JP2021083242A - Slotless electric motor, electric blower, and vacuum cleaner - Google Patents

Abstract

To provide a slotless electric motor, an electric blower, and a vacuum cleaner that can hold a coil at a low cost and that are compact and highly efficient.SOLUTION: An inner wall surface 50a of an end bracket 50 has protruding portions 530A, 530B that protrude toward an axial direction A. A bobbin 210 has an inner peripheral wall 211 that separates a coil 220 from a rotor 30 on a surface facing the rotor 30. The inner peripheral wall 211 is retained by the protruding portions 530A, 530B.SELECTED DRAWING: Figure 1

Description

The present invention relates to a slotless motor for high-speed rotation, an electric blower equipped with the slotless motor, and an electric vacuum cleaner.

As for electric motors, the rotation speed of electric motors is increasing for the purpose of reducing the size and weight of mechanical devices. In particular, cordless vacuum cleaners, whose demand has been rapidly increasing in recent years, are equipped with brushless electric motors with a speed of 80,000 rpm or more in order to reduce the fan diameter and weight of electric blowers. However, when the speed of the electric motor is increased, the iron loss generated in the core and the mechanical loss generated in the bearing increase. Further, when the motor is miniaturized, the amount of heat generated per volume increases, while the heat dissipation area decreases and the temperature rises. All of these lead to a decrease in motor efficiency, which poses an issue for further speeding up.

A slotless motor is known as a means for reducing iron loss. In a normal slot-type motor, since the core is formed of an annular yoke and a teeth portion protruding toward the rotor side, a large iron loss occurs in the teeth portion where magnetic flux is concentrated. On the other hand, in the slotless type motor, the core is formed only by the annular yoke portion and the teeth portion does not exist, so that the iron loss is relatively small. Further, the slotless type motor has a large magnetic resistance between the rotor and the core. For this reason, it is difficult to increase the magnetic flux density, and it is not suitable for applications that obtain output by torque, but it is suitable for applications such as electric blowers that drive at high speed with relatively small torque and obtain output at rotational speed. is there. However, due to the absence of the teeth portion, (1) positioning and holding of the coil, and (2) securing of a cooling air flow path inside the motor when applied to the motor blower are problems.

Patent Document 1 and Patent Document 2 disclose examples of the structure of a slotless motor. Patent Document 3 discloses an example of the structure of a slot-type electric blower. First, in a normal slot-type motor, the coil is positioned and held by winding the coil around a tooth via an insulator such as a bobbin or insulating paper, but in a slotless-type motor in which the tooth does not exist, this method is used. I can't get it. Therefore, in Patent Document 1, the coil is held by being integrally resin-molded with the housing or the like. Further, in Patent Document 2, the coil is held by attaching the bobbin to the core by the divided bobbin.

Japanese Unexamined Patent Publication No. 2013-165594 Japanese Unexamined Patent Publication No. 2011-176982 JP-A-2018-105269

However, in the structures described in Patent Document 1 and Patent Document 2, the number of assembly steps increases, the structure becomes complicated, and the cost increases. In addition, there is also a problem that the size of the electric motor is increased due to the newly provided holding portion.

Next, the problems when applying the slot type motor to the electric blower will be described. In a conventional electric blower, a part of the wind generated by an impeller directly connected to a rotating shaft is guided into the motor and used for cooling the core, coil, and bearing. In Patent Document 3, a slot-type electric motor is mounted to provide a large space between the coils and between the coil and the rotor, and the wind can cool the core, the coil, and the bearing by using this as a flow path. On the other hand, in the slotless motors described in Patent Documents 1 and 2, it is necessary to arrange the coils densely between the core and the rotor excluding the gap because there is no tooth for concentrating the magnetic flux. For this reason, it is difficult to provide a cooling flow path such as that of a slot-type motor, and if the air is forcibly ventilated, the pressure loss is large and the efficiency of the electric blower is lowered.

The present invention solves the above-mentioned conventional problems, and includes a slotless electric motor capable of holding a coil at low cost, and having a small size and high efficiency, an electric blower equipped with this electric motor, and an electric blower. The purpose is to provide a vacuum cleaner.

In the present invention, an annular core, a stator having a cylindrical coil wound around a bobbin and arranged adjacent to the core in the radial direction, and a stator having a cylindrical coil arranged in the radial direction of the coil are arranged via a gap in the radial direction of the coil. A rotor, a housing for accommodating the core, the stator, and the rotor, and end plates provided at both ends of the housing in the axial direction to support the rotor via bearings. , And a protrusion protruding in the axial direction is formed on the inner wall surface of the end plate, and the bobbin is a partition wall that separates the coil and the rotor on a surface facing the rotor. The partition is held by the protruding portion.

According to the present invention, it is possible to provide a slotless motor, an electric blower and a vacuum cleaner that can hold a coil at low cost and are compact and highly efficient.

It is sectional drawing of the slotless type motor of 1st Embodiment. It is a perspective view which shows the bobbin which attached the distributed winding coil. It is a perspective view when the bobbin is seen from the axial direction. It is a cross-sectional perspective view of a bobbin. It is a perspective view of the distributed winding coil. It is a perspective view which shows the state which separated the bobbin from the protrusion. It is sectional drawing which shows the slotless type motor of 2nd Embodiment. It is sectional drawing which shows the structure around the protrusion as a comparative example. It is sectional drawing which shows the structure around the protrusion of 2nd Embodiment. It is a partial cross-sectional view which shows the slotless type motor of 3rd Embodiment. It is sectional drawing which shows the electric blower provided with the slotless type motor of 4th Embodiment. It is sectional drawing which shows the electric blower provided with the slotless type motor of 5th Embodiment.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate.
(First Embodiment)
FIG. 1 is a cross-sectional view of the slotless motor of the first embodiment. In the following, the slotless motor 1 will be abbreviated as motor 1 as appropriate.
As shown in FIG. 1, the motor 1 is an inner rotor type slotless motor, and includes a core 10, a stator 20, a rotor 30, a housing 40, and end brackets (end plates) 50 and 50. , Is configured.

