JP2020162377A - Electric motor, electric blower with the electric motor, and electric equipment with the electric blower - Google Patents

Abstract

To provide an electric motor in which a sleeve is easily positioned with respect to a rotor core and which has strong magnetic force.SOLUTION: The electric motor has a rotor assembly 300 which comprises: a shaft 301; a cylindrical rotor core 302 fixed to the shaft 301; and a sleeve 303 enclosing the rotor core 302. The rotor core 302 has a magnet molded by mixing an anisotropic material and a resin. The rotor core 302 comprises a plurality of magnetic poles. The rotor core 302 comprises a plurality of projections 302a having the same radial height from the cylindrical surface on the cylindrical surface. The plurality of projections 302a are molded after molding the rotor core 302 and fixed to the rotor core 302.SELECTED DRAWING: Figure 7

Description

The present invention relates to an electric motor, an electric blower equipped with the electric motor, and an electric device provided with the electric blower.

The rotor of an electromechanical machine typically includes a rotor core that is fixed to the shaft, the rotor core contains a magnet, and the magnet is adhered to the shaft. In addition, the rotor core includes a sleeve that surrounds the magnet for the purpose of preventing the magnet from cracking due to the stress generated by the rotation of the rotor and breaking into pieces. The sleeve is fixed to the magnet by adhesion or the like (see, for example, Patent Document 1).

Further, various permanent magnets can be adopted for the rotor core of the electric blower. Bond magnets, which are one of the permanent magnets, are mainly composed of ferromagnetic powder and polymer compounds, and are often manufactured by an injection molding method because of their high productivity. Further, a method for manufacturing an anisotropic magnet, which is formed by magnetizing the outer peripheral surface of a molded product obtained by injection molding in a mold in the same direction as the anisotropic direction (for example, in injection molding) is disclosed. , Patent Document 2).

Japanese Patent No. 5506992 Japanese Patent No. 6371235

The shaft and the permanent magnet (rotor core), and the permanent magnet and the sleeve are respectively bonded via an adhesive. Here, in the process of manufacturing a rotor in which a permanent magnet is bonded to a shaft and a sleeve is bonded to the permanent magnet, the relative positional relationship between the two to be bonded is maintained so as not to change while the adhesive is cured. You need to continue. Therefore, this process requires a long waiting time, which increases the manufacturing cost of the rotor.

Here, the sleeve with respect to the rotor core is formed so as to form a predetermined gap for injecting the adhesive between the outer peripheral surface of the rotor core and the inner peripheral surface of the sleeve to maintain the relative positional relationship between the two. Positioning is important. As a means for facilitating this positioning, it is effective to form a plurality of convex shapes on the cylindrical outer peripheral surface of the rotor core.

By the way, as a means for strengthening the magnetic force of the rotor core, it is effective to adopt an anisotropic bond magnet as the permanent magnet of the rotor core. When the magnetic force of the rotor core is increased, the force for rotating the rotor is increased, and an electric motor capable of high-speed rotation can be obtained. Then, when molding an anisotropic bond magnet for a rotor having a convex shape for positioning on the outer peripheral surface, the anisotropic bond magnet for a rotor is attached in a mold for molding the anisotropic bond magnet for a rotor. In order to create an alignment magnetic field for magnetism, a permanent magnet for generating an alignment magnetic field different from the anisotropic bond magnet for the rotor is required. This permanent magnet for generating an orientation magnetic field needs to be arranged radially outward of the columnar rotor core by the height of the convex shape from the columnar outer peripheral surface of the rotor anisotropic bond magnet, and is oriented. The distance between the permanent magnet for magnetic field generation and the cylindrical outer peripheral surface of the anisotropic bond magnet for the rotor becomes large. As a result, the strength of the orientation magnetic field in the anisotropic bond magnet for the rotor decreases, and in the molding of the anisotropic bond magnet for the rotor, sufficient orientation of the anisotropic material (magnetic powder) cannot be obtained, and the magnetic force becomes There is a problem that it becomes difficult to form a strong anisotropic bond magnet for a rotor.

The present invention has been made to solve the above problems, and is an electric motor capable of facilitating the positioning of the sleeve with respect to the rotor core, obtaining a rotor core having a strong magnetic force, suppressing manufacturing costs, and capable of high-speed rotation. It is an object of the present invention to provide an electric blower equipped with an electric blower and an electric device equipped with the electric blower.

The electric motor according to the present invention has a rotor assembly including a shaft, a cylindrical rotor core fixed to the shaft, and a sleeve that encloses the rotor core, and the rotor core is a mixture of an anisotropic material and a resin. The rotor core has a plurality of magnetic poles, and the rotor core has a plurality of convex portions on the cylindrical surface having the same radial height from the cylindrical surface. After the rotor core is molded, it is molded using the rotor core and is fixed to the rotor core.

According to the present invention, a plurality of convex portions provided on the outer periphery of the rotor core make it easy to position the sleeve with respect to the rotor core, and a rotor core having a magnet having a strong magnetic force is provided to obtain an electric motor capable of high-speed rotation. be able to.

It is external perspective view of the electric blower provided with the electric motor of Embodiment 1. FIG. FIG. 5 is a view of an electric blower including the electric motor of the first embodiment as viewed from the axial direction on the rotor assembly side. FIG. 2 is a cross-sectional view taken along the line AA of FIG. It is sectional drawing which is parallel to the axis of the rotor assembly in the electric motor of Embodiment 1 and passes through the center of the axis. It is external perspective view of the stator in the electric motor of Embodiment 1. FIG. It is a side view of the rotor subassembly which removed the sleeve, a pair of bearings and a preload part from the rotor assembly in the electric motor of Embodiment 1. FIG. It is sectional drawing in line BB of FIG. It is a partially enlarged view of the part C of FIG. It is sectional drawing in the direction perpendicular to the axis at the stage of molding a rotor core in the electric motor of Embodiment 1. FIG. 5 is a cross-sectional view in a direction perpendicular to the axis at the stage of molding a plurality of convex portions of the rotor core in the electric motor of the first embodiment with a mold. FIG. 5 is a cross-sectional view in a direction perpendicular to the axis at the stage of molding a rotor core in an electric motor different from the first embodiment with a mold. It is a side view of the rotor assembly in the electric motor of Embodiment 2. It is sectional drawing which is parallel to the axis of the rotor assembly in the electric motor of Embodiment 2 and passes through the center of the axis. It is a side view of the rotor core in the modification of the electric motor of Embodiment 2. It is a side view of the rotor core in another modification of the electric motor of Embodiment 2.

