Rotating electric machine

Abstract

To provide a rotating electric machine that can suppress the decrease in rotational efficiency. [Solution] The rotating electric machine 1 comprises a stator core 10, a rotor core 20, and a coil 30 composed of conductors 31. The stator core 10 has a plurality of teeth 11 arranged along the circumferential direction D2 of the stator core 10, the teeth 11 have two end faces 12a, 12b spaced apart in the axial direction D3 of the stator core 10, the conductor 31 is wound around the teeth 11 through the end faces 12a, 12b, the coil 30 has a first point P located on one edge of the end faces 12a, 12b in the circumferential direction D2 and a second point Q located on the other edge of the end faces 12a, 12b in the circumferential direction D2, at least a second portion 33 between the first point P and the second point Q extends in the radial direction D1 or substantially radial direction D5, at least the second portion 33 is aligned with the second rotor portion 22 in the axial direction D3, and the coil 30 is not folded back in the radial direction D1 at the end faces 12a, 12b.

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 discloses a rotary electric motor (rotating electric machine). This rotary electric motor includes a stator core, a first rotor element that is arranged in the radial direction of the stator core and receives magnetic force, and a rotor that has a second rotor element that is arranged in the axial direction of the stator core and receives magnetic force. A coil is wound around the stator core so that magnetic flux penetrates in the radial direction from an end face of the stator core facing the first rotor element, and the coil has a coil end portion outside an end face in the axial direction of the stator core. The coil end portion is bent in the radial direction and overlaps the second rotor element when viewed from the axial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, as described above, a rotating electric machine provided with a coil having a coil end portion is known. In such a rotating electric machine, in the coil end portion, there are sections where current flows in opposite directions in the conductor, and torque that rotates in opposite directions may be generated. In this case, the rotation efficiency of the rotating electric machine decreases.

[0005] An object of the present invention is to provide a rotating electric machine capable of suppressing a decrease in rotation efficiency.

Means for Solving the Problems

[0006] (1) One aspect of the present invention is a rotating electric machine comprising an annular stator core, a rotor core rotatably disposed relative to the stator core, and a coil made of a wire, wherein the stator core has a plurality of teeth arranged along the circumferential direction of the stator core, the teeth have two end faces spaced apart in the axial direction of the stator core, the rotor core has a first rotor portion arranged radially with respect to the stator core, and a second rotor portion arranged axially with respect to the stator core, the wire is wound around the teeth through the end faces, the coil has a first point located on one circumferential edge of the end face and a second point located on the other circumferential edge of the end face, at least a portion between the first and second points extends radially or substantially radially, at least a portion is axially aligned with the second rotor portion, and the coil is not folded back radially at the end face.

[0007] In such a rotating electric machine, torque is generated to rotate the rotor core by the magnetic flux generated from the teeth of the stator core toward the second rotor section and the current flowing through the conductor of the coil located at the end face of the teeth. The first point of the coil is located at one edge in the circumferential direction on the end face of the teeth. The second point of the coil is located at the other edge in the circumferential direction on the end face of the teeth. At least a portion between the first and second points extends radially or substantially radially. The coil is not folded back radially at the end face of the teeth. In this case, there is no section at the end face of the teeth where the directions of the currents flowing through the conductors are opposite to each other, and the direction of the torque generated at the end face is unidirectional. Therefore, torques that cancel each other out in the rotational direction of the rotor core are not generated, and a decrease in the rotational efficiency of the rotating electric machine can be suppressed. Furthermore, the length of the coil conductor can be shortened, which can suppress power loss in the rotating electric machine.

[0008] (2) In (1) above, the coil may have a first portion extending in the circumferential or substantially circumferential direction and a second portion extending in the radial or substantially radial direction at either of the two end faces. In such a configuration, when current flows through the second portion of the coil's conductor extending in the radial or substantially radial direction at either of the two end faces of the tooth, the direction of the current flow will be perpendicular or substantially perpendicular to the circumferential direction, so that the direction of the torque generated at the end face coincides with the direction of rotation of the rotor core. Therefore, the rotational efficiency of the rotating electric machine can be improved.

[0009] (3) In (2) above, the coil may have the first part and the second part on the other of the two end faces. In such a configuration, the coil located on the other end face of the tooth has the same structure as the coil located on one end face of the tooth. In this case, there is no section on either of the two end faces of the tooth where the direction of the current flowing through the coil's conductors is in opposite directions, and the decrease in the rotational efficiency of the rotating electric machine can be further suppressed.

