DE102016219829B4 - Rotating electrical machine - Google Patents

Abstract

A rotating electrical machine (1) having a central longitudinal axis (1C), comprising: a stator (100); and a rotor (200) configured to be rotatable about the central longitudinal axis (1C) when magnetic flux emanating from the stator (100) flows through the rotor (200), the stator (100) comprising:a stator core (110), having a plurality of stator teeth (130) circumferentially and evenly distributed about the central longitudinal axis (1C); and a plurality of armature coils (140), each toroidally wound around the stator core (110) between two adjacent stator teeth (130), and wherein the rotor (200) comprises: a rotor core (210) having a plurality of rotor teeth (230) distributed circumferentially about the central longitudinal axis, each of the rotor teeth being a set of a first rotor tooth (231), a second rotor tooth (232) and a third rotor tooth (233) aligned axially such that the first rotor tooth (231) is arranged to sequentially face an axial end surface of each of the stator teeth (130), so that the second rotor tooth (232) is arranged to sequentially face a radially inner circumferential surface of each of the stator teeth (230), and such that the third rotor tooth (233) is arranged to sequentially face a radially outer peripheral surface of each of the stator teeth (130); characterized in that the rotor (200) further comprises: a plurality of induction coils (I), each wound around one of the plurality of rotor teeth (230) are wound; anda plurality of exciting coils (F), each wound around one of said plurality of rotor teeth (230); wherein each of the induction coils (I) and the associated one of the field coils (F) are layered on the same one of the rotor teeth (230), and the induction coils (I) are less separated from the stator (100) than the field coils (F). ; andcoupling of magnetic fluxes emanating from the plurality of armature coils (140) with the plurality of induction coils (I) causes the plurality of induction coils (I) to generate induction currents that function as electromagnets for the rotor (200). generate when the induction currents flow in the plurality of excitation coils (F).

Description

[technical subject]

The present invention relates to a rotary electric machine having a plurality of torque-generating surfaces of a rotor relative to a stator.

[Prior Art]

JP 2010-226808A (referred to as Patent Literature 1) discloses a rotary electric machine including three torque-generating surfaces of a rotor relative to a stator. The known rotary electric machine comprises an annular stator comprising a stator core and armature windings toroidally wound around the stator core, a radial rotor spaced radially inwardly from and opposed to the stator, and two axial rotors, one of which axially spaced from and facing one side of the stator and the other of which is axially spaced from and facing the other side of the stator.

In this known rotary electric machine, a plurality of permanent magnets are circumferentially distributed around a rotation axis on each of the radial rotor and the two axial rotors. A rotating magnetic field emanating from the stator and directed to the rotors interacts with the field magnetic flux of the permanent magnets, creating a torque that is applied to the rotors.

document JP 2010-246367 A refers to a rotary electric machine that includes a stator core and a rotor. The rotor has a disk-like portion and two cylindrical portions extending from one side of the disk-like portion, one of the cylindrical portions being disposed inside the other cylindrical portion to form an annular space in which the stator core is disposed. Permanent magnets are arranged on inner surfaces of the annular space.

document GB 2 408 154A refers to a stator/rotor assembly for an axial flux, three-phase machine. The three-phase machine has stationary windings which are arranged on a stationary backplate. Adjacent to the stationary windings are three-phase windings on a rotor disk. Current flowing in the stationary windings induces current flow in the three-phase windings. The output of the three-phase windings is rectified in a rectifier and the rectified current is supplied to rotor windings arranged on the rotor disc on a side of the rotor disc remote from the stationary windings and facing a stator core.

[State of the art]

[patent literature]

Patent Literature 1: JP 2010-226808A

[Summary of the Invention]

[Technical problem]

However, the well-known rotary electric machine used in JP 2010-226808A describes permanent magnets to establish magnetic polarities on the radial rotor and the axial rotors. This may cause an increase in material cost and make raw material supply unstable if rare earth magnets, which lie underground in a small amount and are unevenly distributed, are used as the permanent magnets on the radial and axial rotors.

It is an object of the present invention to provide a rotary electric machine configured to improve torque density by increasing torque-generating areas without causing an increase in material cost and without making raw material supply unstable.

