Rotating electric machine

Abstract

To improve quietness in a rotary electric machine having a specific number of magnetic poles and slots.SOLUTION: A rotary electric machine includes a rotor having multiple magnetic poles arranged in the circumferential direction, a stator core having multiple teeth in the circumferential direction, and a stator having multi-phase stator windings wound around the teeth by concentrated winding, the number of magnetic poles of the rotor is "14" and the number of slots between the teeth is "18". The stator core 31 is skewed to suppress radial vibrations of the electric 8th and 10th order components.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine.

Background Art

[0002] As a rotating electrical machine having concentrated windings, for example, a rotating electrical machine described in Patent Document 1 is known. In this Patent Document 1, a rotating electrical machine having a specific number of magnetic poles as the number of magnetic poles of the rotor and a specific number of slots as the number of slots between teeth in the stator is described. Specifically, a rotating electrical machine having 14 magnetic poles and 18 slots, a rotating electrical machine having 22 magnetic poles and 18 slots, a rotating electrical machine having 16 magnetic poles and 18 slots, and a rotating electrical machine having 20 magnetic poles and 18 slots are disclosed. And in these rotating electrical machines, by making the phase difference of the magnetomotive force in each coil body between phases fall within a predetermined phase range including 20 degrees in electrical angle, the harmonic components of the 6th or 12th electrical order are canceled out, and it has been considered that torque ripple can be suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-mentioned Patent Document 1 was filed by the applicant of the present application. According to the applicant, in a rotating electric machine with a specific number of magnetic poles and slots as described above, radial electromagnetic forces are generated in the stator in a direction that causes elliptical deformation due to the 8th and 10th order electrical components, and radial vibration occurs as a result. In this case, there is a concern that the rotating electric machine will experience problems such as noise, and its quietness will decrease. It has also been confirmed that such radial vibration occurs in rotating electric machines with a specific number of magnetic poles and slots, such as 14 poles and 18 slots, but is not a problem in a rotating electric machine with, for example, 8 poles and 12 slots.

[0005] This invention has been made in view of the above problems, and aims to improve quietness in a rotating electric machine having a specific number of magnetic poles and slots. [Means for solving the problem]

[0006] The present invention A rotor having multiple magnetic poles arranged in the circumferential direction, In a rotating electric machine comprising a stator core having multiple teeth in the circumferential direction, and a stator having multiphase stator windings wound around the teeth by concentrated winding, The rotor has (18±4) magnetic poles and 18 slots between the teeth, or The rotor has (18±2) magnetic poles and 18 slots between the teeth. The stator or rotor is characterized by being skewed in order to suppress radial vibrations of the eighth and tenth order electrical components.

[0007] In a rotating electric machine having a stator with a concentrated winding structure, if the rotor has (18±4) magnetic poles and the stator has 18 slots, or if the rotor has (18±2) magnetic poles and the stator has 18 slots, there is a concern that radial electromagnetic forces causing elliptical deformation of the stator will be generated due to the 8th and 10th order electrical components, leading to a decrease in quietness. In this regard, the above rotating electric machine is configured to have a skew applied to at least one of the stator and rotor to suppress radial vibrations of the 8th and 10th order electrical components. In this case, by adding a skew structure, the radial electromagnetic forces caused by the 8th and 10th order electrical components can be reduced, and deformation of the stator can be suppressed. As a result, quietness can be improved in a rotating electric machine having a specific number of magnetic poles and slots. [Brief explanation of the drawing]

[0008] [Figure 1] A cross-sectional view of the motor. [Figure 2] Cross-sectional view of the motor. [Figure 3] A diagram showing the electrical configuration of the control device. [Figure 4] Perspective view of the stator. [Figure 5] A perspective view showing the configuration of the stator core. [Figure 6] Winding diagram of the stator winding. [Figure 7] A diagram showing the correspondence between each section winding of the stator winding and the teeth. [Figure 8] A diagram illustrating how radial acceleration is generated by the 8th and 10th order components. [Figure 9] A perspective view showing the stepped skew structure of the stator core. [Figure 10] A diagram illustrating the skew angle of the stator core. [Figure 11] This figure shows the relationship between the radial vibration acceleration of the 8th and 10th order electrical vibrations and the skew angle. [Figure 12] A perspective view showing the linear skew structure of the stator core. [Figure 13] A perspective view showing the skew structure of the rotor. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the explanations for such parts will be based on those same reference numerals. In this embodiment, a motor 10 as a rotating electric machine will be described as an example.