[0010] (4) In (2) above, the coil may extend in the circumferential or substantially circumferential direction at the other of the two end faces. In such a configuration, the coil located at the other end face of the tooth portion does not have a portion extending in the radial or substantially radial direction. Therefore, no torque is generated at the other end face in the rotational direction of the rotor core. As a result, it is not necessary to place the second rotor portion on the other end face side of the tooth portion, and the rotating electric machine can be made smaller. [Effects of the Invention]

[0011] According to the present invention, it is possible to suppress the decrease in rotational efficiency. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view showing a rotating electric machine according to the first embodiment of the present invention. [Figure 2] This is a plan view showing a coil with one layer of wire wound around the teeth of the stator core, along with a portion of the stator core. [Figure 3]This is a plan view showing a coil with multiple layers of wire wound around the teeth of the stator core, along with a portion of the stator core. [Figure 4] This is an enlarged perspective view showing the stator core with one turn of coil wire wound around the teeth. [Figure 5] This is an enlarged perspective view showing the state in which the coil wire is wound around the teeth of the stator core of a rotating electric machine according to a comparative example. [Figure 6] This is an enlarged perspective view showing the state in which the coil wire is wound around the teeth of the stator core of the rotating electric machine according to the second embodiment by one turn. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0014] (First Embodiment) Figure 1 is a cross-sectional view showing a rotating electric machine 1 according to a first embodiment of the present invention. Figure 2 is a plan view showing a coil 30 in which a single layer of conductor wire 31 is wound around the teeth 11 of the stator core 10, together with a part of the stator core 10. The rotating electric machine 1 is, for example, a motor that rotates using a three-phase alternating current. In one example, the rotating electric machine 1 is a radial gap motor.

[0015] The rotating electric machine 1 comprises a stator core 10, a rotor core 20, a coil 30, and a rotating shaft 40. The stator core 10 has an annular shape. Figure 1 shows a cross-section of the stator core 10 along the radial direction D1.

[0016] The radial direction refers to the direction toward the central axis L of the rotation axis 40, or the direction away from the central axis L of the rotation axis 40, in a plane perpendicular to the central axis L of the rotation axis 40. The radial direction D1 may also be perpendicular to the central axis of the annular stator core 10.

[0017] The inside in the radial direction D1 means the side facing the central axis L in the radial direction D1. The inside in the radial direction D1 is, for example, the side of the rotary shaft 40 with respect to the stator core 10. The outside in the radial direction D1 means the side away from the central axis L in the radial direction D1. The outside in the radial direction D1 is, for example, the side opposite to the rotary shaft 40 with respect to the stator core 10.

[0018] The circumferential direction means the direction along the axis around the central axis L of the rotary shaft 40. The circumferential direction D2 may be the direction along the axis around the central axis of the annular stator core 10.

[0019] The axial direction means the direction along the central axis L of the rotary shaft 40. The central axis L may be the central axis of the stator core 10 or the central axis of the rotor core 20. The radial direction D1, the circumferential direction D2, and the axial direction D3 are for convenience of explanation and do not limit the position or orientation of an object, etc.

[0020] In the rotating electric machine 1, when the stator including the stator core 10 is energized, a rotating magnetic field is generated. In the rotating electric machine 1, due to the rotating magnetic field of the stator, the rotor including the rotor core 20 rotates. As the rotor rotates, the rotary shaft 40 rotates.

[0021] The rotary shaft 40, for example, has a cylindrical or rod-like shape. The rotary shaft 40 is rotatably supported by a housing (not shown) by a bearing (not shown). The length of the rotary shaft 40 in the axial direction D3 is longer than the length of the rotor core 20 in the axial direction D3.

[0022] The stator core 10 is housed inside the housing. For example, the stator core 10 is fixed to the inner surface of the housing. The stator core 10 is disposed at a position away from the outside in the radial direction D1 from the rotary shaft 40. The stator core 10 is disposed so as to surround the rotary shaft 40.

[0023] As described above, the stator core 10, viewed from the axial direction D3, has an annular shape. The cross-section of the stator core 10 along the radial direction D1 is, for example, rectangular. The stator core 10 is made of, for example, a magnetic material.

