JP7509028B2 - Wave front float power generation device - Google Patents

Description

The present invention relates to a buoy that floats on the water and is equipped with an energy harvesting device, and in particular to a wave surface float power generation device that utilizes the change in the inclination of the buoy due to the movement of waves.

Patent Document 1 describes an example of a power generation device that uses electromagnetic induction, in which a magnet is mounted on the inner surface of a cylindrical coil so that it can roll or slide. In this power generation device, a magnet is placed on the inner surface of a cylindrical coil wound around a cylinder, and the internal magnet rolls inside the coil by tilting the cylindrical coil, generating electricity. Patent Document 1 suggests that when this power generation device is attached to a tree or the like, it generates electricity in response to the tree's swaying caused by wind force, and when the housing of the power generation device is floated on the sea, it generates electricity from wave motion.

Japanese Patent Application Laid-Open No. 10-42540

However, the technology disclosed in Patent Document 1 has the problem that because it is a cylindrical coil, it can only generate electricity when there is a tilt (height difference) in the core direction.

The present invention was developed in consideration of the above-mentioned problems with the conventional technology, and aims to provide a wave surface float power generation device that can generate sufficient power even with a slight difference in elevation like ripples.

The wave front float power generation device of the present invention is characterized by having a buoy housing with a closed space inside, a shaft arranged in the space, a rotor arranged in the space and fixed to the shaft, having a center of gravity at a position off the rotation axis of the shaft and rotatable around the rotation axis of the shaft, a repulsive magnetic bearing provided on the housing and the rotor for rotatably supporting the rotor, and a dynamo fixed to the housing that is driven by the rotation of the rotor via the shaft to generate electricity.

The wave float power generation device of the present invention has the advantage that sufficient power generation can be obtained even with ripple-like wave sway or slight elevation differences due to the bias in the weight distribution.

1 is a perspective view conceptually showing a wave front float power generation device according to a first embodiment of the present invention; FIG. 2 is a partial cross-sectional view illustrating the inside of the wave front float power generation device, partially cut along the line xx in FIG. 1 . 3 is a diagram illustrating the operation of the wave front float power generation device according to the first embodiment; FIG. FIG. 4 is a diagram illustrating the operation of the wave front float power generation device according to the first embodiment when it is inverted. FIG. 4 is a cross-sectional view conceptually showing a wave front float power generation device according to a second embodiment of the present invention. FIG. 11 is a perspective view illustrating a rotating plate in a wave front float power generation device according to a second embodiment. FIG. 11 is a perspective view illustrating a modified example of a rotating plate in the wave front float power generation device of the second embodiment.

Below, we will explain the wave front float power generation device of the embodiment of the present invention with reference to the drawings. In the embodiment, components that have substantially the same functions and configurations are assigned the same reference numerals and duplicate explanations are omitted.

(Description of configuration)
Fig. 1 is a perspective view conceptually showing a wave surface float power generation device 10, which is a buoy floating on the sea according to a first embodiment of the present invention. Fig. 2 is a partial cross-sectional view partially cut along the line xx in Fig. 1 to explain the inside of the wave surface float power generation device 10.

The wave front float power generation device 10 comprises a closed housing (hereinafter also referred to as a buoy) BUOY as a floating body, a dynamo 11 as a generator arranged in its sealed internal space SP, a shaft SF that drives the dynamo, and a rotating plate 12 (rotating body) that rotates the shaft. The wave front float power generation device 10 also comprises an electronic device 15 having a load circuit electrically connected to the dynamo 11 and supplied with power. The electronic device 15 is an electronic device that uses the electricity generated by the dynamo 11, and has, for example, a function of rectifying the electricity from the dynamo 11 and a function of storing electricity. The electronic device 15 does not have to be inside the wave front float power generation device 10, but may be mounted externally as long as it is supplied with power.

The buoy BUOY has a closed space SP inside. The buoy BUOY's housing material can be made of water-resistant synthetic resin, glass, etc., to block the effects of water or air and allow electromagnetic waves to pass from the outside to the inside. The external shape of the buoy BUOY is not limited to a cylindrical shape, and the floating body FL and ballast can be attached to the exterior of the buoy body, and the overall external shape can be an ellipse, a circle (sphere), a cube/rectangle, etc.