[The solution of the problem]

According to one aspect, a rotating electrical machine having a central longitudinal axis is provided. The rotary electric machine includes: a stator; and a rotor configured to be rotatable about the central longitudinal axis when magnetic flux emanating from the stator flows through the rotor, the stator comprising: a stator core having a plurality of stator teeth circumferentially and evenly distributed about the central longitudinal axis are; and a plurality of armature coils, each of which is toroidally wound around the stator core between two adjacent stator teeth, and wherein the rotor comprises: a rotor core having a plurality of rotor teeth distributed circumferentially about the central longitudinal axis, each of the rotor teeth a is a set of a first rotor tooth, a second rotor tooth and a third rotor tooth which are axially aligned so that the first rotor tooth is arranged to sequentially oppose an axial end surface of each of the stator teeth so that the second rotor tooth is arranged, to sequentially face a radially inner peripheral surface of each of the stator teeth and such that the third rotor tooth is arranged to sequentially face a radially outer peripheral surface of each of the stator teeth; a plurality of induction coils each wound around one of the plurality of rotor teeth; and a plurality of exciting coils each wound around one of the plurality of rotor teeth.

[Advantageous Effect of the Invention]

Accordingly, there is provided a rotary electric machine configured to improve torque density by increasing torque-generating areas without causing an increase in material cost and without making raw material supply unstable.

character list

• 1 14 is a perspective view of a rotary electric machine according to an embodiment.
• 2 13 is a cross-sectional view cut by a rotation axis of the rotary electric machine shown in FIG 1 is shown.
• 3 is a perspective view of FIG 1 1, shown, with a portion of a rotor removed.
• 4 14 is a perspective view of the stator with armature coils wound around a stator core.
• 5 is a perspective view of FIG 4 shown stator core without armature coils.
• 6 12 is a perspective view of an armature coil.
• 7 illustrates top views of the in 4 shown stator with armature coils that generate a magnetic flux represented by arrows.
• 8th FIG. 14 is a perspective view of a rotor of FIG 1 shown rotating electric machine.
• 9 FIG. 14 is a perspective view, partially in section, of a rotor core of FIG 8th shown rotor.

[Description of Embodiments]

Referring to the accompanying drawings, the present invention will be described in detail below. The 1 until 9 show a rotating electric machine according to an embodiment.

(configuration of rotating electric machine)

Referring to the 1 , 2 and 3 For example, the rotary electric machine 1 includes a stator 100 and a rotor 200. The stator 100 is configured to generate magnetic flux when coils are energized, and the rotor 200 is about a rotation axis (or a central longitudinal axis) 1C in response to the flow of the magnetic flux rotatable through this. The stator 100 is disposed radially inward (relative to the central longitudinal axis 1C) of the rotor 200 .

Furthermore, the rotating electrical machine 1 comprises a shaft 20 which lies on the central longitudinal axis 1C and extends with a length along this. It is pointed out that the central longitudinal axis 1C is the axis of rotation of the rotor 200 . The shaft 20 is fixed to the inner peripheral edge of the rotor 200 for unitary rotation about the central longitudinal axis 1C.

The rotary electric machine 1 includes an unillustrated case covering the stator 100 and the rotor 200 . This case holds the stator 100 in a stationary manner from the other or upper side of the rotary electric machine 1 as viewed in FIGS 1 , 2 and 3 . When viewing the 1 , 2 , 3 , 4 , 5 , 8th and 9 one side of the rotary electric machine 1 or the stator 100 or the rotor 200 is the bottom thereof, whereas the other side is the top thereof.

The rotary electric machine 1 is configured to cause the induction coils I around the rotor 200 to generate induction current upon receiving a rotating magnetic field generated by armature coils 140 around the stator 100 when the armature coils 140 are excited. Further, the rotary electric machine 1 generates torque by passing this induction current as exciting current through exciting coils F to cause the rotor 200 to operate as electromagnets. From the above description, it can be understood that the rotary electric machine 1 is configured as a self-exciting type excitation-winding synchronous motor without permanent magnets.

(Stator)

Referring to the 1 , 2 , 3 , 4 and 5 The stator 100 includes a stator core 110 and armature coils 140 wound around the stator core 110 are wound. The stator core 110 is made of high permeability magnetic material and is an annular ring structure whose axis is the central longitudinal axis 1C.