[0024] The stator core 10 has multiple teeth 11. The teeth 11 are the portions around which the conductor 31 of the coil 30 is wound. The teeth 11 are located inside the stator core 10 in the radial direction D1. The teeth 11 protrude inward in the radial direction D1 of the stator core 10. The multiple teeth 11 are arranged along the circumferential direction D2 of the stator core 10. The multiple teeth 11 are arranged, for example, at equal intervals.

[0025] The teeth 11 are, for example, rectangular or nearly rectangular (see Figure 4). For example, the length of the teeth 11 in the axial direction D3 is longer than the length of the teeth 11 in the radial direction D1 and the length of the teeth 11 in the circumferential direction D2.

[0026] The tooth portion 11 has an end face 12a (one of two end faces) and an end face 12b (the other of two end faces). The two end faces 12a and 12b are spaced apart in the axial direction D3. The two end faces 12a and 12b face opposite each other in the axial direction D3. One end face 12a is located on one side of the axial direction D3, and the other end face 12b is located on the other side of the axial direction D3.

[0027] The end faces 12a and 12b are, for example, rectangular or substantially rectangular in shape. For example, the length of the end faces 12a and 12b in the radial direction D1 is longer than the length of the end faces 12a and 12b in the circumferential direction D2. The edges of the end faces 12a and 12b along the circumferential direction D2 may be curved to protrude outward in the radial direction D1.

[0028] The tooth portion 11 has two sides 13a and 13b. The two sides 13a and 13b are spaced apart in the circumferential direction D2. The two sides 13a and 13b face opposite each other in the circumferential direction D2. One side 13a is located on one side of the circumferential direction D2, and the other side 13b is located on the other side of the circumferential direction D2.

[0029] One side surface 13a faces the other side surface 13b of an adjacent tooth portion 11. The distance between one side surface 13a and the other side surface 13b of the adjacent tooth portion 11 is the width of the slot 14, which will be described next. Both side surfaces 13a and 13b connect end surfaces 12a and 12b.

[0030] A slot 14 is formed between two adjacent teeth 11 of the multiple teeth 11. The slot 14 is a space formed in the stator core 10. The multiple slots 14 are arranged in the circumferential direction D2. The multiple slots 14 are arranged, for example, at equal intervals.

[0031] Viewed from the axial direction D3, the edges of the slots 14 along the circumferential direction D2 are curved, for example, to protrude outward in the radial direction D1. Viewed from the axial direction D3, the length of the edge along the circumferential direction D2 of a slot 14 located inside the radial direction D1 is shorter than the length of the edge along the circumferential direction D2 of a slot 14 located outside the radial direction D1.

[0032] Multiple slots 14 and multiple teeth 11 are arranged alternately. The surfaces of the slots 14 facing the circumferential direction D2 are the side surfaces 13a and 13b of the teeth 11. The conductors 31 of the coil 30 are wound around the slots 14 and housed in layers.

[0033] Multiple openings 15 are formed on the inside of the stator core 10 in the radial direction D1. The openings 15 are located between the air gap G (described later) and the slot 14. The openings 15 are separated by two adjacent teeth 11. The openings 15 serve as the entrances to the slots 14. The conductors 31 of the coil 30 are wound around the teeth 11 through the openings 15.

[0034] The rotor core 20 is rotatably positioned relative to the stator core 10. The rotor core 20 is covered by a housing. The rotor core 20 has a first rotor section 21 and a second rotor section 22.

[0035] The first rotor portion 21 is located radially outward in a direction D1 relative to the rotation axis 40. The first rotor portion 21 is adjacent to the outer circumferential surface of the rotation axis 40. The first rotor portion 21 is arranged in the radial direction D1 relative to the stator core 10. The first rotor portion 21 is aligned with the stator core 10, with an air gap G (described later) in between.

[0036] The first rotor section 21 is located radially inward D1 from the stator core 10. For example, the rotating electric machine 1 is an inner rotor motor. The first rotor section 21 is located radially inward D1 between the rotation shaft 40 and the stator core 10. However, the first rotor section 21 may be located radially outward D1 from the stator core 10. In this case, the rotating electric machine 1 is an outer rotor motor.

[0037] The first rotor portion 21 is, for example, cylindrical. An insertion hole 21a is formed in the first rotor portion 21. The insertion hole 21a extends along the axial direction D3. The insertion hole 21a penetrates the first rotor portion 21. When viewed from the axial direction D3, the insertion hole 21a is located, for example, at the center of the first rotor portion 21.

