JP2015080336A - Magnet motor and washing machine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet motor capable of improving the reliability by increasing fastening strength of lamination in a rotor core.SOLUTION: The magnet motor includes: a stator 10; and a rotor 30 which rotates relative to the stator. The rotor is formed in a ring-shape in which permanent magnet pieces 32 and rotor cores 31 are disposed alternately radially. In a magnet motor 1 having the rotor core which is constituted of laminated electromagnetic steel plates, each of the permanent magnets and rotor core are formed in an arc shape. Plural lamination fastening parts 52 are provided to the rotor core so that the distance to both ends of the rotor core is generally the same in a peripheral direction.

Description

  The present invention relates to a magnet motor, and more particularly to a washing machine using the same.

  The current drum-type washing and drying machine is mainly driven by a magnet motor directly connected to a rotating shaft of a washing tub (direct drive method, hereinafter referred to as DD method). Usually, in a drum-type washing and drying machine, it is necessary to drive the washing tub at a low speed and a high torque in the washing process, so a rare metal, that is, a neodymium magnet, was previously used as the magnet material. Recently, inexpensive ferrite magnets are used.

  However, the residual magnetic flux density of the neodymium magnet is 1.3T, whereas the residual magnetic flux density of the ferrite magnet is as low as 0.45T (about 1/3). It was necessary to arrange the magnets radially and to increase the amount of magnetic flux of the magnet by increasing the circumference of the permanent magnet.

  For example, in Patent Document 1 below, permanent magnet pieces are arranged radially, the magnetization direction of the permanent magnet is set to the circumferential direction, and the permanent magnet pieces and the rotor core are alternately arranged to form an annular shape. A brushless motor having a rotor is disclosed. Further, both end portions in the circumferential direction of the permanent magnet piece and the rotor core are linearly extended in the radial direction.

JP 2012-217269 A

  The laminated fastening locations of the laminated rotor cores are arranged on the central axis of the magnetic pole in consideration of magnetic balance. However, unlike the magnet motor disclosed in Patent Document 1 described above, the shapes of the permanent magnet pieces and the rotor core on both sides in the circumferential direction are not linear. There was a possibility that the distance from the circumferential side end of the core to the laminated fastening location would be short and the fastening strength would be insufficient. If the fastening strength is insufficient in this way, the laminate may be peeled off before molding the permanent magnet piece and the rotor core, or may be divided into a plurality of pieces by molding pressure and fixed as they are, and the performance of the motor is significantly reduced. Occurs.

  In view of the above-described problems, an object of the present invention is to provide a magnet motor in which the fastening strength of lamination of rotor cores is increased and the reliability is improved.

  In order to achieve the above object, the present invention comprises a stator and a rotor that rotates with respect to the stator, and the rotor has an annular shape in which permanent magnet pieces and a rotor core are alternately arranged radially. In the magnet motor in which the rotor core is configured by laminating electromagnetic steel plates, the permanent magnet and the rotor core are formed in a bow shape, and each lamination fastening portion of the rotor core is formed by the rotor. A plurality of iron cores were provided so that the distances between the both ends in the circumferential direction of the iron core were substantially the same.

  It is possible to provide a magnet motor with improved reliability by increasing the fastening strength of the laminated rotor cores.

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. It is an enlarged view of the principal part of the radial direction cross section of the magnet motor of FIG. It is the figure which showed the plane and front of the rotor of the magnet motor of FIG. It is a figure which shows the state which arranged the rotor core and the permanent magnet alternately, and formed in the annular | circular shape. It is the figure which showed the plane and front of a primary mold body. It is a figure which shows the state which has arrange | positioned the iron core support base | substrate and the boss | hub part in the primary mold body. It is the figure which showed each part dimension of the rotor core and the permanent magnet piece. It is a figure which shows the relationship between the internal-diameter side space | gap part dimension of a rotor core, a magnet thickness dimension, and an induced voltage constant. FIG. 10 is a diagram showing the relationship of FIG. 9 with the dimensional ratio W / T on the horizontal axis and the induced voltage constant (pu) on the vertical axis. It is the figure which expanded the stator iron core. It is the figure which showed the dimensional relationship about FIG.

