JP7176210B2 - Rotor manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an injection molding machine used for molding bonded magnets to manufacture rotors (rotors for electric motors) and the like.

There are various types of electric motors (simply referred to as "motors" including generators). Recently, with the development of inverter control and the spread of high-performance rare-earth magnets, power-saving and highly efficient synchronous machines are frequently used. A synchronous motor is equipped with permanent magnets in the rotor and armature windings (coils) in the stator. It is an AC motor that generates a rotating magnetic field and drives a rotor.

Synchronous machines include a surface permanent magnet synchronous motor (simply referred to as an "SPM motor") in which permanent magnets are arranged on the surface of a rotor, and a surface permanent magnet synchronous motor (simply called an "SPM motor") in which permanent magnets are arranged on the surface of a rotor. There is an internal (embedded) magnet type motor (Interior Permanent Magnet Synchronous Motor, simply referred to as "IPM motor"). Conventionally, sintered magnets have been used as permanent magnets (magnetomotive sources), but bonded magnets, which have a high degree of freedom in shape and are excellent in productivity and yield, are now being used.

Bond magnets are formed by, for example, injection molding a rotor core in which electromagnetic steel sheets are laminated. At this time, the rotor core becomes part of the mold that defines the injection filling area (cavity). Then, a molten mixture of magnet powder and resin is injected and filled from one end face side of the rotor core which is in pressure contact with the dividing face of the mold (for example, fixed mold) on the injection unit side. Here, if the pressure contact force acting between one end surface of the rotor core and the parting surface of the mold is insufficient, the molten mixture leaks into the gap between the two surfaces, causing defects such as so-called burrs. Therefore, it is necessary to perform injection molding while applying a sufficient pressing force between both surfaces.

JP-A-5-169497

By the way, when a conventional injection molding machine is used, the pressure contact force is applied as a mold clamping force by a mold clamping unit. Mold clamping units are roughly classified into direct pressure type and toggle type. In the direct pressure type, the clamping force is generated by a hydraulic cylinder. Therefore, even if there is a dimensional error (variation) in the axial height (layer thickness) of the rotor core, the pressing force is maintained substantially constant by adjusting the hydraulic pressure to the hydraulic cylinder, which is the drive source.

However, the toggle type, which is currently the mainstream, generates a mold clamping force by moving a mechanical link by a predetermined amount. Therefore, the dimensional error of the rotor core has a great effect on the pressure contact force. For example, even if the lamination thickness of the rotor core changes by only about 0.2 to 0.3 mm, the pressure contact force changes by several tons. Moreover, as the number of layers of the magnetic steel sheets increases, the amount of variation in the thickness of the layers also increases. Or it tends to be excessive. If the contact pressure is too small, burrs will be generated, and if the contact pressure is too large, the mold and the mold clamping unit may be damaged or their life may be shortened.

Note that Patent Document 1 proposes an injection molding apparatus that eliminates the gap that causes burrs, but does not use a laminated body of electromagnetic steel sheets, such as a rotor core, as a work.

The present invention has been devised in view of the above circumstances. It is an object of the present invention to provide an injection molding machine capable of

As a result of intensive research to solve this problem, the inventors of the present invention have found that even if the mold clamping unit is a toggle type, while absorbing variations in the thickness of the laminated body, there is a gap between one end surface of the laminated body and the dividing surface of the mold. We conceived of a new mechanism that can make the pressure contact force acting on the surface almost constant. By embodying and developing this, the present invention described below has been completed.

"Injection molding machine"
(1) The present invention comprises a fixed mold, a movable mold, a toggle-type mold clamping unit for advancing and retracting the movable mold with respect to the fixed mold, and a molten mixture in which magnet particles are mixed in the molten resin. and an injection unit for injecting from the mold side, a laminate formed by laminating electromagnetic steel sheets is inserted into the cavity of the movable mold, and pressed against the dividing surface of the fixed mold from one end surface side of the laminate. An injection molding machine that molds a bond magnet by injecting the molten mixture into the side surface portion or the hollow portion of the laminate, wherein the mold clamping unit is operated to bring the fixed mold and the movable mold close to or in contact with each other. The injection molding machine further comprises a pressure contact force adjusting unit that adjusts the pressure contact force of the one end surface of the laminate to the dividing surface of the fixed mold within a predetermined range when the laminate is closed.

