TW201334370A - Permanent magnet motor and washing machine - Google Patents

Abstract

A permanent magnet motor is provided with a stator having a stator core wound by a stator coil and a rotor having substantially rectangular block-like permanent magnets which are arranged opposite the stator core in a frame and form a plurality of magnetic poles with alternately different polarities. The permanent magnets forming the plurality of magnetic poles are arranged such that the longitudinal direction is positioned in the circumferential direction of the stator core and the width direction is positioned in the radial direction of the stator core, and both ends in the thickness direction are set to have a thickness that projects from both ends of the stator core in the thickness direction. The permanent magnets forming the plurality of magnetic poles are made of a sintered body of magnetic powder and are oriented such that the magnetic flux flows circumferentially on the reverse side from the stator core side and radially on the stator core side in the longitudinal direction side, while the magnetic flux flows in the thickness direction on the reverse side from the stator core side and in the radial direction on the stator core side in the thickness direction side.

Description

Permanent magnet motor and washing machine

In the present embodiment, the rotor includes a permanent magnet motor including a plurality of permanent magnets as magnetic poles, and a washing machine including the permanent magnet motor.

For example, in a drum type washing machine, a permanent magnet motor is used as a motor that rotationally drives a drum that supports a washing machine. In the case where the permanent magnet motor is an outer rotor type in which the rotor is located outside the stator, the frame system constituting the rotor is formed into a flat, closed cylindrical container shape by a magnetic body such as an iron plate, and the inner peripheral side portion thereof is formed to be located. Outside the surrounding part of the stator. A plurality of (a plurality of) permanent magnets are arranged on the inner peripheral surface of the inner peripheral side portion on the stator side of the casing. The permanent magnet is formed in a substantially rectangular shape, and is a general permanent magnet in which a magnetic flux flows in a straight line in the width direction (diameter of the stator), in particular, in order to make the magnetic flux from the permanent magnet a sine wave, The surface on the stator side of the permanent magnet is formed in an arc shape in which the center protrudes toward the stator side. The frame must have a sufficient thickness as the back yoke to sufficiently recirculate the magnetic flux flowing from the stator side to the counter stator side of one permanent magnet.

However, when the magnetic force of the permanent magnet is large, the thickness of the casing is too large and the processing is difficult. Therefore, the ring is added to the counter-stator, that is, the circumferential side portion of the casing as a back yoke, so that the thickness of the casing is large and moderate. This portion is replenished with a ring to allow the magnetic flux to sufficiently reflow.

In this case, the ring and the permanent magnet must be magnetic and mechanical together. Since it is strongly bonded to the frame, a mold layer of a synthetic resin is applied from the portion adjacent to each of the permanent magnets to the outer periphery of the ring, and the permanent magnet and the ring are fixed to the peripheral side portion of the frame.

In the above configuration, particularly in the case where the magnetic force of the permanent magnet is large, in order to sufficiently recirculate the magnetic flux flowing through the permanent magnet, the frame body needs a large thickness and requires a ring, and further, a mold layer of a synthetic resin is also required. Larger volume. As a result, the overall size is increased, the weight thereof is increased, the inertia torque is increased, and the like, and the motor characteristics are relatively deteriorated and the cost is also increased.

Therefore, a permanent magnet motor has recently been conceived, which is provided with a permanent magnet as a rotor, and the permanent magnet is composed of a sintered body in which magnetic flux is distributed to a magnetic powder which is extremely heterogeneous, and a plurality of the permanent magnets are used. The permanent magnet motor is configured by arranging the polarities alternately on the stator side of the casing made of a magnetic material. According to this configuration, since the flow of the magnetic flux of the permanent magnet is aligned to the opposite side and the polarities are alternately arranged alternately, most of the magnetic flux flowing through one permanent magnet flows to the adjacent permanent magnet to sufficiently reflow. The amount of reflux flowing through the frame is reduced. Therefore, the frame does not need to be the thickness of the back yoke, nor does it need to be a ring of the back yoke. Further, the mold layer of the synthetic resin is also required to be reduced in volume, and as a result, the overall size can be reduced, the weight thereof can be reduced, and the cost can be reduced.

