JP2017034765A - Manufacturing device for magnet-inclusion type rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device for a magnet-inclusion type rotor capable of obtaining a high-precision rotor in which slots are filled with anisotropic bond magnets at a high orientation degree.SOLUTION: A manufacturing device for a magnet-inclusion type rotor is configured to obtain the magnet-inclusion type rotor comprising magnetic poles consisting of anisotropic bond magnets in which a plurality of slots (12) disposed around an axis of a rotor core (1) are filled with a floating mixture that is a mixture of a binder resin and anisotropic magnet particles, and the floating mixture is solidified. The manufacturing device comprises: a movable-side metal mold (5) disposed at a movable side of an injection molding machine and capable of supporting another end side of the rotor core; and stationary-side metal molds (6 and 7) constituting a flow passage of the floating mixture. The stationary-side metal mold further includes an orientation part for applying an orientation magnetic field to the slots of the rotor core accommodated insides. By performing injection molding with the metal molds, the flow passage for the floating mixture can be shortened and a high-precision IPM rotor in which the slots are filled with high-orientation bond magnets can be obtained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for manufacturing an internal magnet type rotor using an anisotropic bonded magnet as a magnetic pole.

  There are various types of electric 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 achieve power saving, high efficiency, high torque or high output.

  A synchronous motor is a motor having a permanent magnet in a rotor (rotor) and an armature winding (coil) in a stator (stator), and supplying alternating current (AC) to the armature winding. This is an AC motor that drives the rotor by generating a rotating magnetic field in the stator. In the synchronous machine, a surface magnet type motor (also referred to as “SPM motor”) in which a permanent magnet is disposed on the surface of the rotor, and the permanent magnet is disposed in the rotor. There is a built-in (implanted) magnet type motor (Interior Permanent Magnet Synchronous Motor / also simply referred to as “IPM motor” or “motor”). At present, not only high torque and power saving, but also IPM motors that can improve reliability by preventing scattering of permanent magnets are becoming mainstream.

  In conventional IPM motors, an internal magnet type rotor in which magnetic poles are formed by inserting rare earth sintered magnets cut or polished to a predetermined size into slots of the rotor core has been used. However, when optimizing an IPM motor, the shape of the permanent magnet contained in the rotor is substantially arc-shaped or substantially elliptical, the inner side surface and the outer side surface have different radii, the magnet thickness Often changes in the circumferential direction. Therefore, as a permanent magnet constituting the magnetic pole of the encapsulated magnet type rotor (appropriately referred to as “IPM rotor” or simply “rotor”), the shape can be freely replaced with a sintered magnet having a small degree of freedom in shape and easily causing defects. Rare earth anisotropic bonded magnets (which are also simply referred to as “bonded magnets”), which have a high degree of productivity and excellent productivity, have come to be used. Such a bonded magnet is formed by injecting a fluid mixture of rare earth anisotropic magnet particles (powder) and a binder resin into a slot in an orientation magnetic field. There is a description related to this in Patent Document 1 below.

JP 2003-47212 A

  In Patent Document 1, a rotor core is accommodated on the inner peripheral side of an orientation device (lower mold) having permanent magnets and pole pieces arranged on the outer peripheral side, and resin magnets (bond magnets) are filled into the slits of the rotor core. Manufactures IPM rotors. At this time, the flow path from the outlet of the nozzle of the injection molding machine (simply referred to as “injection nozzle”) to the slit of the rotor core is formed by an intermediate mold and an upper mold stacked on the lower mold. Specifically, the upper mold is formed with an inlet (primary sprue) connected to the outlet of the injection nozzle, and the intermediate mold is connected to the downstream side of the upper mold inlet in the lateral direction (shaft). A runner extending in the direction perpendicular to the direction), a secondary sprue with a reduced diameter extending further in the orthogonal direction (axial direction) from the downstream side of the runner, and a gate (pin gate) formed at the tip thereof. Yes.

  When such a mold of Patent Document 1 is attached to an injection molding machine, an upper mold and an intermediate mold that constitute a flow path are disposed on a fixed side where an injection nozzle is located, and receive a rotor core and apply an orientation magnetic field. The mold is disposed on the movable side. That is, the upper mold and the intermediate mold are fixed molds, and the lower mold is a movable mold.

  In FIG. 1 of Patent Document 1, the upper end surface (the end surface on the opening side) of the lower mold and the upper end surface of the rotor core accommodated therein are in a flush state. More specifically, a frame (14) made of a non-magnetic material, a pole piece (6) housed inside thereof and an orientation part made of a permanent magnet (5), and a rotor core housed inside thereof ( Each upper end surface of 1) is arranged in a flush state. In addition, the number in () is the code | symbol attached | subjected to FIG.

