Rotary electric machine

Abstract

To provide a rotary electric machine in which a facing area of a salient pole can be increased.SOLUTION: A rotary electric machine 100 includes: a rotor 2 having a magnet 24 provided with a plurality of magnetic poles 26 and rotatable about a rotation axis; a stator 4 having a stator core 3 facing the magnetic poles 26; and a coil 8 provided on the stator core 3. The stator core 3 has: tooth portions 33 facing the magnetic poles 26; and a yoke portion 34 connecting the tooth portions 33. The coil 8 is disposed on the yoke portion 34.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A rotating electrical machine including a rotor and a stator arranged to face each other is known. For example, Patent Document 1 describes a rotating electrical machine including a rotor and a stator arranged to face axially with a gap therebetween with respect to the rotor. The stator includes a plurality of stator cores arranged in the circumferential direction and a plurality of coils wound around the periphery of each stator core.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the viewpoint of improving the performance of a rotating electrical machine, when the facing area of the salient poles (tooth portions) of the stator facing the magnetic poles of the rotor is large, it is more advantageous than when the facing area of the salient poles is small. However, when coils are wound around the salient poles of the stator, the salient poles have to be made smaller by the amount of the coil arrangement space, and the facing area of the salient poles becomes small. Therefore, there is room for improvement in the rotating electrical machine described in Patent Document 1 from the viewpoint of increasing the facing area of the salient poles.

[0005] An object of the present invention is to provide a rotating electrical machine capable of further increasing the facing area of the salient poles in view of such problems.

Means for Solving the Problems

[0006] In order to solve the above problems, a rotating electrical machine according to an aspect of the present invention includes a rotor having a magnet provided with a plurality of magnetic poles and rotatable about a rotation axis, a stator having a stator core facing the magnetic poles, and a coil provided in the stator core. The stator core has a tooth portion facing the magnetic poles and a yoke portion connecting the tooth portions. The coil is disposed in the yoke portion.

[0007] In addition, any combination of the above components, or those obtained by mutually replacing the components and expressions of the present invention among methods, systems, etc. are also effective as aspects of the present invention.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a rotating electrical machine capable of further increasing the facing area of salient poles.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. In the embodiments and modifications, the same or equivalent components and members are denoted by the same reference numerals, and repeated explanations are appropriately omitted. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, some of the members that are not important for explaining the embodiments in each drawing are omitted and shown.

[0011] Also, terms including ordinal numbers such as first and second are used to describe various components, but this term is used only for the purpose of distinguishing one component from another, and the components are not limited by this term.

[0012] [First Embodiment] With reference to the drawings, the configuration of the rotating electrical machine 100 according to the first embodiment will be described. In this specification, an electromechanical machine having a rotating part is referred to as a "rotating electrical machine", and the rotating electrical machine includes a motor, a generator, and a motor-generator. The rotating electrical machine 100 in this example can be used as a motor, a generator, or a motor-generator.

[0013] FIG. 1 is a side view schematically showing an example of the rotating electrical machine 100. The rotating electrical machine 100 includes a rotor 2 and a stator 4. The rotor 2 is provided so as to be rotatable about the rotation axis La. Hereinafter, the direction parallel to the rotation axis La is referred to as the axial direction (the vertical direction in the figure), the direction orthogonal to the rotation axis La in a plane orthogonal to the rotation axis La is referred to as the radial direction, and the circumferential direction of a circle centered on the rotation axis La is referred to as the "circumferential direction". In FIG. 1, the upper side may be referred to as "up", and the opposite side may be referred to as "down". Such a notation of directions does not limit the posture of the rotating electrical machine 100, and the rotating electrical machine 100 can be used in any posture.

[0014] In the example of FIG. 1, the rotating electrical machine 100 is an axial-gap type motor including a rotor 2 and a stator 4 that face each other with an air gap therebetween in the axial direction. The rotor 2 is rotatably supported about the rotation axis La by bearing means 28.

[0015] The rotor 2 has a rotor yoke 22, an annular magnet 24, and a shaft 12. The rotor yoke 22 is a disk made of soft magnetic material. The shaft 12 is a rod-shaped stainless steel member extending along the rotation axis La, passing through the center of the rotor yoke 22, and fixed to the rotor yoke 22.

