JP6654478B2 - Rotating electric machine rotor - Google Patents

Description

  The present invention relates to a rotor for a rotating electric machine including a rotor core and one or more magnetic pole pairs.

  Conventionally, three-phase rotating electric machines have been widely known. Such a three-phase rotating electric machine has a stator and a rotor, and the rotor has a rotating shaft mounted at its center. The rotating shaft is rotatably attached to the housing via a bearing, and rotates together with the rotor with energization of the stator coil. The stator has a stator core and a stator coil wound around the stator core. The stator coil has three-phase coils, that is, a U-phase coil, a V-phase coil, and a W-phase coil. By applying a three-phase alternating current to the three-phase coil, a rotating magnetic field is generated, and the rotor rotates.

JP 2014-11827 A

  By the way, in the conventional rotary electric machine, there is a problem that the electrolytic corrosion of the bearing that supports the rotating shaft occurs. This will be described with reference to FIG. FIG. 17 is a diagram illustrating a configuration of a conventional rotating electric machine 10. In the rotating electric machine 10, when a magnetic unbalance occurs inside the rotating electric machine 10, a magnetic flux of a higher electric cycle (hereinafter referred to as “unbalanced magnetic flux 50”) is generated around the rotating shaft 16. Then, due to the unbalanced magnetic flux 50, a voltage (hereinafter referred to as “axial voltage”) is induced at both ends of the rotating shaft 16. FIG. 18 is a graph showing an example of the waveform of the shaft voltage VS and the current flowing through the U-phase coil (U-phase current AU). As shown in FIG. 18, the shaft voltage VS is a third harmonic voltage having a frequency three times the fundamental wave. The shaft voltage VS is applied to the inner and outer rings of the rotating bearing 19 via the rotating shaft 16 and the housing 18. The inner and outer rings of the bearing 19 are insulated by a lubricating oil film. However, since the lubricating oil film is as thin as several μm, dielectric breakdown occurs when a certain voltage or more (about several V) is applied. When the insulation of the inner and outer rings of the bearing 19 is broken, an induced current 52 flows in a circulation path of “the rotating shaft 16, the bearing 19, the housing 18, and the rotating shaft 16” as shown by a broken line in FIG. 17. At this time, since the Joule loss concentrates on the dielectric breakdown portion, that is, the bearing 19, there is a problem that the electrolytic corrosion of the bearing 19 proceeds.

  Patent Literature 1 discloses a technique for separately providing a conductor member that mechanically connects a rotating shaft and a housing in order to suppress such electrolytic corrosion of a bearing. With such a configuration, the induced current flows predominantly through the conductor member having lower impedance than the bearing, so that electrolytic corrosion of the bearing can be suppressed.

  However, in the technique of Patent Literature 1, it is necessary to separately provide a conductor member, and there are structural restrictions on a rotating shaft, a housing, and a rotating output portion. Another problem is that the cost increases.

  In view of the above, an object of the present invention is to provide a rotor of a rotating electric machine that can suppress electric corrosion of a bearing without providing a conductor member that connects a rotating shaft and a housing.

The rotor of the rotating electrical machine of the present invention is a rotor core, a pair of at least one rotor magnetic pole provided in the rotor core, and wound around the rotor core so as to extend in a rotor radial direction at a position outside the rotor axial direction of the rotor core, And at least one N-pole element coil wound around an N-pole rotor magnetic pole and at least one N-pole element coil wound around an N-pole rotor magnetic pole. And one or more S-pole element coils, wherein each closed circuit is configured by connecting one or more N-pole element coils and one or more S-pole element coils in series. I do.

  With this configuration, a tertiary induced voltage is induced in the cancel coil due to the unbalanced magnetic flux flowing in the circumferential direction. Then, the induced voltage causes an induced current to flow through the cancel coil, and the induced current generates a magnetic flux that cancels the unbalanced magnetic flux. As a result, the unbalanced magnetic flux is reduced, and the electrolytic corrosion of the bearing is suppressed.

  In each element coil, not only a third-order induced voltage but also a sixth-order induced voltage is induced. With the above configuration, the sixth-order induced voltage induced in the N-pole element coil and the sixth-order induced voltage induced in the S-pole element coil cancel each other. As a result, the sixth-order induced current does not flow in the closed circuit, and only a relatively small third-order induced current flows. As a result, heat generation from the cancel coil and an increase in the size of the cancel coil can be prevented.

