JP2020068563A - Magnet motor and washing machine with the same - Google Patents

Abstract

To provide a magnet motor capable of increasing the fastening strength of stacking of rotational iron cores while suppressing performance deterioration to improve reliability.SOLUTION: A magnet motor includes a stator 10, and a rotor 30 that rotates relative to the stator 10. The rotor 30 is formed in a ring shape with permanent magnet pieces 32 and rotor cores 31 alternately disposed in a radial fashion. In the rotor cores 31, stacked magnetic steel sheets are fastened with a fastening part 52. Each of the rotor cores 31 is formed in an arch shape, and one end side in a circumferential direction has a convex shape, and the other end side in the circumferential direction has a concave, curved surface part. The fastening part 52 is formed in a rectangular form, and includes: an outer diameter side fastening part 52a positioned in parallel to a rotor core center line 53 on the radially outer side of each rotor core 31; and an inner diameter fastening part 52b positioned orthogonal to the rotor core center line 53 on the inner diameter side. When the height in the radial direction of each rotor core 31 is H and a distance from the outer diameter end of each rotor core 31 to a center of the outer diameter side fastening part 52a is h1, h1/H is 0.14 to 0.17.SELECTED DRAWING: Figure 5

Description

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

  In the current drum type washer / dryer, a method in which a magnet motor is directly connected to a rotating shaft of a washing tub and driven (a direct drive method, hereinafter, a DD method) has become mainstream. Usually, in a drum type washer / dryer, it is necessary to drive the washing tub at low speed and high torque in the washing process, so rare metals, i.e., neodymium magnets were previously used as the magnetic material. Recently, inexpensive ferrite magnets have been adopted.

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

  For example, in Patent Document 1, permanent magnet pieces are arranged radially, the magnetization direction of the permanent magnets is set to the circumferential direction, and the permanent magnet pieces and the rotor core are arranged alternately to form an annular shape. A brushless motor with a rotor is disclosed. Further, both circumferential ends of the permanent magnet piece and the rotor core are shaped so as to linearly extend in the radial direction.

JP2012-217269A

  The laminated fastening portions of the laminated rotor cores are arranged on the central axis of the magnetic poles in consideration of magnetic balance. However, unlike the magnet motor disclosed in Patent Document 1 described above, the shapes of the permanent magnet piece and the rotor iron core in the circumferential direction on both sides in the circumferential direction are not linear, and if the laminated fastening points are arranged on the center line of the rotor, rotation will occur. There is a possibility that the distance from the circumferential side end of the child iron core to the laminated fastening point becomes short and fastening strength becomes insufficient. If the fastening strength is insufficient in this way, the laminated layers may be peeled off before molding the permanent magnet pieces and the rotor core, or they may be split into multiple pieces by the molding pressure and adhered as they are, resulting in a significant decrease in motor performance. Occurs. Therefore, in order to secure the fastening strength, a structure in which the fastening core structure is V-shaped or U-shaped to crimp the laminated cores is used. In this case, there is a concern that the insulating coating coated on the laminated iron plates will be broken, the crimped portion will be electrically conducted, and eddy current loss will occur in the crimped portion, degrading the motor performance.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnet motor that enhances the fastening strength of laminated rotor cores while suppressing performance degradation and improves reliability.

  In order to achieve the above object, a magnet motor of the present invention has a stator and a rotor that rotates with respect to the stator, and the rotor has permanent magnet pieces and rotor cores arranged alternately in a radial pattern. The rotor iron core is a magnet motor in which laminated electromagnetic steel plates are fastened at the fastening portion, and the rotor iron core is formed in an arc shape, and one end side in the circumferential direction is convex, And the other end in the circumferential direction has a concave curved surface portion, the fastening portion is rectangular, and the outer diameter side fastening portion arranged on the outer diameter side of the rotor core parallel to the rotor core center line, It has a rotor core center line on the inner diameter side and an inner diameter side fastening portion arranged orthogonally, and the radial height of the rotor iron core is H, and the center of the outer diameter side fastening portion from the outer diameter end of the rotor iron core. When the distance to is set to h1, h1 / H is set to 0.14 to 0.17.

  It is possible to provide a magnet motor having improved reliability by increasing the fastening strength of laminated rotor cores while suppressing performance deterioration.

