JP2010226915A - Permanent magnet motor, motor control system, and washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the adjustment ranges of the magnetic fluxes of permanent magnets by increasing the effective magnetic fluxes acting on the permanent magnets, while reducing the leakage of magnetic fluxes of the permanent magnets. <P>SOLUTION: The permanent magnet motor includes: a stator; a rotor having a rotor core 8 made of a soft magnetic material and rotatably provided on the stator; a plurality of kinds of permanent magnets which differ in coercive force; and a plurality of magnet holding portions 14, provided on a yoke portion 13 of the rotor core 8 and forming one magnetic pole for each, by arranging the permanent magnets one by one. The magnet-holding portions 14 each have a magnet insertion hole 15 formed in an axial direction, and an opening portion 16 formed on both ends in a circumferential direction, wherein the permanent magnets are put in a state such that both the end surfaces of the circumferential direction are exposed via the opening portion 16, while being inserted in the magnetic insertion holes 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a permanent magnet motor including a plurality of permanent magnets in a magnet holding portion of a rotor core, a motor control system including the permanent magnet motor, and a washing machine including the motor control system.

In this type of permanent magnet motor, the amount of magnetic flux (interlinkage magnetic flux) of the permanent magnet interlinked with the stator winding is changed according to the load (for example, the drum of the drum type washer / dryer) driven by the permanent magnet motor. Proper adjustment is desired.
However, the permanent magnet provided in the rotor core of the permanent magnet motor is generally composed of one type, and therefore the amount of magnetic flux of the permanent magnet is always constant. In this case, for example, if only a permanent magnet having a large coercive force is used, the induced voltage due to the permanent magnet at the time of high-speed rotation becomes extremely high, which may cause dielectric breakdown of electronic components. On the other hand, if it comprises only a permanent magnet with a small coercive force, the output at the time of low speed rotation will fall.

  Therefore, two types of permanent magnets having different coercive forces are arranged in the rotor core, and the magnetization state of the permanent magnets having a small coercive force is generated by an external magnetic field (current flowing in the stator winding) due to the armature reaction. The magnetic field is demagnetized or increased, and the amount of magnetic flux of the permanent magnet is thereby adjusted (for example, see Patent Document 1).

  Also, in this type of permanent magnet motor, both ends in the circumferential direction of the magnet holding portion of the rotor core interposed between the magnet insertion hole and the stator, that is, a magnetic path through which the magnetic flux of the permanent magnet easily passes. It is conceivable that the formed portion is provided with an opening communicating with the magnet insertion hole and opened on the stator side, thereby reducing magnetic flux leakage of the permanent magnet (for example, Patent Document 2). reference).

JP 2006-280195 A JP 2006-157996 A

  In the configuration as described in Patent Document 2, the permanent magnet inserted into the magnet insertion hole is in a state where both ends in the circumferential direction of the surface on the stator side are exposed to the stator side through the opening. . In such a configuration, when an external magnetic field caused by an armature reaction from the stator is applied to the permanent magnet, the external magnetic field is inserted into the magnet holding portion of the magnet holding portion at the central portion in the circumferential direction of the permanent magnet. It acts indirectly on the permanent magnet through a portion interposed between the hole and the stator. However, at both ends in the circumferential direction of the permanent magnet, the external magnetic field directly acts on the permanent magnet through the opening that opens to the stator side. Therefore, the external magnetic field due to the armature reaction from the stator acts on the permanent magnets unevenly, and the effective amount of magnetic flux acting on the permanent magnets is reduced. It gets smaller.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to adjust the amount of magnetic flux of a permanent magnet by an external magnetic field due to an armature reaction, and the permanent magnet while reducing magnetic flux leakage of the permanent magnet. The permanent magnet motor capable of increasing the effective magnetic flux amount acting on the magnetic field and increasing the adjustment range of the magnetic flux amount of the permanent magnet, the motor control system including the permanent magnet motor, and the motor control system It is in providing the washing machine provided with.

  The permanent magnet motor of the present invention includes a stator, a rotor core made of a soft magnetic material, a rotor provided rotatably with respect to the stator, and a plurality of types of permanent magnets having different coercive forces. A plurality of magnet holders which are provided in the yoke portion of the rotor core and form one magnetic pole per one by arranging the permanent magnets one by one, wherein the magnet holder is axially Magnet insertion holes and openings formed at both ends in the circumferential direction, and the permanent magnet is inserted into the magnet insertion holes and both end faces in the circumferential direction are the openings. It is characterized by being in an exposed state through the.

  A motor control system of the present invention includes the permanent magnet motor according to any one of claims 1 to 8 and a control unit that controls driving of the permanent magnet motor, and the coercive force is relatively controlled by the control unit. It is characterized in that it is configured to switch the magnetization state of the small permanent magnet.

  A washing machine of the present invention comprises the motor control system according to claim 9 and is configured to switch the magnetization state of the permanent magnet having a relatively small coercive force for each driving stroke by the control unit of the motor control system. It has the feature.

