JP6558076B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine in which a stator is disposed inside an outer rotor.

  Conventionally, as this type of rotating electric machine (that is, an electric motor or a generator), for example, there is one described in Patent Document 1. The rotating electrical machine described in Patent Document 1 is a so-called outer rotor type electric motor, and includes an outer rotor in which a permanent magnet is fixed on the inner peripheral side of a cylindrical portion of a yoke, and a stator in which a coil is wound around an iron core. And the outer rotor is rotated by electromagnetic force generated by the stator.

JP 2013-176202 A

  It is known that an outer rotor type electric motor generates noise by exciting resonance when the frequency of electromagnetic force generated by the stator matches the resonance frequency of the outer rotor.

  Here, the distribution of the electromagnetic force (that is, the exciting force) generated by the stator is elliptical (that is, the circular secondary mode).

  Further, the yoke of the outer rotor is made as axisymmetric as accurately as possible in order to prevent eccentricity and distortion of electromagnetic force distribution. The outer rotor having an axisymmetric yoke becomes an antinode of vibration at any position in the rotational direction, and thus becomes an elliptical resonance mode in which the positions of the antinodes and nodes are not fixed (that is, the circular secondary mode), and electromagnetic The force was converted to 100% vibration, and there was a problem that the noise due to the outer rotor resonance became extremely large.

  In view of the above points, an object of the present invention is to reduce noise due to resonance of an outer rotor in an outer rotor type rotating electrical machine.

In order to achieve the above object, according to the first aspect of the present invention, a disk-shaped yoke plate portion (611) coupled to the rotation shaft (5) and a cylinder extending in the rotation axis direction from the outer edge portion of the yoke plate portion. An outer rotor (6) having a cylindrical yoke cylindrical portion (612), and a stator (7) disposed inside the outer rotor, wherein the yoke plate portion has an antinode and a node in a resonance mode of the outer rotor. Resonance control units (B1, C1) for fixing the position of
The resonance control part is a different rigidity part (B1) having a rigidity different from that of the remaining part of the yoke plate part provided in at least one place in the rotating electric machine rotation direction of the yoke plate part. It has a different rigid part and a standard rigid part whose rigidity is lower than the different rigid part,
For a rotating electrical machine in an annular m-order resonance mode in which the positions of the antinodes and nodes are not fixed, the yoke plate portion is virtually divided into 2 m regions at equal pitches along the rotating electrical machine rotation direction. The different rigid portions and the standard rigid portions are alternately arranged in each virtual region .

  According to this, as the resonance mode of the outer rotor, two annular m-order modes in which the positions of the antinodes and nodes are fixed and the antinodes and nodes are displaced from each other in the rotating electric machine rotation direction appear. As described above, the positions of the antinodes and nodes are fixed, and the antinodes and nodes are displaced in the rotational direction of the rotating electrical machine, so that part of the electromagnetic force is not converted into vibration in the frequency range near the resonance frequency, and the outer rotor Noise due to resonance is reduced.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is front sectional drawing of the rotary electric machine which concerns on 1st Embodiment of this invention. It is the II arrow directional view of the yoke in the rotary electric machine of FIG. It is a figure which shows distribution of the electromagnetic force which the stator of FIG. 1 generate | occur | produces. It is a figure which shows the transfer function at the time of the electromagnetic force of the stator in the conventional rotary electric machine being transmitted to a yoke. It is a figure which shows the transfer function at the time of the electromagnetic force of the stator in the rotary electric machine which concerns on 1st Embodiment being transmitted to a yoke. It is a figure which shows the relationship between the vibration response level and frequency of an outer rotor in the rotary electric machine of FIG. 1 and the conventional rotary electric machine. It is a figure similar to FIG. 2 which shows the modification of the yoke in the rotary electric machine which concerns on 1st Embodiment. It is a perspective view of the yoke in the rotary electric machine which concerns on 2nd Embodiment of this invention. It is the IX arrow directional view of the yoke of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. In the present embodiment, an outer rotor type electric motor that is in an annular secondary resonance mode in which the positions of the antinodes and nodes are not fixed is provided with a different rigidity portion B1 described later.

  As shown in FIGS. 1 and 2, the rotating electrical machine of the present embodiment is an outer rotor type electric motor, and the first bearing 2 is mounted on the inner peripheral side of the cylindrical portion of the base 1. A cylindrical bearing holder 3 is fitted on the peripheral side, and a second bearing 4 is mounted on the inner peripheral side of the bearing holder 3. The rotating shaft 5 is rotatably supported by the first bearing 2 and the second bearing 4.

  An outer rotor 6 is press-fitted and fixed to the rotary shaft 5. The outer rotor 6 includes a metal yoke 61 and a permanent magnet 62 fixed to the inner peripheral side of the yoke 61. The outer rotor type electric motor of this embodiment has 5 pole pairs (that is, 5 permanent magnets 62 and 10 magnetic poles).