In addition, in recent years, for example, the popularity of electric vehicles and the like has increased, and the demand for permanent magnet motors has increased. It is desired to develop a permanent magnet capable of generating a larger magnetic force (in other words, a torque), and it is possible to achieve miniaturization, weight reduction, and cost reduction. Permanent magnet motor.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-299282

Therefore, a permanent magnet motor capable of achieving miniaturization, weight reduction, and low cost and high torque is provided, and a washing machine using the permanent magnet motor.

The permanent magnet motor according to the present embodiment includes a stator in which a stator core is wound around a stator coil, and a rotor in which a permanent magnet having a substantially rectangular block shape is arranged on a side corresponding to the stator core of the casing. a plurality of magnetic poles having mutually different polarities; the permanent magnets constituting the plurality of magnetic poles are disposed such that a longitudinal direction thereof is located on a circumferential side of the stator core, and a width direction is located on a radial direction side of the stator core, and The thickness dimension is set so that both end portions in the thickness direction protrude from both end portions in the thickness direction of the stator core, and the permanent magnets constituting the plurality of magnetic poles are composed of a sintered body of magnetic powder, and are aligned in the longitudinal direction. On the side, the magnetic flux flows in the circumferential direction on the opposite stator core side and flows in the radial direction on the stator core side; on the thickness direction side, the magnetic flux flows in the thickness direction on the opposite stator core side and flows in the radial direction on the stator core side. .

The washing machine of the embodiment is characterized in that the washing machine load is rotationally driven by the permanent magnet motor described above.

(one embodiment)

Hereinafter, an embodiment applicable to a drum type washing machine will be described with reference to the drawings.

First, in Fig. 6, a water tank 2 is disposed in the outer casing 1 of the washing machine. The water tank 2 is formed into a substantially cylindrical shape in which the front surface portion 2a (the right end surface portion of FIG. 6(a)) is closed as one end portion, and is substantially horizontal in the axial direction, and is damped by a damper mechanism (not shown). Supported elastically. A freely rotatable drum 3 constituting a rotary groove is disposed in the water tank 2. The drum 3 is also formed into a substantially cylindrical shape in which the front surface portion 3a (the right end surface portion of FIG. 6(a)) is closed as one end portion, and is disposed in a state in which the axial direction is substantially horizontal. A plurality of holes (not shown) are formed in the peripheral wall of the drum 3. Further, although not shown, the front portion 1a of the outer casing 1 is provided with a weir for opening and closing the entrance and exit of the laundry, and the front side of the water tank 2 and the drum 3 is formed with an opening, and the laundry is placed on the drum 3 via the entrance and exit of the laundry. In and out.

A permanent magnet motor 4 (hereinafter simply referred to as a motor 4) for rotationally driving the drum 3 is disposed on the back surface of the rear portion 2a of the water tank 2. In this case, the motor 4 is constituted by an external rotor type brushless DC motor, and the shaft 6 to which the rotor 5 is coupled is coupled to the rear portion of the drum 3. Thus, a direct drive mode in which the drum 3 is directly driven by the motor 4 is formed. The drum 3 corresponds to a washing machine load that is rotationally driven by the motor 4.

The motor 4 will be described with reference to Figs. 1 to 5 .

The stator 7 of the motor 4 is configured to have a plurality of teeth on the outer peripheral portion. The stator core 9 of the portion 8, the stator coil 10 wound around each tooth portion 8, and the mounting portion 11 made of synthetic resin are attached to the rear portion 2a of the water tank 2 in a fixed state through the mounting portion 11. The number of the teeth portions 8 is, for example, 36.

The structure of the rotor 5 includes a frame body 12 having a shallow bottom container shape having an annular wall 12a in the outer peripheral portion, and a plurality of (majority) 48 permanent magnets disposed on the inner peripheral portion of the annular wall 12a. 14 and 15; and a molding resin layer 13 (see FIGS. 1 and 3) in which the permanent magnets 14 and 15 are fixed to the annular wall 12a, and the shaft 6 is coupled to a central portion of the casing 12. Shaft mounting portion 16.

