JP2003274589A - Rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the number of stator flux coupling for increasing the output of a rotating electric machine by adopting such a structure that magnets in the same number as in conventional arts are used and the magnetic field reluctance is reduced, as compared with conventional examples. <P>SOLUTION: A rotating electric machine is of a double-rotor structure and is formed by coaxially placing an inner rotor 2 and an outer rotor 3 inside and outside a stator 1. The stator 1 comprises a plurality of stator pieces 4; brackets 5 which are placed at both ends of a stator in the axial direction and fasten the stator pieces 4 circumferentially disposed with equal intervals; coils 7 wound around the stator pieces 4 so that magnetic fields are produced in the direction of the axis of the stator; and outer magnets 8 and inner magnets 9 comprising magnets 8N and 8S and 9N and 9S in multipolar pairs, different in porality to each other, disposed so that the coils 7 are sandwiched between the outer rotor 3 and the inner rotor 2 in the direction of the axis of the stator. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine having a double rotor structure in which rotors are coaxially arranged on both the inner circumference and the outer circumference of a stator.

[0002]

2. Description of the Related Art As a conventional example of a rotating electric machine having a double rotor structure, there is, for example, one described in Japanese Patent Laid-Open No. 11-275826. In this conventional rotating electric machine, the rotor is arranged on the inner and outer circumferences of the stator, and the stator has a coil wound in the axial direction. Therefore, the magnetic flux in the stator flows in the radial direction.

FIG. 8 shows the flow of the magnetic field of the conventional rotary electric machine.
It will be described based on. FIG. 8 shows the outer rotor magnetic path and the inner rotor magnetic path. The outer rotor magnetic path serves as a path that returns from the outer magnet to the outer magnet through the outer rotor and across the gap between the adjacent inner stators. Similarly, the inner rotor magnetic path is the inner magnet that passes through the inner rotor to the adjacent outer magnet. It is a path that returns to the inner magnet across the gap between the side stators.

[0004]

In the conventional rotary electric machine described above, since the outer rotor magnetic path and the inner rotor magnetic path cross the air gap between adjacent stators, the magnetic field resistance of the magnetic paths becomes large, and There is a problem that the number of flux linkages of the stator is reduced as compared with a rotating electric machine having a structure in which no air gap exists between the stators.

Although only the magnetic path passing through the air gap between adjacent stators is shown in FIG. 8, for example, the outer rotor magnetic flux forming the magnetic path of the outer rotor passes through the inner rotor without passing through the air gap between adjacent stators. Even in such a case, the outer rotor magnetic flux passes through the inner rotor magnet from the outer magnet through the gap between the stator and the inner rotor, and the magnetic field resistance increases.

The present invention has been made in order to solve the above-mentioned problems, and by using the same number of magnets as in the above-mentioned prior art and reducing the magnetic field resistance more than in the above-mentioned conventional example, the stator linkage is improved. The purpose is to increase the number of magnetic fluxes to increase the output.

[0007]

In order to achieve the above object, a first invention according to a first aspect of the present invention is a double rotor structure in which rotors are coaxially arranged on both the inner circumference and the outer circumference of a stator. In a rotating electric machine, the stator includes a plurality of stator pieces, brackets that are respectively installed at both ends in the axial direction of the stator, and that fix the stator pieces that are circumferentially arranged at equal intervals, and a magnetic field is generated in the axial direction of the stator. A coil wound around the outer periphery of the stator piece and magnets of a multi-pole pair having different poles arranged so as to sandwich the coil in each of the outer rotor and the inner rotor having the double rotor structure in the stator axial direction. It is characterized by comprising an outer magnet and an inner magnet.

A second aspect of the present invention is characterized in that the stator piece has a fan-shaped cross section in which the outer rotor side is wider than the inner rotor side.

According to a third aspect of the present invention, in the stator piece, the number of pole pairs of the outer rotor is P0, the number of pole pairs of the inner rotor is P1, the number of drive phases of the outer rotor is M0, and the number of the inner rotor is P0. When the number of drive phases is M1, it is characterized in that the number is arranged to be half the least common multiple of P0 × M0 and P1 × M1.

