JP6353764B2 - Permanent magnet type rotating electric machine and vertical washing machine - Google Patents

Description

  The present invention relates to a permanent magnet type rotating electric machine employing a concentrated winding stator and a washing machine using the same.

  An inverter-driven permanent magnet type rotating electrical machine is adopted as the rotating electrical machine that drives the rotating blades of the washing machine. In particular, in a vertical washing machine, a direct drive type rotating electric machine has a problem that the motor size is large and the washing machine becomes heavy. Further, the belt-driven rotating electrical machine has an advantage that the physique becomes smaller as the speed is increased. However, the strength of the rotor core of the magnet rotor becomes a problem, and there is a limit to speeding up. On the other hand, the belt + reduction gear drive system does not need to increase the speed as much, but there is a problem that the influence of the armature reaction is large and the noise becomes large because the body cannot be multipolarized. As a countermeasure against this, as a countermeasure for suppressing the armature reaction, a method of forming a slit in the magnetic pole core of the rotor core has been proposed (see Patent Document 1). Further, it has been proposed to reduce the armature reaction by making the induced voltage waveform close to a sine wave by providing a leakage flux suppression hole in the stator magnetic pole iron core of the teeth to reduce the leakage flux (see Patent Document 2). ).

Japanese Patent Laid-Open No. 7-336917 JP-A-8-275415

  In the prior art described in Patent Document 1, in a rotating electrical machine employing a distributed winding stator, a slit is formed in the magnetic core of the rotor core, and the inductance of the stator winding is reduced to improve the output. . On the other hand, since the mechanical strength of the rotor core decreases due to the formation of slits, the output may decrease if it is necessary to increase the width of the outer peripheral core of both side ends of the permanent magnet. It was.

  In the prior art described in Patent Document 2, a method is proposed in which a hole for suppressing the flow of magnetic flux is formed in the pole shoe portion of the tooth so that the induced voltage is made closer to a sine wave. However, since the rotating electrical machines used in washing machines have a large capacity and are always operated in a load state, the voltage waveform supplied from the inverter and the rotation speed must be changed to the sine wave instead of the induced voltage. Deviations occur between the voltage waveforms generated by the electric machine, and harmonic current flows from the inverter to the rotating electric machine, which may generate pulsating torque and cause problems such as noise.

  An object of the present invention is to provide a permanent magnet type rotating electrical machine that has improved output while maintaining the mechanical strength of a rotor core, and a washing machine using the same.

  In order to solve the above-described object, the present invention has a stator in which concentrated armature windings are provided so as to surround teeth in a plurality of slots formed in the stator core, and the rotor core In the permanent magnet type rotating electrical machine, in which a rotor in which permanent magnets are housed in a plurality of permanent magnet insertion holes formed in the rotor is rotatably supported through a predetermined gap on the inner periphery of the stator, the rotor When the central axis in the radial direction of the arc-shaped permanent magnet embedded in the iron core is the d axis and the axis that is 90 degrees apart from the electrical angle is the q axis, the rotor magnet core on the rotor outer circumference side of the permanent magnet A d-axis slit that is long in the radial direction is provided, and a magnetic bridge formed by denting a part of the outer peripheral side of the q-axis side rotor core to the inner diameter side is provided between the permanent magnets or on the q-axis. On the inner diameter side of the permanent magnet, a circular or elliptical q-axis The outer peripheral side of the magnetic bridge, the d-axis slit, and the q-axis slit are molded by injection molding, and both axial ends of the rotor, the d-axis slit, and the q-axis slit are molded. The mold was connected.

  According to the aspect of the present invention, since the centrifugal force strength of the magnetic bridge is increased, it is possible to form irregularities on the outer peripheral surface of the magnetic bridge so that the magnetic bridge width is thin, and as a result, the leakage flux of the permanent magnet is reduced. It is possible to provide a permanent magnet type rotating electric machine with reduced output and an improved vertical washing machine using the same.

