the frequency of an alternating current supplied to a coil (armature winding) provided in a stator (inner 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 (outer rotor) detected by detection means such as a Hall element, a rotary encoder, or a resolver. Incidentally, since the brushless DC motor can change the rotation speed by changing the DC voltage supplied to the inverter, it is excellent in controllability like a normal DC motor.

  The internal magnet type motor disclosed in the present specification may be used for any purpose. For example, a motor for home appliances used in a washing machine, an air conditioner, a refrigerator, or the like, or a vehicle used in an electric vehicle, a hybrid vehicle, a railway vehicle, or the like It is suitable for a drive motor. In particular, the motor of the present invention is suitable as a direct drive motor (DD motor) that simultaneously requires high output, low vibration, low noise, and the like.

《Outer rotor of internal magnet type motor》
(1) Yoke block The yoke block constituting the skeleton of the outer rotor is made of a soft magnetic material, and usually pressurizes a laminate of electromagnetic steel sheets with insulation coating on both sides or soft magnetic powder made of insulation coated metal particles. It consists of a molded dust core. The soft magnetic material may be any material, but is preferably an iron-based material such as pure iron, silicon steel, or alloy steel. The yoke block includes a plurality of unit yokes connected in a non-closed ring shape. Adjacent unit yokes may be connected to each other in the radial direction, or only a part of the unit yokes may be connected and may be separated from each other.

  The yoke block is produced by punching out a silicon steel plate whose surface is insulated and laminating the plate-like members in units of yaw blocks. In order to improve the yield at the time of punching, when having a structure in which a plurality of unit yokes are connected by a bridging portion or the like, some plastic deformation may be required during the connecting process of connecting the yoke blocks. In such a case, the soft magnetic material is preferably a ductile material (specifically, a laminate of electromagnetic steel sheets). In addition, when a plurality of unit yokes are arranged in an annular shape to form an annular yoke block, an engaging portion or a fitting portion such as a concavo-convex portion, a notch, or a guide is provided in the vicinity of the circumferential end surface where adjacent unit yokes contact each other. If it is provided, the connecting step can be performed efficiently. The number of each yoke block constituting the outer yoke can be arbitrarily selected. For example, an outer rotor may be configured by connecting yoke blocks including the same number of unit yokes as in the embodiments described later, or by connecting yoke blocks including different unit yokes. It may be configured. When an outer rotor is configured by connecting yoke blocks including the same number of unit yokes, the outer rotor can be manufactured using the same orientation mold (which is an example of a manufacturing apparatus disclosed in the present specification). It is preferable in that it can be performed.

(2) Inner part The inner part consists of a gap provided at least one for each unit yoke. By forming a rare earth anisotropic bonded magnet in the magnetic field on the inner part, one magnetic pole of the outer rotor is formed for each unit yoke.

  Regardless of the form of the inner packet part, it is appropriately adjusted according to the specifications of the motor. For example, the inner packet part may be arc-shaped, U-shaped, curved, V-shaped, linear, or the like. Further, when the inner packet part is curved, it is preferable that the open end of the inner packet part is on the inner peripheral side (inner stator side) because the motor can be improved in performance. In addition, it is preferable that the inner envelope portion has a smooth curved shape (for example, an arc shape) having a uniform groove width because a high orientation magnetic field can be uniformly applied to the entire inner envelope portion. The inner packet part can be normally formed continuously in each unit yoke, but may be in a divided state according to the specifications of the outer rotor. The inner packet part may be provided in multiple (or multiple layers) within the unit yoke. Furthermore, a low magnetic part having a low magnetic permeability may be provided in the inner packet part to control the strength and direction of the orientation magnetic field.

《Dummy York》
As the material of the dummy yoke, a soft magnetic material is used, and iron-based materials such as pure iron, silicon steel, and alloy steel can be particularly preferably used. The material of the dummy yoke is preferably the same as the material of the yoke block. The shape of the dummy yoke is preferably the same as the shape of the unit yoke of the yoke block.

<Rare earth anisotropic bonded magnet>
(1) Raw material A rare earth anisotropic bonded magnet basically comprises a rare earth anisotropic magnet powder and a binder resin. The type of rare earth anisotropic magnet powder is not limited, and examples thereof include Nd—Fe—B magnet powder, Sm—Fe—N magnet powder, and Sm—Co magnet powder. The rare earth anisotropic magnet powder according to the present invention may be one kind or plural kinds. 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, a combination of coarse powder and fine powder of Nd-Fe-B magnet powder or a combination of coarse powder of Nd-Fe-B magnet powder and fine powder of Sm-Fe-N magnet powder may be used. By using such rare earth anisotropic 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. Furthermore, various isotropic magnet powders, ferrite magnet powders, and the like may be mixed in the rare earth anisotropic magnet powder.

