Rotary electric machine

Abstract

To provide a rotary electric machine which can improve the density of magnetic fluxes in a torque generation place while suppressing the induction voltage when the rotor is making rapid rotations.SOLUTION: The rotary electric machine includes: a stator having a plurality of stator teeth provided at predetermined intervals in a circumferential direction and projecting radially inward; and a rotor provided radially inside the stator. A plurality of grooves are formed on the outer peripheral surface of the rotor. The number of the grooves corresponds to the number of the stator teeth that generate magnetic force for attracting the rotor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] Interior Permanent Magnet Synchronous Motors (IPMSM) and Synchronous Reluctance Motors (SynRM) are widely known as drive motors mounted on electrically powered vehicles such as hybrid vehicles (HVs) and electric vehicles (EVs).These motors can improve magnetic flux density and torque by adjusting the orientation of the magnetic flux using a flux barrier, which is an air gap placed inside the rotor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-142735 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the magnetic flux density improves and the amount of magnetic flux flowing through the rotor increases, the induced voltage increases when the rotor rotates at high speeds. When the induced voltage increases, the current flowing through the stator decreases, which may result in a decrease in torque when the rotor rotates at high speeds.

[0005] An object of the present invention is to provide a rotating electric machine that can improve the magnetic flux density at the torque generating location while suppressing the induced voltage when the rotor is rotating at high speed. [Means for solving the problem]

[0006] To achieve the above object, a rotating electric machine according to the present invention includes a stator and a rotor. The stator has a plurality of stator teeth arranged at predetermined intervals in the circumferential direction and protruding radially inward. The rotor is arranged radially inward of the stator. A plurality of grooves are formed in the outer peripheral surface of the rotor. The number of grooves corresponds to the number of stator teeth that generate magnetic force to attract the rotor. [Effects of the Invention]

[0007] According to the present invention, the rotating electric machine can suppress the induced voltage when the rotor rotates at high speed, while improving the magnetic flux density at the torque generating location. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the configuration of a rotating electric machine according to an embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a portion F2 in FIG. 1 in the rotating electric machine of the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of the flow of magnetic flux in part F3 of FIG. 1 in the rotating electric machine of the above embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the flow of magnetic flux in a rotating electric machine of a comparative example. [Figure 5] FIG. 5 is a graph comparing the maximum torque of the rotating electrical machine of the above embodiment with a comparative example. [Figure 6] FIG. 6 is a graph comparing the induced voltage at high rotation speed of the rotating electric machine of the above embodiment with a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment] A rotating electric machine according to this embodiment will be described in detail below with reference to the accompanying drawings. The configuration of the embodiment described below, as well as the actions and results (effects) brought about by this configuration, are merely examples and are not limited to the following description. Note that in this specification, ordinal numbers are used only to distinguish between parts and components and do not indicate order or priority. Furthermore, this embodiment is an example in which the rotating electric machine of the present invention is applied to an interior permanent magnet synchronous motor.

[0010] The outline and structure of a rotating electric machine according to this embodiment will be described below. Fig. 1 is a cross-sectional view showing an example of the configuration of a rotating electric machine 1 according to one embodiment. The rotating electric machine 1 according to this embodiment is used, for example, as a power generating motor or a drive motor for a hybrid vehicle or an electric vehicle.

[0011] The rotating electric machine 1 is a magnet-interior synchronous motor in which a rotating magnetic field generated by an AC current applied to the stator winding attracts the permanent magnets of the rotor, causing the rotor to rotate at the same speed as the rotating magnetic field. The rotating electric machine 1 is also a variable magnetic flux motor in which the magnetic flux of the rotating magnetic field can be changed by changing the AC current applied to the stator winding.

[0012] As shown in FIG. 1 , the rotating electric machine 1 includes a stator 10 and a rotor 11. The stator 10 generates a magnetic force that rotates the rotor 11. The stator 10 has a plurality of stator teeth 101 that are arranged at predetermined intervals around the circumferential direction of the rotor 11 and that protrude from an annular portion of the stator 10 toward the radially inward direction of the rotor 11, and a coil 102. The plurality of stator teeth 101 extend in the radial direction of the rotor 11. Hereinafter, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the direction of the rotation axis Ax of the rotor 11, the radial direction of the rotor 11, and the circumferential direction of the rotor 11.