The permanent magnet 14 and the permanent magnet 15 are arranged such that the stator 7 side of the permanent magnet 14 (the tooth portion 8 side of the stator core 9) is an N pole for forming an N pole, and the stator of the permanent magnet 15 is formed. The 7 side is used to form the S pole of the S pole. The permanent magnets 14 and 15 are formed in a substantially rectangular block shape, and the circumferential direction of the frame body 12 (stator core 9) is the longitudinal direction, and the radial direction is the width direction. Further, as shown in FIGS. 4 and 5, the thickness Lm of the permanent magnets 14 and 15 is set to be larger than the thickness Ls of the stator core 9 of the stator 7, and both end portions in the thickness direction are formed to be thicker than the thickness of the stator core 9. Both ends of the direction also protrude. That is, the permanent magnets 14 and 15 form an overlapping state with respect to the stator core 9. Further, as shown in Fig. 1(a), the surface of the permanent magnet 14 corresponding to the stator core 9 side of the stator 7 (the surface on the N pole side) is formed as a central depression along the outer circumference of the stator 7 (stator core 9). The arcuate surface 14a is formed in an arc shape, and the corner portions of both end portions in the longitudinal direction are cut away to form a notch portion 14b. Similarly, as shown in FIG. 1(a), the permanent magnet 15 The surface (the surface on the S pole side) of the stator 7 on the side of the stator core 9 is formed in an arc shape which is recessed in the center along the outer circumference of the stator 7 (stator core 9) to form a circular arc surface 15a, and its longitudinal direction The corner portions of both end portions are cut away to form a notch portion 15b.

The permanent magnets 14 and 15 constituting the plurality of magnetic poles are composed of a neodymium magnet or a ferrite magnet made of sintered magnetic powder, and the magnetic flux The flow direction is aligned to the extreme side, on the longitudinal side and the thickness direction side, and is concentrated in the center of the stator core 9 of the stator 7. That is, as shown in Fig. 1(a), the magnetic flux is on the longitudinal side of the permanent magnet 14 for the N pole. It is arranged to flow in the circumferential direction from both ends of the annular wall 12a side (inverse stator core 9 side), and flows in the radial direction toward the center of the stator 7 side (the stator core 9 side); the permanent magnet for the S pole Length side of 15, flux The alignment is performed in the radial direction from the center of the stator 7 side (the stator core 9 side), and flows in the circumferential direction toward both ends of the annular wall 12a side (the reverse stator core 9 side). Thereby, as shown in FIG. 1(b), the magnetic flux distributions of the surfaces of the permanent magnets 14 and 15 corresponding to the stator core 9 side of the stator 7 are all formed in a sinusoidal shape.

Further, as shown in Fig. 4 (a), the magnetic flux is on the thickness direction side of the permanent magnet 14 for the N pole. The flow direction flows in the thickness direction from both ends in the thickness direction from the side of the annular wall 12a (see FIG. 2) (on the side of the counter stator core 9), and flows in the radial direction toward the center of the stator core 9 side of the stator 7; As shown in Fig. 5(a), the magnetic flux is on the thickness direction side of the permanent magnet 15 for the S pole. The flow direction flows in the radial direction from the center of the stator core 9 side of the stator 7, and flows in the thickness direction toward both ends in the thickness direction of the annular wall 12a (see FIG. 2) side (the reverse stator core 9 side). As a result, as shown in FIGS. 4(b) and 5(b), the magnetic flux distributions of the permanent magnets 14 and 15 corresponding to the surface on the stator core 9 side are all formed in a sinusoidal shape.

Further, the alignment and sintering of the permanent magnets 14 and 15 formed by sintering the magnetic powder are, for example, placing the magnetic powder and water in a chamber in the mold in a free state, and in this state, the magnetic flux The magnetic field is supplied as described above, and the magnetic powder is pressed as the water in the chamber is discharged, and then sintered.

Although not shown, the motor 4 is formed to be controlled by a frequency conversion circuit by a control device including a microcomputer. The control device has a function of performing control of a washing operation to be described later.

The role of the above configuration will be explained.

