JP5209557B2 - Permanent magnet motor and washing machine - Google Patents

Description

  The present invention relates to a permanent magnet motor provided with a large number of permanent magnets in a rotor and a washing machine using the permanent magnet motor.

  For example, in a permanent magnet motor used in a drum-type washing machine, a stator coil of a stator is chained according to low-speed rotation (washing and rinsing) and high-speed rotation (during dehydration) of a drum which is a load of a washing machine to be driven. It is desired to properly adjust the magnetic flux amount (induced voltage) of the permanent magnets that intersect.

  However, the permanent magnet provided in the rotor of the permanent magnet motor is generally constituted by one type, and therefore the amount of magnetic flux of the permanent magnet is always constant. In this case, for example, if the rotor is composed only of a permanent magnet having a large coercive force, the induced voltage due to the permanent magnet during high-speed rotation (during dehydration) becomes extremely high, which may lead to dielectric breakdown of electronic components. On the other hand, if the rotor is composed only of permanent magnets having a small coercive force, the output during low-speed rotation (washing and rinsing) will decrease.

  Therefore, for example, in the permanent magnet motor described in Patent Document 1, two types of permanent magnets having different coercive forces are arranged inside the rotor, and among them, the magnetization state of the low coercive force permanent magnet is changed to an external magnetic field (stator). The amount of magnetic flux of the permanent magnet is adjusted by demagnetizing or magnetizing with a magnetic field generated by the current flowing through the coil.

JP 2006-280195 A

  In the permanent magnet motor described in Patent Document 1, both a permanent magnet having a large coercive force and a permanent magnet having a small coercive force are disposed in a portion constituting one magnetic pole inside the rotor. That is, since one magnetic pole is formed by a plurality of types of permanent magnets, the number of permanent magnets must be extremely increased and the volume of each permanent magnet must be reduced, resulting in a complicated structure.

  In order to solve such a problem, a permanent magnet motor having a simplified structure in which two types of permanent magnets having different coercive forces are alternately arranged on a rotor, one type per magnetic pole, can be considered. However, the permanent magnet motor having this configuration is not publicly known. However, in a permanent magnet motor having a configuration in which two types of permanent magnets having different coercive forces are alternately arranged per magnetic pole, the composition ratio of a magnet having a large coercive force and a magnet having a small coercive force is 1: 1. . Therefore, there arises a new problem that the total magnetic flux amount of the entire rotor is remarkably lowered as compared with a case where only the permanent magnet having a large coercive force is configured.

  Therefore, a permanent magnet motor as shown in FIG. 7 can be considered. In FIG. 7, the stator 101 and the rotor 102 of the permanent magnet motor 100 are shown expanded linearly. That is, the stator 101 has a stator coil (not shown) of each phase wound around an annular stator core formed by combining six divided cores 103 each having, for example, six magnetic pole teeth 103a in the circumferential direction. Each magnetic pole tooth 103a corresponds to the U, V, and W phases sequentially.

  The rotor 102 is configured by inserting a permanent magnet into an annular rotor core formed by combining a plurality of pairs, for example, three pairs of divided cores 104A and 104B having a plurality of, for example, eight magnet insertion holes 104a in the circumferential direction. ing. In this case, the permanent magnet is selected from two types of permanent magnets 105a and 105b having different coercive forces so as to be one type of one magnetic pole. For example, one of the pair of split cores 104A and 104B has eight magnet insertion holes 104a in one split core 104A, one low coercive permanent magnet 105a from the left side, and one high coercive force. Permanent magnet 1105b, one low coercivity permanent magnet 105a and five high coercivity permanent magnets 1105b are inserted, and a total of eight are inserted into the eight magnet insertion holes 104a of the other split core 104B. The high coercive force permanent magnet 1105b is inserted. The permanent magnet motor shown in FIG. 7 is a reference example and is not known.