  However, in consideration of disturbance of the orientation magnetic field at the end portion, the orientation portion is normally set higher than the rotor core (the housing portion of the rotor core is deep) in order to uniformly apply the orientation magnetic field to the entire slit in the rotor core. Speaking of the lower mold of Patent Document 1, the upper end surface of the orientation portion (pole piece and permanent magnet) is higher than the upper end surface of the rotor core. Furthermore, in order to suppress the leakage magnetic field, a correspondingly thick nonmagnetic shielding plate is disposed on the end face side of the orientation portion.

  For this reason, from the upper end surface of the rotor core accommodated in the lower mold to the upper end surface of the lower mold (the lower end surface of the intermediate mold), the secondary sprue filled with the resin magnet is naturally considerably longer. There is a need to. Moreover, the flow path of the secondary sprue is generally quite thin. When the heat-melted resin magnet passes through such a long and narrow flow path, the amount of heat removed from the resin magnet to the mold is considerably increased. As a result, the resin magnet has a decrease in fluidity or increased viscosity, so that not only the fillability of the resin magnet but also the degree of orientation of the resin magnet filled in the slit can be significantly reduced.

  Here, when the injection pressure (speed) is increased in order to improve the filling property of the resin magnet, the rotor core is easily deformed, and it is difficult to ensure the accuracy of the rotor and hence the performance of the IPM rotor. Further, even if the injection pressure is increased, the increase in the viscosity of the resin magnet cannot be suppressed, and a decrease in the degree of orientation of the resin magnet cannot be avoided. Further, the heating temperature of the resin magnet cannot be set to an excessively high temperature exceeding the Curie point, and such overheating is not efficient.

  Unlike injection molding of general resin products when bonding magnets (resin magnets) are injected into slots in the rotor core, the reason why such unique problems occur is, according to the inventor's research, It can be considered as follows. First, unlike a cavity formed by a robust mold, a slot of a rotor is formed by laminating electromagnetic steel plates punched into a desired shape, and often has a thin and low rigidity portion on the outer peripheral side. For this reason, if the injection pressure (speed) is easily increased in order to prevent poor filling or improve the filling efficiency, distortion (deterioration of roundness, cylindricity, etc.) occurs around the slot (especially on the outer periphery). ) May occur. Such a rotor causes a decrease in the performance of the IPM motor and causes vibration and noise.

  Next, in the case of simple injection molding of a resin product, the viscosity of the resin during filling does not become a significant problem unless appearance defects such as short shots and sink marks occur. However, when injection molding a bonded magnet, anisotropic magnet particles (also simply referred to as “magnet particles”) mixed in the molten resin are within a short period of time from filling the slot to solidifying. It is necessary to change the orientation (orientation) along the orientation magnetic field applied to the slot. At this time, if the fluid mixture (especially molten resin) has an excessively high viscosity, the orientation variation of the magnet particles becomes insufficient, and the orientation degree of the bonded magnet filled in the slot is lowered, and consequently the performance of the rotor or motor is lowered. Can be invited.

  Furthermore, a strong magnetic force acts on the magnet particles filled in the slot in a direction perpendicular to the flow direction (direction that hinders the flow), so that the viscosity of the whole fluid mixture in the slot (apparent) Viscosity) tends to be higher than the viscosity of the binder resin itself. For this reason, when the bonded magnet is injection-molded in the slot of the rotor core, the filling property and the fluidity are more likely to be lower than when a simple resin product is injection-molded.

  Based on such a situation, the present inventor devised the form of the fixed side mold while assuming the holding of the rotor core and the application of the orientation magnetic field with the movable side mold as in the conventional case. Considering shortening the length of the flow path (especially the secondary sprue) from the injection nozzle to the slot. An example of such a molding die D0 is shown in FIGS. 3A and 3B (both are simply referred to as “FIG. 3”). 3A shows the mold closed state, and FIG. 3B shows the mold open state.

  The molding die D0 is set and used in a general-purpose injection molding machine. The molding die D0 is a so-called three-plate die and has a three-layer structure of a base die 50, an orientation die 60, and an injection die 70. The base mold 50 and the orientation mold 60 constitute a movable mold that is attached to the movable side of the injection molding machine, and the injection mold 70 constitutes a fixed mold that is attached to the fixed side of the injection molding machine. .

  The base mold 50 is accommodated in the center of the mounting portion 510 attached to the movable side of the injection molding machine, the protruding distance securing portion 520 disposed on the mounting portion 510, and the protruding distance securing portion 520. And a protruding portion 530. One side (upper side in FIG. 3) of the protruding portion 530 has a columnar shape that is substantially the same diameter as the rotor core 1, and the shaft that is inserted into the shaft hole of the rotor core 1 from the front end portion (upper end surface side in FIG. 3). A portion 5310 protrudes. In other words, the front end side of the protrusion 530 has a stepped shape that can hold the rotor core 1.