When the control device starts the washing operation, the water supply stroke is first performed. In the water supply stroke, the water supply valve (not shown) is opened to supply water into the water tank 2, and then supplied to the drum 3 and stored. Next, a washing course is performed. In the washing course, the drum 3 is rotated in the reverse direction by the motor 4 at a low rotation speed of 50 to 60 rpm, for example, in a state where the washing agent is put into the water tank 2. Thereby, the laundry stored in the drum 3 is washed. After the washing course is performed for a predetermined period of time, the draining stroke is performed. In the draining stroke, the water in the water tank 2 (in the drum 3) is discharged to the outside of the machine by opening a drain valve (not shown) connected to the discharge port of the water tank 2 while the drum 3 is stopped.

Next, the water supply stroke is again performed, water is supplied into the water tank 2, and then water is supplied into the drum 3 and stored. Next, a cleaning stroke is performed. In the cleaning process, the same as the washing course except that the lotion is not used. control. That is, the drum 3 is rotated in the reverse direction by the motor 4 at a low rotation speed of 50 to 60 rpm, for example, thereby washing the laundry in the drum 3. Then, the same drainage stroke as described above is performed.

Next, a dehydration process is performed. The dehydration stroke is rotated by the motor 4 in a single direction, for example, at a high speed of 1000 rpm. Thereby, the washings in the drum 3 are centrifugally dehydrated. The washing operation is ended by the above method.

According to this embodiment, the thickness Lm of the permanent magnets 14 and 15 is set larger than the thickness Ls of the stator core 9 of the stator 7, and both end portions in the thickness direction are formed at both ends in the thickness direction of the stator core 9. The part is also prominent, and the magnetic flux of the permanent magnets 14 and 15 The flow direction is aligned to the opposite side, and is concentrated on the longitudinal direction side and the thickness direction side and concentrated on the center of the stator 7 side (the stator core 9 side), so that the magnetic flux distribution acting on the tooth portion 8 of the stator 7 forms a sine wave shape. The formation of a stronger magnetic force can produce a high torque, and is suitable as a motor 4 that performs a cleaning and cleaning stroke requiring a low speed and a high torque.

Moreover, since the permanent magnets 14 and 15 are arranged alternately in polarity, the magnetic flux flowing through one permanent magnet Most of them flow to the adjacent permanent magnets and are sufficiently recirculated, and the amount of reflow flowing through the frame 12 is reduced. Therefore, the frame 12 does not need to be the thickness of the back yoke, nor does it need to be a ring of the back yoke. Further, the mold layer 13 of the synthetic resin is also small in size, and as a result, the motor 4 can be made smaller, lighter, lower in cost, and high in torque.

Also, due to the stator cores of the permanent magnets 14 and 15 corresponding to the stator 7 The face 9 is formed along the arcuate faces 14a and 15a of the stator core 9, so that the air gap with the stator 7 can be minimized, and the magnetic force acts on the stator coil 10 with good efficiency, and The volume of the rotor 5 is minimized. Further, by forming the surfaces of the permanent magnets 14 and 15 corresponding to the stator core 9 into the circular arc surfaces 14a and 15a, the air resistance during the rotation of the rotor 5 can be reduced, and noise caused by turbulence can be prevented. Further, since the notch portions 14b and 15b are formed by cutting the corner portions of both end portions of the circular arc faces 14a and 15a of the permanent magnets 14 and 15, it is possible to prevent the magnetic characteristics of the corner portion from being demagnetized.

(Other embodiments)

The motor 4 is not limited to the outer rotor type, and may be an inner rotor type.

As the washing machine, a washing and drying machine having a drying function can also be used.

The washing machine is not limited to the drum type washing machine, and a vertical axis type washing machine in which the rotary groove is oriented in the vertical direction may be used. In such a washing machine, the permanent magnet motor is in the washing stroke and the washing stroke, and the stirring body for stirring the washing material is rotated forward and backward at a low speed, and the stirring body and the rotating tank are integrally rotated at a high speed in one direction in the dehydrating stroke. . In this case, the washing machine load that is rotationally driven by the permanent magnet motor is a stirring body and a rotating tank.

