Rotating electric machine

Abstract

The rotating electrical machine includes: a rotor having a plurality of magnetic poles arranged in a circumferential direction; and a stator having a stator core having a plurality of teeth in the circumferential direction, and a multi-phase stator winding wound around the teeth by concentrated winding. In a rotating electric machine, the number of magnetic poles of a rotor is 18 + / -4 and the number of slots between teeth is 18, or the number of magnetic poles of the rotor is 18 + / -2 and the number of slots between teeth is 18, and skew is applied to a stator or the rotor so as to suppress radial vibration of an eighth harmonic component and a tenth harmonic component.

Description

[0001] Cross-reference to Related Applications

[0002] This application is based on Japanese Application No. 2022-188690 filed on November 25, 2022, the contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a rotating electric machine. Background Art

[0004] As a rotating electric machine having concentrated winding coils, for example, a rotating electric machine described in Patent Document 1 is known. Patent Document 1 describes a rotating electric machine having a specific number of magnetic poles as a rotor and a specific number of slots between teeth in a stator. Specifically, a rotating electric machine having 14 magnetic poles and 18 slots, a rotating electric machine having 22 magnetic poles and 18 slots, a rotating electric machine having 16 magnetic poles and 18 slots, and a rotating electric machine having 20 magnetic poles and 18 slots are disclosed. In these rotating electric machines, by setting the phase difference of the magnetomotive forces in each coil body between phases within a specified phase range including an electrical angle of 20 degrees, high-order harmonic components of the 6th or 12th electrical order are canceled, and torque ripple can be suppressed.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 7103299.

[0008] Although the above Patent Document 1 was applied by the applicant of the present application, further research by the applicant of the present application has found that in a rotating electric machine having the above-described specific number of magnetic poles and slots, radial electromagnetic forces that cause elliptical deformation in the stator are generated due to the 8th harmonic component and the 10th harmonic component, resulting in radial vibration. In this case, problems such as noise occur in the rotating electric machine, and there is a concern that the quietness will be reduced. In addition, it was confirmed that such radial vibration is generated in a rotating electric machine having a specific number of magnetic poles and slots such as 14 poles and 18 slots, and there is no problem in a rotating electric machine having, for example, 8 poles and 12 slots. Summary of the Invention

[0009] The present disclosure has been made in view of the above problems, and an object thereof is to improve the quietness in a rotating electric machine having a specific number of magnetic poles and slots.

[0010] The rotating electric machine of the present disclosure includes:

[0011] a rotor having a plurality of magnetic poles arranged in the circumferential direction; and

[0012] A stator having a stator core and a polyphase stator winding, the stator core having a plurality of teeth in the circumferential direction, and the polyphase stator winding being wound around the teeth by concentrated winding.

[0013] The number of poles of the rotor is 18 ± 4, and the number of slots between the teeth is 18, or

[0014] The number of poles of the rotor is 18 ± 2, and the number of slots between the teeth is 18,

[0015] Skew is applied to the stator or the rotor in a manner that suppresses the radial vibration of the 8th harmonic component and the 10th harmonic component.

[0016] In a rotating electrical machine with a stator having a concentrated winding structure, in the case where the number of poles of the rotor is (18 ± 4) and the number of slots of the stator is 18, or the number of poles of the rotor is (18 ± 2) and the number of slots of the stator is 18, there is a concern that the radial electromagnetic force in the direction of elliptical deformation generated in the stator due to the 8th harmonic component and the 10th harmonic component may reduce the quietness. In this regard, in the above rotating electrical machine, a structure is provided in which skew is applied to at least one of the stator and the rotor in a manner that suppresses the radial vibration of the 8th harmonic component and the 10th harmonic component. In this case, by adding the skew structure, the radial electromagnetic force caused by the 8th harmonic component and the 10th harmonic component can be reduced, and the deformation of the stator can be suppressed. As a result, the quietness can be improved in a rotating electrical machine having a specific number of poles and slots. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above objects, other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings:

[0018] Figure 1 is a longitudinal sectional view of the electrical machine.

[0019] Figure 2 is a transverse sectional view of the electrical machine.

[0020] Figure 3 is a diagram showing the electrical structure of the control device.

[0021] Figure 4 is a perspective view of the stator.