  When the shaft hole of the rotor core 1 is inserted into the shaft portion 5310, the other end surface (lower end surface) of the rotor core 1 comes into contact with the stepped surface on the distal end side of the protruding portion 530. Thus, the rotor core 1 is held on the tip side of the protrusion 530. The protrusion 530 is made of a nonmagnetic material. Further, the forward / backward drive of the protrusion 530 is performed by a protrusion mechanism (actuator or the like) of an injection molding machine (not shown).

  The orientation mold 60 includes a base portion 610, a frame portion 620 disposed coaxially above the center of the base 610, a shielding ring 650 inscribed and accommodated in the frame portion 620, and inscribed in the frame portion 620. Shield plates 630 and 640 that are housed and are in contact with the upper and lower end surfaces of the shield ring 650, and an annular orientation magnetic field body 660 that is housed in a space formed by the shield plates 630 and 640 and the shield ring 650. . The shielding plates 630 and 640 and the shielding ring 650 are made of a nonmagnetic material. Further, the lower end surface of the frame portion 620 and the lower end surface of the shielding plate 630, and the upper end surface of the frame portion 620 and the upper end surface of the shielding plate 640 are in a flush state.

  The injection mold 70 is sandwiched between an annular base portion 710, a mounting portion 720, a concave portion provided near the center of the upper end side of the base portion 710, and a concave portion provided near the center of the lower end side of the mounting portion 720. A flow path section 730, a locating ring 740 that centers the injection nozzle and the mold, and a nozzle touch section 7311 that contacts the injection nozzle and prevents leakage of the fluid mixture. In addition, the flow path part 730 is divided | segmented into two members for discharge of the sprue runner which the fluid mixture solidified.

  In the center of the base portion 710, a nest 7110 having a runner portion 7120 and a secondary sprue portion 7131 is fitted. The runner portion 7120 has a substantially semicircular open cross section extending from the center on the upper end side toward the slot 12 of the rotor core 1 in the lateral direction. Secondary sprue portion 7131 extends in the axial direction from the downstream side of each runner portion 7120 to the opening of slot 12.

  The attachment portion 720 is fitted with a nest 735 having a primary sprue portion 7310 and a part of the runner portion 7320. The flow path part 730 has a primary sprue part 7310 and runner parts 7320 and 7321. The upstream end opening of the sprue portion 7310 is connected to the outlet of the injection nozzle. The runner portion 7320 has a substantially semicircular open groove with a cross section that extends uniformly in the lateral direction from the downstream end side of the primary sprue portion 7310, and faces the runner portion 7120 of the base portion 710. Form a runner.

  As shown in FIG. 3A, when the molding die D0 is closed and the bonded magnet is injection-molded, the rotor core 1 is arranged at the center in the axial direction of the orientation die 60 on the movable side. At this time, the upper end surface of the rotor core 1 is at a deep position from the lower end surface side (the upper end surface of the orientation mold 60) of the injection mold 70 (base portion 710) on the fixed side. Therefore, even when the improved molding die D0 is used, the secondary sprue portion 7131 provided in the injection die 70 on the fixed side is considerably long in the axial direction, and the fluidity of the fluid mixture in at least the secondary sprue is at least. Reduction or increase in viscosity was difficult to avoid.

  The present invention has been made in view of such circumstances, and the flow channel length of the fluid mixture injected into the slot of the rotor core is further shortened than before, and the degree of orientation of the bond magnet filled in the slot. It is an object of the present invention to provide an internal magnet type rotor manufacturing apparatus capable of suppressing a decrease and deformation of a rotor.

  As a result of extensive research and trial and error, the present inventor has conducted an alignment mold (orientation portion) that has been arranged on the movable side of the injection molding machine until now on the fixed side of the injection molding machine. It has been devised that by arranging it, the flow path length of the fluid mixture injected into the slot of the rotor core can be further shortened than before. By realizing and developing this idea, the present invention described below has been completed.

<Embedded magnet type rotor manufacturing equipment>
(1) The internal magnet type rotor manufacturing apparatus of the present invention (simply referred to as “manufacturing apparatus”) is heated and flowed into a slot which is a cavity that is disposed around the axis of the rotor core and has an opening at least at one end. An inner shell used for obtaining an inner magnet type rotor having a magnetic pole made of an anisotropic bonded magnet filled with a fluid mixture, which is a mixture of a binder resin and anisotropic magnet particles in a state, and solidifying the fluid mixture A magnet-type rotor manufacturing apparatus, which is disposed on the movable side of an injection molding machine and can support the other end of the rotor core, and the injection molding machine facing the movable side mold A fixed-side mold disposed on the fixed side, and the fixed-side mold accommodates the rotor core inserted from the other end side (one end side of the rotor core) and applies an orientation magnetic field to the slot. An orientation portion to be applied; and A primary sprue disposed between a lot opening and a nozzle of the injection molding machine and serving as a flow path for guiding the fluid mixture supplied from the nozzle from the upstream side to the downstream side along the axial direction; A runner that is a flow path that branches laterally from the downstream side of the primary sprue and distributes the fluid mixture to the slots; and the slot that is in the orientation portion along the axial direction from the downstream side of the runner. A flow passage portion having a secondary sprue that is a flow passage filling the fluid mixture into the opening of the flow passage, and the flow passage portion has at least a first flow passage portion having the primary sprue and at least the secondary sprue. A second flow path portion, and the first flow path portion and the second flow path portion are separable and press-contacted to form the runner in cooperation.