[0010] The motor 10 shown in Figure 1 is a permanent magnet field type, specifically a permanent magnet field synchronous machine having three phase windings. In other words, the motor 10 is a brushless motor. It may have two sets of three phase windings. The motor 10 comprises a housing 20, a stator 30 fixed to the housing 20, a rotor 40 that rotates relative to the stator 30, and a rotating shaft 11 to which the rotor 40 is fixed. Hereinafter, in this embodiment, axial direction refers to the axial direction of the rotating shaft 11, radial direction refers to the radial direction of the rotating shaft 11, and circumferential direction refers to the circumferential direction of the rotating shaft 11.

[0011] The housing 20 is formed in a cylindrical shape, and the stator 30 and rotor 40 are housed inside the housing 20. The housing 20 is provided with bearings 23 and 24, which rotatably support the rotating shaft 11. The axis of the inner surface of the housing 20 is coaxial with the rotating shaft 11. An angle sensor 12 is provided on the tip side of the rotating shaft 11. The angle sensor 12 may be a magnetic sensor or a resolver.

[0012] The stator 30 is cylindrical and positioned approximately in the axial center of the housing 20, along the inner circumference of the housing 20. The stator 30 is fixed to the inner surface of the housing 20 with respect to the axis O of the rotation shaft 11. The stator 30 constitutes part of the magnetic circuit and has a ring-shaped stator core 31 arranged radially opposite to the outer circumference of the rotor 40, and stator windings 32 wound around the stator core 31.

[0013] As shown in Fig. 2, the stator core 31 has an annular back yoke 33 and a plurality of teeth 34 protruding radially inward from the back yoke 33 and arranged at a predetermined distance in the circumferential direction. Slots 35 are formed between adjacent teeth 34. In the stator core 31, the teeth 34 are provided at equal intervals in the circumferential direction, and the stator winding 32 is wound around the teeth 34. Thereby, the conductors of the stator winding 32 are accommodated in each slot 35. In the present embodiment, the number of teeth 34 and the number of slots 35 are both set to "18". For convenience of explanation, each tooth 34 is assigned symbols T1 to 18 counterclockwise in the order of circumferential arrangement. When it is necessary to indicate the tooth number, the teeth 34 may also be described as teeth T1, T2, T3, ···. The stator winding 32 is held in a state of being accommodated in the slot 35 and generates magnetic flux when power (alternating current power) is supplied.

[0014] The stator core 31 is formed by using a plurality of steel plates (core sheets) which are thin plate-shaped magnetic bodies, and the plurality of steel plates are laminated in the axial direction of the stator core 31. The steel plate may be formed, for example, by press punching a strip-shaped electromagnetic steel plate material.

[0015] The rotor 40 forms part of the magnetic circuit, has a plurality of magnetic poles in the circumferential direction, and is arranged to face the stator 30 in the radial direction. In the present embodiment, the rotor 40 has 14 magnetic poles (i.e., 7 magnetic pole pairs). The rotor 40 includes a rotor core 41 made of a magnetic body and a plurality of permanent magnets 42 fixed to the rotor core 41. Specifically, as shown in Fig. 2, the rotor 40 includes a permanent magnet 42 as a magnet portion for each magnetic pole such that the polarities alternate in the circumferential direction, and the permanent magnet 42 is embedded in an accommodation hole provided along the axial direction in the rotor core 41.