The core 10 is made of a cylindrical laminated steel plate. That is, the core 10 is formed in a cylindrical shape as a whole by stacking a plurality of annular electromagnetic steel sheets. Further, the core 10 is fixed to the inner peripheral wall surface 40a of the housing 40 arranged on the outer diameter side.

The stator 20 is configured by winding a coil 220 around a bobbin 210. The bobbin 210 is made of a synthetic resin (insulating) material. Further, the stator 20 is provided between the core 10 and the rotor 30. The coil 220 is, for example, three phases of a 12-slot distributed winding. The details of the bobbin 210 and the coil 220 will be described later.

The rotor 30 is arranged on the inner diameter side of the stator 20 via a gap g. Further, the rotor 30 is configured to have a cylindrical permanent magnet 310 and a shaft 320. Further, the rotor 30 is configured by, for example, pressing the shaft 320 into the permanent magnet 310. Further, both ends of the shaft 320 of the rotor 30 are rotatably supported by the end brackets 50 and 50 via bearings 60 and 60. The permanent magnet 310 is, for example, a four-pole Halbach magnetized magnet.

Further, as the permanent magnet 310, for example, a bond magnet is used. The bond magnet is formed by mixing magnetic powder and resin and injection molding. It has a large electric resistance, suppresses eddy currents generated by a time change of magnet magnetic flux, and can realize highly efficient operation. ..

The housing 40 is made of, for example, a cylindrical synthetic resin and has a tubular body 410 that houses a core 10, a stator 20, and a rotor 30. The tubular body 410 has circular openings 40b and 40b in which both ends in the direction in which the shaft 320 of the rotor 30 extends (hereinafter, referred to as the axial direction A) are open. Further, the length of the housing 40 in the axial direction A is formed to be longer than the length of the core 10, the stator 20, and the permanent magnet 310 in the axial direction A.

The end bracket 50 is made of aluminum or an aluminum alloy, and is provided in openings 40b at both ends of the tubular body 410 in the axial direction A. Further, the end bracket 50 is fixed to the inner peripheral wall surface 40a of the housing 40 (cylinder body 410).

Further, the end bracket 50 is composed of an annular plate member 510. A bearing 60 is provided at the center of the plate member 510 in the radial direction, and the rotor 30 is rotatably supported by the end bracket 50.

The bearing 60 is composed of, for example, a ball bearing. The shaft (rotating shaft) 320 of the rotor 30 is inserted into a through hole 520 formed in the center of the plate member 510, and protrudes from the through hole 520 to the outside of the end bracket 50 (housing 40).

Further, a protruding portion 530A protruding toward the coil 220 is formed on the inner wall surface 50a of the end bracket 50 on one side of the axial direction A (left side in the drawing). The protruding portion 530A is formed so as to project in the axial direction A, and is integrally formed with the end bracket 50. Further, the protruding portion 530A is formed at a position facing the inner peripheral wall 211 (bulkhead) of the bobbin 210.

Further, the protrusion 530A holds the stator 20. Note that holding the stator 20 means that the stator 20 is attached so as not to move in the axial direction A, the circumferential direction, and the radial direction. The protrusion 530A is not limited to being integrally formed with the end bracket 50, and may be made of a separate member.

Further, on the inner wall surface 50a of the end bracket 50 on the other side (right side in the drawing) in the axial direction A, a projecting portion 530B projecting toward the coil 220 is formed similarly to the projecting portion 530A. The protruding portion 530B is formed so as to project in the axial direction A, and is integrally formed with the end bracket 50. Further, the protruding portion 530B is formed at a position facing the inner peripheral wall 211 (bulkhead) of the bobbin 210.

Further, the protruding portion 530B is arranged at a position facing the protruding portion 530A in the axial direction A. Further, the protrusion 530B holds the stator 20. The fact that the stator 20 is held means that the stator 20 does not operate in the axial direction A and the radial direction. The protrusion 530B is not limited to being integrally formed with the end bracket 50, and may be made of a separate member.

FIG. 2 is a perspective view showing a bobbin to which a distributed winding coil is attached. Note that FIG. 2 shows a state in which the coil 220 is wound around the bobbin 210.
As shown in FIG. 2, the bobbin 210 includes an inner peripheral wall 211 and an outer peripheral wall 212 located on the outer peripheral side of the inner peripheral wall 211. A coil 220 is provided between the inner peripheral wall 211 and the outer peripheral wall 212.

The inner peripheral wall 211 is formed in a cylindrical shape and has a peripheral wall surface 2111a facing the rotor 30 (see FIG. 1). The peripheral wall surface 211a has a surface that surrounds the entire periphery of the permanent magnet 310 (see FIG. 1) of the rotor 30.

The outer peripheral wall 212 is configured to include a plurality of substantially square plate portions 212a elongated in the axial direction A. In this embodiment, six plate portions 212a are provided. Further, each plate portion 212a is formed so as to be curved along the outer peripheral surface 211b of the inner peripheral wall 211, and is arranged so as to surround the inner peripheral wall 211. Further, the plate portions 212a adjacent to each other in the circumferential direction are arranged at intervals S in the circumferential direction. The spacing S in the circumferential direction of the other adjacent plate portions 212a is also configured to have the same length.

Further, each plate portion 212a is formed to have the same length as the inner peripheral wall 211 in the axial direction A. Further, positioning ribs 212b extending along the circumferential direction are formed on the outer peripheral surface of each plate portion 212a. The positioning rib 212b positions one end of the core 10 (see FIG. 1) in the axial direction A. Although not shown, a rib for positioning the other end of the core 10 in the axial direction A is formed on the inner peripheral wall surface 40a (see FIG. 1) of the housing 40 (see FIG. 1).

FIG. 3 is a perspective view of the bobbin as viewed from the axial direction. Note that FIG. 3 shows a state in which the axial direction A of the bobbin 210 is oriented sideways. Further, FIG. 3 illustrates the bobbin 210 alone.
As shown in FIG. 3, a plurality of notched recesses 211c (cutout portions) notched in a concave shape are formed at one end of the inner peripheral wall 211 in the axial direction A. These notch recesses 211c are formed at equal intervals in the circumferential direction. Further, the notch recess 211c faces the end of each plate portion 212a of the outer peripheral wall 212 in the radial direction.