(2) In the manufacturing apparatus of the present invention, unlike the prior art, not only the flow path portion but also the orientation portion is provided on the fixed side. This increases the degree of freedom in designing the flow channel (especially the second flow channel constituting the secondary sprue that reaches the slot of the rotor core) and shortens the flow channel (especially the secondary sprue that tends to be long). Becomes easy. In addition, when obtaining the same effect as the manufacturing apparatus of this invention using the manufacturing apparatus which provided the orientation part in the movable side as shown in FIG. 3, it has arrange | positioned at least in the center of the base part 710 provided in the fixed side. It is necessary to place the nesting 7110 at the position of the shielding plate 640 of the orientation mold provided on the movable side, and also to provide the nesting 7110 with a function of preventing leakage of the orientation magnetic field. In this case, since the rotor (core) cannot be taken in and out with the nest 7110 placed, a removal process of the nest 7110 and a mechanism therefor are required, leading to a significant reduction in productivity and complication of the manufacturing apparatus.

  By shortening the flow path, at least a fluid mixture (also simply referred to as “mixture”) composed of a binder resin (also simply referred to as “resin”) and anisotropic magnet particles (also simply referred to as “magnet particles”). In the secondary sprue, the amount of heat removal is reduced, and as a result, increase in viscosity and decrease in fluidity can be suppressed. As a result, even if the injection pressure (injection speed) is not increased too much, the mixture is sufficiently filled in the slots, and a rotor with less deformation and distortion can be obtained.

  In addition, since the mixture can be filled into the slot while maintaining a relatively low viscosity state, not only the increase in injection pressure is suppressed, but also the posture change of the magnet particles in the slot is facilitated, and the slot is filled. The degree of orientation of the bonded magnet can be increased.

<Others>

(1) The movable side and the fixed side of the injection molding machine referred to in this specification are opened after injection molding with reference to the boundary surface (gate surface) between the outlet of the secondary sprue and the inlet (open end) of the slot. In this case, the side that moves together with the molded product (the rotor filled with the bond magnet) is the movable side, and the opposite side is the fixed side. In addition, in order to remove the solidified product of the fluid mixture formed in the flow path from the injection nozzle to the opening of the slot, the second flow path portion is separated and moved by the dividing surface of the first flow path portion and the runner, The second flow path portion is included on the fixed side (mold).

(2) The rotor referred to in this specification may be an inner rotor or an outer rotor. In the case of the outer rotor, the form of the rotor core when the bonded magnet is injection-molded may be a form that can be easily attached to the manufacturing apparatus, and may be different from the final form of the outer rotor when assembled to the motor. Good.

  The form and number of the slots are selected according to the specifications of the rotor and the motor, and it is preferable that the plurality of slots be evenly arranged around the axis of the rotor core during injection molding. “Equally arranged” means that the pitch of slots arranged in the circumferential direction is equal.

(3) In this specification, the fixed side of the injection molding machine is appropriately referred to as one end side, and the movable side facing it is referred to as the other end side. The side closer to the rotation center of the rotor core is referred to as “inner circumference side”, and the side farther from the rotation center is referred to as “outer circumference side”. The “axial direction” is a direction along the central axis of the rotor core or the rotation axis when the injection molding is performed. Usually, this axial direction is the moving direction of the mold (movable side) constituting the manufacturing apparatus of the present invention, and the extending direction of the sprue connected to the injection nozzle. Similarly, “around the axis” is the circumferential direction around the central axis of the rotor core or its rotation axis when injection molding is performed. The “lateral direction” is a direction orthogonal to the axial direction unless otherwise specified, and is usually a direction along the dividing surface of the mold. Unless otherwise specified, the injection molding referred to in this specification includes transfer molding.

(4) Unless otherwise specified, “x to y” in this specification includes a lower limit value x and an upper limit value y. Any numerical value included in various numerical values or numerical ranges described in the present specification can be newly established as a range such as “ab” as a new lower limit value or upper limit value.

It is a perspective view which shows a rotor core and the solidified material which arises in the flow path which reaches the slot. It is sectional drawing which shows the state which closed the mold (clamping) the shaping die concerning a present Example. It is sectional drawing which shows the state which opened the molding die concerning a present Example. It is sectional drawing which shows the state which closed the mold which concerns on the reference example. It is sectional drawing which shows the state which opened the molding die concerning a reference example.

  One or more components arbitrarily selected from the matters described in the present specification may be added to the configuration of the present invention described above. Which embodiment is the best depends on the target, required performance, and the like. A component related to a manufacturing method can be a component related to an object as a product-by-process claim in a certain case.

