JP2007089282A - External rotation type permanent magnet motor and washing machine using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lessen wind power noise which occurs at rotation of a rotor in an outer rotation type permanent magnet motor. <P>SOLUTION: In the outer rotation type permanent magnet motor comprising a stator where coils are wound around a plurality of teeth projected radially at equal intervals from the periphery of an annular yoke and a rotor which rotates a rotor core, where permanent magnets are buried in the internal perimetric part of the annular wall of a frame in the shape of a bottomed cylinder, outside the stator, being equipped with a plurality of vanes for coil cooling at the bottom of the frame, the above plurality of vanes are arranged radially at unequal intervals in its circumferential direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an abduction type permanent magnet motor in which a rotor having a magnetic pole incorporating a permanent magnet is rotated around a stator, and more particularly to a technique for reducing wind noise generated when the rotor rotates.

  As a conventional outer rotation type permanent magnet motor, for example, there is one disclosed in Japanese Patent No. 3017953. FIG. 7 is a cutaway perspective view showing an example of such an outer rotation type permanent magnet motor. The abduction-type permanent magnet motor 1 is used, for example, as a drive motor for integrally rotating the stirrer at the time of washing and the stirrer and the rotary tub at the time of dehydration in a dehydrating washing machine.

  The abduction-type permanent magnet motor 1 is composed of a stator 2 formed in a substantially cylindrical shape and a rotor 3 positioned and rotated on the outer periphery thereof. The stator 2 includes an iron part 6 having a ring-shaped yoke part 4 and a large number of teeth 5 projecting radially from the outer peripheral part thereof, a covering member 7 formed and formed so as to cover almost the entire outer surface thereof, A coil 8 wound around each outer periphery of the tooth 5 is provided.

  On the other hand, the rotor 3 is formed of a magnetic body such as an iron plate with a circular main plate portion 10 having a shaft support 9 disposed in the center and an annular wall 11 standing on the outer peripheral edge of the main plate portion 10. An annular rotor core 14 having a plurality of magnetic pole forming permanent magnets 13 incorporated therein is disposed on the inner peripheral portion of the frame 12 (inside the annular wall 11). The rotor core 14 and the frame 12 are integrally formed of a resin 15, and the shaft support 9 and the main plate portion 10 are also integrally formed of a resin 15 and have a flat bottomed cylindrical shape as a whole.

  In such a motor, when the armature current is passed, the temperature of the coil 8 rises. In order to suppress the temperature rise of the coil 8 and each member, a plurality of cooling blades 17 are radially formed around the shaft support 9 on the main plate portion 10 forming the bottom surface of the frame 12 as shown in the plan view of the rotor 3 in FIG. It is arranged upright. Further, ventilation holes 18 communicating with the outside are provided on both sides of the blade 17. In order to ensure the height of the blade 17, a step portion 19 is provided at a portion where the main plate portion 10 and the annular wall 11 are connected.

  Incidentally, in an abduction-type permanent magnet motor that is required to be thin like a washing machine motor, it is required to shorten the axial distance between the cooling blade 17 and the coil 8 of the stator 2. If the axial distance is shortened in response to this, air turbulence occurs when the cooling blade 17 passes over the coil 8. In particular, when the coil 8 is of the concentrated winding method, there is a gap (space) between adjacent coils, so that the atmospheric pressure fluctuation in the rotor 3 before and after the blades 17 pass over the coil 8 becomes large. A large turbulent flow is generated. Turbulence creates wind noise. Wind noise increases as the motor speed increases.

