Wave power generation unit and wave power generation system

Abstract

To provide a wave power generation unit and a wave power generation system having a form suitable for performing wave power generation in waters such as waters where the influence of the impact force of the breaking wave is small, that is, in the offing. 【Solution means】 The wave receiving bucket 32P1 at the first submerged position P1 has its wave receiving surface 32b facing downward when the floating body 2 floats on the water surface 100, and an upward relative water flow 103a acts toward this wave receiving surface 32b, so that the wave receiving bucket 32P1 at the first position P1 is relatively pushed upward and the rotating main body 31 and the rotating shaft 33 are rotated in the forward rotation direction (the direction of the solid arrow in FIG. 5). Therefore, the wave receiving bucket 32P1 at the first submerged position P1 is suitable for converting the upward relative water flow 103a that applies an external force into the rotational motion of the rotating shaft 33 of the wave receiving rotating body 3.

Description

Technical Field

[0001] The present invention relates to a wave power generation unit and a wave power generation system capable of generating electricity by using the power of waves generated offshore.

Background Art

[0002] Conventionally, various proposals have been made for wave power generation systems that generate electricity using wave power and wave power generation units used in such systems. For example, in Patent Document 1, a wave energy conversion system using a turbine equipped with rotatable blades appropriately designed to convert the flow of water in breaking waves generated along the coast into electric power and a wave energy conversion unit used in this system have been proposed.

[0003] This system and unit use a plurality of wave energy conversion units installed on or near the coastline to receive the water flow caused by ocean waves approaching the coastline. Note that ocean waves are waves that occur on the ocean surface that have developed and grown gradually while absorbing energy from the wind, starting from small wind waves (ripples) generated by the friction of the wind blowing on the water surface.

[0004] Here, according to the description of Patent Document 1, the wave energy conversion unit is installed at a location where the average water depth is about 1 to 5 m near the coast, and the waves along the coastline are said to generate fast horizontal water flows that repeatedly move in the direction towards the land and in the opposite direction. Note that the coast refers to the boundary area between the sea and the land, and the coastline refers to the boundary line between the sea and the land.

[0005] According to the ocean wave theory described in Patent Document 1, when ocean waves approach the coast, wave energy is concentrated near the surface because the boundary between the water surface and the seabed slope narrows. As a result, the wave height increases continuously and finally reaches a critical point and breaks. Immediately before the wave breaks, in a typical wave state (height of several meters), the water flow velocity reaches about 5 - 10 m / s in the direction facing the coast. By placing a rotating turbine in this water flow, electricity can be generated.

[0006] Here, waves that approach the coast and break like this are called "breaking waves". Such breaking waves mean that as waves enter from the deep sea area offshore into the shallow sea area, the water depth becomes shallower and the wave height increases. The wave crest becomes sharp, the wave trough becomes flat, and finally, when the wave height approaches the water depth, the wave breaks in its advancing direction.

[0007] Also, the sea area from the position on the offshore side where such breaking waves begin to occur to the shoreline is called the "breaking wave zone". Since the energy generated by breaking waves in this breaking wave zone is extremely large, many power generation systems using the horizontal flow of these breaking waves have been proposed in addition to those described in Patent Document 1.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, when a breaking wave occurs at or near the coastline, it generates a large impact force (also referred to as impact breaking wave force or impact breaking wave pressure) when it collides with an object, and such collisions are frequent. Therefore, installing a wave power generation unit such as such a wave energy conversion unit has a problem that this unit may be damaged or malfunction due to the impact force of the breaking wave.

[0010] On the other hand, ocean waves occurring offshore, for example, deep water waves, result in circular motion where fluid particles of seawater move in a circular pattern. Thus, water movement and flow occur not only in the horizontal direction but also in the vertical direction, which is different from the behavior of coastal waters or waters near the coast such as the surf zone where the horizontal water movement is the main component. In other words, deep water waves are external gravity waves that occur on the water surface where the water depth is sufficiently deep compared to the wavelength.

[0011] Theoretically, in the case of the generation area of deep water waves where the water depth h is very large compared to the wavelength λ of the wave (h ≫ λ), the fluid particles in the deep water waves perform circular motion. In the case of the generation area of shallow water waves where the water depth h is smaller than the wavelength λ of the wave (h < λ), the fluid particles in the shallow water waves perform an extremely flattened elliptical motion, and the entire water from the water surface to the bottom can be approximated as a state where the vertical motion is extremely small, that is, it moves almost only in the horizontal direction.

[0012] On the other hand, as the water depth h approaches infinity compared to the wavelength λ of the wave, the motion of the fluid particles in the wave changes from an extremely flattened elliptical motion to an elliptical motion where the vertical minor axis gradually becomes larger than the horizontal major axis, becoming closer to circular motion. As a result, the motion involves vertical movement, which is different from the behavior of moving only in the horizontal direction. That is, ocean waves offshore are not those where water moves only in the horizontal direction but also in the vertical direction.

[0013] When waves approach the shore from offshore, the change in water depth caused by the slope of the bottom of the water causes the wavelength of the wave to shorten while the wave height increases. This change in waveform due to the change in water depth is called "shallow water transformation." After this "shallow water transformation," the wave finally breaks in the direction of its travel and breaks, causing the wave breakers mentioned above. Generally, this "shallow water transformation" occurs in water areas where the water depth h is shallower than half the wave wavelength λ (h<λ / 2), and it is said that the phenomenon of breaking also occurs as a secondary effect.

[0014] Therefore, in this application, for the sake of convenience, we define "offshore" as waters deeper than the area where "shallow water deformation" occurs, and propose a wave power generation unit that can generate electricity using wave power in such offshore areas, and a wave power generation system that uses this wave power generation unit.

[0015] In other words, the present invention has been made to solve the above-mentioned problems, and proposes a wave power generation unit and wave power generation system having a configuration suitable for performing wave power generation in waters such as marine areas where the impact of breaking wave impact forces is small, i.e., offshore. As a result, the effects of breaking wave impact forces caused by the wave breaking phenomenon can be avoided, and damage to the wave power generation unit due to such breaking wave impact forces can also be reduced.

[0016] In this application, the ocean is mainly described as an example of the water area to which the present invention can be applied, but the water area to which the present invention can be applied is not necessarily limited to the ocean, and may include, for example, lakes, marshes, rivers, and other water areas where surface waves occur similar to the ocean. [Means for solving the problem]

[0017] To achieve this object, the wave power generation unit of the first invention is for a wave power generation system that generates electricity using surface waves generated on the sea surface offshore. It includes a floating body that can float on the sea surface via buoyancy above the sea surface where the surface waves occur, and can sway on the sea surface and become swayable by moving in each axial direction of the space-fixed coordinate system and rotating around each axis in response to the surface waves; a rotating main body portion rotatably supported by the floating body via a rotating shaft and integrated with the rotating shaft; a plurality of wave receiving buckets provided on the entire outer periphery of the rotating main body portion; and a wave receiving rotating body formed in a water wheel shape having a wave receiving surface formed in each wave receiving bucket to receive the surface waves, and using the rotation of the rotating shaft to rotate the rotor portion of the generator. In the state where the floating body floats on the sea surface, at least a part of the plurality of wave receiving buckets of the wave receiving rotating body is in a state of being submerged in water, and the wave receiving buckets in the submerged part receive the relative water flow generated in the water at a first position where the wave receiving surface faces downward and at a second position rotated around the axis of the rotating shaft from the first position where the wave receiving surface faces sideways, and apply a rotational force to the rotating main body portion by receiving the relative water flow on the wave receiving surface.

[0018] Here, the space-fixed coordinate system is a three-dimensional orthogonal coordinate system XYZ with the origin fixed in space such as the ground surface, and is also referred to as a space coordinate system or a ground surface-fixed coordinate system.

[0019] In addition, in the wave receiving rotating body, the rotating shaft is the rotating shaft of the entire wave receiving rotating body and is also the rotating shaft of the rotating main body portion of the wave receiving rotating body. Also, the axis of this rotating shaft (the center of the axis) is also the center of the circular orbit of the plurality of wave receiving buckets and the rotation center of the rotating main body portion. Also, the generator is a device that converts the rotation of its rotor portion into electrical energy.

[0020] In addition, "upward" refers to the vertically upward direction (the direction opposite to the direction of the earth's gravity, the positive direction of the Z axis of the space-fixed coordinate system), "downward" refers to the vertically downward direction (the direction of the earth's gravity, the negative direction of the Z axis of the space-fixed coordinate system), and "sideways" refers to the horizontal direction (the direction perpendicular to the direction of the earth's gravity, the direction parallel to the XY plane of the space-fixed coordinate system).

[0021] In addition, when the receiving bucket at the second position rotates approximately 90° in the forward rotation direction from the receiving rotating body, it will rotate and move to the first position. In other words, the receiving bucket at the first position corresponds to the state where the receiving bucket at the second position has rotated and moved approximately 90° in the forward rotation direction around the axis of the rotation axis of the receiving rotating body.

[0022] In addition, the relative water flow generated in water refers to the relative water flow generated in water by the cooperation of the movement of the surface wave and the swaying of the floating body caused by the surface wave.

[0023] According to this first invention's buoyancy power generation system, the floating body floats on the water surface of a water area such as the sea surface through buoyancy. This floating body receives the movement of the surface wave (including swaying) on the water surface and sways. The swaying of this floating body is the movement in the directions of the X-axis, Y-axis, and Z-axis of the space-fixed coordinate system and the rotation around each of these coordinate axes, and it is a movement in which one or more of each movement and each rotation are combined.

[0024] Such swaying of the floating body includes swaying in the X-axis direction (front-back sway (surge, surging)), swaying in the Y-axis direction (left-right sway (sway, swaying)), swaying in the Z-axis direction (up-down sway (heave, heaving)), rotational sway around the X-axis (roll, rolling), rotational sway around the Y-axis (pitch, pitching), and rotational sway around the Z-axis (yaw, yawing).

[0025] Here, in the state where the floating body floats on a horizontal water surface, at least a part of the plurality of receiving buckets of the receiving rotating body is in a state of being submerged in water, and the receiving bucket in this submerged part receives the relative water flow generated in water on its receiving surface, so that this relative water flow acts as an external force to push the receiving bucket and rotate the rotation main body part in the forward rotation direction together with the rotation axis.