[0022] Figure 5 is a perspective view showing the structure of the stator core.

[0023] Figure 6 is a winding structure diagram of the stator winding.

[0024] Figure 7 is a diagram showing the correspondence between each partial winding of the stator winding and the teeth.

[0025] Figure 8 It is a diagram showing the radial acceleration caused by the 8th component and the 10th component.

[0026] Figure 9 It is a three-dimensional diagram showing the segmented skewed structure of the stator core.

[0027] Figure 10 It is a diagram explaining the skewed angle of the stator core.

[0028] Figure 11 It is a diagram showing the relationship between the 8th harmonic, the 10th radial vibration acceleration, and the skewed angle.

[0029] Figure 12 It is a three-dimensional diagram showing the linear skewed structure of the stator core.

[0030] Figure 13 It is a three-dimensional diagram showing the skewed structure of the rotor. Detailed implementation manners

[0031] Hereinafter, each implementation manner will be described based on the drawings. In addition, among the following implementation manners, the same or equivalent parts to each other are denoted by the same reference signs in the drawings, and the description of the parts with the same reference signs is cited. In the present implementation manner, the motor 10 as a rotating electrical machine will be described as an example.

[0032] Figure 1 The shown motor 10 is a permanent magnet excitation type, specifically, a permanent magnet excitation type synchronous machine having a three-phase winding. That is, the motor 10 is a brushless motor. The three-phase winding can have two systems. The motor 10 includes: a housing 20, a stator 30 fixed to the housing 20, a rotor 40 rotating relative to the stator 30, and a rotating shaft 11 to which the rotor 40 is fixed. Hereinafter, in the present implementation manner, the axial direction represents the axial direction of the rotating shaft 11, the radial direction represents the radial direction of the rotating shaft 11, and the circumferential direction represents the circumferential direction of the rotating shaft 11.

[0033] The housing 20 is formed in a cylindrical shape, and the stator 30, the rotor 40, etc. are housed in the housing 20. Bearings 23 and 24 are provided in the housing 20, and the rotating shaft 11 is supported by the bearings 23 and 24 so as to be rotatable freely. The axis of the inner peripheral surface of the housing 20 is coaxial with the rotating shaft 11. An angle sensor 12 is provided on the top end side of the rotating shaft 11. The angle sensor 12 can be a magnetic sensor or a resolver.

[0034] The stator 30 is disposed cylindrically along the inner circumference of the outer housing 20 at a substantially central position in the axial direction of the outer housing 20. Further, the stator 30 is fixed to the inner peripheral surface of the outer housing 20 with the axis O of the rotation axis 11 as the center. The stator 30 forms a part of the magnetic circuit and includes a stator core 31 and a stator winding 32. The stator core 31 has an annular shape and is disposed radially opposite on the outer peripheral side of the rotor 40. The stator winding 32 is wound around the stator core 31.

[0035] As Figure 2 shown, the stator core 31 has an annular rear yoke 33 and a plurality of teeth 34. The plurality of teeth 34 project from the rear yoke 33 toward the radially inner side and are 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 arranged at equal intervals in the circumferential direction, and the stator winding 32 is wound around the teeth 34. Thus, the conductors of the stator winding 32 are accommodated in the respective slots 35. In the present embodiment, the number of teeth 34 and the number of slots 35 are each set to "18". For convenience of explanation, the teeth 34 are labeled with symbols T1 to T18 in the counterclockwise order of the circumferential arrangement. When it is necessary to indicate the tooth number, the tooth 34 is also described as tooth T1, T2, T3, …. The stator winding 32 is held in a state of being accommodated in the slot 35 and generates a magnetic flux by being supplied with electric power (alternating current).

[0036] The stator core 31 is formed by using a plurality of steel plates (iron core sheets) that are thin plate-shaped magnetic bodies and laminating the plurality of steel plates in the axial direction of the stator core 31. The steel plates can be formed, for example, by stamping and punching a strip-shaped electromagnetic steel sheet.

[0037] The rotor 40 forms a part of the magnetic circuit, has a plurality of magnetic poles in the circumferential direction, and is disposed so as to be radially opposite to the stator 30. 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 Figure 2 shown, the rotor 40 includes a permanent magnet 42 as a magnet portion for each magnetic pole in such a manner that the polarities alternate in the circumferential direction. The permanent magnet 42 is buried in a receiving hole provided along the axial direction of the rotor core 41.