  The yoke 61 includes a disc-shaped yoke plate portion 611 having a rotary shaft 5 press-fitted at the center thereof and extending in a direction orthogonal to the rotary shaft, and a cylindrical yoke cylindrical portion extending from the outer edge portion of the yoke plate portion 611 in the rotational axis direction. 612 and has a bottomed cylindrical shape.

  Four circular through holes 611a are formed in the yoke plate portion 611 at equal intervals of 90 ° along the circumferential direction of the yoke 61 (in other words, the rotating electric machine rotation direction).

  Here, the yoke plate portion 611 is virtually divided into eight regions (that is, twice the number of the through holes 611a) at an equal pitch along the rotating electric machine rotation direction. More specifically, it is divided into a first region B1 including the through hole 611a and a second region B2 not including the through hole 611a. In FIG. 2, the first region B1 is shown in a twill pattern for the sake of convenience in order to clarify the respective ranges of the first region B1 and the second region B2.

  The rigidity of the first region B1 including the through hole 611a is lower than the rigidity of the second region B2 not including the through hole 611a. Hereinafter, the first region B1 is referred to as a different rigid portion B1, and the second region B2 is referred to as a standard rigid portion B2. Four different rigid portions B1 are arranged at an equal pitch along the rotating electric machine rotation direction.

  In the outer rotor type electric motor that does not include the different rigidity portion B1, when the resonance mode is the m-th order of the annular shape, m or 2m different rigidity portions B1 are provided from the viewpoint of the noise reduction effect due to resonance. desirable. Incidentally, in the present embodiment, 2m (that is, four) different rigid portions B1 are provided.

  The yoke cylindrical portion 612 is not formed with a hole such as the through hole 611a of the yoke plate portion 611. Therefore, the yoke cylindrical part 612 has uniform rigidity in each part in the rotating electric machine rotation direction.

  A stator 7 in which a coil 72 is wound around an iron core 71 is fixed to the outer peripheral side of the cylindrical portion of the base 1. Further, the stator 7 is disposed inside the yoke cylindrical portion 612.

  In the outer rotor type electric motor configured as described above, when electric power is supplied to the coil 72, the stator 7 generates an electromagnetic force (see FIG. 3), and the rotating shaft 5 and the outer rotor 6 receive the rotating electromagnetic force. Rotate. 3 is a circumferential angle (that is, a circumferential position) in the stator 7.

  Here, when the rigidity of the entire yoke is uniform in each part in the rotating electric machine rotation direction as in the conventional outer rotor type electric motor, vibration occurs at any position in the rotating electric machine rotation direction in the yoke. As shown in FIG. 4, the transfer function when the electromagnetic force of the stator is transmitted to the yoke is constant regardless of the circumferential angle θ (that is, the circumferential position) in the yoke.

  On the other hand, in the present embodiment, since the different rigidity portion B1 becomes a vibration node, the transfer function when the electromagnetic force of the stator 7 is transmitted to the yoke 61 is the circumferential direction in the yoke 61 as shown in FIG. It fluctuates with a change in the angle θ (that is, the circumferential position).

  When the rigidity of the entire yoke is uniform in each part in the rotating electric machine rotation direction as in a conventional outer rotor type motor, the frequency of the electromagnetic force generated by the stator and the outer rotor are shown in FIG. Large vibrations are excited when the resonance frequencies of the two coincide.

  On the other hand, when four different rigid portions B1 are arranged at an equal pitch along the rotating electric machine rotation direction as in the present embodiment, the resonance mode of the outer rotor 6 is such that the positions of the belly and the node are as shown in FIG. Two circular secondary modes are formed which are fixed and the positions of the antinodes and nodes are shifted from each other by 45 ° in the rotating electric machine rotation direction. In addition, the circular secondary mode appears at two resonance frequencies as shown by a solid line in FIG.

  In this way, the positions of the abdomen and nodes are fixed and the positions of the abdomen and nodes are shifted from each other in the rotational direction of the rotating electrical machine (that is, an elliptical double root with the positions of the abdomen and nodes fixed) Part of the electromagnetic force is not converted into vibration in the frequency range near the resonance frequency, and noise due to resonance of the outer rotor 6 is reduced.

  Further, the magnetic flux passing through the outer rotor 6 mainly passes through the yoke cylindrical portion 612 and hardly passes through the yoke plate portion 611. Therefore, when the different rigidity portion B1 is provided in the yoke cylindrical portion 612, the amount of magnetic flux passing through the yoke cylindrical portion 612 is reduced and the generated torque of the motor is reduced. When B1 is provided on the yoke plate portion 611, the amount of magnetic flux passing through the yoke cylindrical portion 612 is not reduced, and the generated torque of the electric motor is not reduced.