  According to such a configuration, there are two low-coercivity permanent magnets 105a in the divided core 104A and six rotors 102 as a whole, so that the total magnetic flux amount as a whole of the rotor 102 can be sufficiently secured. In the split core 104A, a low coercivity permanent magnet 105a ([small N]) and a high coercivity permanent magnet 105b (with respect to the U, V, W phase magnetic pole teeth 103a on one side (left side) of the stator 101 ( “Large S”) and a low coercivity permanent magnet 105a (“Small N”) are arranged. As the rotor 102 rotates, the magnetic fluxes of the low coercivity permanent magnet 105a ([small N]), the high coercivity permanent magnet 105b (“large S”), and the low coercivity permanent magnet 105a (“small N”). As a result, an induced voltage related to torque is generated in the U, V, and W phase coils of the magnetic pole teeth 103a of the stator 101. For example, if the amount of magnetic flux of the “small N” permanent magnet 105 a is ½ of the amount of magnetic flux of the “large S” permanent magnet 105 b, one induced voltage and one induced by the two “small N” permanent magnets 105 a are used. The induced voltage caused by the “large S” permanent magnet 105b is balanced and magnetically balanced.

  However, in the above configuration, since three pairs of the split cores 104A and 104B are combined, the rotor 102 as a whole is magnetically balanced, but the total amount of magnetic flux between the pair of split cores 104A and 104B. As a result, the amount of magnetic flux becomes non-uniform between the pair of split cores 104A and 104B, and torque ripple and cogging torque increase, causing noise and vibration.

  The present invention has been made in view of the above circumstances, and its purpose is to adjust the amount of magnetic flux of a permanent magnet according to the load to be driven, from two types of permanent magnets having different coercive forces to one type per magnetic pole. The permanent magnet motor capable of suppressing the generation of torque ripple and cogging torque even if the ratio of the permanent magnet having a small coercive force is reduced. It is providing the washing machine provided with the magnet motor.

  A permanent magnet motor of the present invention includes a permanent magnet that forms a large number of magnetic poles in a rotor core of a rotor, and includes a stator having magnetic pole teeth corresponding to a stator coil of each phase, and the rotor core includes a plurality of magnet insertion holes in a circumferential direction. A plurality of split cores having a plurality of split cores are combined, and permanent magnets selected from two types of permanent magnets having different coercive forces to be one type per pole are inserted into the magnet insertion holes of the split cores, In the split core, the number of low coercive permanent magnets is set to be smaller than the number of high coercive permanent magnets, and the total magnetic flux of the plurality of permanent magnets is substantially between adjacent split cores. It is set so that it may become equal.

  A washing machine according to the present invention is characterized in that the washing machine load is rotationally driven by the permanent magnet motor according to any one of claims 1 to 4.

According to the permanent magnet motor of the present invention, even if two types of permanent magnets having different coercive forces (permanent magnets having different residual magnetic flux densities) are arranged at different ratios, the occurrence of non-uniform magnetic flux can be suppressed. Therefore, it is possible to suppress the occurrence of torque ripple and cogging torque due to the difference in the total magnetic flux amount between adjacent divided cores.

  According to the washing machine of the present invention, the amount of magnetic flux of the permanent magnet can be adjusted efficiently according to the operating state such as washing, rinsing, and dehydration.

The perspective view of the permanent magnet motor which shows the 1st Example of this invention Enlarged perspective view of the main part Action explanatory diagram showing a part of the stator and rotor expanded linearly The schematic structure of a drum type washing machine is shown, (a) is a longitudinal side view, (b) is a longitudinal rear view. FIG. 3 equivalent view showing a second embodiment of the present invention. FIG. 3 equivalent view showing a third embodiment of the present invention. 3 equivalent diagram showing a reference example

(First embodiment)
A first embodiment in which the present invention is applied to a drum type washing machine will be described below with reference to FIGS.