It is an Example which shows radial sectional drawing of the rotor by embodiment of this invention. It is the elements on larger scale of the rotor of the permanent magnet type rotary electric machine of FIG. It is an external view of the rotor of the permanent magnet type rotary electric machine of FIG. FIG. 4 is a perspective view of a rotor of the permanent magnet type rotating electric machine of FIG. 3. It is RR sectional drawing of the rotor of the permanent magnet type rotary electric machine of FIG. It is QQ sectional drawing of the rotor of the permanent magnet type rotary electric machine of FIG. It is sectional drawing of the stator combined with the rotor of a permanent magnet type rotary electric machine. It is an example of a drum type washing machine. It is an intensity | strength calculation result explaining the effect by embodiment of this invention. It is a figure which shows the rotor by other embodiment of this invention. It is a figure which shows the rotor by another embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

FIG. 8 shows an example of the vertical washing machine 50. The outer frame 51, the outer frame base 52 that supports the outer frame 51 from below, the top cover 53 provided on the outer frame 51, and the top cover 53 can be freely opened and closed. The lid body 54 is provided. The outer tub 55 is supported by a suspension rod 57 suspended from a corner support 58 provided inside the upper side of the outer frame 51 via a vibration isolation spring 28.
The washing tub 59 is rotatably placed in the outer tub 55. The electric motor for washing and dehydrating is the permanent magnet type rotating electrical machine 1 and is securely fixed to the bottom side lower surface of the outer tub 55. A drive pulley 67 is fastened to the shaft end of the permanent magnet type rotating electrical machine 1.

  The stirring blade 61 is rotatably installed in the washing tub 59, and the gear case 64 is fixed directly below the stirring blade 61 on the outer lower surface of the outer tub 55. The clutch 63 provided at the lower part of the gear case 64 has a driven pulley 65. The rotation of the rotating electrical machine 1 is transmitted to the clutch 63 via the belt 62 spanned between the driven pulley 65 and the driving pulley 67, and the rotation of the permanent magnet type rotating electrical machine 1 is transmitted to the gear 66 of the gear case 64.

  A stirring blade 61 is fastened to the inner output shaft of the gear case 64, and a washing tub 59 is fastened to the outer output shaft.

  The drive rotation of the permanent magnet type rotating electrical machine 1 is switched by a clutch (rotation transmission switching means) 63. The rotation of the permanent magnet type rotating electrical machine 1 is transmitted to the stirring blade 61 or the washing tub 59 and the stirring blade 61 by switching the clutch (rotation transmission switching means) 63.

  The laundry in the washing tub 59 is washed by the stirring rotation of the stirring blade 61. The laundry in the washing tub 59 is centrifugally dehydrated by the high-speed rotation of the washing tub 59.

  In the dehydration of the laundry, the rotating electrical machine 1 rotates at a high speed, and centrifugal dehydration is performed from the dewatering hole 68 provided in the body of the washing tub 59. Since the washing tub 59 is provided with the balancer 60 in the upper part, abnormal vibrations at the time of centrifugal dehydration when an imbalance occurs due to the deviation of the laundry are alleviated.

  The lid 54 opens and closes an opening provided in the upper part of the washing tub 59 and puts in and out the laundry.

  The control board 69 is provided on the top cover 53, and an operation panel 70 is provided on the surface of the control board 69 so that the washing machine 50 can be operated.

  The water level sensor 71 is disposed on the back side of the top cover 53. The water level sensor 71 communicates with the air chamber of the air trap 73 through the pressure tube 72. The water level of the washing water stored in the outer tub 55 is detected by the water level sensor 71 by a change in water pressure, and the water level information is provided to the control board 69 to control the water supply.

  The water injection case 74 is connected to a water supply hose 76 via a water supply electromagnetic valve 75. The water supply hose 76 is connected to a tap for supplying tap water. The tap water is poured into the washing tub 59 through the water pouring case 74 when the water supply electromagnetic valve 75 is opened.

  The outer tank cover 77 is provided on the upper part of the outer tank 55. Even if tap water flowing out of the water injection case 74 is removed from the outside of the washing tub 59, it is guided by the outer cover 77 and flows out of the machine so as not to wet the floor surface. It is poured into the washing tub 59.