(2) According to the injection molding machine of the present invention, while using an energy-saving and highly responsive toggle-type mold clamping unit, the press contact force adjusting unit controls one end face of the laminate and the fixed mold (injection unit side) when the mold is closed. It is possible to stably maintain the pressure contact force acting between the parting surface of the mold) within a predetermined range. Therefore, even when a bonded magnet is formed by injecting a molten mixture into a laminated body in which a large number of electromagnetic steel sheets are laminated and the dimensional error in the axial direction (variation in lamination thickness) tends to increase, burrs and gold are generated. It is possible to suppress the damage and shortening of the life of the mold and the mold clamping unit.

《Pressure adjustment unit/Injection molding method》
The present invention may be grasped as a pressure contact force adjusting unit that constitutes a part of the injection molding machine described above. The present invention can also be understood as an injection molding method using the above-described injection molding machine or a rotor manufacturing method.

Incidentally, the time at which one end surface of the laminate and the dividing surface of the fixed mold abut (pressure contact) precedes the time at which the fixed mold and the movable mold close (mold clamping) (for example, the completion time). may be followed or almost simultaneously. When a toggle type mold clamping unit is used, the divided surfaces (mold opening surfaces) of the fixed mold and the movable mold are normally in contact (abutting) with each other when the mold is closed due to the mold thickness adjustment performed in advance. However, in the case of the present invention, as long as a sufficient pressure contact force is ensured between one end surface of the laminate and the dividing surface of the fixed mold, the dividing surfaces of the fixed mold and the movable mold are not necessarily in contact with each other when the mold is closed. (that is, it may be in the proximity state immediately before contact).

"others"
(1) In this specification, the fixed side of the injection molding machine is referred to as "one end", and the opposite movable side is referred to as "other end". The direction of the axis of the laminate is called "axial direction". The direction in which the magnetic steel sheets are sequentially laminated is called the "laminating direction". The axial direction and the stacking direction are usually the same. As appropriate, the axial direction is also referred to as the "longitudinal direction", and the direction orthogonal thereto is referred to as the "lateral direction". The lateral direction is generally the direction in which one end surface of the laminate extends and the dividing surface between the fixed type and the movable type. Further, the side closer to the axis of the laminate is called the "inner side", and the side farther from the axis is called the "outer side".

(2) Injection molding as used herein also includes transfer molding. The molten mixture flow path (sprue or runner) formed in the stationary mold may be of the unheated type (so-called cold runner) or the heated type (so-called hot runner).

(3) The rotor (core) referred to in this specification may be an outer rotor (core) or an inner rotor (core). The motor in which each rotor is used may be an SPM motor or an IPM motor. Further, the rotor according to the present invention may be used not only in motors but also in generators. In this specification, for the sake of convenience, the term "motor" is simply used to include generators.

(4) Unless otherwise specified, "x to y" as used herein includes the lower limit value x and the upper limit value y. Any numerical value included in any numerical value or numerical range described herein may be used as a new lower or upper limit to establish a new range such as "a to b."

1 is a front cross-sectional view schematically showing an injection molding machine that is an embodiment; FIG. It is an enlarged view showing the movable mold and the pressure contact force adjusting unit when the hydraulic cylinder of the injection molding machine is slightly moved. It is an AA sectional view of the enlarged view. FIG. 4 is a hydraulic circuit diagram necessary for operating a hydraulic cylinder that constitutes the pressure contact force adjusting unit. FIG. 4 is a front cross-sectional view schematically showing a state during mold thickness adjustment; FIG. 4 is a front cross-sectional view schematically showing how the rotor core is set. FIG. 4 is a front cross-sectional view schematically showing a state when hydraulic pressure is applied to a hydraulic cylinder of the pressure contact force adjusting unit; FIG. 4 is a front cross-sectional view schematically showing how the mold is closed. FIG. 4 is a front cross-sectional view schematically showing a state during injection molding; FIG. 4 is a front cross-sectional view schematically showing how the mold is opened. FIG. 4 is a front cross-sectional view schematically showing a state at the time of sticking out;