[0038] The rotating shaft 40 is inserted through the insertion hole 21a. The first rotor section 21 surrounds the rotating shaft 40. The first rotor section 21 and the rotating shaft 40 may be an integrated unit or separate units.

[0039] An air gap G is formed between the outer circumferential surface 21b of the first rotor portion 21 and the inner circumferential surface 11a of the stator core 10. The outer circumferential surface 21b of the first rotor portion 21 is the surface of the first rotor portion 21 facing outward in the radial direction D1. The inner circumferential surface 11a of the stator core 10 is the surface of the stator core 10 facing inward in the radial direction D1.

[0040] The second rotor section 22 is positioned alongside the stator core 10 in the axial direction D3. The second rotor section 22 is positioned away from the stator core 10 in the axial direction D3. The second rotor section 22 is aligned with the first rotor section 21 in the axial direction D3. The rotating shaft 40 passes through the second rotor section 22.

[0041] The second rotor portion 22 is, for example, disc-shaped. The length from the central axis L to the outer circumference of the second rotor portion 22 is longer than the length from the central axis L to the outer surface 21b of the first rotor portion 21. The length of the second rotor portion 22 in the axial direction D3 is shorter than the length of the first rotor portion 21 in the axial direction D3.

[0042] The rotor core 20 has, for example, a plurality (two in one example) of second rotor sections 22. The plurality of second rotor sections 22 are arranged in the axial direction D3. The first rotor section 21 and the stator core 10 are positioned between the plurality of second rotor sections 22. The other configurations of the second rotor sections 22 are the same as those of the first rotor section 21.

[0043] The first rotor section 21 and the second rotor section 22 are separate components, but they may be integrated. Both the first rotor section 21 and the second rotor section 22 are equipped with permanent magnets.

[0044] The coil 30 is composed of multiple conductors 31. In the coil 30, for example, each of the multiple conductors 31 is a three-way wiring system through which one of the u-phase, v-phase, and w-phase currents flows.

[0045] The conductor 31 is wound around the teeth 11 of the stator core 10. A coil 30 is formed by winding the conductor 31 around the teeth 11. The conductor 31 is wound around the teeth 11 in the radial direction D1, the circumferential direction D2, and the axial direction D3. The coil 30 is formed by winding the conductor 31 around the end face 12a, the side surface 13b, the end face 12b, and the side surface 13a of the teeth 11. The coil 30 is, for example, several turns to several tens of turns.

[0046] Figure 3 is a plan view showing a coil 30, in which multiple layers of conductors 31 are wound around the teeth 11 of the stator core 10, along with a portion of the stator core 10. As shown in Figure 3, the coil 30 has multiple layers of conductors 31. In one example, the coil 30 has 5 to 15 layers of conductors 31.

[0047] A coil of one layer is formed by winding a certain number of wires 31. After one layer of wire 31 has been wound, a second layer of wire 31 is wound as the next layer. For example, the wire 31 is wound from the inside to the outside in the radial direction D1.

[0048] For example, after a wire 31 is wound around the teeth 11 of the stator core 10 from the inner end in the radial direction D1 to the center in the radial direction D1, a wire 31 forming the next layer is wound around the teeth 11. After the winding of the wire 31 reaches the center in the radial direction D1, the winding of the wire 31 may be folded back in the radial direction D1.

[0049] The second layer of coil is stacked on top of the first layer of coil. This process is repeated for the winding of the conductor 31 in the third layer and beyond. The coil 30, with multiple layers of conductor 31 wound around it, is stacked axially D3 at the end faces 12a and 12b, and circumferentially D2 at the side faces 13a and 13b. The conductor 31 stacked on the side faces 13a and 13b fills the slot 14.

[0050] Figure 4 is an enlarged perspective view showing the state in which the conductor wire 31 of the coil 30 is wound around the teeth 11 of the stator core 10 by one turn. As mentioned above, the conductor wire 31 is wound around the teeth 11 through the end faces 12a and 12b.

[0051] In the following description, we will primarily explain the state in which the conductor 31 of the coil 30 is wound around the tooth portion 11 by one turn. The coil 30 may have the conductor 31 wound around it by one turn, or it may have the conductor 31 wound around it by multiple turns. In either case, the coil will be referred to as coil 30.

[0052] The coil 30 has a first point P and a second point Q. The coil 30 has the first point P and the second point Q on at least one of the two end faces 12a and 12b. In this embodiment, the coil 30 has the first point P and the second point Q on both of the two end faces 12a and 12b.