  The drain electromagnetic valve 78 is communicated with a drain outlet provided at the bottom of the outer tub 55 via a drain hose 79. Water used for washing and rinsing is discharged outside the machine through the drainage hose 79 when the drainage solenoid valve 78 is opened.

  A permanent magnet type rotating electrical machine 1 that is a drive source of the above-described vertical washing machine 50 includes a stator 2 and a rotor 3. The stator 2 includes a stator core 4, a plurality of slots 5 (9 in the drawing) provided on the stator core 4, and teeth 6 divided by these slots 5. The armature winding 7 (consisting of a U-phase winding 7A, a V-phase winding 7B, and a W-phase winding 7C) is a concentrated winding wound around the plurality of slots 5. An inner diameter side of the slot 5 is a slot opening 8, and a circular stator slit 9 (9 a and 9 b) is provided on the inner diameter side of the tooth 6.

Further, the inner peripheral surface on the inner diameter side of the tooth 6 is beveled including magnetic pole pieces extending on both sides in the circumferential direction of the tooth 6. When the angle between 9a and 9b of the stator slit 9 is θ1, the angle of the start point of beveling is θ2, and the pitch angle of the teeth 6 is θ3, θ3>θ2> θ1 , where θ1 × 2 = θ2. A relation of θ2 × 2 = θ3 is set.

  In the rotor 3, ferrite magnets 12 are housed in U-shaped magnet insertion holes 11 (six in the drawing) arranged on the outer peripheral side of the rotor core 10, and the rotation is on the outer peripheral side of the ferrite magnet 12. The rotor magnetic pole core 13 of the rotor 3 is connected to the rotor magnetic pole core 13 by a magnetic bridge 14. That is, in the embodiment of the present invention, the permanent magnet type rotating electrical machine 1 has 6 poles and 9 slots.

  Here, although the clearance L1 for magnet insertion is provided in the both ends of the magnet insertion hole 11 and the U-shaped ferrite magnet 12, the value is as small as about 0.1 mm.

  In addition, a d-axis slit 15 formed with a long hole in the radial direction is provided at the center of the rotor magnetic core 13, and a circular q-axis slit 16 is provided on the q-axis. The rotor formed by injection molding is shown in FIG. It is. FIG. 1 is a view cut along the PP line of FIG. 3. The shaft hole 19 is at the center of the rotor core 10, and the shaft 20 is fitted or shrink-fitted into the shaft hole 19. . In FIG. 4, which is a perspective view of FIG. 3, the mold part on the outer periphery of the rotor 3 is 21 and the mold part at one end of the rotor magnetic pole core 13 is 22A, and the mold part 22A and the shaft 23 do not contact each other. It is molded as follows. The same applies to the other mold portion 22B.

  The mold part 21 formed on the magnetic bridge 14 of the q-axis side iron core is connected to the mold parts 22A and 22B. Thereby, the centrifugal strength of the magnetic bridge 14 can be increased.

  Further, the slits 15 and 16 are simultaneously injection-molded to form the mold parts 17 and 18, and the angle θ5 between the slit 15 and the two slits 16 is close to 60 degrees, and the angle θ4 between the slit 16 and the two slits 15 is formed. Is set in the vicinity of 120 °, the mold parts 17 and 18 in the slits 15 and 16 also prevent the rotor magnetic core 13 from jumping out due to centrifugal force.

  FIG. 5 is an RR cross-sectional view of FIG. 1, in which the permanent magnet 12 in the permanent magnet insertion hole 11 is held by the mold portion 17 in the slit 15 and the end mold portions 22A and 22B. When the thickness between the slit 15 and the outer periphery of the rotor is L2, and the thickness between the slit 15 and the permanent magnet insertion hole 11 is L3, both are set to 0.5 mm as the thickness of the electromagnetic steel sheet.

  FIG. 6 is a QQ cross-sectional view of FIG. 1, and a rotor magnetic pole core (not shown) is formed by the mold portion 18 in the slit 16, the mold portion 21 on the q-axis side of the rotor core 10 and the end mold portions 22A and 22B. 13 is held.