One or more components arbitrarily selected from the items described herein can be added to the configuration of the present invention described above. The contents described in this specification appropriately apply not only to the injection molding machine but also to each unit constituting the machine, the injection molding method, and the like. Also, even if it is a method component, it can also be a component related to an object. Which embodiment is the best depends on the target, required performance, and the like.

《Pressure adjustment unit》
Various forms are conceivable for the pressure contact force adjusting unit. For example, the pressing force adjustment unit is composed of a hydraulic cylinder that generates a pressing force between one end surface of the laminate and the dividing surface of the stationary mold, and a hydraulic adjustment unit that adjusts the hydraulic pressure acting on the hydraulic cylinder. In this case, a substantially constant and sufficiently large pressing force is ensured.

When sufficient daylight can be secured, the hydraulic cylinder and the movable mold cavity part (cavity mold) may be arranged in series in the vertical direction. For example, a hydraulic cylinder may be arranged between the movable platen and the cavity of the movable mold.

When sufficient daylight cannot be ensured, the hydraulic cylinders may be arranged in parallel in the horizontal direction of the cavity of the movable mold. In this case, the pressing force of the hydraulic cylinder is transmitted to the cavity portion of the movable mold via one or more transmission members (connecting members).

The daylight is the maximum distance between the movable platen and the fixed platen (fixed platen) when the mold clamping unit is operated to retract the movable platen (to move to the other end side).

The hydraulic adjustment unit includes a hydraulic circuit that supplies hydraulic oil from a hydraulic source such as an oil pump to the hydraulic cylinder and adjusts the hydraulic pressure acting on the hydraulic cylinder within a set value. The hydraulic circuit includes, for example, a pressure regulating valve (reducing valve) that keeps the hydraulic pressure acting on the hydraulic cylinder within a predetermined value, a pressure reducing valve (relief valve) that reduces excessive hydraulic pressure acting on the hydraulic cylinder when the mold is closed, etc. It is composed of a check valve that prevents the excessive hydraulic pressure from acting on the hydraulic source, and an oil passage (piping) that connects each valve to the hydraulic source. The hydraulic source and hydraulic circuit (part) may be configured exclusively for the hydraulic pressure adjusting unit, or may be configured for shared use with other units.

《Fixed type and movable type》
The fixed mold and the movable mold are each composed of a single mold or a plurality of molds arranged on a fixed platen and a movable platen of the injection molding machine. The stationary mold includes at least a nozzle port that contacts the injection nozzle, and a channel (parts that become sprues, runners, gates, etc.) through which the injected molten mixture flows. Depending on the channel configuration, the stationary mold usually consists of a combination of multiple molds that are separable to remove residue (sprue, etc.).

The movable mold is, for example, a spacer block attached to the movable side mounting plate, a movable side receiving plate, a movable side mold plate, and a cavity type (movable mold) that is accommodated at one end side of the movable side mold plate and into which the laminate is inserted. (cavity portion), etc. The movable mold is usually provided with an ejector mechanism for ejecting the cavity mold in order to eject the rotor after injection molding. The ejector mechanism includes, for example, an ejector rod that advances and retracts hydraulically or electrically, an ejector plate that is pressed by the ejector rod, and guide pins that connect the ejector plate and the cavity mold.

When the hydraulic cylinders are arranged in parallel as described above, the ejector plate and the guide pin also serve as part of the transmission member for transmitting the pressing force of the hydraulic cylinders to the cavity mold (and thus to one end face of the laminate). can be

《Laminate》
The laminate consists of a laminate of electromagnetic steel sheets. An electromagnetic steel sheet is generally a soft magnetic steel sheet coated with resin or ceramics on both sides for insulation. A large number of laminated electromagnetic steel sheets are fixed by caulking, welding, or the like. The laminated bodies are, for example, rotor cores and stator cores that form housings (yokes) of rotors and stators. A rotor core will be described below as an example of a laminate.

