Wave power engine

Abstract

Provided is a technique for converting the energy of waves and appropriately storing the energy.　This wave power engine 1 converts the swaying of an oceanic moving body to prescribed energy. The wave power engine 1 includes: a first container part 21 that is fixed to an oceanic moving body and that sways in accordance with the swaying of the oceanic moving body; a weight part 3 that is housed in the first container part 21 and is configured to be movable inside the first container, and that thereby moves relative to the first container part; a hydraulic pump 4 that applies pressure to a prescribed fluid using kinetic energy based on the relative motion of the weight part 3; and a pressure accumulation tank 31 that seals the fluid pressurized by the hydraulic pump 4 and thereby accumulates the pressure of the fluid. The weight part 3 pushes in a piston 42 along with the relative motion, whereby the piston 42 slides within a cylinder 41 in the hydraulic pump 4 and pressure is applied to the fluid.

Description

Wave engine

[0001] The present invention relates to a wave engine that converts the motion of a marine vehicle into a predetermined energy source.

[0002] Wave power generation, which generates electricity by utilizing wave energy, has been put to practical use for some time. Known wave power generation methods include a method that directly utilizes the fluid energy of waves, such as a method that generates electricity by driving a turbine with a water current, and a method that generates electricity by converting a water current into the rocking motion of a wave-receiving member. Another known wave power generation method is a method that utilizes the action of waves, such as a method that generates electricity using the kinetic energy of a floating structure that rocks in accordance with the movement of the waves.

[0003] As a method of generating electricity by converting water flow into the rocking motion of a wave-receiving member, for example, Patent Document 1 discloses a technology that generates electricity using a hydraulic motor that is equipped with a wave-receiving member that rocks in response to the force of waves and is operated by hydraulic pressure generated based on the rocking motion of the wave-receiving member.

[0004] Furthermore, as a method of generating electricity using the kinetic energy of a floating structure that sways in accordance with the movement of waves, for example, Patent Document 2 discloses a technology for generating electricity by utilizing the kinetic energy of a weight that is attached inside the floating structure and moves in accordance with fluctuations in the water surface.

[0005] JP 2015-108344 A JP 2012-215120 A

[0006] In conventional methods that directly utilize the fluid energy of waves, for example, in a method that generates electricity by driving a turbine with a water current, it is relatively easy to configure a power generation device by installing a waterway and a turbine in the hull, but these tend to cause resistance to the movement of the hull. Also, in the technology described in Patent Document 1, the durability of the wave-receiving member can easily become an issue because the wave-receiving member is structurally subjected to the water current and swings.

[0007] On the other hand, in a method of generating electricity using the kinetic energy of a floating structure that sways in accordance with the movement of waves, the components of the power generation device are not directly exposed to the water current, so there is little risk of the water current affecting the durability of the components. According to the technology described in Patent Document 2, power can be generated by driving a generator based on the reciprocating linear motion of a weight that moves in accordance with fluctuations in the water surface. However, in order to increase the amount of power generated, a large generator or multiple generators must be used, which tends to increase the cost of the equipment used for wave power generation. Thus, various issues remain with wave power generation that uses wave energy to generate electricity, and there is still room for improvement in the technology for converting wave energy and appropriately storing that energy.

[0008] An object of the present disclosure is to provide a technique for converting wave energy and storing that energy in an appropriate manner.

[0009] The wave engine disclosed herein is a wave engine that is installed on a marine vehicle that is configured to be movable on the sea under its own power or by towing, and that converts the motion of the marine vehicle into a predetermined energy. The wave engine comprises: a first container section that is fixed to the marine vehicle and that moves in accordance with the motion of the marine vehicle; a weight section that is housed inside the first container section and configured to be movable inside the first container section, thereby moving relative to the first container section; a pressurizing section that applies pressure to a predetermined fluid by utilizing kinetic energy based on the relative motion of the weight section; and a pressure accumulating section that seals the fluid pressurized by the pressurizing section and accumulates the pressure of the fluid. The pressurizing section is configured as a hydraulic pump having a cylinder and a piston, and the weight section pushes the piston as it moves relative to the first container section, causing the piston to slide within the cylinder in the hydraulic pump, thereby applying pressure to the fluid.