When the blades 17 provided on the main plate portion 10 are arranged at equal intervals in the circumferential direction and the number of blades and the number of coils have a common divisor, the number of turbulences equal to the common divisor is 1 in the rotor 3. It occurs as many times as the number of coils during rotation. Accordingly, when the blades 17 are arranged in such a manner, wind noise (wind noise) due to turbulent flow is increased.
Japanese Patent No. 3017953

  This invention is made | formed in view of this situation, The subject is to reduce the wind noise generated in the case of rotation of the rotor in an abduction type permanent magnet motor.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a stator having coils wound around the outer periphery of a plurality of teeth projecting radially from the outer periphery of the annular yoke portion, and a bottomed cylindrical frame A rotor core having a permanent magnet embedded in the inner peripheral surface of the annular wall, and a rotor that has a plurality of blades for cooling the coil at the bottom of the frame and rotates on the outside of the stator. In the magnet motor, the plurality of blades are arranged radially from the rotor center at non-uniform intervals in the circumferential direction.

  Thus, if the blades provided at the bottom of the frame of the abduction-type permanent magnet motor are arranged at uneven intervals in the circumferential direction, the timing of the generation of aerodynamic noise when the blades pass over the coil can be set to one rotation time of the rotor. Can be dispersed within. As a result, an effect of reducing generated noise can be obtained.

  Hereinafter, an example in which an abduction type permanent magnet motor (hereinafter simply referred to as an abduction type motor) according to an embodiment of the present invention is applied to the motor shown in FIG. To do. An abduction motor 1 shown in FIG. 7 includes a stator 2 and a rotor 3 that is positioned on the outer periphery and rotates.

  The stator 2 mainly includes an iron core 6 and a coil 8 and is formed in a substantially cylindrical shape as a whole. Among them, the iron core 6 is formed by laminating a large number of silicon steel plates, which are magnetic bodies punched into a predetermined shape, for example, and has a configuration having an annular yoke portion 4 and a large number of teeth 5 projecting radially from the outer periphery thereof. It has become. A covering member 7 made of synthetic resin, which is an electrical insulating material, is provided on almost the entire outer surface of the yoke portion 4 and the teeth 5 by molding. In addition, a plurality of attachment portions 20 are integrally formed on the covering member 7 so as to be positioned on the inner peripheral portion of the yoke portion 4. This attachment part 20 is utilized when attaching the stator 2 to a mechanism part such as a washing machine. Each tooth 5 has a coil 8 wound around each outer periphery of the covering member 7, and the stator 2 is configured as described above.

  On the other hand, the rotor 3 mainly comprises a frame 12, a rotor core 14, and a permanent magnet 13. Among them, the frame 12 is erected from a circular main plate portion 10 in which the shaft support 9 is arranged at the center portion, a step portion 19 formed on the outer peripheral edge thereof, and the step portion 19 as shown in FIG. It has an annular wall 11 and forms a flat, covered cylinder as a whole. The frame 17 is formed by pressing, for example, an iron plate that is a magnetic material.

  A rotor core 14 is disposed in a space surrounded by the inner periphery of the frame 12 (inside the annular wall 11) and the stepped portion 19. The rotor core 14 is configured by laminating a large number of iron plates, for example, which are magnetic bodies punched in a substantially annular shape. A large number of magnet insertion holes 21 are provided on the inner peripheral side of the rotor core 14, and the permanent magnets 13 are inserted therein, thereby forming a large number of magnetic poles 22 arranged in an annular shape. The magnetic pole 22 faces the tip of each tooth 5 of the stator 2 through a slight gap. The frame 12, the rotor core 14, and the permanent magnet 13 are integrally coupled by a resin 15.

  A shaft support 9 to which a rotation shaft (not shown) is inserted and fixed is arranged at the center of the main plate portion 10 of the frame 12. The shaft support 9 and the main plate portion 10 are also integrally coupled by a resin 15. A plurality of cooling blades 17 and cooling holes 18 for cooling the coil 8 of the stator 2 are formed in a portion between the step portion 19 of the main plate portion 10 and the shaft support 9, and the rotation is performed as described above. Child 3 is configured.

