JP2022144812A - embedded magnet synchronous motor - Google Patents

Abstract

To provide an embedded magnet synchronous motor capable of raising an upper limit value of torque and enabling a rotor to be stacked in multiple stages.SOLUTION: In an embedded magnet synchronous motor having a rotor 10 with an embedded magnet, the rotor includes a rotating shaft 11 and a core unit CU attached to the rotating shaft, the core unit includes an annular inner core 20 attached to the rotating shaft with the inner peripheral end in contact with the outer peripheral end of the rotating shaft, a plurality of outer cores 30 arranged in the circumferential direction at positions spaced radially outward from the inner core and corresponding to respective magnetic poles, a plurality of magnets 40 arranged in the circumferential direction and arranged between outer cores adjacent to each other, and a resin mold portion 50 joined to the inner core and the outer core.SELECTED DRAWING: Figure 1

Description

The present invention relates to embedded magnet synchronous motors.

Patent Literature 1 discloses an embedded magnet synchronous motor having a rotor with magnets. The rotor includes a plurality of core piece portions and a plurality of permanent magnets that excite the core piece portions, and these members are fixed to each other by a molded resin portion. This motor has the advantage that magnetic flux leakage from the core piece is suppressed by the molded resin portion.

JP 2018-033307 A

In the motor disclosed in Patent Document 1, the rotor is coupled to the rotating shaft via the molded resin portion. Therefore, the upper limit of the torque is suppressed due to the strength of the molded resin portion and the adhesive strength between the molded resin portion and the rotating shaft. In addition, since it becomes difficult to fix a large number of core pieces at predetermined positions when insert-molding the rotating shaft, it is not possible to construct a structure in which the rotors are multi-layered in the axial direction.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an embedded magnet synchronous motor capable of increasing the upper limit of torque and allowing rotors to be stacked in multiple stages.

In order to solve the above problems, one aspect of the present invention is
An embedded magnet synchronous motor having a rotor with embedded magnets,
The rotor is
a rotating shaft;
a core unit attached to the rotating shaft;
with
The core unit is
an annular inner core attached to the rotating shaft with its inner peripheral end in contact with the outer peripheral end of the rotating shaft;
a plurality of outer cores arranged in the circumferential direction at positions spaced radially outward from the inner core and corresponding to respective magnetic poles;
a plurality of magnets disposed between the outer cores adjacent to each other and arranged in a circumferential direction;
a resin mold portion joined to the inner core and the outer core;
An embedded magnet synchronous motor is provided, comprising:

ADVANTAGE OF THE INVENTION According to this invention, while being able to raise the upper limit of a torque, the embedded magnet synchronous motor which made multistage stacking of a rotor possible is provided.

It is the figure which looked at the rotor of the embedded magnet synchronous motor of a present Example from the axial direction. It is the figure which looked at the inner core and the outer core from the axial direction. It is a figure which shows the process (press work) which shape|molds a resin mold part. It is a figure which shows the process (press work) which shape|molds a resin mold part. It is a figure which shows the process (press work) which shape|molds a resin mold part. FIG. 4 is a perspective view showing a case where core units are provided in multiple stages;

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

FIG. 1 is an axial view of the rotor of the embedded magnet synchronous motor of this embodiment, and FIG. 2 is an axial view of the inner core and the outer core. In the description below, the axial direction, the radial direction, the circumferential direction, the inner peripheral side, and the outer peripheral side are defined with reference to the axis of the rotating shaft of the rotor.

As shown in FIG. 1 , the rotor 10 includes a rotating shaft 11 made of a metal material and a core unit CU attached to the rotating shaft 11 . The core unit CU includes an annular inner core 20, a plurality of (10) outer cores 30 arranged in the circumferential direction on the outer peripheral side of the inner core 20 and corresponding to respective magnetic poles, and between the outer cores 30 adjacent to each other. and a resin mold portion 50 joined to the inner core 20 and the outer core 30 . The outer core 30 functions as a magnetic member that introduces the magnetic flux of the magnet 40 to the stator (not shown). Thus, the rotor 10 is configured as a spoke-type rotor in which the magnets 40 are arranged in the circumferential direction.

