JP6929603B2 - Rotating machine - Google Patents

Description

The present invention relates to a rotating machine such as a generator.

For example, a hybrid vehicle (HV) and an electric vehicle (EV) are equipped with a generator.

As a generator, one provided with a centralized winding stator and a permanent magnet type rotor is known. In the centralized winding stator, the stator core has an annular (cylindrical) stator yoke and a plurality of teeth extending radially inward from the stator yoke, and windings are centrally wound around each tooth. The rotor is arranged inside the centralized winding stator, and has an annular rotor yoke concentric with the stator yoke and a plurality of permanent magnets embedded in the rotor yoke side by side in the circumferential direction. A rotating shaft is inserted through the center of the rotor yoke so that it cannot rotate relative to each other.

When a current flows through the coil, a magnetic flux extending in the radial direction of rotation is generated along the teeth, and this magnetic flux acts on the permanent magnets of the rotor to generate a rotational force in the rotor. Therefore, by controlling the current flowing through the coil according to the rotation position of the rotor, a rotational force is continuously generated in the rotor, and the rotor and the rotation shaft rotate in a certain direction.

When the magnetic flux changes, an eddy current flows through the stator core. If the eddy current is large, the iron loss in the coil becomes large and the efficiency of the generator decreases. Therefore, in order to reduce the eddy current loss (iron loss due to the eddy current), a configuration has been proposed in which a non-conductive portion is provided in the tooth to reduce the eddy current flowing through the tooth (see, for example, Patent Document 1). By providing the conductive portion in the tooth, the magnetic flux extending along the tooth is divided into a plurality of parts, and the total sum of the eddy currents flowing in the tooth for each of the divided magnetic fluxes is not provided in the non-conductive portion. Since the configuration is smaller than the eddy current flowing through the teeth, the eddy current loss can be reduced.

Japanese Unexamined Patent Publication No. 2015-595974

However, in the configuration according to the proposal, the total magnetic flux generated by the current flowing through the coil does not change as compared with the configuration in which the non-conductive portion is not provided, and the total magnetic flux is divided by the cross-sectional area of the teeth. The magnetic flux density obtained is the same. Therefore, even if the eddy current loss can be reduced, the effect of reducing the hysteresis loss (the loss when the magnetic domain of the teeth changes the direction of the magnetic field due to the alternating magnetic field) cannot be expected, and the efficiency of the generator is greatly improved. Can't.

An object of the present invention is to provide a rotating machine capable of effectively reducing iron loss in a centralized winding coil and improving efficiency.

In order to achieve the above object, the rotating machine according to one aspect of the present invention is a rotating machine including a stator and a permanent magnet type rotor, and the stator is an annular yoke surrounding the rotor and from the yoke to the rotor side. A stator core having a plurality of extending teeth and a centralized winding coil wound around the teeth are included in the teeth, and one of the teeth is formed by forming a single hole penetrating in the direction of the rotation axis. A narrow portion extending in the extending direction of the tooth and limiting the magnetic flux by magnetic saturation is provided between each of the side surface and the other side surface and the hole.

According to this configuration, the stator core includes a yoke and a plurality of teeth. The yoke forms an annular shape surrounding the rotor, and each tooth extends from the yoke to the rotor side, that is, to the rotation center side. A slot is formed between each of the adjacent teeth, and the centralized winding coil wound around the tooth is housed in the slot. Further, the teeth are provided with a narrow portion extending in the extending direction of the teeth between one side surface and the other side surface and the holes by forming a single hole penetrating in the direction of the rotation axis. There is.

When a current flows through the concentrated winding coil, a magnetic flux extending in the radial direction of rotation is generated along the teeth. Since the teeth are provided with a narrow portion, magnetic saturation occurs in the narrow portion, and the generation of magnetic flux is limited. Therefore, the magnetic flux density obtained by dividing the magnetic flux by the cross-sectional area of the teeth is reduced as compared with the configuration in which the teeth are not provided with the narrow portion. The iron loss in the concentrated winding coil includes a hysteresis loss and an eddy current loss, and as the magnetic flux density is reduced, the hysteresis loss and the eddy current loss are reduced in proportion to the square of the magnetic flux density. Therefore, the iron loss can be effectively reduced, and the efficiency of the rotating machine can be improved.