[0016] The magnet 24 is fixed to the lower surface of the rotor yoke 22, for example, by adhesion. The magnet 24 has a plurality of magnetic poles 26 that function as drive magnetic poles on the surface facing the stator core 3 in the axial direction. For example, the plurality of magnetic poles 26 are 10 magnetic poles arranged at predetermined intervals in the circumferential direction. As an example, the magnet 24 of the present embodiment is a neodymium magnet mainly composed of neodymium, iron, and boron. The magnet 24 supplies magnetic flux (hereinafter simply referred to as "magnetic flux F") from the magnetic poles 26 to the magnetic path of the stator core 3. For the magnetic poles 26, the side from which the arrow of the magnetic flux F exits is the N pole, and the side into which it enters is the S pole. The external magnetic flux F of the magnet 24 exits from the N pole on the lower surface of the magnet 24, passes from one end to the other end of the stator core 3, and enters the S pole on the lower surface of the magnet 24.

[0017] The stator support member 32 is a disk-shaped member having a side facing the magnet 24 and a side opposite thereto, and is made of a non-magnetic material. As this non-magnetic material, a resin material, a carbon material, a glass material, a non-magnetic metal material, a ceramic material, etc. can be adopted. A bearing means 28 is provided at the center of the stator support member 32, and the shaft 12 is inserted vertically into the bearing means 28. The bearing means 28 is a rolling bearing. With this configuration, the stator 4 can rotatably support the rotor 2.

[0018] Refer also to FIG. 2. FIG. 2 is a developed view showing the stator 4 developed. The stator 4 has a stator support member 32, a plurality of stator cores 3, and a plurality of coils 8. In the present embodiment, corresponding to each of the U phase, V phase, and W phase, one stator core 3 and one coil 8 are provided for each phase. The coils 8 may be arranged in a dispersed manner at a plurality of locations. The U-phase coil 8-U is wound around the U-phase stator core 3, the V-phase coil 8-V is wound around the V-phase stator core 3, and the W-phase coil 8-W is wound around the W-phase stator core 3. In other words, the stator 4 in this example has 3 stator cores 3 and 3 coils 8. Note that in FIG. 1, one stator core 3 and one coil 8 are shown.

[0019] The stator core 3 functions as a magnetic path for allowing the magnetic flux F supplied from the magnetic pole 26 to pass therethrough. The stator core 3 is fixed to the stator support member 32 using an adhesive at predetermined angles (e.g., 120°) in the circumferential direction.

[0020] The stator core 3 has two teeth portions 33 facing the magnetic pole 26 and a yoke portion 34 connecting the two teeth portions 33. The teeth portion 33 may be referred to as a salient pole. The yoke portion 34 is a rod-shaped or plate-shaped portion connected to the two teeth portions 33 and extends substantially parallel to the stator support member 32. The magnetic flux F flows into one teeth portion 33, flows through the yoke portion 34, and flows out from the other teeth portion 33. The magnetic flux F mainly flows in the axial direction in the teeth portion 33 and flows in the crossing direction crossing the axial direction in the yoke portion 34. The coil 8 is disposed on the yoke portion 34. The portion of the yoke portion 34 where the coil 8 is disposed is called the disposed portion 35.

[0021] The coil 8 is composed of three-phase coils 8-U, 8-V, and 8-W in which resin-coated copper wires are wound around the outer periphery of the yoke portion 34. The three-phase coils 8-U, 8-V, and 8-W are, for example, three-phase star-connected.

[0022] The stator core 3 can be manufactured from various known magnetic materials such as plate materials, foil materials, and powder materials. The teeth portion 33 and the yoke portion 34 of the present embodiment are configured to include soft magnetic wire materials 41. At least a part of the plurality of soft magnetic wire materials 41 constituting the stator core 3 is continuous between the teeth portion 33 and the yoke portion 34. The stator core 3 can be configured by bundling a plurality of soft magnetic wire materials 41. By configuring with the soft magnetic wire material 41, the stator core 3 can freely change the shape of the outer contour of the cross section cut along the plane orthogonal to the stretching direction of the soft magnetic wire material 41. Hereinafter, the cross section cut along the plane orthogonal to the stretching direction of the soft magnetic wire material 41 is simply referred to as the "cross section". In the present embodiment, the cross-sectional shapes of the teeth portion 33 and the yoke portion 34 are different.