  Hereinafter, a drum type washing machine 100 according to an embodiment of the present invention and a magnet motor 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 1 (not shown) for rotating the rotating drum 104 is attached to the 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.

  FIG. 2 is an axial sectional view of the magnet motor 1 according to the present embodiment. Here, in the portion where the stator 10 and the rotor 30 face each other, the upper A indicates a cross section including the permanent magnet piece 32, and the lower B indicates a cross section including the rotor core 31. ing. As shown in FIG. 2, the magnet motor 1 is rotatable on the stator 10, the stator base 20, the rotor 30, the bearings 26 (26 a and 26 b), the bearing boss portion 23, and the bearing 26. The rotary shaft 22 is supported and fixed to support the rotor 30. The stator 10 is fixed to the stator base portion 20 by fastening bolts 21, and the rotor 30 is fitted to a bearing boss portion 23 provided at an end portion of the rotating shaft 22, and a screw portion 24 and a nut 25. It is fixed by. Further, bearings 26 (26 a, 26 b) are disposed on the inner peripheral side of the stator base portion 20 and on the outer peripheral side of the rotating shaft 22, and the rotor 30 can rotate freely on the inner peripheral side of the stator 10. So that it is supported.

  FIG. 3 is a radial cross-sectional view of the magnet motor 1 in FIG. 2, and shows an enlarged portion where the stator 10 and the rotor 30 face each other. First, the stator 10 includes a stator core 13 having a core back 11 and teeth (fixed magnetic poles) 12 and a plurality of slots 14 formed in the stator core 13. An armature winding 15 that is a three-phase winding wound around the slot 14 in a concentrated winding is formed.

  On the other hand, the rotor 30 disposed inside the stator 10 has a rotor core 31 in which a large number of electromagnetic steel plates are laminated. The rotor core 31 faces the inner surface of the tooth 12, and the teeth 12. Rotate to move relative to. Here, the teeth 12 of the magnet motor 1 are 42 pieces, the number of rotor stations is 56 poles, and the permanent magnet piece 32 uses ferrite as a magnet element to constitute a thin, lightweight, high torque magnet motor 1. ing. Further, the outer peripheral surface shape of the rotor core 31 is a non-concentric shape that is convex toward the stator 10 side.

  As shown in FIG. 3, the rotor 30 is integrally fixed by molding a large number of rotor cores 31 and permanent magnet pieces 32 with a resin material to form an annular primary molded body 51. Specifically, the outer diameter side of the permanent magnet piece 32 (the surface facing the stator side) is covered with the outer peripheral mold 71a, and the inner diameter side of the permanent magnet piece 32 is covered with the inner peripheral mold 71b. By filling the strength reinforcing hole 50 provided in the central portion of the rotor core 31 with the strength reinforcing mold 33, the primary mold body 51 is formed. Thereby, the permanent magnet piece 32 is sandwiched between the rotor cores 31 from both sides in the rotational direction and is also supported by the rotor core 31 via the resin material in the radial direction.

  The rotor core 31 and the permanent magnet pieces 32 are alternately arranged radially from the center of the rotation axis, and are arranged so as to form a cylindrical shape. Here, the permanent magnet piece 32 is made of a magnet element in a non-magnetized state, and is magnetized after forming the primary mold body 51 of the rotor 30 as described later. That is, when the permanent magnet piece 32 is assembled, the permanent magnet piece 32 is not magnetized, thereby preventing the confirmation of the magnetization direction of the permanent magnet piece 32 and erroneous insertion. There is no risk of the piece 32 being incorporated. Further, since a plurality of non-magnetized permanent magnet pieces 32 can be arranged to form an annular assembly, it is easy to mount the permanent magnet pieces 32 and the productivity of the rotor 30 and the magnet motor 1 is improved. .

  Further, the gap between the outer diameter side and the inner diameter side of the permanent magnet piece 32 acts so as to reduce the leakage magnetic flux of the permanent magnet piece 32, and the magnetic flux is efficiently applied to the permanent magnet piece 32 at the time of magnetization described later. Acts to be captured. For this reason, the rotor 30 and the magnet motor 1 which have a desired magnetic flux amount are obtained.