[0026] When the rotating main body and the rotating shaft rotate in the forward rotation direction, the plurality of wave receiving buckets on the outer periphery of the rotating main body will perform circular motion along a circular orbit centered on the rotating shaft as the rotating main body rotates, and each wave receiving bucket will repeatedly pass through the first position in sequence and also perform a series of movements of repeatedly passing through the second position.

[0027] When the rotating main body is rotated by the circular motion of the plurality of wave receiving buckets and the rotating shaft is rotated integrally with the rotating main body, the rotor part, which is the rotating body of the generator, is rotated by using the rotation of this rotating shaft. This generator is mounted on a floating body, and when the rotating shaft of the wave receiving rotating body is rotated, the rotor part is rotated by using the rotational force of this rotating shaft to generate electricity.

[0028] Here, the wave receiving bucket at the submerged first position has its wave receiving surface facing downward when the floating body is floating on the water surface, and when an upward relative water flow acts on this wave receiving surface, the wave receiving bucket at the first position is relatively pushed upward and the rotating main body and the rotating shaft are rotated in the forward rotation direction.

[0029] Therefore, the wave receiving bucket at the submerged first position is suitable for converting not a relative water flow that acts an external force in the lateral direction, but particularly a relative water flow that acts an external force upward into the rotational motion of the rotating shaft of the wave receiving rotating body.

[0030] For example, when assuming the direction parallel to and perpendicular to the rotating shaft of the wave receiving rotating body as the front-rear direction of the floating body, when the floating body sways such as rolling (see Fig. 5(c)), pitching (see Figs. 5(a) and 5(b)), or heaving (see Figs. 5(a) and 5(b)) in response to surface waves, the relative water flow generated in the water is likely to act as an upward relative flow with respect to the wave receiving surface of the wave receiving bucket at the first position, and it is speculated that the rotating main body and the rotating shaft are easily rotated forward through the external force received by the wave receiving bucket at such a first position.

[0031] On the other hand, the receiving bucket at the submerged second position has its receiving surface facing sideways when the floating body is floating on the water surface, and a relative water flow in the lateral direction acts on this receiving surface, so that the receiving bucket at the second position is relatively pushed and moved laterally and the rotating main body and the rotating shaft are rotated in the forward rotation direction.

[0032] Therefore, the receiving bucket at the submerged second position is suitable for converting a relative water flow that acts as an external force in the lateral direction, such as in the front-back, left-right directions, rather than a relative water flow that moves upward and acts as an external force, into the rotational movement of the rotating shaft of the receiving rotating body.

[0033] For example, when assuming that the direction parallel to and perpendicular to the rotating shaft of the receiving rotating body is the front-back direction of the floating body, when the floating body receiving the surface wave sways such as pitching (surging) and yawing (yawing), the relative water flow generated in the water becomes a relative water flow in the lateral direction with respect to the receiving surface of the receiving bucket at the second position and is likely to act, and it is presumed that the rotating main body and the rotating shaft are easily rotated forward through the external force received by the receiving bucket at such a second position.

[0034] In this way, the external forces received by the receiving buckets at the first position and the second position on their receiving surfaces both become rotational forces that rotate the rotating main body in the forward rotation direction. This rotational force is generated when the receiving surfaces of the receiving buckets that have rotated sequentially to the first position and the second position receive the relative water flow in the water as an external force. According to this receiving rotating body, not only the lateral movement in the relative water flow but also the upward movement in the relative water flow can be converted into a driving force for rotating the receiving rotating body.

[0035] In this way, the wave receiving rotating body can convert the movement of the relative water flow into rotational force not only for the wave receiving bucket at the second position but also for the wave receiving bucket at the first position, and use this rotational force to rotate the rotating main body and the rotating shaft to rotate the rotor of the generator for power generation. Therefore, it is completely different from the conventional power generation system that simply converts only the lateral movement of the relative water flow into rotational force for power generation.

[0036] Moreover, when the rotating main body of the wave receiving rotating body starts to rotate in the forward direction, each wave receiving bucket starts to perform circular motion in the forward direction together with the rotating main body around the rotating shaft as it rotates. They come to the first and second positions one after another, are pushed by the movement of the relative water flow, move from the first and second positions to the subsequent positions, and then come to the first and second positions again. By repeating this operation, the rotation of the rotating shaft is maintained, and the rotor of the generator is continuously rotated to continue power generation.

[0037] In particular, since the wave receiving rotating body can be rotated through the wave receiving bucket at the first position, by fixing the floating body in a stationary manner off the shore or the like, power generation can be carried out using the upward movement of the relative water flow to utilize the rotational force of the wave receiving rotating body even in a place where there are no or weak incoming and outgoing waves such as the shore or its vicinity.

[0038] The wave power generation unit of the second invention is the wave power generation unit of the first invention, wherein the plurality of wave receiving buckets are provided on the rotating main body at regular intervals on a pitch circle centered on the axis of the rotating shaft, and include a pointed end portion having a pointed shape facing the forward rotation direction side of the rotating main body, a wave receiving surface facing the opposite direction of the pointed end portion and having a concave shape toward the pointed end portion side, and a pointed outer peripheral surface having a shape in which the outer diameter gradually decreases from the wave receiving surface toward the pointed end portion.

[0039] According to the wave power generation unit of the second invention, in addition to exhibiting the same actions and effects as the wave power generation unit of the first invention, each wave receiving bucket is formed such that its pointed tip and pointed outer peripheral surface face the forward rotation direction side of the rotating main body portion. Therefore, when the wave receiving bucket moves relatively in water as the rotating main body portion rotates, the resistance coefficient can be reduced. By having at least a part of the plurality of wave receiving buckets in a submerged state, the rotational resistance received by the wave receiving rotating body can be reduced, and a decrease in the power generation efficiency of the generator operated by the rotation of the wave receiving rotating body can be suppressed.

[0040] The wave power generation unit of the third invention is the wave power generation unit of the first or second invention, wherein N wave receiving buckets are provided at regular intervals on a pitch circle centered on the axis of the rotating shaft, and each wave receiving bucket is rotationally symmetric N times with the pitch circle center as the axis of rotational symmetry. In a state where one wave receiving bucket is located at the first position, the other wave receiving buckets are located at the second position.

[0041] According to the wave power generation unit of the third invention, in addition to exhibiting the same actions and effects as the wave power generation unit of the first or second invention, the wave receiving buckets are simultaneously located at the first position and the second position in water. Even when the rotating main body portion and the rotating shaft rotate forward, wave receiving buckets successively come to the first position and the second position simultaneously. Therefore, even if the relative water flow changes moment by moment, its movement can be received by the wave receiving buckets at either the first position or the second position, and can be efficiently converted into the rotational force of the rotating main body portion.

[0042] The wave power generation unit of the fourth invention is the wave power generation unit of any one of the first to third inventions, wherein the wave receiving bucket is formed in a conical shape or a truncated conical shape with an outer diameter gradually increasing from the tip portion toward the wave receiving surface, and the wave receiving surface is a conical or truncated conical concave portion provided on the inner peripheral portion of the wave receiving bucket.

[0043] According to the wave power generation unit of the fourth invention, in addition to having the same actions and effects as any of the wave power generation units of the first to third inventions, since the shape of the wave receiving bucket is formed in a conical shape or a truncated conical shape in which the outer diameter gradually increases from the tip to the wave receiving surface, when the wave receiving rotating body rotates forward, the resistance coefficient when the wave receiving bucket moves relatively in water can be reduced. By having at least a part of the plurality of wave receiving buckets submerged, the rotational resistance received by the wave receiving rotating body can be reduced, and a decrease in the power generation efficiency of the generator operated by the rotation of the wave receiving rotating body can be suppressed.

[0044] The wave power generation unit of the fifth invention is any of the wave power generation units of the first to fourth inventions, wherein the wave receiving bucket includes a bucket body provided at regular intervals on a pitch circle centered on the axis of the rotating shaft on the rotating main body part, a tip part of the bucket body facing the forward rotation direction side of the rotating main body part, a base end part of the bucket body facing the reverse rotation direction side of the rotating main body part opposite to the tip part, a water passage which is a flow path provided to penetrate the inside of the bucket body from the base end part to the tip part of the bucket body, and an on-off valve formed to be reciprocally movable between one of a closed position closing the water passage and an open position opening the water passage and the other, and having a wave receiving surface receiving a relative water flow (hereinafter referred to as "relative forward flow") flowing relatively from the base end part side to the tip part side of the bucket body at the closed position, and a wave receiving member receiving a relative water flow (hereinafter referred to as "relative reverse flow") flowing relatively in a direction opposite to the relative forward flow and moving from the closed position to the open position, wherein the wave receiving member converts the force accompanying the flow of the relative forward flow into a rotational force for rotating the rotating main body part forward when the wave receiving surface receives the relative forward flow at the closed position, and when the wave receiving member receives the relative reverse flow at the closed position, the wave receiving member is moved from the closed position to the open position to open the water passage, and the relative reverse flow is passed through the opened water passage to pass through the inside of the bucket body to reduce the resistance in water received by the bucket body.

[0045] The wave power generation unit of the sixth invention, in the wave power generation unit of the fifth invention, further includes a biasing member that biases the wave receiving member to cause the wave receiving member to return and move from the open position to the closed position. The wave receiving member converts the force associated with the flow of the relative downstream flow into a rotational force for rotating the rotary main body portion by receiving the relative downstream flow at the closed position on the wave receiving surface. On the other hand, when the wave receiving member receives a force exceeding the biasing force of the biasing member from the relative upstream flow at the closed position, the wave receiving member is moved from the closed position to the open position to open the water passage, and the relative upstream flow is allowed to pass through the opened water passage and escape inside the bucket main body to reduce the underwater resistance received by the bucket main body.

[0046] According to the wave power generation unit of the fifth or sixth invention, in addition to having the same operations and effects as the wave power generation unit of any one of the first to fourth inventions, the wave receiving rotating body is rotated forward by receiving the relative downstream flow by a plurality of wave receiving buckets, and at the same time, the underwater resistance exerted by the relative upstream flow opposite to the relative downstream flow on the wave receiving buckets is reduced.