[0013] The coils 102 are wound around each of the multiple stator teeth 101. The coils 102 include coils 102a, 102b, and 102c through which currents of different phases flow. The rotating electric machine 1 is driven by passing, for example, three-phase AC current through each of the coils 102a, 102b, and 102c. The number of phases of the AC current flowing through the coils 102 does not matter.

[0014] The rotor 11 is provided radially inside the stator 10. The rotor 11 is rotatably installed inside the stator 10 via an air gap. The rotor 11 is rotatable around a rotation axis Ax. The rotor 11 is formed, for example, from a copper plate. Magnetic flux generated by a three-phase alternating current flowing through the coils 102 flows radially through the stator teeth 101, forming a rotating magnetic field. This rotating magnetic field magnetically attracts permanent magnets 1112 (described later), causing the rotor 11 to rotate.

[0015] A plurality of grooves are formed on the outer peripheral surface of rotor 11. The number of grooves corresponds to the number of stator teeth 101 that generate a magnetic force for attracting rotor 11. In this embodiment, the number of grooves is the same as the number of stator teeth 101 that generate a magnetic force for attracting rotor 11. This will be described in detail below with reference to FIG. 2.

[0016] FIG. 2 is an enlarged cross-sectional view of the rotating electric machine 1 of the embodiment, showing an enlarged portion F2 in FIG. 1 . In the example of FIG. 2 , the rotor 11 has eight salient pole portions 111 protruding radially outward. The salient pole portions 111 are spaced apart from one another in the circumferential direction. Each of the eight salient pole portions 111 is formed in a substantially rectangular parallelepiped shape. A plurality of grooves are formed on the outer circumferential surface of each of the eight salient pole portions 111. More specifically, as shown in FIG. 2 , the plurality of grooves include two first flux barriers 1114 and two second flux barriers 1115. The first flux barriers 1114 are grooves located near the circumferential center of each salient pole portion 111. The second flux barriers 1115 are grooves located other than near the circumferential center of each salient pole portion 111. Two first flux barriers 1114 are located between the two second flux barriers 1115, sandwiching the circumferential center (d-axis ad). Grooves are spaces filled with air, and therefore have low magnetic permeability. In other words, the space in which the grooves are formed has high magnetic resistance. For this reason, magnetic flux that flows through the interior of the rotor 11 and reaches the grooves has difficulty passing through the interior of the grooves. The grooves utilize this property of being difficult for magnetic flux to pass through to control the direction of the magnetic flux inside the rotor 11. In this embodiment, the d-axis ad indicates an axis set in the direction of the magnetic poles of the rotor 11 (radial direction).

[0017] The first flux barrier 1114 penetrates the salient pole portion 111 in the axial direction. The first flux barrier 1114 extends on the outer peripheral surface of the salient pole portion 111 and forms a generally elliptical shape that is recessed radially inward. The first flux barrier 1114 further has a shape that bulges toward the d-axis ad. The first flux barrier 1114 is provided between a magnet insertion hole 1111 (described later) and the outer peripheral surface of the salient pole portion 111.

[0018] The second flux barrier 1115 axially penetrates the salient pole portion 111. The second flux barrier 1115 extends on the outer peripheral surface of the salient pole portion 111 and forms a generally elliptical shape recessed radially inward. The second flux barrier 1115 is provided between a magnet insertion hole 1111 (described later) and the outer peripheral surface of the salient pole portion 111.

[0019] In this embodiment, the sum of the number of first flux barriers 1114 and the number of second flux barriers 1115 is the same as the number of stator teeth 101 that generate a magnetic force for attracting the rotor 11. More specifically, each salient pole portion 111 has two first flux barriers 1114 and two second flux barriers 1115, and the sum of the number of first flux barriers 1114 and the number of second flux barriers 1115 in one salient pole portion 111 is four. On the other hand, in the stator teeth 101 facing one salient pole portion 111, the number of stator teeth 101a that generate a magnetic force for attracting the rotor 11 is four, which is equal to the sum of the number of first flux barriers 1114 and the number of second flux barriers 1115 in one salient pole portion 111.

[0020] In each of the multiple salient pole portions 111, the circumferential length L1 between the first flux barriers 1114 located near the circumferential center is greater than the circumferential width L3 of the stator tooth 101, and the circumferential length between the adjacent first flux barriers 1114 and second flux barriers 1115 other than near the center, and the length L2 between the circumferential end of the salient pole portion 111 and the second flux barrier 1115 adjacent to that end, are the same as the circumferential width L3 of the stator tooth.

