JP5894414B2 - Generator - Google Patents

Description

The present invention relates to a generator that generates power by being coupled to a low-speed output shaft such as a windmill.

The frequency of commercial power is 50 Hz (or 60 Hz). For example, in turbine power generation using a two-pole rotor in thermal power / hydroelectric power generation, high-speed rotation of 3000 rotations / minute is necessary (3600 rotations / minute in the case of 60 Hz). However, in a wind turbine using wind power, high-speed rotation cannot be expected, and the number of rotations is increased by a gear or a multipolar rotor generator is used. If the rotor has 20 poles, it is possible to obtain electric power having the frequency of commercial power even at a low speed of 300 revolutions / minute, and gearless power generation becomes possible.

For example, Patent Document 1 discloses a multipolar generator. This generator has a rotor having a permanent magnet as a magnetic pole and a radiation-shaped stator, and by rotating the rotor, an AC is applied to the armature winding wound around the radial teeth of the stator. A voltage is generated.
In addition to a radial gap generator having a magnetic gap in the radial direction as in Patent Document 1, a generator as shown in Patent Document 2 is known as an axial gap generator having a magnetic gap in the axial direction. ing.

This generator winds up a thin foil-like amorphous band to make an iron core (teeth), and a plurality of magnets are fixed parallel to the rotation axis, and the iron core is arranged on the circumference so as to face this And the edge part of the iron core located in the opposite side to a magnet is being fixed to the yoke (yoke). The space between the iron core and the iron core is filled by resin injection molding.

JP 2000-60092 A JP 2011-91933 A

In order to obtain a predetermined frequency even at low rotation, the number of poles must be increased, but it is difficult to accommodate a large number of poles unless the diameter of the generator is increased. On the other hand, in order to increase the voltage with respect to a predetermined magnetic flux, the number of turns of the winding may be increased, but the length of the stator must be increased. In the axial gap type generator, the teeth are fixed to the yoke on the opposite side of the magnet. As the teeth become longer, the force is increased due to the rotation of the magnet, so this force is increased by the principle of the lever. To support this, the yoke must have a stronger structure in addition to the axial strength in the first place. . The strength can be solved by filling the space between the teeth with a resin mold, but conversely, the generated heat is difficult to escape.

The present applicant has proposed Japanese Patent Application No. 2011-188376 as a technique for multi-polarizing a radial gap generator without strengthening the structure so much. In the generator, when the teeth are lengthened in order to increase the number of windings of the teeth, the diameter of the generator is increased, and the stator pole outer peripheral portion is widened to increase the volume.

Accordingly, an object of the present invention is to provide a multipolar generator that efficiently generates power with a small number of rotations without increasing the size even if the number of turns of the winding is increased with high efficiency.

In order to solve the above-described problems, a generator according to the present invention includes a rotor in which magnetic poles of a plurality of permanent magnets are alternately arranged in the direction of the rotation axis in the center of the rotation axis, and a soft magnetic core. A plurality of stator poles provided with windings, and the stator pole is fixed with the one end of the magnetic circuit of the stator pole facing the magnetic pole of the rotor with respect to the rotation axis center, and a magnetic gap between the magnetic poles A non-magnetic holding plate formed with the other end of the plurality of stator poles, a yoke that magnetically couples the plurality of stator poles together, and the rotating shaft through a bearing bearing, It has a hollow tube that externally connects the holding plate and the yoke.

According to the present invention, the stator pole and the yoke are manufactured separately, and the stator pole is fixed by the holding plate and the hollow tube, so that the structural strength as a generator is provided at a position close to the magnetic gap. Can do. Therefore, since the fulcrum and the action point for this force are close to the moment generated by the magnetic movement, the structure is simplified. Further, since both ends of the stator pole are supported, the length of the stator pole can be increased.