[0016] The rotor 40 may have a well-known configuration, and may be, for example, an IPM (Interior Permanent Magnet) type rotor or an SPM (Surface Permanent Magnet) type rotor. Alternatively, a rotor on the field winding side may be used as the rotor 40. In this embodiment, an IPM type rotor is used. The rotating shaft 11 is inserted through the rotor 40 and fixed to the rotating shaft 11 so as to rotate integrally with the rotating shaft 11 around the rotating shaft 11.

[0017] A control device 50 is connected to the motor 10. The control device 50 is mainly composed of a microcomputer equipped with a CPU, ROM, RAM, and I / O, and various functions are realized by the CPU executing a program stored in the ROM. These various functions may be realized by hardware electronic circuits, or at least a part of them may be realized by software, i.e., processing executed on a computer.

[0018] The control device 50 has functions such as converting power from an external source (e.g., a battery) and supplying it to the motor 10 to generate driving force. In addition, the control device 50 has a function to control the motor 10 (such as current control) using information about the rotation angle input from the angle sensor 12.

[0019] Figure 3 shows the electrical configuration of the control device 50 in this embodiment.

[0020] In this embodiment, the stator winding 32 is composed of a first stator winding 32a and a second stator winding 32b, and the control device 50 is provided with a first inverter circuit 51 and a second inverter circuit 52 for each of the stator windings 32a and 32b. Each inverter circuit 51 and 52 is composed of a full-bridge circuit having the same number of upper and lower arms as the number of phases in the three-phase system. The control device 50 controls the current in each phase by turning on and off switching elements provided on each arm.

[0021] More specifically, the first inverter circuit 51 comprises three phases, U-phase, V-phase, and W-phase, each equipped with a series connection of an upper arm switch Sp and a lower arm switch Sn as switching elements. In this embodiment, voltage-controlled semiconductor switching elements are used as the upper arm switch Sp and lower arm switch Sn in each phase, specifically IGBTs. MOSFETs may also be used as switching elements. Freewheeling diodes Dp and Dn are connected in antiparallel to the upper arm switch Sp and lower arm switch Sn in each phase, respectively.

[0022] The high-potential side terminal (collector) of each phase's upper arm switch Sp is connected to the positive terminal of the battery. The low-potential side terminal (emitter) of each phase's lower arm switch Sn is connected to the negative terminal (ground) of the battery. The intermediate connection point between each phase's upper arm switch Sp and lower arm switch Sn is connected to one end of the phase winding of each phase in the first stator winding 32a. The first stator winding 32a has U-phase, V-phase, and W-phase windings, and in the first inverter circuit 51, one end of each of these phase windings is connected to the intermediate connection point of the upper and lower arm switches Sp and Sn, respectively.

[0023] The second inverter circuit 52 has the same configuration as the first inverter circuit 51, so a detailed explanation is omitted here. The second stator winding 32b has X-phase, Y-phase, and Z-phase windings, and in the second inverter circuit 52, one end of each of these phase windings is connected to the intermediate connection point of the upper and lower arm switches Sp and Sn, respectively.

[0024] The three-phase current supplied from the first inverter circuit 51 and the three-phase current supplied from the second inverter circuit 52 have a predetermined current phase difference from each other.

[0025] Figure 4 is a perspective view showing the specific configuration of the stator 30, and Figure 5 is a perspective view showing the configuration of the stator core 31. Note that the stator 30 shown in Figure 4 corresponds to the stator 30 shown in Figure 2.

[0026] In the stator 30, the stator core 31 is composed of a plurality of segmented cores 61, and the stator core 31 is formed into a cylindrical shape by arranging each segmented core 61 in a circumferential direction. Each segmented core 61 has teeth 34, and as each segmented core 61 is arranged in a circumferential direction, the teeth 34 and slots 35 are arranged alternately in the circumferential direction, as shown in Figure 2. In this embodiment, the stator core 31 is composed of 18 segmented cores 61. The stator winding 32 is constructed by winding conductor material around each tooth 34 by concentrated winding. It is preferable that adjacent segmented cores 61 in the circumferential direction are joined to each other by adhesive or the like.

