JPWO2008126408A1 - Drum washing machine - Google Patents

Abstract

The drum type washing machine of the present invention is a direct drive type washing machine including a washing machine casing, a rotating drum having a drum rotating shaft in a horizontal direction or an inclined direction, and a motor for driving the rotating drum. This motor includes a twin rotor including a stator wound with a toroidal winding and a first mold resin, an outer rotor, an inner rotor, and a second mold resin for integrally molding them. With.

Description

  The present invention relates to a direct drive type drum-type washing machine including a rotating drum having a rotation center axis in a horizontal direction or an inclination direction and a motor for driving the rotating drum.

  In recent automatic washing machines, a direct drive drum washing machine with a drying function has become mainstream. Since the motor that drives the rotating drum of the washing machine directly drives the rotating drum without using a gear, low speed and high torque during washing (from 10 rpm to 100 rpm, 10 N · m or more) and high speed and low torque during dehydration ( 1000 rpm or more) must be realized at the same time. Further, since the speed is very low during washing, it is necessary to reduce the cogging torque of the motor that greatly affects the vibration and noise of the washing machine.

  As a technique for realizing such a motor that outputs low speed and high torque, a motor for a washing machine as described in Patent Document 1 and Patent Document 2 is known. The washing machine motor described in these patent documents includes a stator and a rotor disposed on the outer periphery of the stator. However, as described in Patent Document 1, in order to produce a large torque with a motor having only one stator and only one rotor, the amount of coils wound around the stator is increased, or the magnet strength of the rotor is increased. Have to do. For this reason, the problem that the volume became large as a whole occurred. Furthermore, the washing machine motor described in Patent Literature 1 includes a coil wound around the stator by a concentrated winding method. For this reason, radial force will become large compared with the motor provided with the coil wound by the distributed winding system. As a result, there has been a problem that noise and vibration during driving increase.

  In order to solve the above problem, a motor as described in Patent Document 2 has been proposed. The motor described in Patent Document 2 includes a hollow cylindrical stator having coils wound around teeth by a concentrated winding method, and an inner side arranged with a uniform gap with respect to the inner peripheral surface of the stator. And a rotor and an outer rotor disposed with a uniform gap with respect to the outer peripheral surface of the stator. The motor described in Patent Document 2 having such a configuration can use the force caused by the magnetic flux of the inner rotor and the force caused by the magnetic flux of the outer rotor. For this reason, it is possible to increase the output density and output a large torque while being small.

  However, the motor described in Patent Document 2 also includes a coil wound by the concentrated winding method, and thus the radial force increases. As a result, there has been a problem that vibration and noise during driving increase.

As described above, the drum type washing machine equipped with the washing machine motor described in Patent Document 1 and Patent Document 2 has a problem that it is difficult to simultaneously realize high capacity, compactness, and low noise. Was.
JP 2007-089282 A JP-T-2005-521378

  The drum type washing machine of the present invention has the following configuration. A washing machine housing having an opening for taking in and out laundry, a rotating drum having a drum rotating shaft in a horizontal direction or an inclined direction with respect to the housing, and a motor for driving the rotating drum. The rotating shaft is a direct drive type washing machine directly connected to the motor shaft.

  The stator of the motor includes an annular stator yoke, a plurality of outer teeth projecting from the stator yoke in the outer circumferential direction, a plurality of inner teeth projecting from the stator yoke in the inner circumferential direction by the same number as the outer teeth, A plurality of outer slots configured between the teeth and a plurality of inner slots configured between the inner teeth are included. The stator further includes a coil connected in a three-phase star or delta shape to a stator yoke between the outer slot and the inner slot and wound in a toroidal winding form, a stator yoke, an outer slot, an inner slot, and a coil. And a first mold resin that is integrally molded.

  Further, the rotor of this motor is a twin type rotor, and is arranged with a predetermined air gap facing the outer teeth and a predetermined air gap facing the inner teeth. An inner rotor, a second molding resin that integrally molds the outer rotor and the inner rotor, and a motor shaft coupled to the outer rotor and the inner rotor.

  The drum type washing machine of the present invention with this configuration can increase the washing capacity to the limit while being small, reduce vibration and noise, and can realize quietness that can withstand night driving. . Further, the waterproof / drip-proof performance can be improved, and a highly reliable washing machine can be realized.

FIG. 1 is a cross-sectional view of a drum type washing machine according to an embodiment of the present invention. FIG. 2 is a perspective view of the motor 5 of the drum type washing machine according to the embodiment of the present invention. FIG. 3 is an explanatory perspective view showing the stator and rotor of the motor 5 of the same exploded. FIG. 4 is an explanatory perspective view as seen from a different direction. FIG. 5 is a cross-sectional view of the motor 5 described above. 6 is a cross-sectional view showing a 6-6 cross section in FIG. FIG. 7 is a graph showing the relationship between the tooth tip width and the cogging torque in the motor 5 described above. FIG. 8 is a graph showing the relationship between the rotational position (electrical angle) of the rotor and the induced voltage in the motor 5 described above. FIG. 9 is a graph showing the relationship between the rotational position (electrical angle) of the rotor and the radial force in the motor 5 described above. FIG. 10 is a graph showing the relationship between the rotor rotational position (electrical angle) and the cogging torque in the motor 5 described above. FIG. 11 is a graph showing the motor output density for each motor type in the motor 5 described above. FIG. 12 is a graph showing the relationship between the number of poles and the torque constant in the motor 5 described above. FIG. 13 is a diagram schematically showing a state of a current flowing through the coil 15 in the motor 5 described above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Washing machine housing | casing 1a Opening part 2 Rotating drum 3 Water receiving tank 4 Drum rotating shaft 5 Motor 9 Lid 10 Stator 11 Stator core 12 Outer teeth 13 Inner teeth 14 Stator yoke 15 Coil 16 Outer slot 17 Inner slot 18 Through hole 20 Inner rotor 21 inner rotor yoke 22 inner permanent magnet 30 outer rotor 31 outer rotor yoke 32 outer permanent magnet 41 first surface 42 second surface 51 first mold resin 52 second mold resin 60 mounting portion 61 motor shaft 62 rib 64 air hole 65 Projection 71 Straight line connecting the center of rotation of the outer teeth and the center of rotation of the inner teeth 72 Center arc of the stator yoke

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a drum type washing machine according to an embodiment of the present invention.