According to a fourth aspect of the present invention, in the coil wound around the stator piece, the bracket is passed through a gap formed in the circumferential direction between the stator pieces adjacent to each other in the axial direction. It is characterized by being taken out to the side.

According to a fifth aspect of the present invention, stator pieces circumferentially arranged at equal intervals are fixed by fastening brackets installed at both ends in the axial direction of the stator with stator support bolts. The stator support bolt is
It is characterized in that it is arranged in an air gap formed between the stator pieces adjacent in the circumferential direction and penetrating in the axial direction.

According to a sixth aspect of the present invention, the stator piece has a fan-shaped cross section in which the outer rotor side is wider than the inner rotor side, and the stator support bolt is provided inside the fan-shaped cross section of the stator piece. It is characterized by penetrating.

A seventh aspect of the present invention is characterized in that two magnets having different poles, which compose one pole pair of the outer magnet and the inner magnet, are arranged offset from each other in the axial direction of the stator. And

[0014]

According to the first aspect of the present invention, since the magnetic field passing through the stator is directed in the axial direction of the stator, the magnetic flux traveling to the outer rotor passes from the stator through the gap between the stator and the outer rotor. Since the magnetic flux traveling to the outer rotor and the magnetic flux traveling to the inner rotor reaches the inner rotor through the gap between the stator and the stator and the inner rotor, the magnetic field resistance is reduced as compared with the conventional rotary electric machine.

According to the second aspect of the present invention, the stator structure is composed of a stator piece having a fan-shaped cross section in which the outer rotor side is wider than the inner rotor side, and thus the air gap between the stator and the outer rotor and the air gap between the stator and the inner rotor. It is possible to minimize the magnetic resistance of the.

According to the third invention, when the number of pole pairs of the outer rotor is P0, the number of pole pairs of the inner rotor is P1, the number of drive phases of the outer rotor is M0, and the number of drive phases of the inner rotor is M1, P0xM0 and P1xM
Since the stator pieces are arranged in half as many as the least common multiple of 1, the stator cross-sectional area per pole can be made twice as large as that of the above-mentioned conventional example in the cross section of the rotary electric machine cut perpendicularly to the axial direction. The internal magnetic flux density can be reduced.

According to the fourth aspect of the present invention, since the axially penetrating air gap is formed between the stator pieces that are adjacent to each other in the circumferential direction, the coil wound around the outer circumference of the stator piece from the air gap is provided on the bracket side. Therefore, the length in the axial direction can be particularly shortened as compared with the conventional example.

According to the fifth aspect of the invention, the stator support bolts for fixing the stator pieces circumferentially arranged at equal intervals between the brackets installed at both ends in the axial direction of the stator are provided between the stator pieces adjacent in the circumferential direction. Since the air gap formed in the axial direction is arranged so as not to affect the magnetic field, no loss occurs due to the generation of the eddy current in the stator support bolt, and the overall efficiency of the rotating electric machine is improved.

According to the sixth aspect of the invention, since the stator support bolt penetrates the inside of the fan-shaped cross section of the stator piece having a fan-shaped cross section in which the outer rotor side is wider than the inner rotor side, the magnetic field changes due to changes in the magnetic field. The eddy current generated in the stator support bolt flows in a plane perpendicular to the direction of the magnetic field, and the electric resistance value of the stator support bolt is determined according to the diameter of the stator support bolt.
Eddy current is reduced.

According to the seventh aspect of the invention, the two magnets having different polarities forming the one pole pair of the outer magnet and the inner magnet are arranged offset from each other in the axial direction of the stator, so that the rotor skew is realized. It is possible to reduce the torque ripple.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an axial sectional view showing the basic configuration of a rotating electric machine according to a first embodiment of the present invention, and FIG. 2 is a radial sectional view showing the basic configuration of a rotating electric machine according to the first embodiment of the present invention. is there. As shown in FIGS. 1 and 2, the rotating electric machine of the present embodiment has a double rotor structure in which an inner rotor 2 and an outer rotor 3 are coaxially arranged on both the inner and outer circumferences of a stator 1. It is configured as an electric machine.