The stator core 110 includes a core base or stator yoke 120 and a plurality of stator teeth 130 on the stator yoke 120. The stator yoke 120 is a toroid whose axis of rotation is the central longitudinal axis 1C. The plurality of stator teeth 130 are circumferentially distributed at regular intervals around the central longitudinal axis 1C. The cross section of the stator yoke 120 is a circle or an ellipse.

Each of the stator teeth 130 extends outwardly from the face of the stator yoke 120 . In the view of the stator core 110 of the rotary electric machine 1 along the central longitudinal axis 1C, the stator tooth 130 is a trapezoid. When the stator core 110 of the rotary electric machine 1 is viewed in a circumferential direction, the cross-sectional profile of the stator teeth 130 is a rectangle. The number of the plurality of stator teeth 130 is twelve. Therefore, the twelve stator teeth 130 on the stator yoke 120 are distributed circumferentially and evenly about the central longitudinal axis 1C.

More specifically, each of the stator teeth 130 has a first stator tooth 131, a second stator tooth 132, and a third stator tooth 133.

The first stator tooth 131 extends outwardly from one side of the stator yoke 120 in one or a downward direction along the central longitudinal axis 1C.

The second stator tooth 132 extends radially inward (relative to the central longitudinal axis 1C) from the inner peripheral surface side of the stator yoke 120 .

The third stator tooth 133 extends radially outward from the outer peripheral surface side of the stator yoke 120 .

In the present embodiment, the stator core 110 is a unit (one piece) of an annular structure that cannot be divided into segments. This improves the structural strength of the stator core 110 compared to the case where the stator core 110 is a structure that can be divided into segments. Furthermore, the improved structural strength of the stator core 110 provides increased resistance to excited vibrations.

Each of the armature coils 140 is toroidally wound around the stator yoke 120 using a space between two adjacent ones of the stator teeth 130 of the stator core 110 as a slot. A toroidal winding is a method of winding a wire around a toroid over alternately the radially inside and outside of the stator yoke 120.

Using the toroidal winding structure of the armature coils 140 in the stator yoke 120 makes it possible to form the stator core 110 as an integral structure including the stator yoke 120 to increase the structural strength of the stator core 110 .

The armature coils 140 each located in spaces between one of the stator teeth 130 and the circumferentially adjacent stator teeth 130 are separable into three groups for U-phase, V-phase and W-phase of a three-phase alternating current.

The winding direction and the energizing direction of the armature coils 140 is set such that the magnetic flux emanating from one of a pair of armature coils 140 located directly across one of the stator teeth 130 and the magnetic flux emanating from the other of the pair are circumferentially oriented in opposite directions.

This allows the pair of armature coils 140, for example, one for U+ phase and the other for U- phase, to generate magnetic fluxes directed toward the stator tooth 130 disposed between the pair of armature coils 140.

Referring to 6 For example, the wire 141 for the armature coils 140 is a rectangular flat conductor wire whose cross section is in the shape of a rectangle. Each of the armature coils 140 results from winding the wire or square wire 141 toroidally around the stator yoke 120 of the edgewise wound stator core 110 . Edgewise winding is the process of starting the winding by fixing the wire 141 to the stator yoke 120 with its short edges oriented radially (relative to the central longitudinal axis 1C of the rotary electric machine 1).

With respect to its long edge, the portions of the wire 141 successively abutting at positions aligned in the winding pitch direction are in face-to-face contact with each other. Therefore, the number of turns of each of the armature coils 140 can be increased within a limited space while ensuring a cross section wide enough for the amount of current flowing through the armature coil 140, thereby improving the winding space factor. and this leads to an increase in the magnetomotive force of the stator 100.

Because the portions of the wire 141 which successively abut each other at positions aligned in the winding pitch direction are in face-to-face contact with each other at their long edge as described above, heat is transmitted from one portion to the adjacent portion of the wire 141 managed a large area. This causes an increase in the effective area through which heat is conducted, thereby increasing radiation efficiency.

Both end portions 141A and 141B of the wire 141, which serve as a winding start and as a winding end, can be extended axially (relative to the central longitudinal axis 1C) upwards from the stator 100 and placed within the same plane, thereby connecting the armature coils 140 is simplified.