  In the washing machine casing 1 of the drum type washing machine, a bottomed cylindrical water receiving tub 3 is disposed in a state of being inclined downward from the front side of the main body 1 toward the back side. The water receiving tub 3 supports the bottomed cylindrical rotary drum 2 on the inner side thereof so that the drum rotary shaft 4 is inclined downward from the front side to the back side of the washing machine casing 1. is doing.

  On the front side of the washing machine casing 1, an opening 1a for taking in and out the laundry is formed. The opening 1a is provided with a lid 9 made of a material such as glass for opening and closing the opening 1a.

  A motor shaft 61 of the motor 5 is directly connected to the outer side of the bottom of the water receiving tank 3 on the same axis as the drum rotating shaft 4 of the rotating drum 2. The motor 5 can control the rotation speed and the rotation direction of the rotary drum 2. In the motor 5, an attachment portion 60 (described later) formed on the outer peripheral portion of the motor 5 is fixed to the water receiving tank 3 by attachment means such as a screw (not shown).

  FIG. 2 is a perspective view of the motor 5 of the drum type washing machine according to the embodiment of the present invention. FIGS. 3 and 4 are exploded perspective views showing the stator 10 of the motor 5 and the twin rotor including the inner rotor 20 and the outer rotor 30. 3 and 4 are perspective views as seen from different directions.

  The motor 5 includes a stator 10, an inner rotor 20 that faces the inner diameter side of the stator 10, and an outer rotor 30 that faces the outer diameter side.

  The substantially entire surface of the stator 10 is covered with the first mold resin 51. Further, the inner rotor 20 and the outer rotor 30 are integrally formed with the second mold resin 52. Five attachment portions 60 are formed on the outer peripheral portion of the stator 10 so as to be arranged at uniform intervals in the rotation direction. The first mold resin 51 of the stator 10 and the second mold resin 52 of the rotor are each integrally formed by being inserted into a resin mold.

  A plurality of air holes 64 penetrating in the direction of the motor shaft 61 are formed in the second mold resin 52 of the rotor. The second mold resin 52 is provided with a plurality of convex portions 65 at portions facing the stator 10 and the motor shaft 61. For this reason, when the inner rotor 20 and the outer rotor 30 rotate, the heat generated from the stator 10 is agitated. Then, hot air in the rotational direction is generated between the stator 10, the inner rotor 20 and the outer rotor 30. This hot air flows out from the air holes 64, and heat in the motor 5 is released. Further, a plurality of ribs 62 are provided on the back side of the second mold resin 52. For this reason, the required intensity | strength can be ensured, reducing the amount of mold resin.

  5 is a sectional view of the motor 5, and FIG. 6 is a sectional view showing a section 6-6 in FIG. The stator core 11 constituting the stator 10 includes a substantially annular stator yoke 14, outer teeth 12 projecting from the stator yoke 14 in the outer circumferential direction, and inner teeth projecting from the stator yoke 14 in the same number as the outer teeth 12. 13 and. In the stator core 11, an outer slot 16 is formed between the outer teeth 12, and an inner slot 17 is formed between the inner teeth 13. The stator 10 further includes a plurality of coils 15 in a toroidal winding system connected in a three-phase star or delta shape, and wound around the stator yoke 14 between the outer slot 16 and the inner slot 17 in a concentrated winding system. Has been.

  Here, in the motor 5 according to this embodiment, the number of poles of the inner rotor 20 and the number of poles of the outer rotor 30 are both 20, and the number of slots is 12 slots. As described above, by using a combination of 20 poles and 12 slots, as will be described in detail later, it is possible to realize an effect equivalent to the distributed winding in the winding arrangement (see FIG. 8).

  As described above, the stator 10 is integrally formed with the first molding resin 51 after winding the coil 15. This is for fixing the coil 15 to the stator core 11 and for preventing moisture and drip. In particular, since the motor 5 is used in a washing machine, it is particularly important to improve moisture resistance and drip-proof performance. Further, in the case where the first molding resin 51 is integrally molded as described above, the molding resin 51 absorbs vibration, and the effect of reducing the vibration and noise of the entire washing machine can be expected.

  The stator yoke 14 of the stator core 11 is formed with a plurality of through holes 18 penetrating in the axial direction. When the coil 15 is integrally formed with the first molding resin 51, the outer slot 16, the inner slot 17, the first surface 41 of the stator yoke 14 (the upper side in FIG. 6), and the second surface 42 of the stator yoke 14. (The lower side in FIG. 6) and the through hole 18 are filled with the mold resin 51. With such a configuration, the first mold resin 51 on the first surface 41 of the stator yoke 14 and the first mold resin 51 on the second surface 42 are filled in the through hole 18. They are connected by the mold resin 51. Therefore, even if the first mold resin 51 on the first surface 41 and the first mold resin 51 on the second surface 42 are formed to be thin for motor miniaturization, the through hole 18 is filled. Since the mold resin 51 is connected, peeling can be prevented. Note that the mounting portion 60 is formed on the second surface 42 by the first mold resin 51.

  The through hole 18 is provided at the intersection of a straight line 71 connecting the center of the outer teeth 12 in the rotational direction and the center of the inner teeth 13 in the rotational direction and passing through the center of rotation and the central arc 72 of the stator yoke 14. The cross-sectional shape of the through hole 18 is preferably circular or elliptical. This is because the fluidity of the mold resin material is improved with this shape.