  In this case, the one or more N-pole element coils included in the one closed circuit and the one or more S-pole element coils included in the one closed circuit are a pair of magnetic poles centered on the rotation center of the rotor. Between them, it is desirable to be electrically rotationally symmetric.

  With such a configuration, the magnetic effect of the N-pole element coil and the S-pole element coil included in one closed circuit can be made the same, and the sixth-order induced current can be more reliably prevented.

According to another aspect of the present invention, there is provided a rotor of a rotating electrical machine, wherein the rotor core is wound around the rotor core so as to extend in a rotor radial direction at a position outside the rotor axial direction of the rotor core. And a cancel coil that is turned to form one or more closed circuits, wherein the cancel coil has the N-pole rotor magnetic pole so as to radially cross the N-pole rotor magnetic pole at a position outside the rotor axial direction of the rotor core. And one or more N-pole element coils wound around the rotor core , and wound around the S-pole rotor magnetic pole so as to radially cross the S-pole rotor pole at a position outside the rotor axial direction of the rotor core. Only one of the one or more south pole element coils.

  With such a configuration, the direction of the flow of the cancel magnetic flux caused by the sixth-order induced current induced in the plurality of element coils becomes the same, so that the magnetic resistance of the magnetic path of the cancel magnetic flux decreases. As a result, the sixth-order induced current induced in the element coil is reduced, and heat generation from the cancel coil and an increase in the size of the cancel coil can be prevented.

  In another preferred aspect, the cancel coil includes a plurality of element coils wound around one rotor magnetic pole, and the plurality of cancel coils wound around the one rotor magnetic pole include the rotor coil. Are electrically axisymmetric with respect to an imaginary line connecting the center of rotation of the rotor pole and the circumferential center of the one rotor magnetic pole.

  By adopting such a configuration, electromagnetic balance can be obtained, so that unbalanced magnetic flux can be reduced more stably.

  According to the present invention, a tertiary induced voltage is induced in the cancel coil due to the unbalanced magnetic flux flowing in the circumferential direction. Then, the induced voltage causes an induced current to flow through the cancel coil, and the induced current generates a magnetic flux that cancels the unbalanced magnetic flux. As a result, the unbalanced magnetic flux is reduced, and the electrolytic corrosion of the bearing is suppressed.

1 is a cross-sectional view of a rotating electric machine according to an embodiment of the present invention. It is AA sectional drawing of FIG. It is a wiring diagram of a cancellation coil. It is a connection diagram of the cancellation coil of a comparative example. It is a graph which shows a tertiary induced voltage. It is a graph which shows a shaft voltage. It is a graph which shows the sixth induced voltage. It is a graph which shows an induced current. It is a cross section of a rotor in a second embodiment. FIG. 10 is a connection diagram of a cancel coil provided in the rotor of FIG. 9. It is a figure showing an example of another rotor. It is a figure showing an example of another rotor. It is a figure which shows an example of the winding system of an element coil. It is a figure which shows another example of the winding system of an element coil. It is a figure showing an example of another rotor. It is a figure showing an example of another rotor. It is a longitudinal section of the conventional rotary electric machine. 9 is a graph showing a U-phase current and a shaft voltage in a conventional rotating electric machine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a rotating electric machine 10 according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA of FIG. In the following drawings, the cancel coil 32 is shown relatively large for easy viewing, but the cancel coil 32 is actually smaller. In the following description, “axial direction”, “circumferential direction”, and “radial direction” mean the axial direction, circumferential direction, and radial direction of the rotor 12.

  The rotating electric machine 10 is roughly divided into a rotor 12, a stator 14, a rotating shaft 16, and a housing 18. The rotor 12 includes a rotor core 20, one or more magnetic pole pairs 23 provided in the rotor core 20, and a cancel coil 32. The rotor core 20 is a cylindrical member formed by laminating a plurality of electromagnetic steel plates (for example, silicon steel plates) in the axial direction. The magnetic pole pair 23 includes an N-pole rotor magnetic pole 22n and an S-pole rotor magnetic pole 22s. The rotor magnetic poles 22n and 22s are configured by permanent magnets embedded in the rotor core 20. In the present embodiment, the magnetic pole whose radially outer surface is formed of an N-pole permanent magnet is an N-pole rotor magnetic pole 22n, and the magnetic pole whose radially outer surface is formed of an S-pole permanent magnet is an S-pole rotor magnetic pole 22s. Call. The N-pole rotor magnetic poles 22n and the S-pole rotor magnetic poles 22s are alternately arranged in the circumferential direction. Although the rotor 12 of the present embodiment has four magnetic pole pairs 23, the number may be changed as appropriate. The cancel coil 32 is a coil wound around the rotor core 20, which will be described later in detail.