  Various materials including rubber can be used for the binder resin. 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. You can also.

(2) Injection molding After the molten mixture obtained by heating and melting the pellets made of the above raw material is injected and filled into the inclusion part to which the orientation magnetic field is applied, it is cooled and solidified, so that the rare earth anisotropic according to the form of the inclusion part A bonded magnet is formed. Each condition of the injection molding is appropriately adjusted in consideration of the characteristics of the raw material, the filling amount, the cooling property of the inner packet part, and the like. The orientation magnetic field needs to be applied before the molten mixture is solidified, but may start from the beginning of injection molding or from the middle of injection molding. For example, when a permanent magnet is used as the orientation magnetic field source, it may be from the beginning of injection molding. Note that, in the manufacturing method disclosed in this specification, a sufficiently high orientation magnetic field can be applied to the inner portion of the unit yoke, so it does not matter whether there is magnetization after the injection molding process. Moreover, in the manufacturing method of this specification, you may magnetize separately in the step which performs a demagnetization process before the arrangement | positioning process after an injection molding process, and is set as the cyclic | annular outer rotor.

  The application mode of the orientation magnetic field (distribution of magnetic flux density formed in the outer rotor) is appropriately adjusted according to the shape of the inner packet part and the specification of the motor. An electromagnet may be used as the orientation magnetic field source, but it is preferable to use a strong permanent magnet (rare earth magnet) in order to save energy and make the orientation mold and the injection molding apparatus compact.

《Outer rotor of internal magnet type motor》
FIG. 1 is a view showing a part of an outer rotor R used in a direct drive motor (which is an example of an internal magnet motor). The outer rotor R is molded in a magnetic field into an annular case C, 48 unit yokes P press-fitted on the inner peripheral side of the case C, and a semicircular arc-shaped inner portion k provided in each unit yoke P. And a permanent magnet m made of a rare earth anisotropic bonded magnet. The case C and the unit yoke P are made of laminated electromagnetic steel sheets punched into a predetermined shape.

  The outer rotor R includes four yoke blocks in which 12 unit yokes P are connected to each other, and includes 48 unit yokes that are connected or arranged in series as a whole. In each yoke block, adjacent unit yokes P are entirely connected to each other in the circumferential direction. Four yoke blocks in the yoke block are connected in a state of being fitted in the case C to form a series of closed annular outer rotors R.

  FIG. 2 shows a state in which the yoke block L1 is arranged in an orientation mold D (an example of an outer rotor manufacturing apparatus disclosed in this specification) of an injection molding apparatus. The orientation mold D is for a yoke block having 12 poles. The alignment mold D includes an alignment portion D1, a pair of dummy alignment portions D2 disposed on both ends in the circumferential direction of the alignment portion D1, and a pair of dummy yokes Ld1 corresponding to the pair of dummy alignment portions D2. Ld3. The orientation portion D1 includes 12 orientation yokes Dy extending in the radial direction (r-axis direction shown in FIG. 2) and 12 pairs (24) orientation magnets that sandwich the adjacent orientation yokes Dy from both sides in the circumferential direction. Dm. One orientation yoke Dy and two orientation magnets Dm adjacent to the orientation yoke Dy constitute one set and constitute one pole of the orientation portion. Each dummy orientation portion D2 includes three pairs (six) of three dummy orientation yokes Dd1 to Dd3 extending in the radial direction and the dummy orientation yokes Dd1 to Dd3 adjacent to each other from both sides in the circumferential direction. Dummy orientation magnets Dn1 to Dn3 are provided. The dummy alignment yokes Dd1 to Dd3 are arranged in the order of Dd1, Dd2, and Dd3 from the side close to the alignment portion D1. The inner peripheral surfaces of the dummy yokes Ld1, Ld2, and Ld3 face the outer peripheral surfaces of the corresponding dummy alignment yokes Dd1, Dd2, and Dd3 and the dummy alignment magnets Dn1 to Dn3, respectively.