FIG. 1 shows a generator 1 of this embodiment. The generator 1 is an axial gap generator, and a rotor 10 having a permanent magnet as a magnetic pole is fixed to the rotary shaft 2 and rotates between stators 20 and 30 provided with the rotor 10 interposed therebetween. The rotary shaft 2 is housed inside the hollow tube 41 so as to be rotatable via a bearing 43. The rotating shaft 2 is hollow, and a shaft such as a windmill can be directly inserted.

Each of the stators 20 and 30 includes a plurality of stator poles 50 arranged at equiangular intervals around the rotating shaft 2, and a nonmagnetic holding plate that supports one end 50 a of the stator pole 50 on the rotor 10 side of the stator pole 50. 21 and 31, and yokes 22 and 32 that support the stator pole 50 at the other end 50 b of the stator pole 50. The yokes 22 and 32 short-circuit the magnetic flux of each stator pole 50 to the other stator poles 50. A positioning frame, which will be described later, is provided on the stator pole 50 side of the yokes 22 and 32. The support body 60 that supports the hollow tube 41, the support body 70 that supports the hollow tube 42 (see FIG. 3), and the stators 20 and 30 are fixed on a base 80. Are connected by a connecting joint 90.

Hereinafter, the process of assembling the generator 1 will be shown and the structure will be described in detail.
FIG. 2 is a diagram illustrating an assembly process of the stator pole 50. A strip-shaped thin soft magnetic material 52 is wound around the stator core 51 many times. The thinner the electromagnetic steel sheet, the lower the iron loss, and the thinner the electromagnetic steel sheet used as the soft magnetic body 52, the better. An insulating film is applied to the surface of the soft magnetic body 52. Since the stator pole 50 is manufactured by winding the thin soft magnetic body 52, it is possible to eliminate the waste of the material remaining at the time of punching.

In addition, there are two types of magnetic steel sheets: non-oriented magnetic steel sheets and directional magnetic steel sheets. Generally oriented magnetic steel sheets are excellent in frequency characteristics and iron loss, so they are suitable for applications such as high-efficiency and high-performance equipment. Steel plates are used for applications such as rotating machines. In this embodiment, a directional electrical steel sheet having a lower magnetic loss than a non-oriented electrical steel sheet and having a high magnetic permeability is used as the soft magnetic body 52. The easy magnetization direction a of the grain-oriented electrical steel sheet is perpendicular to the length direction of the soft magnetic body 52 (the direction of winding around the stator core 51). This is because the direction of the magnetic circuit formed by the stator pole 50 is matched.

The stator core 51 is slightly longer than the width of the soft magnetic body 52 so that when the soft magnetic body 52 is wound, the end portions 51a can be seen on both sides. On the other hand, the flange 53 having the hole 53a in which the end portion 51a is fitted is mounted from both sides of the stator core 51 around which the soft magnetic body 52 is wound. As the flange 53, a soft magnetic steel plate is used. The winding 54 is wound between the flanges 53 of the iron core formed in this way. In this way, the stator pole 50 is manufactured. The flange 53 serves as one end 50 a and the other end 50 b of the magnetic circuit formed by the stator pole 50.