1 is a schematic view of a drum type washer / dryer according to an 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 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 formed the rotor core and the permanent magnet by turns, and formed it in the annular 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 body and the boss part in the primary mold body. It is the figure which expanded the rotor core. It is the figure which showed the dimensional relationship about FIG. It is the figure which showed the cross-sectional shape of a crimping part. It is the result of sensitivity analysis by the experimental design method of the influence of the size of each part of the fastening part on the eddy current loss.

  Hereinafter, a drum type washing machine 100 according to an embodiment of the present invention and a magnet motor used therein will be described with reference to FIGS. 1 to 11.

  FIG. 1 is a schematic view of a drum type washer / dryer 100 according to the present embodiment. The drum type washer / dryer 100 includes a housing 101 having a front panel opened, and a housing base 102 having rubber legs at four corners. A door 103 can be opened and closed at the opening of the housing 101. It is installed. Further, the casing 101 includes an outer tub 105 including a rotary drum 104 as an inner tub (laundry tub). A magnet motor 1 (not shown) that rotationally drives the rotary drum 104 is attached to this back surface. Then, by the rotation of the rotating drum 104, a washing process, a rinsing process, a dehydrating process, etc. are executed.

  FIG. 2 is an axial sectional view of the magnet motor 1 according to this embodiment. Here, A of the upper portion of the portion where the stator 10 and the rotor 30 face each other shows a cross section including the permanent magnet piece 32, and B of the lower portion shows a cross section including the rotor core 31. ing. As shown in FIG. 2, the magnet motor 1 includes a stator 10, a stator base 20, a rotor 30, bearings 26 (26 a, 26 b), and a bearing boss portion 22 a provided on the rotary shaft 22. 22b, a rotary shaft 22 rotatably supported by a bearing 26 and fixedly supporting the rotor 30, and the like. The stator 10 is fixed to the stator base portion 20 by fastening bolts 21, the rotor 30 is fitted to bearing bosses 22a and 22b provided at the end of the rotary shaft 22, and the screw portion 24 and the nut. It is fixed by 25. Further, bearings 26 (26a, 26b) are arranged on the inner peripheral side of the stator base portion 20 and the outer peripheral side of the rotary shaft 22, and the rotor 30 can freely rotate on the inner peripheral side of the stator 10. Is supported as.

  FIG. 3 is a radial cross-sectional view of the magnet motor 1 of FIG. 2, showing an enlarged view of the portion where the stator 10 and the rotor 30 face each other. Further, FIG. 4 is a view showing a plane and a front surface of the rotor of the magnet motor 1 of FIG. First, the stator 10 includes a stator core 13 having a core back 11 and teeth 12 fitted in a housing 18 (not shown), and a plurality of slots 14 formed in the stator core 13. It is composed of an armature winding 15 which is a three-phase winding wound around the slot 14 by concentrated winding.

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

  As shown in FIG. 3, the rotor 30 is formed by molding a large number of rotor cores 31 and permanent magnet pieces 32 with a resin material to integrally fix the rotor cores 31 to form an annular primary mold body 51. Specifically, the outer peripheral side of the permanent magnet piece 32 (the surface facing the stator side) is covered with the outer peripheral mold 71a, and the inner peripheral side cavity of the permanent magnet piece 32 is covered with the inner peripheral mold 71b. Then, the primary mold body 51 is formed. As a result, the permanent magnet pieces 32 are sandwiched between the rotor cores 31 from both sides in the rotation direction and are also supported by the rotor cores 31 in the radial direction via the resin material.

  The rotor cores 31 and the permanent magnet pieces 32 are alternately arranged radially from the center of the rotation axis and arranged so as to form a cylindrical shape. Here, the permanent magnet piece 32 uses 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, at the time of assembling the permanent magnet piece 32, the permanent magnet piece 32 is not magnetized, so that the confirmation direction of the permanent magnet piece 32 does not leak and the insertion error does not occur. There is no risk that the piece 32 will be incorporated. Further, since a plurality of non-magnetized permanent magnet pieces 32 can be arranged to form an annular assembly, the permanent magnet pieces 32 can be easily attached, 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. It acts to be taken in. Therefore, the rotor 30 and the magnet motor 1 having the desired magnetic flux amount can be obtained.