(Magnetic flux distribution of the stator)

7 12 is a simulation result of electromagnetic field analysis showing the magnetic flux distribution of the stator 100. FIG. For ease of illustration, the stator core 110 and the rotor 200 are illustrated in a linear fashion. Furthermore, in 7 no distinction is made between the first tooth 131, the second tooth 132 and the third tooth 113, and these are represented by the stator teeth 130. The simulation result is obtained by executing the electromagnetic field analysis with the settings that the V-phase current magnitude is 1, the U-phase current magnitude is -0.5, and the W-phase current magnitude is -0.5.

Referring to 7 describes a pair of armature coils 140, one for the V+ phase and the other for the V- phase, disposed directly across a stator tooth 130, wherein the magnetic flux flowing from one armature coil 140 of the pair means and the magnetic flux flowing out from the other armature coil 140 of the pair is directed to the stator tooth 130 located between the pair so that the magnetic fluxes meet within the stator tooth 130 . Each of the magnetic fluxes entering the stator teeth 130 is directed to the direction orthogonal to the stator yoke 120 and guided to the rotor 200 .

Part of the magnetic flux led to the rotor 200 is led to the one circumferentially adjacent stator tooth 130 sandwiched between another pair of armature coils 140, one for W+ phase and the other for W- phase after flowing through a rotor core 210 of the rotor 200 described later. The remaining part of the magnetic flux led to the rotor 200 is led to the other circumferentially adjacent stator tooth 230 sandwiched between another another pair of armature coils, one for the U+ phase and the other for the U- phase , is arranged after flowing through the rotor core 21 of the rotor 200 .

On a face where the stator teeth 130 and the rotor 200 face each other, a magnetic circuit through which the magnetic flux flowing out from the pair of armature coils 140 flows is formed. In the rotary electric machine 1, the surface where the stator teeth 130 and the rotor 200 face each other is a torque-generating surface.

For this reason, the more torque-generating areas there are, the higher the torque density becomes by using the magnetic fluxes generated by a pair of armature coils 140 . Torque density means the magnitude of torque per volume.

Therefore, torque density is increased by having three (3) torque-producing surfaces, i.e., a first surface facing inward from an axial (relative to the central longitudinal axis 1C) end of the rotor 200, a second surface facing in from a radial (relative facing inward to the central longitudinal axis 1C) inner circumference of the rotor 200, and a third surface facing inward from a radially outer circumference of the rotor 200. Because it is small in size but can generate high torque by increasing the number of torque-generating surfaces, the rotary electric machine 1 is excellent as a rotary electric machine for vehicles, particularly hybrid electric vehicles or the like.

(Rotor)

Referring to the 1 , 2 , 3 , 8th and 9 the rotor 200 comprises the rotor core 210, induction coils I and excitation coils F.

How best 9 As can be seen, the rotor core 210 comprises an annular disk portion 211 lying in an imaginary plane orthogonal to the central longitudinal axis 1C, an inner cylindrical portion 212 continuously extending from an inner periphery of the disk portion 211 in a direction along the central longitudinal axis 1C, and an outer Cylinder portion 213 continuously extending from an outer periphery of disc portion 211 in a direction along central longitudinal axis 1C. The disc part 211, the inner cylinder part 212 and the cylinder part 213 are connected to to define an annular groove about the central longitudinal axis 1C that opens in the direction along the central longitudinal axis 1C to receive the stator 100. This annular groove opens in the direction along the central longitudinal axis 1C to make assembly of the rotor 200 and the stator 100 easy. In the present embodiment, the disk portion 211 covers one of two axial ends of the stator core 110, the inner cylinder portion 212 covers the radially inner periphery of the stator core 110, and the outer cylinder portion 213 covers the radially outer periphery of the stator core 110. The rotor core 210 is made of a magnetic Material made with high magnetic permeability.

As described, the rotor core 210 is formed in a cylindrical shape as a whole so that the rotor core 210 covers and faces the axial lower end, the radially inner periphery, and the radially outer periphery of the stator 100 .

In other words, the rotor core 210 is formed in a cylindrical shape having a channel-shaped cross section with three sides thereof being defined by the annular disk part 211, the inner cylinder part 212 and the outer cylinder part 213, so that the rotor core 210 has the stator core 110 of one end toward the other end in a direction along the central longitudinal axis 1C.

Furthermore, the rotor core 210 comprises a multiplicity of rotor teeth 230 which are distributed in the circumferential direction and evenly around the central longitudinal axis 1C. Each of the rotor teeth 230 is a set of axially aligned rotor teeth, namely a first rotor tooth 231, a second rotor tooth 232 and a third rotor tooth 233.