[0038] The rotor 40 can be a known structure. For example, it can be an IPM (Interior Permanent Magnet) type rotor or an SPM (Surface Permanent Magnet) type rotor. Additionally, a rotor on the field winding side can be adopted as the rotor 40. In this embodiment, an IPM type rotor is adopted. The rotating shaft 11 passes through the rotor 40, and the rotor 40 is fixed to the rotating shaft 11 in such a manner that it rotates integrally with the rotating shaft 11 about the rotating shaft 11.

[0039] A control device 50 is connected to the electric machine 10. The control device 50 is configured with a microcomputer having a CPU, ROM, RAM, I / O, etc. as the main body. The CPU realizes various functions by executing programs stored in the ROM. In addition, various functions can be realized by an electronic circuit as hardware, or can be realized by at least part of software, that is, a process executed on a computer.

[0040] As functions possessed by the control device 50, for example, it has a function of converting electric power from the outside (such as a battery) and supplying it to the electric machine 10 to generate a driving force. Additionally, for example, the control device 50 has a function of controlling the electric machine 10 (such as current control) by using information related to the rotation angle input from the angle sensor 12.

[0041] Figure 3 It is a diagram showing the electrical structure of the control device 50 in this embodiment.

[0042] In this embodiment, the stator winding 32 is composed of a first stator winding 32a and a second stator winding 32b. In the control device 50, a first inverter circuit 51 and a second inverter circuit 52 are provided for each of the stator windings 32a, 32b. Each of the inverter circuits 51, 52 is composed of a full-bridge circuit having the same number of upper and lower arms as the number of phases of three phases. The control device 50 controls the current in each phase by turning on and off the switching elements provided in each arm.

[0043] For a detailed description, the first inverter circuit 51 includes a series connection body of an upper arm switch Sp and a lower arm switch Sn as switching elements in each of the three phases composed of the U phase, V phase, and W phase. In this embodiment, voltage-controlled semiconductor switching elements are used as the upper arm switch Sp and the lower arm switch Sn in each phase. Specifically, IGBTs are used. Additionally, MOSFETs can also be used as the switching elements. Freewheeling diodes (flyback diodes) Dp, Dn are respectively connected in antiparallel to the upper arm switch Sp and the lower arm switch Sn in each phase.

[0044] The high-potential side terminal (collector) of the upper-arm switch Sp of each phase is connected to the positive terminal of the battery. Additionally, the low-potential side terminal (emitter) of the lower-arm switch Sn of each phase is connected to the negative terminal (ground) of the battery. The intermediate connection points between the upper-arm switch Sp and the lower-arm switch Sn of each phase are respectively connected to one end of the phase windings of each phase in the first stator winding 32a. The first stator winding 32a has phase windings of U-phase, V-phase, and W-phase. In the first inverter circuit 51, one end of each of these phase windings is respectively connected to the intermediate connection points of the upper and lower arm switches Sp and Sn.

[0045] The second inverter circuit 52 has the same structure as the first inverter circuit 51, so detailed description thereof is omitted here. The second stator winding 32b has phase windings of X-phase, Y-phase, and Z-phase. In the second inverter circuit 52, one end of each of these phase windings is respectively connected to the intermediate connection points of the upper and lower arm switches Sp and Sn.

[0046] The three-phase currents supplied from the first inverter circuit 51 and the three-phase currents supplied from the second inverter circuit 52 have a prescribed current phase difference from each other.

[0047] Figure 4 is a perspective view showing the specific structure of the stator 30, Figure 5 is a perspective view showing the structure of the stator core 31. In addition, Figure 4 The stator 30 shown is equivalent to Figure 2 the stator 30 shown.

[0048] In the stator 30, the stator core 31 is composed of a plurality of segmented cores 61. By arranging and disposing the segmented cores 61 in the circumferential direction, the stator core 31 is formed into a cylindrical shape. Each segmented core 61 has teeth 34. By arranging the segmented cores 61 in the circumferential direction, as Figure 2 shown, the teeth 34 and the slots 35 are alternately arranged in the circumferential direction. In the present embodiment, the stator core 31 is composed of 18 segmented cores 61. The stator winding 32 is wound around each tooth 34 by concentrated winding using a wire material. The segmented cores 61 adjacent to each other in the circumferential direction can be joined to each other by adhesion or the like.