  According to the permanent magnet motor of the present invention, the effective magnetic flux acting on the permanent magnet can be increased while reducing the magnetic flux leakage of the permanent magnet, and the adjustment range of the magnetic flux of the permanent magnet can be increased. it can.

According to the motor control system of the present invention, the amount of magnetic flux of the permanent magnet can be adjusted efficiently.
According to the washing machine of the present invention, the amount of magnetic flux of the permanent magnet can be efficiently adjusted for each driving stroke.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of this invention is shown, The perspective view which shows schematically the whole structure of a permanent magnet motor The perspective view which shows the structure of a stator roughly The perspective view which shows the structure of a rotor roughly The perspective view which expands and shows a magnet holding | maintenance part and its periphery Sectional drawing which expands and shows a magnet holding part and its circumference Longitudinal side view schematically showing the internal structure of the drum type washing and drying machine Block diagram schematically showing the electrical configuration of the drum-type washing and drying machine FIG. 4 equivalent view according to the second embodiment of the present invention. Figure equivalent to FIG. FIG. 4 equivalent view according to the third embodiment of the present invention. Equivalent to FIG. FIG. 5 equivalent diagram showing the conventional configuration

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view schematically showing the overall configuration of a permanent magnet motor 1 (outer rotor type brushless motor). The permanent magnet motor 1 is composed of a stator 2 and a rotor 3 provided on the outer periphery of the stator 2 so as to be rotatable with respect to the stator 2.

  As shown in FIG. 2, the stator 2 includes a stator core 4 and a stator winding 5. The stator core 4 is formed by laminating and caulking a plurality of punched and formed soft magnetic bodies of silicon steel plates and projecting radially from an annular yoke portion 4a and an outer peripheral portion of the yoke portion 4a. And a large number of teeth 4b. The surface of the stator core 4 is covered with PET resin (mold resin) except for an outer peripheral surface 4c (a tip surface of each tooth portion 4b) that forms a gap with the inner peripheral surface of the rotor 3. A plurality of attachment portions 6 made of PET resin are integrally formed on the inner peripheral portion of the stator 2. These attachment portions 6 are provided with a plurality of screw holes 6a. By fixing these attachment portions 6 to each other, the stator 2 is in this case the water tank 25 of the drum type washing and drying machine 21 (see FIG. 6). It is supposed to be fixed to the back of the. In this case, the stator winding 5 is composed of three phases and is wound around each tooth portion 4b.

  As shown in FIG. 3, the rotor 3 has a configuration in which the frame 7, the rotor core 8, and the plurality of permanent magnets 9 are integrated with a mold resin (not shown). The frame 7 is formed into a flat bottomed cylindrical shape by pressing, for example, an iron plate, which is a magnetic body, and stands up from a circular main plate portion 7a and a stepped portion 7b from the outer peripheral portion of the main plate portion 7a. And an annular peripheral side wall 7c. A shaft mounting portion 10 for mounting a rotating shaft 26 (see FIG. 6) is provided at the center of the main plate portion 7a, and a plurality of ventilation holes are provided between the shaft mounting portion 10 and the step portion 7b. 11 and ribs 12 are formed radially about the shaft mounting portion 10.

  The rotor core 8 has a substantially annular shape as a whole, and is formed by laminating and caulking a number of silicon steel plates that are punched and formed of soft magnetic materials. The rotor core 8 is disposed on the inner peripheral portion of the peripheral side wall 7 c of the frame 7.

  The rotor core 8 includes a yoke portion 13 (see FIG. 4) constituting an annular portion of the rotor core 8 and a plurality of magnet holding portions 14 (see FIG. 4) protruding in an arc shape on the inner peripheral side of the yoke portion 13. 4). These magnet holding portions 14 are portions where magnetic poles are formed by the permanent magnets 9 arranged one by one in the magnet holding portion 14. That is, one magnetic pole is formed per one magnet holding portion 14. These magnet holding portions 14 include a rectangular magnet insertion hole 15 (see FIG. 4) that is long in the circumferential direction and a rectangular opening portion 16 that is long in the axial direction that opens at both circumferential sides of the magnet insertion hole 15 ( 4).

  The magnet insertion hole 15 is formed in the central portion of the magnet holding portion 14 so as to penetrate in the axial direction of the rotor core 8 (the lamination direction of the silicon steel plates). The magnet insertion holes 15 are arranged in the rotor core 8 so as to be arranged in a ring along the circumferential direction of the permanent magnet motor 1 (rotor core 8). The magnet insertion hole 15 has a short side direction (diameter direction of the permanent magnet motor 1) of 2.1 mm, a long side direction (circumferential direction of the permanent magnet motor 1) of 12.0 mm, and a depth direction. The dimension in the axial direction of the permanent magnet motor 1 is 19.0 mm. In addition, the dimension of each direction of the magnet insertion hole 15 can be changed and set suitably. The opening 16 is formed in communication with the magnet insertion hole 15 at both ends in the circumferential direction of the magnet holding portion 14.