The dynamo 11, which generates electricity by rotating its own drive shaft, is driven by the rotation of the rotating plate 12 via the shaft SF, which is integral with the drive shaft and is coaxial with it, to generate electricity. The outer circumference of the dynamo 11 is fixed to the buoy with synthetic resin or the like so that the dynamo 11 does not rotate together with the drive shaft when it rotates.

The rotating plate 12 is a disk placed in the space SP, and the center of the disk is fixed to the shaft SF. The rotating plate 12 has its center of gravity at a position that is offset from the central axis of rotation (also simply called the rotation axis) of the shaft SF. The rotating plate 12, whose center of gravity is offset from the central axis of rotation, is capable of rotating together with the shaft SF in a plane perpendicular to the shaft SF. The rotating plate 12 rotates together with the shaft SF and can drive the dynamo 11 attached to the shaft SF.

The rotating plate 12 is, for example, a cylindrical magnetic disk (first permanent magnet) magnetized in the direction of the rotation axis of the shaft SF. For example, a ferrite magnet is used for the rotating plate 12.

The rotating plate 12 is provided with a weight 13 that is heavier than the rest of the rotating plate at a portion of its periphery near the outer periphery, away from the axis of rotation of the fixed shaft SF, so that the center of gravity is biased from the axis of rotation of the shaft to the weight. The weight 13 is made of a non-magnetic material such as austenitic stainless steel, high manganese steel, or high nickel alloy that has a higher specific gravity than the other parts of the rotating plate (ferrite), making the rotating plate 12 partially heavy. The weight 13 is installed inside the rotating plate 12 so as not to change its external shape.

The repulsive magnetic bearing PMB is a magnet assembly in which magnet disks 14b, 14c and magnet cylinder 14d, each with approximately the same radius, are arranged with their centers coaxially with the rotation axis of shaft SF, and are embedded in the buoy so as to define a closed space SP between them. In other words, the outer periphery of the repulsive magnetic bearing PMB is fixed to the buoy with synthetic resin or the like so that its position does not move due to the inclination of the buoy. In the space SP of the buoy, the rotating plate 12 and the repulsive magnetic bearing PMB are arranged concentrically and rotationally symmetrically around the rotation axis of shaft SF.

The magnet disks 14b, 14c and the magnet cylinder 14d are magnets (second permanent magnets) magnetized in the direction of the rotation axis of the shaft SF. Examples of the magnetic material of the second permanent magnet include ferrite magnets and neodymium magnets. An opening for the shaft SF is provided in the center of the magnet disk 14c on the dynamo 14 side. The rotating plate 12 is sandwiched between the pair of magnet disks 14b, 14c of the second permanent magnet in the direction of the rotation axis of the shaft SF, and is arranged so as to be surrounded by the magnet cylinder 14d of the second permanent magnet in the direction perpendicular to the rotation axis of the shaft SF.

The repulsive magnetic bearing PMB has a first permanent magnet 12a provided on the outer surface of the rotating plate 12 and second permanent magnets 14b, 14c fixed to the buoy and arranged opposite the first permanent magnet 12a, with the same poles of the first permanent magnet 12a and the second permanent magnets 14b, 14c facing each other. In other words, the repulsive magnetic bearing PMB (second permanent magnet) surrounds the rotating plate 12 (first permanent magnet) and is installed so that the same poles face the magnetic poles of the rotating plate 12, and by floating the rotating plate 12 by the repulsive force, the rotating plate 12 is supported rotatably in a spaced-apart state and no load other than rotation is applied to the drive shaft of the dynamo 11. The gap between the rotating plate 12 and the inner surface of each permanent magnet can be set to about several mm to cm so that a repulsive force can be obtained.

The rotating plate 12 has a weight distribution that is biased in one part of its radius, which is heavier than the other parts. In other words, the rotating plate 12 has a center of gravity that is biased from the central axis of rotation, so that it can rotate easily in response to any inclination of the buoy.

In this way, a part of the rotating plate 12 (weight 13) is heavier than the other parts, and depending on the inclination of the buoy, that part of the rotating plate 12 can always rotate to the lowest position of the buoy. In other words, inside the buoy, the rotating plate 12 is lighter than the weight of the entire wave front float power generation device, so it can rotate either clockwise or counterclockwise depending on the inclination of the buoy. The drive shaft of the dynamo 11 has a rotation direction sensor (not shown), and is configured to control the level of the output voltage depending on the output signal of the rotation direction sensor.