[0049] In addition, each segmented core 61 respectively has a core body 62 which is a steel plate laminate and insulating members 63, 64 made of an insulating resin material or the like. The insulating members 63, 64 are installed on one axial end side and the other end side (the upper side and the lower side in the figure) of the teeth 34. The wire material is wound around the teeth 34 by multi-layer winding in such a manner as to be laid on the insulating members 63, 64 to wind partial windings.

[0050] In Figure 4In the structure shown, winding ends are drawn out from the windings wound around the respective teeth 34, and these winding ends are connected in a prescribed order through a wiring module (not shown) for the coil ends mounted on the stator 30.

[0051] Figure 6 An example of the electrical structure of the stator winding 32 is shown. Figure 6 (a) thereof shows the structure of the phase windings of the U-phase, V-phase, and W-phase in the first stator winding 32a, Figure 6 (b) thereof shows the structure of the phase windings of the X-phase, Y-phase, and Z-phase in the second stator winding 32b. These stator windings 32a and 32b connect the phase windings of the respective phases to each other through a star connection (Y connection).

[0052] As Figure 6 shown in (a) thereof, the first stator winding 32a has partial windings U1, U2, U3, and U4 as the phase winding of the U-phase, has partial windings V1, V2, V3, and V4 as the phase winding of the V-phase, and has partial windings W1, W2, W3, and W4 as the phase winding of the W-phase. And, one end of the series connection body of the partial windings U1 and U2, one end of the series connection body of the partial windings V1 and V2, and one end of the series connection body of the partial windings W1 and W2 are connected to each other at the neutral point N1a, and one end of the series connection body of the partial windings U3 and U4, one end of the series connection body of the partial windings V3 and V4, and one end of the series connection body of the partial windings W3 and W4 are connected to each other at the neutral point N1b.

[0053] In addition, as Figure 6 shown in (b) thereof, the second stator winding 32b has partial windings X1, X2, X3, and X4 as the phase winding of the X-phase, has partial windings Y1, Y2, Y3, and Y4 as the phase winding of the Y-phase, and has partial windings Z1, Z2, Z3, and Z4 as the phase winding of the Z-phase. And, one end of the series connection body of the partial windings X1 and X2, one end of the series connection body of the partial windings Y1 and Y2, and one end of the series connection body of the partial windings Z1 and Z2 are connected to each other at the neutral point N2a, and one end of the series connection body of the partial windings X3 and X4, one end of the series connection body of the partial windings Y3 and Y4, and one end of the series connection body of the partial windings Z3 and Z4 are connected to each other at the neutral point N2b.

[0054] In addition, in addition to the structure in which the four partial windings of each phase winding in each of the stator windings 32a and 32b are separated in pairs as described above and are star-connected respectively, it is also possible to have a structure in which the four partial windings of each phase winding are star-connected on the basis of being connected in parallel in pairs. In this case, in the first stator winding 32a, the neutral points (N1a, N1b) are combined into one, and similarly in the second stator winding 32b, the neutral points (N2a, N2b) are combined into one.

[0055] In addition to this, it is also possible that in the first stator winding 32a, the partial windings U1 to U4, V1 to V4, and W1 to W4 of each phase are connected in series respectively, and the series-connected bodies of these three phases are connected by star connection, and similarly in the second stator winding 32b, the partial windings X1 to X4, Y1 to Y4, and Z1 to Z4 of each phase are connected in series respectively, and the series-connected bodies of these three phases are connected by star connection. In each of the stator windings 32a and 32b, instead of star connection (Y connection), the phase windings of each phase can also be connected by Δ connection.