  The dummy yokes Ld1 to Ld3 are made of laminated electromagnetic steel plates made of the same material as the unit yokes of the yoke block L1, and are formed in the same shape. The orientation yoke Dy and the dummy orientation yokes Dd1 to Dd3 are soft magnetic bodies made of general structural rolled steel SS440 (JIS G3101), and all 18 pieces have the same shape. The orientation magnet Dm and the dummy orientation magnets Dn1 to Dn3 are permanent magnets made of an Nd—Fe—B rare earth anisotropic sintered magnet, and all 36 pieces have the same shape.

  A cavity X for disposing the yoke block L1 is formed along the outer peripheral surface of the orientation portion D1 of the orientation mold D. When the yoke block L1 is disposed in the cavity X, the inner peripheral surfaces of the twelve unit yokes P included in the yoke block L1 face the outer peripheral surfaces of the 12 sets of the orientation yokes Dy and the orientation magnets Dm. As shown in FIG. 3, one circumferential end E1 of the yoke block L1 includes a convex coupling portion E11 and a linear end surface E12, and the other circumferential end E2 is a concave coupling. A portion E21 and a linear end surface E22 are provided. When connecting the two yoke blocks L1, the end surface E12 of one yoke block L1 and the end surface E22 of the other yoke block L1 are brought into close contact with each other, and the convex coupling portion E11 is fitted into the concave coupling portion E21.

  An orientation magnetic field is applied to the yoke block L1 by the orientation part D1, and an orientation magnetic field is applied to the dummy yokes Ld1 to Ld3 by the orientation part D2. FIG. 4 is an enlarged view of the orientation portion D1 in the vicinity of the yoke block L1 in FIG. The arrows shown in FIG. 4 indicate the direction of the orientation magnetic field. 2 and 4, the anisotropic bonded magnet is injection-molded (molded in a magnetic field) only on the yoke block L1 in an orientation magnetic field (injection molding process). As a result, the molten mixture of the binder resin and the rare earth anisotropic magnet powder is injected and filled into the inclusion part k in an orientation magnetic field. Then, the rare earth anisotropic magnet particles are cooled and solidified after being oriented (changed in posture) in a desired direction along the orientation magnetic field. Thus, the yoke block L1 including the permanent magnet m made of the rare earth anisotropic bonded magnet oriented in the desired direction is obtained.

  In this example, a mixed magnet powder of Nd—Fe—B type anisotropic magnet powder and Sm—Fe—N type magnet powder was used as the rare earth anisotropic magnet powder. Moreover, polyphenylene sulfide resin was used as binder resin. The injection-molded molten mixture is obtained by heating and melting pellets made of the mixed magnet powder and a binder resin.

  The yoke block L1 after being molded in the magnetic field is taken out from the orientation mold D and is inserted into the annular case C so as to have a shape along the outer rotor R. The four yoke blocks L1 are manufactured by the same process described above. Between two adjacent yoke blocks L1, the end surface E12 of one yoke block L1 and the end surface E22 of the other yoke block L1 are brought into close contact with each other, and the convex coupling portion E11 of one yoke block L1 is connected to the other yoke block L1. Is inserted into the concave coupling portion E21, and the four yoke blocks L1 are connected to form a closed annular body, thereby forming an annular outer yoke filled with bond magnets. By inserting the annular outer yoke into the case C, the outer rotor R is completed.

<< Relationship between unit yoke position and magnetic field >>
Similar to the orientation mold D, or has the same form as the orientation mold D except that the number of dummy orientation yokes and dummy orientation magnets included in the dummy yoke (Ld) and the dummy orientation portion D2 is different. Using an orientation mold for calculation, the orientation magnetic field distribution of each unit yoke P was examined by simulation using a two-dimensional static magnetic field method. For example, in the case of using three dummy yokes, the simulation is performed with six unit yokes (Ls1) arranged on the circumferential end side on one side from the center of the 12 poles of the yoke block L1 arranged facing the orientation portion D1. To Ls6) and the dummy yokes (Ld1 to Ld3) that are placed facing the dummy orientation portion D2 disposed on the circumferential end side. In the simulation, oriented magnet and dummy oriented magnet: Nd-Fe-B series magnet NMX33UH (manufactured by Hitachi Metals), yoke block and dummy yoke: electromagnetic steel sheet 50H1300 (manufactured by Nippon Steel & Sumikin Co., Ltd.), oriented yoke and dummy oriented yoke: Rolling steel for general structure SS440 (JIS G3101) was used as the material.

