Liquid-cooled generator

Abstract

By immersing at least a portion of the power-generating part in liquid, the degradation of efficiency due to heat generation can be suppressed, and a generator capable of consistently generating power at high efficiency is provided. [Solution] The electromotive force means comprises a permanent magnet in which magnetic poles are arranged radially around a rotation axis and alternately along the circumferential direction, a coil made of conductive wire wound around an electrically insulated bobbin, a magnetic flux applying means composed of a plurality of metal pieces that apply the magnetic flux generated from the permanent magnet to the coil, and an attractive force means composed of a plurality of attracted pieces arranged radially around the rotation axis and magnetized by the permanent magnet, fixed to a non-magnetic base, wherein the coil and the magnetic flux applying means are stators, and at least the stators are immersed and cooled by a cooling liquid consisting of an insulating liquid, and the cooling liquid is circulated and cooled by a heat exchanger.

Description

Technical Field

[0004] , , , ,

[0001] The present invention relates to a liquid-cooled generator, and more particularly to a technique for reducing heat generation of a generator with reduced cogging torque.

Background Art

[0002] Conventionally, by using a generator that reduces the influence exerted on the rotating shaft by the so-called cogging torque generated by means of adsorbing a yoke to supply a magnetic field, high-efficiency power generation has been possible. However, since the influence of cogging is small, when the rotation speed becomes high and the power generation amount increases, it has been pointed out that problems such as the coil of the generator becoming high temperature and consequently the efficiency decreasing occur. Therefore, a technique for suppressing the temperature rise of coils and the like has been demanded even when the generator is rotated at high speed.

[0003] Regarding such a technique, various proposals have been made conventionally. For example, a generator (see Patent Document 1) that reduces the influence exerted on the rotating shaft by the cogging torque generated by means of adsorbing a yoke to supply a magnetic field has been proposed and has become a known technique. More specifically, a power generation means including magnets in which an even number of magnetic poles are arranged in the rotation direction of the rotating shaft, iron pieces corresponding to the even number of magnetic poles of the magnets being close to the magnetic poles, and a yoke arranged coaxially with the rotating shaft is connected to the rotating shaft by 4 or more, and the magnets and yokes of one power generation means and the magnets and yokes of the other power generation means are relatively rotated so as to cancel the attracting force between the iron piece of the magnet and yoke of one power generation means and the attracting force between the iron piece of the magnet and yoke of the other power generation means. However, there is no description regarding the countermeasure when the coil becomes high temperature, and the above problems have not been solved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] In view of the above problems, the present invention aims to provide a generator that can always generate electricity with high efficiency by suppressing efficiency degradation due to heat generation by immersing at least a part of the generating portion in liquid. [Means for solving the problem]

[0006] To solve the above-mentioned problems, the present invention provides a generator comprising: a permanent magnet having magnetic poles arranged radially around a rotation axis and alternately along the circumferential direction; a coil formed by winding conductive wire around an electrically insulated bobbin; a magnetic flux applying means composed of a plurality of metal pieces that apply the magnetic flux generated from the permanent magnet to the coil; and an attractive means arranged radially around the rotation axis, wherein a plurality of attracted pieces magnetized by the permanent magnet are fixed to a non-magnetic base. The permanent magnet rotates with the rotation axis, the magnetic flux applying means is positioned on one broad surface side of the permanent magnet, and the attractive means is positioned on the other broad surface side of the permanent magnet. The magnetic flux applying means includes a first yoke for guiding the magnetic flux to the pole of the coil that is farther from the permanent magnet, and for guiding the magnetic flux to the pole of the coil that is closer to the permanent magnet. The system consists of a first yoke and a second yoke, each of which is provided with a plurality of field iron pieces for obtaining magnetic flux from the permanent magnet, the number of field iron pieces and the number of pieces to be attracted are equal, the field iron pieces and pieces to be attracted are arranged at equal angles with respect to the rotation axis, and the pieces to be attracted are positioned at an intermediate angle between adjacent field iron pieces, so that the field iron pieces and pieces to be attracted are offset by equal angles, the electromotive force is connected to the same rotation axis in multiple units, and in order to cancel out cogging torque, when the position of the pole of the permanent magnet of one electromotive force is opposite the position of the field iron piece, the position of the pole of the permanent magnet of at least one other electromotive force is offset from the position opposite the field iron piece and also offset from the position opposite the piece to be attracted, the coil and the magnetic flux application means are stators, The cooling unit comprises a coolant storage container, a heat exchanger, and piping connecting the coolant storage container and the heat exchanger. The cooling unit is filled with a coolant consisting of an insulating liquid, and the coolant circulates through a closed space consisting of the coolant storage container, the heat exchanger, and the piping, and is cooled by the heat exchanger. The coolant storage container isat least the Covering the coil, the coil Cooled by immersion in a coolant. be Take action.

[0007] Furthermore, the present invention employs a method in which the coolant is stored in a container corresponding to each of the stators, a portion of the container passes between the magnetic flux applying means and the permanent magnet, and the thickness of the container between the magnetic flux applying means and the permanent magnet is such that the container does not come into contact with the permanent magnet.

[0008] Furthermore, in the present invention, the cooling liquid is stored in a container corresponding to each of the stators, and the magnetic flux application means comprises a field iron piece that obtains magnetic flux from the permanent magnet, a coil side plate portion that applies magnetic flux to the coil, and a connecting portion that connects the field iron piece and the coil side plate portion, the container has a hole for exposing the field iron piece to the outside of the container, the field iron piece is exposed to the outside of the container, and a part of the connecting portion is a means that deforms toward the permanent magnet in accordance with the amount of exposure of the field iron piece.

[0009] Furthermore, the present invention employs a method in which the rotating part is a cylindrical permanent magnet whose axis is in the axial direction of the rotation shaft, and the entire electromotive force means is cooled by liquid immersion.

[0010] Furthermore, the present invention employs a method in which the outside of the housing on which the electromotive force is mounted is immersion-cooled, and a portion of the metal piece is in contact with the housing.