  Further, the through hole 18 preferably has a radial length of 0.5 ± 10% with respect to the radial length of the stator yoke 14. This is because if the value is larger than this value, the stator yoke 14 may be magnetically saturated and the motor torque may be reduced. If the value is smaller than this value, the fluidity of the mold resin is deteriorated during molding, and the strength is increased. It is because it falls. The cross-sectional shape of the through-hole 18 is not limited to a circle or an ellipse, and a quadrangle, a rectangle, a triangle, or the like can be appropriately employed.

  The first mold resin 51 and the second mold resin 52 are preferably unsaturated polyester resins containing a filler. This is because the fluidity during molding and the strength after molding are excellent.

  FIG. 7 is a graph showing the relationship between the tooth tip width and the cogging torque. The broken line in the figure shows the relationship between the tooth tip width of the inner teeth 13 and the cogging torque when it is assumed that only the inner rotor 20 exists. The solid line indicates the relationship between the tooth tip width of the outer teeth 12 and the cogging torque when it is assumed that only the outer rotor 30 exists.

  It can be seen from FIG. 7 that the tooth tip width must be increased in order to minimize the cogging torque. In particular, in FIG. 7, the cogging torque decreases near 14.5 deg and near 19.3 deg. In such a case, since the length of the slot opening (the distance between adjacent teeth in the maximum width portion of the teeth) is reduced, the amount of the first mold resin 51 filled in the slot opening portion is also reduced. However, in this embodiment, the first mold resin 51 filled in the plurality of through-holes 18 penetrating in the axial direction in the stator yoke 14 is the same as the first mold resin 51 on the first surface 41 and the first mold resin 51. The first mold resin 51 on the second surface 42 is coupled. Thereby, even if the quantity of the 1st mold resin 51 with which a slot open part is filled decreases, the firm adhering force with respect to the stator core 11 of the 1st mold resin 51 is realizable.

  An outer rotor 30 is disposed facing the outer teeth 12 via a predetermined air gap. Similarly, the inner rotor 20 is disposed through a predetermined air gap so as to face the inner teeth 13.

  The outer rotor 30 includes an outer rotor yoke 31 and a plurality of outer permanent magnets 32 embedded in the outer rotor yoke 31. The outer rotor yoke 31 is laminated with magnetic steel sheets punched into a predetermined shape, and constitutes a magnetic circuit.

  Similarly, the inner rotor 20 includes an inner rotor yoke 21 and a plurality of inner permanent magnets 22 embedded in the inner rotor yoke 21. The inner rotor yoke 21 is laminated with electromagnetic steel plates punched into a predetermined shape, and constitutes a magnetic circuit. Each of the outer rotor 30 and the inner rotor 20 does not include a rotor frame. Therefore, the weight can be reduced and the number of manufacturing steps can be reduced. Furthermore, the volume of the frame can be covered with the second mold resin 52, and vibrations can be absorbed.

  The outer permanent magnet 32 and the inner permanent magnet 22 have been described as so-called magnet-embedded types that are embedded in the respective rotor yokes. . However, in order to utilize reluctance torque and achieve higher torque and higher output, either one needs to be a magnet embedded type.

  As described above, the outer rotor 30 and the inner rotor 20 are inserted into a resin molding die and integrally molded by the second molding resin 52. The motor shaft 61 is integrally connected. By performing a predetermined energization to the coil 15, the outer rotor 30 and the inner rotor 20 rotate integrally. By adopting an integral configuration of the outer rotor 30 and the inner rotor 20 as described above, the motor 5 can realize higher torque and higher output than a general inner rotor type motor or outer rotor type motor. Can do.

  FIG. 8 is a graph showing the relationship between the rotational position (electrical angle) of the rotor and the induced voltage. FIG. 8 shows the result of an experiment conducted with a rotor having a combination of the relationship between the number of slots S and the number of poles S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3). ing.

  From FIG. 8, if S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3), a substantially sine wave similar to that of the distributed winding type winding is obtained. It can be confirmed. Since the induced voltage waveform is sinusoidal, the noise and vibration of the motor 5 can be suppressed as in the case of the distributed winding method.

  Here, in the case of S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3), the reason for the substantially sine wave is the same as in the case of the distributed winding type winding. Will be described.

  FIG. 13 is a diagram schematically showing the state of the current flowing through the coil 15. The coil 15 is sequentially wound in the order of the U phase, the V phase, and the W phase. Further, a reverse current flows through the coils 15 wound in the adjacent slots. That is, when a current flows from the inner slot 17 to the outer slot 16 in a certain U-phase coil 15, a current flows from the outer slot 16 to the inner slot 17 in the adjacent V-phase coil 15. A current from the inner slot 17 toward the outer slot 16 flows through the W-phase coil 15 adjacent to the V-phase coil 15.

  Due to such a configuration, a reverse current flows through a certain U-phase coil 15 and the next U-phase coil 15. Therefore, a current indicated by a broken line flows in a pseudo manner. The broken line current flow is the same as the current flow in the distributed winding. Therefore, in the case of S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3), the current flow is the same as in the case of the distributed winding type winding. This is a substantially sine wave similar to the case of the distributed winding type winding.

  FIG. 9 is a diagram showing the relationship between the rotational position (electrical angle) of the rotor and the radial force. The solid line in FIG. 9 indicates the motor (a toroidal winding twin rotor type motor) according to this embodiment. On the other hand, the broken line indicates a distributed winding single rotor type motor.

  From FIG. 9, it can be seen that the toroidal winding type twin rotor type motor has a lower radial force than the distributed winding single rotor type motor. This is considered to be because the radial force can be reduced by canceling vibrations between the inner rotor and the outer rotor.

  Such an effect of reducing the radial force is particularly effective in the case of a direct drive type washing machine that rotates at a low speed of 10 rpm to 10 rpm during washing. This is because of the low speed rotation, the noise and vibration of the washing machine are likely to be affected by cogging.