Hereinafter, embodiments will be described with reference to the drawings. The same reference numerals in each figure indicate the same part or the corresponding parts. In the present disclosure, duplicate description will be simplified or omitted as appropriate. It should be noted that the present invention may include any combination of configurations disclosed in each of the following embodiments. In addition, the shape, material, manufacturing method, and the like described in the present disclosure can be appropriately selected even if not explicitly stated, as long as they do not contradict the outline of the present invention.

Unless otherwise specified in the present disclosure, the axial direction is a direction parallel to the longitudinal direction of the shaft 301 shown in FIG. 6 described later. Further, the radial direction is a direction perpendicular to the axial direction and passing through the center of the shaft 301.

Embodiment 1.
1 to 3 are an electric blower 100 in which an impeller 101 is attached as a load portion to the electric motor 1 according to the first embodiment, and FIG. 1 is an external perspective view of the electric blower 100 including the electric motor 1 of the first embodiment. Is. FIG. 2 is a view of the electric blower 100 including the electric motor 1 of the first embodiment as viewed from the axial direction on the rotor assembly 300 side, which will be described later. FIG. 3 is a cross-sectional view of the electric blower 100 including the electric motor 1 of the first embodiment, and shows a cross-sectional view taken along the line AA of FIG. The cross section on the AA line is a cross section that passes through the central axis of the shaft 301 of the electric blower 100.

As an example, the electric motor 1 is a brushless type electric motor. The electric motor 1 rotates at a rated rotation speed of 100,000 [r / min], for example. Further, the range of possible rotation speeds may be 30,000 to 120,000 [r / min].

The electric motor 1 includes a frame 200. The frame 200 is a member that forms the outer shell of the electric motor 1. The shape of the frame 200 includes, for example, a first cylindrical portion 200a and a second cylindrical portion 200b. The diameter of the first cylindrical portion 200a is smaller than that of the second cylindrical portion 200b. That is, the frame 200 has a stepped cylindrical shape, and one end side of the frame 200 is thinner than the other end side. Further, the second cylindrical portion 200b is provided with an opening 200c on the opposite side of the first cylindrical portion 200a. The frame 200 is made of, for example, an aluminum alloy.

The electric motor 1 includes a rotor assembly 300 and a stator 400. FIG. 4 is a cross-sectional view taken along the shaft 301 of the rotor assembly 300 in the electric motor 1 of the first embodiment and passing through the central axis of the shaft 301. FIG. 5 is an external perspective view of the stator 400 in the electric motor 1 of the first embodiment.

The rotor assembly 300 includes a shaft 301, a cylindrical rotor core 302 fixed to the shaft 301, a sleeve 303 that encloses the rotor core 302, a first end cap 304, a second end cap 305, a pair of bearings 306, and a pair of bearings 306. It has a preload unit 307. The preload unit 307 applies preload to each of the pair of bearings 306. The preload portion 307 includes, for example, a preload spring 307a, a cushion rubber 307b, and a spacer 307c. The preload unit 307 is not limited to the configuration shown here. For example, only the preload spring 307a may be configured.

In the stator 400, the winding 402 is wound around the stator core 401 in which thin sheet electromagnetic steel plates are laminated, and the terminal wire 402a of the winding 402 is electrically connected to the terminal 404. The stator core 401 and winding 402 are electrically insulated by an insulating member 403. In addition to the connections shown here, the connection between the terminal line 402a and the terminal 404 may be a connection by soldering, a connection by fusing, a connection by a bite terminal, or the like. When a current flows through the terminal 404, the stator 400 generates a magnetic flux. Then, this magnetic flux acts on the rotor core 302 as a force for rotating the shaft 301 with respect to the permanent magnet described later, which is fixed to the rotor core 302.

As shown in FIGS. 3 and 4, the pair of bearings 306 and preload portion 307 of the rotor assembly 300 are housed in the first cylindrical portion 200a of the frame 200, and a portion of the rotor assembly 300 and the stator 400 are of the frame 200. It is housed in the second cylindrical portion 200b. It is desirable that at least one of the pair of bearings 306 of the rotor assembly 300 is fixed to the inner peripheral surface of the first cylindrical portion 200a of the frame 200 via an adhesive or the like. Preventing the rotor assembly 300 from slipping out of the first cylindrical portion 200a of the frame 200 by fixing at least one of the pair of bearings 306 to the inner peripheral surface of the first cylindrical portion 200a of the frame 200. Can be done. As the adhesive, for example, a two-component reaction type or an anaerobic adhesive is used. The stator 400 is fixed to, for example, the second cylindrical portion 200b of the frame 200 by tightening. For example, the frame 200 is heated to expand the second cylindrical portion 200b of the frame 200 by thermal expansion, the stator 400 is inserted through the opening 200c, and then the cylindrical portion 200b of the frame 200 contracts due to cooling, so that the frame 200 Tightens and fits the stator 400.

The stator 400 is provided so as to surround the rotor core 302. The axial center of the rotor core 302 is the magnetic center of the rotor core 302, and the axial center of the stator core 401 is the magnetic center of the stator core 401. The magnetic center of the rotor core 302 means that the intensity distribution in the axial direction of the shaft 301 is symmetrical with respect to the intensity distribution of the magnetic field lines generated by the rotor core 302. Similarly, the magnetic center of the rotor core 302 means that the intensity distribution in the axial direction of the shaft 301 is symmetrical with respect to the intensity distribution of the magnetic field lines generated by the rotor core 302. The rotor core 302 and the stator core 401 are configured so that the magnetic center of the rotor core 302 and the magnetic center of the stator core 401 coincide with each other.