Each of the first, second, and third rotor teeth 231, 232, and 233 of a set forms a torque-producing surface with one of the circumferentially aligned first, second, and third stator teeth 131, 132, and 133 of the stator 100 when the stator 100 is in contact with the circumferentially aligned stator teeth 131 or 132 or 133 in succession.

How from the 3 , 4 and 9 As can be seen, the first rotor teeth 231 are arranged on the disk part 211 and distributed in the circumferential direction about the central longitudinal axis 1C. The first rotor teeth 231 extend axially inward (relative to the central longitudinal axis 1C) from the disk portion 211 to the stator core 110 to face the first stator teeth 131, but are axially separated from the first stator teeth 131 by a predetermined air gap.

The second rotor teeth 232 are disposed on the inner cylinder portion 212 and distributed circumferentially about the central longitudinal axis 1C. The second rotor teeth 232 extend radially outward (relative to the central longitudinal axis 1C) from the inner cylinder portion 212 toward the stator core 110 to confront the second stator teeth 132, but are radially separated from the second stator teeth 132 by a predetermined air gap.

The third rotor teeth 233 are arranged on the outer cylinder part 213 and distributed circumferentially around the central longitudinal axis 1C. The third rotor teeth 233 extend radially inward (relative to the central longitudinal axis 1C) from the outer cylinder portion 213 toward the stator core 110 to face the third stator teeth 133, but are radially separated from the third stator teeth 133 by a predetermined air gap.

The radially (relative to the central longitudinal axis 1C) inner end of one of the first rotor teeth 231 of each set is continuously connected to an axial end of the second rotor tooth 232 of the same set. Furthermore, the radially outer end of one of the first rotor teeth 231 of the same set is continuously connected to an axial end of the third rotor tooth 233 of the same set.

As described, in the rotor core 210, the first, second and third rotor teeth 231, 232 and 233 of each set form a continuous integral structure. In other words, the first, second, and third rotor teeth 231 , 232 , and 233 of each set are integrated to form one of the rotor teeth 230 . The rotor core 210 includes a plurality of rotor teeth 230 circumferentially and evenly distributed.

As best in 2 1, rotating electrical machine 1 includes snap rings 4A and 4B. The rotor core 210 is secured to the shaft 20 by attaching or threading the snap rings 4A and 4B to the shaft 20 so that the snap rings 4A and 4B sandwich the rotor core 210 axially.

The inner periphery of the inner cylinder portion 212 of the rotor core 210 and the outer periphery of the shaft 20 are formed with splines, not shown, respectively. The rotor core 210 is held from relative rotation to the shaft 20 for integral rotation by inserting a key into the keyways.

(induction coils, excitation coils)

The wire Iw for induction coils I and the wire Fw for exciting coils F are each a rectangular flat wire made of copper wire with a rectangular cross section, which is covered with an insulating material. Each of the induction coils I is formed with an alpha winding of wire Iw, while each of the excitation coils F is formed with an alpha winding of wire Fw. Alpha winding is a process of winding the wire Iw or Fw with a winding start and a winding end brought out in the same outward direction.

That end of each of the wires Iw and Fw, which is a winding start, is not left inside in the case of the alpha-wound inductor and exciter coils I and F, thereby improving the winding space factor. The both end portions of each of the wires Iw and Fw are led out from the induction and excitation coils I and F in the same outward direction, thereby facilitating the connection of the coils.

In the present embodiment, the wire Iw of the induction coil I is wound in two columns in a winding pitch direction of the winding, with one end portion of the wire Iw being laid in the first of the two columns and the other end portion of the wire Iw being laid in the second of the two columns, around to lie within the rotor 200 in the same plane.

Further, the wire Fw of the exciting coil F is wound in two columns in a winding pitch direction of winding, with one end portion of the wire Fw laid in the first of the two columns and the other end portion of the wire Fw laid in the second of the two columns to lay in the same To lie within the rotor 200 level.

As described, the end portions of each of the wires Iw and Fw of the alpha-wound inductor and excitation coils I and F can be laid and arranged on the same plane extending parallel to one of the two axial ends (an upper axial end in the present embodiment ) of rotor 200 extends near its inner and outer peripheries, thereby facilitating same-plane connections by using a connector (not shown), such as a connection substrate or the like, located at (or over) the axial end of rotor 200 is. This contributes to a reduction in the axial length of the rotary electric machine 1 .