  The permanent magnet 9 has a rectangular flat plate shape as a whole, and is inserted into the plurality of magnet insertion holes 15 described above. The permanent magnet 9 inserted into the magnet insertion hole 15 has a substantially entire surface on the stator 2 side and a substantially entire surface on the yoke portion 13 side of the surface thereof, and a substantially entire area on the stator 2 side of the inner surface of the magnet insertion hole 15. And it will be in the state which contacted and hold | maintained the substantially whole area on the yoke part 13 side. In this case, these permanent magnets 9 are composed of a neodymium magnet 9a which is a high coercive force permanent magnet having a large coercive force, and a samakoba magnet 9b (samarium / cobalt magnet) which is a low coercive force permanent magnet having a small coercive force. . That is, each of the permanent magnets 9a and 9b is composed of a neodymium magnet and a sumaboba magnet which are rare earth magnets. In FIG. 1 and FIG. 3, the permanent magnets shown in white are neodymium magnets 9a, and the permanent magnets shown in black are sumakoba magnets 9b.

  In this case, the coercive force of the neodymium magnet 9a is about 900 kA / m, the coercive force of the sumakoba magnet 9b is about 200 to 500 kA / m, and the coercive force differs by about 1.8 to 4.5 times. That is, the permanent magnet 9 is composed of two types of permanent magnets 9a and 9b having different coercive forces. The permanent magnets 9a and 9b are substantially annular in the rotor core 8 and have one magnet holding portion 14 (magnet). The insertion holes 15) are alternately arranged one by one.

  Note that the neodymium magnet 9a has a high coercive force and the Samakova magnet 9b has a low coercive force because the external magnetic field (current flowing through the stator winding 5) from the stator 2 (stator winding 5) due to the armature reaction. In the standard that the magnetization amount of the neodymium magnet 9a does not change at a current that can change the magnetization amount of the Samacoba magnet 9b when the magnetic field generated by This is called low coercivity.

  Further, each of these two types of permanent magnets 9a and 9b is formed of one type of permanent magnet to form one magnetic pole, and its magnetization direction is the radial direction of the permanent magnet motor 1 (from the outer periphery of the permanent magnet motor 1 to the stator). 2 in the direction toward the gap between the rotor 3 and the rotor 3). In this way, by arranging the two types of permanent magnets 9a and 9b alternately and so that the magnetization direction is along the radial direction, the permanent magnets 9a and 9b arranged next to each other have magnetic poles in opposite directions. A magnetic path (for example, in the direction indicated by an arrow B (see FIG. 3) between the neodymium magnet 9a and the Samacoba magnet 9b. Magnetic flux). 3 indicates a magnetic flux that passes through the yoke portion 13 of the rotor core 8.

  With such a configuration, a magnetic path is formed that passes through both the neodymium magnet 9a having a large coercive force and the sumakoba magnet 9b having a small coercive force. In this case, the permanent magnet motor 1 has a 48-pole / 36-slot configuration (a configuration in which 36 teeth 4b are provided for 48 permanent magnets 9), and 4 poles per 3 slots. Corresponds to (4-pole / 3-slot configuration).

  Next, the configuration of the rotor core 8 described above will be described in detail with reference to FIGS. 4 is an enlarged perspective view showing the magnet holding portion 14 of the rotor core 8 and the periphery thereof, and FIG. 5 is a cross-sectional view showing the magnet holding portion 14 of the rotor core 8 and the periphery thereof enlarged (FIG. 4). FIG. 4 is a view showing a state in which the second steel plate 8b at the front side of the middle is removed.

  The rotor core 8 is configured by laminating and caulking a first steel plate 8a and a second steel plate 8b having different shapes. The first steel plate 8a includes a steel plate piece 13a forming the yoke portion 13 and a tip portion 17 of the magnet holding portion 14 (a portion interposed between the magnet insertion hole 15 and the stator 2 in the magnet holding portion 14). It consists of the steel plate piece 17a to form. As shown also in FIG. 5, this steel plate piece 17a has a portion on the stator 2 side (a portion constituting the inner peripheral portion of the rotor core 8) formed in an arc shape, and a portion on the yoke portion 13 side (magnet insertion). The portion of the hole 15 constituting the inner surface on the stator 2 side) is formed in a straight line. In this case, the steel plate piece 17a is an independent steel plate piece completely separated from the steel plate piece 13a.

  On the other hand, the second steel plate 8 b includes a steel plate piece 13 b that forms the yoke portion 13 and a steel plate piece 17 b that forms the tip portion 17 of the magnet holding portion 14. In this case, the steel plate piece portion 13b and the steel plate piece portion 17b are integrally formed via a bridge portion 18 that connects the steel plate piece portion 13b and both end portions in the circumferential direction of the steel plate piece portion 17b.

  The rotor core 8 forms a laminated body 8d (see FIG. 4) by laminating a plurality of first steel plates 8a, and both ends of the laminated body 8d in the lamination direction (axial direction of the rotor core 8). Each part is formed by laminating a second steel plate 8b. That is, the yoke portion 13 is composed of a plurality of stacked steel plate pieces 13a and two steel plate pieces 13b stacked on both ends in the stacking direction. Moreover, the front-end | tip part 17 of the magnet holding | maintenance part 14 is comprised from the laminated | stacked several steel plate piece 17a, and the two steel plate piece parts 17b each laminated | stacked at the both ends of the lamination direction.