  First, in FIG. 4, a water tank 2 is disposed in the outer box 1 of the drum type washing machine. The water tank 2 has a substantially cylindrical shape in which a rear surface portion 2a (right end surface portion in FIG. 4A) as one end portion is closed, and is elastically supported by a damper mechanism (not shown) in a state where the axial direction is substantially horizontal. ing. In the water tank 2, the drum 3 which comprises a rotation tank is arrange | positioned rotatably. The drum 3 also has a substantially cylindrical shape in which the rear surface portion 3a (the right end surface portion in FIG. 4A), which is one end portion, is closed, and is disposed in a state where the axial direction is substantially horizontal. A number of holes (not shown) are formed in the peripheral wall of the drum 3. Although not shown, the front portion 1a of the outer box 1 is provided with a door for opening and closing the laundry entrance, and an opening is formed on the front side of the water tub 2 and the drum 3 so that the laundry can be washed. The drum 3 is taken in and out through the material entrance.

  A permanent magnet motor (hereinafter simply referred to as “data”) 4 that rotationally drives the drum 3 is disposed on the back surface of the rear surface portion 2 a of the water tank 2. In this case, the motor 4 is formed of an outer rotor type brushless DC motor, and a shaft 6 connected to the rotor 5 is connected to the rear portion of the drum 3. Therefore, a direct drive system in which the drum 3 is directly rotated by the motor 4 is employed. The drum 3 corresponds to a washing machine load (load) that is rotationally driven by the motor 4.

  The motor 4 will be described with reference to FIGS. The stator 7 of the motor 4 includes a stator core 9 having a large number of, for example, 36 magnetic pole teeth 8 on the outer peripheral portion, a stator coil 10 wound around each magnetic pole tooth 8, and a synthetic resin mounting portion 11. It is attached to the rear surface portion 2a of the water tank 2 through the attachment portion 11 in a fixed state. In this case, as shown in FIG. 3, the stator core 9 has six split cores 9A as divided into six parts, and engaging projections 9a formed at one end part. The joint recesses 9b are connected to each other by being inserted and engaged with each other. Accordingly, one divided core 9A has six magnetic pole teeth 8, and three adjacent magnetic pole teeth 8 correspond to the three-phase U, V, and W phases.

  The rotor 5 is formed of a shallow container-shaped magnetic body frame 12 having an annular wall 12 a on the outer periphery, an annular rotor core 13 disposed on the inner periphery of the annular wall 12 a, and the rotor core 13. The permanent magnets 14 and 15 having different coercive forces inserted into the numerous magnet insertion holes 17 are provided, and the shaft 6 is attached to the shaft mounting portion 16 provided at the center of the frame 12. Connected. In this case, the low (small) coercive force permanent magnet 14 is composed of, for example, an alnico magnet having a low coercive force (the coercive force of the alnico magnet is 350 kA / m or less). The permanent magnet 15 having a high (large) coercive force is constituted by, for example, a neodymium magnet (the coercive force of the neodymium magnet is 700 kA / m or more) that has a high coercive force.

  As shown in FIG. 3, the rotor core 13 is configured by combining three pairs of adjacent pairs of divided cores 13A and 13B. The split cores 13A and 13B are configured by inserting and arranging eight permanent magnets 14 or 15 in eight magnet insertion holes 17 so that N and S poles are alternately formed. One of the divided cores 13A has a low coercivity permanent magnet 14 with respect to the arrangement of U, V, W, U, V, and W phase magnetic pole teeth 8 from one side (left side) of the divided core 9A. ("Small N"), high coercivity permanent magnet 15 ("large S"), high coercivity permanent magnet 15 ("large N"), high coercivity permanent magnet 15 ("large S"), high coercivity permanent magnet Magnet 15 (“large N”, high coercivity permanent magnet 15 (“large S”), high coercivity permanent magnet 15 (“large N”) and high coercivity permanent magnet 15 (“large S”) Has been placed.