[0023] There is a need to reduce the thickness of the rotating electrical machine 100. Therefore, in this embodiment, the axial portion of the placement portion 35 is shorter than the other directions. As an example, the axial width J35 of the placement portion 35 where the coil 8 of the yoke portion 34 is arranged is smaller than the width C35 in the direction different from the axial direction and the longitudinal direction of the yoke portion. Note that the longitudinal direction of the yoke portion refers to the stretching direction of the soft magnetic wire 41. Specifically, as shown in FIG. 1, the outer contour S35 of the cross section of the placement portion 35 has an axial width J35 smaller than the width C35. In this case, since the axial width J35 is small, the axial length of the rotating electrical machine 100 can be reduced, which is advantageous for reducing the thickness of the rotating electrical machine 100.

[0024] The portion of the tooth portion 33 facing the magnetic pole 26 is called the facing portion 36. The outer contour S36 of the facing portion 36 is shown in FIG. 1. When the radial width R36 of the facing portion 36 is small, the facing area between the magnet 24 of the facing portion 36 and the magnetic pole 26 becomes small, and the characteristics of the rotating electrical machine 100 deteriorate. Therefore, in this embodiment, the radial width R36 of the facing portion 36 facing the magnetic pole 26 of the tooth portion 33 is larger than the axial width J35 of the placement portion 35. In this case, the facing area between the facing portion 36 and the magnetic pole 26 can be increased. Also, in this example, the circumferential width C36 of the outer contour S36 is larger than the width C35.

[0025] The soft magnetic wire 41 will be described. From the viewpoint of obtaining desired magnetic characteristics, the soft magnetic wire 41 can contain a predetermined additive element in the main component iron (Fe). Examples of this additive element include carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), and the like. The soft magnetic wire 41 in this example contains 0.1 mass% to 6.0 mass% of silicon (Si) in the main component iron (Fe). The type and content rate of the additive element can be set by experiments or simulations according to the desired characteristics.

[0026] The soft magnetic wire 41 can be formed by stretching a material into a wire of a desired thickness through plastic working such as wire drawing. If the outer diameter of the soft magnetic wire 41 (the diameter of the circle circumscribing the outer surface of the cross section) is too large, the eddy current loss increases, and if it is too small, the productivity decreases. From these, the outer diameter of the soft magnetic wire 41 can be set by experiment or simulation so as to obtain desired characteristics. The cross-sectional shape of the soft magnetic wire 41 may be circular, elliptical, polygonal, or the like. The outer surface of the soft magnetic wire 41 may be insulated from the viewpoint of reducing the eddy current loss. The soft magnetic wire 41 is subjected to a predetermined heat treatment after the stretching process in order to reduce the processing strain.

[0027] The operation of the rotating electrical machine 100 configured as described above will be described. When the rotating electrical machine 100 is a motor, three-phase drive currents are supplied to the coils 8-U, 8-V, and 8-W of the coil 8 from a drive circuit (not shown) respectively. Thereby, a rotating magnetic field is generated in the opposing portion 36 of the tooth portion 33, and a rotational torque is generated in the magnet 24 due to the interaction between this rotating magnetic field and the magnetic pole 26 of the magnet 24. Due to this rotational torque, the rotor 2 rotates together with the magnet 24.

[0028] When the rotating electrical machine 100 is a generator, when the rotor 2 rotates, the positional relationship between the magnetic pole 26 and the opposing portion 36 of the tooth portion 33 changes sequentially. As a result, the magnitude of the magnetic flux F supplied from the magnetic pole 26 to each phase of the stator core 3 changes in a sine wave shape, and a three-phase alternating voltage is output from the coils 8-U, 8-V, and 8-W of the coil 8.