[0010] The wave engine is a device that converts the motion of a marine vehicle into predetermined energy. Here, the marine vehicle is a vehicle configured to move on the sea under its own power or by towing, such as a ship or a floating marine structure such as a megafloat. In such a wave engine, when the first container section moves in accordance with the motion of the marine vehicle caused by waves, the weight section moves relative to the first container section, and the pressurizing section applies pressure to a predetermined fluid using the resulting kinetic energy. The fluid may be, for example, hydraulic oil usable in hydraulic devices such as hydraulic motors. The fluid pressurized by the pressurizing section is introduced into the pressure accumulator, where the pressure of the fluid is accumulated. This allows the pressure energy of the fluid to be stored in the pressure accumulator. In other words, according to the present disclosure, the kinetic energy of the weight section, which moves relative to the first container section in accordance with the motion of the marine vehicle caused by waves, can be suitably converted into pressure energy of the fluid. This pressure energy can then be stored in the pressure accumulator.

[0011] In the wave engine described above, the weight portion pushes the piston of the hydraulic pump as it moves relative to the hydraulic pump, thereby applying pressure to the fluid. This allows wave energy to be converted in an efficient manner. Furthermore, in the wave engine of the present disclosure, in the above configuration, the weight portion may be formed by a predetermined tank configured to be able to seal a fluid therein, and the fluid pressurized by the pressurizing portion may be sealed in the tank, thereby providing a pressure accumulator in the weight portion. This allows the weight of the tank, which is configured to accumulate the pressure of the fluid, and the weight of the fluid sealed in the tank to be used as energy for pressurizing the fluid, thereby reducing the cost and space of the device used to utilize wave energy.

[0012] In the wave power engine described above, the pressurizing unit may be configured with four hydraulic pumps, each of which is installed at four corners of the first container unit formed into a rectangular parallelepiped, and the first container unit may include a first rail extending in a predetermined first direction and a second rail extending in a second direction perpendicular to the first direction. In this case, when the weight unit moves relative to the first container unit in the first direction as the marine moving vehicle moves, the pistons of one of the two sets of hydraulic pumps facing each other in the first direction may be pushed in due to the relative movement, and the pistons of the other set of hydraulic pumps may be pulled out due to the relative movement. Furthermore, when the weight section moves relative to the first container section in the second direction due to the motion of the marine vehicle, for two sets of hydraulic pumps among the four hydraulic pumps that face each other in the second direction, the pistons of one set of hydraulic pumps may be pushed in due to the relative movement, and the pistons of the other set of hydraulic pumps may be pulled out due to the relative movement.

[0013] Furthermore, in this case, a shaft portion supporting the pressurizing portion may be provided at each of the four corners of the first container portion on which the pressurizing portion is installed, and the pressurizing portion may be rotatably supported on the shaft portion via an insertion hole formed in an end of the cylinder opposite to the piston side, and into which the shaft portion is inserted. Here, the weight portion may have a coupling for connecting to the piston, and the hydraulic pump may have biasing means for biasing the piston toward the coupling, and when the hydraulic pumps are installed at each of the four corners of the first container portion, the coupling and the piston may abut in an unfastened state, allowing the piston to slide relative to the coupling at the abutting surface.

[0014] Such a wave engine may include a second container part mounted vertically upward on the first container part, and in this case, may further include a tube for supplying the fluid filled in the second container part into the cylinder of the hydraulic pump, or may further include a flow path for supplying the fluid filled in the second container part to the first container part.

[0015] According to the present disclosure, wave energy can be converted and the energy can be stored in an advantageous manner.

[0016] Fig. 1 is a diagram showing a schematic configuration of a wave engine in a first embodiment. Fig. 2 is a diagram for explaining a mode of converting wave energy and storing that energy in the first embodiment. Fig. 3 is a diagram for explaining the structure of an accumulator tank. Fig. 4 is a diagram showing a schematic configuration of a wave engine in a second embodiment in comparison with the wave engine in the first embodiment.

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The configurations of the following embodiments are examples, and the present disclosure is not limited to the configurations of the embodiments.

[0018] First Embodiment An overview of a wave engine according to a first embodiment will be described with reference to FIG. 1 . FIG. 1 is a diagram showing the schematic configuration of the wave engine according to this embodiment. The wave engine 1 according to this embodiment is a device that converts the motion of a marine moving body into predetermined energy. Here, the marine moving body is a moving body configured to be able to move on the sea under its own power or by towing, such as a ship or a floating marine structure such as a megafloat. As shown in FIG. 1 , the wave engine 1 is realized by incorporating a predetermined configuration into a container 2. Note that a well-known marine container can be used as the container 2, and the container 2 in this embodiment is a dry container (general-purpose container). FIG. 1( a) is a front view of the wave engine 1, and FIG. 1( b) is a plan view of the wave engine 1. To illustrate the interior of the container 2, one side of the first container section 21 and the second container section 22 is not shown in FIG. 1( a), and the top surfaces of the second container section 22 and the first container section 21 are not shown in FIG. 1( b).