The inner core 20 and the outer core 30 are positioned and magnetically separated by a resin mold portion 50 interposed between the inner core 20 and the outer core 30 . Further, the resin molded portion 50 is formed on the outer peripheral side of the inner core 20 over the entire circumference of the core unit CU. Therefore, magnetic flux leakage from the outer core 30 to the inner core 20 and magnetic flux leakage from the outer core 30 to the rotating shaft 11 can be effectively suppressed.

The core unit CU is attached to the rotating shaft 11 by press-fitting the inner core 20 onto the rotating shaft 11 . That is, in the core unit CU, the inner core 20 is attached to the rotating shaft 11 with the inner peripheral end of the inner core 20 in contact with the outer peripheral end of the rotating shaft 11 . Therefore, the core unit CU is firmly fixed to the rotating shaft 11, and resistance to strong torque can be ensured.

In this embodiment, the number of magnetic poles is 10, but the number of poles is arbitrary.

The inner core 20 is configured, for example, by laminating a predetermined number of iron plates 20A (an example of a plate-like member) each having a shape shown in FIG. 2 in the axial direction. The inner core 20 can be configured using any metal material, and may use a non-magnetic material. For example, instead of the iron plate 20A, the inner core 20 may be configured by stacking metal plates made of a non-magnetic material. Since the material of the inner core 20 is not required to have magnetic properties similar to those of the outer core 30, there is no need to use an expensive electromagnetic steel sheet, and any metal material can be used.

On the other hand, the outer core 30 is configured, for example, by laminating a predetermined number of iron plates 30A each having the shape shown in FIG. 2 in the axial direction. The outer core 30 can be configured using a steel plate made of any material other than a cold-rolled steel plate. Further, the outer core 30 may be configured using a plate-shaped member (for example, an electromagnetic steel sheet) made of any magnetic material. A magnetic material that satisfies the magnetic properties required for the outer core 30 is appropriately used.

Thus, the inner core 20 and the outer core 30 do not have to be made of the same material. For this reason, while the outer core 30 is made of a magnetic material (metal material, such as an electromagnetic steel sheet) that satisfies the desired magnetic properties, the inner core 20 is made of another less expensive material (metal material, such as an inexpensive magnetic material). By using a steel plate, the cost of the motor can be reduced.

The magnets 40 are arranged at even angles around the rotating shaft 11 (shifted by 36°). The outer cores 30 are arranged at equal angles (shifted by 36°) around the rotating shaft 11 at positions sandwiched between the magnets 40 adjacent to each other.

The magnets 40 are rectangular parallelepipeds extending in the axial direction, and as shown in FIG. 1, the N poles or the S poles of the magnets 40 adjacent to each other are arranged in a direction facing each other. Thereby, each of the outer cores 30 functions as a magnetic pole that alternately repeats an N pole and an S pole in the circumferential direction.

As shown in FIG. 2, an iron plate 20A forming the inner core 20 is formed with engaging portions 21 around the rotating shaft 11 at even angles (with a deviation of 72°). The engaging portion 21 is formed in a concave or convex shape, and the mutually stacked iron plates 20A are engaged at the engaging portion 21, thereby contributing to positioning of the iron plates 20A in the circumferential direction and the radial direction.

Also, on the iron plate 20A, convex portions 22 and convex portions 23 arranged at equal angles (shifted by 72°) are provided alternately in the circumferential direction around the rotating shaft 11 . Protrusions 22 and 23 each protrude toward the outer periphery at positions facing magnet 40 , thereby making the thickness of resin mold portion 50 uniform between inner core 20 and outer core 30 and increasing the thickness of inner core. It also functions as a detent for 20. Moreover, since the protrusions 22 and the protrusions 23 are evenly provided in the circumferential direction with respect to the magnet 40, the magnetic characteristics of the rotor 10 in the circumferential direction can be made uniform.

