A hydraulic system for autonomous power generation of a buoy driven by ocean temperature difference and its working method

Abstract

The present invention relates to an ocean temperature difference energy driven buoy autonomous power generation hydraulic system and its working method, belonging to the technical field of hydraulic systems. The power generation hydraulic system includes a rubber bladder, an accumulator, a pilot control valve group, a turbine shaft assembly, a generator, an oil tank, an upper pressure-resistant shell, a lower pressure-resistant shell and an integrated end cover, wherein the upper pressure-resistant shell and the lower pressure-resistant shell are sealed and connected by an integrated end cover, the upper side of the integrated end cover is provided with a pilot control valve group, a turbine shaft assembly and an oil tank, the turbine shaft assembly is connected to a generator, a rubber bladder is provided on the lower side of the integrated end cover, an accumulator is provided in the rubber bladder, the space between the accumulator and the rubber bladder is filled with hydraulic oil, and the space between the rubber bladder and the lower pressure-resistant shell is filled with a phase change medium. The present invention designs a pilot control valve group, the opening pressure is set by an external mechanical spring, the oil circuit is automatically opened after the opening pressure is reached, and the energy loss between the inlet and outlet of the oil is extremely small, which has the advantages of no power consumption and low failure rate.

Description

Technical Field

[0001] The invention relates to an ocean temperature difference energy driven buoy autonomous power generation hydraulic system and a working method thereof, belonging to the technical field of hydraulic systems. Background Art

[0002] The power supply capacity of deep-sea exploration equipment, such as buoys and gliders, is a technical bottleneck that limits their ability to carry out long-term, high-frequency sampling. The temperature difference power supply technology that uses the volume difference between the melting and solidification of phase change materials (PCM) between deep and surface seawater to generate electricity is an ideal energy form for self-sufficiency in electrical energy during the exploration process. Usually, the energy must be stored in an accumulator first. After reaching a predetermined pressure, the controller sends a command to open the switch valve to allow the hydraulic oil to drive the hydraulic motor to rotate, thereby driving the generator to generate electricity.

[0003] However, the current hydraulic motors, switch valves, and hydraulic pipelines usually use finished components in the industrial hydraulic field. After the switch valve is opened, its coil still needs to be powered continuously to allow the electromagnet to overcome the spring force until the power generation process is completed, the coil is powered off, and the valve core is reset under the action of the spring. Therefore, some electrical energy needs to be consumed to complete the power generation process.

[0004] Secondly, traditional hydraulic components such as hydraulic motors and valves have low integration and low mechanical efficiency, resulting in low power generation efficiency of the whole machine, requiring a large number of pipeline connections, resulting in large module mass and high energy consumption, making it difficult to achieve energy self-sufficiency. For this reason, the present invention is proposed. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides an ocean temperature difference energy-driven buoy autonomous power generation hydraulic system, which eliminates the traditional electromagnetic switching valve and reduces the power consumption of the driving valve; the provision of a turbine shaft direct drive module simplifies the traditional hydraulic motor structure and reduces the energy transfer efficiency loss; at the same time, the various components are arranged on an integrated end cover to reduce the risk of hydraulic pipeline leakage, and the integrated design reduces the weight of the entire machine, which is conducive to further improving the movement flexibility of the profile buoy.

[0006] The present invention also provides a working method of the above-mentioned ocean temperature difference energy driven buoy autonomous power generation hydraulic system.

[0007] The technical solution of the present invention is as follows:

[0008] A marine temperature difference energy driven buoy autonomous power generation hydraulic system, including a rubber bladder, an accumulator, a pilot control valve group, a turbine shaft assembly, a generator, an oil tank, an upper pressure-resistant shell, a lower pressure-resistant shell and an integrated end cover, wherein:

[0009] The upper pressure-resistant shell and the lower pressure-resistant shell are sealed and connected by an integrated end cover. A pilot control valve group, a turbine shaft assembly and an oil tank are arranged on the upper side of the integrated end cover. The turbine shaft assembly is connected to a generator. A rubber bladder is arranged on the lower side of the integrated end cover. An accumulator is arranged in the rubber bladder. The space between the accumulator and the rubber bladder is filled with hydraulic oil. The space between the rubber bladder and the lower pressure-resistant shell is filled with a phase change working medium.