[0021] The salient pole portion 111 further includes a third flux barrier 1116, which is a hole penetrating the salient pole portion 111 in the axial direction. The third flux barrier 1116 is provided radially outside the magnet insertion hole 1111 and communicates with the magnet insertion hole 1111. The third flux barrier 1116 has a substantially triangular shape that protrudes radially outward. As described above, the first flux barrier 1114 has a shape that bulges toward the d-axis ad. In the above-described structure, the third flux barrier 1116, which has a substantially triangular shape that protrudes radially outward, is formed near the center of the salient pole portion 111 in the circumferential direction. Therefore, the structure of the salient pole portion 111 has a circumferential length L1 between the first flux barriers 1114 that is greater than the circumferential width L3 of the stator teeth 101, thereby ensuring a path for magnetic flux flowing near the third flux barrier 1116 inside the rotor 11.

[0022] A magnet insertion hole 1111 is formed near the radially outer end of the salient pole portion 111. The magnet insertion hole 1111 is located near the radially outer end of the salient pole portion 111. The magnet insertion hole 1111 penetrates the rotor 11 in the axial direction and is formed in a substantially rectangular parallelepiped shape extending circumferentially. The circumferential width of the magnet insertion hole 1111 is slightly shorter than the circumferential width of the salient pole portion 111. The rotating electric machine 1 is provided with one magnet insertion hole 1111 for each salient pole portion 111. In other words, the rotating electric machine 1 has eight magnet insertion holes 1111.

[0023] A pair of permanent magnets 1112, which are magnetic poles, are embedded in the magnet insertion hole 1111. The pair of permanent magnets 1112 are formed in a substantially rectangular parallelepiped shape. The pair of permanent magnets 1112 are arranged in the circumferential direction with the magnet insertion hole 1111 between them.

[0024] The pair of permanent magnets 1112 form the same magnetic poles. For example, if one of the pair of permanent magnets 1112 has a magnetic north pole on the radially outer side and a magnetic south pole on the radially inner side, the other permanent magnet 1112 adjacent to that permanent magnet 1112 also has a magnetic north pole on the radially outer side and a magnetic south pole on the radially inner side. The pair of permanent magnets 1112 in Fig. 2 have a magnetic north pole on the radially outer side and a magnetic south pole on the radially inner side.

[0025] Furthermore, the pair of permanent magnets 1112 included in each of two adjacent salient pole portions 111 form magnetic poles oriented in different directions. For example, if the pair of permanent magnets 1112 included in a certain salient pole portion 111 has a magnetic north pole on the radially outer side and a magnetic south pole on the radially inner side, the pair of permanent magnets 1112 included in another salient pole portion 111 adjacent to that salient pole portion 111 has a magnetic south pole on the radially outer side and a magnetic north pole on the radially inner side.

[0026] The magnet insertion hole 1111, the pair of permanent magnets 1112, the first flux barrier 1114, the second flux barrier 1115, and the third flux barrier 1116 are arranged symmetrically with respect to the d-axis ad.

[0027] The number of second flux barriers 1115 is not limited to two and may be, for example, four. When the number of second flux barriers 1115 is four, two first flux barriers 1114 are provided between two of the four second flux barriers 1115 that are located closer to the center in the circumferential direction, with the center of the rotor 11 in the circumferential direction (d-axis ad) sandwiched between them.

[0028] (Flow of magnetic flux in rotating electrical machines) Next, the flow of magnetic flux in the rotating electric machine 1 will be described with reference to Fig. 3. In the following description, the direction in which the rotor 11 rotates is counterclockwise in Fig. 3, and the same applies to Fig. 4. Fig. 3 is a diagram illustrating an example of the flow of magnetic flux at part F3 in Fig. 1 in the rotating electric machine 1 of this embodiment. In Fig. 3, a pair of permanent magnets 1112a are formed with an N pole on the radially outer side and an S pole on the radially inner side.