  The yoke portion 13 and the tip portion 17 of the magnet holding portion 14 are connected to each other at both ends in the axial direction via only the bridge portion 18, and the yoke portion 13 and the tip portion 17 are left with the both ends in the axial direction being left. Are separated. The bridge portion 18 of the second steel plate 8b constitutes both end portions in the circumferential direction of the magnet insertion hole 15 in the circumferential direction of the rotor core 8, and the opening portion 16 in the axial direction of the rotor core 8. The both ends of the axial direction of are comprised.

In the magnet holding part 14 of the rotor core 8 configured in this way, the permanent magnets 9 (neodymium magnets 9a and samacoba magnets 9b) are inserted in the magnet insertion holes 15 and both end surfaces in the circumferential direction are open. It will be in the state exposed to the space | gap between the stator 2 and the rotor 3 via the part 16. FIG. In addition, the part where the permanent magnet 9 inserted into the magnet insertion hole 15 faces the stator 2 side (in this case, the surface of the permanent magnet 9 on the stator 2 side), and the part where the magnet insertion hole 15 is in contact with this part ( In this case, a surface formed by a portion on the yoke portion 13 side of the plurality of stacked steel plate pieces 17a and an inner surface on the stator 2 side of the magnet insertion hole 15) is formed in a planar shape. ing.
According to such a configuration, the permanent magnet 9 inserted into the magnet insertion hole 15 is in a state where almost the entire surface on the stator 2 side is covered with the tip portion 17 of the magnet holding portion 14.

  As shown in FIG. 12, in the conventional magnet insertion hole of the general rotor 101, protrusions 102 projecting toward the yoke part are formed at both circumferential ends of the magnet insertion hole. In such a configuration, a magnetic path through which the magnetic flux of the permanent magnet 9 easily passes is formed in the protruding portion 102, and magnetic flux leakage of the permanent magnet 9 occurs, and an external magnetic field is easily concentrated on the protruding portion 102. End up. For this reason, in the present embodiment, such protrusions are removed from both circumferential ends of the magnet insertion hole 15.

  Further, the protrusion 19 (see FIG. 5) protruding between the magnet holding portions 14 toward the inner peripheral side of the yoke portion 13 is formed with less protrusion than the protrusion 103 (see FIG. 12) in the conventional configuration. ing. Thereby, both end surfaces in the circumferential direction of the permanent magnet 9 inserted into the magnet insertion hole 15 are widely opened to the gap between the stator 2 and the rotor 3 through almost the entire area of the opening 16. It has become.

Next, the structure of the drum type washing / drying machine 21 provided with the permanent magnet motor 1 configured as described above will be described. FIG. 6 is a longitudinal sectional side view schematically showing the internal configuration of the drum type washing and drying machine 21.
The outer box 22 forming the outer shell of the drum-type washing / drying machine 21 has a laundry entrance / exit 23 opened in a circular shape on the front surface. The laundry entrance / exit 23 is opened and closed by a door 24. ing. Inside the outer box 22, a bottomed cylindrical water tank 25 with a closed back surface is disposed, and the permanent magnet motor 1 (stator 2) is screwed to the center of the back surface of the water tank 25. It is fixed. The rotating shaft 26 of the permanent magnet motor 1 has a rear end portion (right end portion in FIG. 6) fixed to the shaft mounting portion 10 of the permanent magnet motor 1 (rotor 3), and a front end portion (in FIG. 6). The left end) protrudes into the water tank 25. A bottomed cylindrical drum 27 whose back is closed is fixed to the front end of the rotating shaft 26 so as to be coaxial with the water tank 25, and this drum 27 is driven by the permanent magnet motor 1. It rotates integrally with the rotor 3 and the rotating shaft 26. The drum 27 is provided with a plurality of flow holes 28 through which air and water can flow, and a plurality of baffles 29 for scraping and unraveling the laundry in the drum 27.

  A water supply valve 30 is connected to the water tank 25, and water is supplied into the water tank 25 when the water supply valve 30 is opened. Further, a drain hose 32 having a drain valve 31 is connected to the water tank 25, and when the drain valve 31 is opened, water in the water tank 25 is discharged.

  A ventilation duct 33 extending in the front-rear direction is provided below the water tank 25. A front end portion of the ventilation duct 33 is connected to the water tank 25 via the front duct 34, and a rear end portion is connected to the water tank 25 via the rear duct 35. A blower fan 36 is provided at the rear end portion of the ventilation duct 33, and the air in the water tank 25 is moved from the front duct 34 into the ventilation duct 33 by the blowing action of the blower fan 36 as indicated by an arrow. And is returned to the water tank 25 through the rear duct 35.