[0010] According to the preferred embodiment of the present invention, the accumulator includes an outer shell, an isolation piston and an air-filled end cover, the air-filled end cover is fixedly arranged at the bottom of the outer shell, the isolation piston is slidably arranged in the middle of the outer shell, and radial oil holes are arranged at the top of the outer shell to facilitate the entry and exit of hydraulic oil, and the closed space between the isolation piston and the air-filled end cover is filled with nitrogen. When the oil pressure at the upper end is higher than the pressure in the air cavity at the lower end, the isolation piston moves downward, compresses the nitrogen, and the air cavity pressure increases until the air pressure is equal to the oil pressure. When the oil pressure decreases, the isolation piston moves upward.

[0011] According to a further preferred embodiment of the present invention, a step surface is provided on the upper portion of the outer shell to limit the maximum stroke of the isolation piston.

[0012] Preferably according to the present invention, the pilot control valve group includes a main valve core, a main spring, a main valve end cover, a valve body, a pilot spring and a pilot valve core, wherein the outer wall of the valve body is arranged in the integrated end cover through a thread, the main valve end cover is fixedly arranged at one end of the valve body, a pilot spring is arranged in the valve body, one side of the pilot spring is connected to the pilot valve core, the pilot valve core contacts the inner side of the main valve end cover, the outer side of the main valve end cover is connected to the main valve core through the main spring, and an annular groove is arranged on the outer wall of the main valve core.

[0013] Preferably, according to the present invention, a first oil passage connected to the accumulator is provided in the integrated end cover at the lower side of the main valve core, a second oil passage is provided on one side of the first oil passage, the lower side of the second oil passage is connected to the accumulator, the upper side of the second oil passage is respectively connected to the oil tank and the main valve core, a one-way valve is provided at the connection position between the second oil passage and the oil tank, a third oil passage is provided in the integrated end cover at the upper side of the main valve core, and the oil discharged from the third oil passage flows to the turbine shaft assembly;

[0014] An oil drain port is built into the upper side of the valve body, which connects the inner cavity of the valve body and the third oil channel. An axial damping hole connected to the second oil channel is provided on one side of the main valve core, and a penetrating radial damping hole is provided on the top of the main valve core. The inside of the main valve core is an oil chamber, and the main valve end cover is connected to the oil chamber.

[0015] Preferably, according to the present invention, an adjusting knob is provided on one side of the valve body away from the pilot valve core, one end of the adjusting knob is threadedly connected to the valve body, and the other end is connected to the pilot spring, and the pre-compression amount of the pilot spring is adjusted by rotating the adjusting knob.

[0016] Preferably, according to the present invention, the turbine shaft assembly is arranged in the through hole at the top of the integrated end cover, the turbine shaft assembly includes a guide cover, a turbine shaft and a valve block end cover, blades are arranged axially and obliquely on the side wall of the turbine shaft, the lower end of the turbine shaft is connected to the guide cover through a bearing A, the upper end of the turbine shaft is connected to the valve block end cover through a bearing B, the guide cover and the valve block end cover are arranged in the through hole, the top of the turbine shaft is connected to a generator, the upper space of the turbine shaft is connected to an oil tank through a fourth oil channel, and the space between the lower part of the turbine shaft and the guide cover is the fifth oil channel.

[0017] According to a further preferred embodiment of the present invention, a threaded groove connected to the turbine shaft is provided in the middle of the guide cover plate, and a plurality of inclined oil holes are provided around the circumference of the guide cover plate so that the oil enters the fifth oil passage at a certain angle;

[0018] The diameter of the circle surrounded by the blades is the same as the diameter of the through hole at the top of the integrated end cover.