[0029] As an example of magnetic flux flow, first, a path will be described in which magnetic flux generated by a three-phase AC current flowing through the coil 102 passes through a pair of permanent magnets 1112a provided on the salient pole portion 111a shown in Fig. 3, passes near the permanent magnets 1112a toward the radially outward direction, and reaches the four stator teeth 101a. In the following description, in order to distinguish between each salient pole portion 111 and the components of the salient pole portion 111, any of the symbols a to c may be assigned to the components. Furthermore, the four stator teeth 101a are stator teeth among the multiple stator teeth 101 that generate magnetic force for attracting the rotor 11.

[0030] The magnetic flux flowing near the pair of permanent magnets 1112a provided on the salient pole portion 111a avoids the two first flux barriers 1114a and two second flux barriers 1115a, which are located radially outside the pair of permanent magnets 1112a and are spaces with high magnetic resistance, and travels inside the salient pole portion 111a toward each of the four stator teeth 101a located in the direction of travel (arrows A1, A2, A3, and A4). The magnetic flux that reaches each of the four stator teeth 101a then passes between the multiple coils 102 and heads toward the annular portion of the stator 10. The rotating magnetic field formed by the above-described magnetic flux flow magnetically attracts the four stator teeth 101a to the outer periphery of the salient pole portion 111a. This causes the rotor 11 to rotate.

[0031] (Action and effect of rotating electric machines) Next, the effect of magnetic flux concentration in the rotating electric machine 1 will be described. In this embodiment, the number of grooves (first flux barriers 1114 and second flux barriers 1115) formed on the outer peripheral surface of the rotor 11 corresponds to the number of stator teeth 101 that generate magnetic force to attract the rotor 11. More specifically, the number of grooves (first flux barriers 1114 and second flux barriers 1115) formed on the outer peripheral surface of the rotor 11 is the same as the number of stator teeth 101 that generate magnetic force to attract the rotor 11. In the above-described structure, magnetic flux flowing through the rotor 11 toward the stator 10 avoids the first flux barriers 1114 and the second flux barriers 1115 and flows concentratedly through the four stator teeth 101a, which are torque generating locations. Therefore, the rotating electric machine 1 can suppress the amount of magnetic flux flowing through the rotor 11, thereby suppressing induced voltage during high-speed rotation of the rotor 11 and concentrating the magnetic flux at the torque generating locations to improve magnetic flux density.

[0032] Here, as a comparative example, a configuration in which no grooves are formed on the outer peripheral surface of the salient pole portion is assumed. FIG. 4 is a diagram illustrating an example of the flow of magnetic flux in a rotating electric machine 1A of the comparative example. As shown in FIG. 4, the salient pole portion 111A of the rotor 11A of the rotating electric machine 1A differs from the salient pole portion 111 of the rotating electric machine 1 in that it does not have two first flux barriers 1114 and two second flux barriers 1115. Therefore, the magnetic flux flowing through the salient pole portion 111A flows approximately uniformly radially outward around the outer peripheral portion of the salient pole portion 111A facing the stator teeth 101 (arrow B1). In other words, the magnetic flux from the inside of the salient pole portion 111a toward the stator 10 does not concentrate on each of the four stator teeth 101a, which are torque generating locations.

[0033] In contrast, in the rotating electric machine 1 of this embodiment, a plurality of grooves (two first flux barriers 1114 and two second flux barriers 1115) are formed on the outer peripheral surface of the rotor 11. Furthermore, the number of grooves (first flux barriers 1114 and second flux barriers 1115) formed on the outer peripheral surface of the rotor 11 is the same as the number of stator teeth 101 that generate magnetic force to attract the rotor 11. With this structure, the magnetic flux flowing through the rotor 11 flows along the shapes of the first flux barriers 1114 and the second flux barriers 1115 and is concentrated on the stator teeth 101a. In other words, the rotating electric machine 1 of this embodiment can suppress induced voltage while concentrating magnetic flux at torque generation locations to improve magnetic flux density, and ultimately improve torque.

[0034] FIG. 5 is a graph comparing the maximum torque of the rotating electric machine 1 of this embodiment with the shape of the comparative example. As shown in FIG. 5, the rotating electric machine 1 of this embodiment can exert the same maximum torque as the shape of the comparative example. Also, FIG. 6 is a graph comparing the induced voltage at high rotation speed of the rotating electric machine of the above embodiment with the comparative example. As shown in FIG. 6, the rotating electric machine 1 of this embodiment can reduce the induced voltage more than the shape of the comparative example.