The stator 1 is, for example, a stator piece 4 which is an iron powder magnetic core, brackets 5 which are respectively installed at both ends in the axial direction of the stator, and a bracket 5 at both ends, which are fastened to each other to form a circle as shown in FIG. Supporting bolts 6 for fixing a plurality of stator pieces 4 arranged at regular intervals, a coil 7 wound around the outer circumference of the stator piece 4 so as to generate a magnetic field in the axial direction of the stator, an outer rotor 3 and an inner rotor. The outer magnet 8 and the inner magnet 9 are composed of magnets 8N, 8S and 9N, 9S of multipole pairs having mutually different polarities, which are arranged so as to sandwich the coil 7 in each of the two.
As shown in FIG. 2, the stator support bolts 6 are arranged in an axial gap formed between the stator pieces adjacent to each other in the circumferential direction. Regarding the rotating electric machine having a double rotor structure in which rotors are coaxially arranged on both the inner circumference and the outer circumference of the stator, for example,
Preprints of Academic Lecture Meeting of Japan Society of Automotive Engineers No.104
-00 ", the paper" Possibilities of multi-current motor with multiple current drive and its application to hybrid vehicles ".

Next, the operation of the rotating electric machine of this embodiment will be described. First, when a current is supplied to the coil 7 wound around the stator piece 4 of the stator 1, a magnetic field is generated. At this time, the coil 7 is supplied with a composite current in which currents synchronized with the respective positions of the outer rotor 3 and the inner rotor 2 are superimposed. By supplying this composite current,
The magnetic field generated in the rotating electric machine becomes a composite magnetic field.

The composite magnetic field generated by the coil 7 advances to the right in the axial direction of FIG. 1 in the stator 1 and is attracted to the outer magnet 8 and the inner magnet 9 to change the directions of the respective magnetic fields. It should be noted that, here, the fact that the composite magnetic field is appropriately separated from the outer magnet 8 and the inner magnet 9 is disclosed in the related arts such as the above-mentioned conventional examples and the above-mentioned papers.

Magnetic fields suitable for the outer rotor 3 and the inner rotor 2 separated from the composite magnetic field attract the outer magnet 8 and the inner magnet 9, respectively, or to the outer magnet 8 and the inner magnet 9, respectively. By being attracted, an electromagnetic force is generated in each of the outer rotor 3 and the inner rotor 2, and torque is generated. The magnetic fluxes that have passed through the outer magnet 8 and the inner magnet 9 respectively advance from the axial right side to the left side inside the outer rotor 3 and the inner rotor 2, pass through the outer magnet 8 and the inner magnet 9 again, and pass through the stator 1 again. Return to inside.

The series of magnetic field loops described above is shown in FIG.
It can be represented by the equivalent magnetic circuit shown in. Figure 3
In (a), the voltage source corresponds to the magnetomotive force of each magnet,
The resistance corresponds to the air gap between the stator 1 and each rotor. However, since the magnetic resistance in the stator and in each rotor has a magnetic permeability higher than that of air, it is not shown in FIG. 3A and can be actually ignored. On the other hand, the above conventional example can be represented by an equivalent magnetic circuit shown in FIG. In this equivalent magnetic circuit,
Compared with the equivalent magnetic circuit of (a), the resistance corresponding to the air gap between the adjacent stators, which is the passage of the magnetic field, is increased.

Therefore, FIG. 3 (a) and FIG. 3 (b)
As is clear from the comparison of
The magnetic resistance is smaller than that of the conventional rotary electric machine.
Such a reduction in magnetic resistance is an effect peculiar to the present invention, which is obtained by the rotating electric machine of the present embodiment having a structure in which the air gap between adjacent stators is not used as a magnetic field passage. In the rotating electric machine of the present embodiment, the stator structure including the stator piece 4 having a fan-shaped cross section in which the outer rotor side is wider than the inner rotor side is adopted, so that the gap between the stator and the outer rotor and the stator and the inner rotor are It is possible to minimize the magnetic resistance of the interspace.