[0027] Each segmented core 61 has a core body 62 which is a laminate of steel plates, and insulating members 63 and 64 made of insulating resin material or the like. The insulating members 63 and 64 are attached to one axial end and the other end (upper and lower sides in the figure) of the teeth 34, and a conductor material is wound in multiple layers across each insulating member 63 and 64, thereby winding a partial winding around the teeth 34.

[0028] In the configuration shown in Figure 4, the ends of the windings are drawn out from each winding wound around each tooth 34, and these winding ends are connected in a predetermined order by a wiring module (not shown) that is assembled to the coil end of the stator 30.

[0029] An example of the electrical configuration of the stator winding 32 is shown in Figure 6. Figure 6(a) shows the configuration of the U, V, and W phase windings in the first stator winding 32a, and Figure 6(b) shows the configuration of the X, Y, and Z phase windings in the second stator winding 32b. In these stator windings 32a and 32b, the phase windings of each phase are connected to each other by a star connection (Y connection).

[0030] As shown in Figure 6(a), the first stator winding 32a has partial windings U1, U2, U3, and U4 as U-phase phase windings, partial windings V1, V2, V3, and V4 as V-phase phase windings, and partial windings W1, W2, W3, and W4 as W-phase phase windings. One end of the series connection of partial windings U1 and U2, one end of the series connection of partial windings V1 and V2, and one end of the series connection of partial windings W1 and W2 are connected to each other at the neutral point N1a, and one end of the series connection of partial windings U3 and U4, one end of the series connection of partial windings V3 and V4, and one end of the series connection of partial windings W3 and W4 are connected to each other at the neutral point N1b.

[0031] Furthermore, as shown in Figure 6(b), the second stator winding 32b has partial windings X1, X2, X3, and X4 as X-phase phase windings, partial windings Y1, Y2, Y3, and Y4 as Y-phase phase windings, and partial windings Z1, Z2, Z3, and Z4 as Z-phase phase windings. One end of the series connection of partial windings X1 and X2, one end of the series connection of partial windings Y1 and Y2, and one end of the series connection of partial windings Z1 and Z2 are connected to each other at the neutral point N2a, and one end of the series connection of partial windings X3 and X4, one end of the series connection of partial windings Y3 and Y4, and one end of the series connection of partial windings Z3 and Z4 are connected to each other at the neutral point N2b.

[0032] In addition, the four sub-windings for each phase winding in each stator winding 32a and 32b may be connected in a star configuration, rather than being divided into two pairs and connected in a star configuration as described above. In this case, the neutral points (N1a, N1b) in the first stator winding 32a are combined into one, and similarly, the neutral points (N2a, N2b) in the second stator winding 32b are also combined into one.

[0033] Alternatively, in the first stator winding 32a, the phase windings U1~U4, V1~V4, and W1~W4 of each phase may be connected in series, and these three-phase series connections may be connected in a star configuration. Similarly, in the second stator winding 32b, the phase windings X1~X4, Y1~Y4, and Z1~Z4 of each phase may be connected in series, and these three-phase series connections may be connected in a star configuration. In each stator winding 32a and 32b, it is also possible to connect the phase windings of each phase using a delta connection instead of a star connection (y connection).

[0034] In the stator core 31, all 18 teeth 34 are arranged in groups of three that are circumferentially continuous, and each group of three teeth 34 is wound with partial windings of two phase windings that are in different phases, using a concentrated winding method. In this case, each group of three teeth is wound with two partial windings from the first stator winding 32a (U1~U4, V1~V4, W1~W4) and two partial windings from the second stator winding 32b (X1~X4, Y1~Y4, Z1~Z4). Specifically, in each group of teeth, one tooth 34 on each side in the circumferential direction is wound with a partial winding from the first stator winding 32a, while the other tooth 34 is wound with a partial winding from the second stator winding 32b. Furthermore, both partial windings of the first and second stator windings 32a and 32b are wound around the central tooth 34 of each tooth group.