  FIG. 10 is a diagram showing the relationship between the rotor rotational position (electrical angle) and cogging torque of a toroidal winding twin rotor type motor. In this figure, the thin broken line indicates the cogging torque due to the inner rotor 20, the thin solid line indicates the cogging torque due to the outer rotor 30, and the thick solid line at the center indicates the cogging torque of the motor 5 as a whole.

  In the motor 5 in this embodiment, the inner rotor 20 and the outer rotor 30 are configured to reverse the cogging torque phase of the inner rotor 20 and the cogging torque phase of the outer rotor 30. Further, the peak value of the cogging torque of the inner rotor 20 and the peak value of the cogging torque of the outer rotor 30 are made substantially the same. With such a configuration, as shown in FIG. 10, the cogging torque of the inner rotor 20 and the cogging torque of the outer rotor 30 can be canceled out, and the cogging torque of the entire motor 5 can be greatly reduced.

  FIG. 11 is a diagram illustrating the motor output density for each motor type. Here, the output density refers to the output per motor volume. In FIG. 11, A is an inner single rotor type motor, B is an outer single rotor type motor, C is a concentrated winding twin rotor type motor, and D is a toroidal winding twin rotor type motor in the present embodiment. The white portion indicates the output density by the inner rotor, and the hatched portion indicates the output density by the outer rotor.

  From FIG. 11, it can be seen that the output density of D is the maximum. Comparing D and A, since D has a smaller inner slot area than A, the output density of the inner rotor decreases. However, since D has an outer rotor, the overall power density exceeds A. From FIG. 11, it can be seen that D has a power density 1.9 times that of A.

  Further, when D is compared with B, since D has a smaller outer slot area than B, the output density of the outer rotor decreases. However, since D has an inner rotor, the overall power density exceeds B. From FIG. 11, it can be seen that D has a power density 1.5 times that of B.

  From this, it can be seen that the washing machine to which the motor D is applied can increase the washing capacity by 1.9 times compared to the washing machine to which the motor A is applied. It can also be seen that the washing machine to which the motor D is applied can increase the washing capacity by 1.5 times compared with the washing machine to which the motor B is applied. In other words, if D, A, and B have the same output, D can be reduced by 50% than the volume of A, and can be reduced by 35% than the volume of B.

  Further, comparing D and C, if the volume of the same rotor yoke is used, the amount of magnetic flux passing through the D rotor yoke exceeds the amount of magnetic flux passing through the C rotor yoke. For this reason, the overall output density of D exceeds C. From FIG. 11, it can be seen that D has a power density 1.4 times that of C.

  FIG. 12 is a diagram illustrating the relationship between the number of poles and the torque constant. In FIG. 12, the thick solid line shows the experimental result of a motor having a relationship of S: P = 3: 2N−1 (except when N is a multiple of 3). The thin broken line shows the experimental result of the motor having the conventional general relationship (S: P = 3: 2N). A thin solid line indicates the experimental result of a motor having a relationship other than the above. From FIG. 12, it can be seen that the motor having the relationship of S: P = 3: 2N−1 has an excellent torque constant particularly when the motor exceeds 20 poles. In particular, the combination of the number of slots S = 12, the number of poles P = 20 shown in this embodiment, that is, the relationship of S: P = 3: 5 is preferable.

  Since the motor described above includes a stator having a coil wound in a toroidal winding form and a twin rotor type rotor having an outer rotor and an inner rotor, the motor outputs a large torque while being small. And noise and vibration during driving can be reduced. Since the stator yoke, the outer slot, the inner slot, and the first mold resin that integrally mold the coil, and the second mold resin that integrally molds the outer rotor and the inner rotor, Compared to the case of molding using a frame, the weight can be reduced and the number of manufacturing steps can be reduced. Furthermore, the volume of the frame can be covered with the mold resin, and vibrations can be absorbed.

  Further, the stator yoke is formed with a plurality of through holes penetrating both end faces thereof, and the stator mold resin integrally forms the stator yoke, the outer slot, the inner slot, the coil and the through hole. The mold resins on both end faces of the two are connected by the mold resin filled in the through holes. Thereby, it can prevent that mold resin which coat | covers a stator peels from a stator.

  Furthermore, the number S of slots and the number P of poles have a relationship of S: P = 3: 2N−1, so that the induced voltage waveform becomes a sine wave, so that vibration and noise of the motor can be suppressed.

  A drum-type washing machine equipped with this motor is capable of increasing the washing capacity to the limit while being small. In addition, vibration and noise can be reduced, and quietness that can withstand night driving can be realized. Further, the structure in which the main part of the motor is covered with the mold resin can improve the waterproof / drip-proof performance and realize a highly reliable washing machine.

  The drum type washing machine according to the present invention is useful as a washing machine that outputs a large torque while being small, and reduces noise and vibration during driving.

  The present invention relates to a direct drive type drum-type washing machine including a rotating drum having a rotation center axis in a horizontal direction or an inclination direction and a motor for driving the rotating drum.

  In recent automatic washing machines, a direct drive drum washing machine with a drying function has become mainstream. Since the motor that drives the rotating drum of the washing machine directly drives the rotating drum without using a gear, low speed and high torque during washing (from 10 rpm to 100 rpm, 10 N · m or more) and high speed and low torque during dehydration ( 1000 rpm or more) must be realized at the same time. Further, since the speed is very low during washing, it is necessary to reduce the cogging torque of the motor that greatly affects the vibration and noise of the washing machine.

  As a technique for realizing such a motor that outputs low speed and high torque, a motor for a washing machine as described in Patent Document 1 and Patent Document 2 is known. The washing machine motor described in these patent documents includes a stator and a rotor disposed on the outer periphery of the stator. However, as described in Patent Document 1, in order to produce a large torque with a motor having only one stator and only one rotor, the amount of coils wound around the stator is increased, or the magnet strength of the rotor is increased. Have to do. For this reason, the problem that the volume became large as a whole occurred. Furthermore, the washing machine motor described in Patent Literature 1 includes a coil wound around the stator by a concentrated winding method. For this reason, radial force will become large compared with the motor provided with the coil wound by the distributed winding system. As a result, there has been a problem that noise and vibration during driving increase.