  Next, the configuration of the cooling blades 17 and the ventilation holes 18 provided in the main plate 10 that forms the bottom of the frame 12 will be described. FIG. 1 is a plan view of the rotor 3 according to the first embodiment, and corresponds to FIG. 8 described in “Background Art”. As shown in FIGS. 7 and 1, the cooling blades 17 are provided between the stepped portion 19 of the main plate 10 and the shaft support 9 so as to stand on the main plate 10 in a radial manner around the shaft support 9. Yes. And the ventilation hole 18 is provided in the bottom part of the said frame 12 which hits the both sides of each blade | wing 17. FIG. The blade 17 has a height that does not interfere with the coil 8 of the stator 2 during rotation. The step portion 19 also serves to ensure the height of the blade 17.

  The configuration of the arrangement of the blades 17 and the ventilation holes 18 provided in the main plate portion 10 shown in FIG. 1 is different from the configuration of the main plate portion 10 of FIG. 8 according to the prior art in the interval between two adjacent blades 17. The main plate 10 in FIGS. 1 and 8 is an example where the number of blades 17 is twelve. In the main plate portion 10 of FIG. 7 according to the prior art, the blades 17 are arranged radially at equal intervals, that is, at intervals of 30 °. On the other hand, in the main plate portion 10 shown in FIG. 1 of the present embodiment, the two adjacent blades 17 are arranged so that the intervals are not uniform.

  The plurality of coils 8 provided on the stator 2 are arranged radially from the rotation center. When the coil 8 is wound by the concentrated winding method, a gap (space) exists between adjacent coils. Before and after one blade 17 passes over one coil, there is a gap between them, so that a change in atmospheric pressure occurs in the rotor 3 and a turbulent flow passing between the coils occurs.

  As an example, it is assumed that the number of coils 8 is 36 and is arranged at equal intervals of 10 °, and the number of blades 17 is twelve. Then, 12 turbulent flows are generated as a whole between the blade 17 and the coil 8 while the rotor 3 is rotated by 10 ° which is the interval between the coils.

  Here, it is assumed that twelve blades 17 are provided at equal intervals of 30 ° as shown in FIG. In this case, in a state where one certain blade 17 is located directly below one coil, the other 11 blades 17 are also located directly below the other coils at the same time. That is, the positional relationship between each blade 17 and the coil 8 immediately above it (hereinafter referred to as the positional phase relationship) is the same for all twelve blades 17. For this reason, the phases of the twelve turbulent flows generated while the blades 17 are rotated by 10 ° are aligned, and a large wind noise (wind noise) is generated as a whole. This large wind noise is generated 36 times equal to the number of coils 8 during one rotation of the stator 2 and generates a large wind noise.

  On the other hand, in the main plate portion 10 shown in FIG. 1 of the present embodiment, 12 blades 17 are 33 °, 29 °, 32 °, 31 °, 28 °, 30 ° in order clockwise from the blade 17a in the drawing. They are arranged at non-uniform intervals such as 31.5 °. The intervals are set such that none of the other 11 blades 17 is positioned directly below the coils in a state where any one blade 17 is positioned directly between the coils. That is, the phase relationships of the positions of the blades 17 and the coil 8 immediately above the blades 17 are all set to be different.

  Thus, when the positional phase relationship is different, the generation timings of the twelve turbulent flows generated while the blades 17 are rotated by 10 ° are all different. While the stator 2 makes one rotation, 36 × 12 turbulent flows are generated, but all of them are generated at different timings and only one turbulent flow is generated at the same time. Two or more turbulent flows do not occur at the same time, and small turbulent flows with shifted timings occur almost continuously. For this reason, the wind noise is reduced by averaging, and the wind noise is reduced.

  FIG. 2 shows a plan view of the rotor 3 according to the second embodiment. The number of blades 17 in the rotor 3 of FIG. 2 is 11, and they are arranged radially at equal intervals (32.7 ° intervals). The number of coils 8 of the stator 2 is assumed to be 36. Thus, if the number of blades 17 is the number 11 that does not have a common divisor of 1 or more with respect to the number of 36 coils, the phase relationship between the aforementioned positions of each blade 17 and the coil 8 immediately above it is all. It will be different. Accordingly, in this case as well, as in the case of the first embodiment, all 36 × 11 turbulent flows generated during one rotation of the stator 2 are generated at different timings. Accordingly, in this case as well, the effect of reducing wind noise is obtained as in the case of the first embodiment.