[0053] The first point P and the second point Q are descriptive terms indicating specific locations on the conductor 31 of the coil 30, and do not mean that physical points actually exist on the conductor 31. The same applies to the third to seventh points, which will be described later.

[0054] The first point P is located on one edge of the end faces 12a and 12b of the tooth portion 11 in the circumferential direction D2. The first point P is located on the edge of the end faces 12a and 12b along the radial direction D1. For example, in Figure 4, the first point P is located on the left edge of the end faces 12a and 12b when viewed from the inside in the radial direction D1. The first point P is located inside the radial direction D1, beyond the center of the radial direction D1. The first point P may also be located at the beginning of the winding of the coil 30.

[0055] The second point Q is located on the other edge of the end faces 12a and 12b of the tooth portion 11 in the circumferential direction D2. The second point Q is located on the edge of the end faces 12a and 12b along the radial direction D1. For example, in Figure 4, the second point Q is located on the right edge of the end faces 12a and 12b when viewed from the inside in the radial direction D1. In other words, the second point Q is located on the edge of the end faces 12a and 12b opposite to the first point P in the circumferential direction D2. The second point Q is located, for example, outside the radial direction D1 than the central part of the radial direction D1.

[0056] At the end faces 12a and 12b of the tooth portion 11, the first point P is located on one side of the radial direction D1 relative to the second point Q. In this embodiment, the first point P is located inward in the radial direction D1 relative to the second point Q.

[0057] However, the first point P may be located outside the radial direction D1 of the second point Q. The first point P and the second point Q are not located side by side along the circumferential direction D2. The first point P and the second point Q are located offset from each other in the radial direction D1.

[0058] At the two end faces 12a and 12b of the tooth portion 11, the coil 30 has a first portion 32, a second portion 33, and a third portion 34. The first portion 32 extends in the circumferential direction D2 or substantially in the circumferential direction D4. Extending substantially in the circumferential direction D4 means including configurations in which the conductor 31 does not curve along the circumferential direction D2 but extends in a straight line or the like. The first portion 32 is located inward in the radial direction D1 from the center of the radial direction D1. The first portion 32 is, for example, linear.

[0059] The second portion 33 (at least a portion thereof) is located between the first point P and the second point Q. The second portion 33 extends in the radial direction D1 or substantially radial direction D5. Extending substantially radially in D5 means that the conductor 31 is not arranged parallel to the radial direction D1, but includes configurations in which it is inclined with respect to the radial direction D1 at an angle of error. An angle of error is, for example, less than 10°. In this case, for example, the second portion 33 is inclined to approach the edge of the end face 12a along the radial direction D1 as it moves outward in the radial direction D1.

[0060] The second portion 33 is located to one side of the circumferential direction D2, rather than to the center of the circumferential direction D2. For example, in Figure 4, the second portion 33 is positioned to the right of the circumferential direction D2 when viewed from the inside of the radial direction D1. The second portion 33 is, for example, linear in shape. The second portion 33 is aligned with the second rotor portion 22 in the axial direction D3.

[0061] The third portion 34 extends in the circumferential direction D2 or substantially in the circumferential direction D4. The third portion 34 is located, for example, outside the central part of the radial direction D1. The third portion 34 is, for example, linear in shape.

[0062] The third section 34 is located radially outward D1 from the first section 32. The first section 32 is connected to the second section 33, and the second section 33 is connected to the third section 34. The second section 33 is longer than both the first section 32 and the third section 34.

[0063] The coil 30 has a third point R. The third point R is located between the first point P and the second point Q. The third point R is located between the first part 32 and the second part 33. The third point R is the inflection point between the first part 32 and the second part 33. The third point R is aligned with the first point P in the circumferential direction D2. The third point R may be located radially outward from the first point P in the radial direction D1. In this case, the first part 32 may be inclined radially outward with respect to the circumferential direction D2 in the radial direction D1.

[0064] The coil 30 has a fourth point S. The fourth point S is located between the second point Q and the third point R. The fourth point S is located between the second part 33 and the third part 34. The fourth point S is the inflection point between the second part 33 and the third part 34. The fourth point S is aligned with the third point R in the radial direction D1. The fourth point S is aligned with the second point Q in the circumferential direction D2. The fourth point S may be located inside the radial direction D1 compared to the second point Q. In this case, the third part 34 may be inclined inward in the radial direction D1 with respect to the circumferential direction D2.