  After the permanent magnet piece 32 is magnetized externally, the boss portion 37 is simultaneously molded by the secondary molding resin material 34 and integrated to form a secondary molding body 90. At the time of secondary molding, the secondary molding resin material 34 is filled in the positioning hole 54 provided in the rotor core 31 and the keyhole-shaped connecting hole 60 and fused. Accordingly, even when the rotor 30 rotates at a high speed (during a dehydration step), it is possible to maintain the coupling strength between the rotor core 31 and the permanent magnet pieces 32, and to provide a strong fixing structure that resists centrifugal force. You can The fact that the secondary molding resin material 34 is filled in the keyhole-shaped connecting hole 60 can be visually confirmed from the axial direction of the rotor 30.

  In the plan view of FIG. 4A, a front view taken along the line AA is FIG. 4B. As described in FIG. 2, the upper portion A of FIG. 4B shows a cross section including the permanent magnet piece 32, and the lower portion B of FIG. 4B shows a cross section including the rotor core 31. is doing. As shown in FIG. 4, a boss portion 37 as a connecting member of the rotary shaft 22 is provided inside the rotor 30, and is fixed integrally with the rotor by a secondary molding resin material 34. .

  Here, a method of manufacturing the magnet motor 1 having the rotor 30 as described above will be described with reference to 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 and formed into an annular shape. At the first stage of the manufacturing process, as shown in FIG. 5, the rotor core 31 and the primary rotor assembly 40 of the permanent magnet piece 32 are formed.

  At this time, after all the rotor cores 31 are arranged by using a jig or the like (not shown), the permanent magnet pieces 32 are inserted between the rotor cores 31 to assemble the primary rotors arranged alternately. A body 40 is obtained. In this state, the permanent magnet piece 32 is not magnetized yet, so that it can be smoothly inserted between the rotor cores 31.

  As a method for positioning the rotor iron core 31, a jig (not shown) that can be engaged with the positioning hole 54 provided in the rotor iron core 31 and the keyhole-shaped connecting hole 60 is provided in the jig, and the positioning hole is provided in the pin. By engaging 54 and the connecting hole 60, positioning can be performed with high accuracy. 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 the primary molding resin material 33 is poured. As a result, the primary mold body 51 integrally fixed with the synthetic resin as shown in FIG. 6 is obtained. After that, the outer magnetizing yoke is arranged on the outer shape side of the annular primary mold body 51, the inner magnetizing yoke is arranged 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 arranged inside the primary mold body 51. Then, a secondary mold resin material 34 (not shown) is poured, and a secondary mold body 90 is obtained in which these are integrally fixed by the secondary mold resin material 34 (not shown). It 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 rotary 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 more easily available than rare metal, and the productivity of the rotor 30, the magnet motor 1, and the washing machine using these is improved. .

  In the present embodiment, the rotor as described above has been devised and improved as follows. FIG. 8 is an enlarged view of the rotor core 31, and FIG. 9 is a view showing dimensions of respective parts with respect to FIG. Further, FIG. 10 is a cross-sectional view of the fastening portion 52 taken along the line AA ′ of one electromagnetic steel sheet, and FIG. 11 is a sensitivity analysis result by an experimental design method of the influence of the dimensions of each fastening portion 52 on the eddy current loss. . Specifically, the width dimension of the fastening portion 52 is represented by the ratio of the sheet thickness of the electromagnetic steel sheet, the thickness dimension of the fastening portion 52 is represented by the ratio of the sheet thickness of the electromagnetic steel sheet, the position h1 of the outer diameter side fastening portion. Is a diagram in which the eddy current loss (db) at the fastening portion is plotted on the vertical axis with respect to the dimension of each portion that represents the position h2 of the fastening portion on the inner diameter side by the ratio of the radial height H of the rotor core. Large eddy current loss.

  As shown in FIG. 8, each of the rotor cores 31 in the present embodiment is not linear in the radial direction on both sides in the circumferential direction, but has a curved surface portion having a convex shape on one side (one side in the circumferential direction) and on the other side. It is also characterized in that (the other end side in the circumferential direction) has a concave curved surface portion and has an arcuate shape as a whole. Therefore, it is possible to restrain the movement of the permanent magnet piece 32 (not shown) arranged between the rotor core 31 and the rotor core 31 adjacent thereto.