[0019] As shown in Fig. 1 , the wave engine 1 includes a first container section 21 that is fixed to the marine vehicle and sways in accordance with the swaying of the marine vehicle; a weight section 3 that is housed inside the first container section 21 and is configured to be movable inside the first container section 21; a hydraulic pump 4 (pressurizing section of the present disclosure) that applies pressure to a predetermined fluid using the kinetic energy of the weight section 3; and a pressure accumulator tank 31 (pressure accumulator of the present disclosure) that seals the fluid pressurized by the hydraulic pump 4 and accumulates the pressure of the fluid. Here, the fluid in this embodiment is hydraulic oil that can be used in hydraulic devices such as hydraulic motors. However, there is no intention to limit the present disclosure to this example, and the fluid may be a liquid such as water.

[0020] In this embodiment, the second container section 22 is placed vertically upward on the first container section 21. The internal space of the second container section 22 is filled with hydraulic oil, and a tube 23 is provided for supplying the hydraulic oil filled in the second container section 22 into the cylinder 41 of the hydraulic pump 4. In this manner, the hydraulic oil filled in the second container section 22 is supplied into the cylinder 41 of the hydraulic pump 4 via the tube 23.

[0021] As shown in FIG. 1 , the weight section 3 is configured to include an accumulator tank 31 and a housing 32 that is a case that surrounds the accumulator tank 31. In the present embodiment, a plurality of accumulator tanks 31 are housed in the housing 32. Here, as described above, the accumulator tank 31 is a tank that seals the hydraulic oil pressurized by the hydraulic pump 4. That is, in the present embodiment, the weight section 3 is configured by the accumulator tank 31 that is configured to be able to seal the hydraulic oil therein, and the hydraulic oil pressurized by the hydraulic pump 4 is sealed in the accumulator tank 31, thereby providing a pressure accumulator section in the weight section. In this way, the weight of the accumulator tank 31, which is configured to accumulate the pressure of the hydraulic oil, and the weight of the hydraulic oil sealed in the accumulator tank 31 can be used as energy for pressurizing the hydraulic oil, thereby reducing the cost and saving space of the device used to utilize wave energy.

[0022] The weight unit 3 is configured to be movable inside the first container section 21, and thus moves relative to the first container section 21. As shown in FIG. 1 , in this embodiment, the weight unit 3 is arranged on the first arrangement section 213. Here, the first arrangement section 213 is configured to include a first rail 2131 extending in a predetermined first direction. Note that the first direction is, for example, the longitudinal direction of the first container section 21. The weight unit 3 also has a first mover 321 that is fixed in a position facing the first rail 2131 when the weight unit 3 is housed in the first container section 21 and is configured to be horizontally movable along the first rail 2131. The first mover 321 is a roller fixed to the bottom surface of the housing 32. The first mover 321 slides on the first rail 2131 in accordance with the pitching of the marine vehicle, and thus the weight unit 3 moves relative to the first container section 21.

[0023] 1 , a second rail 2141 extending in a second direction perpendicular to the first direction is provided on the bottom surface inside the first container section 21. The first placement section 213 includes a second mover 2132 fixed to a position facing the second rail 2141 and configured to be horizontally movable along the second rail 2141. The second mover 2132 is a roller fixed to the first placement section 213. The second mover 2132 slides on the second rail 2141 in accordance with the pitching of the marine vehicle, causing the weight section 3 to move relative to the first container section 21. With this configuration, as the marine vehicle moves, the first moving element 321 fixed to the weight section 3 (bottom surface of the housing 32) slides on the first rail 2131 of the first placement section 213, and / or the second moving element 2132 fixed to the first placement section 213 in which the weight section 3 is placed slides on the second rail 2141, causing the weight section 3 to move relative to the first container section 21.