[0047] Specifically, when a relative downstream flow occurs with respect to the bucket main body of the wave receiving bucket, in the case of the fifth invention, due to the force of the relative downstream flow, or in the case of the sixth invention, due to the force of the relative downstream flow and the biasing force of the biasing member, the wave receiving member is moved to the closed position to close the water passage. At the same time, the wave receiving member at the closed position receives the relative downstream flow by its wave receiving surface, so that the wave receiving bucket is pushed in the forward rotation direction of the rotary main body portion, and a rotational force for rotating the rotary main body portion in the forward rotation direction can be obtained. The wave receiving bucket is rotated forward by the rotational force in the forward rotation direction.

[0048] On the one hand, when a relative countercurrent occurs with respect to the bucket body of the wave receiving bucket, in the case of the fifth invention, due to the force of the relative countercurrent, or in the case of the sixth invention, due to the force of the relative countercurrent exceeding the biasing force of the biasing member, the wave receiving member is pushed and moved from the closed position to the open position. By this movement of the wave receiving member, the water passage is opened, and the relative countercurrent is allowed to pass from the tip end side to the base end side of the bucket body through the opened water passage and escape. As a result, the underwater resistance received by the bucket body from this relative countercurrent is reduced. Consequently, it is prevented that the relative countercurrent pushes the wave receiving bucket back in the reverse direction, and it is prevented that the forward rotation of the wave receiving rotating body is inhibited.

[0049] In addition, in the case of the fifth invention, when the force of the relative forward current acts on the wave receiving surface of the wave receiving member, due to the force of the relative forward current, or in the case of the sixth invention, when the strength of the relative countercurrent decreases and becomes weaker than the biasing force of the biasing member, due to the force of the relative forward current, the wave receiving member is returned and moved from the open position to the closed position, and the water passage is closed by the wave receiving member that has returned to the closed position. As a result, the wave receiving surface of the wave receiving member is returned to a state where it is more likely to receive the relative forward current.

[0050] The wave power generation unit of the seventh invention is a wave power generation unit according to any one of the first to sixth inventions, and includes a mooring member that has one end fastened to the floating body and the other end fastened to a weight installed on the seabed itself or on the seabed, and moors the floating body at a fixed location.

[0051] According to the wave power generation unit of the seventh invention, in addition to exhibiting the same actions and effects as the wave power generation unit according to any one of the first to sixth inventions, since the floating body is moored at a fixed location by the mooring member, the floating body can be placed in an offshore location where surface waves that cause fluctuations such as rolling, pitching, and heaving are likely to occur, and power generation can be performed using the surface waves even in a place without incoming waves or outgoing waves such as the shore or its vicinity.

[0052] The wave power generation unit of the eighth invention is a wave power generation unit according to any one of the first to seventh inventions, and has a rotor part which is directly connected to the rotation axis of the wave receiving rotating body or is connected to the rotation axis of the wave receiving rotating body via a connection transmission mechanism and is rotated by the rotational force of its rotation axis. The wave power generation unit is provided with a generator mounted on the floating body, which converts the rotation of the rotor part into electric energy.

[0053] Here, the connection transmission mechanism is a mechanism that is interposed between the rotation axis of the wave receiving rotating body and the rotor part of the generator, connects the rotation axis of the wave receiving rotating body and the rotor part of the generator, and transmits the rotation (force) of the rotation axis of the wave receiving rotating body to the rotor part of the generator.

[0054] The wave power generation unit of the ninth invention is a wave power generation unit according to any one of the first to eighth inventions, in which the wave receiving rotating bodies are respectively provided on both sides in the lateral width direction of the floating body in plan view.

[0055] According to the wave power generation unit of the ninth invention, in addition to having the same actions and effects as the wave power generation unit according to any one of the first to eighth inventions, the wave receiving rotating bodies respectively located on both lateral sides of the floating body (the parts corresponding to the port side and starboard side when the floating body is regarded as a hull) are each rotated by receiving the relative water flow in the water through the wave receiving buckets in the first position and the second position.

[0056] The wave power generation unit of the tenth invention is a wave power generation unit according to any one of the first to ninth inventions, in which the wave receiving rotating bodies are respectively provided on both sides in the longitudinal direction of the floating body in plan view.

[0057] According to the wave power generation unit of the tenth invention, in addition to having the same actions and effects as the wave power generation unit according to any one of the first to ninth inventions, the wave receiving rotating bodies respectively located on both front and rear sides of the floating body (the parts corresponding to the bow side and stern side when the floating body is regarded as a hull) are each rotated by receiving the relative water flow in the water through the wave receiving buckets in the first position and the second position.

[0058] The wave power generation system of the 11th invention includes any one of the wave power generation units of the 1st to 10th inventions, power transmission means for transmitting the power generated by the wave power generation unit, and power facilities for receiving the power transmitted by the power transmission means.

Effect of the Invention

[0059] According to the wave power generation unit and the wave power generation system of the present invention, the wave receiving rotating body provided on the floating body not only converts the movement of the lateral relative water flow into a rotational force through the wave receiving bucket at the second position, but also can convert the movement of the upward relative water flow into a rotational force through the wave receiving bucket at the first position. Therefore, by comprehensively utilizing the rotational forces generated by these relative water flows in different directions, the rotor part of the generator can be rotated to generate electricity. This is completely different from the conventional power generation systems that simply use the flow of push waves and pull waves generated horizontally along the coast to generate electricity, and has the advantageous effect of being able to generate electricity using the surface waves accompanied by the up and down movement occurring on the open sea surface. Thus, it is possible to avoid the influence of the breaking wave impact force caused by the wave breaking phenomenon, and there is also an effect that damage to the wave power generation unit caused by such breaking wave impact force can be reduced.

Brief Description of the Drawings

[0060]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0061] An embodiment of the present invention will be described below with reference to the accompanying drawings. In this embodiment, for the sake of convenience, regarding the wave power generation unit 1 and its floating body 2, the terms of bow, stern, port side, and starboard side are used in the same way as in the case of a ship's hull. Specifically, the left side of FIG. 1(a) and the left side of FIG. 2(a) are defined as the bow part 21, the right side of FIG. 1(a) and the right side of FIG. 2(a) are defined as the stern part 22, the front side of FIG. 1(a) and the lower side of FIG. 2(a) are defined as the port side part 23, and the back side of FIG. 1(a) and the upper side of FIG. 2(a) are defined as the starboard side part 24, and the following description will be made accordingly.

[0062] FIG. 1(a) is a right side view of the wave power generation unit 1 used in a wave power generation system according to an embodiment of the present invention, which is a front projection view from the port side. FIG. 1(b) is a longitudinal sectional view taken along line IB-IB of FIG. 1(a), which is a longitudinal sectional view of the bow portion 21 of the wave power generation unit 1. Note that FIG. 1 shows the state where the floating body 2 is floating on the horizontal water surface 100. The left side view of the wave power generation unit 1, which is a front projection view from the starboard side, appears in a form symmetric to the diagram of FIG. 1(a) with respect to left and right. In FIGS. 1 to 5, each coordinate axis of the space-fixed coordinate system XYZ is shown.

[0063] FIG. 2(a) is a plan view of the wave power generation unit 1, and FIG. 2(b) is a configuration diagram showing the main devices mounted inside the floating body 2. Note that FIG. 2 shows the state where the floating body 2 is floating on the horizontal water surface 100.

[0064] FIG. 3(a) is a side view of the wave receiving rotating body 3 provided on the port side portion 23 of the floating body 2, which is an explanatory diagram of the wave receiving buckets 32 submerged in the water 102 of the wave receiving rotating body 3 from the first position P1 to the fourth position P4. FIG. 3(b) is an enlarged perspective view of the wave receiving bucket 32.

[0065] Here, in FIG. 3(a), the state where the wave receiving rotating body 3 has stopped with the floating body 2 floating on the horizontal water surface 100 is shown. The illustration of the floating body 2 is omitted, all the wave receiving buckets 32 are shown in longitudinal section view, the first position P1 to the fourth position P4 are indicated by a two-dot chain line, and the forward rotation direction of the wave receiving rotating body 3 is indicated by a solid arrow. In FIG. 3(b), only one wave receiving bucket 32 is shown. In FIG. 3, the flow of the relative water flow 103 is shown by a white arrow.

[0066] Here, the relative water flow 103 refers to the relative water flow that occurs in the water 102 based on the rocking motion of the surface wave 101 and the relative motion between the floating body 2 that rocks in response to this surface wave 101. In particular, in FIGS. 3(a) and 5, the sign of the upward relative water flow 103 received by the wave receiving surface 32b of the wave receiving bucket 32P1 is designated as "103a", the sign of the lateral relative water flow 103 received by the wave receiving surface 32b of the wave receiving bucket 32P2 is designated as "103b", the sign of the downward relative water flow 103 received by the wave receiving surface 32b of the wave receiving bucket 32P3 is designated as "103c", and the sign of the lateral relative water flow 103 (the relative water flow in the opposite direction to the relative water flow 103b) received by the wave receiving surface 32b of the wave receiving bucket 32P4 is designated as "103d", respectively.

[0067] FIG. 4 is a longitudinal sectional view of the water 102 in the offshore area, showing the mooring state of the wave power generation unit 1. In FIG. 4, a part of the mooring member 6 and the power transmission line 7 is not shown. FIG. 4 shows a state in which the floating body 2 floats on the horizontal water surface 100.

[0068] FIG. 5 is an explanatory view showing a state in which the wave power generation unit 1 floats on the water surface 100 while receiving the relative water flow 103, as viewed in longitudinal section of the water 102 in the offshore area. FIG. 5(a) is a right side view (projection view from the starboard side) of the wave power generation unit 1, FIG. 5(b) is a left side view (projection view from the port side) of the wave power generation unit 1, and FIG. 5(c) is a front view (projection view from the bow side) of the wave power generation unit 1.

[0069] Here, in FIG. 5, the small white arrows indicate the direction of the relative water flow 103, the large white arrows indicate the movement of the surface wave 101, and the solid arrows indicate the rotation direction of the wave receiving rotating body 3, respectively. Also, in FIG. 5, the sign of the wave receiving bracket 32 at the first position is designated as "32P1", the sign of the wave receiving bracket 32 at the second position is designated as "32P2", the sign of the wave receiving bracket 32 at the third position is designated as "32P3", and the sign of the wave receiving bracket 32 at the fourth position is designated as "32P4", respectively.

