JP2013009542A - Drum washing machine using magnet motor - Google Patents

Abstract

Provided is a drum type washing machine that employs a magnet motor capable of ensuring necessary torque characteristics even when a ferrite magnet having a weak coercive force is used and preventing demagnetization of the ferrite magnet.
In a drum-type washing machine in which a magnet motor for driving a rotating drum is operated in a field weakening operation during dehydration operation, the magnet motor includes a rotor and a stator, and the rotor forms a permanent magnet that forms a magnetic pole. The stator has a plurality of slots formed in the stator core and teeth around which concentrated armature windings are wound, and the width of the teeth is set on the inner diameter side. The outer diameter side was made wider.
[Selection] Figure 3

Description

  The present invention relates to a magnet motor and relates to a drum type washing machine using the same.

  In current drum-type washing machines, a method (direct drive method) in which a magnet motor is directly connected to a rotating shaft of a rotating drum is driven (direct drive method). Usually, in a drum-type washing machine, since it is necessary to drive a rotating drum at a low speed and a high torque in a washing process, a neodymium magnet is adopted as a magnet. Since neodymium, which is the main raw material of this neodymium magnet, is a rare metal and may be difficult to obtain, it has recently been screamed to use a rare metal, that is, a ferrite magnet. However, while the residual magnetic flux density of the neodymium magnet is 1.3T, the residual magnetic flux density of the ferrite magnet is as small as 0.45T (about 1/3), and there is a problem that the physique is increased in the ferrite magnet motor.

  As a technique for avoiding the above problem, it is shown that flat ferrite magnets are arranged radially because the amount of magnetic flux from the magnet depends on the circumference of the ferromagnetic surface of the magnet (Patent Document 1, Patent Document 1). Non-patent document 1).

JP 2006-20425 A

Denki Shoin: Alternator design: PP559-564

  In the case of the techniques of Patent Document 1 and Non-Patent Document 1, since the ferrite magnets that extend radially with respect to the outer diameter of the rotor are long, the required torque characteristics can be obtained even if a ferrite magnet is used.

  On the other hand, there are a washing process and a dehydrating process as an operation method of the drum type washing machine. The rotating drum needs to be driven to a high speed region with a low speed and a high torque in the washing process and with a low torque in the dehydration process. In this dehydration process, the magnet motor is operated in a weak field, so there is a problem that a ferrite magnet having a weak coercive force demagnetizes.

  The present invention has been made in order to solve the above problem, and a drum employing a magnet motor that can secure necessary torque characteristics and prevent demagnetization of the ferrite magnet even when a ferrite magnet having a weak coercive force is used. An object is to provide a washing machine.

  In order to achieve the above object, in the present invention, in a drum type washing machine in which a magnet motor for driving a rotating drum is operated in a field weakening mode during dehydration operation, the magnet motor includes a rotor and a stator, and the rotor is The stator is configured by radially arranging permanent magnets, and the stator has a plurality of slots formed in the stator core and teeth around which concentrated armature windings are wound, The width of the teeth is wider on the outer diameter side than on the inner diameter side.

  According to the above configuration, since the width of the teeth around which the armature winding is wound is wider on the outer diameter side than on the inner diameter side, the d-axis reactance and the q-axis reactance of the armature winding are increased. As a result, even if the current is small, the vector sum of the reactance voltages acts in the direction of decreasing the terminal voltage of the magnet motor, and the demagnetization of the ferrite magnet can be prevented.

It is a general-view figure of the drum type washing machine concerning one embodiment of the present invention. It is an axial sectional view of a magnet motor concerning one embodiment of the present invention. 3 is a radial cross section of the magnet motor of FIG. 2. It is the figure which expanded the principal part A of FIG. 3 is a radial cross section of a rotor portion of the magnet motor of FIG. 2. FIG. 6 is an axial sectional view of the rotor portion of FIG. 5. FIG. 3 is a view showing a state in which magnetic pole cores and permanent magnets of the magnet motor of FIG. 2 are alternately arranged to form an annular shape. It is the figure which expanded the principal part A of FIG.

  Hereinafter, a drum type washing machine 100 according to an embodiment of the present invention and a magnet motor 1 used therefor will be described with reference to FIGS.

  FIG. 1 is an overview of a drum type washing machine 100 according to the present embodiment.

  The drum-type washing machine 100 includes a housing 101 having an open front panel and a housing base 102 having rubber legs at four corners, and is attached to the opening of the housing 101 so that the door 103 can be opened and closed. It has been. Moreover, the housing | casing 101 is provided with the outer tank 105 which includes the rotating drum 104 as an inner tank. A magnet motor (not shown) that rotationally drives the rotary drum 104 is attached to this back surface. Then, a washing process, a rinsing process, a dehydrating process, and the like are executed by the rotation of the rotating drum 104.