(Explanation of operation)
Fig. 3 is a diagram explaining the operation of the wave surface float power generation device 10 of this embodiment. Fig. 3(A) shows the attitude of the wave surface float power generation device 10 when placed on the sea surface where there are almost no waves and it is almost still, and Fig. 3(B) shows the attitude of the wave surface float power generation device 10 tilted by the movement of waves on the sea surface.

When the wave surface float power generation device 10 is placed on the sea, due to the movement of the waves on the sea surface, the wave surface float power generation device does not maintain an absolute horizontal state, but will always be higher at one point and in many cases the opposite side will be lower. And these higher and lower points are constantly changing in accordance with the movement of the waves.

Therefore, when the waves (not shown) change from the state shown in Figure 3(A), the tilt of the buoy BUOY changes to the state shown in Figure 3(B). As shown in Figure 3(B), when the buoy BUOY tilts, the dynamo 11 and the repulsive magnetic bearing PMB fixed to the buoy BUOY tilt. When the repulsive magnetic bearing PMB tilts, the rotating plate 12 also tilts due to the repulsive force. Because the dynamo 11 and the repulsive magnetic bearing PMB are fixed to the buoy BUOY, the positional relationship between the drive shaft (shaft SF) of the dynamo 11 and the rotating plate 12 does not change when the buoy BUOY tilts, and because the rotating plate 12 is floated by the repulsive force with the repulsive magnetic bearing PMB, no load is applied to the drive shaft of the dynamo 11.

At this time, if the weight 13 of the rotating plate 12 in the wave front float power generation device 10 is not at its lowest point (see FIG. 3(A)), the weight 13 that is not at its lowest point will start to move toward its lowest point as shown by the arrow in FIG. 3(B), causing the rotating plate 12 to rotate. In this way, when the inclination of the buoy BUOY changes, the weight 13 moves toward the lowest point of the buoy BUOY. Because the weight 13 is attached to the rotating plate 12, the movement of the weight 13 causes the rotating plate 12 to rotate together with the shaft SF, and the dynamo 11 generates electricity.

Figure 4 is a diagram that explains the operation of the wave surface float power generation device 10 of this embodiment when it is inverted relative to the sea surface. Figure 4(A) shows the attitude of the inverted wave surface float power generation device 10 when placed on the sea surface where there are almost no waves and it is almost still, and Figure 4(B) shows the attitude of the inverted wave surface float power generation device 10 tilted due to the movement of waves on the sea surface.

When only the weight of the wave front float power generation device 10 is considered, the weight of the repulsive magnetic bearing PMB is sufficiently large compared to the rest, so the buoy BUOY is inverted as shown in Figure 4 (A). Since the dynamo 11 and the repulsive magnetic bearing PMB are fixed to the buoy BUOY, the positional relationship between the drive shaft of the dynamo 11 and the rotating plate 12 does not change even if the buoy BUOY is inverted, and since the rotating plate 12 is floated by the repulsive force with the repulsive magnetic bearing PMB, no load is applied to the drive shaft of the dynamo 11.

When the wave surface float power generation device 10 tilts due to ocean waves as shown in Figure 4 (B), if the weight 13 of the rotating plate 12 of the wave surface float power generation device 10 is not at its lowest point, the weight 13 that is not at its lowest point will start to move toward its lowest point as shown by the arrow in Figure 4 (B), causing the rotating plate 12 to rotate. In this way, when the tilt of the buoy BUOY changes, the weight 13 moves toward the lowest point of the buoy BUOY. Because the weight 13 is attached to the rotating plate 12, the movement of the weight 13 causes the rotating plate 12 to rotate together with the shaft SF, and the dynamo 11 generates electricity.

(Explanation of effects)
As described above, according to the first embodiment, the repulsive magnetic bearing PMB allows the rotating plate 12 to rotate smoothly, so that even a slight difference in height, such as ripples, can be used to rotate the dynamo by utilizing the change in inclination, and sufficient power can be generated by the dynamo 11 simply by floating it on the sea.

In conventional technology, there were directions in which power could not be generated depending on the angle at which the wave front float power generation device was tilted, but in this embodiment, power can be generated regardless of the tilt direction. In conventional technology, loss occurred due to friction when generating power, but in this embodiment, loss due to the rotation of the rotating plate can be eliminated.