In the case of SPM motors, bond magnets are formed on the surface of the rotor core. Bond magnets are formed on the inner peripheral side of the outer rotor core, and bond magnets are formed on the outer peripheral side of the inner rotor core. In either case, the bond magnet formed on the surface side may be divided into individual magnetic poles or may be continuous like a ring. In the case of an IPM motor, bond magnets are formed in single-layer or multi-layer hollow portions (slots) provided in the rotor core for each magnetic pole.

《Bond Magnet》
The bonded magnet may be an anisotropic bonded magnet composed of anisotropic magnet particles and a (binder) resin, or an isotropic bonded magnet composed of isotropic magnet particles and a binder resin. Various types of magnet particles can be used. It is preferable that at least rare earth magnet particles having excellent magnetic properties are contained in the bonded magnet. Rare earth magnet particles include, for example, Nd--Fe--B system magnet particles, Sm--Fe--N system magnet particles, Sm--Co system magnet particles, and the like. Furthermore, the magnet particles are not limited to a single type, and may be a mixture of multiple types.

Known materials including rubber can be used for the resin. Considering the fluidity and fillability of the molten mixture, it is preferable to use a thermoplastic resin (for example, polyamide (PA), polyphenylene sulfide (PPS), etc.). In the case of transfer molding, a thermosetting resin (for example, epoxy, unsaturated polyester, etc.) may be used.

Incidentally, the anisotropic bonded magnet exhibits high magnetic properties by injection molding in an oriented magnetic field. An electromagnet can be used to apply an aligning magnetic field, but using an aligning mold composed of a permanent magnet (magnetic field source) such as a rare earth magnet and an aligning yoke will save energy and reduce the size of the injection molding machine (mold). It is preferable because it can be simplified or simplified. The shape and arrangement of the orientation mold vary depending on the desired rotor specifications, but it is usually arranged on the side of the movable mold.

In this embodiment, a rare-earth anisotropic bonded magnet is injection-molded on the inner peripheral side surface (surface portion) of an annular outer rotor core R (simply referred to as "core R") made of a laminate of electromagnetic steel sheets. Taking the injection molding machine S, the present invention will be described more specifically.

"Constitution"
FIG. 1A is an outline schematic diagram of the injection molding machine S, FIG. 1B is an enlarged view of the movable mold 2 and the pressure contact unit 3 (pressure contact force adjusting unit), which are the main parts of the injection molding machine S, and the AA sectional view in FIG. 1B is shown. 1C, and FIG. 1D shows a hydraulic circuit 4 (hydraulic adjustment unit) necessary for the operation of the pressing unit 3 . For convenience of explanation, the vertical direction, the horizontal direction, one end side and the other end side are set as shown in FIG. 1A. Also, FIG. 1B intentionally shows a state in which rods 3111 and 3121 of a hydraulic cylinder 31, a crank 32, etc., which will be described later, are slightly displaced to one end side with respect to the state of FIG. 1A (hydraulic OFF state).

The injection molding machine S includes a fixed mold 1 , a movable mold 2 , a press unit 3 , a hydraulic circuit 4 , a toggle type clamping unit 5 , an injection unit 6 and a frame 7 . The frame 7 includes a stationary platen 71 , a movable platen 72 , a rear platen 73 , and tie bars 74 that connect the stationary platen 71 and the rear platen 73 and serve as a sliding track for the movable platen 72 .

The fixed mold 1 consists of a mounting plate 11 fixed to a fixed platen 71 and having a nozzle port 111 to which a nozzle tip (not shown) of the injection unit 6 is connected, and a main sprue and a runner fixed to the mounting plate 11. It comprises a scraper plate 12 forming a flow path 121 and a mold plate 13 separably laminated on the wiper plate 12 to form a flow path 131 comprising runners, sub-sprues and gates. The dividing surface 132 on the other end side of the mold plate 13 serves as a mold opening surface and a surface to which one end surface r1 of the core R is pressed.