  These centrifugal force strengths are calculated in FIG. 9 and calculated with the ferrite magnet 12 inserted into the magnet insertion hole 11. The assumed rotation speed is 10,000 r / min. No. In (1), the thickness of the magnetic steel sheet is 0.5 mm, whereas the basic thickness of the magnetic bridge 14 is 0.4 mm. Therefore, the leakage flux is large and the required magnetic flux amount is insufficient and the characteristics are deteriorated. Therefore, the minimum thickness of the magnetic bridge 14 is 0.2 mm. As a result of the strength calculation, the maximum stress applied to the magnetic bridge 14 was 286 MPa. Generally, the tensile strength of an electromagnetic steel sheet is 360 MPa, and when the start and stop are repeated 1 million times, the tensile strength is reduced to 180 MPa, which is 1/2. That is, no. The structure of (1) is a repetitive load of a washing machine or the like, and if a dehydration process of 10000 r / min or more is carried out, the strength of the rotor core 10 is reduced and cannot be adopted in the washing machine. It is necessary to reduce the rotational speed. That is, if the maximum rotational speed is set to 7000 r / min or less, the centrifugal force strength is acceptable.

  Next, no. The structure (2) is when the thickness of the magnetic bridge 14 is all 0.4 mm. As a result, it has been found that the maximum stress applied to the rotor core 10 is reduced to 244 MPa by increasing the minimum thickness from 0.2 mm to 0.4 mm, but a dehydration process of 10000 r / min or more at the maximum. Can not be used.

  Next, no. (3) No. In the structure (2), the outer periphery and the axial end of the magnetic bridge 14 of the rotor 3 are molded. As a result, the maximum stress was reduced to 223 MPa, and it was found that the rotor outer periphery mold was effective in reducing the stress.

  Next, no. The structure (4) is a case where the reference thickness of the magnetic bridge 14 is 0.5 mm, and the minimum thickness is 0.4 mm by R-cut that is recessed in the middle of the magnetic bridge 14 in an arc shape. As a result, the maximum stress applied to the rotor core 10 was reduced by 221 MPa and 2 MPa. In order to reduce the maximum stress to 180 MPa or less, it is necessary to increase the thickness considerably. In this case, the magnetic flux of the magnet leaks through the magnetic bridge 14 and cannot be adopted from the viewpoint of characteristics. Therefore, it is necessary to reduce the maximum dehydration speed in order to make the maximum stress 180 MPa or less.

  Here, the description has been made assuming that the minimum thickness of the magnetic bridge 14 is 0.2 mm when the thickness of the electromagnetic steel sheet is 0.5 mm. Whether or not the electromagnetic steel sheet can be punched while keeping the thickness 0.2 mm stable is a mold design problem. Although the entire thickness of the magnetic bridge 14 cannot be reduced to 0.2 mm, a part of the magnetic bridge 14 can be reduced to 0.2 mm. Naturally, the thickness of 0.4 mm or 0.5 mm of the magnetic bridge 14 is easier than when 0.2 mm.

  When mold injection molding is performed on the outer periphery of the rotor, if the gap between the stator and the rotor is narrow, it is necessary to reduce the thickness of the mold, so there is a possibility that the mold material will crack when cooled after molding. Yes, even if one cracks, it cannot be commercialized.

  In this embodiment, in order to avoid the above matters, the outermost periphery of the magnetic bridge 14 is separated by 0.76 mm from the outer periphery of the rotor, and a semicircular R-shaped groove 31 having a radius of 0.68 mm is formed on the q-axis. By providing a portion 32 that is recessed in an arc shape toward the inner diameter side on the outer peripheral side of 14, a portion having a basic thickness of 0.4 mm but reduced to 0.2 mm was formed.