[0070] As shown in FIGS. 1 to 5, the wave power generation unit 1 is installed in a floating state on the water surface 100 of the sea, lake, etc. where the surface wave 101 occurs offshore, and generates electricity using the surface wave 101 generated on the water surface 100.

[0071] This wave power generation unit 1 mainly includes a floating body 2, a wave receiving rotating body 3, a connecting and transmitting mechanism 4, a generator 5, and a mooring member 6. The wave power generation system using this wave power generation unit 1 includes, in addition to this wave power generation unit 1, a transmission line 7 and an onshore power facility (not shown).

[0072] As shown in FIG. 1, the floating body 2 is installed on the water surface 100 such as the sea surface or the lake surface, and is formed to be able to float on the water surface 100 through this buoyancy, and sways by receiving the surface wave 101 generated on the water surface 100 (see FIG. 5).

[0073] This floating body 2 receives the swaying motion of the surface wave 101 and moves in the X-axis direction (including both the positive and negative directions of the coordinate axis. The same applies hereinafter), the Y-axis direction, the Z-axis direction, rotates around the X-axis (including both the positive and negative rotations. The same applies hereinafter), rotates around the Y-axis, or rotates in the Z-axis direction, and sways with any one or a combination of two or more of these motions.

[0074] The floating body 2 is formed in a hull shape, and a storage space 25 is provided inside the floating body 2. The storage space 25 is a space for storing the generator 5 and the connecting and transmitting mechanism 4 inside, and the floating body 2 itself serves as a storage housing 26 that covers the entire storage space 25. This storage housing 26 is a housing that covers the storage space 25 in a sealed state, prevents water such as seawater or lake water from entering the storage space 25 from the outside, and prevents the generator 5 and the connecting and transmitting mechanism 4 from being submerged.

[0075] As shown in Fig. 2(a), this floating body 2 includes a bow portion 21 which is the front portion thereof, a stern portion 22 which is the rear portion thereof, a starboard portion 24 which is the right side portion thereof, and a port portion 23 which is the left side portion thereof. On this floating body 2, wave receiving rotators 3 are respectively provided on the port portion 23 (lower left side in Fig. 2(a)) and starboard portion 24 (upper left side in Fig. 2(a)) on the bow portion 21 side, and on the port portion 23 (lower right side in Fig. 2(a)) and starboard portion 24 (upper right side in Fig. 2(a)) on the stern portion 22 side. In total, four wave receiving rotators 3 are provided on the floating body 2 in the front, rear, left, and right directions.

[0076] These four wave receiving rotators 3 in total in the front, rear, left, and right directions are rotationally driven by receiving the relative water flow 103 (see Fig. 5) in the water 102. Each wave receiving rotator 3 has a water wheel shape, is formed in the same form, and is configured to rotate in the same direction as the normal rotation direction. All the wave receiving rotators 3 are rotationally driven by receiving the relative water flow 103 generated in the water 102, and each includes a rotation main body portion 31, a plurality of wave receiving buckets 32, and a rotation shaft 33.

[0077] As shown in Fig. 1, the rotation main body portion 31 of the wave receiving rotator 3 is an annular body which is the main body portion of the wave receiving rotator 3, and is formed in a substantially circular shape in side view. A boss portion 31a is provided at the center of this rotation main body portion 31, and the rotation shaft 33 is fixed to this boss portion 31a. This rotation shaft 33 is the rotation shaft 33 of the wave receiving rotator 3 and its rotation main body portion 31, and is integrally formed with the rotation main body portion 31. Further, the rotation shaft 33 is rotatably supported by the floating body 2 via a bearing 26 (see Fig. 2(b)) provided on the floating body 2 (see Fig. 1(b)).

[0078] As shown in Fig. 2(b), the rotation shaft 33 of the wave receiving rotator 3 is a shaft body whose axis coincides with the rotation center of the rotation main body portion 31. While the rotation main body portion 31 is connected to the base end portion thereof, a connection transmission mechanism 4 is connected to the tip end portion thereof.

[0079] The connection transmission mechanism 4 is interposed between the rotation axis 33 of the wave receiving rotating body 3 and the rotor part 51 of the generator 5, connects the rotation axis 33 of the wave receiving rotating body 3 and the rotor part 51 of the generator 5, and transmits the rotation (force) of the rotation axis 33 of the wave receiving rotating body 3 to the rotor part 51 of the generator 5. It mainly includes a speed increaser 41 and a flywheel 42.

[0080] The speed increaser 41 includes a low-speed input shaft 41a that is rotated by receiving a rotational force from the outside, a plurality of gears (not shown) that increase the speed of the rotation input from the low-speed input shaft 41a and output it, and a high-speed output shaft 41b that rotates at the increased rotational speed output from the plurality of gears. According to this speed increaser 41, the rotation axis 33 of the wave receiving rotating body 3 is coaxially connected to the low-speed input shaft 41a, and the rotor part 51 of the generator 5 is coaxially connected to the high-speed output shaft 41b via the flywheel 42. Therefore, the rotor part 51 of the generator 5 and the flywheel 42 rotate at a higher speed than the wave receiving rotating body 3 and its rotation axis 33.

[0081] The flywheel 42 is what is called a so-called resilient wheel. When the rotational force obtained by the rotation of the wave receiving rotating body 3 is transmitted to the flywheel 42 via the speed increaser 41, the flywheel 42 rotates and accumulates as rotational inertia energy. This flywheel 42 is housed in a casing 42a and is pivotally supported by a low-friction bearing 42b, so that the rotational inertia energy obtained by the rotation of the wave receiving rotating body 3 can be accumulated in a low-loss state.

[0082] Since the flywheel 42 can accumulate the rotational inertia energy obtained by the rotation of the wave receiving rotating body 3 in this way, for example, even in a situation where the surface wave 101 temporarily weakens and the rotation of the wave receiving rotating body 3 stops or decreases, the rotational inertia energy accumulated in the flywheel 42 can be used to rotate the rotor part 51 of the generator 5 and continue power generation.

[0083] The generator 5 includes a stator part (not shown) that is fixed to the casing 52 and generates a magnetic field, and a rotor part 51 that is rotatably provided within the stator part and rotates within the magnetic field of the stator part. This generator 5 is a device that converts the rotation of the rotor part 51 into electrical energy. The rotor part 51 rotates within the magnetic field generated by the stator part, and an electromotive force is generated by electromagnetic induction to perform power generation.

[0084] Also, in this generator 5, one end (the left side in FIG. 3(b)) of the main shaft 51a of the rotor part 51 and the central axis 42a of the flywheel 42 are connected and fixed coaxially, and the other end (the right side in FIG. 3(b)) of the central axis 42a of this flywheel 42 and the high-speed output shaft 41b of the speed increaser 41 are connected and fixed coaxially. Therefore, the rotation of the wave receiving rotating body 3 rotates the flywheel 42 and the rotor part 51 of the generator 5 via the speed increaser 41.

[0085] Each generator 5 of the wave power generation unit 1 converts the kinetic energy generated by the rotation of the plurality of wave receiving rotating bodies 3 into electric power, and this generated electric power is sent to a power facility (not shown) on land via the power transmission line 7 connected to each generator 5.

[0086] As shown in FIG. 3(a), the wave receiving rotating body 3 includes a rotating main body part 31, a rotating shaft 33, a plurality of wave receiving buckets 32, and a wave receiving surface 32b formed on each wave receiving bucket 32. Note that each of the plurality of wave receiving rotating bodies 3 provided on the floating body 2 has the same form, and all of them are formed in the shape of a water wheel as a whole. Therefore, in FIG. 3, only one wave receiving rotating body 3 will be described.

[0087] According to this wave receiving rotating body 3, its rotating main body 31 is a member that supports a plurality of wave receiving buckets 32 at predetermined positions, and the plurality of wave receiving buckets 32 are all formed in the same form. In a state where the floating body 2 floats on the horizontal water surface 100, all of the plurality of wave receiving buckets 32 of this wave receiving rotating body 3 are in a state of being submerged in the water 102, and by directly receiving the relative water flow 103 with these wave receiving buckets 32, it is a member that generates the rotational force required to rotate the rotor portion 51 of the generator 5.

[0088] A plurality of wave receiving buckets 32 are provided at predetermined intervals on the entire outer circumference of the rotating main body 31 of the wave receiving rotating body 3. A plurality of wave receiving buckets 32 are provided at regular intervals of eight on a pitch circle P centered on the axis of the rotating shaft 33 of the rotating main body 31, and each wave receiving bucket 32 is eight-fold symmetric with the center of the pitch circle P as the axis of rotational symmetry, and is provided at equal intervals on the entire outer circumference of the rotating main body 31.

[0089] Each wave receiving bucket 32 has a pointed end portion 32a with a pointed shape facing the forward rotation direction side (the direction of the arrow in FIG. 3(a)) of the rotating main body 31. Further, each wave receiving bucket 32 has a wave receiving surface 32b formed on the end surface facing the reverse direction side (the opposite arrow direction in FIG. 3(a)) from the pointed end portion 32a, and this wave receiving surface 32b has a shape that is recessed toward the pointed end portion 32a side. Further, each wave receiving bucket 32 has a pointed outer peripheral surface 32c formed in a shape where the outer diameter gradually decreases from the wave receiving surface 32b toward the pointed end portion 32a.

[0090] As shown in FIG. 3(b), the wave receiving bucket 32 is formed in a conical outer shape whose outer diameter gradually increases from the pointed end portion 32a toward the wave receiving surface 32b, and its pointed outer peripheral surface 32c is formed in a tapered shape. Further, the wave receiving surface 32b of the wave receiving bucket 32 is a conical concave portion provided in the inner peripheral portion of the wave receiving bucket 32 having the conical shape.

[0091] Here, since the tip 32a and the tapered outer peripheral surface 32c of the wave receiving bucket 32 are generally conical in shape, when the wave receiving bucket 32 rotates in the forward rotation direction (the direction of the solid arrow in FIG. 5), the resistance received from the water in the water 102 can be reduced.