[0056] In the stator core 31, among all 18 teeth 34, every three consecutive ones in the circumferential direction are taken as a group, and in each group of three teeth 34, the partial windings of two phase windings with different phases are wound by concentrated winding respectively. In this case, in each tooth group with three teeth as a group, two partial windings among the partial windings U1 to U4, V1 to V4, and W1 to W4 of the first stator winding 32a and two partial windings among the partial windings X1 to X4, Y1 to Y4, and Z1 to Z4 of the second stator winding 32b are wound in a distributed state. Specifically, in each tooth group, on one of the teeth 34 on both sides in the circumferential direction, the partial winding of the first stator winding 32a is wound, and on the other side of each tooth 34, the partial winding of the second stator winding 32b is wound. In addition, on the tooth 34 at the center of each tooth group, the partial windings of both the first stator winding 32a and the second stator winding 32b are wound.

[0057] Figure 7 It is a diagram showing the correspondence between the partial windings of the stator windings 32a and 32b and each tooth T1 to T18. In Figure 7 For each tooth group (three-connected teeth) such as T1 to T3, T4 to T6, T7 to T9,..., four partial windings are wound. For example:

[0058] On tooth T1, the partial winding W1 of the second stator winding 32b is wound;

[0059] On tooth T2, the partial winding W2 of the second stator winding 32b and the partial winding X2 of the first stator winding 32a are wound;

[0060] A partial winding X1 of a first stator winding 32a is wound around a tooth T3.

[0061] For other tooth groups, although the description is omitted, each partial winding is wound in the same manner, and in the first to third teeth of each tooth group, each partial winding is wound as shown in the figure.

[0062] In a rotating electric machine, noise and vibration due to torque ripple become problems. Torque ripple mainly consists of high-order harmonic components of the 6th electrical order or the 12th electrical order, so it is preferable to suppress these. Therefore, for the motor 10 having the above structure, control is performed in the control device 50 as follows.

[0063] In the motor 10 having the above structure:

[0064] Partial windings (first coil bodies) of the U-phase, V-phase, and W-phase of the first stator winding 32a are wound around the first teeth (T1, T4, T7, T10, T13, T16) of each tooth group;

[0065] Partial windings (second coil bodies) of any one of the first stator winding 32a and the second stator winding 32b are wound around the second teeth (T2, T5, T8, T10, T14, T17) of each tooth group;

[0066] Partial windings (third coil bodies) of the X-phase, Y-phase, and Z-phase of the second stator winding 32b are wound around the third teeth (T3, T6, T9, T12, T15, T18) of each tooth group.

[0067] Moreover, in this structure, the control device 50 sets the phase differences of the magnetomotive forces of the second coil bodies of each phase with respect to the magnetomotive forces of the first coil bodies of each phase and the phase differences of the magnetomotive forces of the third coil bodies of each phase with respect to the magnetomotive forces of the second coil bodies of each phase to be within a specified phase range including an electrical angle of 20 degrees, or the phase differences of the magnetomotive forces of the third coil bodies of each phase with respect to the magnetomotive forces of the first coil bodies of each phase and the phase differences of the magnetomotive forces of the second coil bodies of each phase with respect to the magnetomotive forces of the third coil bodies of each phase to be within a specified phase range including an electrical angle of 20 degrees, and sets the total phase difference between the magnetomotive force generated by the partial winding of the first stator winding 32a wound around the second tooth and the magnetomotive force generated by the partial winding of the second stator winding 32b wound around the second tooth. The total phase difference can be set, for example, within a range of electrical angles of 72 to 88 degrees. Alternatively, the control device 50 sets the total 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. In addition, the details of this control are described in detail in the Japanese Patent Publication No. 7103299 filed by the applicant of this application.

[0068] As described above, in the motor 10 of the present embodiment, the stator 30 has a concentrated winding structure, the number of magnetic poles of the rotor 40 is set to "14", and the number of slots of the stator 30 is set to "18". There is a concern that the combination of such a number of magnetic poles and slots may cause radial vibrations of higher harmonic components of the 8th harmonic and the 10th harmonic. Figure 8 (a) of is a perspective view showing the stator core structure before the countermeasure in the present embodiment, Figure 8 (b) of is shown in Figure 8 (a) of the stator core shows the range of the radial acceleration generated by the 8th component and the 10th component. In addition, in Figure 8 (a), in the stator core 31, the teeth 34 extend parallel to the axial direction, and the flange portions provided at the tip portions of the teeth are equal on both circumferential sides.

