JP2017169308A - Stator for rotating electrical machine - Google Patents

Abstract

[PROBLEMS] To reduce torque ripple in a rotating electrical machine such as a motor.
A rotating electrical machine stator has a laminated core in which a plurality of divided cores are laminated. In one laminated core 24, the tooth portion 28 constituting the divided core 22 is skewed. The skew phase difference of the tooth portion 28 differs in the stacking direction. That is, the skew phase difference is maximum at the maximum torque current advance angle (best advance angle) position at which the torque of the motor 12 is maximum, and decreases as the distance from the best advance angle position increases. The change in the skew phase difference is preferably gradual.
[Selection] Figure 4

Description

  The present invention relates to a stator for a rotating electrical machine that has an annular shape and in which a rotor is rotatably inserted.

  A rotating electrical machine such as a motor includes an annular stator and a rotor inserted into the hollow interior of the stator. The stator has an electromagnetic coil that generates a magnetic field and a core for winding the electromagnetic coil, while the rotor has a permanent magnet held by a rotating holder. In the case of a motor, an alternating magnetic field is generated by applying an alternating current to the electromagnetic coil, and the rotor rotates as the alternating magnetic field and the permanent magnet repeat attraction and repulsion.

  Here, as the core, for example, a core obtained by stacking a plurality of annular shaped pieces produced by punching electromagnetic steel sheets is used. That is, in the laminate, hereinafter, one piece is referred to as a “core member”, and a laminate obtained by laminating a plurality of the core members is referred to as a “laminated core”.

  The core member has a yoke portion that circulates in an annular shape and a teeth portion that protrudes from the yoke portion toward the hollow interior of the core. Here, when configuring the motor, it is assumed that the position of the tooth portion is periodically shifted in the stacking direction of the stacked cores, and thereby the tooth portion is inclined (skewed) with respect to the stacking direction. Patent Document 1 proposes a configuration for reducing cogging torque in a brushless motor and preventing an increase in size of the motor.

JP 2006-33989 A

  In order to reduce the vibration and operating noise of the motor, it is necessary to consider not only the cogging torque but also the torque ripple. That is, there is a demand for a configuration that can reduce torque ripple as compared with the prior art.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a stator for a rotating electrical machine that can reduce torque ripple and reduce vibration and operating noise. .

In order to achieve the above object, the present invention has a laminated core formed by laminating a plurality of core members each having a yoke portion and a teeth portion protruding from the yoke portion, and a plurality of core members. The laminated core is a stator for a rotating electrical machine that is connected in an annular shape so that the teeth portion is directed inward,
A slit is formed between the teeth portions of the adjacent laminated cores, and the core member is skewed in one laminated core,
The skew phase difference of the core member is maximum at a torque maximum current advance position where the rotating electrical machine has a maximum torque, and decreases as the distance from the torque maximum current advance position increases.

  That is, in the present invention, a skew phase difference is provided between the core members skewed in the laminated core. Specifically, the skew phase difference is set to the maximum at the position of the maximum torque current advance angle (best advance angle) at which the rotating electrical machine has the maximum torque, and is reduced as the distance from the best advance angle increases.

  At the best advance angle position and in the vicinity thereof, although the generated torque per core member increases, the number of core members contributing to the generation of torque is small. On the other hand, in the place away from the best advance angle position, although the generated torque per core member is small, the number of core members contributing to the generation of torque is large. Therefore, the generated torque is averaged. As a result, torque ripple is reduced.

  In a rotating electric machine with reduced torque ripple, vibration and operation noise are reduced. That is, by adopting the above-described configuration, it is possible to reduce vibrations and operating sounds of the rotating electrical machine.

  In many cases, the slit formed by the teeth portions of adjacent laminated cores bends (curves or bends) with the provision of the skew phase difference as described above.