  The rotation shaft 16 is inserted through and fixed to the center of the rotor core 20. Both ends of the rotating shaft 16 are attached to a housing 18 via bearings 19, and the rotating shaft 16 and the rotor core 20 fixed to the rotating shaft 16 are rotatable with respect to the housing 18.

  The bearing 19 is configured by arranging a plurality of rolling elements 19b (spheres) between the outer ring 19a and the inner ring 19c, and between the outer ring 19a and the rolling elements 19b and between the inner ring 19c and the rolling elements 19b. Has a lubricating oil film interposed. This lubricating oil film functions not only as a lubricant for smoothing the movement of the rolling elements 19b, but also as an insulating member for insulating the outer ring 19a and the inner ring 19c. With the lubricating oil film interposed, the rotating shaft 16 and the housing 18 are electrically insulated.

  The stator 14 has a stator core 24 and a stator coil 30. The stator core 24 is a substantially cylindrical member arranged concentrically with the rotor 12 and has a plurality of teeth 28 projecting radially inward. A slot, which is a space into which the stator coil 30 is inserted, is formed between two adjacent teeth 28. Stator coil 30 includes a U-phase coil, a V-phase coil, and a W-phase coil, and these coils are wound around teeth 28. Then, by applying a three-phase alternating current to the stator coil 30, a rotating magnetic field is formed, and the rotor 12 rotates.

  Next, the cancel coil 32 will be described. As described above, the cancel coil 32 is a coil wound around the rotor core 20. The cancel coil 32 includes an N-pole element coil 34n wound mainly around the N-pole rotor magnetic pole 22n, and an S-pole element coil 34s wound mainly around the S-pole rotor magnetic pole 22s. It is roughly divided. In the following, when it is not necessary to distinguish between the north pole and the south pole, the suffixes n and s are omitted and simply referred to as “element coil 34”.

  In the present embodiment, three N-pole element coils 34n are wound around one N-pole rotor magnetic pole 22n, and twelve N-pole element coils 34n are provided for the entire rotor 12. Similarly, three S-pole element coils 34s are wound around one S-pole rotor magnetic pole 22s, and twelve S-pole element coils 34s are provided in the entire rotor 12. That is, 24 element coils 34 are provided in the entire rotor 12. Further, the pair of magnetic poles includes three corresponding N-pole element coils 34n and three S-pole element coils 34s, for a total of six.

  Each element coil 34 is wound around the rotor core 20 so as to extend in the axial direction at a position outside and inside the rotor core 20 in the radial direction, and to extend in the radial direction at a position outside the rotor core 20 in the axial direction. As will be described in detail later, three types of magnetic flux flow in the rotor core 20 in the circumferential direction. The element coil 34 is wound so as to surround the magnetic flux flowing in the circumferential direction.

  These N-pole and S-pole element coils 34n and 34s are connected so as to form one or more closed circuits. Although various connection forms are conceivable, in the present embodiment, as shown in FIG. 3, six element coils 34n and 34s corresponding to the same magnetic pole pair are connected in series with each other to form a closed circuit. Therefore, one closed circuit includes the same number (three each) of the N-pole and S-pole element coils 34n and 34s. The rotor 12 as a whole has the same number as the magnetic pole pairs 23, that is, four closed circuits.

  Next, the reason for providing the cancel coil 32 will be described. FIG. 17 is a diagram illustrating a configuration of a conventional rotating electric machine 10. In the rotating electric machine 10, when a magnetic unbalance occurs inside the rotating electric machine 10, a magnetic flux of a higher electric cycle (hereinafter referred to as “unbalanced magnetic flux 50”) is generated around the rotating shaft 16. Then, due to the unbalanced magnetic flux 50, a voltage (hereinafter, referred to as “axial voltage”) is induced across the rotating shaft 16. This shaft voltage is applied to the inner and outer rings 19 a and 19 c of the rotating bearing 19 via the rotating shaft 16 and the housing 18. The inner and outer rings 19a and 19c of the bearing 19 are insulated by a lubricating oil film. However, since the lubricating oil film is as thin as several μm, the dielectric breakdown occurs when a certain voltage or more (approximately several V) is applied. When the insulation between the outer ring 19a and the inner ring 19c of the bearing 19 is broken, as shown in FIG. 17, an induced current 52 flows in a circulation path of "the rotating shaft 16, the bearing 19, the housing 18, and the rotating shaft 16." At this time, since the Joule loss concentrates on the dielectric breakdown portion, that is, the bearing 19, there is a problem that the electrolytic corrosion of the bearing 19 proceeds.