FIG. 3 is a view showing the assembly of the stators 20 and 30, FIG. 3A shows the stator 20, and FIG. 3B shows the stator 30. The stators 20 and 30 have almost the same configuration, but the stator 20 is slightly longer than the hollow tube 42 on the stator 30 side because the hollow tube 41 is extended to the support 60. Just do it. The holding plates 21 and 31 are non-magnetic stainless steel plates, and the central holes 21a and 31a into which the hollow tubes 41 and 42 are inserted and fixed, and the flanges 53 of the stator pole 50 are inserted and fixed at equal angular intervals therearound. Holes 21b and 31b are provided. The flange 53 on the one end 50a side inserted into the holes 21b and 31b is fixed to the holding plates 21 and 31 by welding, and forms a magnetic gap with the magnetic pole 11a (FIG. 5). On the other hand, the yokes 22 and 32 are provided with positioning frames 23 and 33 on the stator pole 50 side. The positioning frames 23 and 33 also have central holes 23a and 33a communicating with the yokes 22 and 32, and the hollow tubes 41 and 42 are inserted therein. Around the central holes 23a and 33a, holes 23b and 33b into which the flanges 53 on the other end 50b side of the stator pole 50 are inserted are provided at equal angular intervals. For convenience of drawing, the central hole 23a and the hole 23b of the positioning frame 23 are not shown in the drawing, but are the same as those of the positioning frame 33. The positioning frames 23 and 33 may be nonmagnetic or magnetic, and may not be metal. Thus, the attractive force, the repulsive force, and the rotational force with the permanent magnet 11 are supported at the position closest to the point of action (the holding plates 21 and 31). The positioning frames 23 and 33 are inserted into the flange 53 on the other end 50b side of the stator pole 50 and brought into contact with the yokes 22 and 32 for magnetic coupling. The connection structure between the other end 50b of the stator pole 50 and the positioning frames 23 and 33 may be any structure that can withstand its own weight and vibration as long as it receives a load in the axial direction (the direction of the rotating shaft 2).

The yokes 22 and 32 are formed by stacking a plurality of disc-shaped non-oriented electrical steel sheets (soft magnetic materials) by electrical insulation. The non-oriented electrical steel sheet is used because the magnetic flux from the stator pole 50 is introduced by being magnetically coupled to the stator pole 50. The yokes 22 and 32 may be formed in a cylindrical shape by winding a strip of non-oriented electrical steel sheets many times.
FIG. 4 shows the configuration of the rotor 10. The rotor 10 is a combination of two nonmagnetic materials (aluminum) disks 12 and 13 (FIG. 4A). As the permanent magnet 11, a cylindrical neodymium magnet 14 is used to increase the magnetic flux density. A yoke 15 (soft magnetic material) is magnetically coupled to the magnetic poles on both sides. The yoke 15 includes a truncated cone in which one end surface has a larger area than the other end surface, and the cross-sectional area sequentially decreases from the one end surface toward the other end surface. One end face of the yoke 15 having a large area is magnetically coupled to the permanent magnet (FIG. 4C). The discs 12 and 13 are provided with holes 11 b for accommodating the permanent magnets 11, and the yoke 15 exposes the other end face of a small area from the holes 11 b to the surfaces of the discs 12 and 13. Since the diameter of the exposed yoke 15 is smaller than the diameter on the neodymium magnet 14 side, this reduces the area of the magnetic pole surface of the neodymium magnet 14 and increases the magnetic flux density.

FIG. 5 shows a state in which the rotor 10 is fixed to the rotating shaft 2 and the stator 30 is connected to the stator 20 by the connecting joint 90 with respect to the generator 1 to which the stator 20 is attached. The rotor 10 is a disk, and magnetic poles 11a are formed by yokes 15 of a plurality of permanent magnets 11 so that N poles and S poles appear alternately on the disk surface at equal angular intervals. In this embodiment, the number of magnetic poles is 24 for 18 stator poles.

FIG. 6 is a cross-sectional view of the generator 1. One end 50a of the stator pole 50 faces each other, and the permanent magnet 11 of the rotor 10 is disposed therebetween, and a magnetic gap is formed between the front and back magnetic poles 11a and one end 50a of the stator pole 50, respectively. The rotary shaft 2 is housed through bearings 43 and 45 disposed in the hollow tubes 41 and 42, and the hollow tubes 41 and 42 are formed in the central holes of the yokes 22 and 32 and the holding plates 21 and 31. The two are inserted into each of them. The rotating shaft 2 transmits a rotational force to the rotor 10. The bearing 45 disposed in the immediate vicinity of the holding plate 21 suppresses vibration generated in the rotor 10 due to rotation. The rotating shaft 2 is hollow, and the rotating shaft of the windmill is inserted therein.