[0065] At the two end faces 12a and 12b of the tooth portion 11, the coil 30 exhibits a shape, for example, that is composed of multiple straight lines. The coil 30 exhibits a crank shape, for example. The coil 30 exhibits an L-shape in the section from the first point P to the fourth point S, and also exhibits an L-shape in the section from the third point R to the second point Q.

[0066] At the end faces 12a and 12b of the tooth portion 11, the coil 30 has one second portion 33. The third point R is not located radially inward D1 than the first point P. The fourth point S is not located radially outward D1 than the second point Q. The coil 30 is not folded back radially D1 at the end faces 12a and 12b.

[0067] The coil 30 is positioned outside the first point P in the radial direction D1, and inside the second point Q in the radial direction D1. The coil 30 is not positioned inside the first point P in the radial direction D1. The coil 30 is not positioned outside the second point Q in the radial direction D1. For example, at end faces 12a and 12b, the coil 30 is not U-shaped, V-shaped, or J-shaped. As a result, there is no section in the coil 30 that is folded back in the radial direction D1.

[0068] As described above, since the coil 30 is not folded back in the radial direction D1, there is no portion where the coil 30 (conductor 31) along the radial direction D1 is aligned in the circumferential direction D2. As a result, there is no section at the end faces 12a and 12b of the tooth portion 11 where the currents flowing through the conductor 31 of the coil 30 are in opposite directions. Consequently, torque for rotating the rotor core 20 can be generated at the end faces 12a and 12b.

[0069] The coil 30 has a coil end portion E for each turn. For each turn of the coil 30, the coil end portion E includes the starting portion and the ending portion of the coil 30. The starting portion includes the portion of the conductor 31 that extends a certain distance from one end which is the starting point of the coil 30. The ending portion includes the portion of the conductor 31 that extends a certain distance from the other end which is the ending point of the coil 30. The coil end portion E may also be the combined portion of the first portion 32, the second portion 33, and the third portion 34 of the coil 30, from the first point P to the second point Q.

[0070] The coils 30 located on the sides 13a and 13b of the tooth portion 11 are linear in shape. The coils 30 located on the sides 13a and 13b extend along the axial direction D3.

[0071] In the rotating electric machine 1 described above, when the stator core 10 is energized, current flows through the conductors 31 of the coil 30 wound around the teeth 11. Specifically, current flows in the following order: the first portion 32, the second portion 33, and the third portion 34 of the conductor 31 located on the end face 12a of the teeth 11; the conductor 31 located on the side surface 13a of the teeth 11; the third portion 34, the second portion 33, and the first portion 32 of the conductor 31 located on the end face 12b of the teeth 11; and the conductor 31 located on the side surface 13b of the teeth 11.

[0072] Here, when current flows through the second portion 33 of the conductor 31 located at the end face 12a of the tooth portion 11, according to Fleming's left-hand rule, a magnetic flux is generated from the end face 12a of the tooth portion 11 toward the second rotor portion 22 located on the end face 12a side, and a torque that rotates the rotor core 20 is generated in one direction.

[0073] When current flows through the second portion 33 of the conductor 31 located at the end face 12b of the tooth portion 11, according to Fleming's left-hand rule, a magnetic flux is generated from the end face 12b of the tooth portion 11 toward the second rotor portion 22 located on the end face 12b side, and a torque that rotates the rotor core 20 is generated in the same direction as the above torque.

[0074] Figure 5 is an enlarged perspective view showing the state in which the conductor 31X of the coil 30X is wound around the teeth 11 of the stator core 10 of the comparative example rotating electric machine 1X by one turn. The comparative example rotating electric machine 1X differs from the rotating electric machine 1 of the first embodiment in that the coil 30X has a fourth portion 35 and a fifth point T at the two end faces 12a and 12b of the teeth 11.

[0075] The fourth portion 35 is the portion of the coil 30X that extends radially in the direction D1. The fourth portion 35 is located on one edge in the circumferential direction D2 at the end faces 12a and 12b of the tooth portion 11. The fourth portion 35 is located on the opposite side of the second portion 33 in the circumferential direction D2.

[0076] The fourth section 35 is aligned with the second section 33 in the circumferential direction D2. The fourth section 35 is connected to the first section 32. Point P is the inflection point between the fourth section 35 and the first section 32.