  In the other split core 13B, the high coercive force permanent magnet 15 ("large N", high coercive force) with respect to the arrangement of U, V, W, U, V and W phases from one side (left side) of the split core 9A. Permanent magnet 15 ("large S"), low coercivity permanent magnet 14 ("small N")), high coercivity permanent magnet 15 ("large S"), high coercivity permanent magnet 15 ("large N") The high coercivity permanent magnet 15 (“Large S”), the high coercivity permanent magnet 15 (“Large N”), and the high coercivity permanent magnet 15 (“Large S”) are arranged to respond.

  As described above, the pair of split cores 13A and 13B includes one low-coercivity permanent magnet 14 and seven high-coercivity permanent magnets 15, and the total magnetic flux is substantially equal. However, in the pair of split cores 13A and 13B, in one split core 13A, the low coercivity permanent magnet 14 is positioned first on the left side, whereas in the other split core 13B, the low core The arrangement order of the permanent magnets 14 and 15 is set to be different so that the magnetic permanent magnet 14 is located third from the left side.

  On the other hand, as shown in FIGS. 2 and 3, in one pair of split cores 13A and 13B, rectangular engagement convex portions 13a as engagement portions are formed at both ends of one split core 13A. At both ends of the other split core 13B, rectangular engaging recesses 13b are formed as engaged portions. Accordingly, in the split cores 13A and 13B, if the split cores 13A and 13B are paired, the engaging convex portion 13a as the engaging portion of one split core 13A is the engaged portion of the other split core 13B. It is possible to engage with the engaging recess 13b.

  However, when combining the split cores 13A and 13A that do not form a pair, the engaging convex portion 13a as the engaging portion of one split core 13A becomes the engaging convex portion as the engaged portion of the other split core 13A. It is impossible to engage with the portion 13a. Similarly, when trying to combine the split cores 13B and 13B that do not form a pair, the engagement recess 13b as the engagement portion of one split core 13B becomes the engagement recess as the engaged portion of the other split core 13B. It is impossible to engage 13b.

  In the motor 4, 12 U-phase stator coils 10 wound around the 12 magnetic pole teeth 8 of the rotor core 13 are connected in series, and 12 V-phases wound around the 12 magnetic pole teeth 8. The stator coils 10 are connected in series, and the 12 W-phase stator coils 10 wound around the 12 magnetic pole teeth 8 are connected in series so that these series circuits are star-connected. It has become. Although not shown, the motor 4 is controlled via an inverter circuit by a control device including a microcomputer as control means. The control device has a function of controlling a washing operation including a washing process, a rinsing process, and a dehydrating process, which will be described later.

The operation of this embodiment will be described.
When starting the washing operation, the control device first performs a washing process. In the washing process, a water supply valve (not shown), which is a load on the washing machine, is opened to supply water in the water tank 2 and in the drum 3 for storage. Next, in a state where the detergent is put into the water tank 2, the drum 3 is rotated forward and reverse by the motor 4 at a low rotation speed of, for example, 50 to 60 rpm. Thereby, washing in which the laundry stored in the drum 3 is washed is performed. After washing for a predetermined time, in the state where the drum 3 is stopped, a drain valve (not shown) which is a washing machine load connected to the discharge port of the water tank 2 is opened, so that the inside of the water tank 2 (in the drum 3 ) Drain the water out of the machine.

  Next, the control device performs intermediate dehydration in the washing process. In this intermediate dehydration, the drum 3 is rotated in one direction by the motor 4 at a high speed of, for example, 1500 rpm. Thereby, the laundry in the drum 3 is centrifugally dehydrated. Moisture discharged from the laundry is discharged from the outlet to the outside of the machine.

  When the intermediate dehydration is completed, the control device proceeds to the rinsing process. In the rinsing step, first, water is supplied again in a state where the rotation of the drum 3 is stopped, and water is supplied into the water tank 2 and thus into the drum 3 to be stored. Next, rinsing is performed. Rinsing has the same control as washing except that no detergent is used. That is, the drum 3 is forwardly and reversely rotated at a low rotational speed of, for example, 50 to 60 rpm by the motor 4, thereby rinsing the laundry in the drum 3 for a predetermined time, and then draining the same as described above. Thereafter, the same water supply, rinsing, and draining are repeated a plurality of times to complete the rinsing process.