The rotor core 302 and the stator core 401 are configured so that the magnetic centers of the rotor core 302 and the magnetic centers of the stator core 401 coincide with each other, but they may not coincide with each other. For example, the magnetic center of the rotor core 302 may be closer to the opening side of the frame 200 (opposite to the impeller 101 side) than the magnetic center of the stator core 401. In the rotor core 302, a force acts from the stator core 401 in a direction in which the magnetic center of the rotor core 302 and the magnetic center of the rotor core 302 coincide with each other. For example, when the magnetic center of the rotor core 302 is on the opening side of the frame 200 (opposite side of the impeller 101 side) from the magnetic center of the stator core 401, the rotor core 302 is on the opposite side of the opening of the frame 200. That is, the force is received on the impeller 101 side. That is, the rotor core 302 acts to press the entire rotor assembly 300 against the impeller 101 side. Therefore, the rotor assembly 300 is prevented from falling out of the frame 200.

Conversely, when the magnetic center of the rotor core 302 is closer to the impeller 101 than the magnetic center of the stator core 401, the rotor core 302 receives a force on the opening side of the frame 200. On the other hand, due to the rotation of the impeller 101, the rotor assembly 300 receives a force on the impeller 101 side. As described above, the force acting on the rotor core 302 due to the deviation of the magnetic center between the rotor core 302 and the stator core 401 acts to cancel the force acting on the rotor core 302 due to the rotation of the impeller 101, and thus the rotor assembly. The force that pushes the entire 300 toward the impeller 101 side is relaxed.

The shaft 301 is a member that serves as a rotation shaft of the electric motor 1, and for example, structural carbon steel, martensitic stainless steel having a higher hardness, or the like is used. Further, considering the use of a magnetic field orientation mold, non-magnetic austenitic stainless steel or the like may be used. The shaft 301 is arranged in the central portion of the internal space of the frame 200. The rotor core 302 is fixed to the shaft 301 by, for example, an adhesive or integral molding described later. Further, the pair of bearings 306 are attached to the shaft 301 by, for example, tightening. The shaft 301 is rotatably supported with respect to the frame 200 via a bearing 306. The rotor core 302 is formed by a permanent magnet. The permanent magnet referred to here may be, for example, a plastic magnet formed by injection molding or compression molding of a mixture of powder and resin of a rare earth magnet such as neodymium Nd and samarium-cobalt Sm2Co17. The rotor core 302 has a plurality of magnetic poles. The rotor core 302 is a member that transmits the magnetic force received from the stator 400 to the shaft 301. The rotor core 302 is formed in a cylindrical shape, for example. The rotor core 302 is fixed to the outer peripheral surface of the shaft 301. The rotor core 302 made of a plastic magnet and the shaft 301 can be integrally molded. When the rotor core 302 and the shaft 301 are fixed by integral molding, it is desirable that the outer peripheral surface of the shaft 301 is knurled.

The first end cap 304 and the second end cap 305 are substantially cylindrical members, and their inner peripheral surfaces are fixed to the outer peripheral surface of the shaft 301. The first end cap 304 and the second end cap 305 are fixed to the shaft 301 by press fitting or an adhesive. When the rotor core 302 and the shaft 301 are integrally formed, the rotor core 302 is fixed to the shaft 301, and then the first end cap 304 and the second end cap 305 are fixed to the shaft 301. If the rotor core 302 and the shaft 301 are adhered and the first end cap 304 and the second end cap 305 are also adhered, they may be adhered at the same time.

The first end cap 304 and the second end cap 305 prevent the pieces of the permanent magnet from scattering in the axial direction when the rotor core 302 is broken. Further, each end cap is connected to the rotor core 302 directly, or via an adhesive or a connecting portion 302c described later. Since the deformation / distortion of the rotor core 302 due to the centrifugal force when the rotor assembly 300 is rotating is suppressed by the respective end caps 304 and 305, the rotor core 302 is less likely to crack. Further, in order to adjust the mass imbalance described later, it is arranged at both ends of the rotor core 302, and it is possible to correct two surfaces. Dynamic imbalance (dynamic mass imbalance) is improved by the two-sided correction. The first end cap 304 and the second end cap 305 may have, for example, a stepped cylindrical shape on the outer peripheral surface. The first end cap 304 and the second end cap 305 are non-magnetic materials.

The first end cap 304 is arranged between the rotor core 302 and the bearing 306. The second end cap 305 is arranged on the opposite side of the first end cap 304 with respect to the rotor core 302. The side surface of the rotor core 302 on the impeller 101 side and the side surface of the first end cap 304 facing the same, the side surface of the rotor core 302 opposite to the impeller 101 and the side surface of the second end cap 305 facing the same come into contact with each other. The first end cap 304 and the rotor core 302, or the second end cap 305 and the rotor core 302 may be arranged with a gap. When the sleeve 303 is adhered to the rotor core 302, the adhesive can be impregnated in the gap between the first end cap 304 and the rotor core 302 or the gap between the second end cap 305 and the rotor core 302.

The rotor assembly 300 has a mass imbalance, such as when the center of gravity of the rotor core 302 is not on the axis of the shaft 301 or when the shaft 301 has a slight bend. The mass imbalance generates a radial force when the rotor assembly 300 is supported by a pair of bearings 306 and rotates. This radial force causes excessive swing of the rotor assembly 300 and excessive stress inside the pair of bearings 306, which deteriorates the performance of the electric blower 100. By measuring the mass imbalance of the rotor assembly 300 and cutting a part of the first end cap 304 and the second end cap 305 at an appropriate position, the mass imbalance of the rotor assembly 300 is reduced.