Further, the inner peripheral wall 211 is formed with an end surface 211d that abuts on the protruding portion 530A (see FIG. 1) at the end portion in the axial direction A. The end face 211d is formed in a substantially annular shape.

Further, the inner peripheral wall 211 and the outer peripheral wall 212 are joined by the teeth 213. The inner peripheral wall 211, the outer peripheral wall 212, and the teeth 213 are integrally formed by resin molding.

FIG. 4 is a cross-sectional perspective view of the bobbin. Note that FIG. 4 shows a state in which the bobbin 210 is cut at the position of the teeth 213 along the axial direction A.
As shown in FIG. 4, the bobbin 210 includes a teeth 213 that connects the inner peripheral wall 211 and the outer peripheral wall 212. The teeth 213 is elongated in the axial direction A. Further, the length L2 in the axial direction A of the teeth 213 is formed to be shorter than the length L1 in the axial direction A of the plate portion 212a. Further, the teeth 213 is located near the center of the plate portion 212a in the axial direction A. Further, in the teeth 213, the length L3 in the radial direction is set so that a gap in which the coil 220 (see FIG. 1) can be arranged is formed between the inner peripheral wall 211 and the outer peripheral wall 212.

FIG. 5 is a perspective view of the distributed winding coil. Note that FIG. 5 shows a state in which the coil 220 attached to the bobbin 210 is taken out as it is.
As shown in FIG. 5, the coil 220 includes U-phase, V-phase, and W-phase inner peripheral coils 221U, 221V, and 221W, and U-phase, V-phase, and W-phase outer peripheral coils 222U, 222V, 222W. It is composed of.

The inner peripheral coils 221U, 221V, and 221W are formed at intervals of 120 °. The outer peripheral coils 222U, 222V, 222W are formed at intervals of 120 °. One set of inner peripheral coils 221U, 221V, and 221W are arranged on the inner diameter side. One set of outer peripheral coils 222U, 222V, 222W is arranged on the outer diameter side. The in-phase inner peripheral coil 221U and the outer peripheral coil 222U (inner peripheral coil 221V and outer peripheral coil 222V, inner peripheral coil 221W and outer peripheral coil 222W) are electrically connected by a connection portion (not shown).

Further, the outer peripheral coil 222U and the inner peripheral coil 221U are arranged so as to face each other with the radial center interposed therebetween. The outer peripheral coil 222V and the inner peripheral coil 221V are arranged so as to face each other. The outer peripheral coil 222W and the inner peripheral coil 221W are arranged so as to face each other.

The outer peripheral coils 222U, 222V, and 222W on the outer diameter side are wound in a substantially square frame shape so as to straddle the adjacent teeth 213 (see FIG. 3). The inner peripheral coils 221U, 221V, and 221W on the inner diameter side are wound in a substantially square frame shape so as to straddle the adjacent teeth 213 (see FIG. 3). Further, the in-phase inner peripheral coil 221U and the outer peripheral coil 222U (inner peripheral coil 221V and outer peripheral coil 222V / inner peripheral coil 221W and outer peripheral coil 222W) are arranged in a state of being out of phase in the circumferential direction.

Such a distributed winding coil 220 realizes more efficient power conversion in order to increase the utilization rate of the magnet magnetic flux in the slotless type motor 1 in which the magnetic resistance between the magnet and the core is large and the magnet magnetic flux is reduced. be able to.

FIG. 6 is a perspective view showing a state in which the bobbin is separated from the protruding portion. Note that FIG. 6 shows only the inner peripheral wall 211 of the bobbin 210.
As shown in FIG. 6, the protrusion 530A formed on the inner wall surface 50a of one of the end brackets 50 is formed with a ridge portion 531 that is unevenly fitted with the notch recess 211c formed on the inner peripheral wall 211 (partition wall). ing. As described above, the protruding portion 530A has a structure in which the protrusion 530A is unevenly fitted with the inner peripheral wall 211 (partition wall).

Further, the protruding portion 530A is formed with a contact surface 532 with which the end surface 211d of the inner peripheral wall 211 in the axial direction A abuts. When the end surface 211d abuts on the contact surface 532, the inner peripheral wall 211 (bulkhead) is prevented from moving in the axial direction A in the housing 40 (see FIG. 1) (movement is restricted). There is.

Further, in the protruding portion 530A, the cylindrical portion 533 in which the convex portion 531 is not formed is fitted into the inner diameter side of the inner peripheral wall 211. As a result, the inner peripheral wall 211 (bulkhead) does not move in the radial direction as well.

Further, the protruding portion 530B formed on the inner wall surface 50a of the other end bracket 50 is formed with a contact surface 534 with which the end surface 211e opposite to the end surface 211d in the axial direction A of the inner peripheral wall 211 abuts. When the end surface 211e abuts on the contact surface 534, the inner peripheral wall 211 (bulkhead) is prevented from moving in the axial direction A in the housing 40 (see FIG. 1) (movement is restricted). There is.

Further, in the protruding portion 530B, the cylindrical portion 535 on the tip side of the contact surface 534 is fitted into the inner diameter side of the inner peripheral wall 211. As a result, the inner peripheral wall 211 (bulkhead) does not move in the radial direction.

Next, the operation of the electric motor 1 of the first embodiment will be described.
A DC magnetic field is formed by a permanent magnet 310 (see FIG. 1) on the outer diameter side of the rotor 30 (see FIG. 1). On the other hand, when a three-phase electric power converted to a predetermined frequency by an inverter (not shown) is supplied to the coil 220 (see FIG. 1), a rotating magnetic field is formed on the inner diameter side of the stator 20 (see FIGS. 1 and 2). By energizing a current that matches the position of the magnetic poles of the rotor 30, torque is generated by the attraction and repulsion between the rotating magnetic field and the DC magnetic field, and the rotor 30 is rotationally driven. Since the annular core 10 does not have a teeth portion where magnetic flux is concentrated, iron loss is reduced. Therefore, high-efficiency operation with small iron loss can be realized even in a high-speed region.