[0069] Figure 8 (b) of the radial acceleration shown is based on the result obtained by the analysis performed by the inventors of the present application. At positions separated by approximately 180° in the circumferential direction, a radial inward acceleration is generated toward the radial inside, and similarly, at positions separated by approximately 180° in the circumferential direction and shifted by approximately 90° from the radial inward acceleration, a radial outward acceleration is generated toward the radial outside. In this case, there is a concern that a radial electromagnetic force in the direction of elliptical deformation is generated in the stator core 31, and noise of the same order is generated.

[0070] Therefore, in the present embodiment, countermeasures against the radial vibrations of the 8th harmonic and the 10th harmonic are studied. Hereinafter, as a countermeasure against the radial vibration, a structure in which a skew structure is provided at the tip portion of the teeth of the stator core 31 will be described. Figure 9 (a) is a perspective view showing the segmented skew structure of the stator core 31. Figure 9 shows the structure obtained by removing the insulating members 63 and 64 from the structure of Figure 5 (i.e., the aggregate of the core bodies 62).

[0071] The core body 62 has teeth 34 extending in the radial direction and a yoke portion 62a provided on one radial end side thereof, and a flange portion 62b extending in the circumferential direction is provided at the tip portion of the teeth 34. The yoke portion 62a corresponds to Figure 2 the rear yoke 33 of the stator core 31 shown in.

[0072] In addition, the core body 62 is formed in a state where a plurality of blocks are connected in the axial direction (the vertical direction of the figure). In the present embodiment, the core body 62 is formed by connecting four blocks in the axial direction, and the shape of the flange portion 62b at the top end of the tooth is different in each block adjacent to each other. Specifically, in each block, the protrusion amount of the flange portion 62b on both sides (left and right sides) of the circumferential direction relative to the circumferential center position of the tooth 34 is different, and the size of the protrusion amount is opposite on the left and right in each block adjacent to each other. That is, in Figure 9 In the structure, the first tooth block B1 with the flange portion 62b biased to one side of the circumferential direction and the second tooth block B2 with the flange portion 62b biased to the other side of the circumferential direction are included, and these tooth blocks B1 and B2 are alternately arranged in the axial direction. In addition, the tooth blocks B1 and B2 can also use the same shape, and the axial directions are opposite to each other and overlap.

[0073] The flange portion 62b of each core body 62 corresponds to a skewed portion to which a segmented skew is applied. In addition, in each tooth block, the circumferential center position is the same in the coil winding portion (except for the flange portion 62b). In the present embodiment, the number of axially skewed segments of the stator 30 is four, but the number of axially skewed segments may be three or more.

[0074] Figure 10 It is a diagram for explaining the skew angle of the stator core 31 . Figure 10 It is a plan view of the core body 62 , and shows a state where the first tooth block B1 and the second tooth block B2 overlap in the axial direction.

[0075] Here, the straight line connecting the circumferential tooth center position and the axis O (stator center point) is set as L, and the circumferential center position of the first tooth block B1 is set as P1 in the tooth tip portion, and the circumferential center position of the second tooth block B2 is set as P2. In this case, the angle θ1 formed by the straight line O-P1 on the first tooth block B1 side with respect to the straight line L and the angle θ2 formed by the straight line O-P2 on the second tooth block B2 side with respect to the straight line L are the same angle (θ1=θ2), and the angle θe obtained by adding the angles θ1 and θ2 is the skew angle.

[0076] The skew angle θe is the offset angle of the circumferential center point of the flange portion 62b. Specifically, in order to suppress the radial vibration of the 8th harmonic component and the 10th harmonic component, the skew angle θe can be set as follows. That is, as a countermeasure for the 8th harmonic component, the electrical angle 180° / 8=22.5° is the ideal angle of the skew angle θe, and as a countermeasure for the 10th harmonic component, the electrical angle 180° / 10=18° is the ideal angle of the skew angle θe. In view of this, the skew angle θe can be set in the range of 14° to 23° in electrical angle.

[0077] According to the above-mentioned skew structure, radial electromagnetic forces of the 8th harmonic and the 10th harmonic generated in the stator 30 cancel each other out, thereby suppressing radial vibration. Figure 11 : is a graph showing the relationship between the radial vibration acceleration and the skew angle θe at the location where the radial vibration acceleration of the 8th harmonic and the 10th harmonic components is the maximum in the stator core 31. Figure 11 It can be seen that the skew angle θe is related to the magnitude of the radial vibration acceleration, and the radial vibration acceleration can be reduced by adjusting the skew angle θe. In this embodiment, the radial vibration acceleration can be reduced by setting the skew angle θe to a range of 14 to 23 degrees.