[0035] Figure 7 shows the correspondence between each partial winding of the stator windings 32a and 32b and each tooth T1 to T18. In Figure 7, four partial windings are wound around each group of teeth (triple teeth), such as teeth T1 to T3, T4 to T6, T7 to T9, etc. For example, A partial winding W1 of the second stator winding 32b is wound around tooth T1. The teeth T2 are wound with a partial winding W2 of the second stator winding 32b and a partial winding X2 of the first stator winding 32a. A partial winding X1 of the first stator winding 32a is wound around tooth T3. The other tooth groups will not be explained, but each partial winding is wound in a similar manner, and each partial winding is wound on the first to third teeth of each tooth group as shown in the figure.

[0036] In rotating electric machines, noise and vibration due to torque ripple can be a problem. Since torque ripple mainly consists of the sixth or twelfth harmonic components, it is desirable to suppress these. Therefore, it is preferable to use the motor 10 with the above configuration and perform the following control in the control device 50.

[0037] In the motor 10 with the above configuration, The first teeth (T1, T4, T7, T10, T13, T16) of each tooth group are wound with the U-phase, V-phase, and W-phase partial windings (first coil body) of the first stator winding 32a. • On the second teeth (T2, T5, T8, T10, T14, T17) of each tooth group, a partial winding (second coil body) of either one phase from the first and second stator windings 32a and 32b is wound. The third teeth (T3, T6, T9, T12, T15, T18) of each tooth group are wound with the X-phase, Y-phase, and Z-phase partial windings (third coil body) of the second stator winding 32b.

[0038] In this configuration, the control device 50 sets the combined phase difference between the magnetomotive force generated by the partial winding of the first stator winding 32a wound around the second teeth and the magnetomotive force generated by the partial winding of the second stator winding 32b wound around the second teeth, such that the phase difference between the magnetomotive force of the second coil body of each phase and the phase difference between the magnetomotive force of the third coil body of each phase and the magnetomotive force generated by the second coil body of each phase are within a predetermined phase range including 20 degrees in electrical angle, or the phase difference between the magnetomotive force of the third coil body of each phase and the magnetomotive force generated by the partial winding of the second coil body of each phase and the magnetomotive force generated by the partial winding of the second stator winding 32b wound around the second teeth are within a predetermined phase range including 20 degrees in electrical angle. Alternatively, the control device 50 sets the combined phase difference between the current flowing through the partial winding of the first stator winding 32a wound around the second tooth and the current flowing through the partial winding of the second stator winding 32b wound around the second tooth. Details of this control are described in detail in Japanese Patent No. 7103299 filed by the applicant of this application.

[0039] As described above, the motor 10 of this embodiment has a stator 30 with a concentrated winding structure, and the number of magnetic poles of the rotor 40 is "14", and the number of slots of the stator 30 is "18". There is concern that radial vibrations of the 8th harmonic and 10th harmonic components will occur due to this combination of the number of magnetic poles and the number of slots. Figure 8(a) is a perspective view showing the stator core structure before countermeasures in this embodiment, and Figure 8(b) is a diagram showing the range in which radial acceleration due to the 8th and 10th harmonic components occurs in the stator core of Figure 8(a). Note that in Figure 8(a), each tooth 34 in the stator core 31 extends parallel to the axial direction, and the flange portion provided at the tip of the tooth is uniform on both sides in the circumferential direction.

[0040] The radial acceleration shown in Figure 8(b) is based on the results obtained by the inventor's analysis. At a position approximately 180° away in the circumferential direction, radial inward acceleration occurs, and at a position approximately 180° away in the circumferential direction, and approximately 90° away from the radial inward acceleration, radial outward acceleration occurs. In this case, a radial electromagnetic force is generated in the direction of elliptical deformation of the stator core 31, raising concerns about the generation of noise of the same order.