  In order to solve such a problem, it has been proposed in some cases to separately provide a conductor member for connecting the rotating shaft 16 and the housing 18. With such a configuration, the induced current 52 flows predominantly through the conductor member having a smaller impedance than the bearing 19, so that the electrolytic corrosion of the bearing 19 can be suppressed. However, the adoption of such a conductor member causes a structural restriction, which leads to another problem that the degree of freedom in design is reduced and the size, weight, and cost of the entire rotating electric machine 10 are increased.

  In the present embodiment, the cancel coil 32 is provided in order to suppress the electrolytic corrosion of the bearing 19 without providing a conductor member for connecting the rotating shaft 16 and the housing 18. As described above, the cancel coil 32 is wound around the rotor core 20, and three types of magnetic flux flow through the rotor core 20 roughly.

  One is an unbalanced magnetic flux 50 generated by the magnetic imbalance of the rotating electric machine 10. The unbalanced magnetic flux 50 travels in the rotor core 20 in the circumferential direction. The unbalanced magnetic flux 50 is a tertiary magnetic flux that changes at a frequency three times the fundamental frequency.

  The other is a magnetic flux generated by a permanent magnet embedded in the rotor core 20. This magnetic flux is a magnetic flux of a DC component in which the direction of the magnetic flux does not change. Hereinafter, this magnetic flux is referred to as “DC magnetic flux”. This DC magnetic flux is a magnetic flux necessary for generating the output torque of the rotating electric machine 10.

  Further, a sixth-order magnetic flux is also generated in the rotor core 20 due to magnetic imbalance. Hereinafter, this magnetic flux is referred to as “sixth-order magnetic flux”. Like the unbalanced magnetic flux, the sixth-order magnetic flux flows through the rotor core 20 in the circumferential direction, and changes at a frequency six times the fundamental frequency.

  The element coil 34 constituting the cancel coil 32 is wound around the rotor core 20 so as to surround the unbalanced magnetic flux 50, the DC magnetic flux, and the sixth-order magnetic flux flowing in the rotor core 20 in the circumferential direction. In other words, the unbalanced magnetic flux 50, the DC magnetic flux, and the sixth-order magnetic flux pass through the inside of the cancel coil 32. However, since the DC magnetic flux does not change with time, no voltage is induced in the cancel coil 32 due to the DC magnetic flux. On the other hand, since the unbalanced magnetic flux 50 and the sixth-order magnetic flux change over time, a voltage is induced in the cancel coil 32 according to the time-dependent change of the unbalanced magnetic flux 50 and the sixth-order magnetic flux.

  Hereinafter, the voltage induced according to the time change of the unbalanced magnetic flux 50 is referred to as “third induced voltage”, and the voltage induced according to the time change of the sixth magnetic flux is referred to as “sixth induced voltage”. FIG. 5 is a graph showing a tertiary induced voltage. The tertiary induced voltage N_V3 induced in the N-pole element coil 34n and the tertiary induced voltage S_V3 induced in the S-pole element coil 34s change at the same phase and frequency. Therefore, when the N-pole element coil 34n and the S-pole element coil 34s are connected in series to form a closed circuit, the tertiary induced voltages N_V3 and S_V3 induced in the respective element coils 34 are summed without canceling each other, The tertiary voltage A_V3 of the entire closed circuit has a high value. Then, when a high voltage is induced in the entire closed circuit, an induced current flows through these closed circuits. This induced current flows in such a direction as to cancel the unbalanced magnetic flux 50.

  FIG. 6 is a graph showing a difference in axis voltage depending on the presence or absence of the cancel coil 32. 6, the solid line indicates the shaft voltage Va when the cancel coil 32 is provided, and the broken line indicates the shaft voltage Vb when the cancel coil 32 is not provided. As is clear from FIG. 6, by providing the cancel coil 32, the unbalanced magnetic flux 50 is reduced by the tertiary induced current flowing through the cancel coil 32, so that the shaft voltage is also reduced. When the shaft voltage is reduced, dielectric breakdown of the lubricating oil film of the bearing 19 is prevented, and electric corrosion of the bearing 19 is effectively prevented.