  In order to solve the above problem, a motor as described in Patent Document 2 has been proposed. The motor described in Patent Document 2 includes a hollow cylindrical stator having coils wound around teeth by a concentrated winding method, and an inner side arranged with a uniform gap with respect to the inner peripheral surface of the stator. And a rotor and an outer rotor disposed with a uniform gap with respect to the outer peripheral surface of the stator. The motor described in Patent Document 2 having such a configuration can use the force caused by the magnetic flux of the inner rotor and the force caused by the magnetic flux of the outer rotor. For this reason, it is possible to increase the output density and output a large torque while being small.

  However, the motor described in Patent Document 2 also includes a coil wound by the concentrated winding method, and thus the radial force increases. As a result, there has been a problem that vibration and noise during driving increase.

  As described above, the drum type washing machine equipped with the washing machine motor described in Patent Document 1 and Patent Document 2 has a problem that it is difficult to simultaneously realize high capacity, compactness, and low noise. Was.

JP 2007-089282 A JP-T-2005-521378

  The drum type washing machine of the present invention has the following configuration. A washing machine housing having an opening for taking in and out laundry, a rotating drum having a drum rotating shaft in a horizontal direction or an inclined direction with respect to the housing, and a motor for driving the rotating drum. The rotating shaft is a direct drive type washing machine directly connected to the motor shaft.

  The stator of the motor includes an annular stator yoke, a plurality of outer teeth projecting from the stator yoke in the outer circumferential direction, a plurality of inner teeth projecting from the stator yoke in the inner circumferential direction by the same number as the outer teeth, A plurality of outer slots configured between the teeth and a plurality of inner slots configured between the inner teeth are included. The stator further includes a coil connected in a three-phase star or delta shape to a stator yoke between the outer slot and the inner slot and wound in a toroidal winding form, a stator yoke, an outer slot, an inner slot, and a coil. And a first mold resin that is integrally molded.

  Further, the rotor of this motor is a twin type rotor, and is arranged with a predetermined air gap facing the outer teeth and a predetermined air gap facing the inner teeth. An inner rotor, a second molding resin that integrally molds the outer rotor and the inner rotor, and a motor shaft coupled to the outer rotor and the inner rotor.

  The drum type washing machine of the present invention with this configuration can increase the washing capacity to the limit while being small, reduce vibration and noise, and can realize quietness that can withstand night driving. . Further, the waterproof / drip-proof performance can be improved, and a highly reliable washing machine can be realized.

Sectional drawing of the drum type washing machine which concerns on embodiment of this invention The perspective view of the motor 5 of the drum type washing machine which concerns on embodiment of this invention Explanatory perspective view showing the stator and rotor of the motor 5 in the same manner as above The perspective view for explanation seen from a different direction Sectional view of motor 5 Sectional drawing which shows 6-6 cross section in FIG. Graph showing relationship between teeth tip width and cogging torque in motor 5 same as above The graph which shows the relationship between the rotational position (electrical angle) of a rotor in the motor 5 same as the above, and an induced voltage. The graph which shows the relationship between the rotational position (electrical angle) of a rotor and radial force in the motor 5 same as the above. The graph which shows the relationship between the rotor rotational position (electrical angle) and cogging torque in the motor 5 same as the above. The graph which shows the output density of the motor in the motor 5 same as the above for each motor type Graph showing the relationship between the number of poles and the torque constant in the motor 5 The figure which shows typically the mode of the electric current which flows into the coil 15 in the motor 5 same as the above.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a drum type washing machine according to an embodiment of the present invention.

  In the washing machine casing 1 of the drum type washing machine, a bottomed cylindrical water receiving tub 3 is disposed in a state of being inclined downward from the front side of the main body 1 toward the back side. The water receiving tub 3 supports the bottomed cylindrical rotary drum 2 on the inner side thereof so that the drum rotary shaft 4 is inclined downward from the front side to the back side of the washing machine casing 1. is doing.

  On the front side of the washing machine casing 1, an opening 1a for taking in and out the laundry is formed. The opening 1a is provided with a lid 9 made of a material such as glass for opening and closing the opening 1a.

  A motor shaft 61 of the motor 5 is directly connected to the outer side of the bottom of the water receiving tank 3 on the same axis as the drum rotating shaft 4 of the rotating drum 2. The motor 5 can control the rotation speed and the rotation direction of the rotary drum 2. In the motor 5, an attachment portion 60 (described later) formed on the outer peripheral portion of the motor 5 is fixed to the water receiving tank 3 by attachment means such as a screw (not shown).

  FIG. 2 is a perspective view of the motor 5 of the drum type washing machine according to the embodiment of the present invention. FIGS. 3 and 4 are exploded perspective views showing the stator 10 of the motor 5 and the twin rotor including the inner rotor 20 and the outer rotor 30. 3 and 4 are perspective views as seen from different directions.

  The motor 5 includes a stator 10, an inner rotor 20 that faces the inner diameter side of the stator 10, and an outer rotor 30 that faces the outer diameter side.

  The substantially entire surface of the stator 10 is covered with the first mold resin 51. Further, the inner rotor 20 and the outer rotor 30 are integrally formed with the second mold resin 52. Five attachment portions 60 are formed on the outer peripheral portion of the stator 10 so as to be arranged at uniform intervals in the rotation direction. The first mold resin 51 of the stator 10 and the second mold resin 52 of the rotor are each integrally formed by being inserted into a resin mold.

  A plurality of air holes 64 penetrating in the direction of the motor shaft 61 are formed in the second mold resin 52 of the rotor. The second mold resin 52 is provided with a plurality of convex portions 65 at portions facing the stator 10 and the motor shaft 61. For this reason, when the inner rotor 20 and the outer rotor 30 rotate, the heat generated from the stator 10 is agitated. Then, hot air in the rotational direction is generated between the stator 10, the inner rotor 20 and the outer rotor 30. This hot air flows out from the air hole 64 and heat in the motor 5 is released. Further, a plurality of ribs 62 are provided on the back side of the second mold resin 52. For this reason, the required intensity | strength can be ensured, reducing the amount of mold resin.