[0019] The working method of the above-mentioned ocean temperature difference energy driving buoy autonomous power generation hydraulic system is as follows:

[0020] (1) The power generation hydraulic system is installed on the buoy. When it floats to the surface warm seawater, the seawater temperature is higher than the melting temperature of the phase change medium. The phase change medium expands due to heat, and the hydraulic oil in the rubber bladder is forced to reduce in volume and flows out through the radial oil hole to the upper chamber of the accumulator, pushing the isolation piston downward, compressing the volume of nitrogen, and increasing the oil pressure at the upper end of the accumulator. Due to the one-way valve, the hydraulic oil cannot flow back into the oil tank and can only apply pressure to the pilot control valve group.

[0021] When the pressure rises to the point where the pilot control valve group is fully opened, the isolation piston moves upward due to the reduction of upper pressure, pushing the hydraulic oil into the fifth oil passage after changing the incident angle through the guide cover plate, pushing the turbine shaft to rotate, driving the generator to generate electricity, and the hydraulic oil flowing through the turbine shaft enters the oil tank through the fourth oil passage, causing the pressure in the oil tank to rise, and the oil pressure in the fourth oil passage is extremely low;

[0022] When the upper part of the isolation piston contacts the step surface inside the outer shell and stops moving, the hydraulic oil pressure on the upper part of the accumulator no longer changes, and the oil inside the main valve core no longer flows. According to Pascal's principle, the oil pressure on both sides is equal and the effective area is equal. Since the built-in main spring is in a compressed state, the force provided resets the main valve core, that is, the oil port of the pilot control valve group is closed;

[0023] (2) When the buoy dives into the deep cold seawater, the expanded phase-change medium begins to solidify and shrinks in volume. At this time, the pressure in the rubber bladder drops to 0 or negative pressure, which is less than the pressure in the oil tank, that is, the pressure on the left side of the one-way valve is less than the pressure on the right side. The main valve core opens, and the oil in the oil tank is replenished into the cavity between the rubber bladder and the accumulator through the one-way valve until the phase-change medium is completely solidified. The volume no longer changes, and the hydraulic oil no longer flows, waiting for the next buoyancy. When the phase-change medium melts, it re-enters the next working cycle.

[0024] According to the present invention, the working process of the pilot control valve group is further preferably as follows:

[0025] When the pressure in the oil chamber of the main valve core does not reach the set pressure, the pilot valve core is in a normally closed state under the action of the pilot spring, and the pressures of the first oil channel and the second oil channel are equal. When the main valve core does not move, the axial damping hole connects the oil chamber and the second oil channel. According to Pascal's principle, the pressures at the left and right ends of the main valve core are equal, and the effective areas are equal, so the main valve core does not move;

[0026] When the pressure in the oil chamber increases to overcome the spring force of the pilot spring, the pilot valve core moves to the left, and the hydraulic oil flows through the oil drain port into the third oil channel. At this time, the hydraulic oil in the main valve core flows. According to Bernoulli's theorem, due to the effect of the small damping hole, the pressure in the oil chamber decreases, and the pressure difference between the left and right sides of the main valve core increases, pushing the main valve core and the main spring to move to the left, and the annular groove moves to the left accordingly, connecting the first oil channel with the third oil channel. At the same time, due to the leftward movement of the main valve core, the radial damping hole connects the oil in the oil chamber with the third oil channel. The stiffness of the main spring is extremely small, and it only plays a reset role. Under the action of oil pressure, the main valve core moves to the left to the limit position, the opening between the first oil channel and the third oil channel is the largest, and the throttling effect is the smallest.

[0027] The beneficial effects of the present invention are:

[0028] 1. The present invention eliminates the traditional electromagnetic switch valve between the accumulator outlet and the generator, and adds a pilot control valve group. The opening pressure is set by an external mechanical spring. When the opening pressure is reached, the oil circuit is automatically opened, and the energy loss between the inlet and outlet oil ports is extremely small. Compared with the electrically controlled electromagnetic switch valve solution, the present invention has the advantages of no power consumption and low failure rate.