[0035] Furthermore, in this embodiment, the circumferential length between adjacent grooves (the first flux barrier 1114 and the second flux barrier 1115) and the length L2 between the end of the salient pole portion 111 in the circumferential direction and the second flux barrier 1115 adjacent to that end are the same as the circumferential width L3 of the stator tooth 101. In the above-described structure, the magnetic flux flowing through the rotor 11 toward the stator 10 is concentrated in the four stator teeth 101a, which are the torque generation locations. Therefore, the rotating electric machine 1 can improve the magnetic flux density by concentrating the magnetic flux in the torque generation locations while suppressing the induced voltage when the rotor 11 is rotating at high speeds.

[0036] In this embodiment, in each of the multiple salient pole portions 111, the circumferential length L1 between two grooves (first flux barriers 1114 and 1114) located near the circumferential center is greater than the circumferential width L3 of the stator tooth 101, and the circumferential length between adjacent grooves (first flux barriers 1114 and 1115) other than near the circumferential center and the length L2 between an end of the salient pole portion 111 in the circumferential direction and the second flux barrier 1115 adjacent to that end are the same as the circumferential width L3 of the stator tooth 101. In this embodiment, the first flux barrier 1114 has a shape that bulges toward the d-axis ad. In addition, a third flux barrier 1116 having a substantially triangular shape that protrudes radially outward is formed near the center of the salient pole portion 111 in the circumferential direction. In the above-described structure, the structure of the salient pole portion 111 is such that the circumferential length L1 between the first flux barriers 1114 is greater than the circumferential width L3 of the stator teeth 101, thereby ensuring a path for magnetic flux flowing near the third flux barrier 1116 inside the rotor 11.

[0037] (Variation 1) The rotor 11 may have a shape that does not have the salient pole portion 111. When the rotor 11 does not have the salient pole portion 111, the outer peripheral surface of the rotor 11 is formed in an annular shape. When the rotor 11 does not have the salient pole portion 111, two first flux barriers 1114 and two second flux barriers 1115 are formed on the outer peripheral surface of the rotor 11.

[0038] (Variation 2) The sum of the number of first flux barriers 1114 and the number of second flux barriers 1115 does not have to match the number of stator teeth 101 that generate magnetic force to attract the rotor 11, and may be any number necessary to achieve the purpose of this embodiment.

[0039] (Variation 3) The shape of the grooves (first flux barrier 1114 and second flux barrier 1115) is not limited to a substantially elliptical shape, and may be, for example, a substantially V-shape that opens radially outward or a teardrop shape that bulges radially inward.

[0040] (Variation 4) The rotating electric machine 1 can change the number of stator teeth 101a that generate magnetic force to attract the rotor 11, for example, by controlling the current flowing through the coil 102. For example, in the above-described embodiment, the number of stator teeth 101a that generate magnetic force to attract the rotor 11 is four. However, the rotating electric machine 1 can also change the number of stator teeth 101a that generate magnetic force to three by controlling the current flowing through the coil 102. When the number of stator teeth 101a is three, the three stator teeth 101a are located at stator teeth 101a1, 101a2, and 101a3 that are closest to the rotational direction (counterclockwise direction) of the rotor 11 among the stator teeth 101 that face the outer peripheral surface of the salient pole portion 111a. Furthermore, the magnetic flux flowing through the rotor 11 is mainly directed in the direction (arrows A1, A2, and A3) where the three stator teeth 101a1, 101a2, and 101a3 are located. On the other hand, the magnetic flux flowing through the rotor 11 is less likely to flow in the direction of arrow A4. That is, the magnetic flux flowing through the rotor 11 toward the stator 10 is more concentrated in the direction in which the rotor 11 rotates. In this case, for example, the number of grooves (first flux barriers 1114 and second flux barriers 1115) in each salient pole portion 111 can be set to three. In this case, the number of stator teeth 101 a that generate a magnetic force for attracting the rotor 11 is the same as the number of grooves in each salient pole portion 111, so the rotating electric machine 1 can concentrate the magnetic flux at the torque generation location, thereby improving the magnetic flux density. That is, the number of grooves in each salient pole portion 111 may be any number within a range in which the number of stator teeth 101 a that generate a magnetic force for attracting the rotor 11 changes, and may be any number equal to or less than the maximum number of stator teeth 101 a that generate a magnetic force for attracting the rotor 11.