  Next, the control device performs a dehydration process. In the dehydration process, the drum 3 is rotated in one direction by the motor 4 at a high speed of, for example, 1000 rpm. Thereby, the laundry in the drum 3 is centrifugally dehydrated. Moisture discharged from the laundry is discharged from the outlet to the outside of the machine. When the above dehydration is performed for a predetermined time, the dehydration process is completed, and the washing operation ends.

  Here, in the washing process described above, the rotation speed of the drum 3 (motor 4) is low (50 to 60 rpm), and the motor 4 requires low speed rotation and high torque. In the previous water supply, the control device increases the magnetism so as to increase the magnetic flux of the permanent magnet 14 of the motor 4.

  Specifically, by applying a voltage of, for example, +500 V to the stator coil 10, the magnetic flux of the permanent magnet 14 is increased to the maximum, and the magnetic flux is maintained even when the application of the voltage is canceled. As a result, the magnetic flux of the entire rotor 5 acting on the stator 7 increases. In this state, the motor 4 can exhibit high torque by rotating the drum 3 at a low speed to perform washing in the washing process. During this washing process, since the normal operating voltage to the stator coil 10 is in the range of about ± 200 V, the magnetic flux does not change even with the low coercivity permanent magnet 14.

  Next, in the intermediate dewatering process of the washing process, the rotation speed of the drum 3 (motor 4) is high (1500 rpm), and the motor 4 requires low torque and high speed rotation. The control device performs demagnetization to reduce the magnetic flux of the permanent magnet 14.

  Specifically, by applying a voltage slightly higher than −500 V, for example, to the stator coil 10, the magnetic flux of the permanent magnet 14 is lowered to nearly 0 (zero), and the magnetic flux is retained even when the voltage application is canceled. So that Thereby, the magnetic flux as a whole of the rotor 5 acting on the stator 7 is reduced. In this state, by rotating the drum 3 at a high speed by the motor 4 and performing intermediate dehydration, the motor 4 is suitable for low torque and high speed rotation. Even during this intermediate dehydration, the normal operating voltage to the stator coil 10 is in the range of about ± 200 V, so that the magnetic flux does not change even with the low coercivity permanent magnet 14.

  Next, in the rinsing process, as in the washing process, the rotation speed of the drum 3 (motor 4) is low (50 to 60 rpm), and the motor 4 requires low speed rotation and high torque. In the water supply before rinsing, in order to increase the magnetic flux of the permanent magnet 14, the same magnetization as described above is performed. Rinsing is performed in the state of increasing the magnetism.

  In the dehydration process, the rotational speed of the drum 3 (motor 4) is high (1000 rpm) and the motor 4 requires low torque and high-speed rotation, as in the intermediate dehydration process of the washing process. In the drainage of the rinsing process before the process, the same demagnetization as described above is performed to reduce the magnetic flux of the permanent magnet 14. The dehydration process is performed in such a demagnetized state.

According to the first embodiment described above, the following operational effects can be obtained.
The divided cores 13A and 13B in the rotor 5 are configured to have a low-coercivity permanent magnet 14 that can be easily changed and a permanent magnet 15 having a higher coercivity than the permanent magnet 14, and in the washing process and the rinsing process, The permanent magnet 14 is magnetized so that the magnetic flux of the rotor 5 acting on the stator 7 is increased, and the magnetic flux of the rotor 5 acting on the stator 7 is washed in the dehydration stroke (the same as the intermediate dehydration in the washing stroke). The permanent magnet 14 is magnetized so as to be smaller than in the stroke and rinse stroke. Thereby, in the washing process and the rinsing process, the magnetic flux of the rotor 5 acting on the stator 7 can be increased, and the motor 4 for driving the washing machine load (drum 3) has a low speed necessary for the washing process and the rinsing process. Rotation and high torque can be obtained. In the dewatering stroke, the magnetic flux of the rotor 5 acting on the stator 7 is reduced as compared with that in the washing stroke and the rinsing stroke, so that the motor 4 that drives the load (drum 3) has a low torque necessary for the dewatering stroke. The performance suitable for high-speed rotation can be demonstrated.