(Comparison calculation example)
A 12-pole orientation mold for calculation different from the orientation mold D of FIG. 2 in that the dummy yoke (Ld) and the dummy orientation portion D2 are not included (the number of pairs of dummy orientation yokes and dummy orientation magnets is zero). Was used to calculate the orientation magnetic fields of the six unit yokes (Ls1 to Ls6) arranged in the circumferential direction on one side from the center of the 12 poles of the yoke block L1 arranged to face the orientation part D1. In addition, the value of the orientation magnetic field uses the average value of the orientation magnetic field in the cross section of the inner envelope k (the cross section in the direction parallel to the paper surface of FIG. 2).

(Calculation Example 1)
Each of the dummy orientation portions D2 includes only one pair of dummy orientation yokes Dd1 and a pair of dummy orientation magnets Dn1, and the dummy orientation portions D2 are positioned adjacent to Ls6 located on the outermost end side in the circumferential direction of the yoke block L1. A 14-pole orientation mold for calculation, which is different from the orientation mold D in FIG. 2 in that only one dummy yoke Ld1 is arranged facing each other, is arranged on one side from the center of the 12 poles of the yoke block L1. The orientation magnetic fields of the six unit yokes (Ls1 to Ls6) arranged in the circumferential direction and the orientation magnetic field of the dummy yoke Ld1 were calculated.

(Calculation Example 2)
Using the 18-pole calculation orientation mold similar to the orientation mold D, the orientation magnetic fields of the six unit yokes (Ls1 to Ls6) arranged in the circumferential direction on one side from the center of the 12 poles of the yoke block L1. , And the dummy magnetic fields Ld1 to Ld3 were calculated.

  The results of the comparative calculation example and calculation examples 1 and 2 are shown in FIG. In FIG. 5, the white square symbol and the alternate long and short dash line indicate the orientation magnetic field distribution of the comparative calculation example (the triangle symbol and the broken line indicate the orientation magnetic field distribution of the calculation example 1, and the black square symbol and the solid line indicate 5 shows the orientation magnetic field distribution of Calculation Example 2. The horizontal axis in FIG.5 is the inner packet number, and the unit yoke P located closest to the center in the circumferential direction of the yoke block L1 (the connecting direction of the unit yokes P) is shown. The inner packet part number of the inner packet part k is 1, and the number increases toward the end in the circumferential direction, and the yoke block L1 will be described with reference to the unit yokes Ls1, Ls2, and Ls3. , Ls4, Ls5, and Ls6 are given the inclusion numbers 1, 2, 3, 4, 5, and 6 in this order, and the dummy yokes Ld1, Ld2, and Ld3 have the inclusion numbers 7, 8, and 9 in this order. Granted That.

  As shown in FIG. 5, in the case of the comparative calculation example (only in the case of the yoke block L1), the magnetic field of the orientation magnetic field is remarkably reduced at the inclusion part number 6. The inner part number is a number assigned to the inner part of the unit yoke Ls6 located on the endmost side of the yoke block L1, and the magnetic field is remarkably reduced in the unit yoke P located on the endmost side. I understood. In addition, the unit yokes Ls4 and 5 with the inner part numbers 4 and 5 have larger magnetic field fluctuations than the unit yokes Ls1 to Ls3 with the inner part numbers 1 to 3, and the third from the endmost side of the yoke block L1. In the unit yoke Ls4 (inner part number 4) located, the magnetic field decreases, and in the unit yoke Ls5 (inner part number 5) located second from the endmost side of the yoke block L1, the magnetic field greatly increases. all right.

  On the other hand, in the calculation examples 1 and 2, a sufficient orientation magnetic field is obtained by the unit yoke Ls6 having the inner part number 6 located on the endmost side of the yoke block L1. On the other hand, in Calculation Example 1, in the dummy yoke Dd1 (including part number 7) adjacent to the unit yoke Ls6 of the yoke block L1, the magnetic field is significantly reduced as in the unit yoke Ls6 in the comparative calculation example. In addition, the unit yokes Ls5 and 6 of the inner packet part numbers 5 and 6 have a larger magnetic field fluctuation than the unit yokes Ls1 to Ls4 of the inner packet part numbers 1 to 4. That is, in the case of Calculation Example 1, a significant decrease in the orientation magnetic field at the end of the yoke block L1 is prevented. However, the magnetic field distribution varies in the vicinity of the end of the yoke block L1.