As shown in FIG. 2, three engaging portions 31 are formed in each of the iron plates 30A that constitute the outer core 30. As shown in FIG. The engaging portion 31 is formed in a concave or convex shape, and the mutually stacked iron plates 30A are engaged at the engaging portion 31, thereby contributing to the positioning of the iron plates 30A in the circumferential direction and the radial direction.

Further, through holes 32 are formed in the iron plate 30A. The through hole 32 forms a cylindrical through hole axially penetrating the stacked iron plates 30A. This cylindrical through-hole corresponds to the column portion 50C of the resin mold portion 50 . In the present embodiment, by providing the column portion 50C of the resin mold portion 50 axially penetrating the outer core 30, the flow path of the resin from the gate to the opposite gate is ensured without increasing the thickness of the resin. and compensate for insufficient resin filling. In addition, since the resin molded portion 50 has the column portion 50C, the entire outer core 30 can be displaced when the resin shrinks during curing. has the effect of

Two protruding portions 33 protruding in the circumferential direction are formed on the outer peripheral portion of the iron plate 30A. As shown in FIGS. 1 and 2, the protruding portion 33 is formed to face the protruding portion 33 of the adjacent iron plate 30A, and is joined to the resin mold portion 50 from the outer peripheral side of the outer peripheral end of the magnet 40. . By securing a distance between the projecting portion 33 (outer core 30) and the magnet 40, the demagnetization resistance of the magnet 40 is improved.

The inner peripheral surface of the iron plate 30A facing the inner core 20 (the iron plate 20A) is formed with a concave portion 35 recessed toward the outer periphery. The recessed portions 35 of the iron plates 30</b>A that are laminated to each other form the groove portion D of the outer core 30 communicating with each other in the axial direction. As shown in FIG. 2, the groove portion D opens toward the inner peripheral side on the inner peripheral surface of the outer core 30 and extends in the axial direction. In the resin flow path 41 indicated by the dotted line in FIG. The thickness of 41 can be made uniform, and there are effects such as suppressing uneven thickness of the resin. In addition, the resin enters the groove portion D, thereby exerting an anchor effect and increasing the force in the radial direction (particularly, the force toward the inside) that holds the outer core 30 . Therefore, the holding strength of the outer core 30 against centrifugal force can be improved.

Next, a method for manufacturing the rotor 10 will be described.

3 to 3A are diagrams showing the process (pressing) of molding the resin mold portion.

As shown in FIG. 3, in the step of molding the resin mold portion 50, for example, a lower mold 61, an upper mold 62, and a lower mold 63 inserted between the lower mold 61 and the upper mold 62 are used. can be used. A wedge-shaped thinning portion piece 65 is attached to the lower mold 61, and a similar wedge-shaped thinning portion piece 66 is attached to the upper mold 62 so as to be slidable in the vertical direction in FIG. A tapered portion 65A and a tapered portion 66A are provided on the thinning portion piece 65 and the thinning portion piece 66, respectively. A member forming a mold is also inserted into the portion corresponding to the magnet 40 .

As shown in FIG. 3A, when the mold is closed, the upper mold 62 is lowered until it abuts against the lower mold 63, and the tapered portion 65A and the tapered portion 66A contact the lower end and the upper end of the outer core 30, respectively. The part piece 65 and the flesh-stealing part piece 66 are slid.

In this state, when resin is filled into the mold and hardened, the inner core 20 and the outer core 30 are fixed by the resin mold portion 50 (FIG. 3B). The resin is filled in the cylindrical through-holes formed by the through-holes 32 of the stacked iron plates 30A from the axial direction (vertical direction), and the column portions 50C axially penetrating the outer core 30 are formed. It is formed.