  An evaporator 37 is disposed on the front side inside the ventilation duct 33, and a condenser 38 is disposed on the rear side. The evaporator 37 and the condenser 38 constitute a heat pump 40 together with the compressor 39 and a throttle valve (not shown), and the air flowing in the ventilation duct 33 is dehumidified by the evaporator 37 and heated by the condenser 38. And is circulated in the water tank 25.

  An operation panel 41 is provided on the front surface of the outer box 22 above the door 24. The operation panel 41 is provided with a plurality of operation switches (not shown) for setting a driving course and the like. ing. The operation panel 41 is composed mainly of a microcomputer and is connected to a control circuit unit 42 (corresponding to a control unit) that controls the overall operation of the drum-type washing and drying machine 21, and the control circuit unit 42 is connected to the operation panel 41. Various operation courses are executed while controlling the drive of the permanent magnet motor 1, the water supply valve 30, the drain valve 31, the compressor 39, the throttle valve, and the like according to the contents and control programs set via the control.

  Further, a magnetic sensor 43 (see FIG. 7) that detects the magnetism of the permanent magnet 9 is disposed at a portion facing the permanent magnet 9 in the permanent magnet motor 1. The magnetic sensor 43 is mounted on a circuit board (not shown) attached to the stator 2 side. As shown in FIG. 7, the control circuit unit 42 calculates the rotational position of the rotor 3 based on the detection signal from the magnetic sensor 43. Then, an inverter circuit 44 in which six IGBTs 44a (only two are shown in FIG. 7) are connected in a three-phase bridge is driven by the gate drive signal G corresponding to the calculation result, thereby the stator winding 5 The rotor 3 is rotated while controlling the energization. The control circuit unit 42 constitutes the motor control system 45 of the present invention together with the permanent magnet motor 1.

Next, the operation of the drum type washer / dryer 21 provided with the permanent magnet motor 1 as described above will be described.
When the control circuit unit 42 of the motor control system 45 energizes the stator winding 5 via the inverter circuit 44, an external magnetic field (magnetic field generated by the current flowing through the stator winding 5) due to the armature reaction is generated in the rotor 3. The permanent magnets 9a and 9b are acted on. Of these permanent magnets 9 a and 9 b, the magnetization state of the small coke magnet 9 b having a small coercive force is demagnetized or increased by an external magnetic field due to this armature reaction, and thereby interlinks with the stator winding 5. The amount of magnetic flux (interlinkage magnetic flux amount) can be increased or decreased. Therefore, in the present embodiment, the motor control system 45 controls the energization of the stator winding 5 by the control circuit unit 42, thereby changing the magnetization state of the Samakoba magnet 9b in the operation process (for example, washing process, dehydration process, drying process). The process is switched and executed every time. Here, the operation content in each driving process will be described in order.

  First, in the washing process, the control circuit unit 42 opens the water supply valve 30 to supply water into the water tank 25, and then rotates the drum 27 to perform washing. In this washing process, it is necessary to rotate the drum 27 with high torque in order to scoop up the laundry containing water, but the rotation speed may be low. Therefore, the motor control system 45 controls the energization of the stator winding 5 by the inverter circuit 44 via the control circuit unit 42 so that the magnetization state of the Samakoba magnet 9b is increased. As a result, the amount of magnetic flux acting on the stator winding 5 is large (the magnetic force is strong), so that the drum 27 can be rotated at high torque and low speed.

  Next, in the dehydration process, the control circuit unit 42 opens the drain valve 31 to discharge the water in the water tank 25, and then dehydrates the moisture contained in the laundry by rotating the drum 27 at a high speed. In this dewatering process, it is necessary to rotate the drum 27 at a high speed in order to improve the dewatering efficiency, but the torque may be small. Therefore, the motor control system 45 controls the energization of the stator winding 5 by the inverter circuit 44 via the control circuit unit 42 so that the magnetization state of the Samakoba magnet 9b is demagnetized. As a result, the amount of magnetic flux acting on the stator winding 5 is reduced (the magnetic force is weak), so that the drum 27 can be rotated at a low torque and a high speed.

  Finally, in the drying process, the control circuit unit 42 dries the laundry by driving the blower fan 36 and the heat pump 40 and rotating the drum 27. In this drying process, the motor control system 45 prepares the stator winding 5 by the inverter circuit 44 via the control circuit unit 42 so that the magnetization state of the Samacoba magnet 9b is increased in preparation for the next washing process. Control energization. Thereby, it can be set as the state which increased the magnetic flux amount which acts on the stator coil | winding 5, and can make it easy to rotate the drum 27 at high torque low speed in the next washing process.

  As described above, according to the present embodiment, the rotor 3 has both the stator 2 and the rotor 3 that have both end faces in the circumferential direction of the permanent magnet 9 inserted into the magnet insertion hole 15 through the opening 16. It is in the state exposed in the space | gap between. Therefore, in the permanent magnet motor 1 including the rotor 3 having such a configuration, an external magnetic field due to the armature reaction from the stator 2 is fixed to the permanent magnet 9 via the tip 17 of the magnet holding portion 14. It acts evenly from the entire surface on the child 2 side and with little leakage to both end surfaces in the circumferential direction of the permanent magnet 9. As a result, the effective magnetic flux acting on the permanent magnet 9 can be increased while reducing the magnetic flux leakage of the permanent magnet 9, and the adjustment range of the magnetic flux of the permanent magnet 9 can be increased.