  Next, a sixth-order induced voltage will be described. FIG. 7 is a graph showing a sixth-order induced voltage. In FIG. 7, a solid line indicates a sixth-order induced voltage N_V6 induced in the N-pole element coil 34n, and a broken line indicates a sixth-order induced voltage S_V6 induced in the S-pole element coil 34s. As is clear from FIG. 7, the N-pole sixth-order induced voltage N_V6 and the S-pole sixth-order induced voltage S_V6 have phases opposite to each other. In the present embodiment, the N-pole element coil 34n and the S-pole element coil 34s are connected in series with each other to cancel out the sixth-order induced voltages N_V6 and S_V6 of the N-pole and S-pole. The reason for this configuration will be described with reference to a comparative example of FIG.

  In the present embodiment, as shown in FIG. 3, the same number of N-pole element coils 34n and S-pole element coils 34s are provided in one closed circuit. However, as shown in the comparative example of FIG. 4, it is not impossible to consider providing a closed circuit having only the N-pole element coil 34n and a closed circuit having only the S-pole element coil 34s. However, when the connection is made as in the comparative example of FIG. 4, the value of the current flowing through each element coil 34 is significantly increased, causing a problem such as heat generation, and it is necessary to take measures such as increasing the diameter of the element coil 34. . This is because the magnetic resistance of the magnetic flux generated by the induced current increases. That is, when a sixth-order induced voltage is induced in the element coil 34 and an induced current flows, a magnetic flux that cancels the sixth-order magnetic flux and a cancel magnetic flux are generated. The direction of the cancel magnetic flux is opposite between the S pole and the N pole. Therefore, the cancel magnetic flux generated by the induced current flowing through the N-pole element coil 34n functions as a magnetic resistance that obstructs the flow of the cancel magnetic flux generated by the induced current flowing through the S-pole element coil 34s. Similarly, the cancel magnetic flux generated by the induced current flowing through the S-pole element coil 34s functions as a magnetic resistance that obstructs the flow of the cancel magnetic flux generated by the induced current flowing through the N-pole element coil 34n. As described above, the greater the magnetic resistance that hinders the flow of the cancel magnetic flux, the greater the value of the induced current. As a result, as shown in the comparative example of FIG. 4, when the N-pole element coil 34n and the S-pole element coil 34s are formed as independent closed circuits, the value of the sixth-order induced current flowing through each closed circuit is very large. Become.

  On the other hand, in the present embodiment, as shown in FIG. 3, the same number of N-pole element coils 34n and S-pole element coils 34s are connected in series. In this case, since the sixth-order induced voltages induced in the N-pole and S-pole element coils 34n and 34s cancel each other, the sixth-order voltage value A_V6 of the entire closed circuit becomes substantially zero. As a result, no sixth-order induced current flows through each element coil.

  FIG. 8 is a graph showing an induced current flowing through the element coil 34. 8, the broken line indicates the induced current flowing through each element coil 34 in the case of the present embodiment (connection in FIG. 3), and the solid line indicates the connection in FIG. As is clear from FIG. 8, when the N-pole element coil 34n and the S-pole element coil 34s are provided as independent circuits, the waveform of the induced current becomes very large sixth-order induced current and relatively small third-order induced current. The waveform becomes a sum of the current and the current. On the other hand, when the N-pole element coil 34n and the S-pole element coil 34s are connected to each other in series as in the present embodiment, a sixth-order induced current does not flow. Only the tertiary induced current flows. That is, when the N-pole element coil 34n and the S-pole element coil 34s are connected in series as in the present embodiment, the current flowing through the element coil 34 can be reduced, and the problem such as heat generation is greatly reduced. Can be prevented. Also, if the flowing current is small, the diameter and weight of the element coil 34 can be reduced, and the weight and cost of the rotating electric machine 10 as a whole can be reduced.

  As is clear from the above description, according to the present embodiment, since the cancel coil 32 wound around the rotor core 20 is provided, the unbalanced magnetic flux 50 can be canceled, and the electric corrosion of the bearing 19 can be effectively reduced. Can be prevented. Further, since the N-pole element coil 34n and the S-pole element coil 34s are connected in series with each other, the sixth-order induced current can be reduced to almost zero, and the current value flowing through each cancel coil 32 can be reduced. Can be.