[0029] 2. In order to solve the problems of large overall mass and high energy consumption of heave and sink motion caused by the large number of components and heavy shell of traditional hydraulic motors, the present invention proposes an integrated turbine shaft structure. High-pressure oil directly drives the turbine shaft to rotate and drive the generator to generate electricity. The simplified structure reduces the mechanical efficiency loss caused by the coaxiality error between components.

[0030] 3. The present invention integrates the accumulator oil outlet, control element, power generation element and oil tank inlet and outlet into one valve block, all of which are connected through internal oil channels, so that the pressure-resistant casing in the high-pressure area is shared, reducing the weight of the whole machine; the external hydraulic pipeline is eliminated, solving the problem of large space occupied by the external pipeline and high risk of leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention;

[0032] Figure 2 It is a cross-sectional structural schematic diagram of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the accumulator of the present invention;

[0034] Figure 4 This is a cross-sectional structural diagram of the pilot control valve group of the present invention.

[0035] Figure 5 It is a schematic diagram of the main valve core structure of the present invention;

[0036] Figure 6 It is a schematic diagram of the structure of the adjustment knob of the present invention;

[0037] Figure 7 It is a schematic diagram of the cross-sectional structure of the integrated end cover of the present invention;

[0038] Figure 8 It is a schematic diagram of the turbine shaft structure of the present invention;

[0039] Fig. 9 It is a schematic diagram of the structure of the guide cover plate of the present invention;

[0040] Among them: 1. Phase change working fluid; 2. Hydraulic oil; 3. Accumulator; 4. Pilot control valve group; 5. Turbine shaft assembly; 6. Generator; 7. Oil tank; 8. Check valve; 9. Upper pressure-resistant shell; 10. Battery; 11. Integrated end cover; 12. Rubber bladder; 13. Lower pressure-resistant shell;

[0041] 301, outer shell; 302, radial oil hole; 303, isolation piston; 304, inflation end cover;

[0042] 401, main valve core; 402, main spring; 403, main valve end cover; 404, pilot valve core; 405, pilot spring; 406, adjusting knob; 407, valve body;

[0043] 4011, axial damping hole; 4012, oil chamber; 4013, annular groove; 4014, radial damping hole;

[0044] 4031, oil drain port;

[0045] 501, guide cover plate; 502, bearing A; 503, turbine shaft; 504, bearing B; 505, valve block end cover;

[0046] 1101, first oil channel; 1102, second oil channel; 1103, third oil channel; 1104, fourth oil channel; 1105, fifth oil channel. DETAILED DESCRIPTION

[0047] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings, but is not limited thereto.

[0048] Embodiment 1:

[0049] like Figure 1-Figure 9 As shown, this embodiment provides an ocean temperature difference energy driven buoy autonomous power generation hydraulic system, including a rubber bladder 12, an accumulator 3, a pilot control valve group 4, a turbine shaft assembly 5, a generator 6, an oil tank 7, an upper pressure-resistant shell 9, a lower pressure-resistant shell 13 and an integrated end cover 11, wherein:

[0050] The upper pressure-resistant shell 9 and the lower pressure-resistant shell 13 are sealed and connected by an integrated end cover 11. A pilot control valve group 4, a turbine shaft assembly 5 and an oil tank 7 are arranged on the upper side of the integrated end cover 11. The turbine shaft assembly 5 is connected to a generator 6, and the generator 6 is connected to a battery 10. A rubber bladder 12 is arranged on the lower side of the integrated end cover 11. An accumulator 3 is arranged in the rubber bladder 12. The space between the accumulator 3 and the rubber bladder 12 is filled with hydraulic oil 2. The space between the rubber bladder 12 and the lower pressure-resistant shell 13 is filled with a phase change working medium 1.