In FIG. 1, a member having a tapered portion 65A or a tapered portion 66A is combined with another member for enhancing the effect of thinning, thereby forming a thinning portion 67 recessed in a T shape when viewed from the axial direction. An example is shown. Further, in FIG. 1, at two upper and lower positions, the thickness reduction portions 68 are provided in such a shape that the thickness reduction portions 67 are further expanded toward the inner peripheral side. In the thinned portion 68, a thinned portion piece (not shown) that abuts on the outer periphery of the inner core 20 is used to control the radial gap between the inner core 20 and the outer core 30 by the thinned portion piece. can do.

Next, core unit CU is manufactured by inserting magnet 40 into a predetermined portion of resin mold portion 50 .

Next, the rotor 10 is completed by press-fitting the core unit CU manufactured as described above onto the rotating shaft 11 . In the press-fitting step, the inner core 20 is attached to the rotating shaft 11 so that the inner peripheral end of the inner core 20 contacts the outer peripheral end of the rotating shaft 11 . Therefore, as described above, the core unit CU is firmly fixed to the rotating shaft 11, and resistance to strong torque can be ensured.

FIG. 4 is a perspective view showing a case where core units are provided in multiple stages.

In this embodiment, after the core unit CU is manufactured by the pressing process, the core unit CU is attached to the rotating shaft 11 by press fitting. Therefore, not only one core unit CU but also a plurality of core units CU can be sequentially attached to one rotating shaft 11 . For example, in the example of FIG. 4, three core units CU are arranged coaxially with respect to the rotating shaft 11 and attached. Thus, by providing a plurality of core units CU in multiple stages, the torque of the motor can be increased. Cogging torque can be reduced by attaching a plurality of core units CU at different angles in the circumferential direction. Alternatively, while a plurality of core units CU are attached at the same angle in the circumferential direction, the circumferential positions of the teeth of the stator (not shown) are shifted in the axial direction (for example, the teeth are provided in a spiral shape). , the cogging torque can be reduced.

As described above, according to this embodiment, the rotation shaft 11 and the core unit CU (inner core 20) are connected by press-fitting. can be done. Moreover, since a plurality of core units CU can be provided coaxially, it is possible to increase the torque of the motor and reduce the cogging torque.

Although the embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or more of the constituent elements of the above-described embodiments.

In addition, the following additional remarks will be disclosed with respect to the above examples.

[Appendix 1]
An embedded magnet synchronous motor having a rotor (10) with embedded magnets (40), comprising:
The rotor is
a rotating shaft (11);
a core unit (CU) attached to the rotating shaft;
with
The core unit is
an annular inner core (20) attached to the rotating shaft with its inner peripheral end in contact with the outer peripheral end of the rotating shaft;
a plurality of outer cores (30) arranged in the circumferential direction at positions spaced radially outward from the inner core and corresponding to magnetic poles;
a plurality of magnets (40) disposed between the outer cores adjacent to each other and arranged in the circumferential direction;
a resin mold portion (50) joined to the inner core and the outer core;
an embedded magnet synchronous motor.

According to the configuration of Supplementary Note 1, the inner core is attached to the rotating shaft in a state in which the inner peripheral end of the inner core is in contact with the outer peripheral end of the rotating shaft, so the upper limit of torque per core unit is increased. be able to. Moreover, since the outer core and the inner core can be separated from each other by the resin molded portion, magnetic flux leakage from the outer core to the inner core and from the outer core to the rotating shaft can be suppressed.

[Appendix 2]
The embedded magnet synchronous motor according to appendix 1, wherein the inner core is made of a metal material.

According to the configuration of Supplementary Note 2, since the inner core is made of a metal material, the inner core can be attached to the rotating shaft by press-fitting.

[Appendix 3]
The embedded magnet synchronous motor according to appendix 2, wherein the rotating shaft is made of a metal material.

According to the configuration of Supplementary Note 3, since the inner core and the rotating shaft are made of a metal material, the inner core can be firmly attached to the rotating shaft by press-fitting.