The movable mold 2 includes a mounting plate 24 fixed to the movable platen 72, spacer blocks 231 and 232 fixed to one end side of the mounting plate 24 (together simply referred to as "spacer block 23"), and spacer blocks. 23, a mold plate 21 fixed to one end of the mold plate 22, a cavity guide 25 fitted in the center of one end of the mold plate 21, and the cavity guide 25 A cavity mold 26 which can advance and retreat (slid) in the vertical direction and into which the core R is inserted, and an orientation mold 27 which consists of a rare earth sintered magnet (permanent magnet) and an orientation yoke and can apply an orientation magnetic field from the inner peripheral side of the core R. and

A concave portion 221 having a depth (d) in which the other end of the cavity mold 26 can be accommodated is formed on one end of the receiving plate 22 . When the other end surface 262 of the cavity mold 26 is in contact with the recess 221 , the one end surface 261 of the cavity mold 26 also contacts the dividing surface 211 (mold opening surface) of the mold plate 21 and the dividing surface 251 of the cavity guide 25 . It is in a state of being recessed toward the other end by the depth (d). In this embodiment, the maximum value of the clearance c1 and the like, which will be described later, is equal to the depth (d).

The pressing unit 3 includes hydraulic cylinders 311 and 312 (together simply referred to as "hydraulic cylinder 31"), a base plate 33 arranged on one end side of the mounting plate 24, and cranks 321 and 322 (together simply referred to as "hydraulic cylinder 31"). called “crank 32”), ejector plates 341 and 342 arranged on one end side of base plate 33 (both are simply called “ejector plate 34”), and ejector plate 342 is connected to the other end side and one end side is Guide pins 351 and 352 (together, simply referred to as "guide pins 35") connected to the cavity mold 26 are provided.

The crank 32 has its inner peripheral side fixed to the side surface of the base plate 33 and its outer peripheral side fixed to the rods 3111 and 3121 of the hydraulic cylinder 31 . As a result, the pressing force of the hydraulic cylinder 31 is transmitted to the base plate 33 via the crank 32, and the base plate 33 moves to one end side with respect to the mounting plate 24. As shown in FIG. However, a stopper 36 fixed to the mounting plate 24 restricts the amount of movement within a predetermined range (d or less in this embodiment).

The hydraulic circuit 4 includes an oil pan 41 in which hydraulic oil is stored, an oil pump 42 which draws up the hydraulic oil from the oil pan 41, pressurizes it, and supplies it to an oil passage 481, and maintains the hydraulic pressure in the oil passage 481 at a predetermined value. A pressure regulating valve 43 that regulates pressure, a check valve 45 that prevents excessive hydraulic pressure from acting on the oil pump 42, a flow rate regulating valve 46 that regulates the flow rate of hydraulic oil flowing through an oil passage 482 leading to the hydraulic cylinder 31, and a relief valve 47 for returning hydraulic oil to the oil pan 41 through an oil passage 483 when the hydraulic pressure in the hydraulic cylinder 31 becomes excessive. The hydraulic circuit 4 supplies hydraulic oil to the hydraulic cylinder 31 and maintains the hydraulic pressure within a predetermined range.

The mold clamping unit 5 includes a toggle link 51, a ball screw 52 that advances and retracts in the vertical direction to extend and retract the toggle link 51, a fulcrum 53 that connects the toggle link 51 to each part (●/fixed end in the figure) and a fulcrum. 54 (○/free end in the figure). The ball screw 52 is driven by an electric motor (not shown). The mold clamping unit 5 is also provided with an electric motor (not shown) that drives the ejector rod 58 that moves back and forth through the movable platen 72 .

Although not shown in detail, the injection unit 6 includes a hopper for containing pellets produced by kneading rare earth anisotropic magnet powder and thermoplastic resin, a heater for heating the pellets to form a molten mixture, A cylinder for pressure-feeding the molten mixture by a predetermined amount and a nozzle for injecting the molten mixture at high pressure are provided.