[0051] The accumulator 3 includes an outer shell 301, an isolation piston 303 and an air charging end cover 304. The air charging end cover 304 is fixedly arranged at the bottom of the outer shell 301, and the isolation piston 303 is slidably arranged in the middle of the outer shell 301. The top of the outer shell 301 is provided with a radial oil hole 302 to facilitate the entry and exit of hydraulic oil. The closed space between the isolation piston 303 and the air charging end cover 304 is filled with nitrogen. When the oil pressure at the upper end is higher than the pressure in the air cavity at the lower end, the isolation piston 303 moves downward to compress the nitrogen, and the air cavity pressure increases until the air pressure is equal to the oil pressure. When the oil pressure decreases, the isolation piston 303 moves upward.

[0052] The upper portion of the outer shell 301 is provided with a step surface to limit the maximum stroke of the isolation piston.

[0053] The pilot control valve group 4 includes a main valve core 401, a main spring 402, a main valve end cover 403, a valve body 407, a pilot spring 405 and a pilot valve core 404, wherein the outer wall of the valve body 407 is arranged in the integrated end cover 11 through a thread, the main valve end cover 403 is fixedly arranged at one end of the valve body 407, a pilot spring 405 is arranged in the valve body 407, one side of the pilot spring 405 is connected to the pilot valve core 404, the pilot valve core 404 contacts the inner side of the main valve end cover 403, the outer side of the main valve end cover 403 is connected to the main valve core 401 through the main spring 402, and an annular groove 4013 is arranged on the outer wall of the main valve core 401.

[0054] A first oil passage 1101 connected to the accumulator 3 is provided in the integrated end cover 11 at the lower side of the main valve core 401, a second oil passage 1102 is provided on one side of the first oil passage 1101, the lower side of the second oil passage 1102 is connected to the accumulator 3, the upper side of the second oil passage 1102 is respectively connected to the oil tank 7 and the main valve core 401, a one-way valve 8 is provided at the connection position between the second oil passage 1102 and the oil tank 7, a third oil passage 1103 is provided in the integrated end cover 11 at the upper side of the main valve core 401, and the third oil passage 1103 discharges oil to flow to the turbine shaft assembly 5;

[0055] An oil drain port 4031 is built into the upper side of the valve body 407, and the oil drain port 4031 connects the inner cavity of the valve body 407 and the third oil channel 1103. An axial damping hole 4011 connected to the second oil channel 1102 is provided on one side of the main valve core 401, and a penetrating radial damping hole 4014 is provided on the top of the main valve core 401. The interior of the main valve core 401 is an oil chamber 4012, and the main valve end cover 403 is connected to the oil chamber 4012.

[0056] An adjusting knob 406 is provided on one side of the valve body 407 away from the pilot valve core 404 . One end of the adjusting knob 406 is threadedly connected to the valve body 407 , and the other end is connected to the pilot spring 405 . The pre-compression amount of the pilot spring 405 is adjusted by rotating the adjusting knob 406 .

[0057] The turbine shaft assembly 5 is arranged in the through hole at the top of the integrated end cover 11. The turbine shaft assembly 5 includes a guide cover plate 501, a turbine shaft 503 and a valve block end cover 505. Blades are arranged axially and obliquely on the side wall of the turbine shaft 503. The lower end of the turbine shaft 503 is connected to the guide cover plate 501 through a bearing A502, and the upper end of the turbine shaft 503 is connected to the valve block end cover 505 through a bearing B504. The guide cover plate 501 and the valve block end cover 505 are arranged in the through hole, and the top of the turbine shaft 503 is connected to the generator 6. The upper space of the turbine shaft 503 is connected to the oil tank 7 through the fourth oil passage 1104, and the space between the lower part of the turbine shaft 503 and the guide cover plate 501 is the fifth oil passage 1105.