[0092] As shown in FIG. 3(a), in the wave receiving rotating body 3, with the floating body 2 floating on the water surface 100, all of the plurality of wave receiving buckets 32 are in a state of being submerged in the water 102. Among the submerged wave receiving buckets 32, four wave receiving buckets 32 are respectively located at a first position P1 where the wave receiving surface 32b faces downward, a second position P2 where the wave receiving surface 32b faces sideways (toward the rear of the floating body 2), a third position P3 where the wave receiving surface 32b faces upward, and a fourth position P4 where the wave receiving surface 32b faces sideways (toward the front of the floating body 2).

[0093] Here, according to this wave power generation unit 1, even when receiving the rocking motion of the surface wave 101 and the rocking of the floating body 2, all or almost all of the plurality of wave receiving rotating bodies 3 are in a state of being submerged in the water 102. In particular, for the wave receiving buckets 32P1, 32P2, 32P3 located at the first position P1, the third position P3, and the second position P2, regardless of the rocking motion of the surface wave 101 and the floating body 2, they are always maintained in a state of being submerged in the water 102.

[0094] Among the wave receiving buckets 32 submerged in the water 102, at least the wave receiving bucket 32 at the first position P1 receives the relative water flow 103 generated in the water 102 with its downward wave receiving surface 32b, the wave receiving bucket 32 at the second position P2 which has rotated approximately 90° in the reverse rotation direction around the axis of the rotation shaft 33 from the first position P1 receives the relative water flow 103 with its sideways (toward the rear of the floating body 2) wave receiving surface 32b, the wave receiving bucket 32 at the third position P3 which has rotated approximately 90° in the reverse rotation direction around the axis of the rotation shaft 33 from the second position P2 receives the relative water flow 103 with its downward wave receiving surface 32b, and the wave receiving bucket 32 at the fourth position P4 which has rotated approximately 90° in the reverse rotation direction around the axis of the rotation shaft 33 from the third position P3 receives the relative water flow 103 with its sideways (toward the front of the floating body 2) wave receiving surface 32b, and thereby applies a rotational force to the rotation main body 31.

[0095] That is, the wave receiving rotating body 3 is associated such that the wave receiving surface 32b of the wave receiving bucket 32P1 at the first position P1 receives the relative water flow 103a, the wave receiving surface 32b of the wave receiving bucket 32P2 at the second position P2 receives the relative water flow 103b, the wave receiving surface 32b of the wave receiving bucket 32P3 at the third position P3 receives the relative water flow 103c, and the wave receiving surface 32b of the wave receiving bucket 32P4 at the fourth position P4 receives the relative water flow 103d.

[0096] Therefore, according to the plurality of wave receiving buckets 32, the wave receiving surface 32b of the wave receiving bucket 32P1 at the first position P1 faces downward and receives and is pushed by the upward relative water flow 103a, the wave receiving surface 32b of the wave receiving bucket 32P2 at the second position P2 faces sideways (a posture facing the rear of the floating body 2 (the right side in Fig. 3(a))) and receives and is pushed by the sideways relative water flow 103b (a water flow coming from the rear of the floating body 2 relatively), the wave receiving surface 32b of the wave receiving bucket 32P3 at the third position P3 faces upward and receives and is pushed by the downward relative water flow 103c, and the wave receiving surface 32b of the wave receiving bucket 32P4 at the fourth position P4 faces sideways (a posture facing the front of the floating body 2 (the left side in Fig. 3(a)), that is, the opposite direction to the wave receiving surface 32b of the wave receiving bucket 32P2 at the second position P2) and receives and is pushed by the sideways relative water flow 103d (a water flow coming from the front of the floating body 2 relatively, that is, the opposite direction to the sideways relative water flow 103b received by the wave receiving surface 32b of the wave receiving bucket 32P2 at the second position P2). As a result, the wave receiving rotating body 3 is rotated in the forward rotation direction.

[0097] However, the relative water flow 103 inside the water 102 is not necessarily limited to the vertical and horizontal water flows like the relative water flows 103a to 103d. Depending on the situation at that time, the movement of the relative water flow 103 may occur in a direction different from these directions. As a result, among the plurality of wave receiving buckets 32 in the submerged state, it is not only the wave receiving buckets 32 at the first position P1 to the fourth position P4 that receive the movement of the relative water flow 103 on the wave receiving surface 32b and apply a rotational force to the wave receiving rotator 3. Even at a position different from the first position P1 to the fourth position P4, the wave receiving bucket 32 receives the relative water flow 103 on its wave receiving surface 32b and applies a rotational force to the wave receiving rotator 3.

[0098] That is, it is naturally possible that a wave receiving bucket 32 submerged at a position different from the first position P1 to the fourth position P4 receives the relative water flow 103 coming toward its wave receiving surface 32b and generates a rotational force that rotates the wave receiving rotator 3 in the forward rotation direction. It is obvious that the same applies to the second embodiment described later.

[0099] As shown in FIG. 4, the mooring member 6 is a string-like or wire-like member such as a wire or a chain for mooring the floating body 2 at a fixed location. One end of this mooring member 6 is attached to the floating body 2, and the other end is attached to a weight 8 installed on the bottom 104 of the water. Further, this weight 8 is, for example, a weight such as a weight or an anchor. Note that the other end (lower end) of the mooring member 6 may be fixed by driving it into the bottom 104 itself.

[0100] As shown in FIG. 5, according to the wave power generation unit 1, the floating body 2 floats in the off-shore water area via buoyancy. In the off-shore water area, in the water 102 when viewed in a longitudinal cross-section of the water area, the fluid particles move in a circular motion or an elliptical motion close to this (an elliptical motion having a minor axis in the vertical direction and a major axis in the horizontal direction) when viewed from the side. The movement of the surface wave 101 is such that the water surface 100 where the floating body 2 exists and the water 102 near the water surface 100 reciprocate in the horizontal direction and also reciprocate in the vertical direction (vertical direction).

[0101] As the surface wave 101 sways horizontally and vertically in this way, the floating body 2 of the wave power generation unit 1 also sways on the water surface 100, and a relative water flow 103 is generated with respect to the floating body 2 and each wave receiving rotating body 3 based on the sway of the floating body 2 and the movement of the surface wave 101.

[0102] All the wave receiving rotating bodies 3 are in a state where all their wave receiving buckets 32 are submerged in the water 102, and each wave receiving surface 32b of the wave receiving buckets 32P1, 32P2, 32P3, 32P4 at the first position P1 to the fourth position P4 rotates in the forward rotation direction by receiving the corresponding relative water flows 103a, 103b, 103c, 103d.

[0103] Specifically, the wave receiving bucket 32P1 at the first position P1 has its wave receiving surface 32b facing downward when the floating body 2 floats on the water surface 100, and when an upward relative water flow 103a acts toward this wave receiving surface 32b, the wave receiving bucket 32P1 at the first position P1 is relatively pushed upward and the rotation main body 31 and the rotating shaft 33 are rotated in the forward rotation direction (the direction of the solid arrow in FIG. 5).

[0104] Therefore, the wave receiving bucket 32P1 at the submerged first position P1 converts not the relative water flows 103b, 103d that act as external forces in the lateral directions such as front, rear, left, and right, but rather the relative water flow 103a that acts as an external force upward, into the rotational motion of the rotating shaft 33 of the wave receiving rotating body 3.

[0105] Also, the wave receiving bucket 32P3 at the submerged third position P3 has its wave receiving surface 32b facing upward when the floating body 2 floats on the water surface 100, and when a downward relative water flow 103c acts toward this wave receiving surface 32b, the wave receiving bucket 32P3 at the third position P3 is relatively pushed downward and the rotation main body 31 and the rotating shaft 33 are rotated in the forward rotation direction (the direction of the solid arrow in FIG. 5).

[0106] Therefore, the receiving bucket 32P3 at the submerged third position P3 converts the relative water flow 103c that applies an external force downward, rather than the relative water flows 103b and 103d that apply external forces in lateral directions such as front, rear, left, and right, into the rotational movement of the rotation axis 33 of the wave receiving rotating body 3.

[0107] For example, when the floating body 2 sways due to the surface wave 101, such as rolling (see Fig. 5(c)), pitching (see Figs. 5(a) and 5(b)), or heaving (see Figs. 5(a) and 5(b)), the relative water flow 103 generated in the water 102 acts as an upward relative water flow 103a on the wave receiving surface 32b of the receiving bucket 32P1 at the first position P1, and acts as a downward relative water flow 103c on the wave receiving surface 32b of the receiving bucket 32P3 at the third position P3. The rotation main body 31 and the rotation axis 33 are rotated forward through the external forces received by the receiving buckets 32P1 and 32P3 at the first position P1 and the third position P3.

[0108] On the other hand, the receiving bucket 32P2 at the submerged second position P2 has its wave receiving surface 32b facing laterally when the floating body 2 is floating on the water surface 100. When the lateral relative water flow 103b acts toward this wave receiving surface 32b, the receiving bucket 32P2 at the second position P2 is relatively pushed and moved laterally, and the rotation main body 31 and the rotation axis 33 are rotated in the forward rotation direction.

[0109] Therefore, the receiving bucket 32P2 at the submerged second position P2 converts the relative water flows 103b and 103d that apply external forces in lateral directions such as front, rear, left, and right, rather than the relative water flows 103a and 103c that move upward and apply external forces, into the rotational movement of the rotation axis 33 of the wave receiving rotating body 3.

[0110] In addition, the receiving bucket 32P4 at the submerged fourth position P4 has its receiving surface 32b oriented horizontally when the floating body 2 is floating on the water surface 100, and a relatively horizontal water flow 103d acts on this receiving surface 32b in the horizontal direction. As a result, the receiving bucket 32P4 at the fourth position P4 is relatively pushed and moved horizontally, and the rotating body portion 31 and the rotating shaft 33 are rotated in the forward rotation direction.

[0111] Therefore, the receiving bucket 32P4 at the submerged fourth position P4 converts not the relatively upward and downward water flows 103a and 103c that move upward and act with an external force, but rather the relatively horizontal water flows 103b and 103d that act with an external force in the horizontal direction such as front, rear, left, and right, into the rotational movement of the rotating shaft 33 of the wave receiving rotating body 3.