[0011] Furthermore, the present invention employs a method in which the number of electromotive force devices is a multiple of 4. [Effects of the Invention]

[0012] According to the liquid-cooled generator of the present invention, in high-efficiency power generation, it is possible to suppress efficiency degradation due to heat generation and to always perform high-efficiency power generation. [Brief explanation of the drawing]

[0013] [Figure 1] This is an overall cross-sectional view showing an embodiment of a liquid-cooled generator according to the present invention. [Figure 2] It is an overall cross-sectional view showing another embodiment of the liquid-cooled generator according to the present invention. [Figure 3] It is an overall cross-sectional view showing another embodiment of the liquid-cooled generator according to the present invention. [Figure 4] It is a cross-sectional view showing details of the coil portion in the liquid-cooled generator according to the present invention. [Figure 5] It is a perspective view showing the structure of the electromotive means in the liquid-cooled generator according to the present invention. [Figure 6] It is an exploded view showing the structure of the electromotive means in the liquid-cooled generator according to the present invention. [Figure 7] It is a schematic cross-sectional view showing the positional relationship among the field magnet pieces, permanent magnets, and attracted pieces of the generator in the liquid-cooled generator according to the present invention.

Embodiments for Carrying Out the Invention

[0014] The liquid-cooled generator according to the present invention is characterized in that by immersing at least a part of the electromotive portion in a liquid, heat generation due to power generation is reduced, and power generation with high efficiency can be continuously performed. Hereinafter, embodiments of the liquid-cooled generator according to the present invention will be described based on the drawings. Note that the liquid-cooled generator according to the present invention is not limited to the embodiments described below, and can be appropriately changed within the scope of the technical idea of the present invention, that is, within the scope of shapes, dimensions, structures, uses, etc. that can exhibit the same operational effects. For example, it is not limited to generators, but is also suitable for motors, rotary machines, etc., and is expected to be used for such applications. In addition, in the description of this embodiment, the coolant storage portion is an expression when there is one coolant tank, and the coolant storage container represents each tank when there are multiple coolant tanks.

[0015] First, the electromotive means 10 will be described along FIGS. 5 to 7. The charging means 10 includes a permanent magnet 14 that is radially arranged with respect to a rotating shaft 12 to which an external rotational force is transmitted, and in which magnetic poles are alternately arranged along the circumferential direction, a coil 30 in which a conductive wire is wound around an electrically insulated bobbin 31, a yoke 20 that applies magnetic flux generated from the permanent magnet 14 to the coil 30, and an attracting means 19 that is radially arranged with respect to the rotating shaft 12 and includes a plurality of attracted pieces 18 magnetized by the permanent magnet 14. The arrow R shown in FIG. 5 indicates the rotation direction of the rotating shaft and the permanent magnet 14.

[0016] As shown in FIG. 5, the permanent magnet 14 is formed in a disk shape with an appropriate thickness. The center of the permanent magnet 14 is fixed by the rotating shaft 12. In the permanent magnet 14, substantially fan-shaped N poles and S poles that are separated by an angle of 45 degrees around the rotating shaft 12 are alternately arranged. Opposite magnetic poles are formed on opposite surfaces in the thickness direction of this disk-shaped permanent magnet 14.

[0017] The volume and magnetic flux density of the magnetic poles of each permanent magnet 14 are equal. The material constituting the permanent magnet 14 is, for example, ferrite or neodymium. In the permanent magnet 14, one side surface close to the yoke 20 is expressed as the front surface or one wide surface side, and the other side surface close to the attracting means 19 is expressed as the back surface or the other wide surface side.

[0018] The magnetic flux density of the permanent magnet 14 is considered to be the strongest at the center of the surface of each magnetic pole. When explaining the position of the permanent magnet 14, the position of the center of the surface of this magnetic pole is used as the reference for the pitch. Also, for the interpole piece 26 and the attracted piece 18, the pitch lines that extend radially from the rotating shaft 12 at the center of each area are used as the reference in the explanation of each position.

[0019] The yoke 20 is a magnetic flux application means for transmitting the magnetic flux of the permanent magnet to the coil. The yoke 20 is composed of a first yoke 20a and a second yoke 20b, which are a plurality of metal pieces. The first yoke 20a is the part that guides the magnetic flux to the pole of the coil 30 that is farther from the permanent magnet 14, and the second yoke 20b is the part that guides the magnetic flux to the pole of the coil 30 that is closer to the permanent magnet 14. The first yoke 20a consists of a first iron piece 22, which is a field iron piece 26 that obtains magnetic flux from the permanent magnet 14; a long plate 22a, which is a connecting portion 27 that guides the magnetic flux; and an axial peripheral portion 22b, which is a coil side plate portion 28 that guides the magnetic flux to the pole. The axial peripheral portion 22b is positioned on the pole side of the coil 30 that is furthest from the permanent magnet 14. The long plate 22a passes through the side of the coil 30. The shape of the first yoke 20a is such that four long plates 22a, which are integrated at the periphery 22b of the rotating shaft 12, are bent into an L-shape at their ends to form the first iron piece 22. The first iron piece 22 is positioned close to the front surface of the permanent magnet 14 so as to be parallel to it. The gap between the permanent magnet 14 and the first iron piece 22, which is the end of the magnetic flux application means, is approximately 2 millimeters. Four long plates 22a are arranged radially around the rotation axis 12 at 90-degree angle pitches, covering the coil 30 from the outside. Thus, the first iron pieces 22 are arranged at 90-degree angle pitches around the rotation axis 12.

[0020] The second yoke 20b consists of a second iron piece 24, which is a field iron piece 26 that obtains magnetic flux from the permanent magnet 14; a short plate 24a, which is a connecting part 27 that guides the magnetic flux; and an axial peripheral part 24b, which is a coil side plate part 28 that guides the magnetic flux to the pole. The axial peripheral part 24b is positioned on the pole side of the coil 30 that is closer to the permanent magnet 14. The short plate 24a connects the second iron piece 24 and the axial peripheral part 24b over a short distance. The second iron piece 24, from the short plate 24a to the periphery portion 24b, is a single plane. The central part of the periphery portion 24b may be bent in an L-shape toward the hollow portion of the bobbin 31 (the part through which the rotating shaft 12 passes). This second iron piece 24 is positioned close to the front surface of the permanent magnet 14, parallel to it. It is deployed radially around the rotation axis 12 at a 90-degree angle pitch. In other words, the second iron piece 24 is arranged at a 90-degree angle pitch around the rotation axis 12.