  The change in the skew phase difference between the core members is preferably gradual. In other words, the skew phase difference may be gradually reduced as the distance from the best advance (torque maximum current advance) position increases. In this case, the change in the generated torque along the lamination direction of the laminated core also becomes gradual. That is, the change in torque becomes gentle. For this reason, torque ripple can be further reduced, so that further reduction of vibration and operating noise of the rotating electrical machine can be achieved.

  According to the present invention, the position of the best advance angle (torque maximum current advance angle) at which the rotating electrical machine has the maximum torque is maximized between the core members constituting the laminated core, and decreases as the position moves away from the best advance angle. In addition, a skew phase difference is provided. For this reason, since the generated torque along the stacking direction of the stacked cores is averaged, a rotating electrical machine stator with reduced torque ripple is configured. Therefore, it is possible to effectively reduce the vibration and operation sound of the rotating electrical machine.

It is a principal part schematic plan view of the motor (rotary electric machine) comprised including the stator for rotary electric machines which concerns on embodiment of this invention. It is a principal part schematic perspective view of the said stator for rotary electric machines. It is a graph which shows the relationship between an electric current advance angle, the magnet torque of a motor, reluctance torque, and total torque. FIG. 3 is an enlarged front view of a main part of an inner peripheral surface of a stator for a rotating electrical machine shown in FIG. 5A to 5D are torque waveforms at points A to D in FIG. 4, and FIG. 5E is a waveform of the total torque of the motor. It is a principal part enlarged front view of the internal peripheral surface of the stator for rotary electric machines which concerns on a prior art. 7A to 7D are torque waveforms at points A ′ to D ′ in FIG. 6, and FIG. 7E is a waveform of the total torque of the motor. It is a principal part enlarged front view of the internal peripheral surface of the stator for rotary electric machines which concerns on another embodiment.

  Preferred embodiments of a stator for a rotating electrical machine according to the present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, the stator for a rotating electrical machine is also simply referred to as “stator”.

  FIG. 1 is a schematic plan view of a main part of a motor 12 (rotating electric machine) configured to include a stator 10 according to the present embodiment. The stator 10 has an annular shape having a hollow interior. The motor 12 is configured by inserting the rotor 14 into the hollow interior. The stator 10 and the rotor 14 are accommodated in a casing (not shown).

  The rotor 14 is configured by holding a plurality of permanent magnets 18 (for example, 12 pieces) on a rotary holder 16. An insertion hole 20 is formed in the rotation holder 16, and a rotation shaft (not shown) is fitted into the insertion hole 20. Therefore, the rotor 14 and the rotating shaft rotate integrally.

  The stator 10 has a laminated core 24 in which a plurality of divided cores 22 (core members) are laminated. The divided core 22 will be briefly described. The divided core 22 is manufactured by punching a magnetic steel sheet into a substantially T shape, and has a yoke portion 26 having a predetermined arc shape, and a hollow portion formed from the yoke portion 26. And a teeth portion 28 protruding toward the inside. The curved arcuate outer peripheral surface of the yoke portion 26 becomes the outer peripheral wall of the stator 10.

  The teeth portion 28 becomes narrower in a taper shape from the proximal end portion connected to the yoke portion 26 toward the distal end portion on the hollow inner side. A widened portion 30 extending substantially parallel to the yoke portion 26 is provided at the distal end portion. Since the widened portion 30 exists, the tip of the yoke portion 26 is wider than the base end portion.

  An electromagnetic coil 32 is wound around the tooth portion 28 except for the widened portion 30. The width of the wound electromagnetic coil 32 is smaller than that of the widened portion 30. For this reason, the electromagnetic coil 32 is prevented from detaching to the hollow inner side. That is, the widened portion 30 prevents the electromagnetic coil 32 from coming off. Although not shown in particular, the laminated core 24 is covered with an insulator. The electromagnetic coil 32 is wound on this insulator.

  In adjacent laminated cores 24, end surfaces in the extending direction of the yoke portions 26 are in contact with or connected to each other. Thereby, a plurality of laminated cores 24 (for example, 12 pieces) are connected in an annular shape. On the other hand, the widened portions 30 and 30 are separated from each other. Therefore, on the inner peripheral side of the stator 10, as shown in FIG. 2, a slit 34 is opened between the widened portions 30 and 30.