By the way, in a slotless type motor, unlike a general slot type motor, a bobbin or an insulating paper cannot be attached to the tooth portion of the core, or a coil cannot be wound and held. For this reason, conventionally, methods such as integrating the coil, the core, and the housing with a resin mold, or dividing the bobbin and fixing it to the annular core have been proposed. However, these methods have led to an increase in assembly man-hours, a complicated structure, and an increase in cost. In addition, the addition of a resin mold may increase the size of the motor.

Therefore, in the motor 1 of the first embodiment, the coil 220 can be held by the protrusions 530A and 530B formed on the end brackets 50 and 50 and the inner peripheral wall 211 (bulkhead) of the bobbin 210. Is. Therefore, there is no need to add new parts or increase man-hours, the cost is low, and it is possible to contribute to the miniaturization of the motor 1. As a result, it is possible to realize a compact, high-speed and highly efficient motor 1 that takes advantage of the low iron loss characteristics of the slotless motor. From the above, it is possible to provide a low-cost, compact, and highly efficient slotless motor 1.

The structure (shape) of the protrusions 530A and 530B and the inner peripheral wall 211 (partition wall) may satisfy the positioning function of the coil 220, and the specifications such as the number of poles and the material of the rotor 30 and the stator 20 are as follows. It is not limited to this embodiment. For example, the rotor 30 may be an outer rotor type motor in which the rotor 30 is arranged on the outer circumference of the stator 20. Further, although the distributed winding has been described for the coil 220, a concentrated winding may be used.

Further, in the first embodiment, the protruding portion 530A forming the convex portion 531 on the cylindrical portion 533 (see FIG. 6) has been described as an example, but the convex portion in the circumferential direction without providing the cylindrical portion 533 has been described. The 531 may be formed at intervals. That is, the ridge portion 531 may be formed separately from the inner wall surface 50a in the circumferential direction. Further, the number of ridge portions 531 is not limited to the same as the number of plate portions 212a, and may be less than the number of plate portions 212a or larger than the number of plate portions 212a. Further, the structure is not limited to a quadrangular shape as long as the structure can be fitted with irregularities, and may have other shapes.

Further, in the first embodiment, the case where the structure for unevenly fitting with the inner peripheral wall 211 (partition wall) is provided only on the protruding portion 530A side has been described with an example, but the inner peripheral wall has been described in both the protruding portions 530A and 530B. A structure in which the 211 is unevenly fitted may be adopted. As a result, it is possible to more reliably prevent the inner peripheral wall 211 (stator 20) from rotating in the circumferential direction in the housing 40.

As described above, the electric motor 1 of the first embodiment includes an annular core 10 and a cylindrical coil 220 wound around the bobbin 210 and arranged adjacent to the core 10 in the radial direction. It includes a stator 20 and. Further, the electric motor 1 includes a rotor 30 arranged in the radial direction of the coil 220 via a gap g, and a housing 40 for accommodating the core 10, the stator 20, and the rotor 30. Further, the motor 1 is provided at both ends of the housing 40 in the axial direction A, and includes end brackets 50 and 50 that support the rotor 30 via bearings 60 and 60. The inner wall surface 50a of the end bracket 50 is formed with protrusions 530A and 530B protruding in the axial direction A. The bobbin 210 has an inner peripheral wall 211 (bulkhead) that separates the coil 220 and the rotor 30 from the surface facing the rotor 30. The end portion of the inner peripheral wall 211 in the axial direction A is held by unevenly fitting with the protruding portion 530A. The end portion of the inner peripheral wall 211 in the axial direction A is held by fitting with the protruding portion 530B. According to this, since the addition of new parts and the increase in man-hours are eliminated, the cost is reduced, and the resin mold is not required, so that the motor 1 can be miniaturized. Further, by using the annular core 10, the iron loss is reduced, so that highly efficient operation with a small iron loss is possible even in a high speed region.

Further, in the first embodiment, the coil 220 is composed of distributed windings (see FIGS. 2 and 5). According to this, more efficient power conversion can be realized, and more efficient operation becomes possible.

Further, in the first embodiment, the inner peripheral wall 211 (bulkhead) and the protruding portion 530A are unevenly fitted to each other, so that the inner peripheral wall 211 (bulkhead) is held by the protruding portion 530A (see FIG. 6). According to this, the rotation of the bobbin 210 (stator 20) in the circumferential direction can be suppressed by a simple structure.

Further, in the first embodiment, the projecting portions 530A and 530B have contact surfaces 532 and 534 with which the end faces 211d and 211e of the inner peripheral wall 211 (partition wall) abut in the axial direction A (see FIG. 6). According to this, the movement of the bobbin 210 (stator 20) in the axial direction A can be suppressed by a simple structure.

(Second Embodiment)
FIG. 7 is a cross-sectional view showing the slotless type motor of the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals, and duplicate description will be omitted.
As shown in FIG. 7, in the slotless motor (hereinafter, motor) 1A, protrusions 530C and 530D are provided on end brackets 50 and 50 (end plates) provided at both ends of the housing 40 in the axial direction A. It is a thing. The protrusion 530C is formed on the inner wall surface 50a of one of the end brackets 50. The protrusion 530D is formed on the inner wall surface 50a of the other end bracket 50.

The tip 530t of the protrusion 530C in the axial direction A is located inside the end 220a of the coil 220 in the axial direction A. In other words, the protruding portion 530C is formed so as to extend in the axial direction A to a position where it overlaps the coil 220 in the radial direction.

The tip 530t of the protruding portion 530D in the axial direction A is located inside the end portion 220b of the coil 220 in the axial direction A. In other words, the protruding portion 530D is formed so as to extend in the axial direction A opposite to the protruding portion 530A to a position where it overlaps the coil 220 in the radial direction.

Further, in the motor 1A, the distance to the tip 530t of the protrusion 530C with respect to the base end 530s (inner wall surface 50a) of the protrusion 530C is set to h1, and the end of the coil 220 arranged on the side facing the protrusion 530C. When the distance to the portion 220a is h2, h2 <h1. The distances h1 and h2 are straight lines extending in the axial direction A and are parallel to each other.