The sleeve 303 is a member that covers the outer circumference of the rotor core 302. The sleeve 303 is, for example, a cylindrical member. The sleeve 303 is a member for fixing the rotor core 302. In this embodiment, the sleeve 303 covers the entire outer circumference of the rotor core 302. Alternatively, the sleeve 303 covers a part of the outer circumference of the first end cap 304 and a part of the outer circumference of the second end cap 305. For example, when the second end cap 305 has a stepped cylindrical shape as shown in FIG. 4, the sleeve 303 covers the small diameter portion of the second end cap 305 and abuts at the stepped portion with the large diameter portion for positioning. be able to. It is fixed to the rotor core 302, the sleeve 303 and the adhesive.

The sleeve 303 of this embodiment is a non-magnetic material. As an example, the sleeve 303 is formed of a composite material containing carbon fiber and resin. The composite material containing carbon fiber and resin is an example of a material having light weight, high strength and heat resistance.

The electric blower 100 includes an electric motor 1, an impeller 101, a diffuser 102, a bracket 201, and a cover 202. The impeller 101 is a member that generates an air flow that is sucked from the cover 202 side toward the inside of the electric blower 100 by rotating. The impeller 101 is fastened to the shaft 301 with a nut or the like. The bracket 201 and the cover 202 are members that form a part of the outer shell of the electric blower 100. The cover 202 is fitted with the outer peripheral surface of the bracket 201 on the inner peripheral surface. The inner peripheral surface of the cover 202 and the outer peripheral surface of the bracket 201 are fixed by an adhesive.

As shown in FIG. 3, the impeller 101 is attached to a portion of the shaft 301 that protrudes outward on one end side of the frame 200. In this embodiment, the pair of bearings 306 are arranged between the impeller 101 and the rotor core 302. The arrangement of the impeller 101, the pair of bearings 306, and the rotor core 302 is not limited to this arrangement. For example, one bearing 306 may be arranged in the axial direction on the impeller 101 side with respect to the rotor core 302, and the other bearing 306 may be arranged in the axial direction on the opposite side of the impeller 101 with respect to the rotor core 302.

The bracket 201 is attached to one end side of the frame 200. The bracket 201 is provided so as to surround the first cylindrical portion 200a of the frame 200. The cover 202 is fitted with the outer peripheral surface of the bracket 201 on the inner peripheral surface. The inner peripheral surface of the cover 202 and the outer peripheral surface of the bracket 201 are fixed by an adhesive. The cover 202 is provided so as to cover the impeller 101. On one end side of the cover 202, an intake port 202a is formed on the cover 202 on the windward side with respect to the impeller 101. A diffuser 102 is attached to one end side of the bracket 201. A blade row is formed in the diffuser 102, and a plurality of flow paths are formed on the inner surface of the cover 202.

Further, an exhaust port 201a is formed on the other end side of the bracket 201. The exhaust port 201a is provided outside the shaft 301 in the radial direction with respect to the intake port 202a. The exhaust port 201a is provided outside the shaft 301 in the radial direction with respect to the frame 200. The electric blower 100 takes in air from the intake port 202a and sends out air from the exhaust port 201a.

The frame 200, bracket 201, and cover 202 described above are examples of casings that form the outer shell of the electric blower 100. In this embodiment, the rotor assembly 300, the stator 400 and the impeller 101 are housed in this casing. Further, the intake port 202a and the exhaust port 201a are formed in the casing.

Here, with reference to FIG. 3, the air flow during operation of the electric blower 100 will be described. When the electric current is supplied from the terminal 404, the electric blower 100 generates a magnetic flux in which the stator 400 rotates around the shaft 301 with time, and a force for rotating the rotor core 302 is applied to the rotor core 302. As a result, the rotor core 302 and the shaft 301 rotate. Further, the impeller 101 attached to the shaft 301 rotates.

When the impeller 101 rotates, the pressure at the intake port 202a becomes negative. As a result, air is sucked into the cover 202 from the intake port 202a. The sucked air is sent from the central portion of the impeller 101 to the outer circumference. The air sent to the outer circumference of the impeller 101 flows into a plurality of flow paths created by the cover 202 and the diffuser 102. The air flowing through the plurality of flow paths recovers the pressure and improves the blowing performance of the electric blower 100. The air that has passed through the plurality of flow paths flows inside the bracket 201 and is blown out from the exhaust port 201a.

Further, as shown in FIG. 3, a vent 200d may be formed in the frame 200. The vent 200d is an opening that connects the internal space of the second cylindrical portion 200b of the frame 200 and the internal space of the bracket 201. By forming the vent 200d, a part of the air flowing inside the bracket 201 flows into the inside of the second cylindrical portion 200b through the vent 200d. The rotor assembly 300 or the stator 400 is cooled by the air flowing into the second cylindrical portion 200b. The air that has flowed into the inside of the second cylindrical portion 200b is discharged from the opening 200c on the other end side of the frame 200. When the ventilation port 200d is formed, a part or all of the exhaust port 201a may be closed. In that case, a part or all of the air flowing through the bracket 201 flows into the second cylindrical portion 200b, and the cooling effect of the rotor assembly 300 or the stator 400 is improved.

Next, the structure of the rotor assembly 300 according to the first embodiment of the present invention will be described with reference to FIGS. 6 to 8. FIG. 6 is a side view of the rotor subassembly 300a excluding the sleeve of the rotor 300, the pair of bearings 306, and the preload portion 307 in the electric motor 1 of the first embodiment. FIG. 7 is a cross-sectional view perpendicular to the axis of the rotor assembly 300 in the electric motor 1 of the first embodiment, and is a cross-sectional view taken along the line BB of FIG. FIG. 8 is a partially enlarged view of the rotor assembly in the electric blower 100 of the first embodiment, and is a partially enlarged view of the C portion of FIG.