Figure 5 is a cross-sectional view conceptually showing a wave front float power generation device 10 of the second embodiment. This embodiment is the same as the first embodiment, except that instead of the rotating plate 12 in the first embodiment, in which a weight body 13 heavier than the surrounding area is provided at a position off the rotation axis of the shaft SF, a biased center of gravity rotating plate 122 is used, in which a lightweight body 133 with a specific gravity lighter than the rotating plate is provided at a position other than a part of the periphery near the outer periphery off the rotation axis of the shaft SF while keeping the magnetic pole faces of both outer surfaces parallel.

The rotating plate 122 in this embodiment is shown in the perspective view of Figure 6. For example, a starting material for a circular rotating plate made of a ferrite magnet is left with a rotating plate connection part 122C that connects in the axial direction at a part of the periphery near the outer periphery that is off the rotation axis of the fixed shaft SF, and the magnetic pole faces on both outer surfaces of the surrounding rotating plate part are hollowed out while keeping them parallel, and a lightweight body 133 (for example, a non-magnetic body such as synthetic resin) with a specific gravity lighter than that of the rolling plate is filled in and set in place, thereby obtaining a rotating plate 122 whose center of gravity is biased from the rotation axis of the shaft to the rotating plate connection part 122C.

Furthermore, although not shown, the space can be utilized as a light body 133, i.e., as long as the strength can be maintained, a biased weight distribution can be formed even if the rotating plate 122 is missing a part of the rotating plate 12 except for the rotating plate connection part 122C while keeping the magnetic pole faces on both outer surfaces parallel.

This embodiment achieves the effects of the first embodiment as well as reducing the weight of the device.

As a modified example, an example of a rotating plate in the wave front float power generation device of the second embodiment is described with reference to the perspective view of Figure 7. The rotating plate 122 of this modified example is the same as the rotating plate shown in Figure 6, except that a weight 13 heavier than the other rotating plate parts is provided inside the rotating plate connection part 122C. In this way, by combining the first embodiment with the second embodiment, the center of gravity is further shifted from the rotation axis of the shaft SF to the rotating plate connection part 122C, so that the efficiency of rotation of the rotating plate when the buoy tilts can be increased.

10 Wave front float power generation device 11 Dynamo 12 Rotating plate 13 Cone body 12a First permanent magnet 14b, 14c, 14d Second permanent magnet 15 Electronic device BUOY Buoy PMB Repulsive type magnetic bearing SF Shaft

Claims (3)

A buoy housing having an internally enclosed space;
a dynamo fixed inside the housing;
a shaft that drives the dynamo ;
a rotating plate which is a cylindrical magnetic disk of a first permanent magnet whose center of rotation is fixed to the shaft , whose center of gravity is located at a position offset from the rotation axis of the shaft, and which is magnetized in the extension direction of the rotation axis of the shaft ;
a pair of magnet disks, which are second permanent magnets that are spaced apart from both sides of the rotating plate in the extension direction of the rotation axis of the shaft, sandwich the rotating plate, and are magnetized in the extension direction of the rotation axis of the shaft, the pair of magnet disks being fixed inside the housing so that the same poles as the first permanent magnets of the rotating plate face each other;
a magnet cylinder, which is a second permanent magnet that surrounds the rotating plate and is spaced apart from the circumferential outer surface of the rotating plate in a direction perpendicular to the rotation axis of the shaft and is magnetized in the extension direction of the rotation axis of the shaft, the magnet cylinder being fixed inside the housing so that the same poles as the first permanent magnet of the rotating plate face each other at openings at both ends;
having
A wave front float power generation device characterized in that the dynamo is driven via the shaft by the rotation of the rotating plate to generate power. The wave front float power generation device described in claim 1, characterized in that a weight that is heavier than the surrounding area is provided at a part of the rotating plate that is offset from the rotation axis of the shaft, thereby displacing the center of gravity from the rotation axis of the shaft. The wave front float power generation device described in claim 1, characterized in that a lightweight body having a lower specific gravity than the surrounding area is provided at a part of the rotating plate offset from the rotation axis of the shaft, thereby displacing the center of gravity from the rotation axis of the shaft.

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