《Fixed side mold》
The fixed mold according to the present invention includes a flow path portion and an orientation portion. A flow path part is comprised by the 1st flow path part and the 2nd flow path part which can be divided at least into two. The first flow path portion has a primary sprue, and the second flow path portion has a secondary sprue. The runner is formed by joining open grooves formed on each pressure contact end face side of the first flow path portion and the second flow path portion.

  The cross-sectional shape of each flow path does not matter, but if it is circular, the ratio (S / V) of the surface area (S) to the volume (V) of the flow path can be reduced, and the amount of heat removed from the flowing mixture and thus the temperature can be reduced. Can be suppressed.

  In the case of the present invention, it is preferable that the second flow path portion is disposed on one end side of the orientation portion and the orientation mold is configured in cooperation with the orientation portion. As a result, the second flow path portion can be disposed close to the orientation portion containing the rotor core, and the flow path length (particularly, the secondary sprue length) can be easily shortened. And the 1st flow path part isolate | separated from the 2nd flow path part comprises the flow path mold arrange | positioned separately from the orientation mold at the one end side of the orientation mold so that it can be divided | segmented. Is preferred.

  Specifically, for example, the flow channel mold preferably has a convex portion protruding near the center of the other end side, and the alignment mold preferably has a concave portion where the convex portion of the flow channel mold overlaps near the center of the one end side. It is. In addition, since at least the other end surface of the second flow path portion is in contact with or close to the opening-side end surface of the rotor core, it is preferable that the entirety or at least the vicinity of the contact surface is made of a nonmagnetic material. Thereby, the leakage to the 2nd flow-path part or flow-path metal mold | die of the orientation magnetic field applied to a rotor core is suppressed. In addition, the nonmagnetic material referred to in this specification means a material having a lower magnetic permeability or saturation magnetization than a ferromagnetic material constituting the rotor core or the yoke. Examples of such a nonmagnetic material include austenitic stainless steel.

  The flow path portion may be a type that does not heat the flow path (sprue or runner) (so-called cold runner) or a type that heats the flow path (so-called hot runner). However, in the case of the present invention, since the flow path can be shortened, even a cold runner type that can simplify the structure of the flow path part and thus the manufacturing apparatus can ensure a low viscosity or high fluidity of the mixture. Of course, the flow path is heated to ensure further low viscosity and high fluidity of the mixture, and to increase the orientation of the bond magnet or to reduce the distortion of the rotor by reducing the injection pressure (reducing filling pressure). You may plan.

  For example, the orientation portion is preferably composed of a housing portion that houses the rotor core, an orientation yoke disposed around the housing portion, and an orientation magnetic field source (particularly a permanent magnet) disposed around the orientation yoke. . In this case, as long as the accommodating portion is a cylinder that can accommodate the rotor core, the accommodating portion may be integrated with the orientation yoke or separate. Further, when a rare earth sintered magnet is used as the orientation magnetic field source, a strong orientation magnetic field can be applied to the slot of the rotor core while the orientation portion and thus the orientation mold are made compact. When the orientation magnetic field source is an electromagnetic coil, cooling or the like is required. However, when the orientation magnetic field source is a permanent magnet as in the present invention, cooling or the like is not necessary, and the orientation mold can be simplified. It becomes.

<Rotor core>
The rotor core is made of a soft magnetic material, and is usually made of a laminated body of electromagnetic steel sheets with insulation coating on both surfaces, a dust core obtained by press-molding insulation-coated metal particles (soft magnetic particles), or the like. The soft magnetic material may be any material, but is preferably an iron-based material such as pure iron, silicon steel, or alloy steel.

  As long as there are at least two slots arranged around the shaft hole provided in the center of the rotor core, the shape and the number thereof do not matter. Since the slot according to the present invention is filled with the bond magnet, the degree of freedom of the shape is high. For example, even in the radial type extending linearly from the center to the radial direction, the convex type having a convex shape on the inner peripheral side However, it may be a multilayer type having a plurality in the radial direction.

《Anisotropic bonded magnet》
The anisotropic bonded magnet that is filled in the slot of the rotor core is made of anisotropic magnet particles and a binder resin. The type of anisotropic magnet powder to be used is not limited. For example, high-performance rare earth anisotropic magnet powder such as Nd-Fe-B magnet powder, Sm-Fe-N magnet powder, Sm-Co magnet powder, etc. Is preferred. The anisotropic magnet powder is not limited to a single powder, and may be a mixed powder obtained by mixing a plurality of types of powders. The mixed powder is not limited to those having different component compositions, and 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 an anisotropic magnet powder, it is possible to increase the density of the magnet particles and thus improve the performance of the rotor and motor. The anisotropic bonded magnet according to the present invention may be a mixture of isotropic magnet particles, ferrite magnet particles, and the like as long as anisotropic magnet particles are present.