[0029] In the description of the present embodiment, an example in which the rotating electrical machine 100 includes one rotor 2 and one stator 4 has been shown, but the present invention is not limited to this. For example, the rotating electrical machine may include a plurality of rotors, the rotating electrical machine may include a plurality of stators, or the rotating electrical machine may include a plurality of rotors and a plurality of stators.

[0030] In the description of this embodiment, an example in which the rotating electrical machine 100 includes three stator cores 3 has been shown, but the present invention is not limited to this. For example, the number of stator cores 3 may be an integral multiple of 3 such as 6, 9, 12, etc. In this case, the number of magnetic poles 26 may be changed according to the number of stator cores 3.

[0031] The features of the rotating electrical machine 100 of this embodiment configured as described above will be described. The rotating electrical machine 100 includes a rotor 2 having a magnet 24 provided with a plurality of magnetic poles 26 and rotatable about a rotation axis, a stator 4 having a stator core 3 facing the magnetic poles 26, and a coil 8 provided in the stator core 3. The stator core 3 has a tooth portion 33 facing the magnetic poles 26 and a yoke portion 34 connecting the tooth portions 33, and the coil 8 is disposed in the yoke portion 34.

[0032] According to this configuration, the cross-sectional area of the tooth portion 33 can be made larger than the case where the coil is disposed around the tooth portion 33 which is a salient pole, so that the facing area between the tooth portion 33 and the magnetic pole 26 can be further increased, and the magnetic flux F supplied from the magnetic pole 26 to the tooth portion 33 increases, which is advantageous from the viewpoint of improving the performance of the rotating electrical machine. As a result, an improvement in the efficiency of the rotating electrical machine 100 can be expected. Further, since the magnetic flux F supplied to the tooth portion 33 increases, it is also possible to use a magnet made of a magnet material having a low maximum energy product as the magnet 24, which is advantageous for cost reduction.

[0033] [Second Embodiment] With reference to FIGS. 3, 4, and 5, the configuration of the rotating electrical machine 100 according to the second embodiment will be described. FIG. 3 is a side view schematically showing the rotating electrical machine 100 of the second embodiment. FIG. 4 is a side view schematically showing another example of the rotating electrical machine 100 of the second embodiment. FIGS. 3 and 4 correspond to FIG. 1. In the description of this embodiment, the same or equivalent components and members as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions are appropriately omitted. In addition, for the same or equivalent components and members as those in the first embodiment and those added in the second embodiment, the name is suffixed with "second" and "-B" is added to the end of the reference numeral.

[0034] The rotating electrical machine 100 of this embodiment further includes a second rotor 2-B and a second stator core 3-B. The coil 8 is shared by the stator core 3 and the second stator core 3-B, which is different from the first embodiment, and other configurations are the same. As shown in FIGS. 3 and 4, the second rotor 2-B is a rotor different from the rotor 2, is disposed on the axially opposite side of the rotor 2 with the stator core 3 interposed therebetween, and has second magnetic poles 26-B. The second rotor 2-B has a configuration in which the rotor 2 is axially inverted. The second stator core 3-B has a configuration in which the stator core 3 is axially inverted and faces the second magnetic poles 26-B.

[0035] As shown in FIGS. 3 and 4, the coil 8 is shared by the stator core 3 and the second stator core 3-B. That is, the coil 8 is wound around a portion where the arrangement portion 35 of the yoke portion 34 of the stator core 3 and the second arrangement portion 35-B of the second yoke portion 34-B of the second stator core 3-B are axially overlapped.

[0036] In the example of FIG. 3, the second arrangement portion 35-B of the second yoke portion 34-B is separate from the arrangement portion 35 of the yoke portion 34. In the example of FIG. 4, the second arrangement portion 35-B is integrally formed with the arrangement portion 35. Specifically, the arrangement portions 35 and 35-B, which are the portions where the respective coils 8 of the stator core 3 and the second stator core 3-B are provided, are integrally formed.

[0037] FIG. 5 is a plan view showing the yoke portion 34 viewed from the axial direction. The yoke portion 34 may interfere with the shaft 12. Therefore, in this embodiment, as shown in FIG. 5, the yoke portion 34 is bent so as to avoid interference with the shaft 12. In this case, interference between the yoke portion 34 and the shaft 12 can be avoided.