  Next, after the permanent magnet piece 32 is externally magnetized, the boss portion 37 is simultaneously molded and integrated with the resin material 34 to form a secondary mold body 90. When the secondary molding is performed, the resin material 34 is filled into the keyhole-shaped connection hole 60 provided on the inner diameter side of the rotor core 31 and fused. Thereby, even when the rotor 30 rotates at a high speed (during the dehydration process), 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 is provided. Can do. It can be visually confirmed from the axial direction of the rotor 30 that the keyhole-shaped connection hole 60 is filled with the resin material 34.

  FIG. 4 is a diagram showing a plane and a front surface of the rotor of the magnet motor 1 of FIG. 2, and in the plan view of FIG. 4a, a front view along the section EE is FIG. 4b. As described in FIG. 2, A in the upper part of FIG. 4B represents a cross section including the permanent magnet piece 32, and B in the lower part of FIG. 4B represents a cross section including the rotor core 31. As shown in FIG. 4, a boss portion 37 as a connecting member of the rotating shaft 22 is provided inside the rotor 30 and is fixed integrally with the rotor by a resin material 34 for secondary molding. ing.

  Here, the manufacturing method of the magnet motor 1 which has the above rotors 30 is demonstrated using FIGS. FIG. 5 is a view showing a state in which the rotor cores 31 and the permanent magnet pieces 32 of the magnet motor 1 of FIG. 2 are alternately arranged to form an annular shape. In the first stage of the manufacturing process, as shown in FIG. 5, the primary rotor assembly 40 of the rotor core 31 and the permanent magnet piece 32 is formed. At this time, first, the rotor cores 31 are all arranged using a jig or the like (not shown), and then the permanent magnet pieces 32 are inserted between the rotor cores 31 so that the primary rotor groups are alternately arranged. The appendage 40 is obtained. In this state, the permanent magnet piece 32 is not yet magnetized, so that it can be smoothly inserted between the rotor cores 31.

  As a method for positioning the rotor core 31, a pin (not shown) that can be engaged with a keyhole-shaped connection hole 60 provided on the inner surface of the rotor core 31 is provided in the jig, and the connection hole 60 is provided in the pin. By engaging, it can be positioned. Further, at this time, by providing the jig with a holding portion that holds the outer diameter portion of the rotor core 31, it is possible to suppress the inclination of the rotor core 31 in the circumferential direction.

  Next, the primary rotor assembly 40 is placed in the mold, and a resin material for primary molding is poured. Thereby, the primary mold body 51 integrally fixed with a synthetic resin as shown in FIG. 6 is obtained. Thereafter, an outer magnetized yoke is disposed on the outer side of the annular primary mold body 51, an inner magnetized yoke is disposed on the inner diameter side of the primary mold body 51, and the permanent magnet pieces 32 are magnetized in the circumferential direction. Magnetize.

  After the magnetization, as shown in FIG. 7, the iron core support base 36 and the boss portion 37 are respectively arranged inside the primary mold body 51. Then, a resin material 34 for secondary molding is poured, and a secondary mold body 90 is obtained in which these are integrally fixed by the resin material 34, and the rotor 30 is formed.

  Thereafter, as shown in FIG. 2, the rotor 30 is arranged on the inner diameter side of the stator 10 fixed to the stator base 20 and fixed to the rotating shaft 22, whereby the magnet motor 1 is obtained. In the present embodiment, since ferrite is used as the magnet element of the permanent magnet piece 32, it is easier to obtain than the rare metal, and the productivity of the rotor 30 and the magnet motor 1, and also a washing machine using them is improved. .

  In the present embodiment, the above-described rotor has been improved as follows. FIG. 8 is an enlarged view of the rotor core 31 and the permanent magnet piece 32 showing the dimensions of each part. Of particular interest is the relationship between the magnet thickness dimension T of the permanent magnet piece 32 sandwiched between the rotor cores 31 and the inner diameter side gap dimension W of the magnet. In other words, a gap is formed on the inner diameter side of the magnet, but this gap is supported by the protrusions 101 formed on the inner diameter side of the iron cores on both sides. For this reason, the dimension W (inner diameter side gap portion dimension W) of the portion in contact with the gap portion on the inner diameter side of the magnet is narrower than the magnet thickness dimension T of the magnet.