  FIG. 3 shows the number of occurrences of turbulence during one rotation of the rotor 3 and the maximum number of turbulences generated simultaneously when the number of coils 8 is 36 and the number of blades 17 is changed. . Since the phase relationships of the positions described above are aligned, the number of occurrences when a plurality of turbulent flows occur simultaneously at the same timing is counted as one. The plurality of blades 17 are arranged radially at equal intervals.

  As is apparent from FIG. 3, when the number of the coils 8 is 36, when the number of blades 17 is 11, 7, and 5 which do not have a common divisor other than 1 with respect to 36, simultaneously. The maximum number of turbulences generated is 1. The number of occurrences of turbulent flow is a large number of 36 × 11, 36 × 7, and 36 × 5, respectively. That is, a low level wind noise is generated many times.

  FIG. 4 compares measured values of the level of wind noise when the motor is rotated at 1400 rpm when the number of blades 17 is 12, 11, and 6. When twelve blades 17 are arranged at equal intervals, turbulent flow occurs 36 times per rotation of the rotor, and the frequency thereof is 840 Hz (= 36 × 1400/60). The noise harmonic level of 840 Hz is −13.03 dB when the blade 17 is used. On the other hand, when it is 11 pieces, it is -15.32 dB, and when it is 6 pieces, it is -15.61 dB, indicating that a noise reduction effect of -2.3 dB and -0.3 dB can be obtained, respectively. Yes.

  As a third embodiment, when the coil 8 provided on the stator 2 is configured by a three-phase concentrated winding system, the number of blades 17 is (3n ± 1) (where n is 1 or more). Integer). That is, when n = 2, the number of blades 17 is set to 7 or 5. When n = 3, the number of blades 17 is 10 or 8. When n = 4, the number of blades 17 is 13 or 11.

  In the case of three phases, the number of coils 8 is also a multiple of three. In this case, if the number of blades 17 is also a multiple of 3, the number of blades 17 in which the above-described positional relationships between the blades 17 and the coil 8 immediately above the blades 17 are increased, and the wind noise increases. Therefore, wind noise can be reduced by setting (3n ± 1) (where n is an integer other than 1) as described above so that the number of blades 17 is not a multiple of three.

  Actually, when the number of the coils 8 is 36 and the number of the blades 17 is set to 5, 7, 11, or 13 according to the above calculation formula, the three phases are generated simultaneously as shown in FIG. 3 described above. The maximum turbulence number is 1, and wind noise is reduced. Even when the number of blades 17 is set to 8, 10 according to the above calculation formula, the wind noise can be reduced to a considerably low level.

  FIG. 5 is a plan view of the rotor 3 according to the fourth embodiment. The rotor 3 in FIG. 5 is obtained by providing each blade 17 in FIG. 2 of the second embodiment obliquely with respect to the radial direction. The plurality of coils 8 of the stator 2 are arranged radially in the radial direction. Accordingly, gaps (spaces) between adjacent coils also exist radially in the radial direction. For this reason, if each blade | wing 17 by the side of the rotor 3 is provided diagonally with respect to radial direction, each blade | wing 17 will cross | intersect the clearance gap between coils diagonally. In this case, some or all of the blades arranged obliquely may be used.

As described above, when the rotor 3 rotates, if the blade 17 and the gap between the coils cross obliquely, the air pressure in the rotor 3 generated when the blade 17 passes through the gap between the coils or the coil. The fluctuation becomes smooth. As a result, an effect of reducing the level of wind noise generated can be obtained.
The idea of providing each blade 17 obliquely may be applied to the first and third embodiments, and the same effect can be obtained when applied to the rotor 3 shown in FIG. can get.