  2 is an axial sectional view of the magnet motor according to the present invention, FIG. 3 is a radial sectional view of the magnet motor of FIG. 2, FIG. 4 is an enlarged view of the main part A of FIG. 3, and FIG. 6 is a sectional view in the radial direction of the rotor portion of the motor, FIG. 6 is an axial sectional view of the rotor portion in FIG. 5, and FIG. 7 is formed in an annular shape by alternately arranging the magnetic core and permanent magnet of the magnet motor in FIG. FIG. 8 is an enlarged view of the main part A of FIG.

  As shown in FIG. 2, the magnet motor 1 includes a stator 10, a stator base portion 20, a rotor 30, a bearing boss 21 having a bearing, and a bearing 30 that is rotatably supported by the bearing and fixes and supports the rotor 30. It is comprised with the rotating shaft 22. FIG. The stator 10 is fixed to the stator base portion 20 by fastening bolts 27, and the rotor 30 is fitted to a boss portion 23 provided at the end of the rotating shaft 22, and is fixed by a screw portion 24 and a nut 25. Has been. Bearings 26 (26 a, 26 b) are arranged on the inner peripheral side of the stator base portion 20 and the outer peripheral side of the rotating shaft 22, and are supported so that the rotor 30 can rotate freely on the inner peripheral side of the stator 10. Has been.

  Further, as shown in FIG. 3, the stator 10 is a stator core 13 composed of a core back 11 and a tooth 12 (the core back 11 and the tooth 12 are bent from a linear shape and formed into an arc shape. Is configured to fit in the housing 18. Then, armature windings (stator coils) 15 that are three-phase windings (concentrated windings) are wound in a plurality of slots 14 formed in the stator core 13. Here, the width of the teeth 12 of the stator core 13 is wider on the outer diameter side than on the inner diameter side of the slot 14. Further, as shown in FIG. 4, the shape of the inner peripheral surface of the teeth 12 constituting the fixed magnetic pole is a convex non-concentric shape 17 on the rotor 30 side, and beveling 16 is applied to the end of the teeth 12. Yes. As described above, since the width of the tooth 12 is wider on the outer diameter side than the inner diameter side of the slot 14, both the shape of the tooth 12 and the shape of the slot 14 form an inverted trapezoidal shape.

  As described above, by making the width of the tooth 12 around which the armature winding 15 is wound wider on the outer diameter side than on the inner diameter side of the slot 14, the following effects can be obtained.

  Generally, in the magnet motor 1, since the magnetic flux of the magnet is constant, the counter electromotive force generated by the magnetic flux increases as the rotational speed of the magnet motor 1 increases. When a certain number of revolutions is reached, the counter electromotive force becomes the same as the applied voltage of the magnet motor 1, and the number of revolutions cannot be increased further. The field weakening compensates for this, and the counter electromotive force can be reduced by advancing the phase of the current flowing through the armature winding 15 (in the direction of weakening the magnetic flux of the magnet). It becomes possible to drive 1 to high speed.

  However, if current is supplied in a direction that weakens the magnetic flux of the magnet, the magnet may be demagnetized. Therefore, in the present embodiment, the width of the tooth 12 around which the armature winding 15 is wound is made wider on the outer diameter side than the inner diameter side of the slot 14, so that the d-axis reactance and q of the armature winding 15 are increased. Axial reactance can be increased. Here, the vector sum of the reactance voltages acts in the direction of decreasing the terminal voltage of the magnet motor 1. Therefore, with this configuration, field weakening can be achieved even with a small current, and as a result, demagnetization of the ferrite magnet can be prevented.

  Further, by applying the beveling 16 to the end portion of the tooth 12, it is possible to suppress a sudden change in magnetic flux due to the armature winding 15 and further prevent demagnetization of the ferrite magnet.

  On the other hand, the rotor 30 has the rotor core 31 which laminated | stacked the electromagnetic steel plate, and the permanent magnet piece 32 as shown in FIG. The rotor core 31 faces the inner surface of the tooth 12 and rotates so as to move relative to the tooth 12. Further, the permanent magnet piece 32 uses ferrite as a magnet element, and realizes thinness, light weight and high torque. Then, the permanent magnet piece 32 is sandwiched between the rotor cores 31 to form an annular shape, and then molded with the synthetic resin layer 70. Further, the boss portion 23 is also molded with the synthetic resin layer 33 to integrate the rotor 30. Here, the outer peripheral shape of the rotor core 31 is a non-concentric shape that is convex toward the stator 10 side.

  Next, the rotor 30 will be described in detail. As shown in FIGS. 3 to 6, the rotor 30 is a primary molded body in which a large number of divided rotor cores 31 and permanent magnet pieces 32 are fixed integrally with a resin material (synthetic resin layer) 70. The primary mold body and the shaft connecting member are integrally fixed with a resin material (synthetic resin layer) 33 to form a secondary mold body.