  By adopting this arc-shaped magnet, the magnet retaining portion in the inner diameter side circumferential direction of the rotor core 31 can be made smaller, that is, the dimension W of the inner diameter side gap 41 can be made larger, so that leakage flux can be reduced. As shown in FIG. 8, even if the magnet retaining portion is made smaller, the convex radius R2 and concave radius R1 of the magnet are non-concentric, so the magnet is restrained from moving in the radial direction, and the conventional magnet The effect of reducing the retaining part is small.

  FIG. 9 is a diagram illustrating the relationship among the inner diameter side gap dimension W, the magnet thickness dimension T, and the induced voltage constant of the rotor core 31. Here, with respect to the current product, the improved product 1 and the improved product 2, the magnet thickness T (mm) is kept constant at 5.5 (mm), and the inner diameter side gap dimension W (mm) of the rotor core 31 is set. The induced voltage constant (pu) of the magnet motor 1 when changed was calculated. Here, the induced voltage constant at the dimension of the current product is unitized and indicated as 1 (pu).

  As is clear from this dimensional ratio W / T, the current product has an inner diameter side gap dimension W (mm) of 3 (mm), which means that about half of the current product is on the inner diameter side of the magnet. It can be understood that the shape is supported by the protrusion 101 formed on the inner diameter side of the.

  According to this comparison result, it can be understood that there is a relationship that the induced voltage constant increases as the inner diameter side gap W dimension (mm) increases. That is, it is clear that if the magnet retaining portion 101 is made smaller and the dimension W of the inner diameter side gap portion 41 is made larger, the leakage flux of the magnet is reduced and the induced voltage constant is increased.

  FIG. 10 is a diagram showing the relationship of FIG. 9 with the dimensional ratio W / T on the horizontal axis and the induced voltage constant (pu) on the vertical axis. In contrast to the current product with a dimensional ratio W / T of 0.55, the induced voltage constant (pu) increases to 1.11 at the dimensional ratio W / T (0.78) of the improved product 1, and the improved product 2 At the dimensional ratio W / T (1.02), the induced voltage constant (pu) increases to 1.09.

  From this result, although the induced voltage constant (pu) tends to increase when the magnet retaining portion 101 is made smaller, it is considered to include a local maximum point. The reason for having the maximum point can be estimated as follows.

  First of all, it is considered that the amount of leakage magnetic flux from this portion decreases as the magnet retaining portion 101 becomes smaller, and as a result, the induced voltage increases. Further, when the magnet retaining portion 101 is further reduced, it is considered that the required magnetic flux amount is reduced and the induced voltage is reduced. Note that it is not necessary to simply increase the dimension of the inner diameter side gap 41. If the dimension is larger than the magnet thickness T, the resin easily enters between the circumferential direction of the permanent magnet piece 32 and the rotor core 31, and the magnet There arises a problem that the magnetic flux cannot be effectively extracted. Further, structurally, there is a possibility that the keyhole-shaped connection hole 60 of the rotor core 31 cannot be formed. According to the experiments by the inventors, it was found that the ratio of the dimension W of the air gap 41 to the magnet thickness T is 0.78, which has the highest induced voltage and is appropriate.

  According to the present embodiment in which the characteristics of FIG. 10 are clarified, an effect that the induced voltage can be increased when the dimensional ratio W / T is 0.6 or more is obtained. The fact that the induced voltage can be increased means that the current can be small when compared with motors of the same ability, which can contribute to energy saving. Furthermore, when the dimensional ratio W / T is 0.6 or more and less than 0.8, the support effect by the magnet retaining portion 101 can be expected, and rattling of the magnet support can be prevented. On the other hand, in the region of 0.8 or more, the effect of preventing rattling is reduced. On the other hand, even if a dimensional error in manufacturing the magnet retaining portion 101 occurs, the change in induced voltage constant (pu) can be reduced. Therefore, manufacturing variations can be tolerated.

  Thus, according to the present embodiment, the leakage magnetic flux of the permanent magnet piece 32 is reduced, and the permanent magnet piece 32 is easily magnetized during magnetization. Therefore, the desired amount of magnetic flux can be obtained, and the rotor 30 and the magnet motor 100 that are more excellent in rotational performance can be obtained.