  According to the present embodiment, since unevenness is formed on the outer peripheral surface of the magnetic bridge 14, the contact surface area between the molding material and the magnetic bridge 14 is increased, and the strength is improved. For this reason, the minimum thickness part of the magnetic bridge 14 can be formed, the leakage magnetic flux of a permanent magnet can be reduced, and the high output of a rotary electric machine is possible. In addition, since the R groove 31 having a radius of 0.68 mm is provided on the q axis, the armature reaction is reduced. Furthermore, since the R portion 33 is provided on the inner surface side of the magnet insertion hole, a gap is formed between the permanent magnet and the magnet insertion hole, which also prevents cracking of the molding material when cooled after being molded. .

  In other words, since the centrifugal strength of the rotor can be increased by molding the outer peripheral side of the magnetic bridge 14 on the q-axis side, a thin portion is formed in the magnetic bridge 14 to the extent that the strength is allowed, and the leakage flux of the permanent magnet 12 It is possible to improve the motor characteristics by reducing. Therefore, a high-power permanent magnet type rotating electrical machine can be realized even if a U-shaped or V-shaped ferrite magnet is used without using a neodymium magnet.

  FIG. 10 shows a rotor according to still another embodiment of the present invention. The rotor 3 is provided with a V-shaped magnet insertion hole 23 into which a V-shaped permanent magnet 24 is inserted.

  FIG. 11 shows a rotor according to still another embodiment of the present invention. The rotor 3 is provided with an elliptical slit 25 on the q axis, and a mold 26 is provided therein. As can be seen from the figure, when the elliptical slit 25 is enlarged to the shaft hole 19, the magnet magnetic flux and the armature reaction magnetic flux are reduced. Therefore, the length is preferably determined from the characteristics.

  In these embodiments, as a driving method of the vertical washing machine, the rotation of the permanent magnet type rotating electrical machine 1 is performed by the driving pulley 67, the belt 62, the driven pulley 65, the clutch 63, and the gear 66 in the gear case 64. It is transmitted to the stirring blade 61 or the washing tub 59 and the stirring blade 61 by switching.

  Here, since the cooling fan 27 is formed at the shaft end of the permanent magnet type rotating electrical machine 1, the permanent magnet type rotating electrical machine 1 can be used efficiently. That is, if the pulley ratio is 1.9 and the reduction ratio is 7.2, the total reduction ratio is 13.7. When the rated rotational speed of the rotating electrical machine 1 is 1500 r / min, the rotational speed of the stirring blade 61 during washing is approximately 110 r / min, and the rotational speed of the washing tub 59 during dehydration is approximately 790 r / min.

  On the other hand, if the pulley ratio is 2.5 and the reduction ratio is 5.5, the total reduction ratio is the same 13.7. Similarly, if the rated rotational speed of the rotating electrical machine 1 is 1500 r / min, the rotational speed of the stirring blade 61 during washing is approximately 110 r / min, and the rotational speed of the washing tub 59 during dehydration is significantly reduced to approximately 600 r / min. This is disadvantageous for drying laundry.

  Therefore, if the rated rotational speed at the time of dehydration of the rotating electrical machine 1 is 2000 r / min, the rotational speed of the washing tub 59 at the time of dehydration is about 800 r / min, and there is no problem in drying the laundry.

  On the other hand, in the rotating electrical machine 1, the coil temperature gradually increases as the washing time elapses during washing, and cooling is performed only during dehydration. There is no problem if the laundry is done only once, but if it is washed twice, three times, or five times in many places in a large family, the coil start temperature will gradually increase, and consequently the coil temperature that cannot be washed. There is a possibility.

  On the other hand, in the case of the above-described embodiment in which the rated rotational speed at the time of dehydration of the rotating electrical machine 1 can be increased, the coil can be sufficiently cooled before entering the washing operation, so that there is an effect that continuous washing can be performed forever.

  DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type rotary electric machine, 2 ... Stator, 3 ... Rotor, 4 ... Stator iron core, 5 ... Slot, 6 ... Teeth, 7 ... Armature Windings (U phase 7A, V phase 7B, W phase 7C), 8 ... slot opening, 9 ... stator slit, 10 ... rotor core, 11 ... permanent magnet insertion hole, 12 ... Ferrite magnet, 13 ... Magnetic pole core of rotor, 14 ... Magnetic bridge, 15 ... d-axis slit, 16 ... q-axis slit, 17 ... Mold part, 18 ... Mold part, 19 ... shaft hole, 20 ... shaft, 21 ... mold part, 22 ... mold end, 23 ... V-shaped magnet insertion hole, 24 ... V-shaped permanent Magnet, 25 ... elliptical slit, 26 ... mold part, 27 ... cooling fan, 28 ... anti-vibration 50 ... vertical washing machine, 51 ... outer frame, 52 ... outer frame base, 53 ... top cover, 54 ... lid, 55 ... outer tub, 57 ... -Hanging rod, 58 ... Corner support, 59 ... Washing tub, 60 ... Balancer, 61 ... Stirring blade, 62 ... Belt, 63 ... Clutch, 64 ... Gear case, 65 ... driven pulley, 66 ... gear, 67 ... drive pulley, 68 ... dewatering hole, 69 ... control board, 70 ... operation panel, 71 ... water level sensor, 72 ..Pressure tube, 73 ... Air trap, 74 ... Water injection case, 75 ... Water supply solenoid valve, 76 ... Water supply hose, 77 ... Outer tank cover, 78 ... Drainage solenoid valve, 79 ... Drain hose,

Claims (9)

  A permanent magnet is provided in a plurality of permanent magnet insertion holes formed in the rotor core having a stator in which concentrated armature windings are provided so as to surround the teeth in a plurality of slots formed in the stator core. Is a permanent magnet type rotating electrical machine that is rotatably supported on the inner periphery of the stator via a predetermined gap, in the radial direction of the arc-shaped permanent magnet embedded in the rotor core When the central axis is the d-axis and the axis that is 90 degrees away from the central axis is the q-axis, a long d-axis slit in the radial direction is provided in the rotor magnetic core on the rotor outer periphery side of the permanent magnet, and the q-axis side A magnetic bridge formed by recessing a part of the outer peripheral side of the rotor core toward the inner diameter side, and being circular or elliptical on the q axis and between the permanent magnets or on the inner diameter side of the permanent magnet The q-axis slit of the magnetic bridge And the d-axis slit and the q-axis slit are molded by injection molding, and both end sides in the axial direction of the rotor, the d-axis slit, and the q-axis slit are connected by molding. Electric.   The permanent magnet type rotating electrical machine according to claim 1, wherein the permanent magnet is made of a ferrite magnet having a U shape or a V shape.   3. The permanent magnet type rotating electrical machine according to claim 1, wherein a radial width of the magnetic bridge has a portion smaller than a plate width of the rotor core.   4. The permanent magnet type rotating electrical machine according to claim 1, wherein unevenness is provided on an outer peripheral side surface of the magnetic bridge.   5. The permanent magnet type rotating electric machine according to claim 1, wherein a circular stator slit is provided on an inner diameter side of the tooth to form a pole piece extending from the inner diameter side of the tooth toward both sides in the circumferential direction. Further, the permanent magnet type rotating electric machine is characterized in that beveling is applied to the inner peripheral surface of the tooth. 6. The permanent magnet type rotating electrical machine according to claim 5, wherein an angle between the two stator slits is θ1, an angle of the start point of the beveling on both sides in the circumferential direction is θ2, and a pitch angle of the teeth is θ3. , [ Theta] 3> [theta] 2> [theta] 1 .   The permanent magnet type rotating electrical machine according to any one of claims 1 to 6, wherein the permanent magnet type rotating electrical machine has 6 poles and 9 slots.   A vertical washing machine comprising the permanent magnet type rotating electric machine according to any one of claims 1 to 7. 9. The vertical washing machine according to claim 8, wherein a driving pulley is disposed at a shaft end of the permanent magnet type rotating electric machine, and the rotation of the driving pulley is transmitted to the driven pulley via the belt. A vertical washing machine having a drive unit that transmits the torque to a gear in a gear case via a clutch and has a rated rotational speed during dehydration greater than a rated rotational speed during washing.