  As shown in FIG. 3, the rotor cores 31 and the permanent magnet pieces 32 are alternately arranged in a radial pattern so as to form a cylindrical shape. Here, the non-magnetized magnet element is used for the permanent magnet piece 32 and is magnetized after forming the primary mold body of the rotor 30 as will be described later. That is, when the permanent magnet piece 32 is assembled, the permanent magnet piece 32 is not magnetized, so that there is no confirmation leakage or wrong insertion of the magnetization direction of the permanent magnet piece 32, and the permanent magnet piece 32 remains in the wrong magnetization direction. There is no fear of being incorporated.

  As shown in FIG. 8, a hole 50 is provided in the central portion of the rotor core 31. The holes 50 are filled with a resin material 70 for primary molding and fused. In addition, a gap is formed between the adjacent rotor cores 31 on the inner diameter side and the outer diameter side of the permanent magnet piece 32. That is, each permanent magnet piece 32 has a structure in which both side surfaces on the inner diameter side and the outer diameter side do not contact the rotor cores 31, 31. These gaps act so as to reduce the leakage magnetic flux of the permanent magnet piece 32, and act on the magnetizing described later so that the magnetic flux is efficiently taken into the permanent magnet piece 32. In addition, these voids are filled and fused with the resin material 70 for primary molding in the same manner as described above. That is, the permanent magnet piece 32 is sandwiched between the rotor cores 31 and 31 from both sides in the rotational direction, and is also supported by the rotor cores 31 and 31 via the resin material 70 in the radial direction.

  Further, as shown in FIG. 8, a keyhole-shaped recess 60 is formed on the inner surface which is the inner diameter side of the rotor core 31. The recess 60 is filled with a resin material 33 for secondary molding and fused. Thereby, even at the time of high speed rotation of the rotor 30, the connection strength between the rotor core 31 and the permanent magnet piece 32 can be maintained, and a strong fixing structure that resists centrifugal force can be obtained.

  Further, a boss portion 23 as a shaft connecting member is provided inside the rotor 30. The boss portion 23 is covered with a resin material 33 for secondary molding and is integrally fixed to the rotor 30.

  Next, a method for manufacturing the magnet motor 1 having such a rotor 30 will be described. First, as shown in FIG. 7, the rotor cores 31 and the permanent magnet pieces 32 are alternately arranged radially to form an assembly 40 of the rotor core 31 and the permanent magnet pieces 32 having an annular shape. . At this time, after all the rotary iron cores 31 are arranged on a jig or the like (not shown), the permanent magnet pieces 32 are inserted between the rotor iron cores 31 to obtain an assembly 40 in which these are alternately arranged. Since the permanent magnet piece 32 is not magnetized, it can be smoothly inserted between the rotor cores 31 and 31.

  Next, it arrange | positions to the shaping | molding die for molds in the state of the assembly | attachment body 40, and pours the resin material 70 for primary molds. As a result, a primary mold body integrally fixed with the resin material 70 is obtained. Thereafter, the boss portion 23 and the like are arranged on the inner side of the primary mold body magnetized by magnetizing the permanent magnet piece 32, and then the resin material 33 for the secondary mold is poured. As a result, as shown in FIG. 3, a secondary mold body is obtained in which these are integrally fixed by the resin material 33 for secondary molding, and the rotor 30 is formed. Furthermore, as shown in FIG. 2, the magnet motor 1 is obtained by arranging the rotor 30 on the inner diameter side of the stator fixed to the stator base portion 20 and fixing the rotor 30 to the rotating shaft 22.

DESCRIPTION OF SYMBOLS 1 Magnet motor 10 Stator 11 Core back 12 Teeth 13 Stator iron core 14 Slot 15 Armature winding 16 Beveling 17 Non-concentric shape 18 Housing 20 Stator base part 21 Bearing boss 22 Rotating shaft 23 Boss part 24 Thread part 25 Nut 26 Bearing 30 Rotor 31 Rotor core 32 Permanent magnet piece 40 Assembly 100 Drum-type washing machine 101 Housing 102 Housing base 103 Door 104 Rotating drum 105 Outer tub

Claims (4)

  In a drum-type washing machine in which a magnet motor that drives a rotating drum is operated in a weak field during dehydration operation, the magnet motor includes a rotor and a stator, and the rotor radially arranges permanent magnets that form magnetic poles. The stator has a plurality of slots formed in the stator core and teeth on which concentrated winding armature windings are wound, and the width of the teeth is set on the outer diameter side from the inner diameter side. A drum-type washing machine characterized by having a wider side.   2. The drum type washing machine according to claim 1, wherein the slot and the teeth are both formed in an inverted trapezoidal shape.   2. The drum type washing machine according to claim 1, wherein the inner peripheral surface of the teeth has a non-concentric shape convex toward the rotor side, and beveling is applied to an end portion of the non-concentric shape.   2. The drum type washing machine according to claim 1, wherein a rotor core is disposed between the permanent magnets, and the permanent magnet and the rotor core are molded with resin.