  In the stator 10 according to the related art, when the divided core 22 is not skewed, the slit is a straight line extending along the height direction of the stator 10. Further, when the divided core 22 is skewed, a linear slit 50 inclined with respect to the height direction of the stator 10 is formed (see FIG. 6). That is, in both the former and the latter, the slit has a linear shape.

  On the other hand, in the present embodiment, in one laminated core 24, the divided cores 22 are laminated so that a skew phase difference is generated in the tooth portion 28. Therefore, the slit 34 has a curved shape (see FIG. 2). Specifically, the skew phase difference is maximum at the maximum torque current advance angle position (hereinafter referred to as “best advance angle position”) and decreases as the distance from the best advance angle position increases.

  Here, the best advance angle is defined as the current advance angle at which the total torque of the motor 12 is maximum. The total torque of the motor 12 is the sum of the magnet torque and the reluctance torque, but the value varies depending on the phase difference of the alternating magnetic field generated by the rotor 14 and the electromagnetic coil 32. Since the phase of the alternating magnetic field depends on the current advance angle, for example, the correlation shown in FIG. 3 is obtained between the current advance angle and the total torque.

  2 and 3 exemplify a case where the current advance angle (best advance angle) at which the total torque is maximum is 36 ° and the best advance angle position is the center in the stacking direction. Therefore, in this case, as exaggeratedly shown in FIG. 4, the skew phase difference is set to the maximum at the center in the stacking direction and becomes smaller toward the ends in the stacking direction (that is, the lower end and the upper end). The current advance angle at the lower end is 48 °, and the current advance angle at the upper end is 24 °.

  In the present embodiment, the skew phase difference is set to gradually change from the best advance angle position toward the lower end or the upper end. That is, the skew phase difference is different for each stacked position of the divided cores 22. For this reason, as shown in FIG. 2, the slit 34 is curved (bent). In the example of FIG. 2, the slit 34 has a cubic function parabolic shape. The opening width of the slit 34 may be constant, or a part thereof may be large and another part may be small.

  The motor 12 including the stator 10 according to the present embodiment is basically configured as described above. Next, the function and effect will be described.

  When the motor 12 is operated, the electromagnetic coil 32 is energized. As a result, an alternating magnetic field is generated in the stator 10. Since this alternating magnetic field and the permanent magnet 18 of the rotor 14 are repeatedly attracted and repelled, the rotor 14 and the rotary shaft rotate integrally. That is, an output can be taken out via the rotating shaft.

  Here, in the present embodiment, as shown in FIG. 4, the laminated core 24 is skewed by providing a skew phase difference in the difference in the laminated position of the divided cores 22 (the distance from the best advance angle position). . For this reason, torque ripple is reduced. The reason is presumed as follows.

  When the split cores 22 are stacked as in the present embodiment, the generated torque per one split core 22 is large at the best advance angle position and in the vicinity thereof, but the skew phase difference is large as described above. For this reason, the number of the split cores 22 contributing to the generation of torque is small. On the contrary, in the position away from the best advance angle position, the generated torque per one of the divided cores 22 is small, but since the skew phase difference is small, the number of divided cores 22 contributing to the generation of torque is large. Become.

  Therefore, when the generated torques at points A, B, C, and D in FIG. 4 are compared, the waveforms have substantially the same shape as shown in FIGS. 5A to 5D, and the maximum current advance angle is large. Is different. For this reason, as shown in FIG. 5E, the total torque becomes substantially flat. This is because the torque at each point is canceled and averaged. This means that torque ripple is reduced.

  In the motor 12 with reduced torque ripple, vibration and operating noise are reduced. That is, by adopting the above configuration, it is possible to reduce the vibration and operating noise of the motor 12.

  In addition, in the present embodiment, the skew phase difference is gradually changed, so that the generated torque gradually changes from the lower end to the upper end of the slit 34. That is, it is possible to avoid a sudden change in the generated torque. For this reason, the total torque tends to be further flat. Therefore, vibration and operating noise of the motor 12 can be effectively reduced.