  Further, in the permanent magnet motor 1, in the magnet holding portion 14, a portion where the permanent magnet 9 faces the stator 2 side (a surface on the stator 2 side of the permanent magnet 9), and a portion where the magnet insertion hole 15 contacts the portion. (The inner surface of the magnet insertion hole 15 on the stator 2 side) is formed in a planar shape. Here, when the inner surface of the magnet insertion hole 15 is stepped or a protrusion is formed, the interval between the magnet insertion holes 15 at that portion (the distance between the yoke portion 13 and the tip portion 17) is shortened. , The magnetic resistance of the portion is reduced. Therefore, the external magnetic field due to the armature reaction from the stator 2 (stator winding 5) is concentrated on such a portion having a small magnetic resistance. Therefore, the external magnetic field cannot be applied to the permanent magnet 9 uniformly and efficiently, and it becomes difficult to adjust the magnetization state. According to the present embodiment, since the inner surface of the magnet insertion hole 15 is flat and comes into contact with the permanent magnet 9 uniformly, the external magnetic field is uniformly concentrated without being concentrated on a part of the permanent magnet 9. It can be made to work well, and the magnetization state can be easily adjusted.

  In addition, the load that is driven by demagnetizing or increasing the magnetization state of the small coercive magnet 9b of the two types of permanent magnets 9a and 9b having different coercivity by an external magnetic field due to the armature reaction (this embodiment) In the embodiment, the amount of magnetic flux of the permanent magnet 9 can be adjusted according to the drum 27) of the drum type washer / dryer 21. As a result, the amount of magnetic flux of the permanent magnet 9 is not always constant, and it is possible to prevent dielectric breakdown during high-speed rotation and output reduction during low-speed rotation.

  In addition, the configuration in which two types of permanent magnets 9a and 9b having different coercive forces are arranged alternately and substantially circularly with one type per magnetic pole is simple, and the load to be driven with such a simple configuration Adjustment of the magnetic flux amount of the permanent magnet 9 according to (drum 27) can be realized.

  In addition, the magnetic path formed by the two types of permanent magnets 9a and 9b passes through both the neodymium magnet 9a having a large coercive force and the sumakoba magnet 9b having a small coercive force. Thereby, the magnetic flux amount of all the magnetic paths can be made substantially the same, and the drum 27 can be driven with a stable magnetic flux amount.

Further, according to the motor control system 45 of the present embodiment, the amount of magnetic flux of the permanent magnet 9 can be adjusted efficiently.
Moreover, according to the drum type washing / drying machine 21 of this embodiment, the magnetic flux amount of the permanent magnet 9 can be adjusted efficiently according to the driving process.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, description is abbreviate | omitted about the same part as 1st Embodiment mentioned above, and only a different part is demonstrated. In the present embodiment, in the magnet holding portion 51, the circumferential width of the portion where the permanent magnet 9 faces the stator 2 side and the circumferential width of the portion where the magnet insertion hole 52 is in contact with that portion are the same. It is different from the first embodiment described above in that it is formed.

  That is, the 1st steel plate 8a which comprises the rotor core 8 consists of the steel plate piece 13a and the steel plate piece 53a replaced with the above-mentioned steel plate piece 17a. As shown also in FIG. 9, this steel plate piece 53a has a portion on the stator 2 side (a portion constituting the inner peripheral portion of the rotor core 8) formed in an arc shape, and a portion on the yoke portion 13 side (magnet insertion). The portion of the hole 52 constituting the inner surface of the stator 2 side) is formed in a straight line. Further, the steel plate pieces 53 a are formed such that both circumferential ends thereof are cut off and the circumferential width thereof is substantially the same as the circumferential width of the magnet insertion hole 52. And the front-end | tip part 53 (The part interposed between the magnet insertion hole 52 and the stator 2 among the magnet holding | maintenance parts 51) of the magnet holding | maintenance part 51 of this embodiment is the laminated | stacked several steel plate piece 53a, It is comprised from the two steel plate piece parts 17b each laminated | stacked at the both ends of the lamination direction.

  In the magnet holding portion 51 of the rotor core 8 configured as described above, the permanent magnet 9 is inserted into the magnet insertion hole 52, and both end surfaces in the circumferential direction are connected to the stator 2 via the opening 54. It will be in the state exposed to the space | gap between the rotors 3. In addition, the circumferential width of the portion where the permanent magnet 9 inserted into the magnet insertion hole 52 faces the stator 2 side (in this case, the surface of the permanent magnet 9 on the stator 2 side), and the magnet insertion hole 52 in that portion. The width in the circumferential direction of the portion in contact with (in this case, the surface formed by the portion on the yoke portion 13 side of the plurality of laminated steel plate pieces 53a and the inner surface on the stator 2 side of the magnet insertion hole 52) Are formed to be substantially the same.