  Next, a second embodiment will be described with reference to FIGS. FIG. 9 is a schematic cross-sectional view of the rotor 12 in the second embodiment, and FIG. 10 is a connection diagram of the cancel coil 32 in the second embodiment. As is clear from FIG. 9, in the present embodiment, only the N-pole element coil 34n wound around the N-pole rotor magnetic pole 22n is provided, and the S-pole wound around the S-pole rotor magnetic pole 22s is provided. The pole element coil 34s is not provided. Then, as shown in FIG. 10, three N-pole element coils 34n corresponding to one N-pole rotor magnetic pole 22n are connected in series with each other to form a closed circuit. The rotor 12 as a whole has four closed circuits having only the N-pole element coils 34n.

  In such a configuration, a tertiary induced voltage N_V3 caused by the unbalanced magnetic flux 50 and a sixth-order induced voltage N_V6 caused by the sixth-order magnetic flux are induced in each N-pole element coil 34n. When the tertiary induced voltage N_V3 is induced, a tertiary induced current is induced in the N-pole element coil 34n in a direction to cancel the unbalanced magnetic flux 50. As a result, the unbalanced magnetic flux 50 is reduced, and the electrolytic corrosion of the bearing 19 is prevented.

  A sixth-order induced current flows in the N-pole element coil 34n in a direction to cancel the sixth-order magnetic flux. Cancellation magnetic flux is generated by the sixth induced current. As described above, as shown in the comparative example of FIG. 4, in the case where the S-pole element coil 34s independent of the N-pole element coil 34n is further provided, the cancellation of the S-pole that hinders the cancellation magnetic flux of the N-pole is performed. Since a magnetic flux is generated, a large sixth-order current flows through the N-pole element coil 34n. However, in the present embodiment, since the S-pole element coil 34s is not provided, the magnetic resistance of the magnetic path of the N-pole cancel magnetic flux is small. As a result, the sixth-order induced current flowing through the N-pole element coil 34n becomes very small. Thus, problems such as heat generation from the cancel coil 32 and an increase in diameter and weight of the cancel coil 32 can be prevented.

  As is apparent from the above description, even in a configuration in which only the N-pole element coil 34n is provided and the S-pole element coil 34s is not provided as in the second embodiment, the electric corrosion of the bearing 19 is effectively prevented while the cancellation is performed. The current flowing through the coil 32 can be reduced.

  Next, variations of the configuration of the cancel coil 32 will be described. As described above, the cancel coil 32 includes one or more element coils 34. If only the purpose of reducing the unbalanced magnetic flux 50 (suppressing the electrolytic corrosion of the bearing 19) is to use the element coil 34, as shown in FIG. 4, both the N-pole element coil 34n and the S-pole element coil 34s are used. They may be provided so as to form independent closed circuits.

  On the other hand, when it is desired to reduce the sixth-order induced current, the N-pole and S-pole element coils 34n and 34s are connected in series as in the first embodiment, or the N-pole element coil 34n as in the second embodiment. It is preferable to provide only one of the S-pole element coil 34s. In the following, a configuration in which both the N-pole and the S-pole element coils 34n and 34s are provided in one closed circuit as shown in FIG. 3 is referred to as a "different pole mixed configuration", and as shown in FIG. A form in which only one of the N-pole element coil 34n and the S-pole element coil 34s is provided is called a "single-pole configuration".

  In the case of the heteropolar mixed configuration, the number of the N-pole element coil 34n and the number of the S-pole element coils 34s included in one closed circuit are not particularly limited, and each may be one or more. However, it is preferable that the one or more N-pole element coils 34n and the one or more S-pole element coils 34s included in one closed circuit have the same magnetomotive force. That is, it is desirable that the materials and shapes of the windings constituting the element coils 34n and 34s, the number of turns, and the like be equal.

  Further, in the case of the mixed heteropolar configuration, the N-pole element coil 34n and the S-pole element coil 34s included in one closed circuit are electrically rotationally symmetric between the magnetic poles forming a pair with the rotation center O of the rotor as a base point. It is desirable that they are arranged. Thereby, the magnetic action of the N-pole element coil 34n included in one closed circuit and the magnetic action of the S-pole element coil 34s can be made almost the same, so that the sixth-order induced current can be more reliably prevented.