  5 is a sectional view of the motor 5, and FIG. 6 is a sectional view showing a section 6-6 in FIG. The stator core 11 constituting the stator 10 includes a substantially annular stator yoke 14, outer teeth 12 projecting from the stator yoke 14 in the outer circumferential direction, and inner teeth projecting from the stator yoke 14 in the same number as the outer teeth 12. 13 and. In the stator core 11, an outer slot 16 is formed between the outer teeth 12, and an inner slot 17 is formed between the inner teeth 13. The stator 10 further includes a plurality of coils 15 in a toroidal winding system connected in a three-phase star or delta shape, and wound around the stator yoke 14 between the outer slot 16 and the inner slot 17 in a concentrated winding system. Has been.

  Here, in the motor 5 according to this embodiment, the number of poles of the inner rotor 20 and the number of poles of the outer rotor 30 are both 20, and the number of slots is 12 slots. As described above, by using a combination of 20 poles and 12 slots, as will be described in detail later, it is possible to realize an effect equivalent to the distributed winding in the winding arrangement (see FIG. 8).

  As described above, the stator 10 is integrally formed with the first molding resin 51 after winding the coil 15. This is for fixing the coil 15 to the stator core 11 and for preventing moisture and drip. In particular, since the motor 5 is used in a washing machine, it is particularly important to improve moisture resistance and drip-proof performance. Further, in the case where the first molding resin 51 is integrally molded as described above, the molding resin 51 absorbs vibration, and the effect of reducing the vibration and noise of the entire washing machine can be expected.

  The stator yoke 14 of the stator core 11 is formed with a plurality of through holes 18 penetrating in the axial direction. When the coil 15 is integrally formed with the first molding resin 51, the outer slot 16, the inner slot 17, the first surface 41 of the stator yoke 14 (the upper side in FIG. 6), and the second surface 42 of the stator yoke 14. (The lower side in FIG. 6) and the through hole 18 are filled with the mold resin 51. With such a configuration, the first mold resin 51 on the first surface 41 of the stator yoke 14 and the first mold resin 51 on the second surface 42 are filled in the through hole 18. They are connected by the mold resin 51. Therefore, even if the first mold resin 51 on the first surface 41 and the first mold resin 51 on the second surface 42 are formed to be thin for motor miniaturization, the through hole 18 is filled. Since the mold resin 51 is connected, peeling can be prevented. Note that the mounting portion 60 is formed on the second surface 42 by the first mold resin 51.

  The through hole 18 is provided at the intersection of a straight line 71 connecting the center of the outer teeth 12 in the rotational direction and the center of the inner teeth 13 in the rotational direction and passing through the center of rotation and the central arc 72 of the stator yoke 14. The cross-sectional shape of the through hole 18 is preferably circular or elliptical. This is because the fluidity of the mold resin material is improved with this shape.

  Further, the through hole 18 preferably has a radial length of 0.5 ± 10% with respect to the radial length of the stator yoke 14. This is because if the value is larger than this value, the stator yoke 14 may be magnetically saturated and the motor torque may be reduced. If the value is smaller than this value, the fluidity of the mold resin is deteriorated during molding, and the strength is increased. It is because it falls. The cross-sectional shape of the through-hole 18 is not limited to a circle or an ellipse, and a quadrangle, a rectangle, a triangle, or the like can be appropriately employed.

  The first mold resin 51 and the second mold resin 52 are preferably unsaturated polyester resins containing a filler. This is because the fluidity during molding and the strength after molding are excellent.

  FIG. 7 is a graph showing the relationship between the tooth tip width and the cogging torque. The broken line in the figure shows the relationship between the tooth tip width of the inner teeth 13 and the cogging torque when it is assumed that only the inner rotor 20 exists. The solid line indicates the relationship between the tooth tip width of the outer teeth 12 and the cogging torque when it is assumed that only the outer rotor 30 exists.

  It can be seen from FIG. 7 that the tooth tip width must be increased in order to minimize the cogging torque. In particular, in FIG. 7, the cogging torque decreases near 14.5 deg and near 19.3 deg. In such a case, since the length of the slot opening (the distance between adjacent teeth in the maximum width portion of the teeth) is reduced, the amount of the first mold resin 51 filled in the slot opening portion is also reduced. However, in this embodiment, the first mold resin 51 filled in the plurality of through-holes 18 penetrating in the axial direction in the stator yoke 14 is the same as the first mold resin 51 on the first surface 41 and the first mold resin 51. The first mold resin 51 on the second surface 42 is coupled. Thereby, even if the quantity of the 1st mold resin 51 with which a slot open part is filled decreases, the firm adhering force with respect to the stator core 11 of the 1st mold resin 51 is realizable.

  An outer rotor 30 is disposed facing the outer teeth 12 via a predetermined air gap. Similarly, the inner rotor 20 is disposed through a predetermined air gap so as to face the inner teeth 13.

  The outer rotor 30 includes an outer rotor yoke 31 and a plurality of outer permanent magnets 32 embedded in the outer rotor yoke 31. The outer rotor yoke 31 is laminated with magnetic steel sheets punched into a predetermined shape, and constitutes a magnetic circuit.

  Similarly, the inner rotor 20 includes an inner rotor yoke 21 and a plurality of inner permanent magnets 22 embedded in the inner rotor yoke 21. The inner rotor yoke 21 is laminated with electromagnetic steel plates punched into a predetermined shape, and constitutes a magnetic circuit. Each of the outer rotor 30 and the inner rotor 20 does not include a rotor frame. Therefore, the weight can be reduced and the number of manufacturing steps can be reduced. Furthermore, the volume of the frame can be covered with the second mold resin 52, and vibrations can be absorbed.