[0058] A threaded groove connected to the turbine shaft 503 is provided in the middle of the guide cover plate 501, and a plurality of inclined oil holes are provided around the guide cover plate 501 so that the oil enters the fifth oil passage 1105 at a certain angle;

[0059] The diameter of the circle formed by the blades is the same as the diameter of the through hole at the top of the integrated end cover 11 .

[0060] The working method of the above-mentioned ocean temperature difference energy driving buoy autonomous power generation hydraulic system is as follows:

[0061] (1) The power generation hydraulic system is installed on the buoy. When it floats to the surface warm seawater, the seawater temperature is higher than the melting temperature of the phase change medium. The phase change medium 1 expands due to the heat, and the hydraulic oil in the rubber bladder 12 is forced to reduce in volume and flows out through the radial oil hole 302 to the upper chamber of the accumulator 3, pushing the isolation piston 303 downward, compressing the volume of nitrogen, and increasing the oil pressure at the upper end of the accumulator 3. Due to the one-way valve 8, the hydraulic oil cannot flow back into the oil tank 7 and can only apply pressure to the pilot control valve group 4.

[0062] When the pressure rises to the point where the pilot control valve group 4 is fully opened, the isolation piston 303 moves upward due to the decrease in upper pressure, pushing the hydraulic oil to enter the fifth oil passage 1105 after changing the incident angle through the guide cover plate 501, pushing the turbine shaft 503 to rotate, driving the generator 6 to generate electricity, and the hydraulic oil flowing through the turbine shaft 503 enters the oil tank 7 through the fourth oil passage 1104, causing the pressure in the oil tank 7 to rise, and the oil pressure in the fourth oil passage 1104 is extremely low;

[0063] When the upper part of the isolation piston 303 contacts the step surface in the outer shell 301 and stops moving, the hydraulic oil pressure in the upper part of the accumulator 3 no longer changes, and the oil in the main valve core 401 no longer flows. According to Pascal's principle, the oil pressure on both sides is equal and the effective area is equal. Since the built-in main spring 402 is in a compressed state, the force provided by it resets the main valve core 401, that is, the oil port of the pilot control valve group 4 is closed;

[0064] (2) When the buoy dives into the deep cold seawater, the expanded phase-change medium begins to solidify and shrinks in volume. At this time, the pressure in the rubber bladder drops to 0 or negative pressure, which is less than the pressure in the oil tank 7, that is, the pressure on the left side of the one-way valve 8 is less than the pressure on the right side. The main valve core 401 opens, and the oil in the oil tank 7 is replenished into the cavity between the rubber bladder 12 and the accumulator 3 through the one-way valve 8 until the phase-change medium 1 is completely solidified. The volume no longer changes, the hydraulic oil no longer flows, and the buoy waits for the next buoyancy. When the phase-change medium melts, the buoy re-enters the next working cycle.

[0065] The working process of the pilot control valve group is:

[0066] When the pressure of the oil chamber 4012 in the main valve core does not reach the set pressure, the pilot valve core 404 is in a normally closed state under the action of the pilot spring 405, and the pressure of the first oil passage 1101 is equal to the pressure of the second oil passage 1102. When the main valve core 401 does not move, the axial damping hole 4011 communicates with the oil chamber 4012 and the second oil passage 1102. According to Pascal's principle, the pressures at the left and right ends of the main valve core 401 are equal, and the effective areas are equal, so the main valve core 401 does not move;