[0038] The rotating electrical machine 100 of the second embodiment configured as described above operates in the same manner as the rotating electrical machine 100 of the first embodiment, and exhibits the same operations and effects as the first embodiment.

[0039] The above has described in detail examples of several embodiments of the present invention. Each of the above-described embodiments is merely a specific example for implementing the present invention. The content of the embodiments does not limit the technical scope of the present invention, and many design changes such as changes, additions, deletions, etc. of components are possible without departing from the inventive concept defined in the claims. In the above-described embodiments, regarding the content where such design changes are possible, explanations are given with notations such as "in the embodiment" and "in the embodiment", but design changes may also be permitted for the content without such notations. Also, the hatching in the drawings does not limit the material of the object with hatching.

[0040] (Modification example) Hereinafter, a modification example will be described. In the drawings and explanations of the modification example, the same or equivalent components and members as those in the present embodiment are denoted by the same reference numerals. Explanations overlapping with the present embodiment are appropriately omitted, and the configurations different from the present embodiment will be mainly described.

[0041] In the above description, an example where the rotating electrical machine 100 is an axial-gap type rotating electrical machine is shown, but the present invention is not limited thereto. For example, the rotating electrical machine may be a radial-gap type rotating electrical machine.

[0042] In the above description, an example where the magnet 24 is an annular member surrounding the rotation axis La is shown, but the present invention is not limited thereto. For example, the magnet may be a segment magnet divided for each drive pole. As the shape of the segment magnet, a circular shape, an elliptical shape, a trapezoidal shape, a fan shape, etc. can be adopted.

[0043] In the above description, an example where the magnet 24 is a neodymium magnet is shown, but the present invention is not limited thereto. For example, the magnet may be a rare-earth magnet mainly composed of a rare-earth element different from neodymium, a ferrite magnet, or a plastic magnet.

[0044] In the above description, an example in which the stator support member 32 is made of a non-magnetic material is shown, but the present invention is not limited thereto. For example, the stator support member may include a soft magnetic material such as an electromagnetic steel sheet.

[0045] In the above description, an example in which the bearing means 28 is a rolling bearing is shown, but the present invention is not limited thereto. For example, the bearing means may be a sliding bearing such as an oil-impregnated metal bearing.

[0046] Each of these modifications has the same operations and effects as those of the first embodiment.

[0047] Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. The new embodiment resulting from the combination has the effects of the combined embodiments and modifications.

Explanation of Reference Numerals

[0048] 2 Rotor, 3 Stator core, 4 Stator, 8 Coil, 24 Magnet, 26 Pole, 33 Tooth portion, 34 Yoke portion, 35 Arrangement portion, 36 Opposing portion, 41 Soft magnetic wire, 100 Rotating electrical machine.

Claims

1. A rotor having a magnet provided with a plurality of magnetic poles and rotatable about a rotation axis, A stator having a stator core facing the magnetic poles, A coil provided in the stator core, Comprising: The stator core has a tooth portion facing the magnetic poles and a yoke portion connecting the tooth portions to each other, The coil is disposed in the yoke portion, an electric rotating machine.

2. The arrangement portion in which the coil of the yoke portion is disposed has an axial width smaller than a width in a direction different from the axial direction and the longitudinal direction of the yoke portion. The electric rotating machine according to claim 1.

3. The circumferential width of the opposing portion of the tooth portion facing the magnetic poles is smaller than the circumferential width of the arrangement portion, The radial width of the opposing portion is larger than the axial width of the arrangement portion. The electric rotating machine according to claim 2.

4. The tooth portion and the yoke portion are configured to include a soft magnetic wire. The electric rotating machine according to claim 1.

5. A second rotor different from the rotor, disposed on the axially opposite side of the rotor with the stator core interposed therebetween and having a second magnetic pole, and a second stator core facing the second magnetic pole, The coil is shared by the stator core and the second stator core. The electric rotating machine according to claim 1.

6. The portions in which the coils of the stator core and the second stator core are provided are integrally configured. The electric rotating machine according to claim 5.

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