  The outer permanent magnet 32 and the inner permanent magnet 22 have been described as so-called magnet-embedded types that are embedded in the respective rotor yokes. . However, in order to utilize reluctance torque and achieve higher torque and higher output, either one needs to be a magnet embedded type.

  As described above, the outer rotor 30 and the inner rotor 20 are inserted into a resin molding die and integrally molded by the second molding resin 52. The motor shaft 61 is integrally connected. By performing a predetermined energization to the coil 15, the outer rotor 30 and the inner rotor 20 rotate integrally. By adopting an integral configuration of the outer rotor 30 and the inner rotor 20 as described above, the motor 5 can realize higher torque and higher output than a general inner rotor type motor or outer rotor type motor. Can do.

  FIG. 8 is a graph showing the relationship between the rotational position (electrical angle) of the rotor and the induced voltage. FIG. 8 shows the result of an experiment conducted with a rotor having a combination of the relationship between the number of slots S and the number of poles S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3). ing.

  From FIG. 8, if S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3), a substantially sine wave similar to that of the distributed winding type winding is obtained. It can be confirmed. Since the induced voltage waveform is sinusoidal, the noise and vibration of the motor 5 can be suppressed as in the case of the distributed winding method.

  Here, in the case of S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3), the reason for the substantially sine wave is the same as in the case of the distributed winding type winding. Will be described.

  FIG. 13 is a diagram schematically showing the state of the current flowing through the coil 15. The coil 15 is sequentially wound in the order of the U phase, the V phase, and the W phase. Further, a reverse current flows through the coils 15 wound in the adjacent slots. That is, when a current flows from the inner slot 17 to the outer slot 16 in a certain U-phase coil 15, a current flows from the outer slot 16 to the inner slot 17 in the adjacent V-phase coil 15. A current from the inner slot 17 toward the outer slot 16 flows through the W-phase coil 15 adjacent to the V-phase coil 15.

  Due to such a configuration, a reverse current flows through a certain U-phase coil 15 and the next U-phase coil 15. Therefore, a current indicated by a broken line flows in a pseudo manner. The broken line current flow is the same as the current flow in the distributed winding. Therefore, in the case of S: P = 3: 2N−1 (except when 2N−1 is a multiple of 3), the current flow is the same as in the case of the distributed winding type winding. This is a substantially sine wave similar to the case of the distributed winding type winding.

  FIG. 9 is a diagram showing the relationship between the rotational position (electrical angle) of the rotor and the radial force. The solid line in FIG. 9 indicates the motor (a toroidal winding twin rotor type motor) according to this embodiment. On the other hand, the broken line indicates a distributed winding single rotor type motor.

  From FIG. 9, it can be seen that the toroidal winding type twin rotor type motor has a lower radial force than the distributed winding single rotor type motor. This is considered to be because the radial force can be reduced by canceling vibrations between the inner rotor and the outer rotor.

  Such an effect of reducing the radial force is particularly effective in the case of a direct drive type washing machine that rotates at a low speed of 10 rpm to 10 rpm during washing. This is because of the low speed rotation, the noise and vibration of the washing machine are likely to be affected by cogging.

  FIG. 10 is a diagram showing the relationship between the rotor rotational position (electrical angle) and cogging torque of a toroidal winding twin rotor type motor. In this figure, the thin broken line indicates the cogging torque due to the inner rotor 20, the thin solid line indicates the cogging torque due to the outer rotor 30, and the thick solid line at the center indicates the cogging torque of the motor 5 as a whole.

  In the motor 5 in this embodiment, the inner rotor 20 and the outer rotor 30 are configured to reverse the cogging torque phase of the inner rotor 20 and the cogging torque phase of the outer rotor 30. Further, the peak value of the cogging torque of the inner rotor 20 and the peak value of the cogging torque of the outer rotor 30 are made substantially the same. With such a configuration, as shown in FIG. 10, the cogging torque of the inner rotor 20 and the cogging torque of the outer rotor 30 can be canceled out, and the cogging torque of the entire motor 5 can be greatly reduced.

  FIG. 11 is a diagram illustrating the motor output density for each motor type. Here, the output density refers to the output per motor volume. In FIG. 11, A is an inner single rotor type motor, B is an outer single rotor type motor, C is a concentrated winding twin rotor type motor, and D is a toroidal winding twin rotor type motor in the present embodiment. The white portion indicates the output density by the inner rotor, and the hatched portion indicates the output density by the outer rotor.

  From FIG. 11, it can be seen that the output density of D is the maximum. Comparing D and A, since D has a smaller inner slot area than A, the output density of the inner rotor decreases. However, since D has an outer rotor, the overall power density exceeds A. From FIG. 11, it can be seen that D has a power density 1.9 times that of A.

  Further, when D is compared with B, since D has a smaller outer slot area than B, the output density of the outer rotor decreases. However, since D has an inner rotor, the overall power density exceeds B. From FIG. 11, it can be seen that D has a power density 1.5 times that of B.

  From this, it can be seen that the washing machine to which the motor D is applied can increase the washing capacity by 1.9 times compared to the washing machine to which the motor A is applied. It can also be seen that the washing machine to which the motor D is applied can increase the washing capacity by 1.5 times compared with the washing machine to which the motor B is applied. In other words, if D, A, and B have the same output, D can be reduced by 50% than the volume of A, and can be reduced by 35% than the volume of B.

  Further, comparing D and C, if the volume of the same rotor yoke is used, the amount of magnetic flux passing through the D rotor yoke exceeds the amount of magnetic flux passing through the C rotor yoke. For this reason, the overall output density of D exceeds C. From FIG. 11, it can be seen that D has a power density 1.4 times that of C.