[0041] Therefore, in this embodiment, measures are taken to address the eighth and tenth order electrical radial vibrations. Below, a configuration in which a skew structure is formed at the tooth tip of the stator core 31 as a measure against radial vibration will be described. Figure 9 is a perspective view showing the stepped skew structure of the stator core 31. Figure 9 shows a configuration in which the insulating members 63 and 64 are removed from the configuration of Figure 5 (i.e., an assembly of core bodies 62).

[0042] The core body 62 has teeth 34 extending in the radial direction and a yoke portion 62a provided on one radial end thereof, and a flange portion 62b extending in the circumferential direction is provided at the tip of the teeth 34. The yoke portion 62a corresponds to the back yoke 33 of the stator core 31 shown in Figure 2.

[0043] Furthermore, the core body 62 is formed by joining multiple blocks in the axial direction (up and down direction in the figure). In this embodiment, the core body 62 is formed by joining four blocks in the axial direction, and the shape of the flange portion 62b at the tip of the teeth differs in each block that is adjacent to each other vertically. Specifically, in each block, the amount of protrusion of the flange portion 62b on both sides (left and right sides) in the circumferential direction differs with respect to the circumferential center position of the tooth 34, and the magnitude of the protrusion is reversed left and right in each block that is adjacent to each other vertically. In other words, the configuration in Figure 9 includes a first tooth block B1 in which the flange portion 62b is biased to one side in the circumferential direction, and a second tooth block B2 in which the flange portion 62b is biased to the other side in the circumferential direction, and these tooth blocks B1 and B2 are arranged alternately in the axial direction. It is preferable that the tooth blocks B1 and B2 are of the same shape, but are stacked with their axial orientations reversed.

[0044] The flange portion 62b of each core body 62 corresponds to a skewed portion with stepped skew. In each tooth block, the circumferential center position is the same in the coil winding portion (excluding the flange portion 62b). In this embodiment, the number of axial skew stages of the stator 30 is set to 4, but it is preferable to have 3 or more skew stages in the axial direction.

[0045] Figure 10 illustrates the skew angle of the stator core 31. Figure 10 is a plan view of the core body 62, showing the first tooth block B1 and the second tooth block B2 overlapping in the axial direction.

[0046] Here, L is the straight line connecting the circumferential tooth center position and the axis O (stator center point), P1 is the circumferential center position of the first tooth block B1 at the tooth tip, and P2 is the circumferential center position of the second tooth block B2. In this case, the angle θ1 formed by the straight line O-P1 on the first tooth block B1 side with respect to line L and the angle θ2 formed by the straight line O-P2 on the second tooth block B2 side with respect to line L are the same (θ1=θ2), and the angle θe, which is the sum of angles θ1 and θ2, is the skew angle.

[0047] The skew angle θe is the displacement angle of the circumferential center point of the flange portion 62b. Specifically, in order to suppress radial vibrations of the 8th and 10th electrical components, the skew angle θe should be set as follows: For countermeasures against the 8th electrical component, the ideal skew angle θe is 180° / 8 = 22.5°, and for countermeasures against the 10th electrical component, the ideal skew angle θe is 180° / 10 = 18°. Considering these factors, the skew angle θe should be set in the range of 14 to 23° in electrical angles.

[0048] According to the skew structure described above, the eighth and tenth order electrical radial electromagnetic forces generated in the stator 30 are canceled out, and consequently, radial vibration is suppressed. Figure 11 shows the relationship between radial vibration acceleration and skew angle θe at the point in the stator core 31 where the eighth and tenth order electrical radial vibration accelerations are maximum. As can be seen from Figure 11, there is a correlation between the skew angle θe and the magnitude of radial vibration acceleration, and it can be seen that the radial vibration acceleration can be reduced by adjusting the skew angle θe. In this embodiment, the radial vibration acceleration is reduced by setting the skew angle θe in the range of 14 to 23°.