FIG. 7 shows the magnetic flux due to the magnetic pole 11 a flowing through the stator 20. In the figure, a permanent magnet 11 is arranged in parallel to the direction of the rotating shaft 2 with the rotor 10 interposed therebetween, and both magnetic poles 11 a are arranged on the front and back surfaces of the rotor 10. And the stator pole 50 (stator 20 side) arrange | positioned at the surface side of the rotor 10 is arrange | positioned in a straight line with the stator pole 50 (stator 30 side) arrange | positioned at a back side. In this embodiment, the yokes 22 and 32 are used as passages for coupling the magnetic flux of one stator pole 50 to another stator pole 50. That is, although the magnetic pole 11a and the stator pole 50 are in a relatively rotating state, the total magnetic flux emitted from the magnetic pole 11a and reaching the yoke 22 through the stator pole 50 becomes substantially zero in each yoke. There will be almost no magnetic flux leaking out of 22. In other words, the magnetic flux generated from the magnetic pole 11a flows through the magnetic circuit passing through the soft magnetic body by the stator pole 50 and the yoke 22 through the entire process except the axial gap and a part of the gap for electrical insulation. .

A similar magnetic circuit is formed on the stator 30 side with the magnetic pole 11a on the back side. For this reason, power generation using both the front and back magnetic poles of the permanent magnet 11 can be performed. If the length of the generator 1 must be shortened, the stator 30 side may be deleted, and a soft magnetic material that short-circuits the magnetic pole 11a on the back side of the rotor 10 may be provided instead. As described above, in this embodiment, since the magnetic pole that generated the magnetic flux does not have a soft magnetic material that forms a feedback loop for returning the magnetic flux, the diameter of the generator 1 is reduced. Further, in order to increase the number of turns of the coil in order to increase the voltage, it is only necessary to increase the length of the stator pole 50, and the length of the generator is increased only by increasing the length of the stator pole 50. is there. Further, since the stator pole 50 (stator 20 side) and the stator pole 50 (stator 30 side) arranged on the back side are in a straight line, in-phase voltage is generated, and these windings are connected in series. By connecting, a large voltage can be obtained as one stator.

When the generator 1 is used for wind power generation with a low rotational speed, the rotational speed is low and the period of the alternating magnetic field generated thereby is also long. Therefore, the eddy current generated in the flange and the holding plates 21 and 31 does not increase, and the iron loss at this point is small. Furthermore, non-magnetic materials such as stainless steel are less affected by eddy currents because their electrical resistance is about 100 times that of copper. As the holding plates 21 and 31, a plate made of a nonmagnetic material such as a reinforced resin can be used.
On the other hand, in the stator pole 50 and the yokes 22 and 32 that occupy most of the length of the magnetic circuit, the electromagnetic steel sheets overlap with each other in an insulated state, so that the iron loss is small.

Further, when the rotor 10 rotates, the stator pole 50 receives a force that vibrates in the circumferential direction, and this is supported by the holding plates 21 and 31 where the vibration occurs.

The yokes 22 and 32 are in contact with the outer surface of the flange 53 on the other end 50 b side of the stator pole 50. Since the yokes 22 and 32 and the stator pole 50 are not structural materials, the positioning frames 23 and 33 may have a mechanism for holding the yokes 22 and 32 against the stator pole 50 so as not to be displaced.

In the operation of the generator 1, the magnetic flux generated from the magnetic pole 11 a reaches the flange 53 through the magnetic gap. The lines of magnetic force reaching the flange 53 on the one end 50a side reach the flange 53 on the other end 50b side along the direction of easy magnetization of the soft magnetic material, and move from here to the yoke 22 or 32. Then, after reaching the other stator pole 50 again, it returns to the other magnetic pole 11a.

In the above embodiment, the stator core 51 is used for manufacturing convenience, but this need not be used. For example, a stator pole may be produced by winding a soft magnetic material without the stator core 51. Further, as in Patent Document 2, a flange 53 may be attached by inserting a stator pole into a winding made in advance.