As shown in FIGS. 6 to 8, the rotor core 302 of the rotor subassembly 300a has a plurality of convex portions 302a formed in a straight line parallel to the axial direction of the shaft 301 on its cylindrical outer peripheral surface. The plurality of convex portions 302a have the same height on the cylindrical surface of the rotor core 302 in the radial direction from the cylindrical surface. The plurality of convex portions 302a are provided rotationally symmetrically around the central axis of the shaft 301. The plurality of convex portions 301 are continuously formed on the other end surface (opposite side of the impeller 101) on the other end side in the axial direction of the rotor core 302 which is a magnet. When the sleeve 303 externally encloses the rotor subassembly 300a, the plurality of convex portions 302a come into contact with the inner peripheral surface of the sleeve 303 to form an even gap between the outer peripheral surface of the rotor core 302 and the inner peripheral surface of the sleeve 303. To do. In this way, since the plurality of convex portions 302a are formed in a linear shape parallel to the axial direction of the shaft 301, the outer peripheral surface of the rotor core 302 and the inner peripheral surface of the sleeve 303 are uniformly formed in the axial direction of the shaft 301. A gap can be formed, and the shaft 301 can be prevented from shifting in the axial direction with respect to the adhesive to be filled.

An adhesive (not shown) is filled between the outer peripheral surface of the rotor core 302 and the inner peripheral surface of the sleeve 303. Since the gaps between the two are equal due to the plurality of convex portions 302a and the plurality of convex portions 302a are arranged so as to be rotationally symmetric around the central axis of the shaft 301, the shaft 301 is arranged with respect to the adhesive to be filled. Suppresses the occurrence of mass imbalance due to deviation around the shaft. In the sleeve 303, shear stress acts in the rotational direction of the rotor assembly 300a at the interface between the sleeve 303 and the adhesive due to the angular acceleration of rotation of the rotor assembly 300a and the moment of inertia of the sleeve 303. According to the present embodiment. Since the occurrence of shear stress concentration due to non-uniformity of the adhesive is suppressed, reliability is improved. Further, as compared with the conventional manufacturing process in which positioning and fixing are performed from the outside of the rotor assembly 300 with a jig or the like and curing for a long time is required for curing the adhesive, a jig or the like for positioning and fixing is not required, and a plurality of convex portions 302a are required. Easily obtains even gaps.

As shown in FIG. 6, the plurality of convex portions 302a have a linear shape parallel to the shaft 301 and are shorter than the axial length of the rotor core 302. As a result, the gap formed between the rotor core 302 and the sleeve 303 is not divided into a plurality of spaces by the plurality of convex portions 302a, and becomes one continuous space. For example, when the adhesive is filled after the sleeve 303 is attached to the rotor subassembly 300a, the gap formed between the rotor core 302 and the sleeve 303 becomes one continuous space, so that the injection port of the adhesive to be filled It is not necessary to provide a plurality of adhesives, the manufacturing cost is suppressed, and the non-uniformity of the adhesive due to the deviation of the filling amount is suppressed.

As shown in FIG. 8, the ends of the plurality of convex portions 302a on the impeller 101 side have a slope shape with an angle of D °. Therefore, when the sleeve 303 is attached to the rotor core 302 from the impeller 101 side, the end surface of the sleeve 303 is less likely to be caught by the end of the convex portion 302a, and workability is good.

Next, an example of a method for manufacturing the rotor assembly 300 in the electric blower according to the first embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a cross-sectional view of the method for manufacturing the rotor core 302 in the electric motor 1 of the first embodiment in the direction perpendicular to the shaft 301 at the stage of molding the rotor core 302 with a mold. FIG. 10 is a cross-sectional view in a direction perpendicular to the shaft 301 at the stage of forming the plurality of convex portions 301a of the rotor core 302 in the electric motor 1 of the first embodiment with a mold. FIG. 11 is a cross-sectional view in a direction perpendicular to the shaft 301 at the stage of molding the rotor core 601 of the electric motor different from the electric motor 1 of the first embodiment with a mold.

The rotor core 302 of the first embodiment is a plastic magnet formed by injection molding a mixture of powder and resin of a rare earth magnet. Further, this powder is an anisotropic magnet having an axial direction for easy magnetization. That is, the rotor core 302 has a magnet made of an anisotropic material. By molding in an orientation magnetic field using the powder of an anisotropic magnet, the rotor core 302 has an easy magnetization direction, and the magnetic force per unit volume is higher than that of an isotropic magnet having no easy magnetization direction. Becomes stronger. An electric motor provided with a rotor core made of an anisotropic plastic magnet can achieve high output, or can provide a smaller and lighter electric motor to meet the demand for equivalent output.

FIG. 9 is a diagram schematically showing a cross section of an injection molding die 500 for molding a rotor core 302 on the outer periphery of the shaft 301. In the rotor core 302, a shaft 301 formed by another mold is inserted in advance in the center of the cylindrical mold sleeve 502, and magnetic powder and resin are formed on the inner peripheral side of the mold sleeve 502 and outside the shaft 301. It is molded by filling a mixed material (hereinafter referred to as a plastic magnet compound). The injection molding die 500 includes a plurality of orientation magnets 501 that create a magnetic field in the molding machine. That is, at the time of molding, the rotor core 302 and the plurality of alignment magnets 501 are separated by the mold sleeve 502. The mold sleeve 502 is a non-magnetic material and has a thickness E in the radial direction. The plurality of orientation magnets 501 are arranged outside the mold sleeve 502. The plurality of alignment magnets 501 are arranged around the shaft 301 so that the north pole and the south pole are adjacent to each other. The arrows in FIG. 9 indicate the lines of magnetic force generated by the alignment magnet 501.

When the injection molding mold 500 is filled with the melt-plasticized plastic magnet compound, the anisotropic magnet powder contained in the plastic magnet compound is formed according to the magnetic field generated by the alignment magnet 501. It is oriented in the direction of easy magnetization, which is the direction in which the magnetic moment of the body is easy to direct. The smaller the distance between the alignment magnet 501 and the rotor core 302, the stronger the magnetic force of the alignment magnet 501 acts on the rotor core 302. Here, it is desirable that the thickness E of the mold sleeve 502 is as thin as possible in view of the physical strength, wear resistance, fatigue characteristics, etc. of the mold sleeve 502. That is, the smaller the thickness E of the mold sleeve 502, the stronger the magnetic field generated by the alignment magnet 501 acts on the rotor core 302 to form the rotor core 302 having a large magnetic force, and a high-performance electric motor having higher speed and higher output can be obtained. Be done.