  The number of element coils 34 wound around one rotor magnetic pole 22n, 22s is not particularly limited in any of the mixed heteropolar configuration and the monopolar configuration. Therefore, three element coils 34 may be wound around one rotor magnetic pole 22n, 22s as shown in FIGS. 1 and 9, or two element coils 34 may be wound as shown in FIG. You can turn it. Alternatively, a smaller or larger number of element coils 34 may be wound.

  It is preferable that the element coils 34 wound around the one rotor magnetic poles 22n and 22s be electrically symmetrical with respect to the d axis Ld. The d-axis Ld is an imaginary line connecting the rotation center O of the rotor 12 and the circumferential centers of the one rotor magnetic poles 22n and 22s. By arranging the d-axis Ld line-symmetrically, electromagnetic balance can be obtained, so that the unbalanced magnetic flux can be more stably reduced.

  In the first and second embodiments, the element coils 34 are wound around all the rotor magnetic poles 22n and 22s, in other words, the plurality of element coils 34 are uniformly distributed in the circumferential direction. The number and position of the element coils 34 may be appropriately changed. For example, as shown in FIG. 11, the element coil 34 is wound only around two adjacent magnetic pole pairs 23, and the element coil 34 is not provided around the remaining two magnetic pole pairs 23. Good. Further, as shown in FIG. 12, the element coil 34 may be provided only around the two S-pole rotor magnetic poles 22s that are separated from each other.

  The number of element coils 34 constituting each closed circuit is not particularly limited as long as it is one or more. Therefore, the number of element coils forming a closed circuit and the like may be appropriately changed. Therefore, for example, a single closed circuit may be formed by connecting all of the plurality of element coils 34 constituting the cancel coil 32 in series. With such a configuration, the magnetic imbalance caused by the eccentricity of the rotor 12 can be canceled in the closed circuit, so that the unbalanced magnetic flux can be reduced more effectively, and the sixth-order induced current can be reduced. it can. In the case of a configuration having a plurality of closed circuits as in the first and second embodiments, the structure is easily affected by magnetic imbalance, but the structure of one closed circuit can be simplified, and the winding of the cancel coil can be simplified. Becomes easier.

  Further, the winding method of each element coil 34 is not particularly limited. Therefore, as shown in FIG. 13, the element coil 34 moves in the circumferential direction after the winding end of one element coil 34 reaches the vicinity of the winding start of the one element coil 34, and the other coil adjacent to the other element coil 34 A winding method toward the coil 34 may be used. Also, as shown in FIG. 14, the element coils 34 are always arranged so that the windings advance in the circumferential direction so that the winding end of one element coil 34 starts the winding of another adjacent element coil 34. Alternatively, a spiral winding method may be used.

  Each element coil 34 is wound around the rotor core 20, and the rotor core 20 rotates at a high speed as the rotating electric machine 10 is driven. At this time, if the element coil 34 projects radially outward due to centrifugal force, there is a possibility that the element coil 34 will come into contact with the stator 14. Therefore, in order to prevent such contact between the stator 14 and the element coil 34, as shown in FIG. 15, a groove or hole or the like penetrating in the axial direction is provided in the rotor core 20 to accommodate the element coil 34. A part of the element coil 34 may be accommodated in the groove or the hole. As another form, the outer periphery of the rotor core 20 around which the element coil 34 is wound may be covered with a cover to prevent the element coil 34 from protruding radially outward. As shown in FIG. 15, a groove or a hole for accommodating a part of the element coil 34 may be provided on the inner peripheral surface of the rotor core 20.

  Further, in the first and second embodiments, the element coil 34 is configured to pass through the inside and outside of the rotor core 20 in the radial direction. However, the element coil 34 may be configured to pass through the inside of the rotor core 20. . For example, as shown in FIG. 16, some of the rotor cores 20 are formed with coolant holes 40 penetrating in the axial direction for allowing the coolant to pass therethrough at equal intervals in the circumferential direction. In the case of such a rotor core 20, a part of the element coil 34 may be accommodated in the coolant hole 40.

  In the present embodiment, each element coil 34 crosses the permanent magnet in the radial direction at both axial ends of the rotor core 20. However, the element coil 34 does not have to cross the permanent magnet as long as it surrounds at least the unbalanced magnetic flux flowing in the circumferential direction. In other words, a configuration may be adopted in which a hole penetrating in the axial direction is provided at a position radially outside the permanent magnet, and each element coil 34 passes through the hole and a position radially outside the rotor core 20.