The nonmagnetic holding plates 21 and 31 may not have the through holes 21b and 31b. In this case, although the gap of the magnetic gap is widened, the strength of the holding plates 21 and 31 is enhanced. Further, although the holding plates 21 and 31 are fixed by welding, the flange may be fixed to the holding plate by bolts.

In the present embodiment, the stator pole 50 having 18 poles is shown, but a larger number of poles may be used. On the other hand, the number of poles of the permanent magnet 11 is set so that the number of facings is as small as possible so as to reduce cogging. The hollow tube 42 may not be hollow as long as the rotary shaft 2 is not inserted.

Since the stator poles 50 of the stators 20 and 30 are arranged on one line and a synchronized voltage flows, a double voltage can be obtained by connecting them in series.

In the generator 1 according to this embodiment, the stators 20 and 30 are not radially arranged in the circumferential direction with respect to the rotor 10 provided with the magnetic pole 11a, and are arranged in parallel to the rotation axis direction. When there are few surfaces and it is directly connected to or parallel to the axis of rotation of a windmill or the like, it is less likely to receive wind pressure.

1 is a perspective view of a generator 1. FIG. It is a figure which shows the assembly of a stator pole. It is a figure which shows the assembly of a stator. It is a figure which shows the assembly of a rotor. It is a figure which shows the assembly of a stator and a rotor. It is a cross-sectional exploded view of a generator. It is a figure explaining the flow of magnetic flux.

DESCRIPTION OF SYMBOLS 1 Generator 2 Rotating shaft 10 Rotor 11 Permanent magnet 20, 30 Stator 21, 31 Holding plate 22, 32 Yoke 41, 42 Hollow tube 50 Stator pole

Claims (7)

A rotor in which the magnetic poles of a plurality of permanent magnets are alternately arranged in the rotation axis direction in the direction of the rotation axis;
A number of stator poles wound on a soft magnetic iron core;
A non-magnetic holding plate in which one end of a magnetic circuit of the stator pole is directed toward the magnetic pole of the rotor with respect to the rotation axis center, and a magnetic gap is formed between the magnetic pole and the magnetic pole.
A yoke that abuts the other ends of the plurality of stator poles and magnetically couples the plurality of stator poles;
A generator comprising: a rotary tube that includes a rotary shaft that includes a bearing shaft and that connects and holds the holding plate and a yoke.
2. The generator according to claim 1, wherein the plurality of stator poles are stator poles each having a winding wound on an iron core wound with a strip-shaped electromagnetic steel sheet.
The generator according to claim 1, wherein the strip-shaped electromagnetic steel plate of the stator pole is a directional magnetic steel plate, and an easy magnetization axis is made to coincide with a direction of a magnetic circuit of the stator pole.
The magnetic poles of each permanent magnet of the rotor are arranged on the front and back of the rotor,
The non-magnetic holding plate to which the stator pole is fixed is provided for each of the front and back surfaces of the rotor,
The yokes are respectively arranged with respect to the other ends of the plurality of stator poles of the non-magnetic holding plates provided on the front and back surfaces of the rotor, and each of the yokes abuts the plurality of stator poles. 2. The generator according to claim 1, wherein the stator poles are coupled to each other magnetically.
5. The stator pole on the front side of the rotor and the stator pole on the back side of the rotor are arranged in a straight line, and the windings of the stator pole arranged on the straight line are connected in series. Generator.
2. The generator according to claim 1, wherein the rotating shaft is hollow.
A soft magnetic yoke having a shape between one end face and the other end face parallel to the one end face and having a cross-sectional area parallel to these end faces that gradually decreases from one end face to the other end face. 2. The generator according to claim 1, wherein the one end face is magnetically coupled to the permanent magnet, and the other end face is the magnetic pole disposed on the rotor.