[0077] The fifth point T is located on the edge of the end faces 12a and 12b of the tooth portion 11 along the radial direction D1. The fifth point T is located on the same side of the end faces 12a and 12b as the first point P in the circumferential direction D2. The fifth point T and the first point P are aligned in the radial direction D1.

[0078] In such a rotating electric machine 1X, at the end faces 12a and 12b of the teeth 11, there are second and fourth sections 33 and 35 in which current flows in opposite directions through the conductor 31X of the coil 30X, generating torque that rotates in opposite directions. In this case, the rotational efficiency of the rotating electric machine 1X decreases. Furthermore, since the coil 30X of the rotating electric machine 1X has a fourth section 35, power loss occurs in the fourth section 35, further reducing the rotational efficiency of the rotating electric machine 1X.

[0079] In contrast, in the rotating electric machine 1 of this embodiment, torque is generated to rotate the rotor core 20 by the magnetic flux generated from the teeth 11 of the stator core 10 toward the second rotor portion 22, and the current flowing through the conductor 31 of the coil 30 located at the end faces 12a and 12b of the teeth 11. The first point P of the coil 30 is located on one edge in the circumferential direction D2 at the end faces 12a and 12b of the teeth 11. The second point Q of the coil 30 is located on the other edge in the circumferential direction D2 at the end faces 12a and 12b of the teeth 11. The second portion 33, which is at least a part between the first point P and the second point Q, extends in the radial direction D1 or substantially radial direction D5. The coil 30 is not folded back in the radial direction D1 at the end faces 12a and 12b of the teeth 11. In this case, there are no sections at the end faces 12a and 12b of the tooth portion 11 where the direction of the current flowing through the conductor 31 is opposite to that of the other, and the direction of the torque generated at the end faces 12a and 12b is unidirectional. Therefore, no torques canceling each other out in the rotational direction of the rotor core 20 are generated, and a decrease in the rotational efficiency of the rotating electric machine 1 can be suppressed. Furthermore, since the length of the conductor 31 of the coil 30 can be shortened, power loss of the rotating electric machine 1 can be suppressed.

[0080] Furthermore, in this embodiment, at the two end faces 12a and 12b of the tooth portion 11, the coil 30 has a first portion 32 extending in the circumferential direction D2 or substantially circumferential direction D4, and a second portion 33 extending in the radial direction D1 or substantially radial direction D5. In this configuration, when current flows through the second portion 33 extending in the radial direction D1 or substantially radial direction D5 of the conductor 31 of the coil 30 at the two end faces 12a and 12b of the tooth portion 11, the direction of current flow becomes perpendicular or substantially perpendicular to the circumferential direction D4. Therefore, the direction of torque generated at the end faces 12a and 12b coincides with the rotation direction of the rotor core 20. Consequently, the rotational efficiency of the rotating electric machine 1 can be improved.

[0081] Furthermore, in this embodiment, the coil 30 located at the end face 12b of the tooth portion 11 has the same structure as the coil 30 located at the end face 12a of the tooth portion. In this case, there are no sections on both the two end faces 12a and 12b of the tooth portion 11 where the direction of the current flowing through the conductor 31 of the coil 30 is in opposite directions, and the decrease in the rotational efficiency of the rotating electric machine 1 can be further suppressed.

[0082] Furthermore, in this embodiment, the coil 30 exhibits a crank shape at the end faces 12a and 12b of the tooth portion 11. In this configuration, the structure of the coil 30 located at the end faces 12a and 12b can be simplified by having a first portion 32 and a third portion 34 extending in the circumferential direction D2 or substantially circumferential direction D4, and a second portion 33 extending in the radial direction D1 or substantially radial direction D5.

[0083] (Second Embodiment) Figure 6 is an enlarged perspective view showing the state in which the conductor 31A of the coil 30A is wound around the teeth 11 of the stator core 10 of the rotating electric machine 1A according to the second embodiment by one turn. The rotating electric machine 1A of the second embodiment differs from the rotating electric machine 1 of the first embodiment in that the conductor 31A of the coil 30A located at the end face 12b of the teeth 11 extends only in the circumferential direction D2 or substantially circumferential direction D4 of the stator core 10.

[0084] At the end face 12b of the tooth portion 11, the coil 30A has a sixth point U and a seventh point V. The sixth point U is located on one edge of the end face 12b in the circumferential direction D2. The sixth point U is located on the edge of the end face 12b along the radial direction D1.