  As the binder resin, known materials including rubber can be used. Considering the fluidity and filling properties of the mixture, the binder resin is preferably a thermoplastic resin in the case of injection molding. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, acrylonitrile / styrene resin, acrylonitrile / butadiene / styrene resin, methacrylic resin, vinyl chloride, polyamide (PA), polyacetal, polyethylene terephthalate, ultrahigh molecular weight polyethylene, polybutylene terephthalate. Methylpentene, polycarbonate, polyphenylene sulfide (PPS), polyetheretherketone, liquid crystal polymer, polytetrafluoroethylene, polyetherimide, polyarylate, polysulfone, polyethersulfone, polyamideimide and the like.

  The fluid mixture according to the present invention is prepared by, for example, heating raw material pellets made of magnet particles and resin introduced from a hopper with a heater provided in an injection cylinder or the like. The heating temperature at this time is usually adjusted within a temperature range equal to or higher than the melting point of the resin. If the flow path mold according to the present invention is used, the binder resin is not limited to a resin having a low melting point or crystallization temperature (for example, PA), but also to a resin having a high melting point or crystallization temperature (for example, PPS). A highly accurate (low distortion) rotor having a bond magnet with a high degree of orientation can be obtained. A resin having a high melting point is suitable as a binder resin because it has excellent heat resistance and durability. As these resins, for example, a resin having a melting point of 280 ° C. or higher, further 300 ° C. or higher can be used as the binder resin. Note that the crystallization temperature is lower than the melting point, but can be changed depending on the cooling rate or the like. Therefore, the melting point is used here as one index for classifying the resin. However, the binder resin according to the present invention may be crystalline or amorphous regardless of its crystallinity.

  When the anisotropic bonded magnet is formed by transfer molding, a thermosetting resin may be used as the binder resin. As the thermosetting resin, for example, epoxy resin, unsaturated polyester resin, amino resin, phenol resin, polyamide resin, polyimide resin, polyamideimide resin, urea resin, melamine resin, urea resin, diallyl phthalate resin, polyurethane, etc. are used. Can do.

《Use of internal magnet type motor》
Unless otherwise specified, the motor according to the present invention includes a generator in addition to the electric motor, and can be called a rotating machine. In addition, in the internal magnet type motor referred to in this specification, 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, 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 Hall element, a rotary encoder, or a resolver is also included. 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 motor provided with the rotor according to the present invention may be used for any purpose. For example, a motor for driving a vehicle used in an electric vehicle, a hybrid vehicle, a railway vehicle, etc., an electric appliance used in an air conditioner, a refrigerator, a washing machine, or the like. Suitable for motors and the like.

  The present invention will be described more specifically with reference to examples. In this embodiment, an inner rotor manufacturing apparatus used for an IPM motor will be described. Note that the vertical direction described below is the vertical direction in the figure unless otherwise specified, regardless of the actual arrangement, movable direction, and the like.

《Inner rotor》
As shown in FIG. 1, the rotor core 1 serving as the skeleton of the inner rotor is formed by laminating silicon steel plates punched into a desired shape. More specifically, the rotor core 1 has a substantially cylindrical shape, and has a shaft hole 11 provided in the center and six substantially U-shaped through-holes 121 arranged evenly around the central axis. To 126 (collectively referred to as “slot 12”). Each silicon steel plate from which the shaft hole 11 and the slot 12 are punched is fixed by rivets or caulking.

  A rare earth anisotropic bonded magnet (simply referred to as “bonded magnet”) is injection-molded in each slot 12 of the rotor core 1 in an orientation magnetic field, whereby an inner rotor is obtained. FIG. 1 also shows the solidified product 2 of the fluid mixture formed in the flow path from the injection nozzle to the inlet (opening) of each slot 12 when performing the injection molding.

  The solidified product 2 reflects a flow path when the fluid mixture is filled into each slot 12, and includes one short sprue portion 21 (primary sprue portion) extending in the axial direction and the sprue portion 21. 6 runner parts 221 to 226 (which are collectively referred to as “runner part 22”) extending laterally from the slot 12 toward the center of the opening, and each slot 12 from the downstream side of each runner part 22. It consists of six short secondary sprue portions 231 to 236 (each collectively referred to as “secondary sprue portion 23”) extending in the axial direction to each of the openings. More specifically, the sprue portion 21 has a conical shape that gradually increases in diameter from the upstream side toward the downstream side. The runner portion 22 has a substantially cylindrical shape that is smoothly connected from the downstream side of the sprue portion 21. The secondary sprue portion 23 has a conical shape that gradually decreases in diameter from the upstream side toward the downstream side, and in particular, the opening end side (opening end side of the slot 12) has a sharpened shape. Yes.

<Molding mold>
(1) Outline FIG. 2A and FIG. 2B (hereinafter referred to as “FIG. 2” together) show a molding die D used for injection molding a rare earth anisotropic bonded magnet into the slot 12 of the rotor core 1. . FIG. 2A shows a state where the mold is closed, and FIG. 2B shows a state where the mold is opened.