  Moreover, in this embodiment, one arbitrary other rigid part B1 is arrange | positioned in the position which shifted | deviated 180 degree | times to the rotary electric machine rotation direction with respect to arbitrary different rigid parts B1 among several different rigid parts B1. Therefore, the weight balance in the rotation direction of the outer rotor 6 is achieved, and vibration and noise due to unbalance are prevented.

  Further, when four different rigid portions B1 are arranged at an equal pitch along the rotating electric machine rotation direction as in the present embodiment, the difference between the two resonance frequencies in the outer rotor 6 can be maximized. .

  Note that, as in the modification shown in FIG. 7, the yoke plate 611 may be provided with a cooling hole 611 b through which cooling air for cooling the permanent magnet 62 passes. The cooling holes 611b are arc-shaped long holes, and are provided in the same number as the number of pole pairs (that is, five).

  Further, in an outer rotor type motor that does not include the different rigidity portion B1, when the resonance mode is an annular third order, three or six different rigidity portions B1 are provided from the viewpoint of noise reduction effect due to resonance. desirable.

  In this case, the resonance mode of the outer rotor 6 is two circular tertiary modes in which the positions of the antinodes and nodes are fixed and the antinodes and nodes are displaced from each other in the rotating electric machine rotation direction. Appears at two resonant frequencies. As a result, part of the electromagnetic force is not converted into vibration in the frequency range near each resonance frequency, and noise due to resonance of the outer rotor 6 is reduced.

(Second Embodiment)
A second embodiment of the present invention will be described. Only the parts different from the first embodiment will be described below.

  In the present embodiment, an outer rotor type electric motor that is in an annular secondary resonance mode in which the positions of the antinodes and nodes are not fixed is provided with a different weight portion C1 described later.

  As shown in FIGS. 8 and 9, the outer surface of the yoke plate portion 611 has a protruding shape at an equal pitch of 90 ° along the circumferential direction of the yoke plate portion 611 (in other words, the rotating electric machine rotation direction). Four circular weights 611c are provided. The weight 611c may be formed integrally with the yoke plate portion 611. Further, a weight 611c formed separately from the yoke plate portion 611 may be joined to the yoke plate portion 611.

  Here, the yoke plate portion 611 is virtually divided into eight regions (that is, twice the number of weights 611c) at an equal pitch along the rotating electric machine rotation direction. More specifically, it is divided into a first region C1 including the weight 611c and a second region C2 not including the weight 611c. In FIG. 9, in order to clarify each range of the first region C1 and the second region C2, the first region C1 is shown in a cross pattern for convenience.

  When the weight for each predetermined range in the rotating direction of the rotating electric machine in the yoke plate portion 611 (in this embodiment, the weight for each region virtually divided into eight in the yoke plate portion 611) is set as the predetermined range weight, The weight of the first region C1 including 611c is heavier than the weight of the second region C2 not including the weight 611c. Hereinafter, the first region C1 is referred to as a different weight part C1, and the second region C2 is referred to as a standard weight part C2.

  When four weights 611c are arranged at an equal pitch along the rotating electric machine rotation direction as in the present embodiment, the resonance mode of the outer rotor 6 is such that the positions of the antinodes and nodes are fixed and the antinodes and nodes are positioned relative to each other. Two circular secondary modes shifted by 45 ° in the rotating electric machine rotation direction are formed, and the circular secondary modes appear at two resonance frequencies. Therefore, noise due to resonance of the outer rotor 6 is reduced.

  Further, when the different weight portion C1 including the weight 611c is provided in the yoke plate portion 611 as in the present embodiment, the amount of magnetic flux passing through the yoke cylindrical portion 612 is not reduced, and the generated torque of the motor is not reduced.

  In the present embodiment, one of the different weight parts C1 is arranged at a position shifted by 180 ° in the rotating electric machine rotation direction with respect to an arbitrary different weight part C1 among the plurality of different weight parts C1. Therefore, the weight balance in the rotation direction of the outer rotor 6 is achieved, and vibration and noise due to unbalance are prevented.

  Further, when four different weight portions C1 are arranged at an equal pitch along the rotating electric machine rotation direction as in this embodiment, the difference between the two resonance frequencies in the outer rotor 6 can be maximized. .

  In addition, the outer rotor type electric motor may be used as a blower by bonding a resin blower fan to the outer peripheral side of the yoke cylindrical portion 612. In this case, if the weight 611c is provided on the outer peripheral surface of the yoke cylindrical portion 612, the blower fan and the weight 611c interfere with each other. On the other hand, when the weight 611c is provided on the yoke plate portion 611 as in this embodiment, the blower fan and the weight 611c do not interfere with each other.

  Also in this embodiment, a cooling hole (see FIG. 7) through which cooling air for cooling the permanent magnet 62 passes may be provided in the yoke plate portion 611.