In addition, if the rotor core 210 covers one axial end and both the radially inner and outer peripheries of the stator 100, the end portions of each of the wires Iw and Fw of the alpha-wound inductor and exciter coils I and F can be laid on the same plane and arranged parallel to the other axial end (a lower axial end in the present embodiment) of the rotor 200 near its inner and outer peripheries, thereby facilitating connections on the same plane by using a connector (not shown). , such as a connection substrate or the like, which is arranged at (or over) the axial end of the rotor 200. FIG. This contributes to a reduction in the axial length of the rotary electric machine 1 .

The radiating performance of the rotor 200 is improved because the wire Iw and the wire Fw have the same thermal conductivity when the induction and excitation coils I and F are wound with alpha winding.

Winding fill factor is improved and copper loss reduced because the inductor and exciter coils I and F are alpha wound.

Furthermore, the induction and excitation coils I and F are wound such that the short edges of the rectangular cross-sections of the wires Iw and Fw are orthogonal to the flux lines of the generated magnetic field.

This reduces the eddy current loss caused in the induction and excitation coils I and F.

Each of the induction and excitation coils I and F is formed such that a radial portion resulting from bending of the alpha winding Iw or Fw has a rectangular shape with its radially inner edge removed.

Specifically, the exciting coils F are bent along the surface inside the rotor core 210 so that each of the exciting coils F surrounds one of the rotor teeth 230 to go around the base portion of the rotor tooth 230 .

On the other hand, the induction coils I are bent along the surface inside the rotor core 210 such that each of the induction coils I surrounds one of the rotor teeth 230 to go around the leading edge portion of the rotor tooth 230 .

As described, each of the induction coils I and the associated one of the armature coils F is disposed on the same one of the rotor teeth 230 in multiple layers, with the induction coil I and armature coil F on a leading edge Section and a base portion of the rotor tooth 230 are arranged so that the induction coils I are less separated from the stator 100 than the excitation coils F. The winding space factor of the induction and excitation coils I and F is improved because each of the induction coils I and one of the excitation coils F are closely located.

Furthermore, the stator core 110 can be installed by axially inserting the stator core into the rotor core 210 without dividing it into stator segments because the rotor core 210 having the channel-shaped cross section is open in the direction along the central longitudinal axis 1C or upward. This improves the assembling throughput of the stator core 110. Further, this improves the cooling performance by efficiently performing heat radiation from the opened side because the rotor core 210 is opened upward.

When the armature coils 140 generate a rotating magnetic field, the magnetic flux emanating from the stator 100 couples with the induction coil I, thereby causing the induction coil I to generate induction current.

(rectifier circuit)

The rotor 200 has diodes as rectifier elements, not shown. The diodes, inductors I and exciting coils F are connected to form rectifier circuits. In the rectifying circuits, AC induction current generated by each of the induction coils I is rectified by the diodes, and the rectified DC current is supplied to the exciting coils F as exciting current. The exciting coils F generate magnetic fields when the rectified direct current is supplied as exciting current to excite the exciting coils F .

(excitation energy)

The rotary electric machine 1 includes twelve (12) stator teeth and eight (8) rotor teeth 230. Therefore, the composition ratio S/P between the number of slots S of the stator 100 and the number of magnetic poles P becomes 3/2 because S=12 and P=8 in the rotary electric machine 1.

In the illustrated rotary electric machine 1, the toroidal-wound concentrated-winding armature coils 140 are installed, and so the second space harmonic in space in the quiescent reference frame is superimposed on the flux of the fundamental frequency as leakage flux, up to about 50%.

Therefore, the third time harmonic in time in the rotating frame enters the rotor 200 because the composition ratio S/P is 3/2. The third time harmonic in the rotating frame of reference has an asynchronous frequency relative to the rotor 200 speed.

In order to effectively use the third time harmonic, the inductors I are wound around the rotor teeth 230, which are salient poles of the rotor 200. FIG. This causes each of the induction coils I to generate induction current when the third time harmonic couples to the induction coils I, and this causes the exciting coils F to generate magnetic fields by using the direct current given by the rectification of the induction current as the exciting current, thereby enabling that the rotor 200 acts as electromagnets.