  The molding die D is used by being set in a general-purpose vertical or horizontal injection molding machine. Such an injection molding machine usually measures a raw material supplied from a hopper and a hopper for feeding pellets produced by kneading a binder resin and rare earth anisotropic magnet powder (particles), which are raw materials for a bond magnet. Screw to transport, Cylinder to store screw, Heater to heat and melt raw material in cylinder, Injection nozzle attached to tip of cylinder and connected to injection port of molding die D, Applying back pressure to screw and moving forward And an actuator that ejects the melted raw material (fluid mixture) from the injection nozzle. Further, a mold clamping mechanism (hydraulic actuator or the like) for opening and closing the molding die D, a protruding mechanism for taking out the inner rotor after injection molding, and the like are also provided. In addition, although the manufacturing apparatus of this invention may be grasped | ascertained as the injection molding machine which set the molding die, it can also grasp | ascertain as a molding die single-piece | unit. Below, the molding die D important for this invention is explained in full detail.

(2) Molding Mold The molding mold D is a so-called three-plate mold as shown in FIG. 2, and specifically, a three-layer structure of a base mold 5, an orientation mold 6 and an injection mold 7. Consists of. The base mold 5 is a movable mold attached to the movable side of the injection molding machine, and the orientation mold 6 and the injection mold 7 are fixed molds attached to the fixed side of the injection molding machine.

  The base mold 5 includes a base portion 51, a protruding distance securing portion 52 disposed on the base portion 51, and a protruding portion 53 accommodated in the center of the protruding distance securing portion 52 so as to advance and retreat. One side (upper side in FIG. 2) of the protrusion 53 is formed in a cylindrical shape having substantially the same outer diameter as that of the rotor core 1, and is inserted into the shaft hole 11 of the rotor core 1 at the tip (upper end side in FIG. 2). A shaft portion 531 is formed so as to protrude.

  When the shaft hole 11 of the rotor core 1 is fitted into the shaft portion 531, the other end surface (lower end surface) of the rotor core 1 comes into contact with a stepped surface on the tip side of the protruding portion 53. In this way, the rotor core 1 is held with high accuracy on the tip side of the protrusion 53. The protruding portion 53 is made of austenitic stainless steel (nonmagnetic material). Further, the forward and backward driving of the protrusion 53 is performed by a protrusion mechanism (actuator or the like) of an injection molding machine (not shown). When the rotor core 1 set in the movable base mold 5 is inserted into the fixed orientation mold 6, the rotor core 1 may move due to the magnetic attractive force of the orientation mold 6. For example, a pin may be provided at the tip of the shaft portion 531 to prevent the movement.

  The orientation mold 6 is sandwiched between the frame portion 62, shielding plates 63 and 64 that are inscribed in the frame portion 62 to form the upper and lower bottom surface portions of the frame portion 62, and inscribed in the annular portion 62. And the annular orientation magnetic field body 66 (orientation portion) accommodated by the shielding plates 63 and 64 and the shielding ring 65. The shielding plates 63 and 64 and the shielding ring 65 are made of austenitic stainless steel (nonmagnetic material).

The orientation magnetic field body 66 has six orientation yokes (not shown) projecting radially and outwardly on the outer peripheral side corresponding to the slots 12 of the rotor core 1 and bridges the orientation yokes in a circular arc shape, and smoothly continues in the center. 12 permanent magnets (not shown) that serve as orientation magnetic field sources arranged with the same poles facing the opposite side surfaces in the circumferential direction of the orientation yokes. ).
An electromagnet may be used as the orientation magnetic field source. However, by using a permanent magnet made of a rare earth sintered magnet or the like, it is possible to reduce the size and simplification of the orientation magnetic field body 66 and the molding die D. Thereby, the injection molding of the bond magnet becomes possible by combining the molding die D according to the present embodiment with various general-purpose injection molding machines.

  A concave portion 641 is formed on the central upper end surface side of the shielding plate 64, and a secondary flow passage body 67 (second flow passage portion) is press-fitted and fixed on the central lower end surface side. The secondary flow path body 67 has a convex shape that is fitted into the accommodating portion 667 of the orientation magnetic field body 66 in which the rotor core 1 is accommodated. Six secondary sprue parts 673 corresponding to the secondary sprue part 23 are formed inside the secondary flow path body 67. On the upper end side of the secondary flow path body 67, a runner portion 672 that is continuous with each secondary sprue portion 673 is formed. The runner part 672 has a semicircular groove shape corresponding to the lower half of the runner part 22. Note that the upper end surface of the secondary flow path body 67 is flush with the bottom surface of the recess 641. The secondary flow path body 67 is also made of austenitic stainless steel (nonmagnetic material).