  FIG. 12 is a diagram illustrating the relationship between the number of poles and the torque constant. In FIG. 12, the thick solid line shows the experimental result of a motor having a relationship of S: P = 3: 2N−1 (except when N is a multiple of 3). The thin broken line shows the experimental result of the motor having the conventional general relationship (S: P = 3: 2N). A thin solid line indicates the experimental result of a motor having a relationship other than the above. From FIG. 12, it can be seen that the motor having the relationship of S: P = 3: 2N−1 has an excellent torque constant particularly when the motor exceeds 20 poles. In particular, the combination of the number of slots S = 12, the number of poles P = 20 shown in this embodiment, that is, the relationship of S: P = 3: 5 is preferable.

  Since the motor described above includes a stator having a coil wound in a toroidal winding form and a twin rotor type rotor having an outer rotor and an inner rotor, the motor outputs a large torque while being small. And noise and vibration during driving can be reduced. Since the stator yoke, the outer slot, the inner slot, and the first mold resin that integrally mold the coil, and the second mold resin that integrally molds the outer rotor and the inner rotor, Compared to the case of molding using a frame, the weight can be reduced and the number of manufacturing steps can be reduced. Furthermore, the volume of the frame can be covered with the mold resin, and vibrations can be absorbed.

  Further, the stator yoke is formed with a plurality of through holes penetrating both end faces thereof, and the stator mold resin integrally forms the stator yoke, the outer slot, the inner slot, the coil and the through hole. The mold resins on both end faces of the two are connected by the mold resin filled in the through holes. Thereby, it can prevent that mold resin which coat | covers a stator peels from a stator.

  Furthermore, the number S of slots and the number P of poles have a relationship of S: P = 3: 2N−1, so that the induced voltage waveform becomes a sine wave, so that vibration and noise of the motor can be suppressed.

  A drum-type washing machine equipped with this motor is capable of increasing the washing capacity to the limit while being small. In addition, vibration and noise can be reduced, and quietness that can withstand night driving can be realized. Further, the structure in which the main part of the motor is covered with the mold resin can improve the waterproof / drip-proof performance and realize a highly reliable washing machine.

  The drum type washing machine according to the present invention is useful as a washing machine that outputs a large torque while being small, and reduces noise and vibration during driving.

DESCRIPTION OF SYMBOLS 1 Washing machine housing | casing 1a Opening part 2 Rotating drum 3 Water receiving tank 4 Drum rotating shaft 5 Motor 9 Lid 10 Stator 11 Stator core 12 Outer teeth 13 Inner teeth 14 Stator yoke 15 Coil 16 Outer slot 17 Inner slot 18 Through hole 20 Inner rotor 21 inner rotor yoke 22 inner permanent magnet 30 outer rotor 31 outer rotor yoke 32 outer permanent magnet 41 first surface 42 second surface 51 first mold resin 52 second mold resin 60 mounting portion 61 motor shaft 62 rib 64 air hole 65 Projection 71 Straight line connecting the center of rotation of the outer teeth and the center of rotation of the inner teeth 72 Center arc of the stator yoke

Claims (12)

A washing machine housing having an opening for taking in and out laundry, a rotating drum having a drum rotating shaft in a horizontal direction or an inclined direction with respect to the washing machine housing, and a motor for driving the rotating drum. In a drum-type washing machine
The drum rotation shaft is a direct drive type washing machine directly connected to the motor shaft of the motor,
The motor includes an annular stator yoke, a plurality of outer teeth projecting from the stator yoke in the outer circumferential direction, a plurality of inner teeth projecting from the stator yoke in the inner circumferential direction in the same number as the outer teeth, A plurality of outer slots formed between the teeth, a plurality of inner slots formed between the inner teeth, and the stator yoke between the outer slots and the inner slots are connected in a three-phase star or delta shape. A stator including a coil wound in a toroidal winding form, and a first mold resin that integrally molds the stator yoke, the outer slot, the inner slot, and the coil;
An outer rotor disposed opposite to the outer teeth via a predetermined air gap, an inner rotor disposed opposite to the inner teeth via a predetermined air gap, the outer rotor and the inner side A drum type washing machine comprising: a twin type rotor including: a second mold resin that integrally molds a rotor; and the outer rotor and the motor shaft coupled to the inner rotor. . The drum-type washing machine according to claim 1, further comprising a bottomed cylindrical water receiving tub on an outer peripheral side of the rotating drum, wherein the motor is fixed to a bottom portion of the water receiving tub. The drum-type washing machine according to claim 2, wherein the first mold resin has a plurality of attachment portions, and the attachment portions are fixed to the water receiving tub. The stator yoke has a plurality of through holes penetrating in the axial direction, and the first molding resin integrally forms the stator yoke, the outer slot, the inner slot, the coil, and the through hole. The drum type washing machine according to claim 1, wherein the drum type washing machine is provided. 5. The drum according to claim 4, wherein the through hole is formed at an intersection of a straight line connecting the rotation center of the outer teeth and the rotation center of the inner teeth and a central arc of the stator yoke. Type washing machine. The drum-type washing machine according to claim 4, wherein the through hole has a circular or oval cross section. The drum-type washing machine according to claim 1, wherein the second mold resin has a plurality of air holes penetrating in the direction of the motor shaft. 2. The drum type washing machine according to claim 1, wherein the second mold resin has a plurality of convex portions at a portion facing the stator in the direction of the motor shaft. The drum-type washing machine according to claim 1, wherein the second mold resin has a plurality of ribs on the back side. The number of the outer slots and the number of the inner slots are the same number S,
The outer rotor includes an outer rotor yoke and an outer permanent magnet having a pole number P,
The inner rotor includes an inner rotor yoke and an inner permanent magnet having P poles,
If the integer N is greater than or equal to 1 and 2N-1 is a multiple of 3,
The drum type washing machine according to claim 1, wherein the number S of slots and the number P of poles have a relationship of S: P = 3: 2N-1. 11. The drum type washing machine according to claim 10, wherein the number of slots S and the number of poles P are in a relationship of S: P = 3: 5. The drum type washing machine according to claim 10, wherein at least one of the outer permanent magnet and the inner permanent magnet is embedded in the outer rotor yoke or the inner rotor yoke.

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