  In addition, a rectangular outer diameter side fastening portion 52a and an inner diameter side fastening portion 52b are formed as fastening portions 52 on the rotor core 31, and the laminated electromagnetic steel plates are fastened by the fastening portions 52. There is. In the present embodiment, the plurality of laminated fastening portions 52 are formed so that the outer diameter side fastening portions 52a are parallel to the rotor core center line 53 of the rotor core 31 and the inner diameter side fastening portions 52b are orthogonal to each other. is doing.

  As described above, the positioning hole 53 is formed between the outer diameter side fastening portion 52a and the inner diameter side fastening portion 52b of the rotor iron core 31, and the connecting hole 60 is formed on the inner diameter end side of the stator iron core 31. ing.

  Further, the arrangement of the fastening portion 52 shown in FIG. 8 is the dimension specifications shown in FIG. 9, that is, the distance from the outer diameter end of the rotor core to the center of the outer diameter side fastening portion 52a in the radial direction (longitudinal direction) is h1, When the distance from the outer diameter end of the rotor core to the radial (thickness direction) center of the inner diameter side fastening portion 52b is h2, and the radial height of the rotor core is H, the ratio of h1 / H is 0.17, h2 The ratio of / H is 0.62.

  Further, the cross-sectional shape of the fastening portion 52 shown in FIG. 10 (a) is a bathtub shape as shown in FIG. 10 (d), and is fastened and fastened to another laminated electromagnetic steel sheet. . Here, the cross-sectional structure of the fastening portion 52 may be V-shaped as shown in FIG. 10B or U-shaped as shown in FIG. 10C.

  10B to 10D are described as cross-sectional examples of the outer diameter side fastening portion 52a in FIG. 10A, the same applies to the cross section of the inner diameter side fastening portion 52b.

  Here, when the cross-sectional shape of the fastening portion 52 is V-shaped or U-shaped as shown in FIGS. 10B and 10C, since the insulating coating of the electromagnetic steel plate is broken, the fastening portion 52 is axially formed. Will be electrically connected to. In this case, when a harmonic magnetic flux (not shown) from the stator 10 interlinks between the outer diameter side fastening portion 52a and the inner diameter side fastening portion 52b, the outer diameter side fastening portion 52a and the inner diameter side fastening portion 52b are connected. Since a voltage is induced between the two, an eddy current flows along a current loop composed of the electrically connected outer diameter side fastening portion 52a and the inner diameter side fastening portion 52b, resulting in eddy current loss and motor performance. There is a concern that it will worsen.

  However, even if the cross-sectional shape of the fastening portion 52 is V-shaped or U-shaped, it has been found from the experimental results that the object of the present invention can be achieved within the following dimensional range. The details will be described below.

  As a result of an experiment, it has been clarified that the relationship shown in FIG. 11 is obtained when the sensitivity (db) to the eddy current loss of the fastening portion is taken with respect to the dimensional ratio of each portion of the fastening portion 52. That is, from FIG. 11, it can be confirmed that the eddy current loss tends to increase as the width of the fastening portion increases, and the thickness of the fastening portion has less sensitivity to the eddy current loss.

  Further, the position dimension ratio (h1 / H) of the outer diameter side fastening portion 52a is reduced (the outer diameter side fastening portion 52a is brought closer to the outer diameter nearest to the rotor core 31), or the position dimension of the inner diameter side fastening portion 52b. When the ratio (h2 / H) is increased (the inner diameter side fastening portion 52b is brought closer to the inner diameter closest to the rotor iron core 31), the eddy current loss generated in the fastening portion 52 increases, and decreases in the opposite relationship. It turns out that

  The reason for this is that when h1 / H is made small or h2 / H is made large, the winding coefficient of the one-turn coil composed of the outer diameter side fastening portion 52a and the inner diameter side fastening portion 52b becomes large. Since the amount of harmonic magnetic flux interlinking increases, the eddy current loss also increases. On the other hand, as the dimension ratio h1 / H is increased and h2 / H is decreased, the outer diameter side fastening portion 52a is separated from the outer diameter end of the rotor core 31, so that the influence of the harmonic magnetic flux is reduced and the eddy current loss is reduced. The generation amount of is also small. Here, when the upper limit that affects the washing machine performance due to the occurrence of eddy current loss is shown by the dashed line in the figure, the dimension ratio h1 / H is 0.14 to 0.17, and the dimension ratio h2 / h is 0.51 to 0.62. It is the applicable range of the position.