  The injection mold 7 includes a base portion 71, a mounting portion 72 attached to the fixed side of the injection molding machine, a locating ring 74 that centers the injection nozzle and the mold, and leakage of the fluid mixture in contact with the injection nozzle. The nozzle touch part 7311 which suppresses is provided. In addition, the center upper end side of the base part 71 is concave, and the center lower end side of the mounting part 72 is convex, and both overlap when the mold D is clamped.

  The base portion 71 has a convex portion 711 that protrudes downward and overlaps the concave portion 641 of the shielding plate 64. On the lower end surface side of the convex portion 711, six semicircular groove-like runner portions 712 corresponding to the upper half on the outer peripheral side of the runner portion 22 are formed. The base portion 71 is also made of austenitic stainless steel (nonmagnetic material).

  A primary flow path body 73 is press-fitted and fixed at the center of the mounting portion 72. A primary sprue portion 731 corresponding to the primary sprue portion 21 and six runner portions 732 branched in the lateral direction from the lower end side of the primary sprue portion 731 are formed inside the primary flow path body 73. The runner part 732 has a semicircular groove shape corresponding to the upper half on the center side of the runner part 22. When the molding die D is clamped, the runner part 732 cooperates with the runner part 712 and the runner part 672 to configure a circular flow path (runner) corresponding to the runner part 22. The primary flow path body 73 is also made of austenitic stainless steel (nonmagnetic material).

  It may be considered that the primary flow path body 73 corresponds to the first flow path portion referred to in the present invention, and in addition to that, the one including the base portion 71 having the runner portion 712 may correspond to the first flow path portion. . Further, it may be considered that the base portion 71 and the primary flow path body 73 correspond to the flow path mold referred to in the present invention, and in addition to them, the one including the mounting portion 72 is the flow path mold according to the present invention. You may think that it corresponds.

  When the mold is closed and injection-molded as shown in FIG. 2A, the fluid mixture that becomes a bonded magnet is transferred from the injection nozzle (not shown) to the primary sprue portion 731 via the nozzle touch portion 7311 connected to the nozzle. The center of the upper end side of each slot 12 of the rotor core 1 passes through the runner portion 732 (further, the runner portion 712), the runner portion 672, and the secondary sprue portion 673 (also collectively referred to as “flow passage portion”). Is filled into the opening.

  After the injection molding, as shown in FIG. 2B, the mold is opened and the base mold 5 is retracted to obtain an IPM rotor inner rotor in which the slot 12 is filled with an anisotropic bonded magnet. The solidified product 2 generated in the flow path portion is collected and reused after being subjected to a pulverization process or the like.

1 Rotor core 12 Slot 5 Base mold (movable mold)
6 Oriented mold (fixed side mold)
67 Secondary channel body (second channel part)
7 Injection mold (fixed side mold)
73 Primary channel body (first channel part)

Claims (4)

A slot, which is a cavity that is provided around the rotor core axis and has an opening on at least one end, is filled with a fluid mixture that is a mixture of binder resin and anisotropic magnet particles that are heated and fluidized, and An apparatus for manufacturing an internal magnet type rotor used for obtaining an internal magnet type rotor having a magnetic pole made of an anisotropic bonded magnet obtained by solidifying a fluid mixture,
A movable mold disposed on the movable side of the injection molding machine and capable of supporting the other end of the rotor core;
A fixed mold disposed on the fixed side of the injection molding machine opposite the movable mold,
The fixed mold is
An orientation unit that accommodates the rotor core inserted from the other end side and applies an orientation magnetic field to the slot;
A primary sprue disposed between the opening of the slot and the nozzle of the injection molding machine and serving as a flow path for guiding the fluid mixture supplied from the nozzle from the upstream side to the downstream side along the axial direction; A runner that is a flow path that branches laterally from the downstream side of the primary sprue and distributes the fluid mixture to the slots, and the runner that is in the orientation section along the axial direction from the downstream side of the runner. A channel portion having a secondary sprue that is a channel for filling the fluid mixture into the opening of the slot,
The flow path portion includes at least a first flow path portion having the primary sprue and at least a second flow path portion having the secondary sprue,
The first flow passage portion and the second flow passage portion are separable and press-contacted to form the runner in cooperation with each other.   2. The internal magnet-type rotor according to claim 1, wherein the second flow path portion is made of a nonmagnetic material and disposed on one end side of the orientation portion, and forms an orientation mold in cooperation with the orientation portion. manufacturing device.   The said 1st flow-path part is a manufacturing apparatus of the internal magnet type | mold rotor of Claim 2 which comprises the flow path metal mold | die arrange | positioned by the one end side of the said orientation metal mold so that division | segmentation with this orientation metal mold | die is possible. The flow path mold has a convex portion protruding near the center of the other end side,
The said orientation metal mold | die is a manufacturing apparatus of the internal magnet type | mold rotor of Claim 3 which has a recessed part by which this convex part is inserted by the one end side center vicinity.

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