[0024] The housing 32 is formed with a confinement section 33 for temporarily sealing in the hydraulic oil to be sealed in the accumulator tank 31, and for introducing the hydraulic oil into the accumulator tank 31. The hydraulic oil from the hydraulic pump 4 is led to the accumulator tank 31 via the confinement section 33. The hydraulic pump 4 and the confinement section 33 are connected by a tube 34.

[0025] The hydraulic pump 4 is a well-known piston pump having a cylinder 41 and a piston 42. In this embodiment, such hydraulic pumps 4 are installed at the four corners (C211 to C214 in FIG. 1B) of the first container section 21. As the weight section 3 moves relative to the first container section 21, the weight section 3 pushes the piston 42, causing the piston 42 to slide within the cylinder 41 and apply pressure to the hydraulic oil. A shaft section 210 that supports the hydraulic pump 4 is provided at the four corners (C211 to C214 in FIG. 1B) of the first container section 21. The hydraulic pump 4 is rotatably supported relative to the shaft section 210 via an insertion hole 412, which is formed in an end section 411 of the cylinder 41 opposite to the piston 42 side, and into which the shaft section 210 is inserted. The piston 42 is connected to the weight section 3 via a coupling 322 fixed to the side surface of the housing 32.

[0026] Next, a mode of converting wave energy and storing that energy, i.e., a mode of storing kinetic energy generated by the motion of the marine vehicle due to waves as hydraulic oil pressure, will be described with reference to Fig. 2. Fig. 2 is a diagram for explaining the mode of converting wave energy and storing that energy in this embodiment. Note that Fig. 2(a) shows a case where the first container section 21 also moves in accordance with the motion of the marine vehicle due to waves, causing the weight section 3 to move relative to the first container section 21 in a first direction, and Fig. 2(b) shows a case where the first container section 21 also moves in accordance with the motion of the marine vehicle due to waves, causing the weight section 3 to move relative to the first container section 21 in a second direction.

[0027] When the weight section 3 moves relative to the first container section 21 in a first direction due to the motion of the marine vehicle, for two sets of hydraulic pumps 4 that face each other in the first direction among the four hydraulic pumps 4, as shown in Figure 2(a), in one set of hydraulic pumps 4 (the hydraulic pumps 4 arranged at C211 and C214), the pistons 42 are pushed in due to the relative movement, and in the other set of hydraulic pumps 4 (the hydraulic pumps 4 arranged at C212 and C213), the pistons 42 are pulled out due to the relative movement.

[0028] At this time, the hydraulic pump 4 rotates relative to the shaft portion 210 as the weight portion 3 moves. As described above, the hydraulic pump 4 has an insertion hole 412 formed in the end portion 411 of the cylinder 41 opposite the piston 42 side, and the insertion hole 412 and the shaft portion 210 are connected via a rolling bearing. As the weight portion 3 moves, the coupling 322 fixed to the side of the housing 32 presses the piston 42 of the hydraulic pump 4 arranged in C211, causing the hydraulic pump 4 to rotate toward C214 while the piston 42 is pushed in. Similarly, the hydraulic pump 4 arranged in C214 rotates toward C211 while the piston 42 is pushed in. Here, when the hydraulic pumps 4 are installed at the four corners of the first container portion 21, the couplings 322 and the pistons 42 abut in an unfastened state, allowing the pistons 42 to slide relative to the coupling 322 on the abutting surfaces. This allows the piston 42 to slide relative to the cylinder 41 and the hydraulic pump 4 itself to rotate in the hydraulic pump 4. Note that a lubricant such as silicon may be applied to each of the contact surfaces of the coupling 322 and the piston 42.

[0029] Meanwhile, at this time, in the hydraulic pumps 4 arranged at C212 and C213, the pistons 42 are pulled out as the weight section 3 moves. Here, the hydraulic pumps 4 have springs that urge the pistons 42 in the direction of pulling them out, and when the weight section 3 moves as described above, the springs urge the pistons 42 towards the coupling 322. As a result, the hydraulic pump 4 arranged at C212 rotates towards the C211 side as its piston 42 is pulled out, and the hydraulic pump 4 arranged at C213 rotates towards the C214 side as its piston 42 is pulled out.

[0030] Furthermore, when the weight section 3 moves relative to the first container section 21 in the second direction due to the motion of the marine vehicle, for two sets of hydraulic pumps 4 that face each other in the second direction among the four hydraulic pumps 4, as shown in Figure 2(b), in one set of hydraulic pumps 4 (the hydraulic pumps 4 arranged at C211 and C212), which is the third set, the pistons 42 are pushed in due to the relative movement, and in the other set of hydraulic pumps 4 (the hydraulic pumps 4 arranged at C213 and C214), which is the fourth set, the pistons 42 are pulled out due to the relative movement.