  Since the adjacent pair of split cores 13A and 13B each have one low coercivity permanent magnet 14 and seven high coercivity permanent magnets 15, the total magnetic flux amounts are substantially equal, and the adjacent split cores 13A are adjacent to each other. , 13B is good, and the magnetic balance of the entire rotor 5 is therefore good.

  Further, in one pair of adjacent split cores 13A and 13B, in one split core 13A, the low coercivity permanent magnet 14 is positioned first from the left side, and in the other split core 13B, the third lowest level from the left side is the lowest. A coercive permanent magnet 14 is located. Thereby, according to the rotation of the rotor 5, for example, an induced voltage is generated in the U, V, or W phase coil 10 of the magnetic pole teeth 8 of the split core 9A on one side by the permanent magnet 14 on the split core 13A side. An induced voltage is generated in the U, V, or W phase coil 10 of the magnetic pole teeth 8 of the other divided core 9A by the permanent magnet 14 on the core 13B side. In this case, twelve U-phase stator coils 10 wound around the twelve magnetic pole teeth 8 of the rotor core 13 are connected in series, and twelve V-phase stators wound around the twelve magnetic pole teeth 8. Since the coils 10 are connected in series and the 12 W-phase stator coils 10 wound around the 12 magnetic pole teeth 8 are connected in series, the coils 10 of each phase are permanent on the divided core 13A side. This is the same as the case where an induced voltage is generated by the permanent magnet 14 on the divided core 13B side to generate an induced voltage by the magnet 14. From this point of view, as in the permanent magnet motor shown in FIG. 7, for example, if the amount of magnetic flux of the “small N” permanent magnet 114 is ½ of the amount of magnetic flux of the “large S” permanent magnet 15, Even in a configuration in which one pair of adjacent split cores 13A and 13B includes one permanent magnet 14 stone, a magnetic balance can be obtained.

  As described above, in one split core 13A, the low coercivity permanent magnet 14 is located first from the left side, and in the other split core 13B, the third low coercivity permanent magnet 14 is provided from the left side. Therefore, when one permanent magnet 14 corresponds to the U-phase magnetic pole tooth 8, for example, the other permanent magnet 14 does not correspond to the U-phase magnetic pole tooth 8, and is located at a position other than the U-phase magnetic pole tooth 8. Thus, the generation of torque ripple due to the two permanent magnets 14 corresponding to the magnetic pole teeth 8 having the same phase at the same time can be prevented.

As a result, according to the present embodiment, the adjustment of the amount of magnetic flux of the rotor 5 according to the load to be driven is selected from two types of permanent magnets having different coercive forces so that one type per one magnetic pole is selected. Even if the ratio of the permanent magnet having a small coercive force is reduced in the one realized by the simple configuration to be used, generation of torque ripple and cogging torque can be suppressed (second embodiment).
FIG. 5 shows a second embodiment of the present invention, in which the same parts as those in the first embodiment (FIG. 3) are denoted by the same reference numerals.

  As shown in FIG. 5, the rotor core 18 in place of the rotor core 13 is configured by combining three pairs of adjacent pairs of divided cores 18A and 18B. The divided cores 18A and 18B are configured by inserting and arranging eight permanent magnets 14 or 15 in eight magnet insertion holes 17 so that N and S poles are alternately formed. In one of the divided cores 18A, the permanent magnet 15 (with high coercive force) is arranged against the arrangement of the U, V, W, U, V, and W phase magnetic pole teeth 8 from one side (left side) of the divided core 9A. "Large N"), high coercivity permanent magnet 15 ("Large S"), low coercivity permanent magnet 14 ("Small N"), high coercivity permanent magnet 15 ("Large S"), high coercivity permanent magnet Magnet 15 (“large N”, high coercivity permanent magnet 15 (“large S”), high coercivity permanent magnet 15 (“large N”) and high coercivity permanent magnet 15 (“large S”) Has been placed.