[0049] According to the embodiment described in detail above, the following excellent effects can be obtained.

[0050] In a concentrated winding motor 10 with a rotor 40 having 14 magnetic poles and a stator 30 having 18 slots, the stator 30 is configured to be skewed to suppress radial vibrations of the 8th and 10th order electrical components. In this case, by adding the skewed structure, the radial electromagnetic force caused by the 8th and 10th order electrical components can be reduced, and deformation of the stator 30 can be suppressed. As a result, the quietness of the motor 10 with a specific number of magnetic poles and slots can be improved.

[0051] In rotating electric machines where radial vibration occurs in the stator 30, structural reinforcement by resin impregnation, for example, may be considered as a countermeasure. However, with the configuration that suppresses radial vibration as described above, structural reinforcement by resin impregnation, etc., becomes unnecessary, and cost reduction can be expected.

[0052] In the stepped skew structure of the stator 30, the skew angle θe is defined as the displacement angle of the circumferential center point of the flange portion 62b at the tip of the teeth, and this skew angle θe is set to a range of 14 to 23° in electrical angles. This effectively suppresses radial vibrations of the 8th and 10th electrical components.

[0053] In a configuration in which the tooth tips of the stator core 31 are given a stepped skew, the desired configuration can be achieved simply by changing the core sheet, which offers cost advantages. In this case, by flipping over the tooth blocks (or core sheets) that are stacked in the axial direction, the direction of deviation of the flange portion 62b at the tooth tip can be changed, minimizing the cost increase required to realize the skew structure.

[0054] The number of axial skew stages of the stator 30 was set to three or more, specifically to four. In this case, for example, the robustness of the radial vibration suppression effect against dimensional variations can be improved compared to the case where the number of skew stages is two.

[0055] (Other embodiments) The above embodiment may be modified as follows, for example.

[0056] As shown in Figure 12, the stator 30 may be a linear skew structure with a skew that is continuously inclined in the axial direction. In this case, the teeth 34 in the stator core 31 are provided to extend in a direction inclined with respect to the axial direction, and the center position P11 on one end of the tooth tip and the center position P12 on the other end of the tooth tip are offset in the circumferential direction. In this configuration, the protruding dimensions on both sides of the flange portion 62b at the tooth tip are uniform when viewed in the axial direction, for example, the protruding dimensions on one side and the other side in the circumferential direction are the same.

[0057] The skew angle θe is the angle formed by the line connecting the center position P11 on one axial end of the tooth tip and the stator center point (not shown) and the line connecting the center position P12 on the other axial end of the tooth tip and the stator center point. In a linear skew structure, the skew angle θe is preferably set in the range of 28 to 46° in electrical angles. The skew angle θe corresponds to the circumferential displacement angle caused by linear skew. That is, for countermeasures against the 8th electrical component, the ideal angle for the skew angle θe is 360° / 8 = 45°, and for countermeasures against the 10th electrical component, the ideal angle for the skew angle θe is 360° / 10 = 36°. Considering these factors, the skew angle θe is preferably set in the range of 28 to 46° in electrical angles. Even with the above linear skew structure, radial vibrations of the 8th and 10th electrical components can be effectively suppressed. Furthermore, even when a linear skew structure is used, there is a correlation between the skew angle θe and the magnitude of the radial vibration acceleration (see Figure 11), and the radial vibration acceleration can be reduced to a desired level within a predetermined angular range (electrical angle 28 to 46°).