According to the embodiment, the permanent magnet motor includes a stator in which the stator core is wound around the stator coil, and a rotor in which the permanent magnets of the frame body are arranged in a substantially rectangular block shape on the side corresponding to the stator core. Forming, the permanent magnet constitutes a plurality of magnetic poles having mutually different polarities; characteristics thereof The permanent magnets constituting the plurality of magnetic poles are disposed such that the longitudinal direction thereof is located on the circumferential side of the stator core, the width direction is located on the radial direction side of the stator core, and the thickness dimension is set to be greater than the thickness direction. Both ends of the stator core in the thickness direction protrude; the permanent magnets constituting the plurality of magnetic poles are formed of a sintered body of magnetic powder, and are aligned such that the magnetic flux is on the side of the counter stator core in the longitudinal direction side. The direction flows and flows in the radial direction on the stator core side; on the thickness direction side, the magnetic flux flows in the thickness direction on the opposite stator core side and flows in the radial direction on the stator core side. According to this configuration, it is possible to achieve miniaturization, weight reduction, cost reduction, and high torque as a permanent magnet motor.

Although a few embodiments have been described above, these embodiments are intended to be illustrative and not intended to limit the scope of the invention. The present invention can be implemented in various other forms, and various omissions, substitutions and changes can be made without departing from the scope of the invention. The invention and its modifications are intended to be included within the scope of the invention and the scope of the invention.

1‧‧‧Shell

3‧‧‧Roller (washing machine load)

4‧‧‧ permanent magnet motor

5‧‧‧Rotor

7‧‧‧ Stator

8‧‧‧ teeth

9‧‧‧Silker core

10‧‧‧statar coil

13‧‧‧Molding layer

14‧‧‧ permanent magnet for N pole

Permanent magnet for 15‧‧‧S

Fig. 1 shows an embodiment, (a) is a partially enlarged cross-sectional view of a stator and a rotor, and (b) is a magnetic gas characteristic diagram of a permanent magnet.

2 is a perspective view of a permanent magnet motor.

Fig. 3 is a partially enlarged perspective view of the stator and the rotor.

Fig. 4(a) is a schematic view showing the arrangement relationship of the permanent magnets for the stator and the N pole in the thickness direction, and (b) the magnetic characteristics of the N pole permanent magnets. Figure.

Fig. 5(a) is a schematic view showing the arrangement relationship of the permanent magnets for the stator and the S pole in the thickness direction, and Fig. 5(b) is a magnetic gas characteristic diagram of the permanent magnet for the S pole.

Fig. 6 is a view showing a schematic configuration of a drum type washing machine, wherein (a) is a longitudinal side view and (b) is a longitudinal rear view.

12a‧‧‧ annular wall

14‧‧‧ permanent magnet for N pole

‧‧‧Magnetic

Permanent magnet for 15‧‧‧S

5‧‧‧Rotor

13‧‧‧Molding layer

15b‧‧‧Gap section

8‧‧‧ teeth

7‧‧‧ Stator

15a‧‧‧Arc face

14b‧‧‧Gap section

14a‧‧‧Arc surface

9‧‧‧Silker core

Claims (5)

A permanent magnet motor comprising: a stator formed by winding a stator coil around a stator core; and a rotor formed by arranging a substantially rectangular block-shaped permanent magnet on a side of the frame corresponding to the stator core, the permanent magnet forming a polarity a plurality of magnetic poles that are alternately different; wherein the permanent magnets constituting the plurality of magnetic poles are disposed such that a longitudinal direction thereof is located on a circumferential side of the stator core, and a width direction is located on a radial direction side of the stator core, and a thickness dimension Both end portions in the thickness direction are protruded from both end portions in the thickness direction of the stator core, and the permanent magnets constituting the plurality of magnetic poles are composed of a sintered body of magnetic powder, and are aligned on the longitudinal direction side. The magnetic flux flows in the circumferential direction on the counter stator core side and flows in the radial direction on the stator core side. On the thickness direction side, the magnetic flux flows in the thickness direction on the counter stator core side and flows in the radial direction on the stator core side. The permanent magnet motor of claim 1, wherein the surface of the stator core side of the permanent magnet is formed in an arc shape along the stator core. A permanent magnet motor according to claim 1, wherein a corner portion of both ends in the longitudinal direction of the side of the permanent magnet corresponding to the stator core is cut away. The permanent magnet motor according to claim 2, wherein a corner portion of both ends in the longitudinal direction of the side of the permanent magnet corresponding to the stator core is cut away. A washing machine characterized by being configured to rotationally drive a washing machine load by a permanent magnet motor according to any one of claims 1 to 4.