[0021] The first iron piece 22 and the second iron piece 24 are connected to each other, with a 45-degree angle offset from each other around the rotation axis 12. Furthermore, the first iron piece 22 and the second iron piece 24 are rotatably connected to the rotation axis 12 via bearings 32.

[0022] The coil 30 is formed by winding conductive wire around an annular bobbin 31 made of synthetic resin, which is electrically insulated. The stator 11 is formed by fixing the first yoke 20a and the second yoke 20b to this coil 30. The integrated stator 11 is fixed to the rotating shaft 12 via a bearing 32, with the rotating shaft 12 as its axis, so that the rotating shaft 12 can rotate freely. The higher the conductivity, the more efficient power generation is possible. Therefore, it is preferable to select a material with high conductivity as the conductive wire. For example, copper wire can be cited because it is highly conductive, inexpensive, and readily available. Alternatively, platinum or gold wire, which have even higher conductivity, could be used, or new materials with high conductivity could be employed.

[0023] The attractive means 19 consists of a fixed base and eight pieces to be attracted 18. As shown in Figure 6, a disc-shaped fixed base of moderate thickness is pivotally supported on the back side of the permanent magnet 14, around the rotation axis 12. This fixed base is made of a non-magnetic material and is not magnetized by the permanent magnet 14. In this embodiment, it is made of synthetic resin. In other words, the attractive means 19 has a configuration in which multiple pieces to be attracted, which are arranged radially around a rotation axis and magnetized by permanent magnets, are fixed to a non-magnetic base.

[0024] Eight rectangular magnet-attached pieces 18, made of the same material as the field iron pieces 26, are arranged on the surface of the fixed base 36 facing the permanent magnet 14. The magnet-attached pieces 18 are fixed to the fixed base so as to radiate outwards from the rotation axis 12 at positions corresponding to the 2x intervals between each iron piece in the field iron pieces 26. The fixed base is connected to the rotation axis 12 via bearings 32. Therefore, the fixed base is rotatable around the rotation axis 12.

[0025] In the entire power generation means 10, the permanent magnet 14 is rotatable as a single unit with the rotating shaft 12. The permanent magnet 14 is a thin disc shape, and a magnetic flux application means 20 is positioned on one of its broad surfaces. An attractive force means 19 is positioned on the other broad surface. The magnetic flux application means 20 and the attractive force means 19 are fixed to the base, and only the permanent magnet 14 and the rotating shaft 12 rotate. The bearing for the rotation of the rotating shaft 12 is provided inside the magnetic flux application means 20 and the attractive force means 19. When multiple electromotive force devices 10 are arranged, the permanent magnets 14 of each electromotive force device 10 are fixed to a single rotating shaft 12, and the magnetic flux applying devices 20 and attractive devices 19 are arranged on both sides thereof.

[0026] In this configuration, the magnetic flux applied to the field iron piece 26 by the permanent magnet 14 crosses the coil 30 in the axial direction, generating an electromotive force in the coil 30. As the permanent magnet 14 rotates together with the rotation axis 12, the magnetic poles applied to the field iron piece 26 alternately change, and the direction of the magnetic flux crossing the coil 30 in the axial direction alternately reverses, continuously generating an electromotive force in the coil 30.

[0027] The distance between the permanent magnet 14 and the object to be attracted 18 is the same as the distance between the field iron piece 26 and the permanent magnet 14. For example, in the embodiment of this product, it is approximately 2 millimeters. Also, the area of ​​the object to be attracted 18 is the same as the area of ​​the field iron piece 26. Furthermore, it is desirable that the shape and area of ​​the object to be attracted 18 be the same as those of the field iron piece 26.

[0028] The positional relationship between the field iron pieces 26 and the attached pieces 18 will now be explained. The eight field iron pieces 26 are evenly spaced around the rotation axis 12 at a 45-degree angle pitch, which divides the circumference into eight parts. Similarly, the eight attached pieces 18 are evenly spaced around the rotation axis 12 at a 45-degree angle pitch, which divides the circumference into eight parts. Furthermore, the eight field iron pieces 26 and the eight attached pieces 18 are positioned with an angle offset of 22.5 degrees, which is half of the 45-degree angle. In other words, the number of field iron pieces that generate magnetic flux from the permanent magnets in the first and second yokes is equal to the number of attached pieces, which is eight, and the field iron pieces and attached pieces are arranged at equal angles with respect to the axis of rotation. Furthermore, the angle between adjacent field iron pieces is 45 degrees, and the piece to be attracted is positioned at an intermediate angle of 22.5 degrees. With this configuration, the field iron pieces and the piece to be attracted are positioned at equal angles.

[0029] The stator 11, which integrates the yoke 20 and the coil 30, and the fixed base 36 to which the piece to be attracted 18 is fixed are fixed by a base 39. Therefore, the positions of the field iron piece 26 and the piece to be attracted 18 are fixed with a 22.5-degree angle difference without any change in position.

[0030] The operation of this embodiment will now be explained. In this generator 10, the magnetic flux applied to the field iron piece 26 by the permanent magnet 14 crosses the coil 30 in the axial direction, generating an electromotive force in the coil 30. As the permanent magnet 14 rotates together with the rotation axis 12, the magnetic poles applied to the field iron piece 26 change alternately, and the direction of the magnetic flux crossing the coil 30 in the axial direction alternately reverses, continuously generating an electromotive force in the coil 30.

[0031] Figure 7 schematically shows a cross-section of a generator 10 according to one embodiment of the present invention, in which the permanent magnet 14 is rotating with the field iron piece 26 and the attached piece 18 fixed in place. The direction of rotation of the permanent magnet 14 is the direction of arrow R shown in Figure 1. In Figure 7, this rotation of the permanent magnet 14 is represented by the movement of the permanent magnet 14 from bottom to top.