[0058] Instead of making the stator 30 a skew structure, it is also possible to make the rotor 40 a skew structure. Specifically, as shown in Figure 13(a), in the rotor 40, the position of the magnetic pole center is shifted in a stepped manner in the axial direction for each magnetic pole arranged in the circumferential direction, and it is preferable that the skew angle θe, which is the angle of this shift, be set in the range of 14 to 23° in electrical angle. In Figure 13(a), a plurality of permanent magnets 42 are fixed to the outer circumferential surface of the rotor core 41, and each magnetic pole is composed of these permanent magnets 42. At each magnetic pole, the position of each permanent magnet 42 arranged in the axial direction is shifted in a stepped manner, resulting in a stepped skew structure. The skew angle θe is the angle between the line connecting the magnet center position and the rotation center point at one end in the axial direction and the line connecting the magnet center position and the rotation center point at the other end in the axial direction. In the illustrated configuration, there are two steps in the axial direction, but it is also possible to have three or more steps (for example, four steps).

[0059] Alternatively, as shown in Figure 13(b), the rotor 40 may be a linear skew structure with a skew that is continuously inclined in the axial direction. In this case, the permanent magnets 42 of each magnetic pole are provided to extend in a direction inclined with respect to the axial direction, and the skew angle θe, which is the circumferential displacement angle, is preferably set in the range of 28 to 46° in electrical angles.

[0060] It is also possible to use a rotating electric machine as the motor 10, in which the number of magnetic poles of the rotor 40 and the number of slots of the stator 30 are defined as follows. In motor 10, the number of magnetic poles is set to "22" and the number of slots to "18". In motor 10, the number of magnetic poles is set to "16" and the number of slots to "18". In motor 10, the number of magnetic poles is set to "20" and the number of slots to "18". In each of these rotating electric machines, it is preferable that the stator 30 or rotor 40 be skewed in order to suppress radial vibrations of the eighth and tenth order electrical components, as described above.

[0061] In the stator core 31, each segmented core 61 may have multiple teeth 34 in the circumferential direction. For example, a segmented core 61 may have three teeth 34. Alternatively, the stator core 31 may have a configuration that is not a segmented core structure, i.e., a single, indivisible annular structure in the circumferential direction.

[0062] In the above embodiment, the stator winding 32 has a configuration having a first stator winding 32a and a second stator winding 32b, for a total of 6 phase windings. However, this can be changed to a configuration where the stator winding 32 has 3 phase windings.

[0063] The rotating electric machine may be an outer rotor type instead of an inner rotor type. [Explanation of Symbols]

[0064] 10...rotating electric machine, 30...stator, 31...stator core, 32...stator winding, 34...teeth, 40...rotor.

Claims

1. A rotor (40) having multiple magnetic poles arranged in the circumferential direction, In a rotating electric machine (10) comprising a stator core (31) having a plurality of teeth (34) in the circumferential direction, and a stator (30) having multiphase stator windings (32) wound around the teeth by concentrated winding, The number of magnetic poles of the rotor is (18 ± 4), and the number of slots between the teeth is 18, or The rotor has (18 ± 2) magnetic poles and 18 slots between the teeth. The stator is configured with a stepped skew structure in which a stepped skew is applied in the axial direction. In the stator described above, a flange portion (62b) extending in the circumferential direction and provided at the tip of the teeth is a skew portion, and the skew angle, which is the displacement angle of the circumferential center point of the flange portion, is set in the range of 14 to 23° in electrical angles, thereby suppressing radial vibrations of the 8th and 10th order electrical components.

2. The rotating electric machine according to claim 1, wherein three or more skews are provided in the axial direction.

3. A rotor (40) having multiple magnetic poles arranged in the circumferential direction, In a rotating electric machine (10) comprising a stator core (31) having a plurality of teeth (34) in the circumferential direction, and a stator (30) having multiphase stator windings (32) wound around the teeth by concentrated winding, The number of magnetic poles of the rotor is (18 ± 4), and the number of slots between the teeth is 18, or The rotor has (18 ± 2) magnetic poles and 18 slots between the teeth. The stator is configured with a linear skew structure that is continuously skewed in the axial direction. A rotating electric machine in which radial vibrations of the 8th and 10th order electrical components are suppressed by setting the skew angle, which is the circumferential displacement angle, to a range of 28 to 46° in electrical angles.

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