  According to the present embodiment, the permanent magnet 9 inserted into the magnet insertion hole 52 is in a state where almost the entire surface on the side of the stator 2 is covered with the tip portion 53 of the magnet holding portion 51. Further, at both ends in the circumferential direction of the permanent magnet 9, the protruding portion protruding toward the yoke portion 13 side is removed, and the protruding amount of the protruding portion 55 between the magnet holding portions 51 is formed low. It has a configuration. Moreover, the circumferential width of the portion (the portion formed by the plurality of steel plate pieces 53 a) that leaves both end portions in the axial direction in the tip portion 53 of the magnet holding portion 51 is substantially the same as the circumferential width of the permanent magnet 9. Therefore, the magnetic flux leakage is further prevented as compared with the configuration in which the circumferential width of the tip portion of the magnet holding portion is larger than the circumferential width of the permanent magnet 9.

  Therefore, the external magnetic field due to the armature reaction from the stator 2 is uniformly distributed from the entire surface of the permanent magnet 9 on the stator 2 side via the tip 53 of the magnet holding portion 51, and in the circumferential direction of the permanent magnet 9. It comes to operate with almost no leakage to both end surfaces. As a result, the effective magnetic flux acting on the permanent magnet 9 can be increased while reducing the magnetic flux leakage of the permanent magnet 9, and the adjustment range of the magnetic flux of the permanent magnet 9 can be increased.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. In each of the above-described embodiments, the configuration in which the openings 16 and 54 are formed at both end portions of the magnet holding portions 14 and 51 in the circumferential direction is shown. In the present embodiment, the magnet holding portions 61 and 71 are configured not to have openings at both ends in the circumferential direction.

  That is, the magnet holding part 61 shown in FIG. 10 has a configuration in which the bridge part 18 is removed from the magnet holding part 14 shown in the first embodiment. Accordingly, at both ends in the circumferential direction of the magnet holding portion 61, open portions 62 opened in a slit shape are formed over the entire length in the axial direction of the rotor core 8 instead of the above-described opening portion 16 (see FIG. 4). .

  Moreover, the magnet holding | maintenance part 71 shown in FIG. 11 becomes a structure which removed the bridge | bridging part 18 in the magnet holding | maintenance part 51 shown in the above-mentioned 2nd Embodiment. Therefore, at both ends in the circumferential direction of the magnet holding portion 71, an opening portion 72 that is opened in a slit shape is formed over the entire length in the axial direction of the rotor core 8 instead of the above-described opening portion 54 (see FIG. 8). .

  The configuration shown in FIGS. 10 and 11 is, for example, a magnet insertion hole of the magnet holding portions 61 and 71 (not shown, but the magnet insertion hole 15 shown in the first embodiment and the second embodiment described above). , 52), the permanent magnet 9 is inserted, the rotor core 8 and the permanent magnet 9 are fixed with a mold resin, and then the bridge portion 18 is cut with a laser or the like.

  In the magnet holding portions 61 and 71 configured as described above, both end surfaces of the permanent magnet 9 in the circumferential direction are exposed to the gap between the stator 2 and the rotor 3 through the open portions 62 and 72. It becomes a state. In addition, the permanent magnet 9 is fixedly arranged on the yoke portion 13 of the rotor core 8 so that there is one type per magnetic pole. Further, the tip portions 63 and 73 (corresponding to the separation core portion) of the magnet holding portions 61 and 71 are completely separated from the yoke portion 13 of the rotor core 8, and the permanent magnet 9 faces the stator 2 side. It will be in the state fixedly arranged on the surface.

  According to the present embodiment, the permanent magnet 9 is in a state where almost the entire surface on the stator 2 side is covered by the tip portions 63 and 73 of the magnet holding portions 61 and 71. Accordingly, the external magnetic field due to the armature reaction from the stator 2 is uniformly distributed from the entire surface of the permanent magnet 9 on the stator 2 side through the tip portions 63 and 73 of the magnet holding portions 61 and 71, and the permanent magnet 9. It acts without almost leaking to both end faces in the circumferential direction. As a result, the effective magnetic flux acting on the permanent magnet 9 can be increased while reducing the magnetic flux leakage of the permanent magnet 9, and the adjustment range of the magnetic flux of the permanent magnet 9 can be increased.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
The openings 16 and 54 shown in the first embodiment and the second embodiment are formed at least in the magnet holding portions 14 and 51 in which permanent magnets having a relatively small coercive force are arranged, and the coercive force is relatively It is good also as a structure which is not formed in the magnet holding | maintenance part by which a large permanent magnet is arrange | positioned. In addition, the open portions 62 and 72 shown in the third embodiment are formed at least in the magnet holding portions 61 and 71 in which permanent magnets having a relatively small coercive force are arranged, so that the permanent coercive force is relatively large. It is good also as a structure which does not form in the magnet holding | maintenance part by which a magnet is arrange | positioned.

