JP5634338B2 - Magnet motor and drum type washing machine equipped with magnet motor - Google Patents

Description

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

  Since most washing machines are used at home, the demand for noise level during use is low at around 40 dB. To achieve this, the inner peripheral surface of the teeth in the stator and the outer periphery of the magnetic core in the rotor It has been shown that the surfaces adopt non-concentric shapes that are convex to each other (Patent Document 1 below).

  In particular, current drum-type washing machines are mainly driven by a system (direct drive system) in which a magnet motor is directly connected to a rotating shaft of a rotating drum. 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 this problem, it has been shown that flat ferrite magnets are arranged radially since the amount of magnetic flux from the magnet depends on the circumference of the ferromagnetic surface of the magnet (the following non-patent document) 1, the following patent document 2).

JP 2009-89546 A JP 2006-20425 A

Denki Shoin: Alternator design: PP559-564

  In the technology described in Patent Document 1, a rare earth permanent magnet is used as a rotor, and the inner peripheral surface of the rotor teeth and the outer peripheral surface of the magnetic pole core of the rotor are simply non-concentric with each other. Therefore, if a ferrite magnet having a low magnetic force is used, it is difficult to obtain necessary characteristics.

  Further, in the techniques described in Non-Patent Document 1 and Patent Document 2, since the radially extending magnet of the rotor is long in the radial direction, a decrease in torque characteristics can be suppressed even when a ferrite magnet is used. There was no consideration.

  The present invention has been made in view of the above, and an object of the present invention is to provide a magnet motor capable of reducing noise while securing characteristics even when a ferrite magnet is used.

In order to achieve the above object, according to the present invention, a magnet motor for driving a rotary drum has a rotor and a stator, and the stator includes a plurality of slots formed in the stator core, and a concentrated winding armature. comprising a tooth winding is wound, the rotor includes a permanent magnet to form a magnetic pole, the drum-type washing machine having a rotor core formed by laminating magnetic steel sheets, and the permanent magnet and the rotor core The teeth are arranged alternately to form a cylindrical shape, and the inner peripheral surface of the teeth has a non-concentric shape that protrudes toward the rotor, and beveling is applied to the circumferential end of the non-concentric shape. The outer peripheral surface of the rotor core has a non-concentric shape convex toward the stator, and ferrite is used for the permanent magnet .

  According to the said structure, the magnet motor which can aim at reduction of a noise can be provided, ensuring a characteristic even if it uses a ferrite magnet.

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. It is a figure which shows the noise measurement result of the drum type washing machine concerning one Embodiment of this invention.

  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. Further, as shown in FIG. 4, the inner peripheral surface shape of the teeth 12 constituting the fixed magnetic pole has a convex non-concentric shape 17 on the rotor 30 side, and beveling 16 is applied to the end portion of the teeth 12. .

  In FIG. 9, when a non-concentric shape 17 that is convex on the outer peripheral surface of the rotor core 31 and the inner peripheral surface of the tooth 12 is employed ((a) without beveling), the periphery of the non-concentric shape 17 is further increased. The measurement result of noise in the case where beveling is applied to the direction end ((b) with beveling) is shown. The horizontal axis represents frequency Hz, and the vertical axis represents noise dB (A). According to FIG. 9, it can be seen that particularly noise having a frequency component of 1905 Hz is extremely small in the case of beveling compared to the case of no beveling. That is, the noise reduction effect of 3 dB (A) can be confirmed by the overall noise value.

  Here, with respect to the inner peripheral surface of the tooth 12, it is possible to reduce noise by increasing the non-concentric shape 17, but in that case, the gap length between the stator 10 and the rotor 30 is large. Thus, the required torque is reduced. Therefore, by applying the beveling 16 as described above, it is decided to maintain the gap length and secure the characteristics as the magnet motor 1 while suppressing an increase in noise due to a sudden change in the magnetic flux of the magnet.

  Further, when the range for forming the beveling 16 was varied and measured, as shown in FIG. 4, the pitch of the teeth 12 was θ, the non-concentric angle of the teeth 12 (the inner peripheral surface of the teeth 12, Assuming that θ1 is the length of the area where the step R of the beveling 16 is not provided, it has been found that if 0.5 ≦ θ1 / θ ≦ 0.7, it contributes to noise reduction. In particular, when θ1 / θ is in the vicinity of 0.65, an extremely high effect was obtained.

  In addition, by applying the beveling 16 to the circumferential end portion of the inner peripheral surface of the tooth 12 in this way, it is possible to suppress a sudden change in magnetic flux due to the armature winding 15 and 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, since the outer peripheral surface shape of the rotor core 31 is a non-concentric shape convex toward the stator 10, the gap between the rotor 30 and the stator 10 can be reduced, and as a result, the magnet motor 1 These characteristics can be kept good.

  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 rotor cores 31 are arranged on a jig or the like (not shown), the permanent magnet pieces 32 are inserted between the rotor 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 body 40, and pours the resin material 70 for primary molding. 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 Screw 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 (3)

A magnet motor for driving a rotating drum has a rotor and a stator, and the stator includes a plurality of slots formed in the stator core, and teeth around which concentrated armature windings are wound, The rotor is a drum-type washing machine having a permanent magnet that forms magnetic poles and a rotor core in which electromagnetic steel plates are stacked, and the permanent magnet and the rotor core are alternately arranged radially to form a cylindrical shape. aligned to the inner peripheral surface of the teeth, the non-concentric convex to the rotor side, subjected to beveling the circumferential ends of the non-concentric shape, the outer peripheral surface of the rotor core, wherein A drum-type washing machine characterized by having a non-concentric shape convex on the stator side and using ferrite for the permanent magnet . 2. The drum type washing machine according to claim 1, wherein the rotor core and the permanent magnet are molded with resin . The drum type washing machine according to claim 1, wherein the pitch of the teeth is θ and the angle of the non-concentric shape of the teeth is θ1, and 0.5 ≦ θ1 / θ ≦ 0.7 .