[0041] (Variation 5) The circumferential length L2 between adjacent grooves (first flux barrier 1114 and second flux barrier 1115) other than near the circumferential center does not necessarily have to match the circumferential width L3 of stator tooth 101.

[0042] (Variation 6) The circumferential width L3 of the stator teeth 101 and the circumferential width of the grooves (first flux barrier 1114, second flux barrier 1115) can be increased or decreased within a design range. For example, when the circumferential width L3 of the stator teeth 101 is larger than the standard value, the circumferential widths of the first flux barrier 1114 and the second flux barrier 1115 are reduced by the amount by which the circumferential width L3 of the stator teeth 101 is larger than the standard value.

[0043] In other words, the circumferential width L3 of the stator teeth 101 and the circumferential width of the grooves (first flux barrier 1114, second flux barrier 1115) can be determined so that the circumferential length L1 between the first flux barriers 1114 located near the circumferential center is greater than the circumferential width L3 of the stator teeth 101, and the circumferential length between adjacent first flux barriers 1114 and second flux barriers 1115 other than near the circumferential center, and the length L2 between the end of the salient pole portion 111 in the circumferential direction and the second flux barrier 1115 adjacent to that end, are equivalent to the circumferential width L3 of the stator teeth 101.

[0044] (Variation 7) The salient pole portion 111 may have a shape that does not include the third flux barrier 1116. When the salient pole portion 111 does not have the third flux barrier 1116, the two first flux barriers 1114 have a substantially elliptical shape and do not bulge toward the d-axis ad. In the above-described structure, as in this embodiment, the magnetic flux flowing through the rotor 11 toward the stator 10 is concentrated at the four stator teeth 101a, which are torque generation locations. In other words, the rotating electric machine 1 can concentrate the magnetic flux at the torque generation locations while suppressing the induced voltage when the rotor 11 is rotating at high speed.

[0045] (Variation 8) The shape of the magnet insertion hole 1111 (permanent magnet 1112) is not limited to a substantially rectangular parallelepiped shape, and may be formed, for example, in a substantially V-shape that is symmetrical with respect to the d-axis ad and opens radially outward. Furthermore, two magnet insertion holes 1111 may be provided side by side in the circumferential direction, and the two magnet insertion holes 1111 may form a substantially V-shape that opens radially outward.

[0046] Although the embodiments of the present invention have been described above, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. This novel embodiment can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Furthermore, this embodiment is included within the scope and spirit of the invention, and is also included in the inventions and their equivalents described in the claims. [Explanation of symbols]

[0047] 1.1A rotating electric motor 10 Stator 11,11A rotor 101, 101a, 101a1, 101a2, 101a3 stator teeth 111,111A,111a Salient pole part 1114,1114a First Flux Barrier 1115,1115a Second Flux Barrier 1116 Third Flux Barrier ad d axis Ax rotation axis L1 Circumferential length between first flux barriers L2: The circumferential length between the first flux barrier and the second flux barrier that are adjacent to each other in the salient pole portion other than near the center in the circumferential direction, and the length in the circumferential direction between the end of the salient pole portion and the second flux barrier that is adjacent to that end L3 Circumferential width of stator teeth A1, A2, A3, A4, B1 Direction of magnetic flux flow

Claims

1. a stator having a plurality of stator teeth arranged at predetermined intervals in a circumferential direction and protruding radially inward; a rotor provided radially inside the stator, A plurality of grooves are formed on the outer circumferential surface of the rotor, The number of the grooves corresponds to the number of the stator teeth that generate a magnetic force for attracting the rotor. Rotating electric motor.

2. a stator having a plurality of stator teeth arranged at predetermined intervals in a circumferential direction and protruding radially inward; a rotor provided radially inside the stator, the rotor has a plurality of salient poles that protrude radially outward, A plurality of grooves are formed on the outer circumferential surface of each of the plurality of salient pole portions, In each of the plurality of salient pole portions, The circumferential length between two of the grooves located near the circumferential center is the same as or greater than the circumferential width of the stator teeth, and the circumferential length between adjacent grooves other than near the center and the circumferential length between an end of the salient pole portion and the groove adjacent to that end are the same as the circumferential width of the stator teeth. Rotating electric motor.

3. The number of the grooves corresponds to the number of the stator teeth that generate a magnetic force for attracting the rotor. The rotating electric machine according to claim 2 .

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