  Further, in the outer rotor type motor that does not include the different weight portion C1, when the resonance mode is an annular third order, three or six different weight portions C1 are provided from the viewpoint of noise reduction effect due to resonance. desirable.

  In this case, the resonance mode of the outer rotor 6 is two circular tertiary modes in which the positions of the antinodes and nodes are fixed and the antinodes and nodes are displaced from each other in the rotating electric machine rotation direction. Appears at two resonant frequencies. As a result, part of the electromagnetic force is not converted into vibration in the frequency range near each resonance frequency, and noise due to resonance of the outer rotor 6 is reduced.

(Other embodiments)
In each of the above embodiments, a plurality of different rigid portions B1 or different weight portions C1 are provided. However, one different rigid portion B1 or different weight portion C1 may be provided. Even in this case, the resonance mode of the outer rotor 6 is two annular m-order modes in which the positions of the antinodes and nodes are fixed and the antinodes and nodes are displaced from each other in the rotating electric machine rotation direction. Noise is reduced.

  Further, in each of the above-described embodiments, the different rigidity portion B1 or the different weight portion C1 is arranged at an equal pitch along the rotating electric machine rotation direction, but at a position different from the position of the different rigidity portion B1 or the different weight portion C1. Further, the different rigid portion B1 or the different weight portion C1 may be formed.

  However, in this case, the number of different rigid portions B1 or different weight portions C1 to be further formed is different from the number of different rigid portions B1 or different weight portions C1 arranged at equal pitches (that is, four). In this way, the two resonance frequencies of the outer rotor 6 can be reliably varied.

  In addition, from the viewpoint of the noise reduction effect due to resonance, when providing the different rigidity portion B1 or the different weight portion C1 in the outer rotor type electric motor that is in a circular secondary resonance mode in which the positions of the antinodes and nodes are not fixed, It is desirable to provide two or four different rigid portions B1 or different weight portions C1. Further, when the different rigidity portion B1 or the different weight portion C1 is provided in the outer rotor type electric motor that is in an annular third resonance mode in which the positions of the belly and the node are not fixed, the different rigidity portion B1 or the different weight portion C1 is set to 3 It is desirable to provide one or six. In other words, it is desirable to provide m or 2m different rigid portions B1 or different weight portions C1 for an outer rotor type electric motor that is in an annular m-order resonance mode in which the positions of the antinodes and nodes are not fixed.

  Further, although the different rigidity portion B1 or the different weight portion C1 is arranged at an equal pitch along the rotating electric machine rotation direction, the maximum noise reduction effect can be obtained. However, the yoke plate portion 611 is arranged along the rotating electric machine rotation direction. Even if the different rigid part B1 or the different weight part C1 is virtually divided into 2 m areas on the pitch, and one different rigid part B1 or different weight part C1 is provided at an appropriate position of each divided virtual area, in other words, Even if the weight parts C1 are arranged at unequal pitches along the rotating electric machine rotation direction, a noise reduction effect can be obtained.

  In addition, since a rotating electrical machine having 10 magnetic poles and 12 slots is likely to induce a secondary secondary resonance mode, the present invention is suitable for a rotating electrical machine having 10 magnetic poles and 12 slots. is there.

  Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims.

  Further, the above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible.

  In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes.

  Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case.

  Further, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the component, etc., the shape, unless otherwise specified and in principle limited to a specific shape, positional relationship, etc. It is not limited to the positional relationship or the like.

5 Rotating shaft 6 Outer rotor 7 Stator 611 Yoke plate part 612 Yoke cylindrical part B1 Different rigidity part (resonance control part)
C1 Different weight part (resonance control part)

Claims (2)

An outer rotor (6) having a disk-shaped yoke plate portion (611) coupled to the rotation shaft (5) and a cylindrical yoke cylindrical portion (612) extending in the rotation axis direction from an outer edge portion of the yoke plate portion; ,
A stator (7) disposed inside the outer rotor,
The yoke plate part is provided with a resonance control part (B1, C1) for fixing the positions of the antinodes and nodes in the resonance mode of the outer rotor,
The resonance control part is a different rigidity part (B1) having a rigidity different from that of the remaining part of the yoke plate part provided in at least one place in the rotating electric machine rotation direction of the yoke plate part,
The yoke plate portion has the different rigidity portion and a standard rigidity portion that is higher in rigidity than the different rigidity portion,
The yoke plate portion is virtually divided into 2 m regions at equal pitches along the rotating electric machine rotation direction, and the different rigid portions and the standard rigid portions are alternately arranged in the divided virtual regions. rotating electric machine, characterized in that there. The rotating electrical machine according to claim 1, wherein the different rigidity portion includes a hole (611a) provided in the yoke plate portion .

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