[0031] In detail, the hydraulic pump 4 arranged at C211 rotates toward the C212 side while its piston 42 is pushed in, and the hydraulic pump 4 arranged at C212 rotates toward the C211 side while its piston 42 is pushed in. On the other hand, the hydraulic pump 4 arranged at C213 rotates toward the C212 side while its piston 42 is pulled out, and the hydraulic pump 4 arranged at C214 rotates toward the C211 side while its piston 42 is pulled out.

[0032] As described above, when the first container section 21 also sways in accordance with the swaying of the marine vehicle caused by waves and the weight section 3 moves relative to the first container section 21 in the first direction, the pistons 42 are pushed in by the relative movement, for example, in the first set of hydraulic pumps 4 arranged at C211 and C214 and the third set of hydraulic pumps 4 arranged at C211 and C212. In this way, pressure can be applied to the hydraulic oil by utilizing the kinetic energy based on the relative movement of the weight section 3, and thus the kinetic energy of the weight section 3, which moves relative to the first container section 21 in accordance with the swaying of the marine vehicle caused by waves, can be suitably converted into pressure energy of the hydraulic oil.

[0033] Here, hydraulic oil pressurized by the hydraulic pump 4 is guided to the sealed portion 33 via the tube 34. A check valve is provided at the connection between the cylinder 41 and the tube 34, restricting the flow of hydraulic oil through the tube 34 to one direction, from the cylinder 41 to the sealed portion 33. Then, hydraulic oil from the hydraulic pump 4 is guided to the accumulator tank 31 via the sealed portion 33. This will be explained with reference to FIG. 3. FIG. 3 is a diagram for explaining the structure of the accumulator tank 31. As shown in FIG. 3( a), when no hydraulic oil is supplied to the accumulator tank 31, the accumulator tank 31 is occupied by a gas bag 313 filled with a gas such as nitrogen. Then, when the hydraulic oil from the sealed portion 33 is guided to the accumulator tank 31 via the tube 311, the hydraulic oil is filled so as to compress the gas bag 313, as shown in FIG. 3( b). Here, a check valve 312 is provided at the connection between the tube 311 and the accumulator tank 31, and prevents the hydraulic oil from flowing back into the tube 311 even when the accumulator tank 31 has been filled with hydraulic oil, as shown in Figure 3(c). This allows the pressure energy of the hydraulic oil to be stored in the accumulator tank 31.

[0034] On the other hand, when the weight section 3 moves relative to the first container section 21 in the first direction, the pistons 42 are pulled out in accordance with this relative movement, for example, in the second set of hydraulic pumps 4 arranged at C212 and C213 and the fourth set of hydraulic pumps 4 arranged at C213 and C214. This increases the volume within the cylinders 41, and the hydraulic oil filled in the second container section 22 is supplied into the cylinders 41 of the hydraulic pumps 4 via the tubes 23. A check valve is provided at the connection between the cylinders 41 and the tubes 23, and the flow of hydraulic oil through the tubes 23 is limited to one direction, from the second container section 22 to the cylinders 41.

[0035] In the above description, the second container section 22 is loaded vertically upward relative to the first container section 21. However, the first container section 21 and the second container section 22 may be disposed apart from each other. In this case, for example, the first container section 21 equipped with the weight section 3 may be disposed at the bottom of the marine vehicle. In this case, the relatively heavy first container section 21 serves as ballast, lowering the center of gravity of the marine vehicle. In this case, the second container section 22 may be disposed in any location, and as described above, hydraulic oil filled in the second container section 22 may be supplied to the cylinder 41 of the hydraulic pump 4 via the tube 23.

[0036] The wave power engine 1 described above can suitably convert the kinetic energy of the weight section 3, which moves relative to the first container section 21 as the marine moving body is rocked by waves, into pressure energy of the hydraulic oil. This pressure energy can then be stored in the accumulator tank 31. In other words, according to the present disclosure, wave energy can be converted and suitably stored.