[0032] Figure 7(a) shows the state in which the permanent magnet 14 exerts a strong attractive force on the field iron piece 26. Figure 7(b) shows the state in which the permanent magnet 14 has been rotated by 11.25 degrees around the rotation axis 12, which is 22.5 degrees divided into two parts, from the state in (a). Figure 7(c) shows the state in which the permanent magnet 14 has been rotated by another 11.25 degrees from the state in (b). Figure 7(d) shows the state in which the permanent magnet 14 has been rotated by another 11.25 degrees from the state in (c). Below, the positional relationship between the permanent magnet 14, indicated by the shaded area in Figure 7, and the field iron piece 26 and the attracted piece 18 will be explained.

[0033] In Figure 7(a), if the span between the field iron pieces 26 is d, then the span between the field iron piece 26 and the attached piece 18 is d / 2. Also, when the permanent magnet 14 is in position (a), let u be the distance in the gap between the permanent magnet 14 and the attached piece 18, and let t be the distance in the gap between the permanent magnet 14 and the field iron piece 26. Also, when the permanent magnet 14 is in position (b), let r be the distance in the gap between the field iron piece 26 and the attached piece 18 and the permanent magnet 14. Here, the lengths of distances t, r, and u are such that t is the shortest and u is the longest.

[0034] In the state shown in Figure 7(a), the field iron piece 26 is separated from the north pole of the permanent magnet 14 by a distance t, so the field iron piece 26 has a strong distribution of south poles, which are the image magnetic poles of the opposite polarity. Also, since the south pole of the permanent magnet 14 is separated from the attached piece 18 by a distance u, the attached piece 18 on both sides of the permanent magnet 14 has a weak distribution of north poles, which are the image magnetic poles of the opposite polarity.

[0035] In the state shown in Figure 7(b), the field iron piece 26 is separated from the north pole of the permanent magnet 14 by a distance r, so a weak south pole, which is the opposite polarity image magnetic pole, is distributed on one side of the field iron piece 26. Similarly, the object to be attracted 18 is separated from the south pole of the permanent magnet 14 by a distance r, so a weak north pole, which is the opposite polarity image magnetic pole, is distributed on one side of the object to be attracted 18. In this state, the attractive force exerted by the permanent magnet 14 on the field iron piece 26 and the attractive force exerted by the permanent magnet 14 on the object to be attracted 18 are in equilibrium.

[0036] In the state shown in Figure 7(c), the permanent magnet 14 is separated from the field iron piece 26 by a distance u, so the S poles, which are the opposite polarity image magnetic poles, are weakly distributed on the field iron pieces 26 on both sides when viewed from the N pole of the permanent magnet 14. Also, since the object to be attracted 18 is separated from the S pole of the permanent magnet 14 by a distance t, the N poles, which are the opposite polarity image magnetic poles, are strongly distributed on the object to be attracted 18.

[0037] In the state shown in Figure 7(d), the field iron piece 26 is separated from the north pole of the permanent magnet 14 by a distance r, so a weak south pole, which is the opposite polarity image magnetic pole, is distributed on one side of the field iron piece 26. Also, the object to be attracted 18 is separated from the south pole of the permanent magnet 14 by a distance r, so a weak north pole, which is the opposite polarity image magnetic pole, is distributed on one side of the object to be attracted 18. In this state, the attractive force that the permanent magnet 14 exerts on the field iron piece 26 and the attractive force that the permanent magnet 14 exerts on the object to be attracted 18 are in equilibrium.

[0038] The attractive force acting on the rotation axis 12 when transitioning from the state shown in Figure 7(a) to (b) will be explained. When the rotation axis 12 rotates even slightly from the state in which the permanent magnet 14 exerts a strong attractive force on the field iron piece 26, the attractive force exerted by the permanent magnet 14 on the field iron piece 26 decreases, and the attractive force exerted by the permanent magnet 14 on the attracted piece 18 increases. At this time, when the rotation axis 12 rotates even slightly from the state in which the permanent magnet 14 exerts the strongest attractive force on the field iron piece 26, the north pole of the reverse-polarity image magnetic pole generated on the attracted piece 18 exerts a force in the direction that pulls the south pole of the permanent magnet 14. As a result, the attractive force exerted by the north pole of the permanent magnet 14 on the field iron piece 26 is canceled out to some extent, and the cogging torque, which is the attractive force acting on the rotation axis 12, decreases. In other words, the maximum cogging torque applied to the rotating shaft 12 does not decrease, but the attractive force that the permanent magnet 14 exerts on the field iron piece 26, which hinders the rotation of the rotating shaft 12, can be reduced by the attractive force acting in the direction of attraction between the attracted piece 18 and the permanent magnet 14. Therefore, the time during which the permanent magnet 14 is strongly attracted to the field iron piece 26 is shortened.

[0039] The attractive force acting on the rotation axis 12 when transitioning from the state in Figure 7(b) to (c) will be explained. If the rotation axis 12 rotates even slightly from the position where the permanent magnet 14 is between the field iron piece 26 and the object to be attracted 18, the distance between the permanent magnet 14 and the object to be attracted 18 decreases, so the attractive force in the direction in which the permanent magnet 14 attracts the object to be attracted 18 increases. Consequently, the distance between the permanent magnet 14 and the field iron piece 26 increases, so the attractive force in the direction in which the permanent magnet 14 attracts the field iron piece 26 decreases.

[0040] The attractive force acting on the rotation axis 12 when transitioning from state 7(c) to state 7(d) will be explained. When the rotation axis 12 rotates even slightly from the state in which the permanent magnet 14 exerts a strong attractive force on the object to be attracted 18, the attractive force that the permanent magnet 14 exerts on the field iron piece 26 increases, and the attractive force that the permanent magnet 14 exerts on the object to be attracted 18 decreases. At this time, when the rotation axis 12 rotates even slightly from the state in which the permanent magnet 14 exerts the strongest attractive force on the object to be attracted 18, the S pole of the reverse-polarity image magnetic pole generated on the field iron piece 26 exerts a force in the direction that pulls the N pole of the permanent magnet 14. As a result, the attractive force that the S pole of the permanent magnet 14 exerts on the object to be attracted 18 is canceled out to some extent, and the cogging torque, which is the attractive force acting on the rotation axis 12, decreases.