[0067] When the pressure in the oil chamber 4012 increases to overcome the spring force of the pilot spring 405, the pilot valve core 404 moves left, and the hydraulic oil flows through the oil drain port 4031 into the third oil channel 1103. At this time, the hydraulic oil in the main valve core 401 flows. According to Bernoulli's theorem, due to the effect of the small damping hole, the pressure in the oil chamber 4012 decreases, and the pressure difference between the left and right sides of the main valve core 401 increases, pushing the main valve core 401 and the main spring 402 to move left, and the annular groove 4013 moves left accordingly, connecting the first oil channel 1101 with the third oil channel 1103. At the same time, due to the leftward movement of the main valve core 401, the radial damping hole 4014 connects the oil in the oil chamber 4012 with the third oil channel 1103. The stiffness of the main spring 402 is extremely small, and it only plays a reset role. Under the action of the oil pressure, the main valve core 401 moves left to the limit position, the opening between the first oil channel 1101 and the third oil channel 1103 is the largest, and the throttling effect is the smallest.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ocean temperature difference driven buoy autonomous power generation hydraulic system, characterized in that: It includes a rubber bladder, an accumulator, a pilot control valve group, a turbine shaft assembly, a generator, a fuel tank, an upper pressure-resistant shell, a lower pressure-resistant shell and an integrated end cover, among which: The upper pressure-resistant shell and the lower pressure-resistant shell are sealed and connected by an integrated end cover. A pilot control valve group, a turbine shaft assembly and an oil tank are arranged on the upper side of the integrated end cover. The turbine shaft assembly is connected to a generator. A rubber bladder is arranged on the lower side of the integrated end cover. An accumulator is arranged in the rubber bladder. The space between the accumulator and the rubber bladder is filled with hydraulic oil. The space between the rubber bladder and the lower pressure-resistant shell is filled with a phase-change working medium. The pilot control valve group includes a main valve core, a main spring, a main valve end cover, a valve body, a pilot spring and a pilot valve core, wherein the outer wall of the valve body is arranged in the integrated end cover through a thread, the main valve end cover is fixedly arranged at one end of the valve body, a pilot spring is arranged in the valve body, one side of the pilot spring is connected to the pilot valve core, the pilot valve core contacts the inner side of the main valve end cover, the outer side of the main valve end cover is connected to the main valve core through the main spring, and an annular groove is arranged on the outer wall of the main valve core; A first oil passage connected to the accumulator is arranged in the integrated end cover at the lower side of the main valve core, a second oil passage is arranged on one side of the first oil passage, the lower side of the second oil passage is connected to the accumulator, the upper side of the second oil passage is respectively connected to the oil tank and the main valve core, a one-way valve is arranged at the connection position between the second oil passage and the oil tank, a third oil passage is arranged in the integrated end cover at the upper side of the main valve core, and the oil discharged from the third oil passage flows to the turbine shaft assembly; An oil drain port is built into the upper side of the valve body, which is connected to the inner cavity of the valve body and the third oil channel. An axial damping hole connected to the second oil channel is arranged on one side of the main valve core, and a penetrating radial damping hole is arranged on the top of the main valve core. The inside of the main valve core is an oil chamber, and the main valve end cover is connected to the oil chamber. The turbine shaft assembly is arranged in the through hole at the top of the integrated end cover. The turbine shaft assembly includes a guide cover, a turbine shaft and a valve block end cover. Blades are arranged axially and obliquely on the side wall of the turbine shaft. The lower end of the turbine shaft is connected to the guide cover through a bearing A, and the upper end of the turbine shaft is connected to the valve block end cover through a bearing B. The guide cover and the valve block end cover are arranged in the through hole. A generator is connected to the top of the turbine shaft. The upper space of the turbine shaft is connected to the oil tank through the fourth oil channel, and the space between the lower part of the turbine shaft and the guide cover is the fifth oil channel.

2. The ocean temperature difference energy driven buoy autonomous power generation hydraulic system as claimed in claim 1, characterized in that: The accumulator comprises an outer shell, an isolating piston and an air-charging end cover. The air-charging end cover is fixedly arranged at the bottom of the outer shell, the isolating piston is slidably arranged in the middle of the outer shell, and radial oil holes are arranged at the top of the outer shell.

3. The ocean temperature difference energy driven buoy autonomous power generation hydraulic system as claimed in claim 2, characterized in that: The upper part of the outer shell is provided with a step surface.