  Next, the laminated structure of the rotor core 31 will be described in detail. As shown in FIG. 11a, each rotor core 31 in the present embodiment is not straight in the radial direction on both sides in the circumferential direction, and has a convex curve on one side and a concave curve on the opposite side, It is also characterized by an arcuate shape. For this reason, it is possible to restrain the movement of the permanent magnet piece 32 arrange | positioned between the rotor core 31 and the rotor core 31 adjacent to this.

  The rotor core 31 has laminated fastening portions 52 a and 52 b, and the laminated electromagnetic steel plates are fastened by the laminated fastening portion 52. However, if the laminated fastening portion 52 is formed on the center line 53 of the rotor, the distance between the circumferential side end (concave curved portion) of the rotor core 31 and the fastening portion is reduced, and fastening strength may be insufficient. There is. If the fastening strength is insufficient, before the permanent magnet piece 32 and the rotor core 31 are molded with the resin material, the lamination is peeled off or divided into a plurality of parts by the molding pressure and fixed as it is. Will be significantly reduced.

  Therefore, in the present embodiment, the plurality of laminated fastening portions 52 are formed side by side so as to be positioned at the center in the width direction of the rotor core 31. Specifically, as shown in FIG. 12, the laminated fastening portion 52a is positioned so that the distances a1 and a2 that are vertically extended with respect to the arc portions on both sides are substantially the same, and the laminated fastening portion 52b is at a position where b1 and b2, which are distances extending vertically with respect to the arc portions on both sides, are substantially the same. For this reason, the fastening strength of the lamination | stacking of the rotor core 31 increases, and the reliability of the magnet motor 1 improves. The strength reinforcing hole 50 for filling and molding the resin material is formed between the laminated fastening portion 52a and the laminated fastening portion 52b, and desirably the distance c1 between the laminated fastening portion 52a and the strength reinforcing hole 50. Are arranged so that the distance c2 between the laminated fastening portion 52b and the strength reinforcing hole 50 is substantially the same. Thereby, it becomes possible to support the rotor core 31 more reliably.

  In addition, although this embodiment demonstrated the magnet motor 1 used for a drum type washing machine, you may use the above magnet motors 1 for a vertical washing machine.

DESCRIPTION OF SYMBOLS 1 Magnet motor 10 Stator 13 Stator core 14 Slot 15 Armature winding 30 Rotor 31 Rotor core 32 Permanent magnet piece 33 Strength reinforcement mold 34 Resin material 40 Primary rotor assembly 50 Strength reinforcement hole 51 Primary mold body 52 Laminate Connecting Portion 53 Rotor Center Line 60 Connecting Hole 71 Inner and Outer Mold 90 Secondary Molded Body 100 Drum Type Washer / Dryer

Claims (4)

  A stator and a rotor that rotates relative to the stator are provided, and the rotor has an annular shape in which permanent magnet pieces and a rotor core are alternately arranged radially, and the rotor core is made of an electromagnetic steel plate. In the magnet motor configured by stacking, the permanent magnet and the rotor core are formed in a bow shape, and the distance between the laminated fastening portions of the rotor core and both circumferential ends of the rotor core is substantially the same. A magnet motor, wherein a plurality of magnet motors are provided.   2. The magnet motor according to claim 1, wherein the distance between the reinforcing hole filled with the resin material and each of the laminated fastening portions is substantially the same.   2. The magnet according to claim 1, wherein a dimension ratio W / T is 0.6 or more, where T is a thickness dimension in the annular direction of the permanent magnet piece and W is an inner diameter side dimension of the permanent magnet piece. motor.   A stator and a rotor that rotates relative to the stator, wherein the rotor has an annular shape in which permanent magnet pieces and a rotor core are alternately arranged radially, and the rotor core is a magnetic steel sheet; In the washing machine including the magnet motor configured by laminating the rotor core, one end in the circumferential direction of the rotor core has a convex curved surface, and the other end in the circumferential direction of the rotor core is a concave curved surface. And a plurality of laminated fastening portions of the rotor core are provided at a substantially central portion in the width direction of the rotor core.