  In Calculation Example 2, the magnetic field is extremely large in the dummy yoke Dd3 (including part number 9) arranged farthest from the yoke block L1, as in the unit yoke Ls6 (including part number 6) in the comparative calculation example. It is falling. Compared with the unit yokes Ls1 to Ls6 of the inner part numbers 1 to 6 belonging to the yoke block L1, the dummy yokes Dd1 and Dd2 of the inner part numbers 7 and 8 have a sufficient orientation magnetic field, but a magnetic field is obtained. The fluctuation of is large. That is, in the calculation example 2, a significant decrease in the orientation magnetic field at the end of the yoke block L1 is prevented, and fluctuations in the magnetic field distribution in the vicinity of the end of the yoke block L1 are also suppressed.

  That is, when the yoke block L1 obtained by subdividing the closed annular outer rotor R is used in the non-closed annular state and the inner portion k is filled with an anisotropic bonded magnet and molded, the yoke block used for the molding is It has been found that by disposing one or more dummy yokes on both ends, it is possible to prevent a significant decrease in magnetic field that can occur on both ends of the yoke block and to obtain a sufficient orientation magnetic field. Further, it was found that the disturbance of the orientation magnetic field can be further suppressed by using three or more dummy yokes disposed on both ends of the yoke block L1 used for the molding.

  The yoke block may be such that adjacent unit yokes are connected only at a part thereof, as in a yoke block L11 shown in FIG. In the yoke block L11, the unit yokes P11 divided in a substantially fan shape by the slits s are connected by a bridging portion a. The bridging portion a is provided on the outer peripheral side of the unit yoke P (the outer peripheral surface fo side shown in FIG. 6), and can easily be plastically deformed on the outer peripheral side to open the slit s. Since the yoke block L11 can be punched from the laminated electromagnetic steel sheet in a state where the unit yokes P are substantially linear with each other, the laminated electromagnetic steel sheet can be used with a high yield.

R: outer rotor L1: yoke block P: unit yoke C: case D: orientation mold D1: orientation portion D2: dummy orientation portion Dd1-Dd3: dummy orientation yoke Dm: orientation magnet Dn1-Dn3: dummy orientation magnet Dy: orientation Yoke Ld1 to Ld3: Dummy yokes Ls1 to Ls6: Unit yoke X: Cavity a: Bridge portion m: Permanent magnet k: Inclusion portion s: Slit

Claims (4)

An annular outer yoke made of a soft magnetic material surrounding an inner stator made of an armature and capable of rotating with respect to the inner stator, and an anisotropic bonded magnet embedded in an inner packet portion formed by a gap formed in the outer yoke An apparatus for manufacturing an outer rotor of an internal magnet synchronous machine including a permanent magnet,
The outer yoke is a closed annular body in which a yoke block including a plurality of unit yokes connected in a non-closed annular shape is connected,
At least one dummy yoke disposed on the circumferential end side of the yoke block;
A plurality of orientation yokes extending radially in the inner peripheral side of the yoke block and the dummy yoke;
An orientation portion having a plurality of orientation magnets sandwiching the orientation yoke adjacent from both sides in the circumferential direction;
An outer rotor manufacturing apparatus comprising:   2. The outer rotor manufacturing apparatus according to claim 1, wherein at least three of the dummy yokes are disposed on both ends of the yoke block in the circumferential direction. An inner envelope comprising an annular outer yoke made of a soft magnetic material that surrounds an inner stator made of an armature and can rotate with respect to the inner stator, and a permanent magnet embedded in an inner packet portion formed by a gap formed in the outer yoke. A method of manufacturing an outer rotor of a magnet synchronous machine,
The outer yoke is a closed annular body in which a yoke block including a plurality of unit yokes connected in a non-closed annular shape is connected,
A cavity in which the non-closed annular yoke block is disposed, a dummy yoke disposed at least one on the circumferential end side of the cavity, and a plurality of radially extending radial cavities on the inner circumferential side of the cavity and the dummy yoke An arranging step of arranging the yoke block in the cavity of an orientation mold comprising an orientation portion having an orientation yoke and a plurality of orientation magnets sandwiching the orientation yoke adjacent from both sides in the circumferential direction;
An injection molding step of forming an anisotropic bonded magnet that becomes the permanent magnet by injecting and filling a molten mixture in which anisotropic magnet particles are dispersed in a molten binder resin into an inner portion of the yoke block in an orientation magnetic field; ,
An outer rotor manufacturing method comprising:   The outer rotor manufacturing method according to claim 3, wherein at least three dummy yokes are arranged at both ends of the yoke block in the connecting direction.

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