[0112] For example, when assuming that the direction parallel to and perpendicular to the rotating shaft 33 of the wave receiving rotating body 3 is the front-rear direction of the floating body 2, when the floating body 2 receiving the surface wave 101 sways such as pitching (surging) and yawing (yawing), the relatively horizontal water flow 103b acts on the receiving surface 32b of the receiving bucket 32P2 at the second position P2 as a relatively horizontal water flow in the horizontal direction, and the relatively horizontal water flow 103d acts on the receiving surface 32b of the receiving bucket 32P4 at the fourth position P4 as a relatively horizontal water flow in the horizontal direction. The rotating body portion 31 and the rotating shaft 33 are rotated forward through the external forces received by the receiving buckets 32P2 and 32P4 at the second position P2 and the fourth position P4.

[0113] That is, according to this wave receiving rotating body 3, not only the movement of the relatively horizontal water flows 103b and 103d but also the movement of the relatively upward and downward water flows 103a and 103c can be converted into a driving force for rotating the wave receiving rotating body 3.

[0114] According to the wave power generation unit 1 in this way, each wave receiving rotating body 3 thereof receives an external force from the corresponding relative water flows 103a to 103d and other relative water flows 103 with respect to the wave receiving surfaces 32b of the wave receiving buckets 32P1 to 32P4 and other wave receiving buckets 32, and is rotated in its forward rotation direction. Due to this rotation, the rotor part 51 of the generator 5 is rotated via the connection transmission mechanism 4 to generate electricity, and the generated electric power is transmitted to the power facility via the transmission line 7.

[0115] FIG. 6 is a side view of the wave receiving rotating body 130 related to the wave power generation unit of the second embodiment, and is an explanatory diagram of the first position P1 to the fourth position P4 of the wave receiving bucket 131 submerged in the water 102 in the wave receiving rotating body 130. In FIG. 6, for the sake of convenience, the state where the wave receiving members 133 of all the wave receiving buckets 131 are in the closed position is illustrated.

[0116] FIG. 7 is an explanatory diagram for explaining the operation of the wave receiving bucket 131 used in the wave receiving rotating body 130 of the wave power generation unit of the second embodiment. FIG. 7(a) is a perspective view showing the state where the wave receiving member 133 closes the tip opening 132c1 in the wave receiving bucket 131. FIG. 7(b) is a longitudinal sectional view showing the internal structure of the wave receiving bucket 131 in FIG. 7(a). FIG. 7(c) is a perspective view showing the state where the wave receiving member 133 of the wave receiving bucket 131 opens the tip opening 132c1. FIG. 7(d) is a longitudinal sectional view showing the internal structure of the wave receiving bucket 131 in FIG. 7(c).

[0117] Here, in FIG. 6, the state where the wave receiving rotating body 130 stops with the floating body floating on the horizontal water surface is illustrated. The illustration of the floating body is omitted, all the wave receiving buckets 131 are viewed in longitudinal section, the first position P1 to the fourth position P4 are indicated by a two-dot chain line, and the forward rotation direction of the wave receiving rotating body 130 is indicated by a solid line arrow. In FIG. 7, only one wave receiving bucket 131 is illustrated.

[0118] In FIGS. 6 and 7, the flow of the relative water flow 103 is illustrated by white arrows. The relative water flow 103 indicated by the white arrows in FIGS. 6, 7(a), and 7(b) represents the "relative forward flow 103A" which is the relative water flow 103 flowing from the base end portion side to the tip end portion side of the bucket body 132. The relative water flow 103 indicated by the white arrows in FIGS. 7(c) and 7(d) represents the "relative reverse flow 103B" which is the relative water flow 103 flowing in the direction opposite to the relative forward flow 103A, that is, from the base end portion side to the tip end portion side of the bucket body 132.

[0119] Also, the base end portion of the bucket body 132 refers to the portion having the base end face 132a and the base end opening 132a1, and the tip end portion of the bucket body 132 refers to the portion of the bucket body 132 having the tip end face 132c, the tip end opening 132c1, and the tip end partition 132d, which will be described later. Note that the "base end" of the bucket body 132 is also the "base end" of the wave receiving bucket 131, and the "tip end" of the bucket body 132 is also the "tip end" of the wave receiving bucket 131.

[0120] Also, the state (form) of the wave receiving member 133 illustrated in FIG. 6 indicates the state in which this wave receiving member 133 exists (is located) at the closed position, and the state (form) of the wave receiving member 133 shown in FIGS. 7(a) and 7(b) indicates the state in which this wave receiving member 133 exists (is located) at the open position.

[0121] The wave power generation unit of the second embodiment is obtained by changing the form of the wave receiving bucket 131 of the wave receiving rotating body 130 with respect to the wave power generation unit 1 of the first embodiment. In this second embodiment, the wave receiving rotating body 130 and its wave receiving bucket 131 will be described. The same parts as those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted, and different parts are denoted by different reference numerals and their descriptions are given. Note that in the second embodiment, for the parts denoted by different reference numerals from those in the first embodiment, the descriptions of the contents identical to those in the first embodiment are also omitted.

[0122] As shown in Fig. 6, the wave-receiving rotating body 130 used in the wave power generation unit of the second embodiment is provided with a plurality of wave-receiving buckets 131 having a different form from the wave-receiving bucket 131 of the first embodiment on the rotating main body 31. In Fig. 6, only one wave-receiving rotating body 130 is illustrated, but two or more such wave-receiving rotating bodies 130 may be provided on the floating body (not shown) of this wave power generation unit.

[0123] The wave-receiving rotating body 130 of the second embodiment is provided with a plurality of wave-receiving buckets 131 and has a water wheel-like form as a whole. Each of the wave-receiving buckets 131 of this wave-receiving rotating body 130 is formed in the same form. Here, eight wave-receiving buckets 131 are provided at regular intervals on the pitch circle P on the entire outer circumference of the rotating main body 31 of the wave-receiving rotating body 130, and are symmetric eight times with the center of the pitch circle P as the rotation symmetry axis, and are provided at equal intervals on the entire outer circumference of the rotating main body 31.

[0124] The wave-receiving bucket 131 includes a bucket main body 132 formed in a hollow cylindrical rectangular parallelepiped with a space provided in its inner peripheral portion. This bucket main body 132 includes a wave-receiving member 133 having a wave-receiving surface 133a for receiving the relative water flow 103 (assumed forward flow 103A). Further, the bucket main body 132 is fixed to the rotating main body 31 such that its tip portion faces the forward rotation direction (the direction of the solid arrow in Fig. 6) side of the rotating main body 31 and its base end portion faces the reverse rotation direction (the opposite direction of the solid arrow in Fig. 6) side of the rotating main body 31.

[0125] Note that the outer shape of the bucket main body 132 is not limited to a hollow cylindrical rectangular parallelepiped, and may be, for example, a polygonal prism, a cylinder, or other outer shapes as long as it is hollow cylindrical.

[0126] As shown in FIGS. 7(a) and 7(b), the bucket body 132 has a base end opening 132a1 which is an opening with a rectangular shape in a front view on its base end face 132a. On the back side of this base end opening 132a1, a water receiving space 132b is formed which is a space provided in the inner peripheral part of the bucket body 132 and receives the relative water flow 103 (relative forward flow 103A). This water receiving space 132b is communicated with the base end opening 132a1, and the relative water flow 103 (relative forward flow 103A) can flow into the water receiving space 132b from this base end opening 132a1.

[0127] A wave receiving member 133 is provided at the innermost part of the water receiving space 132b. This wave receiving member 133 is a plate-shaped on-off valve for receiving the relative water flow 103 (relative forward flow 103A) flowing into the water receiving space 132b from the base end opening 132a1. The surface of this wave receiving member 133 facing the base end opening 132a1 side (the reverse direction of the rotating main body part 31 (the opposite direction of the solid line arrow in FIG. 6)) is the wave receiving surface 133a. By blocking the relative water flow 103 (relative forward flow 103A) in the water receiving space 132b by this wave receiving surface 133a, the force of the relative water flow 103 (relative forward flow 103A) flowing into the water receiving space 132b acts on the wave receiving bucket 131 as an external force, and the wave receiving rotating body 130 rotates forward.

[0128] As shown in FIGS. 7(b) and 7(c), the bucket body 132 has a tip opening 132c1 which is an opening with a rectangular shape in a front view on its tip face 132c. This tip opening 132c1 is formed in the central part of a tip partition wall 132d which is a partition wall at the tip part of the bucket body 132, and is communicated with the innermost part of the water receiving space 132b of the bucket body 132 (see FIGS. 7(c) and 7(d)). Further, the tip opening 132c1 is blocked by the wave receiving member 133 (see FIG. 7(b)).

[0129] As described above, the wave receiving member 133 has the wave receiving surface 133a and functions to receive the relative water flow 103 (relative forward flow 103A). On the other hand, it also functions as an on-off valve for opening and closing the tip opening 132c1.

[0130] As shown in Fig. 7(b), the wave receiving member 133 is formed such that the back surface (hereinafter referred to as the "opening operation surface") 133b of its wave receiving surface 133a is in contact with the inner surface of the tip partition wall 132d of the bucket body 132, and in this contact state (closed position), the tip opening 132c1 is closed. At the same time, due to the contact between the opening operation surface 133b and the tip partition wall 132d, the wave receiving member 133 is stopped at the closed position and is prohibited from rotating further in the closing direction.

[0131] In addition, the wave receiving member 133 is pivotally supported by the bucket body 132 in a state where it can swing freely within the water receiving space 132b via a swing shaft 133c. Further, the wave receiving member 133 is elastically biased toward the tip partition wall 132d about its swing shaft 133c by a biasing member (not shown) such as an elastic spring. The solid arrows in Fig. 7 indicate the biasing direction by the biasing member.

[0132] The back surface of the wave receiving surface 133a of the wave receiving member 133 is the opening operation surface 133b. When an external force exceeding the biasing force of the biasing member acts on the opening operation surface 133b, the wave receiving member 133 swings about the swing shaft 133c in the direction opposite to the biasing direction (the direction opposite to the solid arrow in Fig. 7), and as shown in Figs. 7(a) and 7(b), it moves from the state of closing the tip opening 132c1 at the closed position to the open position as shown in Figs. 7(c) and 7(d), opening the tip opening 132c1 of the bucket body 132 and shifting to a state where the tip opening 132c1 communicates with the innermost part of the water receiving space 132b.