[0041] The attractive force acting on the rotation axis 12 when transitioning from state 7(d) to state 7(a) will be explained. If the rotation axis 12 rotates even slightly from the position where the permanent magnet 14 is between the field iron piece 26 and the object to be attracted 18, the distance between the permanent magnet 14 and the field iron piece 26 decreases, so the attractive force in the direction in which the permanent magnet 14 attracts the field iron piece 26 increases. Consequently, the distance between the permanent magnet 14 and the object to be attracted 18 increases, so the attractive force in the direction in which the permanent magnet 14 attracts the object to be attracted 18 decreases.

[0042] Compared to the state without the adsorbed piece 18, the presence of the adsorbed piece 18 increases the number of locations where cogging torque is generated. However, the maximum value of the cogging torque in the direction that inhibits the rotation of the rotating shaft 12 remains the same, but the number of locations where it occurs doubles. In other words, compared to the state without the adsorbed piece 18, the period during which cogging torque is generated is halved.

[0043] Furthermore, when transitioning from Figure 7(a) to (b), the attracted piece 18 positioned between the field iron pieces 26 actively attracts the permanent magnet 14, thereby reducing the attractive force between the permanent magnet 14 and the field iron pieces 26. Also, when transitioning from Figure 7(c) to (d), the field iron pieces 26 positioned between the attracted pieces 18 actively attract the permanent magnet 14, thereby reducing the attractive force between the permanent magnet 14 and the attracted piece 18.

[0044] Therefore, although the maximum cogging torque applied to the rotating shaft 12 does not fluctuate, the time during which the cogging torque strongly affects the rotating shaft 12 is shortened. Combined with the fact that the cogging torque period is halved, this results in the rotating shaft 12 rotating more smoothly.

[0045] This section describes how to reduce cogging torque when using multiple electromotive forces. The electromotive force in this embodiment uses an adsorbed piece and rotates the rotating shaft 12 smoothly by halving the cogging torque period. By changing the positions of the field iron pieces, adsorbed pieces, and permanent magnets of multiple electromotive force devices, the cogging torque can be further reduced. For example, suppose the position of the permanent magnet relative to the field iron piece and the piece to be attracted in one electromotive force device is as shown in Figure 7(a). At this position, the poles of the field iron piece and the permanent magnet are facing each other, so the strongest attractive force is exerted from the permanent magnet 14 to the piece to be attracted 18. Therefore, the cogging torque is large in the vicinity of this position. In that state, if the positions of the field iron piece, the object to be attracted, and the poles of the permanent magnet in other electromotive forces are in a position where the cogging torque is small, the overall cogging torque will be evened out, leading to a reduction in cogging torque. In Figure 7, the areas around (b) and (d) are regions with low cogging torque. Specifically, the cogging torque can be reduced by positioning the poles of the permanent magnets of the electromotive force means so that they are offset from the position opposite the field iron piece and also offset from the position opposite the piece to be attracted.

[0046] By generating electricity using multiple power generation methods, cogging can be reduced, enabling highly efficient power generation. First, let's explain the case where there are two means of generating electricity. There are two electromotive forces: a first electromotive force and a second electromotive force. In both electromotive forces, the positions of the field iron piece and the permanent magnet are the same. Regarding the first power generation means, assume that the field iron piece and the poles of the permanent magnet are in opposing positions, as shown in Figure 7(a). The rotation angle at this position is set to 0 degrees. This state represents a high cogging torque. In the first electromotive force, the next point where the cogging torque is highest is when the poles of the attracted piece and the permanent magnet face each other (Figure 7(c)). The rotation angle is 22.5 degrees. The angle of the permanent magnet in the second electromotive force is shifted from that of the first electromotive force by 11.25 degrees, which is half of 22.5 degrees. Consequently, when the first electromotive force is in the position shown in Figure 7(a), the second electromotive force is in the position shown in Figure 7(b). Therefore, when the cogging torque of the first electromotive force is large, the cogging torque of the second electromotive force becomes small, and the overall cogging torque can be reduced.

[0047] If there are four electromotive forces, when one electromotive force is in the position shown in Figure 7(a), the next electromotive force will be in the position midway between Figures 7(a) and 7(b), the next electromotive force will be in the position shown in Figure 7(b), and the next electromotive force will be in the position midway between Figures 7(b) and 7(c). The rotation angles will be 0 degrees, 5.625 degrees, 11.25 degrees, and 16.875 degrees, respectively. By doing so, the positions with strong cogging torque are distributed, and the cogging torque can be further reduced. In other words, when multiple electromotive forces are connected to the same rotating shaft, and the position of the pole of the permanent magnet of one electromotive force is opposite the position of the field iron piece, cogging torque can be canceled out by positioning the pole of the permanent magnet of at least one other electromotive force so that it is offset from the position opposite the field iron piece and also offset from the position opposite the piece to be attracted. Furthermore, if there are eight electromotive forces, the cogging torque can be more effectively counteracted by finely adjusting the positions of the permanent magnet poles. The same applies when there are 12 or 16 generating devices. As described above, by using a multiple of four for the number of electromotive forces, cogging torque can be drastically reduced.

[0048] Thus, when the position of the pole of a permanent magnet in one electromotive force is opposite to the field iron piece, cogging torque can be reduced by shifting the position of the permanent magnet of another electromotive force to a position that divides the angle between the position of the permanent magnet's pole and the position of the piece to be attracted into equal intervals. In this embodiment, when the angle between the position of the permanent magnet pole and the opposing position on the field iron piece is defined as a rotation angle of 0 degrees, the position where the permanent magnet pole faces the piece to be attracted is at a rotation angle of 22.5 degrees. Therefore, by shifting the position of the permanent magnet so as to equally divide the space between these two positions, the cogging torque can be reduced overall. Therefore, even if the number of electromotive force devices is odd, cogging torque can be reduced by shifting the position of the permanent magnets to a position that divides the number of magnets equally. For example, if there are three electromotive force devices, the cogging torque can be reduced by setting the rotation angles to 0 degrees, 7.5 degrees, and 15 degrees. Similarly, if there are five or seven devices, the cogging torque can be reduced by adjusting them to the same positions. Furthermore, naturally, the cogging torque can also be reduced by increasing the number of these components to multiples of odd numbers.