Next, the difference in the effect of the above structure will be described with reference to FIGS. 8 and 9. FIG. 8 is a cross-sectional view showing a structure around a protruding portion as a comparative example. FIG. 9 is a cross-sectional view showing the structure around the protrusion of the second embodiment. In the following, the structure around one protrusion in the axial direction A will be described, but since the structure around the other protrusion has the same configuration, only the periphery of one protrusion will be shown and described. ..
The motor 1 as a comparative example shown in FIG. 8 has an end bracket 50 provided with a protrusion 530A. The tip 530t of the protrusion 530A in the axial direction A is located outside the axial direction A (on the inner wall surface 50a side) of the end 220a of the coil 220. In the electric motor 1, the distance to the tip 530t of the protrusion 530A with respect to the base end 530s of the protrusion 530A is set to h1, and up to the end 220a (coil end) of the coil 220 arranged on the side facing the protrusion 530A. When the distance of is h2, h2> h1.

By the way, during the operation of the motors 1 and 1A, a load Fc (see FIGS. 8 and 9) in the inner diameter direction (inside in the radial direction) acts due to the Lorentz force generated in the coil 220. On the other hand, the protrusions 530A and 530C generate a reaction force Fr (see FIGS. 8 and 9) to hold the bobbin 210. However, as shown in FIG. 8, when there is a distance between the position where the bobbin 210 is supported by the protruding portion 530A and the coil 220 (end 220a), a bending force acts on the inner peripheral wall 211 (bulkhead) of the bobbin 210. The bobbin 210 may be pushed toward the inner diameter side. In particular, in the case of a slot-type motor, it is difficult to provide a large gap between the rotor and the bobbin in order to reduce the magnetic resistance between the rotor and the core. In addition, during operation, the rotor diameter increases due to thermal expansion and vibration in the radial direction also occurs. Therefore, if the bobbin is deformed to the inner diameter side, it may collide with the rotor.

On the other hand, as shown in FIG. 9, in the second embodiment, the reaction force Fr in the protruding portion 530C is directly transmitted to the coil 220, so that the deformation of the partition wall (inner peripheral wall 211) of the bobbin 210 is suppressed and the bobbin It is possible to prevent the 210 from colliding with the rotor 30. That is, since the bobbin 210 can be held in the radial direction by the compressive strength rather than the bending strength of the partition wall (inner peripheral wall 211), the radial holding strength of the bobbin 210 is improved. As a result, the reliability against temperature rise and vibration during operation of the motor 1A is improved.

In the motor 1A of the second embodiment, the distance h1 to the tip 530t of the protrusion 530C and the distance h2 to the end 220a of the coil 220 facing the protrusion 530C are different from each other based on the base end 530s of the protrusion 530C. It is configured so that h1> h2 (see FIGS. 7 and 9). According to this, it is possible to prevent the partition wall (inner peripheral wall 211) of the bobbin 210 from being deformed toward the rotor 30 on the inner side in the radial direction, and it is possible to prevent the bobbin 210 from colliding with the rotor 30.

(Third Embodiment)
FIG. 10 is a partial cross-sectional view showing the slotless type motor of the third embodiment.
As shown in FIG. 10, the slotless motor (hereinafter, motor) 1B is provided with a protruding portion 530E protruding inward in the axial direction A on the inner wall surface 50a of the end bracket 50. At the tip of the protrusion 530E, a chamfered portion 530 m formed of an inclined surface inclined in a direction away from the bobbin 210 (inner peripheral wall 211) with respect to the axial direction A is formed on a surface facing the stator 20 side (bulkhead side). Has been done.

By the way, the end portion P of the partition wall (inner peripheral wall 211) of the bobbin 210 may be slightly deformed to the inner diameter side due to the tension of the coil 220 during winding work or the like. If an attempt is made to fit the partition wall (inner peripheral wall 211) of the bobbin 210 and the protruding portion 530E of the end bracket 50 in this state, they interfere with each other (the tips abut against each other in the axial direction A) or the protruding portion 530E or the bobbin. 210 may be damaged. Therefore, in the third embodiment, the chamfered portion 530 m shown in FIG. 10 is provided on the protruding portion 530E in order to improve the assembling property. In the third embodiment, the case where the chamfered portion 530 m is provided on the protruding portion 530E has been described as an example, but the chamfered portion may be provided on the partition wall (inner peripheral wall 211) side, and the protruding portion 530E and the partition wall may be provided. A chamfered portion may be provided on both sides of the above. Even in the case of the configuration in which the chamfered portion 530 m is provided in this way, it is desirable to configure the configuration so that the reaction force Fr is directly transmitted to the coil 220 (h2 <h1, see FIG. 9).

The electric motor 1C of the third embodiment has a chamfered portion 530 m formed of an inclined surface in which the protruding portion 530E is inclined in a direction away from the inner peripheral wall 211 toward the tip 530t of the protruding portion 530E with respect to the axial direction A. According to this, when the stator 20 is attached to the end bracket 50, the interference between the partition wall (inner peripheral wall 211) of the bobbin 210 and the projecting portion 530E can be suppressed, and the projecting portion 530E and the bobbin 210 can be suppressed from being damaged.

(Fourth Embodiment)
FIG. 11 shows a cross-sectional view showing an electric blower equipped with the slotless type motor of the fourth embodiment.
As shown in FIG. 11, the electric blower 100A includes a slotless electric motor (hereinafter, electric motor) 1C and an impeller (impeller, mixed flow fan) 500 directly connected to the shaft 320 of the rotor 30. ing. The core 10, the stator 20, and the rotor 30 of the motor 1C are configured in the same manner as the motor 1A of the second embodiment.

The housing 40A extends in the axial direction A to form an air passage 411 (first flow path) through which air flows. Further, in the housing 40A, an introduction port 411a into which air is introduced is formed at one end of the air passage 411, and an outlet 411b through which air is discharged (exhausted) is formed at the other end of the air passage 411.