  In the other split core 18B, the high coercive force permanent magnet 15 (“large N”, high coercive force) with respect to the arrangement of U, V, W, U, V, and W phases from one side (left side) of the split core 9A. Permanent magnet 15 ("large S"), high coercivity permanent magnet 15 ("large N", high coercivity permanent magnet 15 ("large S"), low coercivity permanent magnet 14 ("small N")) The high coercivity permanent magnet 15 (“Large S”), the high coercivity permanent magnet 15 (“Large N”), and the high coercivity permanent magnet 15 (“Large S”) are arranged to respond.

  As described above, the pair of split cores 18A and 18B includes one low-coercivity permanent magnet 14 and seven high-coercivity permanent magnets 15, and the total magnetic flux amount is substantially equal. However, in the pair of split cores 18A and 18B, in one split core 18A, the low coercive force permanent magnet 14 is positioned third from the left so as to be positioned on the center side, whereas the other core In the split core 18B, the arrangement order of the permanent magnets 14 and 15 is set so that the low coercive force permanent magnet 14 is located fifth from the left so as to be located on the center side.

  In the pair of split cores 18A and 18B, engagement convex portions 13a are formed at both ends of one split core 18A, and engagement recesses 13b are formed at both ends of the other split core 18B. ing. Similarly to the first embodiment, a pair of split cores 18A and 18B can be combined, but only the split cores 18A and 18A can be combined and the split cores 18B and 18B cannot be combined.

  According to the second embodiment, each pair of adjacent split cores 18A and 18B has one low-coercivity permanent magnet 14 and seven high-coercivity permanent magnets 15, so that the total magnetic flux amount Are substantially equal, and the magnetic balance of the adjacent divided cores 18A and 18B is good, and therefore the magnetic balance of the entire rotor 5 is good. In addition, in the pair of split cores 18A and 18B, the low coercivity permanent magnets 14 and 14 are located on the center side, so that the high coercivity permanent magnets are, for example, compared to the case where they are located on the end side. Thus, it is difficult to receive magnetic stress due to the difference in the amount of magnetic flux 15 and there is no possibility that the split cores 18A and 18B are deformed.

According to the second embodiment, the same operation and effect can be obtained by the same principle as that of the first embodiment.
(Third embodiment)
FIG. 6 shows a third embodiment of the present invention, in which the same parts as those in the first embodiment (FIG. 3) are denoted by the same reference numerals.

  A rotor core 19 in place of the rotor core 13 is configured by combining three pairs of a pair of split cores 19A and 19B as shown in FIG. The split cores 19A and 19B are configured by inserting and arranging eight permanent magnets 14 or 15 in the eight magnet insertion holes 17 so that N poles and S poles are alternately formed. In one of the split cores 19A, the permanent magnet 15 (with high coercive force) is arranged with respect to the arrangement of the U, V, W, U, V, and W phase magnetic pole teeth 8 from one side (left side) of the split core 9A. "Large N"), high coercivity permanent magnet 15 ("Large S"), high coercivity permanent magnet 15 ("Large N"), low coercivity permanent magnet 14 ("Small S"), high coercivity Permanent magnet 15 (“Large N”, high coercivity permanent magnet 15 (“Large S”), high coercivity permanent magnet 15 (“Large N”) and high coercivity permanent magnet 15 (“Large S”) Is arranged.

  In the other split core 19B, the high coercivity permanent magnet 15 (“large N”, high coercive force) with respect to the arrangement of U, V, W, U, V and W phases from one side (left side) of the split core 9A. Permanent magnet 15 ("large S"), high coercivity permanent magnet 15 ("large N", high coercivity permanent magnet 15 ("large S"), high coercivity permanent magnet 15 ("large N")), The low coercivity permanent magnet 14 (“small S”), the high coercivity permanent magnet 15 (“large N”), and the high coercivity permanent magnet 15 (“large S”) are arranged to respond.