《Operation》
(1) Hydraulic pressure OFF
When hydraulic pressure is not applied to the hydraulic cylinder 31, the pressure unit 3 is in the state shown in FIG. 1A. In other words, the other end surface 262 of the cavity mold 26 and the concave portion 221 of the receiving plate 22 are in contact with each other, and the clearance c1 between them becomes zero. The base plate 33 is also in contact with the mounting plate 24, and the clearance c2 between the two is also zero. Conversely, the clearance c3 between the base plate 33 and the stopper 36 becomes a set value (for example, d).

(2) Mold thickness adjustment The mold thickness is adjusted as shown in FIG. That is, the toggle link 51 is extended to bring the dividing surface 132 on the fixed mold 1 side and the dividing surface 211 on the movable mold 2 side into contact with each other. Then, the fulcrum 53 of the toggle link 51 is set where a desired mold clamping force can be obtained. In this embodiment, the mold clamping force of the mold clamping unit 5: F1, the pressing force of the hydraulic cylinder 31: F2, and the minimum required space between the dividing surface 132 and the one end surface r1 to resist the injection pressure Pressure contact force: set so that Fmin<F2<F1, where Fmin.

Incidentally, the mold thickness is the sum of the lengths in the vertical direction (stroke direction) of the fixed mold 1 and the movable mold 2, and the distance (gap) between the fixed platen 71 and the movable platen 72 when the molds are closed. Equivalent to. 2 to 8, members that interlock with the hydraulic cylinder 31 are hatched.

(3) Core Set With no hydraulic pressure acting on the hydraulic cylinder 31, as shown in FIG. 3, the mold clamping unit 5 is operated to fold the toggle link 51 and open the mold. Then, the core R is set inside the cavity mold 26 .

(4) Oil pressure ON
When hydraulic pressure is applied from the hydraulic circuit 4 to the hydraulic cylinder 31, the state shown in FIG. 4 is obtained. That is, the pressing force of the hydraulic cylinder 31 is transmitted to the crank 32 , base plate 33 , ejector plate 34 , guide pin 35 and cavity mold 26 . As a result, the base plate 33 moves toward one end by a set value (for example, d) and contacts the stopper 36, and the clearance c3 between the stopper 36 and the base plate 33 becomes zero. That is, the base plate 33 cannot move further to the one end side. Due to this movement of the base plate 33 , the one end surface 261 of the cavity mold 26 also moves by a set value (for example, d) to the one end side, and becomes flush with the dividing surface 211 of the mold plate 21 and the dividing surface 251 of the cavity guide 25 . Also, the cavity mold 26 is in a state where the clearance c1 is lifted from the recess 221 by a set value (eg, d), and the base plate 33 is in a state where the clearance c2 is lifted from the mounting plate 24 by a set value (eg, d). .

At this time, the thickness of the mold plate 21 is adjusted so that the one end surface r1 of the core R slightly protrudes toward one end side from the one end surface 261 of the cavity mold 26, the dividing surface 251 of the cavity guide 25, and the dividing surface 211 of the mold plate 21. The depth and the like of the cavity mold 26 are set. In this embodiment, the projection amount (t) of the one end surface r1 with respect to the dividing surface 211 (dividing surface 251) is set to be approximately half (approximately d/2) of the clearances c1 and c2.

(5) Mold Closing With the state shown in FIG. 4 (the state in which hydraulic pressure is applied to the hydraulic cylinder 31), the mold clamping unit 5 is operated to extend the toggle link 51 to close the mold. At this time, as shown in FIG. 5, one end surface r1 of the core R abuts against the dividing surface 132 of the stationary mold 1. As shown in FIG. The pressing force acting between the two surfaces is generated by the pressing force of the hydraulic cylinder 31, and after the two surfaces are in contact with each other, the pressing force increases as the toggle link 51 expands.

However, the upper limit of the hydraulic pressure acting on the hydraulic cylinder 31 is regulated by the relief valve 47 of the hydraulic circuit 4 . Therefore, the upper limit value of the pressure contact force (F) acting between the dividing surface 132 and the one end surface r1 also becomes a predetermined value, and as described above, Fmin<F (≈F2)<F1. In this way, the dividing surface 132 and the one end surface r1 are stably pressed against each other with a substantially constant force.