  Therefore, from FIG. 11, it can be said that the eddy current loss generated in the fastening portion 52 can be substantially suppressed by setting the dimensional ratio h1 / H to 0.14 to 0.17 and the dimensional ratio h2 / h to 0.51 to 0.62.

  Further, when the dimension ratio h1 / H is further increased, or when the dimension ratio h2 / H is further reduced, the outer diameter side fastening portion 52a and the inner diameter side fastening portion 52b are brought into close proximity to each other. The shape of 54 may be deformed, and the fastening strength of the rotor core 31 may be hindered. Therefore, in the present invention, the dimensional ratio h1 / H is set to 0.17 and the dimensional ratio h2 / H is set to 0.62 as the upper limit values that do not hinder the fastening strength. It is desirable that the lower limit value be zero for eddy current loss, but it is not necessary, but it is actually difficult to reduce overcurrent loss to zero due to various factors. Here, as the range of values obtained in the experiment, the dimensional ratio h1 / H is 0.14, and the dimensional ratio h2 / h is 0.51.

  As described above, according to the present embodiment, it is possible to provide a magnet motor that enhances the fastening strength of laminated rotor cores and improves reliability.

  Although the magnet motor 1 used in the drum type washing machine has been described in the present embodiment, the magnet motor 1 as described above may be used in a vertical washing machine.

1 Magnet Motor 10 Stator 11 Core Back 12 Teeth 13 Stator Iron Core 14 Slot 15 Armature Winding 18 Housing 20 Stator Base 21 Fastening Bolt 22 Rotating Shaft 22a Bearing Boss 22b Bearing Boss 24 Screw 25 Nut 26 Bearing 30 Rotor 31 Rotor iron core 32 Permanent magnet piece 33 Primary mold resin material 34 Secondary mold resin material 36 Iron core support base 37 Boss portion 40 Primary rotor assembly 51 Primary mold body 52 Fastening portion 52a Outer diameter side fastening portion 52b Inner diameter side Fastening part 53 Rotor iron core center line 54 Positioning hole 60 Connection hole 90 Secondary mold body 100 Drum type washer / dryer 101 Housing 102 Housing base 103 Door 104 Rotating drum 105 Outer tank

Claims (6)

A stator and a rotor that rotates with respect to the stator, and the rotor has a circular shape in which permanent magnet pieces and rotor iron cores are radially arranged alternately, and the rotor iron core is A magnet motor in which laminated electromagnetic steel plates are fastened at a fastening portion,
The rotor core is formed in an arc shape, and has a curved surface portion that is convex on one end side in the circumferential direction and concave on the other end side in the circumferential direction,
The fastening portion is
Rectangular,
An outer diameter side fastening portion arranged on the outer diameter side of the rotor core parallel to the center line of the rotor core,
On the inner diameter side of the rotor core, the inner diameter side fastening portion arranged orthogonally to the rotor core center line,
When the radial height of the rotor core is H, and the distance from the outer diameter end of the rotor core to the center of the outer diameter side fastening portion is h1, h1 / H is 0.14 to 0.17. Characteristic magnet motor. The magnet motor according to claim 1, wherein
The fastening portion, when the distance from the outer diameter end of the rotor core to the center of the inner diameter side fastening portion is h2, h1 / H is 0.14 to 0.17, and h2 / H is 0.51 to 0.62. There is a magnet motor. The magnet motor according to claim 1 or 2, wherein
The cross-sectional shape of the fastening portion is a bathtub-shaped magnet motor. The magnet motor according to claim 1 or 2, wherein
A magnet motor in which the fastening portion has a V-shaped or U-shaped cross-section. The magnet motor according to any one of claims 1 to 5,
The rotor core has a positioning hole formed between the outer diameter side fastening portion and the inner diameter side fastening portion and a keyhole-shaped coupling hole.   A washing machine to which the magnet motor according to any one of claims 1 to 5 is applied.

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