The equivalent magnetic circuit of FIG. 3A will be described in more detail. In this configuration, when the outer rotor is driven in three phases and the inner rotor is driven in six phases, the number of stator pieces required is: the number of pole pairs of the outer rotor P0 = 4 and the number of pole pairs of the inner rotor P1 = 2 Since the number of drive phases of the outer rotor is M0 = 3 and the number of drive phases of the inner rotor is M1 = 6, the number is half of the least common multiple of P0 × M0 and P1 × M1, that is, six. Therefore, in this embodiment, the number of stator pieces required in the cross section of the rotary electric machine cut perpendicularly to the axial direction is half that of the conventional example, and the magnetic flux density in the stator can be reduced.

Further, in the rotating electric machine of this embodiment,
As a space for arranging the stator support bolts 6 and the coils 7, an axially-formed air gap formed between adjacent stator pieces in the circumferential direction is used. Therefore, when the flow of the magnetic field is considered, the magnetic flux is adjacent to the stator. It does not pass through the interstices. Therefore, even if the stator support bolt 6 is made of a magnetic material, a loss (iron loss) due to the generation of an eddy current in the stator support bolt 6 does not occur, so that the overall efficiency of the rotating electric machine is improved. Also, the coil 7
Is arranged in an axially-formed void that is formed between adjacent stator pieces in the circumferential direction, so that the coil 7 can be easily taken out from the void to the bracket 5 side. Therefore, the axial length is particularly shortened as compared with the conventional example.

FIG. 4 is a radial cross-sectional view showing the principle structure of the essential parts of a rotating electric machine according to the second embodiment of the present invention. As shown in FIG. 4, the rotating electric machine of the present embodiment is configured such that the stator support bolts 6 penetrate the inside of the stator piece 4 in the axial direction.

In the rotating electric machine of the present embodiment, the magnetic field generated by supplying a current to the coil 7 wound around the stator piece 4 of the stator 1 mainly flows in the direction perpendicular to the paper surface of FIG. . In this case, an eddy current is generated inside the stator support bolt 6 in accordance with a change in the magnetic field inside the stator piece 4. However, since the eddy current is generated in the direction around the bolt cross section, the stator support bolt 6 is supported. The electric resistance value of the bolt 6 increases according to the diameter of the stator support bolt, and a large eddy current does not occur. On the other hand, in the case of the above-mentioned conventional example, since the flowing direction of the magnetic field and the axial direction of the stator support bolt are orthogonal to each other, an eddy current flows in the axial direction of the stator support bolt, resulting in a large eddy current.

The flow of the magnetic field in the rotating electric machine of this embodiment will be described in more detail with reference to FIG. 5 which is a sectional view taken along line AA of FIG. 4 and FIG. 6 which is a perspective view showing a portion including the outer rotor and the stator. .

In the rotary electric machine of this embodiment, the flow of the magnetic field is as shown in FIGS. 5 and 6, and inside the stator 1, the outer rotor 3 and the inner rotor 2, the magnetic fields flow parallel to the stator shaft (rotation shaft). A magnetic field flows, and in a gap (air gap) formed between the stator 1 and each rotor, the magnetic field flows in a plane orthogonal to the stator axis.
Such a flow of the magnetic field is different from the above-described conventional example in which the magnetic field flowing direction and the axial direction of the stator support bolt are orthogonal to each other. Therefore, in the rotating electric machine of the present embodiment, only the magnetic field flowing through the void portion shown in FIGS. 5 and 6 becomes the magnetic resistance, so that the eddy current is greatly reduced as compared with the above-mentioned conventional example.

FIG. 7 is a view showing the principle structure of the essential parts of a rotating electric machine according to the third embodiment of the present invention. FIG. 7 shows a state in which magnets 8N and 8S having mutually different polarities that form one pole pair of the outer magnet 8 of the rotating electric machine of the present embodiment are developed on the outer rotor plane, and the vertical direction in FIG. 7 is the axial direction. Corresponding to. As is apparent from FIG. 7, one of the outer magnets 8 is
The two magnets 8N and 8S having different polarities forming the pole pair are
It is arranged offset with respect to the axial direction of the stator. It should be noted that two different poles forming one pole pair of the inner magnet 9 are provided.
Although not shown, the magnets 9N and 9S are arranged offset with respect to the axial direction of the stator, as in the case of the outer magnet 8.