The teeth may be straight teeth having a constant width in a direction orthogonal to both the rotation axis direction and the rotation radial direction.

The centralized winding coil is preferably formed by winding a winding around the bobbin, and is preferably wound around the teeth by fitting the bobbin to the teeth.

In this configuration, since it is not necessary to wind the winding directly around the teeth, it is possible to eliminate the need for an empty space for arranging the winding nozzle of the winding machine in the slot. Therefore, as compared with the configuration in which the winding is wound directly on the teeth, the space factor of the coil (winding) in the slot can be increased, and the efficiency of the rotating machine can be further improved.

The centralized winding coil includes a trapezoidal trapezoidal coil that tapers toward the tip of the teeth (as it approaches the rotation axis) when viewed from the direction of the rotation axis, and a rectangular coil that is rectangular when viewed from the direction of the rotation axis. It is preferable that the trapezoidal coil and the rectangular coil are arranged alternately in the circumferential direction of the stator core.

With this configuration, the space factor of the coil in the slot can be further increased, and the efficiency of the rotating machine can be further improved.

The rotating machine according to another aspect of the present invention is a rotating machine including a stator and a permanent magnet type rotor, and the stator has an annular yoke surrounding the rotor and a plurality of teeth extending from the yoke to the rotor side. A stator core and a centrally wound coil wound around the tooth are included, and the tooth has at least one side surface and height of the tooth by forming a magnetically high resistance portion having a magnetic permeability smaller than that of an electromagnetic steel sheet. A narrow portion for limiting the magnetic flux by magnetic saturation is provided between the resistance portion.

According to this configuration, the stator core includes a yoke and a plurality of teeth. The yoke forms an annular shape surrounding the rotor, and each tooth extends from the yoke to the rotor side, that is, to the rotation center side. A slot is formed between each of the adjacent teeth, and the centralized winding coil wound around the tooth is housed in the slot. Further, the teeth are formed with a magnetically high resistance portion having a magnetic permeability smaller than that of the electromagnetic steel plate, and at least a narrow portion is provided between one side surface of the teeth and the hole. The high resistance portion has a smaller magnetic permeability than the electromagnetic steel plate which is the material of the stator core.

When a current flows through the concentrated winding coil, a magnetic flux extending in the radial direction of rotation is generated along the teeth. Since the teeth are provided with a narrow portion, magnetic saturation occurs in the narrow portion, and the generation of magnetic flux is limited. Therefore, the magnetic flux density obtained by dividing the magnetic flux by the cross-sectional area of the teeth is reduced as compared with the configuration in which the teeth are not provided with the narrow portion. The iron loss in the concentrated winding coil includes a hysteresis loss and an eddy current loss, and the hysteresis loss and the eddy current loss are reduced in proportion to the square of the magnetic flux density as the magnetic flux density is reduced. Therefore, the iron loss can be effectively reduced, and the efficiency of the rotating machine can be improved.

According to the present invention, the iron loss in the centralized winding coil can be effectively reduced, and the efficiency of the rotating machine can be improved.

It is sectional drawing of the generator which concerns on one Embodiment of this invention. It is sectional drawing of a part of a stator core. It is a figure which shows the 1st modification of a stator core, and is the figure which was seen from the direction of the rotation axis. It is a figure which shows the 2nd modification of a stator core, and is the figure which was seen from the direction of the rotation axis. It is a figure which shows the 3rd modification of the stator core, and is the figure which was seen from the direction of the rotation axis.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Generator>
FIG. 1 is a cross-sectional view of a motor 1 according to an embodiment of the present invention.

The generator 1 is mounted as a generator in, for example, a hybrid vehicle or an electric vehicle. The generator 1 includes a stator 2 and a rotor 3. The stator 2 and rotor 3 are housed in a case (not shown).

The stator 2 includes a stator core 11 and a centralized winding coil 12. The stator core 11 is made of a laminated steel plate formed by stacking electromagnetic steel plates, and has a stator yoke 13 and a plurality of teeth 14.

The stator yoke 13 has a cylindrical shape having a width in the radial direction of rotation about the rotation axis of the generator 1. In other words, the stator yoke 13 forms an annular shape having a width in the radial direction of rotation about the rotation axis when viewed from the direction of the rotation axis of the generator 1.