The rotor core 302 of the first embodiment is manufactured by insert molding in which a shaft 301 is inserted into a mold in advance and a molten plastic magnet compound is filled therein. By insert molding the shaft 301 and the rotor core 302, both are integrated, and the manufacturing cost is suppressed as compared with the case where the shaft 301 and the rotor core 302 are fixed by another method such as adhesion.

Further, in FIG. 9, a case where four alignment magnets 501 are used and the rotor core 302 is a magnet having four magnetic poles has been described as an example. Here, the magnetic poles formed in the rotor core 302 are formed of an S pole when the magnetic pole of the alignment magnet 501 facing the rotor core 302 is an N pole, and an N pole when the magnetic pole of the alignment magnet 501 is an S pole. Will be done. The same manufacturing method can be applied even when the number of poles is different.

FIG. 10 is a diagram schematically showing a cross section of an injection molding die 510 for molding a plurality of convex portions 302a on the surface of a cylindrical surface which is an outer peripheral surface of the rotor core 302. The height of the plurality of convex portions 302a in the radial direction is F. When molding the plurality of convex portions 302a, first, the mold sleeve is different from the mold sleeve 502 of the injection molding mold 500 shown in FIG. 9, and is the mold sleeve of the injection molding mold 510. The molded rotor core 302 is inserted into the cylindrical molded portion 511 in advance. Here, a plurality of concave portions for forming the plurality of convex portions 302a are formed on the inner circumference of the molded portion 511. This recess is formed so as to be cut radially outward from the cylindrical surface of the inner surface of the molded portion 511 in the cross section shown in FIG. Then, it is formed so as to extend in the axial direction of the shaft 301. The plurality of convex portions 302a are melt-plasticized in a space surrounded by the outer peripheral cylindrical surface of the rotor core 302 and the concave portions formed so as to be hollowed out in the inner circumference of the molding portion 511 of the injection molding die 510. It is molded by filling. That is, the plurality of convex portions 302a are fixed to the rotor core 302 which is a magnet, and the plurality of convex portions 302a are formed by two-color molding after the rotor core 302 which is a magnet is formed in an orientation magnetic field.

At this time, since the materials of the plurality of convex portions 302a chemically bond with the rotor core 302, the strength of the bonding surface between the two is increased. Further, the resin of the plurality of convex portions 302a may be a resin of a material different from that of the rotor core 302. For example, it may be a resin that does not contain magnet powder. When the material of the plurality of convex portions 302a is a plastic magnet compound, it functions as a magnetic path. As the plastic magnet compound forming the rotor core 302, the case where the powder of the anisotropic magnet is mixed with the resin has been described, but the plastic magnet compound as the material of the plurality of convex portions 302a is the powder of the isotropic magnet. It may be a mixture of bodies. As described above, since the plurality of convex portions 302a are made of a material different from that of the rotor core 302, the degree of freedom in designing the plurality of convex portions 302a is increased.

Here, for comparison, the rotor core 601 in the electric blower different from the first embodiment will be described with reference to FIG. FIG. 11 is a cross-sectional view in a direction perpendicular to the shaft 301 at the stage of molding the rotor core 601 with a mold, which is a method of manufacturing the rotor core 601 in an electric blower different from the first embodiment.

FIG. 11 is a diagram schematically showing a cross section of an injection molding die 700 for molding the rotor core 601. The injection-molded mold 700 includes a mold sleeve 702, and the inner peripheral surface of the mold sleeve 702 is filled with an anisotropic plastic magnet compound to form a rotor core 601 different from that of the first embodiment. Further, the injection molding die 700 includes a plurality of alignment magnets 701. The rotor core 601 different from the first embodiment includes a plurality of convex portions 601a continuous with the rotor core 601.

When the injection molding die 700 is filled with the melt-plasticized plastic magnet compound, the powder of the anisotropic magnet contained in the plastic magnet compound is oriented according to the magnetic field created by the alignment magnet 701. The thickness E of the thin portion of the mold sleeve 702 is preferably as thin as possible in order to manufacture a rotor core having a large magnetic force, but it is the minimum from the physical strength, wear resistance, fatigue characteristics, required life, etc. of the mold sleeve 702. The thickness cannot be less than or equal to E. Further, the plurality of convex portions 601a formed on the rotor core 601 have a height of F radially outward from the cylindrical surface of the rotor core 601. That is, the rotor core 601 in the electric blower different from the first embodiment has an alignment magnetic field formed at a position separated by E + F from the surface of the alignment magnet 701 facing the metal sleeve 702, and is formed in this magnetic field. This is because the rotor core 302 in the electric blower of the first embodiment is separated from the alignment magnet 501 by E by E, the rotor core 601 has a large distance from the alignment magnet 701, and the magnetic force received from the alignment magnet 701 is compared. It means that it is small. As a result, it is difficult to obtain a high-performance electric motor with the rotor core 601 in the electric blower different from the first embodiment.

As described above, since the plurality of convex portions 302a are formed by two-color molding after the rotor core 302 which is a magnet is formed in the orientation magnetic field, the rotor core 302 before the plurality of convex portions 302a are formed is formed. The distance between the magnet and the alignment magnet can be reduced by the height F of the plurality of convex portions, and an electric motor including a magnet having a large magnetic force can be obtained. In addition, the degree of freedom in molding a plurality of convex portions is increased.