Further, in the housing 40A, a communication port 412 for communicating the air passage 411 and the arrangement area R is formed in the arrangement area R of the stator 20 formed by the housing 40A and the inner peripheral wall 211 (partition wall) of the bobbin 210. There is. The arrangement area R means an area in which the core 10 and the stator 20 surrounded by the housing 40A, the end brackets 50, 50, and the stator 20 are arranged.

Further, the end bracket 50 on the side on which the impeller 500 is not mounted has an opening 50b. A plurality of the openings 50b are formed at intervals in the circumferential direction. The outside air (air) is led out (exhausted) from the opening 50b.

Further, an air passage (space) 413 through which air passes is formed between the housing 40A and the core 10. The core 10 is fixed to the inner peripheral wall surface 40a of the housing 40A via, for example, a bracket having a shape capable of forming an air passage 413. As a result, air is introduced into the housing 40A (arrangement region R) from the communication port 412.

The impeller 500 is fixed directly to the shaft 320 and is located outside the end bracket 50. A fan cover 420 is provided on the outer periphery of the impeller 500. The fan cover 420 is attached to the housing 40A. Further, the fan cover 420 includes a suction port 420a formed in front of the impeller 500 in the axial direction A, and a tubular body 420b extending from the suction port 420a toward the housing 40A while expanding its diameter.

The electric blower 10A configured in this way includes an air passage 411 (flow path, first flow path) continuous in the axial direction A from the impeller 500 side to the anti-impeller side. A diffuser (not shown) is provided in the air passage 411. As the diffuser (not shown), a known diffuser can be used. Further, the air passage 411 is provided with a communication port 412 that communicates with the inside of the motor 1C. Further, the end bracket 50 on the anti-impeller side is provided with an opening 50b that communicates with the outside air. A second flow path connecting the opening 50b and the communication port 412 is configured in the motor 1C.

The motor 1C is a stator 20 having an annular core 10 and a substantially annular coil 220 wound around a bobbin 210, and a cylindrical permanent magnet 1C arranged on the inner diameter side of the stator 20 via a gap g. It is an inner rotor type slotless electric motor provided with a rotor 30 having a magnet 310 and a shaft 320 (rotating shaft). The core 10 is fixed to the housing 40A so that an air passage 413 is formed (holding portion is not shown). The end bracket 50 is fixed to the inner peripheral wall surface 40a of the housing 40A.

Here, the end bracket 50 includes protrusions 530C and 530D extending toward the coil 220. The bobbin 210 is provided with a partition wall (inner peripheral wall 211) formed on the inner diameter side of the coil 220 so as to separate the coil 220 and the rotor 30. Further, the protruding portions 530C and 530D are arranged so as to be in contact with the partition wall (inner peripheral wall 211). Further, the protrusion 530C is formed with a ridge portion 531 (see FIG. 6) corresponding to the notch recess 211c (see FIGS. 3 and 4) formed in the partition wall (inner peripheral wall 211). As a result, the ridge portion 531 and the notch recess 211c are unevenly fitted. The structure in which the notch recess 211c and the convex portion 531 are unevenly fitted may be provided not only on the protruding portion 530C side but also on both the protruding portions 530C and 530D.

The operation of the electric blower 100A provided with the slotless motor 1C will be described below. The operation of the slotless motor 1C is the same as the operation described in the first embodiment described above.
When the motor 1C is driven, an air flow is generated by the rotation of the impeller 500. When air is sucked from the suction port 420a (see the solid line arrow af1), it passes between the fan cover 420 and the outer circumference of the impeller 500 (see the solid line arrow af2). Then, the air is introduced from the introduction port 411a into the air passage 411 (first flow path) (see the solid line arrow af3), the pressure is adjusted by a diffuser (not shown), and the air is discharged to the outside of the motor from the outlet port 411b (solid line). See arrow af4). Further, a part of the air introduced from the introduction port 411a enters the arrangement region R from the communication port 412 (see the broken line arrow af5). The air is then discharged from the end bracket 50 through the air passage 414 and through the opening 50b (see dashed arrow af6).

By the way, in a slotless type motor, unlike a general slot type motor, a bobbin cannot be attached to the tooth portion of the core to hold the coil. For this reason, conventionally, methods such as integrating the coil, the core, and the housing with a resin mold, or dividing the bobbin and fixing it to the annular core have been proposed. However, these methods lead to an increase in assembly man-hours, a complicated structure, and an increase in cost. In addition, the physique of the motor may be increased by adding a holding portion for the mold or bobbin. Further, when used for an electric blower, the holding portion may obstruct the flow path for cooling. On the other hand, in the motor 1C of the fourth embodiment, the coil 220 can be held by the protrusions 530C and 530D of the end brackets 50 and 50 and the partition wall (inner peripheral wall 211) of the bobbin 210. Therefore, there is no addition of new parts or an increase in man-hours, the cost is low, the motor 1C can be miniaturized, and the annular core 10 can reduce the iron loss even in the high speed region. As a result, a compact, high-speed, high-efficiency motor that takes advantage of the low iron loss characteristics of the slotless motor 1C can be realized.

Further, the fourth embodiment has the effect of enhancing the cooling performance of the slotless motor 1C. In a general motor, by mounting a slot-type motor using a centralized winding coil, a large gap is provided between the coils and between the coil and the rotor, and a flow path (in the second flow path of the present embodiment) is provided there. By forming the corresponding flow path), a large amount of wind is allowed to flow, and the core, coil, and bearing, which are the main heat sources, are forcibly air-cooled. On the other hand, in the slotless type motor, since the core does not have teeth, it is necessary to densely arrange the coils in the gap between the rotor and the core excluding the gap. Further, as described above, when a distributed winding coil is used in order to increase the utilization rate of the magnetic flux of the magnet, the gap between the coils becomes smaller and the height of the coil end also increases, so that the flow path toward the gap g Narrows and pressure loss increases. On the other hand, in the slotless motor 1C of the fourth embodiment, the opening 50b of the end bracket 50 is provided on the outer peripheral side (the side facing the arrangement region R). Therefore, the flow path to the gap g side is also reduced by the protrusions 530C and 530D and the partition wall (inner peripheral wall 211). Therefore, the wind does not go to the gap g side, and the core 10 and the coil 220 are cooled by the low voltage loss.