The plurality of teeth 14 are provided at equal angular intervals about the rotation axis of the generator 1, that is, the center line of the stator yoke 13, and extend from the inner peripheral surface of the stator yoke 13 toward the center line of the stator yoke 13. ing. Each tooth 14 is a straight tooth having a constant width in a direction orthogonal to both the rotation axis direction and the rotation radial direction. Specifically, each tooth 14 has two side surfaces 14A and 14B extending in the extending direction from the stator yoke 13 and a tip surface 14C connecting the tip edges of the side surfaces 14A and 14B. The side surfaces 14A and 14B extend linearly along the extending direction of the teeth 14 and are parallel to each other. The tip surface 14C is formed in an arc shape concentric with the outer peripheral surface of the stator yoke 13.

Each of the adjacent teeth 14 is formed as a slot 15 for accommodating the centralized winding coil 12. The slot 15 has a bottom surface 15A orthogonal to the side surface 14A of the tooth 14 on one side and a bottom surface 15B orthogonal to the side surface 14B of the tooth 14 on the other side and having the same size as the bottom surface 15A. In slot 15, the side surface 14A on one side and the side surface 14B on the other side are closer to each other as they approach the center line of the stator yoke 13, so that the slot 15 is closer to the center line of the stator yoke 13 so that the circumference of the stator yoke 13 is closer. It has a shape that narrows the width in the direction.

The electromagnetic steel plate constituting the stator core 11 may be formed by connecting a divided body including one tooth 14 and the bottom surfaces 15A and 15B on both sides thereof, or may be integrally formed.

The centralized winding coil 12 is formed by winding a winding 22 around a square frame-shaped bobbin 21. The bobbin 21 is fitted onto the teeth 14 and extends outward from the annular portion 23 in contact with the side surfaces 14A and 14B of the teeth 14 and the outer edge of the annular portion 23 in the radial direction in the rotational direction, and extends on one side of the teeth 14. The outer collar portion 24 in contact with the bottom surface 15A of the slot 15 and the bottom surface 15B of the slot 15 on the other side, and the inner collar portion extending from the inner edge of the annular portion 23 in the radial direction to the periphery and parallel to the outer collar portion 24. It has 25 integrally. The winding 22 is wound around the annular portion 23 of the bobbin 21.

The centralized winding coil 12 includes a trapezoidal coil 26 and a rectangular coil 27 due to the difference in shape. The bobbin 21 of the trapezoidal coil 26 is formed in a shape in which the outer flange portion 24 projects larger than the inner flange portion 25. Then, the windings 22 are wound around the bobbin 21 more than once in the radial direction of rotation, so that the trapezoidal coil 26 composed of the windings 22 has a cross-sectional shape inside in the radial direction of rotation (the rotation axis side of the generator 1). ) It has a trapezoidal shape that becomes thinner. In the bobbin 21 of the rectangular coil 27, the outer flange portion 24 and the inner flange portion 25 are formed in the same shape. Then, the winding 22 is wound around the bobbin 21 with the same overlap at each position in the radial direction of rotation, so that the rectangular coil 27 made of the winding 22 has a rectangular cross section. The number of turns of the trapezoidal coil 26 and the rectangular coil 27 is the same.

The trapezoidal coil 26 and the rectangular coil 27 are alternately arranged in the rotation direction of the generator 1, that is, in the circumferential direction of the stator yoke 13. First, the bobbin 21 of the trapezoidal coil 26 is externally fitted to every other tooth 14, and then the bobbin 21 of the rectangular coil 27 is externally fitted to the remaining teeth 14, so that each tooth 14 has a trapezoidal shape. The coil 26 or the rectangular coil 27 is wound. In this order, the bobbin 21 of the trapezoidal coil 26 and the rectangular coil 27 can be fitted onto the teeth 14, and in the reverse order, when the bobbin 21 of the trapezoidal coil 26 is fitted onto the teeth 14. The bobbin 21 interferes with the rectangular coil 27, and the bobbin 21 of the trapezoidal coil 26 cannot be fitted onto the teeth 14.