  Furthermore, in the description so far, only the example in which the element coil 34 is wound around the rotor magnetic poles 22 n and 22 s has been described, but the element coil 34 may be wound at least on the rotor core 20 if it is wound around the rotor core 20. 22n and 22s. However, since the rotor magnetic poles 22n and 22s usually occupy most of the rotor core 20, it is difficult to wind the element coil 34 avoiding the rotor magnetic poles 22n and 22s. The reduction effect is also low.

  Further, the configuration of the rotor 12 described above is an example, and may be appropriately changed. For example, the number of magnetic pole pairs 23 may be appropriately changed as long as the number of magnetic pole pairs 23 is one or more. In the above description, one rotor magnetic pole 22n, 22s is formed of one permanent magnet having a rectangular cross section. However, the number and configuration (shape) of the permanent magnets forming the rotor magnetic poles 22n and 22s may be appropriately changed. For example, the rotor magnetic poles 22n and 22s may be constituted by permanent magnets having a substantially circular arc cross section. As another form, two permanent magnets having a substantially rectangular cross section may be arranged so as to expand in a V-shape toward the outside in the radial direction to form one rotor magnetic pole 22n, 22.

  In any case, the unbalanced magnetic flux is reduced by providing the cancel coil 32 wound around the rotor core 20 so as to advance in the radial direction at both end positions in the axial direction of the rotor core 20, thereby reducing the electrolytic corrosion of the bearing 19. Can be suppressed. In addition, a configuration in which the N-pole element coil 34n and the S-pole element coil 34s are connected in series with each other (mixed-polarity configuration), or a configuration in which only one of the N-pole and S-pole element coils 34 is provided (single pole) With this configuration, a large sixth-order induced current can be prevented from flowing, and heat generation and an increase in diameter and weight of the cancel coil 32 can be prevented.

  Reference Signs List 10 rotating electric machine, 12 rotor, 14 stator, 16 rotating shaft, 18 housing, 19 bearing, 20 rotor core, 22s rotor magnetic pole of S pole, 22n rotor magnetic pole of N pole, 23 magnetic pole pairs, 24 stator core, 28 teeth, 30 stator coil , 32 cancellation coil, 34n N-pole element coil, 34s S-pole element coil, 50 unbalanced magnetic flux, 52 induced current.

Claims (4)

A rotary electric machine rotor,
A rotor core,
A plurality of pairs of rotor magnetic poles provided in the rotor core,
A cancel coil wound around the rotor core so as to extend in the rotor radial direction at a position outside the rotor axis direction of the rotor core and forming one or more closed circuits;
Equipped with a,
The cancel coil includes one or more N-pole element coils wound around an N-pole rotor magnetic pole, and one or more S-pole element coils wound around an S-pole rotor magnetic pole;
Each closed circuit is configured by connecting one or more N-pole element coils and one or more S-pole element coils in series.
A rotor characterized in that: The rotor according to claim 1 ,
The one or more N-pole element coils included in the one closed circuit and the one or more S-pole element coils included in the one closed circuit are arranged around a rotation center of the rotor, between magnetic poles forming a pair. A rotor characterized by being electrically rotationally symmetric. A rotary electric machine rotor,
A rotor core,
A plurality of pairs of rotor magnetic poles provided in the rotor core,
A cancel coil wound around the rotor core so as to extend in the rotor radial direction at a position outside the rotor axis direction of the rotor core and forming one or more closed circuits;
With
The cancel coil includes one or more N-pole element coils wound around the N-pole rotor magnetic pole so as to radially cross the N-pole rotor magnetic pole at a position outside the rotor core in the rotor axial direction , and Including only one of one or more S-pole element coils wound around the S-pole rotor magnetic pole so as to radially cross the S-pole rotor magnetic pole at the rotor axial direction outer position of the rotor core ,
A rotor characterized in that: The rotor according to any one of claims 1 to 3 , wherein
The cancellation coil includes a plurality of element coils wound around one rotor magnetic pole,
The plurality of cancel coils wound around the one rotor magnetic pole are electrically line-symmetrically arranged with respect to an imaginary line connecting the rotation center of the rotor and the circumferential center of the one rotor magnetic pole. A rotor characterized by the above.

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