[0133] Here, the elastic biasing force of the biasing member biasing the wave receiving member 133 is a relatively weak force sufficient to lightly contact the wave receiving member 133 with the tip partition wall 132d. Due to such a weak biasing force, even if the relative water flow 103 (relative countercurrent 103B) pushing the opening operation surface 133b of the wave receiving member 133 from the tip opening 132c1 is a relatively weak flow, the wave receiving member 133 can be easily tilted about the swing shaft 133c to open the tip opening 132c1.

[0134] Therefore, according to the receiving bucket 131, when the relative water flow 103 (relative reverse flow 103B) flowing toward the front end surface 132c of the bucket main body 132 collides with the opening operation surface 133b of the receiving member 133 through the front end opening 132c1, the opening operation surface 133b of the receiving member 133 is pushed inward of the bucket main body 132 so that the relative water flow 103 (relative reverse flow 103B) resists the biasing force of the biasing member, and the receiving member 133 is rotated about the swing shaft 133c and tilted (moved) in the direction opposite to the counter-biasing direction of the biasing member (the direction opposite to the solid arrows in FIGS. 7(a) and 7(b)).

[0135] As a result, with respect to the relative water flow 103 that inhibits the forward rotation of the receiving rotating body 130 (the relative water flow 103 (relative reverse flow 103B) in the direction indicated by the white arrows in FIGS. 7(c) and 7(d)), that is, the relative water flow 103 (relative reverse flow 103B) that attempts to collide with the front end surface 132c of the bucket main body 132, by pushing down the receiving member 133 to the tilted posture (the posture at the open position), it is possible to allow the water to pass through the inside of the receiving bucket 131 from the front end opening 132c1 through the water receiving space 132b to the base end opening 132a1. Therefore, it is possible to prevent the relative water flow 103 (relative reverse flow 103B) from colliding properly with the front end portion of the receiving bucket 131 and becoming a resistance that inhibits the forward rotation of the receiving rotating body 130.

[0136] Thus, according to the receiving rotating body 130 of the second embodiment, as shown in FIGS. 7(a) and 7(b), with respect to the relative water flow 103 (relative forward flow 103A (the white arrows in FIGS. 7(a) and 7(b))) flowing toward the base end opening 132a1 of the receiving bucket 131, that is, the relative water flow 103 (relative forward flow 103A) that attempts to rotate the receiving rotating body 130 forward, the receiving surface 133a of the receiving member 133 receives the relative water flow 103 (relative forward flow 103A) within the water receiving space 132b of the bucket main body 132, and it is possible to convert it into a rotational force that rotates the receiving rotating body 130 in the forward rotation direction.

[0137] On the other hand, according to the receiving wave rotating body 130 of the second embodiment, as shown in FIGS. 7(c) and 7(d), for the relative water flow 103 (relative countercurrent 103B (the white arrows in FIGS. 7(c) and 7(d))) flowing toward the tip of the receiving wave bucket 131, that is, the relative water flow 103 (relative countercurrent 103B) that attempts to reverse the receiving wave rotating body 130, since it originally inhibits the forward rotation of the receiving wave rotating body 130, in order to reduce the resistance of such relative water flow 103 (relative countercurrent 103B), the force of such relative water flow 103 (relative countercurrent 103B) is used to tilt the receiving wave member 133 about the swing axis 133c to open the tip opening 132c1, and the relative water flow 103 (relative countercurrent 103B) is allowed to pass through the receiving water space 132b from such tip opening 132c1 and pass through the base end opening 132a1 and escape, thereby reducing the resistance that the receiving wave bucket 131 receives from water in the water 102, reducing the resistance to receiving water from water in the water 102 that inhibits the forward rotation of the receiving wave rotating body 130, and promoting the forward rotation of the receiving wave rotating body 130.

[0138] Here, the water passage 132e, which is a flow path formed by connecting the tip opening 132c1, the water receiving space 132b, and the base end opening 132a1 and penetrating from the base end surface 132a to the tip end surface 132c of the bucket body 132, is a flow path that is opened and closed with the receiving wave member 133 serving as an on-off valve.

[0139] When the strength of the relative countercurrent 103A decreases and becomes weaker than the biasing force of the biasing member, the receiving wave member 133 is returned from the open position (the position of the receiving wave member 133 shown in FIGS. 7(c) and 7(d)) where it is tilted by the biasing force of this biasing member to the closed position (the position of the receiving wave member 133 shown in FIGS. 7(a) and 7(b)) where it is inverted, and the water passage 132e is blocked by the receiving wave member 133 that has returned to this closed position. As a result, the receiving wave surface 133a of the receiving wave member 133 is returned to a state where it can receive the relative forward flow 103B.

[0140] Incidentally, as shown in FIG. 6, in a state where a floating body (not shown) is floating on the water surface, all of the plurality of wave receiving buckets 131 are submerged in the water 102. Among the submerged wave receiving buckets 131, four wave receiving buckets 131 are respectively positioned at a first position P1 where the wave receiving surface 133a faces downward, a second position P2 where the wave receiving surface 133a faces sideways (toward the rear side (right side in FIG. 6) of the floating body), a third position P3 where the wave receiving surface 133a faces upward, and a fourth position P4 where the wave receiving surface 133a faces sideways (toward the front side (left side in FIG. 6) of the floating body).

[0141] Here, according to the wave power generation unit of this second embodiment, similar to the wave power generation unit 1 of the first embodiment, even when receiving the rocking motion of the surface wave and the rocking of the floating body, all or almost all of the plurality of wave receiving rotators 130 are in a state of being submerged in the water 102. In particular, for the wave receiving buckets 131 positioned at the first position P1, the third position P3, and the second position P2, regardless of the surface wave and the rocking motion of the floating body, a state of always being submerged in the water 102 is maintained.

[0142] As shown in FIG. 6, among the wave receiving buckets 131 submerged in the water 102, at least the wave receiving bucket 131P1 at the first position P1 has its downward wave receiving surface 133a, the wave receiving bucket 131P2 at the second position P2 which has rotated approximately 90° in the reverse direction around the axis of the rotation axis 33 from the first position P1 has its sideways (toward the rear side (right side in FIG. 6) of the floating body) wave receiving surface 133a, the wave receiving bucket 131P3 at the third position P3 which has rotated approximately 90° in the reverse direction around the axis of the rotation axis 33 from the second position P2 has its downward wave receiving surface 133a, and the wave receiving bucket 131P4 at the fourth position P4 which has rotated approximately 90° in the reverse direction around the axis of the rotation axis 33 from the third position P3 has its sideways (toward the front side (left side in FIG. 6) of the floating body) wave receiving surface 133a. They respectively receive the relative water flows 103a to 103d generated in the water 102 and apply a rotational force to the rotation main body 31.

[0143] That is, the wave receiving rotating body 130 is associated such that the wave receiving surface 133a of the wave receiving bucket 131P1 at the first position P1 receives the relative water flow 103a, the wave receiving surface 133a of the wave receiving bucket 131P2 at the second position P2 receives the relative water flow 103b, the wave receiving surface 133a of the wave receiving bucket 131P3 at the third position P3 receives the relative water flow 103c, and the wave receiving surface 133a of the wave receiving bucket 131P4 at the fourth position P4 receives the relative water flow 103d, respectively.

[0144] Therefore, according to the plurality of wave receiving buckets 131, the wave receiving surface 133a of the wave receiving bucket 131P1 at the first position P1 faces downward and is pushed by receiving the upward relative water flow 103a, the wave receiving surface 133a of the wave receiving bucket 131P2 at the second position P2 faces sideways (the posture facing the rear of the floating body (right side in FIG. 6)) and is pushed by receiving the sideways relative water flow 103b (the water flow coming from the rear of the floating body (right side in FIG. 6) relatively), the wave receiving surface 133a of the wave receiving bucket 131P3 at the third position P3 faces upward and is pushed by receiving the downward relative water flow 103c, and the wave receiving surface 133a of the wave receiving bucket 131P4 at the fourth position P4 faces sideways (the posture facing the front of the floating body 2 (left side in FIG. 6), that is, the opposite direction to the wave receiving surface 133a of the wave receiving bucket 131P2 at the second position P2) and is pushed by receiving the sideways relative water flow 103d (the water flow coming from the front of the floating body 2 relatively, that is, the opposite direction to the sideways relative water flow 103b received by the wave receiving surface 133a of the wave receiving bucket 131P2 at the second position P2). As a result, the wave receiving rotating body 130 is rotated in the forward rotation direction.

[0145] The present invention has been described based on the embodiments. However, it can be easily inferred that the present invention is not limited to the above embodiments at all, and various improvements and modifications are possible without departing from the spirit of the present invention.

[0146] For example, in the present embodiment, when the water surface 100 is in a horizontal state, all the wave receiving rotators 3 are provided on the floating body 2 so as to be submerged in the water 102. However, the position where such a wave receiving rotator 3 is provided is not necessarily limited to this. When the water surface 100 is in a horizontal state, it is sufficient that both the wave receiving buckets 32 at at least the first position P1 and the second position P2 are in a state of being submerged in the water 102. In addition, when the wave receiving bucket 32 at the first position P1 is submerged in this way, it is obvious that the wave receiving bucket 32 at the third position P3, which is the point-symmetrical position when the water surface 100 is in a horizontal state, is also in a submerged state.

[0147] Further, in the present embodiment, the shape of the floating body 2 is described by taking the ship shape as an example. However, the shape of the floating body is not necessarily limited to the ship shape. For example, various shapes adopted for floating body structures for offshore wind power generation or other shapes may be adopted.

[0148] Also, in the present embodiment, a speed increaser 41 and a flywheel 42 are adopted as the connection transmission mechanism 4, and these speed increaser 41 and flywheel 42 are interposed between the rotation shaft 33 of the wave receiving rotator 3 and the rotor part 51 of the generator 5 to connect the two. However, the mode of the connection transmission mechanism is not necessarily limited to this.