The rotor 3 is a permanent magnet type rotor. Specifically, the rotor 3 is arranged inside the stator 2, and has a cylindrical shape having a width in the rotational radial direction about the rotation axis of the generator 1, in other words, when viewed from the rotation axis direction of the generator 1. Further, it has an annular rotor yoke 31 having a width in the rotational radial direction about the rotation axis. A gap is provided between the outer peripheral surface 31A of the rotor yoke 31 and the tip surface 14C of the teeth 14. A plurality of (for example, 16 (8 poles)) permanent magnets 32 are arranged side by side in the circumferential direction on the rotor yoke 31. A rotation shaft 33 is inserted through the center of the rotor yoke 31 so that it cannot rotate relative to each other.

<Narrow part>
FIG. 2 is a cross-sectional view of a part of the stator core 11.

Each tooth 14 of the stator core 11 is formed with a hole 41 penetrating the electromagnetic steel plate in the thickness direction at a position closer to the tip side than the center in the extending direction from the stator yoke 13. The hole 41 has a rectangular shape having a first side 42, a second side 43, a third side 44, and a fourth side 45. The first side 42 extends parallel to one side surface 14A of the teeth 14 at intervals. The second side 43 extends parallel to the other side surface 14B of the teeth 14 with the same distance as the distance between the side surface 14A and the first side 42, and has the same length as the first side 42. The third side 44 extends in a direction orthogonal to the first side 42 and the second side 43, and connects the inner ends of the first side 42 and the second side 43 in the radial direction. The fourth side 45 extends in a direction orthogonal to the first side 42 and the second side 43, and connects the outer ends of the first side 42 and the second side 43 in the radial direction.

Due to the formation of the holes 41, the teeth 14 have narrow portions 46 and 47 between the side surface 14A and the first side 42 and between the side surface 14B and the second side 43, respectively. The narrow portions 46 and 47 have the same length as the first side 42 and the second side 43, and extend in the extending direction of the teeth 14 from the stator yoke 13.

When a current flows through the concentrated winding coil 12, a magnetic flux extending in the radial direction of rotation is generated along the teeth 14. This magnetic flux acts on the permanent magnet 32 of the rotor 3 to generate a rotational force in the rotor 3. Therefore, by controlling the current flowing through the centralized winding coil 12 according to the rotation position of the rotor 3, a rotational force is continuously generated in the rotor 3, and the rotor 3 and the rotating shaft 33 rotate in a certain direction.

The size and position of the holes 41 and the number of turns of the concentrated winding coil 12 are designed so that magnetic saturation occurs in the narrow portions 46 and 47 when a current flows through the concentrated winding coil 12. Magnetic saturation occurs in the narrow portions 46 and 47, limiting the generation of magnetic flux. Therefore, as compared with the configuration in which the teeth 14 are not provided with the narrow portions 46 and 47, the magnetic flux density in the portions other than the narrow portions 46 and 47 of the teeth 14 (= magnetic flux / the portions other than the narrow portions 46 and 47 of the teeth 14). The cross-sectional area when cut in a plane orthogonal to the radial direction of rotation) is reduced.

The iron loss Wi in the concentrated winding coil 12 is a value obtained by adding the hysteresis loss Ph and the eddy current loss Pe. The hysteresis loss Ph can be obtained according to the equation (1), and the eddy current loss Pe can be obtained according to the equation (2).

Ph = Kh ・ Bm ^1.6・ f ・ ・ ・ (1)
Pe = Ke ・ Bm ²・ f ²・ ・ ・ (2)
However, Kh: hysteresis loss coefficient
Ke: Eddy current loss coefficient
Bm: Maximum magnetic flux density
f: frequency

On the other hand, the torque T of the generator 1 can be obtained according to the equation (3).
T = Pn {Φm + (Ld-Lq) ・ Id} ・ Iq ・ ・ ・ (3)
However, Φm: magnet magnetic flux
Pn: pole logarithm
Ld: d-axis inductance
Lq: q-axis inductance
Id: d-axis current
Iq: q-axis current

Since equation (3) is derived from the outer product of the current vector and the armature interlinkage magnetic flux vector, the torque T is proportional to the maximum magnetic flux density Bm. Therefore, as the magnetic flux density decreases, the hysteresis loss Ph and the eddy current loss Pe decrease in proportion to the square of the magnetic flux density, while the torque T decreases in proportion to the first power of the magnetic flux density. Therefore, by providing the narrow portions 46 and 47 in the teeth 14, it is possible to effectively reduce the iron loss Wi in the centralized winding coil 12 while suppressing the decrease in torque T, and to improve the efficiency of the generator 1. Can be done.