[0085] The seventh point V is located on the other edge of the end face 12b in the circumferential direction D2. The seventh point V is located on the edge of the end face 12b along the radial direction D1. In other words, the seventh point V is located on the edge of the end face 12b opposite to the sixth point U in the circumferential direction D2.

[0086] Points 6U and 7V are located inside the radial direction D1, beyond the center of the radial direction D1. Points 6U and 7V are aligned with each other in the circumferential direction D2.

[0087] At the end face 12b of the tooth portion 11, the coil 30A extends in the circumferential direction D2 or substantially circumferential direction D4. At the other end face 12b, the coil 30A has a fifth portion 36. The fifth portion 36 extends in the circumferential direction D2 or substantially circumferential direction D4. The fifth portion 36 is located radially inward from the center of radial direction D1. The fifth portion 36 is linear in shape. The fifth portion 36 is the portion of the coil 30A located between the sixth point U and the seventh point V.

[0088] The coils 30A located on the sides 13a and 13b of the tooth portion 11 are linear in shape. The coils 30A located on the sides 13a and 13b are inclined with respect to the axial direction D3 and the radial direction D1.

[0089] As described above, in this embodiment, at the end face 12b of the tooth portion 11, the coil 30A extends in the circumferential direction D2 or substantially in the circumferential direction D4. In this configuration, the coil 30 located at the end face 12b of the tooth portion 11 does not have a portion extending in the radial direction D1. Therefore, no torque in the rotational direction of the rotor core 20 is generated at the end face 12b of the tooth portion 11. As a result, it is not necessary to arrange the second rotor portion 22 on the end face 12b side of the tooth portion 11, and thus the rotating electric machine 1 can be made smaller.

[0090] It should be noted that the present invention is not limited to the above embodiments. For example, in the above embodiments, the coils 30 and 30A are not folded back in the radial direction D1 at the two end faces 12a and 12b of the tooth portion 11, but the invention is not particularly limited to such a configuration. For example, the coils 30 and 30A do not need to be folded back in the radial direction D1 at only one of the two end faces 12a and 12b.

[0091] Furthermore, in the above embodiment, the coils 30 and 30A have a shape in which multiple straight lines are combined at the two end faces 12a and 12b of the tooth portion 11, but are not limited to such a shape. For example, the coils 30 and 30A may be configured such that a single straight line is arranged at the two end faces 12a and 12b. In this case, the first point P and the second point Q are connected by a single straight line.

[0092] Furthermore, in the above embodiment, the coils 30 and 30A have a shape formed by combining multiple straight lines at the two end faces 12a and 12b of the tooth portion 11. However, the coils 30 and 30A may have a shape formed by combining curves at the two end faces 12a and 12b. In this case, the coils 30 and 30A may have, for example, an S-shape. [Explanation of symbols]

[0093] 1,1A...rotating electric machine, 10...stator core, 11...tooth section, 12a,12b...end face, 20...rotor core, 21...first rotor section, 22...second rotor section, 30,30A...coil, 31,31A...conductor, 32...first part, 33...second part, P...first point, Q...second point, D1...radial direction, D2...circumferential direction, D3...axial direction, D4...approximately circumferential direction, D5...approximately radial direction.

Claims

1. A rotating electric machine comprising a stator core having an annular shape, a rotor core rotatably arranged relative to the stator core, and a coil made of conductive wires, The stator core has a plurality of teeth arranged along the circumferential direction of the stator core, The tooth portion has two end faces that are spaced apart in the axial direction of the stator core, The rotor core has a first rotor portion arranged radially with respect to the stator core, and a second rotor portion arranged axially with respect to the stator core. The aforementioned conductor is wound around the tooth portion, passing through the end face. The coil has a first point located on one circumferential edge of the end face and a second point located on the other circumferential edge of the end face. At least a portion between the first point and the second point extends in the radial or substantially radial direction, At least one portion of the above is aligned with the second rotor portion in the axial direction, The coil is a rotating electric machine in which the end face is not folded back in the radial direction.

2. The rotating electric machine according to claim 1, wherein at either of the two end faces, the coil has a first portion extending in the circumferential direction or substantially circumferential direction and a second portion extending in the radial direction or substantially radial direction.

3. The rotating electric machine according to claim 2, wherein the coil has the first portion and the second portion at the other of the two end faces.

4. The rotating electric machine according to claim 2, wherein the coil extends in the circumferential direction or substantially circumferential direction at the other of the two end faces.

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