As described above, the electric motor according to the first embodiment has a rotor assembly including a shaft, a cylindrical rotor core fixed to the shaft, and a sleeve that encloses the rotor core, and the rotor core is different. It has a magnet formed by mixing a sex material and a resin, the rotor core has a plurality of magnetic poles, and the magnet has a plurality of protrusions having the same radial height from the cylinder surface on the surface of the cylinder. Since the convex portion of the rotor core is molded using the rotor core and is fixed to the magnet, the sleeve can be easily positioned on the outer periphery of the rotor core by the plurality of convex portions without the need for a positioning jig or the like. Will be done. As a result, the sleeve and the rotor core can be easily adhered to each other. Further, since the rotor core excluding the plurality of convex portions is formed before forming the plurality of convex portions, the distance between the rotor core and the alignment magnet before the plurality of convex portions are formed is set to the distance between the plurality of convex portions. It can be reduced by the height, and a rotor core having a magnet having a large magnetic force can be obtained. That is, the plurality of convex portions provided on the outer circumference of the rotor core make it easy to position the sleeve with respect to the rotor core, and since the rotor core having a magnet having a strong magnetic force is provided, it is possible to obtain an electric motor capable of high-speed rotation. In addition, the rotor core can be manufactured by injection molding, and an increase in manufacturing cost can be suppressed.

Further, since the plurality of convex portions are formed in a straight line parallel to the axial direction of the shaft and arranged so as to be rotationally symmetric around the shaft axis, the outer peripheral surface of the rotor core and the inner peripheral surface of the sleeve An even gap can be formed between them in the axial direction of the shaft, and when the gap is filled with an adhesive, it is possible to suppress the occurrence of mass imbalance due to the bias of a plurality of convex portions and the deviation of the adhesive.

Further, since the plurality of convex portions are formed by two-color molding after the rotor core is formed in the alignment magnetic field, the distance between the rotor core and the alignment magnet before the plurality of convex portions are formed is a plurality of distances. It can be reduced by the height of the convex portion, and an electric motor equipped with a magnet having a large magnetic force can be obtained. In addition, the degree of freedom in molding a plurality of convex portions is increased.

Further, the plurality of convex portions are continuously formed on one of the two axial end faces of the rotor core, and the other is not continuous. Since the plurality of convex portions are not continuous with the axial end surface of the rotor core, the gap formed between the outer peripheral surface of the rotor core and the inner peripheral surface of the sleeve is continuous as one space. When filling, the adhesive can be filled in the entire gap without being blocked by the plurality of convex portions. Further, since the plurality of convex portions are continuously formed on one of the two axial end faces of the ter core, the structure of the mold is complicated when the plurality of convex portions are formed in the mold. It can be molded without making it.

Further, since the plurality of convex portions are made of a material different from that of the rotor core, the degree of freedom in designing the plurality of convex portions is increased.

Embodiment 2.
Next, the electric motor according to the second embodiment will be described. The second embodiment will be described focusing on the differences from the electric motor of the first embodiment described above. The same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be simplified and omitted. In the first embodiment, the plurality of convex portions 302a are molded by using the molded rotor core 302 and the molded portion 511 which is a mold sleeve. The second embodiment is different in that the molded rotor core 302 is not used when molding the plurality of convex portions 302b. FIG. 12 is a side view of the rotor assembly 310a in the electric motor 1 of the second embodiment. FIG. 13 is a cross-sectional view taken along the shaft 301 of the rotor assembly 310a in the electric motor 1 of the second embodiment and passing through the center of the shaft 301.

The rotor assembly 310a includes a rotor core 302 fixed to the shaft 301. Further, the cylindrical surface of the rotor core 302 is provided with a plurality of convex portions 302b. Each of the plurality of convex portions 302b is continuous with the connecting portion 302c on the other end side in the axial direction of the rotor assembly 310a. The rotor assembly 310a shown in FIGS. 12 and 13 includes a first end cap 304 on one end side (impeller 101 side) of the rotor core 302.

The rotor assembly 310a of the second embodiment is formed in a magnetic field by an alignment magnet provided in the injection molding die in the same manner as the rotor assembly 300a of the first embodiment, and is formed by a plurality of protrusions in another molding die. A connecting portion 302c continuous with the portion 302b and the plurality of convex portions 302b is integrally formed with the rotor core 302. That is, the plurality of convex portions 302b are formed by two-color molding after the rotor core 302, which is a magnet, is molded in the orientation magnetic field. When molding the connecting portion 302c and the plurality of convex portions 302b, for example, a resin inflow gate is provided on the axial end surface of the connecting portion 302c, and the resin melted from the resin inflow gate is filled. Since the molten resin is filled from a relatively wide portion and all the plurality of convex portions 302b are continuous, the resin is uniformly filled in all the plurality of convex portions 302b, and stable moldability can be obtained. At the same time, molding defects such as mass imbalance and short shots can be suppressed.

FIG. 14 shows a rotor core in a modified example of the electric motor 1 of the second embodiment. The rotor assembly 310a includes a second end cap 305 on the other end side (opposite side of the impeller 101). The inner diameter of the sleeve 303 and the diameter of the cylinder circumscribing the plurality of convex portions 302b are equal, and are shown by the diameter φG in FIG. The outer diameter of the second end cap 305 is indicated by φH. As shown in FIG. 14, by making φH larger than φG, the end cap 305 functions as the positioning of the sleeve 303.

FIG. 15 shows a rotor core in another modification of the electric motor 1 of the second embodiment. The connecting portion 302c in the rotor assembly 310a has a range having a diameter of φI larger than φG. As shown in FIG. 15, by making φI larger than φG, the connecting portion 302c functions as the positioning of the sleeve 303.