[0078] According to the present embodiment described in detail above, the following excellent effects can be obtained.

[0079] In the motor 10 of the concentrated winding structure in which the number of magnetic poles of the rotor 40 is set to "14" and the number of slots of the stator 30 is set to "18", a skewed structure is applied to the stator 30 to suppress radial vibration of the 8th harmonic component and the 10th harmonic component. In this case, by adding the skewed structure, the radial electromagnetic force caused by the 8th harmonic component and the 10th harmonic component can be reduced, and the deformation of the stator 30 can be suppressed. As a result, in the motor 10 having a specific number of magnetic poles and slots, quietness can be improved.

[0080] In addition, in a rotating electric machine that generates radial vibration in the stator 30, as a countermeasure, structural reinforcement such as resin impregnation is considered, but according to the structure that suppresses radial vibration as described above, structural reinforcement based on resin impregnation etc. is not required, and the effect of reducing costs can be foreseen.

[0081] In the segmented skew structure of the stator 30, the offset angle of the circumferential center point of the flange portion 62b at the tooth tip is set to a skew angle θe, and the skew angle θe is set to an electrical angle range of 14° to 23°. This can effectively suppress the radial vibration of the 8th and 10th harmonic components.

[0082] According to the structure of applying a stepwise skew to the tooth tip of the stator core 31, a desired structure can be realized only by changing the core sheet, which is considered to be cost-effective. In this case, by flipping the tooth blocks (or core sheets) overlapped in the axial direction, the offset direction of the flange portion 62b at the tooth tip can be changed, and the cost increase can be minimized while realizing the skew structure.

[0083] The number of axial skew stages of the stator 30 is set to three or more, specifically, to four. In this case, for example, compared with the case where the number of skew stages is set to two, the robustness of the radial vibration suppression effect against dimensional variations can be improved.

[0084] (Other embodiments)

[0085] The above-described embodiments can be modified as follows, for example.

[0086] As Figure 12 shown, the stator 30 can also be provided with a linear skew structure in which a skew that is continuously inclined in the axial direction is applied. In this case, in the stator core 31, the teeth 34 are arranged so as to extend in a direction inclined with respect to the axial direction, and a structure is formed in which the center position P11 on one axial end side and the center position P12 on the other axial end side in the tooth tip portion are offset in the circumferential direction. Further, in this structure, in the flange portion 62b of the tooth tip portion, the protruding dimensions on both circumferential sides are uniform when viewed in the axial direction. For example, the protruding dimensions may be the same on one circumferential side and the other circumferential side.

[0087] The skew angle θe is the angle formed by a straight line connecting the center position P11 on one axial end side in the tooth tip portion and the stator center point (not shown) and a straight line connecting the center position P12 on the other axial end side in the tooth tip portion and the stator center point. In the linear skew structure, the skew angle θe may be set in the range of 28° to 46° electrical degrees. The skew angle θe corresponds to the circumferential offset angle caused by the linear skew. That is, as a countermeasure against the 8th harmonic component, an electrical angle of 360° / 8 = 45° is the ideal angle for the skew angle θe, and as a countermeasure against the 10th harmonic component, an electrical angle of 360° / 10 = 36° is the ideal angle for the skew angle θe. In view of these, the skew angle θe may be set in the range of 28 to 46° electrical degrees. Even when the above-described linear skew structure is provided, the 8th harmonic component and the 10th harmonic component of the radial vibration can be suppressed well. Further, even when the linear skew structure is formed, there is a correlation between the skew angle θe and the magnitude of the radial vibration acceleration (see Figure 11 ), and in a specified angle range (28° to 46° electrical degrees), the radial vibration acceleration can be reduced to a desired level.