  FIG. 6 is an enlarged front view of the main part of the inner peripheral surface of the stator 54 formed by the split cores 52 skewed in the prior art. Assuming that the best advance angle is 36 ° as in FIGS. 3 and 4 and the best advance angle position is the center of the laminated core 56 in the stacking direction, the current advance increases toward the lower end and the upper end in the stacking direction. The angle is retarded and advanced.

  In the prior art, the skew phase difference is constant. For this reason, the slit 50 is a straight line inclined with respect to the height direction of the stator 54.

  In this case, the generated torque per piece of the split core 52 is large at the best advance angle position and the vicinity thereof, and decreases as the distance from the best advance angle position increases. On the other hand, the number of split cores 52 that contribute to the generation of torque is the same. This is because the skew phase difference is constant in the stacking direction regardless of whether it is close to or away from the best advance angle position.

  Therefore, in this case, when the generated torques at the respective lamination positions at points A ′, B ′, C ′, and D ′ in FIG. 6 corresponding to the lamination positions A to D are compared, FIG. As shown to 7D, it becomes a waveform from which the maximum height and spread of a peak differ. For this reason, the total torque also has a waveform in which peaks and valleys appear as shown in FIG. 7E. That is, torque ripple is recognized.

  From this, it is understood that the difference in generated torque caused by the difference in current advance angle can be controlled by manufacturing the laminated core 24 while making the skew phase difference different.

  Note that the best advance angle position is not always at the center in the stacking direction, and may be another position such as point B, for example. Also in this case, the skew phase difference at the best advance angle position is maximized. That is, in this example, the skew phase difference is maximized at the point B, and the skew phase difference is reduced as the distance from the point B increases.

  The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, the skew phase difference of the divided cores 22 of several layers (for example, about 2 to 5 layers) in one laminated core 24 may be set to zero.

  Moreover, you may make it comprise the stator 62 in which the slit 60 of the quadratic function parabolic shape shown in FIG. 8 was formed. In this case, when the best advance angle position is the center in the stacking direction of the laminated core 64 (divided core 66), the sum of the opening widths at the points X and Y is set larger than the sum of the opening widths at other portions. do it.

  Further, the core member is not limited to the substantially T-shaped divided cores 22 and 66, and a yoke portion having an annular shape, and a teeth portion projecting inward in the diameter direction of the yoke portion. It may have. That is, in this case, the core member is formed of a torus, and the laminated core is configured by stacking the yoke portions. At this time, the tooth portion is skewed in the same manner as described above.

  Even in this configuration, it is needless to say that the same effect as the above-described embodiment can be obtained.

  The rotating electrical machine may be a generator. In this case, if the rotating shaft is rotated (input is given to the rotating shaft), the rotor 14 follows and rotates. As a result, an alternating current is generated in the electromagnetic coil 32.

DESCRIPTION OF SYMBOLS 10, 54, 62 ... Stator for rotary electric machines 12 ... Motor 14 ... Rotor 18 ... Permanent magnets 22, 52, 66 ... Split cores 24, 56, 64 ... Laminated core 26 ... Yoke part 28 ... Teeth part 32 ... Electromagnetic coil 34, 50, 60 ... slit

Claims (2)

It has a laminated core formed by laminating a plurality of core members each having a yoke part and a teeth part protruding from the yoke part, and the plurality of laminated cores are oriented with the teeth part inward. A stator for a rotating electrical machine connected in an annular shape,
A slit is formed between the teeth portions of the adjacent laminated cores, and the core member is skewed in one laminated core,
The skew phase difference of the core member is maximum at a torque maximum current advance position at which the rotary electric machine has a maximum torque, and decreases as the distance from the torque maximum current advance position is increased. .   2. The stator for a rotating electrical machine according to claim 1, wherein the skew phase difference gradually decreases with increasing distance from the torque maximum current advance position.

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