<Effect>
As described above, in the generator 1, since the teeth 14 of the stator core 11 are provided with the narrow portions 46 and 47, the iron loss Wi in the centralized winding coil 12 is effectively reduced while suppressing the decrease in torque T. It can be reduced and the efficiency can be improved.

In the configuration in which the holes 41 for providing the narrow portions 46 and 47 are formed in the teeth 14, the decrease in the rigidity of the teeth 14 can be suppressed, and the problem of vibration and abnormal noise due to fluctuations in the magnetic attraction force is unlikely to occur. You can also expect the effect.

Further, the hole 41 can also be used for fixing the bobbin 21 outerly fitted in the tooth 14.

The centralized winding coil 12 is formed by winding the winding 22 around the bobbin 21, and is wound around the teeth 14 by fitting the bobbin 21 to the teeth 14. Since it is not necessary to wind the winding 22 directly around the teeth 14, it is possible to eliminate the need for an empty space for arranging the winding nozzle of the winding machine in the slot 15. Therefore, the space factor of the centrally wound coil 12 in the slot 15 can be increased as compared with the configuration in which the winding 22 is wound directly on the teeth 14, and the efficiency of the generator 1 can be further improved.

The centralized winding coil 12 includes a trapezoidal trapezoidal coil 26 that tapers toward the tip of the teeth 14 (as it approaches the rotation axis) when viewed from the direction of the rotation axis, and a rectangular coil 27 that is rectangular when viewed from the direction of the rotation axis. The trapezoidal coil 26 and the rectangular coil 27 are arranged alternately in the circumferential direction of the stator core 11. As a result, the space factor of the centralized winding coil 12 in the slot 15 can be further increased, and the efficiency of the generator 1 can be further improved.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, the hole 41 formed in the teeth 14 of the stator core 11 is not limited to a rectangular shape, and may have a pentagonal shape as shown in FIG. Specifically, in addition to the first side 42, the second side 43, and the third side 44, the hole 41 is formed on the outer side in the rotational radial direction and on the second side 43 side from the outer end in the rotational radial direction of the first side 42. A fifth side 51 extending from the outer end of the second side 43 in the rotational radial direction to the outer side in the rotational radial direction and the first side 42 side, and connected to the outer end in the rotational radial direction of the fifth side 51. It may have 6 sides 52. By adopting the shape shown in FIG. 3, a large opening area of the hole 41 can be secured, and the weight of the stator core 11 can be reduced.

Further, the hole 41 may have the shape shown in FIG. That is, as shown in FIG. 4, the hole 41 rotates from the inner end in the radial direction of the first side 42 in addition to the first side 42, the second side 43, the fifth side 51, and the sixth side 52. The seventh side 53 extending inward in the radial direction and extending toward the second side 43, and the eighth side 54 extending inward in the radial direction and extending toward the first side 42 from the inner end in the rotational radial direction of the second side 43, and rotating. It may have a shape that is orthogonal to both the axial direction and the radial direction of rotation and has a ninth side 55 that connects the inner ends of the seventh side 53 and the eighth side 54 in the radial direction of rotation.

Further, as shown in FIG. 5, the third side 44 and the fourth side 45 may be formed in an arc shape which is convex outward in the radial direction of rotation, respectively.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Generator (rotating machine)
2: Stator 3: Rotor 11: Stator core 12: Concentrated winding coil 13: Stator yoke 14: Teeth 14A, 14B: Side surface (one side surface, the other side surface)
41: Holes 46, 47: Narrow part

Claims (1)

A rotating machine equipped with a stator and a permanent magnet type rotor.
The stator includes an annular yoke surrounding the rotor, a stator core having a plurality of teeth extending from the yoke to the rotor side, and a centralized winding coil wound around the teeth.
By forming a single hole penetrating in the direction of the rotation axis in the tooth, it extends in the extending direction of the tooth between one side surface and the other side surface of the tooth and the hole, and due to magnetic saturation. There is a narrow part to limit the magnetic flux ,
The hole is a rotating machine in which the end portion on the outer side in the radial direction of rotation is formed in a triangular shape so as to be convex on the outer side in the radial direction of rotation.

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