[0049] While this method of generating electricity is extremely efficient, the amount of heat generated by the coil becomes significant when attempting to increase the amount of electricity produced. As the amount of current generated increases, the coil heats up, and this heat degrades the coil's performance. Therefore, the range in which efficient power generation is possible was limited. The primary objective of this invention is to suppress the heat generation of the coil in the electromotive force device.

[0050] The cooling method using a coolant will be explained with reference to Figures 1 through 4. Figure 1 is a schematic cross-sectional view showing an embodiment of a liquid-cooled generator according to the present invention, where (a) is an example in which each stator is covered with insulating coolant when there are multiple electromotive forces, (b) is an example of the structure of a coolant storage container which is a container for filling the stator with coolant, and (c) shows the relationship between the coolant storage container and the stator, with the upper part of the figure being a cross-sectional view of the first yoke portion and the lower part being a cross-sectional view of the second yoke portion. Figure 2 is a schematic cross-sectional view showing a modified example of the liquid-cooled generator according to the present invention, where (a) shows an example in which the entire set of multiple power-generating means is immersed in the coolant, and (b) shows the case in which the rotation axis of the generator is in a vertical direction. Figure 3 is a schematic cross-sectional view showing a modified example of the liquid-cooled generator according to the present invention, where (a) shows an example in which the entire generator is covered with a sealed waterproof container and the outside is filled with coolant, and (b) shows an example in which the shape of the sealed container is shaped to match the coil and magnet. Figure 4 is a schematic cross-sectional view showing a modified example of the liquid-cooled generator according to the present invention. (a) shows an example in which a portion of the metal plate is exposed from the container and the space between the metal plate and the container is filled with a sealant, etc., and (b) shows an example in which an O-ring is placed between the metal plate and the container. In both (a) and (b), the upper part of the figure is a cross-sectional view of the first yoke portion, and the lower part is a cross-sectional view of the second yoke portion. (c) shows an example in which only the coil excluding the metal plate is immersed in the coolant, and (d) shows an example of its implementation.

[0051] The electromotive force 10 in this embodiment is a power generation means with extremely low cogging torque. However, when attempting to generate a large amount of power by high-speed rotation, so-called Joule heating occurs. When the coil becomes hot due to Joule heating, the resistance of the coil increases, making it difficult for current to flow. Also, the magnetic force of the permanent magnet decreases when it becomes hot. As a result, the power generation efficiency of the electromotive force 10 decreases. Therefore, it is conceivable to cool the power generation means 10. As a cooling method, air cooling, water cooling, etc., are possible, but considering the cooling efficiency, immersion cooling, in which the power generation means 10 is placed in a cooling liquid, is preferred. Immersion cooling involves immersing a device, including an electrical circuit, in an insulating coolant. In this invention, the heat generated by the coil can be directly discharged into the coolant, thus enabling highly efficient cooling. As a coolant, insulating fluorine-based inert liquids or silicone oil are used.

[0052] The structure that cools the stator 11 by liquid immersion will be explained in accordance with Figure 1. This is the case where the liquid-cooled generator 1 has four power generation means 10. As described above, by making the number of electromotive force devices a multiple of four, cogging torque can be efficiently offset. As described above, the electromotive force means 10 consists of a stator 11 comprising a coil 30, a bobbin 31, a yoke 20 which is a magnetic flux application means, a permanent magnet 14, an attractive force means 19, and a rotating shaft 12. The stator 11 is fixed to the base 39, which also serves as the housing, by the stator holding part 37. The attraction means 19 is similarly fixed to the base 39 by the attraction means holding part 38. Bearings 32 are provided inside the bobbin 31 of the stator 11 and inside the fixed base 36 of the attraction means 19, and the rotating shaft 12 is rotatably supported via the bearings 32. The permanent magnet 14 is fixed to the rotating shaft 12, and the permanent magnet 14 and the rotating shaft 12 rotate as a single unit. During power generation, the stator 11 and the attractive means 19 are fixed to the housing, and the permanent magnet 14 rotates together with the rotation shaft 12. Therefore, even if the area around the coil 30 inside the stator 11, where Joule heat is generated during power generation, is covered with coolant 81, it does not affect the rotation of the generator. Heat from the coil 30 can be released without reducing the efficiency of the generator, and the temperature rise of the coil 30 can be suppressed.