The mold closing is completed when the movable mold 2 (movable platen 72) advances by the stroke set when the mold thickness is adjusted. At this time, since a predetermined mold clamping force (F 1 >F) is generated between the fixed mold 1 and the movable mold 2, the clearances c1, c2, and c3 are the same as those of the core R as shown in FIG. The value is substantially reduced by the protrusion amount (t) of the end surface r1.

(6) Molding After the mold is closed, the molten mixture is injected from the injection unit 6 as shown in FIG. The molten mixture is filled into the cylindrical cavity formed between the core R and the orienting mold 27 through the nozzle port 111 of the fixed mold 1 and the channels 121 and 131 . Thus, a ring-shaped bonded magnet is formed on the inner peripheral surface of the core R. As shown in FIG. The bond magnet is in a state in which the rare earth anisotropic magnet particles are oriented in a predetermined direction for each magnetic pole due to the application of an orientation magnetic field by the orientation mold 27 .

(7) Mold Opening After molding the bond magnet, the toggle link 51 is folded to open the mold as shown in FIG. At this time, the bond magnet (product portion) and the sprue and runner (residual portion) are separated at the gate portion.

(8) Eject
After the mold is opened, the ejector rod 58 is advanced to eject the cavity mold 26 as shown in FIG. Then, a core R (rotor) integrally formed with bond magnets is taken out from the cavity mold 26 . The outer rotor of the SPM motor was thus obtained.

In this embodiment, after the hydraulic pressure was once applied to the hydraulic cylinder 31, the next core R was injection-molded while maintaining this state (after the state shown in FIG. 4). In other words, the core setting (Fig. 3) -> mold closing (Fig. 5) -> molding (Fig. 6) -> mold opening (Fig. 7) -> ejection (Fig. 8) was repeated to sequentially manufacture the outer rotor.

(9) Supplement In the above-described embodiment, the mold is closed after the hydraulic cylinder 31 is operated, but the hydraulic cylinder 31 may be operated after the mold is closed or each time the mold is closed. In this case, it is possible to simplify the hydraulic circuit 4 without providing the check valve 45 or the relief valve 47 . However, if the hydraulic pressure is always applied to the hydraulic cylinder 31 as in the above-described embodiment, it becomes unnecessary to operate the hydraulic circuit 4 by detecting the completion of mold closing for each injection molding. Simplify control.

S injection molding machine 1 fixed mold 2 movable mold 26 cavity mold (cavity part)
3 pressure contact unit (pressure contact force adjustment unit)
31 hydraulic cylinder 4 hydraulic circuit (hydraulic adjustment unit)
5 Mold clamping unit

Claims (2)

A fixed mold, a movable mold, a toggle-type mold clamping unit that advances and retracts the movable mold with respect to the fixed mold, and an injection unit that injects a molten mixture containing magnet particles in molten resin from the fixed mold. When the mold clamping unit is operated and the fixed mold and the movable mold come close to each other or are brought into contact with each other, the pressing force exerted by one end surface of the laminated body formed by laminating the electromagnetic steel sheets on the divided surface of the fixed mold. Using an injection molding machine equipped with a pressure contact force adjustment unit that regulates the upper limit,
The laminate is inserted into the cavity of the movable mold, and the molten mixture is injected from one end surface of the laminate pressed against the dividing surface of the fixed mold into the side surface or hollow portion of the laminate for bonding. A manufacturing method for obtaining a rotor formed by molding a magnet,
A rotor manufacturing method in which the time at which the one end surface of the laminate and the dividing surface of the fixed mold abut against each other precedes the time at which the mold is closed. The pressing force adjustment unit includes a hydraulic cylinder that generates the pressing force;
a relief valve that regulates the upper limit of the hydraulic pressure acting on the hydraulic cylinder;
The method of manufacturing a rotor according to claim 1, comprising:

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