  A magnet that can be used as a low-coercivity permanent magnet with a small coercive force is not limited to the above-described sumakoba magnet 9b, and a permanent magnet with a low coercivity that can change the amount of magnetization by an external magnetic field due to an armature reaction Any material can be used. Examples of such a permanent magnet having a small coercive force include an alnico magnet (aluminum / nickel / cobalt magnet), a ferrite magnet, or a neodymium magnet having a relatively small coercive force. Further, the high coercive force permanent magnet having a large coercive force is not limited to the neodymium magnet 9a.

  Therefore, the combination of the two types of permanent magnets 9 having different coercive forces is not limited to the combination of the neodymium magnet 9a and the Samakova magnet 9b. A combination of magnets can be used. In addition, it is preferable that these two types of permanent magnets 9 differ in coercive force approximately twice or more.

  The permanent magnet 9 is not limited to two types, and may be composed of three types of permanent magnets having large, medium, and small coercive forces, or composed of a plurality of types of permanent magnets such as four types and five types. May be. In this case, the motor control system 45 may switch the magnetization state of the permanent magnet having a relatively small coercive force among these permanent magnets for each operation stroke by the control circuit unit 42.

  The means for adjusting the amount of magnetic flux of the permanent magnet 9 is not limited to the configuration in which the energization of the stator winding 5 is controlled by the inverter circuit 44. For example, a winding different from the stator winding 5 is provided. A configuration may be adopted in which energization of the winding is controlled.

The present invention is not limited to a 48-pole / 36-slot motor, but can be applied to a motor having a 4-pole / 3-slot structure as a basic unit, or a motor having another structure as a basic unit.
The permanent magnet motor 1 of the present invention is applicable not only to the above-described drum type washing and drying machine 21, but also to a washing machine having no drying function and a vertical washing machine in which the axial direction of the rotating tub is vertical. can do. Further, the present invention can be applied not only to the outer rotor type permanent magnet motor 1 as described above but also to an inner rotor type motor in which a rotor is rotatably provided on the inner periphery of the stator. Furthermore, the present invention can be applied to various motors such as a compressor driving motor mounted on an air conditioner or the like.

  In the drawings, 1 is a permanent magnet motor, 2 is a stator, 3 is a rotor, 8 is a rotor core, 9 is a permanent magnet, 9a is a neodymium magnet, 9b is a summer coba magnet, 13 is a yoke portion, 14, 51, 61 , 71 is a magnet holding part, 15, 52 are magnet insertion holes, 16, 54 are openings, 21 is a drum type washing and drying machine (washing machine), 42 is a control circuit part (control part), 45 is a motor control system, 63 and 73 show the front-end | tip part (separation core part) of a magnet holding | maintenance part.

Claims (11)

A stator,
A rotor core made of a soft magnetic material, and a rotor provided rotatably with respect to the stator;
Multiple types of permanent magnets with different coercivity,
A plurality of magnet holding portions that are provided in the yoke portion of the rotor core and that form one magnetic pole per one by arranging the permanent magnets one by one;
The magnet holding portion has a magnet insertion hole formed in the axial direction and openings formed at both ends in the circumferential direction,
The permanent magnet motor, wherein the permanent magnet is inserted into the magnet insertion hole and both end faces in the circumferential direction are exposed through the opening.   2. The permanent magnet according to claim 1, wherein in the magnet holding portion, a portion where the permanent magnet faces the stator side and a portion where the magnet insertion hole is in contact with the portion are formed in a planar shape. Magnet motor.   In the magnet holding part, the circumferential width of the portion where the permanent magnet faces the stator side and the circumferential width of the portion where the magnet insertion hole is in contact with the portion are the same. The permanent magnet motor according to claim 1.   The permanent magnet motor according to any one of claims 1 to 3, wherein the opening is formed at least in the magnet holding portion in which the permanent magnet having a relatively small coercive force is disposed.   The permanent magnet motor according to any one of claims 1 to 4, wherein the permanent magnets are arranged in a substantially annular shape.   The permanent magnet motor according to any one of claims 1 to 5, wherein the permanent magnet is composed of two types of permanent magnets having different coercive forces.   The permanent magnet motor according to claim 6, wherein the two types of permanent magnets have different coercive forces by a factor of two or more. A rotor core made of a soft magnetic material and having a yoke portion;
A plurality of types of permanent magnets having different coercive forces, which are fixedly disposed on the yoke portion so as to have one type per magnetic pole;
A separation core portion made of a soft magnetic material, the permanent magnet being fixedly disposed on a surface facing the stator side, and
The permanent magnet motor is characterized in that both end faces in the circumferential direction are exposed. A permanent magnet motor according to any one of claims 1 to 8,
A control unit for controlling the driving of the permanent magnet motor,
A motor control system configured to switch the magnetization state of the permanent magnet having a relatively small coercive force by the control unit. A motor control system according to claim 9,
The washing machine, wherein the controller of the motor control system is configured to switch the magnetization state of the permanent magnet having a relatively small coercive force for each driving stroke.   The washing machine according to claim 10, wherein the operation process is any one of washing, dehydration, and drying.

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