According to the rotating electric machine of this embodiment, the magnetic fields generated by supplying current to the coil (not shown) between the magnet 8N and the magnet 8S shown in FIG. 5 by arranging the magnets in an offset manner as described above. Bends obliquely from the magnet 8N toward the magnet 8S so as to form a predetermined angle with the axial direction, so that rotor skew can be realized and torque ripple can be reduced.

[Brief description of drawings]

FIG. 1 is an axial cross-sectional view showing a theoretical configuration of a rotating electric machine according to a first embodiment of the present invention.

FIG. 2 is a radial cross-sectional view showing the basic configuration of the rotary electric machine according to the first embodiment of the present invention.

3A is an equivalent magnetic circuit of the rotating electric machine of the first embodiment, and FIG. 3B is an equivalent magnetic circuit of the rotating electric machine of the conventional example.

FIG. 4 is a radial cross-sectional view showing a theoretical configuration of a main part of a rotary electric machine according to a second embodiment of the present invention.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a perspective view showing a portion including an outer rotor and a stator of a rotary electric machine according to a second embodiment.

FIG. 7 is a diagram showing a principle configuration of a main part of a rotating electric machine according to a third embodiment of the present invention.

FIG. 8 is a diagram for explaining a flow of a magnetic field of a rotary electric machine of a conventional example.

[Explanation of symbols]

1 stator 2 Inner rotor 3 Outer rotor 4 Stator piece 5 bracket 6 Stator support bolt 7 coils 8 outer magnet 8N, 8S magnet 9 Inner magnet 9N, 9S magnet

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5H603 AA01 BB01 BB02 BB09 BB14                       CA01 CA05 CB01 CC15 CC17                       CD21                 5H621 AA03 BB02 BB07 GA11 HH01                 5H622 AA03 CA02 CA05 CA10 CA11                       CB04 CB06 PP03 PP14

Claims (7)

[Claims] 1. A rotary electric machine having a double rotor structure in which rotors are coaxially arranged on both the inner circumference and the outer circumference of a stator, wherein the stator is installed at a plurality of stator pieces and at both ends in the axial direction of the stator. A bracket for fixing the stator pieces arranged at equal intervals circumferentially, a coil wound around the outer circumference of the stator piece so as to generate a magnetic field in the axial direction of the stator, and an outer having the double rotor structure. A rotating electric machine comprising: an outer magnet and an inner magnet, which are composed of magnets of a multipole pair having mutually different poles and are arranged so as to sandwich the coils in the rotor and the inner rotor, respectively, in the axial direction of the stator. 2. The rotating electric machine according to claim 1, wherein the stator piece has a fan-shaped cross section in which the outer rotor side is wider than the inner rotor side. 3. In the stator piece, when the number of pole pairs of the outer rotor is P0, the number of pole pairs of the inner rotor is P1, the number of drive phases of the outer rotor is M0, and the number of drive phases of the inner rotor is M1. P0 × M0 and P
The rotary electric machine according to claim 1 or 2, wherein the number is arranged by half of the least common multiple of 1 x M1. 4. The coil wound around the stator piece is taken out to the bracket side through an axial gap formed between the stator pieces adjacent in the circumferential direction and penetrating in the axial direction. The rotary electric machine according to claim 1. 5. The stator pieces circumferentially arranged at equal intervals are fixed by fastening stator brackets between brackets installed at both ends in the axial direction of the stator,
The rotating electric machine according to any one of claims 1 to 4, wherein the stator support bolts are arranged in a gap that is formed between adjacent stator pieces in the circumferential direction and penetrates in the axial direction. 6. The stator piece has a fan-shaped cross-sectional shape in which the outer rotor side is wider than the inner rotor side, and the stator support bolt penetrates the inside of the fan-shaped cross section of the stator piece. The rotating electric machine according to 1. 7. The outer magnet and the inner magnet, two magnets having mutually different poles forming one pole pair are arranged offset with respect to the axial direction of the stator. A rotating electric machine according to item 1.