A high-order time harmonic such as the fourth or fifth time harmonic is nothing more than a wave vibrating only in the vicinity of the surface of the rotor core 210, and so the induction coils I cannot efficiently generate induction current. A low-order space harmonic such as the third time harmonic enters the interior of the rotor core 210 because it is a relatively low-frequency magnetic flux.

In the present embodiment, within the space harmonics superimposed on the magnetic flux of the fundamental frequency, the third time harmonic is restored. This third time harmonic has a higher frequency than the fundamental frequency or the frequency of the second time harmonic and pulsates with a short period.

This efficiently recovers the energy loss caused by space harmonic components and causes the magnitude of the induction current to increase by increasing the temporal variation of the magnetic flux coupling to the induction coils I, thereby providing an increase in torque.

The effects of the rotary electric machine 1 according to the embodiments will be described. In the rotary electric machine 1, the stator 100 includes the stator core 110 having the stator teeth 130 distributed circumferentially and uniformly, and the toroidally wound armature coils 140 each of which is between two adjacent ones of the stator teeth 130 of the stator core 110.

Furthermore, the rotor 200 includes the rotor core 210. The rotor core 210 includes a plurality of rotor teeth 230 in the circumferential direction are distributed about the central longitudinal axis 1C, each of the rotor teeth 230 being a set of the first rotor tooth 231, the second rotor tooth 232 and the third rotor tooth 233 which are axially aligned. The first rotor tooth 231 arranged on the disk part 211 faces the first stator teeth 131 sequentially. The second rotor tooth 232 disposed on the inner cylinder portion 212 faces the second stator teeth 132 sequentially. The third rotor tooth 233 arranged on the outer cylinder part 213 faces the third stator teeth 133 sequentially.

The rotor 200 further includes the induction coils I and the excitation coils F wound around the rotor teeth 230 . The induction coils I are arranged such that each of the induction coils I generates induction current when magnetic flux emanating from the stator 100 couples to the induction coil I . The exciting coils F are arranged such that the exciting coils F generate magnetic field(s) when excited in response to the generation of induction currents.

According to the embodiments, each of the induction coils I is caused to generate induction current when the magnetic flux emanating from the stator 100 couples to the induction coils I, and the exciting coils F are capable of generating magnetic fields by applying a direct current generated by the rectification of the induction current is given, use as excitation current. Therefore, the rotor 200 is able to function as electromagnets, thereby causing torque to be generated to drive the rotor 200 .

Therefore, the increase in material cost and the unstable supply of raw materials resulting from the use of rare earth magnets as permanent magnets are now avoided because torque for driving the rotor 200 is generated without such permanent magnets. Accordingly, there is provided a rotary electric machine 1 configured to generate torque without causing an increase in material cost and without making raw material supply unstable.

Furthermore, according to the embodiments, the torque-generating areas are increased and the torque density is improved because the magnetic flux generated by the stator 100 couples with the rotor teeth 230 inward of the three surfaces, i.e. the first, second and third rotor teeth 231, 232 and 233.

As a result, it is possible to improve torque density by enlarging torque generating areas without causing an increase in material cost and without making raw material supply unstable.

Furthermore, according to the embodiments, within the space harmonics superimposed on the magnetic flux of the fundamental frequency, the third time harmonic is recovered. This allows the harmonics generated at the stator 100 to couple effectively to the rotor teeth 230, thereby providing more magnetic energy.

In addition, in the present embodiment, the stator core 110 can be installed by axially inserting the stator core into the rotor core 210 without dividing it into stator segments because the rotor core 210 having the channel-shaped cross section in the direction along the central longitudinal axis 1C or open upward is. This improves the assembling throughput of the stator core 110. Further, this improves the cooling performance by efficiently performing heat radiation from the opened side because the rotor core 210 is opened upward.

As described, in the present embodiment, the end portions of each of the wires Iw and Fw of the induction and excitation coils I and F are arranged on the same plane extending parallel to one of the two axial ends (an upper axial end) of the rotor 200, where Connections at the same level can be made using a connector located at (or above) the axial end of the rotor 200. This contributes to a reduction in the axial length of the rotary electric machine 1 .

Furthermore, in the rotary electric machine 1 according to the embodiments, each of the induction coils I and the associated one of the armature coils F are arranged on the same one of the rotor teeth 230 in multiple layers. This results in an arrangement in which the induction coils I are less separated from the stator 100 than the excitation coils F.