4. The ocean temperature difference energy driven buoy autonomous power generation hydraulic system as claimed in claim 3, characterized in that: An adjusting knob is arranged on one side of the valve body away from the pilot valve core. One end of the adjusting knob is threadedly connected to the valve body, and the other end is connected to the pilot spring.

5. The ocean temperature difference energy driven buoy autonomous power generation hydraulic system as claimed in claim 4, characterized in that: A threaded groove connected to the turbine shaft is arranged in the middle of the guide cover plate, and a plurality of inclined oil holes are arranged around the guide cover plate; The diameter of the circle surrounded by the blades is the same as the diameter of the through hole at the top of the integrated end cover.

6. The working method of the ocean temperature difference energy driven buoy autonomous power generation hydraulic system as claimed in claim 5, characterized in that: Here are the steps: (1) The power generation hydraulic system is installed on the buoy. When it floats to the surface warm seawater, the seawater temperature is higher than the melting temperature of the phase change medium. The phase change medium expands due to heat, and the hydraulic oil in the rubber bladder is forced to reduce in volume and flows out through the radial oil hole to the upper chamber of the accumulator, pushing the isolation piston downward, compressing the volume of nitrogen, and increasing the oil pressure at the upper end of the accumulator. Due to the one-way valve, the hydraulic oil cannot flow back into the oil tank and can only apply pressure to the pilot control valve group. When the pressure rises to the point where the pilot control valve group is fully opened, the isolation piston moves upward due to the reduction of upper pressure, pushing the hydraulic oil into the fifth oil passage after changing the incident angle through the guide cover plate, pushing the turbine shaft to rotate, driving the generator to generate electricity, and the hydraulic oil flowing through the turbine shaft enters the oil tank through the fourth oil passage, causing the pressure in the oil tank to rise; When the upper part of the isolation piston contacts the step surface inside the outer shell and stops moving, the hydraulic oil pressure on the upper part of the accumulator no longer changes, and the oil inside the main valve core no longer flows. According to Pascal's principle, the oil pressure on both sides is equal and the effective area is equal. Since the built-in main spring is in a compressed state, the force provided resets the main valve core, that is, the oil port of the pilot control valve group is closed; (2) When the buoy dives into the deep cold sea water, the expanded phase-change medium begins to solidify and shrinks in volume. At this time, the pressure in the rubber bladder drops to 0 or negative pressure, which is lower than the pressure in the oil tank. The pressure on the left side of the one-way valve is lower than the pressure on the right side. The main valve core opens, and the oil in the oil tank is replenished into the cavity between the rubber bladder and the accumulator through the one-way valve until the phase-change medium is completely solidified. The volume no longer changes, and the hydraulic oil no longer flows, waiting for the next buoyancy. When the phase-change medium melts, it re-enters the next working cycle.

7. The working method of the ocean temperature difference energy driven buoy autonomous power generation hydraulic system as claimed in claim 6, characterized in that: The working process of the pilot control valve group is: When the pressure in the oil chamber of the main valve core does not reach the set pressure, the pilot valve core is in a normally closed state under the action of the pilot spring, and the pressures of the first oil channel and the second oil channel are equal. When the main valve core does not move, the axial damping hole connects the oil chamber and the second oil channel. According to Pascal's principle, the pressures at the left and right ends of the main valve core are equal, and the effective areas are equal, so the main valve core does not move; When the pressure in the oil chamber rises to overcome the spring force of the pilot spring, the pilot valve core moves left, and the hydraulic oil flows through the oil drain port into the third oil channel. At this time, the hydraulic oil in the main valve core flows, the pressure in the oil chamber decreases, and the pressure difference between the left and right sides of the main valve core increases, pushing the main valve core and the main spring to move left, and the annular groove moves left accordingly, connecting the first oil channel with the third oil channel. At the same time, due to the leftward movement of the main valve core, the radial damping hole connects the oil in the oil chamber with the third oil channel. Under the action of oil pressure, the main valve core moves left to the extreme position, the opening between the first oil channel and the third oil channel is the largest, and the throttling effect is the smallest.

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