[Appendix 4]
The embedded magnet synchronous motor according to any one of Appendices 1 to 3, wherein the inner core is configured by laminating a plurality of plate members (20A) in the axial direction.

According to the configuration of Supplementary Note 4, after laminating a plurality of plate members in the axial direction, the resin molded portion can be formed by resin molding.

[Appendix 5]
The embedded magnet synchronous motor according to any one of Appendices 1 to 4, wherein the resin mold portion is formed along the entire circumference of the core unit on the outer peripheral side of the inner core.

According to the configuration of Supplementary Note 5, since the resin molded portion is formed along the entire circumference of the core unit, magnetic flux leakage from the outer core to the inner peripheral side can be effectively suppressed.

[Appendix 6]
The embedded magnet synchronous motor according to appendix 2, wherein the outer core is made of a metal material different from that of the inner core.

According to the configuration of Supplementary Note 6, the outer core and the inner core can be made of appropriate metal materials, respectively, so that desired performance can be achieved while reducing costs.

[Appendix 7]
comprising a plurality of said core units,
The embedded magnet synchronous motor according to any one of Appendices 1 to 6, wherein the plurality of core units are arranged and attached coaxially with respect to the rotating shaft.

According to the configuration of Supplementary Note 7, since the core units are provided in multiple stages, the torque can be increased. Further, since the core units can be attached to the rotating shaft after the core units are manufactured, the core units can be easily multi-staged.

[Appendix 8]
The embedded magnet synchronous motor according to appendix 7, wherein the plurality of core units are attached at different angles in the circumferential direction.

According to the configuration of Supplementary Note 8, the core units are attached at different angles in the circumferential direction, thereby reducing cogging torque.

[Appendix 9]
The embedded magnet synchronous motor according to any one of Appendices 1 to 8, wherein the inner core is attached to the rotating shaft by being press-fitted into the rotating shaft.

According to the configuration of Supplementary Note 9, since the rotating shaft and the inner core are coupled by press-fitting, the torque upper limit value per core unit can be increased.

REFERENCE SIGNS LIST 10 rotor 11 rotating shaft 20 inner core 30 outer core 20A steel plate 40 magnet 50 resin mold part CU core unit

Claims (9)

An embedded magnet synchronous motor having a rotor with embedded magnets,
The rotor is
a rotating shaft;
a core unit attached to the rotating shaft;
with
The core unit is
an annular inner core attached to the rotating shaft with its inner peripheral end in contact with the outer peripheral end of the rotating shaft;
a plurality of outer cores arranged in the circumferential direction at positions spaced radially outward from the inner core and corresponding to respective magnetic poles;
a plurality of magnets disposed between the outer cores adjacent to each other and arranged in a circumferential direction;
a resin mold portion joined to the inner core and the outer core;
an embedded magnet synchronous motor. 2. The embedded magnet synchronous motor according to claim 1, wherein said inner core is made of a metallic material. 3. The embedded magnet synchronous motor according to claim 2, wherein said rotating shaft is made of a metal material. The embedded magnet synchronous motor according to any one of claims 1 to 3, wherein the inner core is configured by laminating a plurality of plate members in the axial direction. The embedded magnet synchronous motor according to any one of claims 1 to 4, wherein the resin mold portion is formed along the entire circumference of the core unit on the outer peripheral side of the inner core. 3. The embedded magnet synchronous motor according to claim 2, wherein said outer core is made of a metal material different from that of said inner core. comprising a plurality of said core units,
The embedded magnet synchronous motor according to any one of claims 1 to 6, wherein the plurality of core units are arranged and attached coaxially with respect to the rotating shaft. 8. The embedded magnet synchronous motor according to claim 7, wherein said plurality of core units are attached at different angles in the circumferential direction. The embedded magnet synchronous motor according to any one of claims 1 to 8, wherein the inner core is attached to the rotating shaft by being press-fitted into the rotating shaft.

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