The heat of the bearing 60, which is not directly exposed to the wind, is appropriately air-cooled via the aluminum end bracket 50 having high thermal conductivity. Therefore, the core 10, the coil 220, and the bearing 60 can be efficiently cooled without increasing the pressure loss of the air passage 414 (second flow path). As described above, it is possible to provide a compact and highly efficient slotless electric blower 100A having excellent heat dissipation at low cost.

The electric blower 100A provided with the electric motor 1C of the fourth embodiment has a cylindrical coil 220 wound around an annular core 10 and a bobbin 210 and arranged adjacent to the core 10 in the radial direction. The stator 20 provided, the rotor 30 arranged in the radial direction of the coil 220 via the gap g, the housing 40A accommodating the core 10, the stator 20 and the rotor 30, and the axial direction A of the housing 40A. It includes end brackets 50 and 50 provided at both ends and supporting the rotor 30 via a bearing 60, and an impeller 500 directly connected to the shaft 320 of the rotor 30. On the other hand (on the impeller 500 side), the inner wall surface 50a of the end bracket 50 is formed with a protruding portion 530C that protrudes in the axial direction A. On the other side (anti-impeller side), the inner wall surface 50a of the end bracket 50 is formed with a protruding portion 530D that projects in the axial direction A. The bobbin 210 has an inner peripheral wall 211 (bulkhead) that separates the coil 220 and the rotor 30 from the surface facing the rotor 30. The inner peripheral wall 211 (partition wall) is held by the protrusions 530C and 530D. According to this, it is possible to realize a slotless electric blower 100A which is compact and highly efficient at low cost.

Further, in the electric blower 100A, the distance h1 to the tip 530t of the protrusions 530C and 530D and the end 220a of the coil 220 facing the protrusions 530C and 530D are reached based on the base end 530s of the protrusions 530C and 530D. The distance h2 is configured such that h1> h2 (see FIGS. 7 and 9). According to this, it is possible to prevent the partition wall (inner peripheral wall 211) of the bobbin 210 from being deformed toward the rotor 30 on the inner side in the radial direction, and it is possible to prevent the bobbin 210 from colliding with the rotor 30.

Further, in the electric blower 100A, the coil 220 is composed of distributed windings (see FIGS. 2 and 5). According to this, more efficient power conversion can be realized.

Further, in the electric blower 100A, the end bracket 50 is made of a material made of aluminum (aluminum alloy) having a higher thermal conductivity than the housing 40A. According to this, the bearing 60 can be cooled by dissipating the heat of the bearing 60 through the end bracket 50.

Further, the electric blower 100A has an opening 50b in which the end bracket 50 communicates with the arrangement region R of the stator 20 formed by the housing 40A and the inner peripheral wall 211 (partition wall). According to this, the heat transferred from the bearing 60 to the end bracket 50 can be cooled (air-cooled) by the air passing through the opening 50b.

Further, the electric blower 100A is provided with a communication port 412 in which the air passage 411 for passing the air (wind) generated by the impeller 500 is formed in the housing 40A and the air passage 411 and the arrangement area R are communicated with each other. According to this, the core 10, the coil 220, and the bearing 60 can be cooled without increasing the pressure loss of the air passage 414 (the flow path formed between the communication port 412 and the opening 50b).

Further, in the electric blower 100A, since the flow path to the gap g side is reduced by the protrusions 530C and 530D and the partition wall (inner peripheral wall 211), the wind does not go to the gap g side, and the core 10 and the coil 220 are subjected to low pressure loss. Can be cooled.

(Fifth Embodiment)
FIG. 12 is a cross-sectional view showing an electric blower including the slotless type motor of the fifth embodiment.
As shown in FIG. 12, the electric blower 100B includes a slotless electric motor (hereinafter, electric motor) 1D and an impeller (axial fan) 600 directly connected to the shaft 320 of the rotor 30. The core 10, the stator 20, and the rotor 30 of the motor 1D are configured in the same manner as the motor 1A of the second embodiment.

The housing 40B extends in the axial direction A to form an air passage 431 through which air flows. Further, in the housing 40B, an introduction port 431a into which air is introduced is formed at one end of the air passage 431, and an outlet 431b through which air is led out is formed at the other end of the air passage 431.

Further, the end bracket 50 on the side on which the impeller 600 is not mounted has an opening 50b. A plurality of the openings 50b are formed at intervals in the circumferential direction. The outside air (air) is taken out (exhausted) from the opening 50b.

Further, the end bracket 50 on the side on which the impeller 600 is mounted has an opening 50c. A plurality of the openings 50c are formed at intervals in the circumferential direction. The outside air (air) is introduced into the arrangement region R from the opening 50c. In this way, an air passage (second flow path) is formed so that air flows from the opening 50c to the opening 50b.

The impeller 600 is fixed directly to the shaft 320 and is located outside the end bracket 50. A fan cover 440 is provided on the outer periphery of the impeller 600. The fan cover 440 includes a suction port 440a formed on the front surface of the impeller 600 in the axial direction A, and a tubular body 440b extending from the suction port 440a toward the housing 40B.

The electric blower 100B provided with the electric motor 1D configured as described above includes an air passage 431 (flow path, first flow path) continuous in the axial direction A from the impeller 600 side to the anti-impeller side. A diffuser (not shown) is provided in the air passage 431. As the diffuser (not shown), a known diffuser can be used. The air passage 431 functions as a flow path for discharging the sucked air to the outside of the electric blower 100B in the electric blower 100B (see solid arrows af11 and af12). Further, the electric blower 100B includes an air passage 434 (second flow path) through which air passes on the inner diameter side of the housing 40B.

The electric motor 1D has an annular core 10 and a stator 20 having a substantially annular coil 220 wound around a bobbin 210, and is arranged on the inner diameter side of the stator 20 via a gap g, and has a cylindrical permanent shape. It is an inner rotor type slotless electric motor provided with a rotor 30 having a magnet 310 and a shaft 320 (rotating shaft). The core 10 is fixed to the housing 40B so that an air passage 413 is formed (holding portion is not shown). The end bracket 50 is fixed to the housing 40B.