  FIG. 6 is a plan view of the rotor 3 according to the fifth embodiment. The rotor 3 in FIG. 6 has a plurality of types of radial lengths of the blades 17 in FIG. 2 of the second embodiment. In FIG. 6, there are three types of radial lengths of the blades 17. When the radial lengths of the blades 17 are configured in a plurality of types in this way, the number of blades 17 that simultaneously pass on the coil within the time required for the rotor 3 to rotate once is reduced in the radial direction. Therefore, there is an effect that the level of wind noise generated by the smooth fluctuation of the atmospheric pressure in the rotor 3 is reduced.

  In addition, the idea which makes the radial direction length of this blade | wing 17 into multiple types may be applied to 1st, 3rd, 4th embodiment, and also in the rotor 3 shown in FIG. 8 which is a prior art. Even if applied, the same effect can be obtained.

  As described above, the abduction-type permanent magnet motor employing the rotor of each embodiment as described above generates less noise. Therefore, if it is used in a washing machine and a washing machine dryer including this, a quiet washing machine with less noise is obtained. Can be realized.

It is a top view of the rotor which concerns on 1st Embodiment. It is a top view of the rotor which concerns on 2nd Embodiment. It is the figure which calculated the number of the blade | wings in the rotor which concerns on 2nd Embodiment, the frequency | count of turbulent flow generation, and the maximum turbulent flow number which generate | occur | produce simultaneously. It is a figure explaining the noise reduction of the rotor which concerns on 2nd Embodiment. It is a top view of the rotor which concerns on 4th Embodiment. It is a top view of the rotor which concerns on 5th Embodiment. It is a fracture perspective view of an example of an abduction type permanent magnet motor. FIG. 2 is a view corresponding to FIG.

Explanation of symbols

  In the drawings, 1 is an outer rotation type permanent magnet motor, 2 is a stator, 3 is a rotor, 4 is a yoke portion, 5 is a tooth, 8 is a coil, 9 is a shaft support, 12 is a frame, 11 is an annular wall, Reference numeral 13 denotes a permanent magnet, 14 denotes a rotor core, 17 denotes a cooling blade, and 18 denotes a ventilation hole.

Claims (7)

A stator in which a coil is wound around the outer periphery of teeth projecting radially from the outer peripheral portion of the annular yoke portion at equal intervals, and a rotor core having a permanent magnet embedded in the inner peripheral surface of the annular wall of the bottomed cylindrical frame In the abduction type permanent magnet motor comprising a plurality of blades for cooling the coil at the bottom of the frame and a rotor rotating outside the stator,
An abduction type permanent magnet motor, wherein the plurality of blades are arranged radially at non-uniform intervals in the circumferential direction.   2. The external rotation type permanent magnet motor according to claim 1, wherein the number of the blades is a number that does not have a common divisor other than 1 and the number of the coils provided in the stator, and the blades are arranged in the circumferential direction. An abduction-type permanent magnet motor characterized by being radially arranged at equal intervals.   2. The external rotation type permanent magnet motor according to claim 1, wherein the coil provided in the stator is configured by a three-phase concentrated winding system, and the blade has an integer of 1 or more (3n ± 1) The abduction-type permanent magnet motor is characterized in that the blades are radially arranged at equal intervals in the circumferential direction.   4. An abduction-type permanent magnet motor according to claim 1, wherein a part or all of each blade is provided obliquely with respect to the radial direction.   The abduction-type permanent magnet motor according to any one of claims 1 to 4, wherein the plurality of blades have a plurality of radial lengths.   6. An abduction-type permanent magnet motor according to claim 1, wherein a ventilation hole is provided in a bottom portion of the frame that contacts both sides of each blade. A washing machine using the abduction-type permanent magnet motor according to any one of claims 1 to 6 for driving a rotary tub or a pulsator.

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