[0149] For example, in addition to the speed increaser 41 and the flywheel 42, a friction plate type electromagnetic clutch is provided as the connection transmission mechanism. After this electromagnetic clutch is provided between the speed increaser 41 and the flywheel 42, according to the rotation operation of the wave receiving rotator 3, the rotor part 51 of the generator 5, the flywheel 42, and the speed increaser 41 may be connected or the flywheel 42 and the generator 5 (the rotor part 51 thereof) and the speed increaser 41 may be disconnected as appropriate.

[0150] For example, by doing so, when the rotational speed of the flywheel 42 is higher than that of the wave receiving rotor 3, the electromagnetic clutch may be disengaged, and the rotor portion 51 of the generator 5 may be rotated by the rotational inertia force of the flywheel 42 to generate electricity. Also, even when the wave receiving rotor 3 rotates in the reverse direction by chance, the electromagnetic clutch may be disengaged, and the rotor portion 51 of the generator 5 may be rotated by the rotational inertia force of the flywheel 42 to generate electricity.

[0151] Further, according to the friction plate type electromagnetic clutch, the rotational force is transmitted from the driving shaft to the driven shaft through the frictional force between the friction plates that are in contact with each other. By separating such friction plates, the driving shaft side and the driven shaft side are separated, and the transmission of the rotation of the driving shaft to the driven shaft is blocked. Therefore, by adjusting the contact state of such friction plates to a semi-clutch state, the speed increaser 41 and the generator 5 can be smoothly connected. In particular, when there is a speed difference between the rotational speed of the high-speed output shaft 41b of the speed increaser 41 and the rotational speed of the flywheel 42, a smooth connection operation can be performed by connecting both friction plates using the semi-clutch state.

[0152] Also, the embodiment of the connection transmission mechanism is not necessarily limited to the above-described mode. For example, the rotating shaft 33 of the wave receiving rotor 3 may be connected to the low-speed input shaft 41a of the speed increaser 41, and the rotor portion 51 of the generator 5 may be connected to the high-speed output shaft 41b of the speed increaser 41. That is, the rotating shaft 33 of the wave receiving rotor 3 and the rotor portion 51 of the generator 5 may be connected in a mode in which only the speed increaser 41 is interposed therebetween.

[0153] Also, in the present embodiment, the outer shape of the wave receiving bucket 32 is a conical shape, but it is not necessarily limited to the conical shape, and other forms may be used. For example, a frustum shape may be used. Also, the shape of the wave receiving surface is not necessarily limited to a conical concave portion, and any concave shape that can easily receive the relative water flow may be used. For example, it may be a frustum-shaped concave portion, a spherical concave portion, a bowl-shaped concave portion, or other shaped concave portions.

[0154] In addition, in the present embodiment, a total of four receiving wave rotating bodies 3 are provided on the front, rear, left, and right sides of the floating body 2. However, the number of the receiving wave rotating bodies 3 mounted on one such floating body 2 and their arrangement modes are not necessarily limited to this. For example, a number of receiving wave rotating bodies 3 exceeding four in total may be provided for the floating body 2. Further, in the present embodiment, one receiving wave rotating body 3 is provided for each one rotation shaft 33. However, in a different embodiment, for example, two or more receiving wave rotating bodies 3 may be arranged coaxially for one rotation shaft 33.

[0155] In addition, in the present embodiment, one receiving wave rotating body 3 is provided on each of the left and right sides of the bow 21 side and the stern 22 side of the floating body 2. However, in a different embodiment, for example, one receiving wave rotating body 3 may be provided on each of the port side 23 and the starboard side 24 of the entire floating body 2. Further, two or more receiving wave rotating bodies 3 may be arranged in parallel on the same rotation shaft 33 on the port side 23 of the floating body 2, or two or more receiving wave rotating bodies 3 may be arranged in parallel on the same rotation shaft 33 on the starboard side 24 of the floating body 2.

[0156] In addition, in the present embodiment, a total of eight receiving wave buckets 32 are provided for each receiving wave rotating body 3. However, in a different embodiment, for example, a number of receiving wave buckets 32 exceeding eight in total may be provided for the receiving wave rotating body 3.

[0157] In addition, in the second embodiment, the receiving wave member 133 is urged by an urging member to be in a closed state. However, the receiving wave member 133 does not necessarily need to be urged by an urging member, and it may be such that it is opened and closed only by the force of the flow of the relative water flow 103. In this case, when the receiving wave member 133 receives the force of the flow of the relative downstream flow 103A, the receiving wave member 133 is pushed and moved from the open position to the closed position, while when the receiving wave member 133 receives the force of the flow of the relative upstream flow 103B, the receiving wave member 133 is pushed and moved from the closed position to the open position.

Explanation of Reference Numerals

[0158] 1 Wave power generation unit 2 Floating body 3 Wave receiving rotating body 4 Connection transmission mechanism 5 Generator 6 Mooring member 8 Heavy object 31 Rotating main body part 32 Wave receiving bucket 32P1 Wave receiving bucket at the first position 32P2 Wave receiving bucket at the second position 32P3 Wave receiving bucket at the third position 32P4 Wave receiving bucket at the fourth position 32a Tip part 32b, 133a Wave receiving surface 32c Pointed outer peripheral surface 33 Rotating shaft 51 Rotor part 100 Water surface 101 Surface wave 102 Underwater 103 Relative water flow 103a Relative water flow received by the wave receiving surface of the wave receiving bucket at the first position 103b Relative water flow received by the wave receiving surface of the wave receiving bucket at the second position 103c Relative water flow received by the wave receiving surface of the wave receiving bucket at the third position 103d Relative water flow received by the wave receiving surface of the wave receiving bucket at the fourth position 103A Relative downstream flow 103B Relative upstream flow 104 Seabed 130 Wave receiving rotating body of the second embodiment 131 Wave receiving bucket of the second embodiment 131P1 Wave receiving bucket of the second embodiment at the first position 131P2 Wave receiving bucket of the second embodiment at the second position 131P3 Wave receiving bucket of the second embodiment at the third position 131P4 Wave receiving bucket of the second embodiment at the fourth position 132 Bucket main body 132a Base end face (a part of the base end portion of the bucket body) 132a1 Base end opening (a part of the base end portion of the bucket body, a part of the water passage) 132b Water receiving space (a part of the water passage) 132c Tip face (a part of the tip end portion of the bucket body) 132c1 Tip opening (a part of the tip end portion of the bucket body, a part of the water passage) 132d Tip partition wall (a part of the base end portion of the bucket body) 132e Water passage (the water passage) 133 Wave receiving member 133a Wave receiving surface 133b Opening and operating surface 133c Rocking shaft P1 First position P2 Second position P3 Third position P4 Fourth position P Pitch circle

Claims

1. A wave power generation unit for a wave power generation system that generates power using water surface waves generated on an offshore water surface, a floating body that can float on a water surface generating water waves by using buoyancy and that can move in each axis direction of a spatially fixed coordinate system and rotate around each axis in response to the water surface waves, thereby swaying and freely rocking on the water surface; The floating structure is provided with a rotating body that is rotatably supported on the float via a rotating shaft and is integrated with the rotating shaft, a plurality of wave-receiving buckets provided on the entire outer circumference of the rotating body, and a wave-receiving rotor that is formed in a waterwheel shape having a wave-receiving surface formed on each of the wave-receiving buckets and that receives water surface waves, and that uses the rotation of the rotating shaft to rotate a rotor of a generator. The wave receiving rotor is The floating body is floating on the water surface and at least a portion of the wave receiving buckets is submerged in water, The wave receiving bucket in the submerged portion is A wave power generation unit characterized in that at a first position where the wave receiving surface faces downward, and at a second position, rotated from the first position around the axis of the rotating shaft and where the wave receiving surface faces sideways, a relative water flow generated in the water is received by the wave receiving surface, thereby imparting a rotational force to the rotating main body.

2. The plurality of receiving buckets include: the rotors are provided on the rotating body at regular intervals on a pitch circle centered on the axis of the rotating shaft, A pointed end portion of the rotating body that is pointed toward the forward rotation direction of the rotating body; the receiving surface facing away from the tip and having a concave shape toward the tip; 2. The wave power generating unit according to claim 1, further comprising a pointed outer peripheral surface having an outer diameter that gradually decreases from the wave receiving surface toward the pointed end.

3. The receiving bucket is a bucket body provided on the rotating body portion at regular intervals on a pitch circle centered on the axis of the rotating shaft; a tip end of the bucket body facing the forward rotation direction of the rotating body part; a base end portion of the bucket body facing the inversion direction of the rotating body portion, opposite to the tip end portion; a water passage which is a flow path provided penetrating the inside of the bucket body from a base end portion to a tip end portion of the bucket body; an on-off valve formed to be freely movable between one of a closed position in which the water passage is closed and an open position in which the water passage is open, and the other, and comprising a wave receiving surface that receives a relative water flow (hereinafter referred to as a "relative forward flow") flowing relatively from the base end side of the bucket body toward the tip end side thereof at the closed position, and a wave receiving member that receives a relative water flow (hereinafter referred to as a "relative reverse flow") flowing relatively in the opposite direction to the relative forward flow and moves from the closed position to the open position, The wave receiving member is The wave receiving surface receives the relative forward flow at the occlusion position, and converts the force of the relative forward flow into a rotational force for rotating the rotating main body in the forward direction. The wave power generation unit described in claim 1, characterized in that the wave receiving member receives a relative backflow at the blocked position, thereby moving the wave receiving member from the blocked position to the open position to open the water passage, and the relative backflow is allowed to pass through the inside of the bucket body through the opened water passage to escape, thereby reducing the underwater resistance experienced by the bucket body.

4. A wave power generation unit as described in any one of claims 1 to 3, characterized in that one end is anchored to the float and the other end is anchored to the bottom of the water itself or a heavy object placed on the bottom of the water, and a mooring member is provided to moor the float at a fixed location.

5. 4. A wave power generation system comprising: a wave power generation unit according to any one of claims 1 to 3; a power transmission means for transmitting power generated by the wave power generation unit; and a power facility for receiving the power transmitted by the power transmission means.

6. A wave power generation system comprising: a wave power generation unit according to claim 4; a power transmission means for transmitting power generated by the wave power generation unit; and a power facility for receiving the power transmitted by the power transmission means.

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