According to the embodiments, because the inductors I are less separated from the stator 100 than the excitation coils F, the inductors I are caused to generate a large current by allowing more harmonics to couple to the inductors I. The winding space factor is improved because each of the induction coils I and one of the excitation coils F are wound around the same one of the rotor teeth 230 in multiple layers so that they are closely located.

Further, in the present embodiment, the rotor core 210 is an integrated structure in which each of the first rotor teeth 231 sequentially facing the first stator teeth 131, one of the second rotor teeth 232 sequentially facing the second stator teeth 132, and one of the third rotor teeth 233 , which sequentially faces the third stator teeth 133, are continuously connected.

In the rotary electric machine 1 according to the embodiments, the rotor core 210 is cylindrical and covers the stator 100 using its one axial end side and its two radially spaced inner and outer sides.

The wire for the armature coils 140, the induction coils I and the exciting coils F is not limited to a copper wire, and the wire may be an aluminum conductor or a stranded wire of stranded wire for high-frequency power.

In addition, a rotary electric machine 1 can be modified as a hybrid excitation type (or a hybrid type) such that permanent magnets are arranged on a rotor in addition to exciting coils I. In this case, the exciting coils F serving as electromagnets are designed to effectively cooperate with the permanent magnets to generate torque. A substantially equivalent power output can be obtained without an increase in size while suppressing the amount of use of rare earth magnets that causes an increase in material cost.

Furthermore, the rectifying elements are not limited to diodes. Semiconductor elements, like other switching elements, can be used. The rectifying elements are not limited to the type where they are stored in diode cases or holders, but they can be mounted inside the rotor 200.

In addition, the rotary electric machine 1 can be used not only in hybrid electric vehicles but also in wind power generation and machine tools.

Although embodiments of the present invention have been described, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the present invention. All such modifications and their equivalents are intended to be covered by the following claims, which are described within the scope of the claims.

Reference List

1

rotating electric machine

100

stator

110

stator core

130

stator teeth

140

armature coil

200

rotor

210

rotor core

230

rotor teeth

231

first rotor teeth

232

second rotor teeth

233

third rotor teeth

f

excitation coil

I

induction coil.

Claims (3)

A rotating electrical machine (1) having a central longitudinal axis (1C), comprising: a stator (100); and a rotor (200) configured to be rotatable about the central longitudinal axis (1C) when magnetic flux emanating from the stator (100) flows through the rotor (200), the stator (100) comprising: a stator core (110 ) having a plurality of stator teeth (130) circumferentially and evenly distributed about the central longitudinal axis (1C); and a plurality of armature coils (140), each toroidally wound around the stator core (110) between two adjacent stator teeth (130), and wherein the rotor (200) comprises: a rotor core (210) having a plurality of rotor teeth ( 230) distributed circumferentially about the central longitudinal axis, each of the rotor teeth being a set of a first rotor tooth (231), a second rotor tooth (232) and a third rotor tooth (233) aligned axially such that the first rotor tooth (231) is arranged to sequentially face an axial end surface of each of the stator teeth (130), so that the second rotor tooth (232) is arranged to sequentially face a radially inner circumferential surface of each of the stator teeth (230), and so in that the third rotor tooth (233) is arranged to sequentially face a radially outer peripheral surface of each of the stator teeth (130); characterized in that the rotor (200) further comprises: a plurality of induction coils (I) one of which each wrapped around one of the plurality of rotor teeth (230); and a plurality of exciting coils (F) each wound around one of said plurality of rotor teeth (230); each of the induction coils (I) and the associated one of the field coils (F) being layered on the same one of the rotor teeth (230), and the induction coils (I) being less separated from the stator (100) than the field coils (F) are; and wherein coupling of magnetic fluxes emanating from the plurality of armature coils (140) with the plurality of induction coils (I) causes the plurality of induction coils (I) to generate induction currents that function for the rotor (200) as Generate electromagnets when the induction currents flow in the plurality of exciting coils (F). Rotating electrical machine (1) according to claim 1 wherein the first, second and third rotor teeth (231, 232, 233) of each set are continuously connected to form an integrated structure. Rotating electrical machine (1) according to claim 2 wherein the rotor core (210) is cylindrical and covers an axial end side, a radially inner peripheral side and a radially outer peripheral side of the stator (100).

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