In the electric blower 100B configured in this way, the cooling air (air flow) of the motor 1D is the end bracket 50 on the impeller 600 side (see the broken line arrow af13) → the coil end 220s → the core 10 → the coil end 220t on the anti-impeller side → It flows with the end bracket 50 on the anti-impeller side (see the dashed arrow af14). Therefore, since the bearing 60 on the impeller 600 side and the coil end 220t can be cooled, the average temperature of each component can be reduced and the temperature distribution in the axial direction A in the motor 1D can be made uniform.

The shapes of the protruding portions 530C and 530D and the partition wall (inner peripheral wall 211) may satisfy the functions of coil positioning and pressure loss reduction, and the motors 1C and 1D such as the number of poles and materials of the rotor 30 and the stator 20 may be satisfied. The specifications, the shape of the impeller, and the entrance position of the second flow path are not limited to this embodiment. For example, the coil 220 may use centralized winding. Further, the housings 40A and 40B may be divided in the axial direction and the radial direction. The materials of the housings 40A and 40B and the end bracket 50 may have a thermal conductivity of housing <end bracket. Further, although the boundary position between the housings 40A and 40B and the end bracket 50 is arbitrary, it is important to provide an opening 50b in the highly heat conductive end bracket 50 in order to efficiently dissipate the heat of the bearing 60.

Further, by applying the electric blowers 100A and 100B of the above-described embodiment to the vacuum cleaner, it is possible to realize a small vacuum cleaner having a high suction force. For example, the vacuum cleaner can be applied to various types such as a handy type, a stick type, a canister type, and a robot type.

1,1A, 1B, 1C, 1D Slotless motor 10 core 20 stator 30 rotor 40, 40A, 40B housing 50 end bracket (end plate)
50a Inner wall surface 50b, 50c Opening 60 Bearing 100A, 100B Electric blower 210 Bobbin 211 Inner peripheral wall (bulkhead)
211c Notched recesses 211d, 211e End face 212 Outer wall 212a Plate 213 Teeth 220 Coil 220a End (coil end)
221U, 221V, 221W Inner coil 222U, 222V, 222W Outer coil 310 Permanent magnet 320 Shaft (rotating shaft)
410 Cylinder body 411,431 Air passage (first flow path)
411a Inlet port 411b Outlet port 412 Communication port 413,414 Air passage (second flow path)
420,440 Fan cover 434 Air passage (second flow path)
500,600 impeller (impeller)
530A, 530B, 530C, 530D Protruding part 531 Convex part 532,534 Contact surface 533,535 Cylindrical part 530m Chamfering part 530s Base end 530t Tip (protruding tip)
A-axis direction (rotation axis direction)
g Gap h1 Distance to the tip of the protrusion with reference to the base end of the protrusion h2 Distance to the tip of the coil facing the protrusion with reference to the base end of the protrusion Fr Anti-force acting on the coil Force R placement area

Claims (14)

With an annular core,
A stator with a cylindrical coil wound around a bobbin and placed adjacent to the core in the radial direction.
With the rotor arranged through the gap in the radial direction of the coil,
A housing that houses the core, the stator, and the rotor,
The housing is provided with end plates provided at both ends of the rotor in the axial direction and supporting the rotor via bearings.
On the inner wall surface of the end plate, a protruding portion protruding in the axial direction is formed.
The bobbin has a partition wall that separates the coil and the rotor on a surface facing the rotor.
The partition wall is held by the protrusion.
A slotless motor featuring. The slotless motor according to claim 1.
The distance h1 to the tip of the protrusion and the distance h2 to the tip of the coil facing the protrusion with reference to the base end of the protrusion are configured such that h1> h2.
A slotless motor featuring. The slotless motor according to claim 1.
The coil shall be composed of distributed windings,
A slotless motor featuring. The slotless motor according to claim 1.
The partition wall is a slotless type motor characterized in that the partition wall and the projecting portion are held by the projecting portion by being fitted in an uneven manner. The slotless motor according to claim 1.
The protrusion is a slotless motor characterized by having a contact surface with which the partition wall abuts in the axial direction. The slotless motor according to claim 1.
The slotless type motor is characterized in that the protruding portion has a chamfered portion formed of an inclined surface that is inclined in a direction away from the partition wall toward the tip of the protruding portion with respect to the axial direction. With an annular core,
A stator with a cylindrical coil wound around a bobbin and placed adjacent to the core in the radial direction.
With the rotor arranged through the gap in the radial direction of the coil,
A housing that houses the core, the stator, and the rotor,
End plates provided at both ends of the housing in the axial direction of the rotor and supporting the rotor via bearings, and
An impeller directly connected to the rotating shaft of the rotor is provided.
On the inner wall surface of the end plate, a protruding portion protruding in the axial direction is formed.
The bobbin has a partition wall that separates the coil and the rotor on a surface facing the rotor.
The partition wall is held by the protrusion.
An electric blower featuring. The electric blower according to claim 7.
The distance h1 to the tip of the protrusion and the distance h2 to the tip of the coil facing the protrusion with reference to the base end of the protrusion are configured such that h1> h2.
An electric blower featuring. The electric blower according to claim 7.
The coil shall be composed of distributed windings,
An electric blower featuring. The electric blower according to claim 7.
The end plate is made of a material having a higher thermal conductivity than the housing.
An electric blower featuring. The electric blower according to claim 10.
The end plate was provided with an opening communicating with the stator arrangement area formed by the housing and the partition wall.
An electric blower featuring. The electric blower according to claim 7.
The housing is formed with a first flow path through which the airflow generated by the impeller passes.
A communication port that communicates the first flow path with the housing and the stator arrangement area formed by the partition wall, and an opening provided in the end plate on the side where the impeller is not provided. With
A second flow path is formed from the communication port to the opening.
An electric blower featuring. The electric blower according to claim 7.
The housing is formed with a first flow path through which the airflow generated by the impeller passes.
Each end plate has an opening that communicates with the stator placement area formed by the housing and the bulkhead.
A second flow path is formed from one of the openings to the other.
An electric blower featuring. A vacuum cleaner comprising the electric blower according to any one of claims 7 to 13.

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