[0088] Instead of providing the stator 30 with a skew structure, the rotor 40 can also be provided with a skew structure. Specifically, as Figure 13 shown in (a) of Figure 13In (a) thereof, a plurality of permanent magnets 42 are fixed to the outer peripheral surface of the rotor core 41, and each magnetic pole is constituted by the permanent magnet 42. In each magnetic pole, the positions of the permanent magnets 42 arranged in the axial direction are stepped and offset to form a segmented skew structure. The skew angle θe is the angle formed by a straight line connecting the magnet center position on one axial end side and the rotation center point and a straight line connecting the magnet center position on the other axial end side and the rotation center point. In addition, in the illustrated structure, the number of segments in the axial direction is two, but it can also be three or more (for example, four).

[0089] In addition, as Figure 13 shown in (b) thereof, the rotor 40 may be a linear skew structure in which a skew continuously inclined in the axial direction is applied. In this case, the permanent magnets 42 of each magnetic pole are arranged so as to extend in a direction inclined with respect to the axial direction, and the skew angle θe as the circumferential offset angle may be set in the range of 28° to 46° electrical angle.

[0090] As the electric motor 10, a rotating electric machine that determines the number of magnetic poles of the rotor 40 and the number of slots of the stator 30 as follows can be used.

[0091] In the electric motor 10, the number of magnetic poles is set to "22" and the number of slots is set to "18".

[0092] In the electric motor 10, the number of magnetic poles is set to "16" and the number of slots is set to "18".

[0093] In the electric motor 10, the number of magnetic poles is set to "20" and the number of slots is set to "18".

[0094] In each of these rotating electric machines, similarly to the above, it is only necessary to apply a skew to the stator 30 or the rotor 40 to suppress the radial vibration of the 8th harmonic component and the 10th harmonic component.

[0095] In the stator core 31, each segmented core 61 may also have a plurality of teeth 34 in the circumferential direction. For example, the segmented core 61 may have three teeth 34. In addition, the stator core 31 may not be a segmented core structure, that is, it may be an integral annular structure that cannot be segmented in the circumferential direction.

[0096] In the above embodiment, the stator winding 32 has a structure having a first stator winding 32a and a second stator winding 32b and having a total of six-phase winding, and may be changed to a structure in which the stator winding 32 has a three-phase winding.

[0097] The rotating electric machine may be an outer rotor type rotating electric machine instead of an inner rotor type rotating electric machine.

[0098] The present disclosure has been described based on embodiments, but it should be understood that the present disclosure is not limited to these embodiments and structures. The present disclosure also includes various modifications and modifications within an equivalent range. In addition, various combinations and methods, and further other combinations and methods that include only one element, more than one element, or less than one element thereof are also included in the scope and thinking scope of the present disclosure.

Claims

1. A rotating electrical machine comprising: a rotor (40) having a plurality of magnetic poles arranged in a circumferential direction; and A stator (30) comprising a stator core (31) and a multi-phase stator winding (32), wherein the stator core (31) has a plurality of teeth (34) in the circumferential direction, and the multi-phase stator winding is wound around the teeth by concentrated winding. The rotating electrical machine (10) is characterized in that: The number of magnetic poles of the rotor is 18±4, and the number of slots between the teeth is 18, or The number of magnetic poles of the rotor is 18±2, and the number of slots between the teeth is 18, The stator or the rotor is skewed so as to suppress radial vibration of the eighth harmonic component and the tenth harmonic component.

2. The rotating electrical machine according to claim 1, characterized in that: The stator or the rotor is composed of a segmented skew structure with a step-shaped skew applied in the axial direction. In the stator, a flange portion (62b) provided at the top end of the tooth and extending in the circumferential direction is a skew portion, and a skew angle is set in the range of 14° to 23° in electrical angle, and the skew angle is a deviation angle of a circumferential center point of the flange portion, or In the rotor, the magnetic pole center position is shifted in a step-like manner in the axial direction for each magnetic pole arranged in the circumferential direction, and the skew angle as the shift angle is set to a range of 14° to 23° in electrical angle.

3. The rotating electrical machine according to claim 2, characterized in that: The skew is provided in three or more stages in the axial direction.

4. The rotating electrical machine according to claim 1, characterized in that: The stator or the rotor is composed of a linear skew structure to which a skew continuously inclined in the axial direction is applied, The skew angle, which is a deviation angle in the circumferential direction, is set within a range of 28° to 46° in electrical angle.

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