As described above, the electric motor according to the second embodiment has a rotor assembly including a shaft, a cylindrical rotor core fixed to the shaft, and a sleeve that encloses the rotor core, and the rotor core is different. It has a magnet formed by mixing a sex material and a resin, the rotor core has a plurality of magnetic poles, and the rotor core has a plurality of protrusions on the surface of the cylinder having the same radial height from the surface of the cylinder. Since the plurality of convex portions are fixed to the rotor core and have a continuous connection portion with the plurality of convex portions on one end surface in the axial direction of the shaft with respect to the rotor core, the sleeve can be used as a positioning tool or the like by the plurality of convex portions. It is easily positioned on the outer circumference of the rotor core without the need, facilitating adhesion between the sleeve and the rotor core. As a result, the distance between the rotor core and the alignment magnet before the plurality of convex portions are formed can be reduced by the height of the plurality of convex portions, and a rotor core having a magnet having a large magnetic force can be obtained, resulting in high speed. A rotatable electric motor can be obtained. Further, since the plurality of convex portions are in contact with the connecting portion, the resin is uniformly filled in all the plurality of convex portions 302b, stable moldability is obtained, and molding defects such as mass imbalance and short shot are obtained. Can be suppressed.

Further, since the plurality of convex portions are formed in a straight line parallel to the axial direction of the shaft and arranged so as to be rotationally symmetric around the shaft axis, the outer peripheral surface of the rotor core and the inner peripheral surface of the sleeve It is possible to form an even gap in the axial direction of the shaft between the two, and when the adhesive is filled in this gap, it is possible to suppress the occurrence of mass imbalance due to the bias of a plurality of convex portions and the deviation of the adhesive.

Further, since the diameter of the connecting portion is larger than the diameter of the cylinder circumscribing the plurality of convex portions, the connecting portion functions as the positioning of the sleeve.

Further, since the plurality of convex portions are formed by two-color molding after the rotor core is formed in the alignment magnetic field, for example, the material of the plurality of convex portions 302b is used as a plastic magnet compound, and the gold provided with the alignment magnet is provided. By molding in the mold, an integrated product of the connecting portion 302c and the plurality of convex portions 302b having a strong magnetic force can be obtained.

Further, since the plurality of convex portions are made of a material different from that of the rotor core, the degree of freedom in designing the plurality of convex portions is increased.

Further, the electric blower 100 includes an electric motor 1 and an impeller 101. The impeller 101 is fixed to the end of the shaft 301 of the transmitter 1. In the electric motor 1, a rotor core having a magnet having a large magnetic force can be produced by injection molding, and an electric blower having a strong attractive force can be obtained while suppressing an increase in manufacturing cost.

As an example of the electric device, it can be applied to an electric vacuum cleaner equipped with an electric blower 100 having an electric motor 1, a hand drying device, and the like. In the electric motor 1 of the electric blower 100 provided in the electric device, a rotor core having a magnet having a large magnetic force can be produced by injection molding, and an electric device having a strong attractive force and a strong wind force can be obtained while suppressing an increase in manufacturing cost.

1 Electric motor,
100 electric blower,
101 Impera,
102 diffuser,
200 frames,
200a First cylindrical part,
200b First cylindrical part,
200c opening,
200d vent,
201 bracket,
201a Exhaust port,
202 cover,
202a Intake,
300 rotor assembly,
300a rotor subassembly,
301 shaft,
302 rotor core,
302a convex part,
302b convex part,
302c connection,
303 sleeve,
304 First end cap,
305 Second end cap,
306 bearing,
307 Preload section,
307a Preload spring,
307b Cushion rubber,
307c spacer,
310a rotor assembly,
400 stator,
401 stator core,
402 windings,
402a terminal line,
403 Insulation member,
404 terminal,
500 injection mold,
501 oriented magnet,
502 mold sleeve,
510 injection mold,
601 rotor core,
700 injection mold,
701 Oriented magnet,
702 mold sleeve.

Claims (12)

It has a rotor assembly comprising a shaft, a cylindrical rotor core fixed to the shaft, and a cylindrical sleeve that encloses the rotor core.
The rotor core has a magnet formed by mixing an anisotropic material and a resin.
The rotor core has a plurality of magnetic poles and has a plurality of magnetic poles.
The rotor core has a plurality of protrusions having the same radial height from the cylindrical surface on the cylindrical surface.
The plurality of convex portions are an electric motor that is formed by using the rotor core after molding the rotor core and is fixed to the rotor core. The electric motor according to claim 1, wherein the plurality of convex portions are formed in a straight line parallel to the axial direction of the shaft, and are arranged so as to be rotationally symmetric around the shaft of the shaft. The electric motor according to claim 1 or 2, wherein the plurality of convex portions are formed by two-color molding after the rotor core is molded in an orientation magnetic field. The electric motor according to claim 3, wherein the plurality of convex portions are continuously formed on one of the two axial end faces of the rotor core, and the other is not continuous. The electric motor according to any one of claims 1 to 4, wherein the plurality of convex portions are made of a material different from that of the rotor core. It has a rotor assembly comprising a shaft, a cylindrical rotor core fixed to the shaft, and a cylindrical sleeve that encloses the rotor core.
The rotor core has a magnet formed by mixing an anisotropic material and a resin.
The rotor core has a plurality of magnetic poles and has a plurality of magnetic poles.
The rotor core has a plurality of protrusions having the same radial height from the cylindrical surface on the cylindrical surface.
The plurality of protrusions are fixed to the rotor core and
It has a connection portion fixed to one end face of the shaft in the axial direction with respect to the rotor core.
The plurality of convex portions are electric motors that are continuous with the connecting portions. The electric motor according to claim 6, wherein the plurality of convex portions are formed in a straight line parallel to the axial direction of the shaft, and are arranged so as to be rotationally symmetric around the shaft of the shaft. The electric motor according to claim 6 or 7, wherein the diameter of the connecting portion is larger than the diameter of the cylinder circumscribing the plurality of convex portions. The electric motor according to any one of claims 6 to 8, wherein the plurality of convex portions are formed by two-color molding after the rotor core is molded in an orientation magnetic field. The electric motor according to any one of claims 6 to 9, wherein the plurality of convex portions are made of a material different from that of the rotor core. The electric motor according to any one of claims 1 to 10, and an electric blower having an impeller. An electric machine having the electric blower according to claim 11.

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