  As described above, the pair of split cores 19A and 19B includes one low coercivity permanent magnet 14 and seven high coercivity permanent magnets 15, and the total amount of magnetic flux is substantially equal. However, in the pair of split cores 19A and 19B, in one split core 19A, the low coercive force permanent magnet 14 is positioned fourth from the left so as to be positioned on the center side, whereas the other core In the split core 19B, the arrangement order of the permanent magnets 14 and 15 is set so that the low coercive force permanent magnet 14 is located sixth from the left so as to be located on the center side.

  In the pair of split cores 19A and 19B, engagement convex portions 13a are formed at both ends of one split core 19A, and engagement recesses 13b are formed at both ends of the other split core 19B. ing. Similarly to the first embodiment, a pair of split cores 19A and 19B can be combined, but only the split cores 19A and 19A and the split cores 19B and 19B cannot be combined.

According to the third embodiment, the same effect can be obtained by the same principle as that of the first embodiment.
The present invention is not limited to the embodiments described above and shown in the drawings, but can be modified and expanded as follows.

  In the rotor cores 13, 18, and 19, a rectangular engaging convex portion 13 a is provided as an engaging portion in one divided core, and a rectangular engaging concave portion 13 b is provided as an engaged portion in the other divided core. Various shapes are conceivable. In short, two adjacent split cores are connected to each other by engagement between the engaging portion and the engaged portion, and the engaging portion of the split core that does not form a pair is engaged. The part should just be comprised so that engagement is impossible.

What is necessary is just to set the division | segmentation number of a rotor core suitably.
The arrangement order of the plurality of permanent magnets of the adjacent split cores may be the same.
The present invention can be applied not only to drum-type washing machines but also to washing machines in general.

  In the drawings, 1 is a drum type washing machine (washing machine), 3 is a drum (load, washing machine load), 4 is a permanent magnet motor, 5 is a rotor, 7 is a stator, 8 is a magnetic pole tooth, 9 is a stator core, 9A is Split core, 10 is a stator coil, 13 is a rotor core, 13A and 13B are split cores, 13a is an engaging projection (engaging portion) 13b is an engaging recess (engaged portion), and 14 is a low coercive force permanent magnet. , 15 is a permanent magnet with high coercive force, 17 is a magnet insertion hole, 18 is a rotor core, 18A and 18B are split cores, 19 is a rotor core, and 19A and 19B are split cores.

Claims (5)

In a permanent magnet motor comprising a permanent magnet that forms a large number of magnetic poles in the rotor core of the rotor, and a stator having magnetic pole teeth corresponding to the stator coil of each phase,
The rotor core is configured by combining a plurality of split cores having a plurality of magnet insertion holes in the circumferential direction,
A permanent magnet selected so as to be one type per pole from two types of permanent magnets having different coercive forces is inserted into the magnet insertion hole of the split core,
In the split core, the number of low coercivity permanent magnets is set to be smaller than the number of high coercivity permanent magnets,
A permanent magnet motor characterized in that a total magnetic flux amount of a plurality of permanent magnets is set to be substantially equal between adjacent divided cores.   When two adjacent cores have a low coercivity permanent magnet on one side corresponding to one phase magnetic pole teeth of the stator, the other low coercivity permanent magnet corresponds to a position other than the same phase magnetic pole teeth. The permanent magnet motor according to claim 1, wherein the permanent magnet motor is configured as described above.   The permanent magnet motor according to claim 1, wherein the two adjacent cores are configured such that the low coercive force permanent magnet is located at the center of each of the two divided cores.   Two adjacent split cores are connected to each other by engagement between the engaging portion and the engaged portion, and the engaging portion and the engaged portion of the split core that do not form a pair are configured to be non-engageable. The permanent magnet motor according to any one of claims 1 to 3.   A washing machine, wherein the washing machine load is rotationally driven by the permanent magnet motor according to any one of claims 1 to 4.

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