[0053] As an example of implementation, as shown in Figure 1(a), each stator 11 is surrounded by a coolant storage container 50, and coolant 81 is stored in each coolant storage container 50, and the coil 30 is directly cooled by the coolant 81. The cooling section consists of a plurality of coolant storage containers 50, a heat exchanger 80, and piping 43 connecting the coolant storage containers 50 and the heat exchanger 80. The coolant storage container 50 is a part that stores coolant 81 for cooling the coil 30 inside the stator 11. The coolant 81 is an insulating liquid, and by so-called immersion cooling, where the coolant 81 is in direct contact with the surface of the coil, the heat from the coil is efficiently conducted to the coolant 81. The coolant storage container 50 is divided into a coil-side half 51 and a permanent magnet-side half 52. As shown in Figure 1(b), the stator 11 is sandwiched between the coil-side half 51 and the permanent magnet-side half 52, and a sealed container structure is formed by welding or the like. The coolant storage container 50 is provided with a hole 53 for the rotating shaft, a hole 54 for the coolant, and a hole 55 for the holding part. The rotating shaft hole 53 is a hole through which the rotating shaft 12 passes through the stator 11. The rotating shaft hole 53 is bonded to the end of the bobbin 31, for example, as shown in Figure 1(c), to maintain the airtightness of the container. The coolant hole 54 is a hole for providing an inlet and outlet for the coolant. To prevent coolant from leaking from around the coolant inlet 41 and coolant outlet 42, the space between the coolant inlet 41, coolant outlet 42 and the coolant hole 54 is sealed tightly with adhesive or the like to prevent leakage. The retaining hole 55 is a hole through which the stator retaining part 37, which holds the stator 11, passes. By fixing the space between the retaining hole 55 and the stator retaining part 37 with adhesive or the like, airtightness is maintained. The permanent magnet side half 52, which is part of the container, is positioned to pass between the stator 11 and the permanent magnet 14. The thickness between the magnetic flux application means of the container and the permanent magnet must be such that the container does not come into contact with the permanent magnet, because the magnetic flux application means side is stationary while the permanent magnet side is rotating. As described above, the gap between the permanent magnet 14 and the first iron piece 22, which is part of the stator 11, is approximately 2 millimeters. Therefore, the thickness of the permanent magnet side half 52 must be 2 mm or less, and considering tolerances, 1 mm or less is preferable. Furthermore, in order to ensure a stable gap, the inner wall of the container may be attached to the first and second iron pieces. By doing so, the gap between the container and the first and second iron pieces, which are the stator side, will be reduced, and the gap on the permanent magnet side, which is the rotating side, will be increased.

[0054] A modified example will be explained using Figure 4 as a guide. Since the gap between the permanent magnet 14 and the first iron piece 22, which is part of the stator 11, is approximately 2 millimeters, the thickness of the coolant storage container 50 must be limited in order to allow a portion of it to pass through that gap, which can be difficult in terms of strength and precision. Therefore, it is conceivable to make the first iron piece 22 and the second iron piece 24 of the magnetic flux application means protrude and expose outside the coolant storage container 50, and to maintain the same positional relationship between the first iron piece 22, the second iron piece 24 and the permanent magnet 14 as in the conventional method. Specifically, as shown in Figures 4(a) and 4(b), holes 56 for the iron pieces are made in the coolant storage container 50 so that the first iron piece 22 and the second iron piece 24 are outside the coolant storage container 50. Furthermore, in order to make the first iron piece 22 and the second iron piece 24 protrude and become exposed, it is necessary to shift the positions of the first iron piece 22 and the second iron piece 24 toward the permanent magnet by the thickness of the container. The magnetic flux application means includes a field iron piece that obtains magnetic flux from a permanent magnet, a coil side plate portion that applies magnetic flux to the coil, and a connecting portion that connects the field iron piece and the coil side plate portion. Therefore, a portion of the long plate 22a and short plate 24a, which are the connecting portion, are deformed to extend towards the permanent magnet side according to the amount of field iron piece exposed. As a result, the positions of the first iron piece 22 and the second iron piece 24 at the end of the connecting portion are shifted towards the permanent magnet side. The long plate 22a, which is the connecting part of the first yoke 20a, can simply be made longer in the direction of the permanent magnet by the amount of displacement of the field iron piece. The short plate 24a, which is the connecting part of the second yoke 20b, is changed from a planar shape to a stepped bend shape. A stepped bend is a stepped shape, as shown in Figure 4(a). By changing the connecting part in this way, the position of the second iron piece 24 can be shifted toward the permanent magnet side relative to the shaft peripheral part 24b, which is the coil side plate part. In this way, the majority of the stator can be housed in the coolant storage container 50 without changing the positional relationship between the first iron piece 22, the second iron piece 24 and the permanent magnet 14. To maintain airtightness around the holes for the metal pieces, Figure 4(a) shows the holes 56 for the metal pieces filled with a sealing portion 57. The sealing portion is a waterproof sealant, etc. Figure 4(b) shows that the liquid waste storage container 50 and the iron piece hole 56 are fixed together with a screw 59 near the iron piece hole 56, and the gap is sealed with an O-ring 58. To ensure a tight seal with the O-ring, a flange is attached to a portion of the iron piece, allowing the O-ring to apply even pressure.

[0055] Figures 4(c) and 4(d) show the case where only the coil 30 and bobbin 31 are covered by the bag-shaped coolant storage container 60. The coil 30 and bobbin 31 are sandwiched between the first yoke 20a and the second yoke 20b. Therefore, only the coil 30 and bobbin 31 are covered by the bag-shaped coolant storage container 60, and the first yoke 20a and the second yoke 20b sandwich them around it. Because it is bag-shaped, the container is easily deformable, and the yokes can be attached in the same way as before. Although the gap between the yoke 20 and the coil 30 is relatively narrow, resulting in a low flow rate of the coolant, the coil can be cooled without changing the structure of the conventional power generation means 10 or the relationship between the gap between the stator 11 and the permanent magnet 14. The coolant enters from the bottom and is discharged from the top.

[0056] The structure in which the entire power generation means 10 is immersed in a cooling liquid and cooled will be explained in accordance with Figure 2. The coolant reservoir 40 is one large reservoir. It completely immerses the inside of the housing containing the power generation means 10. All four electromotive forces 10 and the rotating shaft 12 are filled with coolant 81, and the ends of the rotating shaft 12 are connected to the outside through bearing portions 70, which are holes on the side of the coolant reservoir 40. The coolant 81 is circulated and cooled by the heat exchanger 80. Since liquids are more viscous than air, it is conceivable that the rotation of the permanent magnet 14, which is the rotating part, might be hindered by the coolant. However, since the permanent magnet 14 is cylindrical, there are no protrusions that would create resistance against the coolant during rotation. Therefore, the only load created by immersion is the resistance due to contact between the surface of the permanent magnet 14 and the coolant. Consequently, the load does not increase significantly, and power generation can be performed efficiently. Since the entire power generation means 10 can be cooled, not only the temperature of the coil 30 but also the temperature of the permanent magnet 14 can be stabilized, making it possible to stabilize the power generation efficiency.