[0037] In this embodiment, the pressure energy stored in the accumulator tank 31 may be used to generate power. For example, the hydraulic oil stored in the accumulator tank 31 may be supplied to a known hydraulic motor to extract shaft power, and the shaft power may be input to a known generator to generate power. The pressure energy stored in the accumulator tank 31 may also be used to drive a hydraulic machine. Using the high-pressure hydraulic oil stored in the accumulator tank 31 as a drive source for the machine allows the machine to produce a large output at a relatively high speed.

[0038] Furthermore, by installing the above-described wave engine on an offshore floating structure such as a megafloat, an offshore resource factory can be realized. Seawater contains sodium chloride and magnesium chloride, so hydrochloric acid and magnesium can be produced by electrolyzing seawater. Therefore, energy from the wave engine can be used to generate electricity, and the electricity is used to electrolyze seawater to produce hydrochloric acid and magnesium. The generated hydrochloric acid and magnesium can then be transported to land and used as fuel for fuel cells and gas engines. For example, in a gas engine system fueled by hydrochloric acid and magnesium, hydrogen can be generated by injecting granulated magnesium into the hydrochloric acid, and the hydrogen can be burned to drive the gas engine. Such a gas engine system can be used, for example, as a range extender for electric vehicles. Gas engine systems fueled by hydrochloric acid and magnesium tend to continuously produce relatively low power. Therefore, this output can be used to generate electricity using a generator, which can then be used to charge a battery, thereby extending the range of the electric vehicle. Furthermore, by further installing the above-mentioned hydrochloric acid and magnesium generating device on a ship equipped with a wave engine, the generated hydrochloric acid and magnesium can be used as fuel for the ship's power source.

[0039] Furthermore, in the above-mentioned factory, a seawater desalination system may be operated using energy from the wave engine. Here, if a reverse osmosis membrane system is used for the seawater desalination system, high pressure can be applied to the seawater by using the pressure of the fluid stored in the pressure storage unit of the wave engine (for example, by driving a piston using this pressure), thereby allowing only the pure water in the seawater to pass through the osmosis membrane to obtain fresh water. In this case, the seawater desalination system is operated using pressure energy converted from wave energy, so the desalination system can be operated semi-permanently. In a similar manner, a filtration system that filters contaminants contained in seawater may be operated using energy from the wave engine.

[0040] Furthermore, by installing the wave engine described above on a floating breakwater, a breakwater that can convert wave energy and store that energy can be realized. Such a floating breakwater can provide wave protection near quays where waves are strong, and can also store a large amount of energy from strong waves.

[0041] Furthermore, the pressure accumulator of the wave engine may be transported to land, and the pressure of the fluid stored in the pressure accumulator may be utilized to realize a resource factory on land. In such a resource factory, for example, bio-coke or ammonia may be produced. Bio-coke production requires placing raw plant material under high temperature and pressure. By utilizing the high pressure resulting from the pressure of the fluid stored in the pressure accumulator and the high temperature achieved by electricity generated using the pressure of the fluid stored in the pressure accumulator, zero-emission fuel can be produced from renewable energy. Ammonia production requires reacting nitrogen and hydrogen with an iron oxide catalyst at high temperature and high pressure. By obtaining high temperature and high pressure from the pressure accumulator of the wave engine in a similar manner, ammonia can be produced from renewable energy. The ammonia produced in this manner can be used, for example, as fuel for gas turbines and fuel cells.

[0042] Furthermore, by installing the wave engine described above on a floating structure such as a megafloat and further installing a plurality of computers connected to a network on the floating structure, an offshore information processing facility can be realized. In such an information processing facility, energy from the wave engine can be used to generate electricity, which can then be used to operate the computers. Furthermore, such an information processing facility may also be used for, for example, mining virtual currencies.

[0043] Second Embodiment In the above-described first embodiment, an example has been described in which the hydraulic oil filled in the second container portion 22 is supplied into the cylinder 41 of the hydraulic pump 4 via the tube 23. In contrast to this, in the present embodiment, the hydraulic oil filled in the second container portion 22 is first supplied to the first container portion 21. Then, the hydraulic oil in the first container portion 21, which has been made liquid-tight, is supplied into the cylinder 41 of the hydraulic pump 4. This will be described with reference to FIG.

[0044] Fig. 4 is a diagram showing a schematic configuration of the wave power engine of this embodiment in comparison with the wave power engine of the first embodiment. Here, in Fig. 4, hydraulic oil is represented by diagonal lines.

[0045] As shown in Fig. 4(a), in the wave power engine 1 according to the first embodiment, the hydraulic oil filled in the second container portion 22 is supplied into the cylinder 41 of the hydraulic pump 4 via a tube 23. In contrast, in the wave power engine 1 according to the present embodiment, as shown in Fig. 4(b), a flow path 24 is provided for supplying the hydraulic oil filled in the second container portion 22 to the first container portion 21, and the hydraulic oil filled in the second container portion 22 is supplied to the first container portion 21 via the flow path 24 by gravity. In this way, the internal space of the first container portion 21 can serve as a liquid chamber that is maintained in a liquid-tight state with the hydraulic oil.

[0046] When the internal space of the first container section 21 is made liquid-tight with hydraulic oil, hydraulic oil around the cylinder 41 is supplied into the cylinder, for example, through a supply hole formed in the cylinder 41.

[0047] When the hydraulic oil is guided from the hydraulic pump 4 to the accumulator tank 31, the amount of hydraulic oil in the first container portion 21 decreases. Therefore, in this embodiment, the opening and closing of the solenoid valve 241 is controlled so that the inside of the first container portion 21 can be maintained in a liquid-tight state with the hydraulic oil.

[0048] <Other Modifications> The above-described embodiment is merely an example, and the present disclosure may be modified as appropriate within the scope of the gist thereof. For example, the processes and means described in the present disclosure may be freely combined and implemented as long as no technical contradiction occurs.

[0049] REFERENCE SIGNS LIST 1 Wave power engine 2 Container 21 First container section 22 Second container section 3 Weight section 31 Accumulator tank 32 Housing 4 Hydraulic pump 41 Cylinder 42 Piston

Claims

1. A wave engine that is installed on an offshore mobile body configured to be able to move on the sea under its own power or by towing, and converts the motion of the offshore mobile body into a predetermined energy, comprising: a first container section that is fixed to the offshore mobile body and moves in accordance with the motion of the offshore mobile body; a weight section that is housed inside the first container section and configured to be able to move inside the first container section, thereby performing relative motion with respect to the first container section; a pressurizing section that applies pressure to a predetermined fluid by utilizing kinetic energy based on the relative motion of the weight section; and a pressure accumulating section that accumulates the pressure of the fluid by sealing the fluid pressurized by the pressurizing section, wherein the pressurizing section is constituted by a hydraulic pump having a cylinder and a piston, and the weight section pushes the piston in conjunction with the relative motion, causing the piston to slide within the cylinder in the hydraulic pump and applying pressure to the fluid; and the pressurizing section is constituted by four hydraulic pumps, each of which is disposed at one of the four corners of the first container section formed into a rectangular parallelepiped, the first container section is configured to include a first rail extending in a predetermined first direction and a second rail extending in a second direction perpendicular to the first direction, and when the weight section moves relative to the first container section in the first direction as the offshore moving body moves, for two sets of hydraulic pumps among the four hydraulic pumps that face each other in the first direction, the pistons of one of the hydraulic pump sets are pushed in with the relative motion and the pistons of the other hydraulic pump set are pulled out with the relative motion, and when the weight section moves relative to the first container section in the second direction as the offshore moving body moves, for two sets of hydraulic pumps among the four hydraulic pumps that face each other in the second direction, the pistons of one of the hydraulic pump sets are pushed in with the relative motion and the pistons of the other hydraulic pump set are pulled out with the relative motion. A wave power engine.

2. A wave engine as described in claim 1, wherein a shaft portion supporting the pressurizing portion is provided at each of the four corners of the first container portion on which the pressurizing portion is installed, and the pressurizing portion is supported rotatably relative to the shaft portion via an insertion hole formed at the end of the cylinder opposite to the piston side, into which the shaft portion is inserted.

3. A wave engine as described in claim 2, wherein the weight portion has a coupling for connecting with the piston, the hydraulic pump has a biasing means for biasing the piston towards the coupling, and when each of the hydraulic pumps is installed at the four corners of the first container portion, the coupling and the piston abut in an unfastened state, so that the piston is configured to slide relative to the coupling at the abutment surface.

4. A wave engine as described in any one of claims 1 to 3, further comprising: a second container section loaded vertically upward on the first container section; and a tube that supplies the fluid filled in the second container section into the cylinder of the hydraulic pump.

5. A wave engine as claimed in any one of claims 1 to 3, further comprising: a second container section stacked vertically upward on the first container section; and a flow path for supplying the fluid filled in the second container section to the first container section.

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