[0057] Figure 2(b) shows the rotation shaft 12 oriented vertically. A bearing portion 70 is located at the lower end of the rotation shaft 12. The upper part of the rotation shaft 12 extends outward from the upper hole of the coolant reservoir 40. By keeping the water level of the coolant 81 lower than the upper hole, the upper hole does not need to be waterproofed, and the rotational load can be reduced accordingly.

[0058] Figure 3 shows a structure in which the entire power generation means 10 is covered by a waterproof housing 82, and the area around it is covered by a coolant reservoir 40. Since the coolant does not come into direct contact with the power generation means 10, the coolant does not need to be insulating, and ordinary coolant is sufficient. By extending the tips of the first iron piece 22, the second iron piece 24, etc., and bringing them into contact with the waterproof housing 82, the heat from the coil 30 can be transferred through the iron pieces and released into the cooling liquid. Furthermore, as shown in Figure 3(b), by shaping the waterproof housing 82 to conform to the shape of the yoke 20, the heat from the coil 30 can be transferred through the yoke 20 and released into the coolant.

[0059] Thus, according to this embodiment, the efficiency degradation due to heat generation can be suppressed in a high-efficiency generator, and high-efficiency power generation can be performed at all times.

[0060] Furthermore, by immersing only the stator portion, including the coil, in liquid, the coil can be cooled without affecting its rotation during power generation.

[0061] Furthermore, when the entire power generation device is immersed in liquid, the rotating part is a rotating body relative to the rotating shaft, so power generation can be achieved with minimal resistance to rotation due to the cooling liquid.

[0062] Furthermore, by cooling the generator from the outside of the casing and making a portion of the yoke contact the casing, the heat from the coil can be efficiently released into the coolant. [Explanation of Symbols]

[0063] 1. Liquid-cooled generator 10 Electromotive means 11 Stator 12 Rotation axes 14 Permanent Magnets 18 Piece to be attracted 19 Attraction means 20 Yoke, magnetic flux application means 20a First York 20b Second York 22 First Iron Piece 22a long board 22b Peripheral part of the axis 24. Second Iron Piece 24a short plate 24b Peripheral part of the axis 26 Field magnetite pieces 27 Connecting part 28 Coil side plate section 30 coils 31 bobbins 32 bearings 36 Fixed stand 37 Stator holding part 38 Attraction means holding part 39 Pedestal 40 Coolant reservoir 41 Coolant inlet 42 Coolant outlet 43 Piping 50 Coolant storage container 51 Coil-side half 52 Permanent magnet side half 53 Hole for rotating shaft 54 Cooling water hole 55 Hole for holding part 56 Hole for iron piece 57 Seal part 58 O-rings 59 screws 60 bag-type coolant storage containers 70 Bearing section 80 heat exchanger 81 Coolant 82 Waterproof housing

Claims

1. A permanent magnet in which magnetic poles are arranged radially around a rotation axis and alternately along the circumferential direction, A coil made by winding conductive wire around an electrically insulated bobbin, A magnetic flux applying means, composed of multiple metal pieces, applies the magnetic flux generated from the permanent magnet to the coil, An attractive force means comprising a plurality of attractable pieces arranged radially around the axis of rotation, which are magnetized by the permanent magnet and fixed to a non-magnetic base, Includes a power generation means configured by, The permanent magnet rotates with the axis of rotation, the magnetic flux application means is positioned on one broad surface side of the permanent magnet, and the attractive force means is positioned on the other broad surface side of the permanent magnet. The magnetic flux application means comprises a first yoke for guiding the magnetic flux to the pole of the coil that is farther from the permanent magnet, and a second yoke for guiding the magnetic flux to the pole of the coil that is closer to the permanent magnet. The first yoke and the second yoke are each provided with a plurality of field iron pieces for obtaining magnetic flux from the permanent magnet. The number of field iron pieces and the number of pieces to be attracted are equal, and the field iron pieces and the pieces to be attracted are arranged at equal angles with respect to the axis of rotation, and the pieces to be attracted are positioned at an intermediate angle between adjacent field iron pieces, so that the field iron pieces and the pieces to be attracted are offset by equal angles. Multiple of these electromotive forces are connected to the same rotating shaft, and in order to cancel out cogging torque, when the position of the pole of the permanent magnet of one electromotive force is opposite the position of the field iron piece, the position of the pole of the permanent magnet of at least one other electromotive force is offset from the position opposite the field iron piece and also offset from the position opposite the piece to be attracted. The coil and the magnetic flux application means are stators, The cooling unit comprises a coolant storage container, a heat exchanger, and piping connecting the coolant storage container and the heat exchanger. The cooling section is filled with a coolant consisting of an insulating liquid. The coolant circulates through a closed space consisting of the coolant storage container, the heat exchanger, and the piping, and is cooled by the heat exchanger. A liquid-cooled generator characterized in that the coolant storage container covers at least the coil, and the coil is immersed and cooled by the coolant.

2. The coolant is stored in a container corresponding to each of the stators. A portion of the container passes between the magnetic flux application means and the permanent magnet, The liquid-cooled generator according to claim 1, characterized in that the thickness between the magnetic flux applying means and the permanent magnet in the container is such that the container does not come into contact with the permanent magnet.

3. The coolant is stored in a container corresponding to each of the stators. The magnetic flux application means comprises a field iron piece that obtains magnetic flux from the permanent magnet, a coil side plate portion that applies magnetic flux to the coil, and a connecting portion that connects the field iron piece and the coil side plate portion. The container has a hole for exposing the field iron piece to the outside of the container. The field iron piece is exposed outside the container, The liquid-cooled generator according to claim 1, characterized in that a part of the connecting portion deforms toward the permanent magnet side in accordance with the amount of exposure of the field iron piece.

4. The rotating part is the cylindrical permanent magnet whose axis is in the axial direction of the rotation shaft, The liquid-cooled generator according to claim 1, characterized in that the entire power generation means is immersed in liquid cooling.

5. The outside of the housing on which the power-generating means is mounted is cooled by liquid immersion. The liquid-cooled generator according to claim 1, characterized in that a portion of the metal piece is in contact with the housing.

6. The liquid-cooled generator according to any one of claims 1 to 5, characterized in that the number of the power-generating means is a multiple of 4.

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