Hydraulic system of large-tonnage towing engine

Abstract

The invention relates to a hydraulic system of a large-tonnage towing engine. The large-tonnage towing engine hydraulic system comprises an internal combustion engine, a closed hydraulic pump, an open hydraulic pump, a hydraulic motor, a filter, a cooler, a first one-way valve and a system pipeline fitting, and the large-tonnage towing engine hydraulic system can be switched to be in one of an active cable winding working mode, an active cable unwinding working mode and a passive cable unwinding working mode. According to the large-tonnage towing engine hydraulic system, active cable collecting, active cable releasing and passive cable releasing work can be achieved, heat balance of the large-tonnage towing engine hydraulic system is guaranteed, and the system can stably work for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of marine engineering equipment manufacturing, and in particular to a large-tonnage towing winch hydraulic system. Background Art

[0002] With the implementation of deep-sea projects, marine engineering equipment also needs to develop in the direction of deep-water large-scale. Large-tonnage towing cranes are now mostly used for long-distance towing of marine platforms, deep-water anchoring and other services. They are also often used for cable collection and release during the construction of large marine platforms. They are also used for anchoring and anchoring of offshore floating wind turbines. They are important auxiliary tools for marine energy development.

[0003] Because it is located in the deep sea, with water depths ranging from hundreds to thousands of meters, the weight of the anchor chain will increase with the increase of water depth. In the process of free anchoring, the speed of the anchor chain must be guaranteed to be able to bear the weight of the anchor chain to ensure that there will be no accidents caused by unlimited acceleration due to gravity during the whole process. Large-tonnage towing winches have become the key equipment for the construction of the entire project. The offshore operating environment is harsh, the operations are frequent and intensive, and the reliability and safety requirements of the equipment are extremely high.

[0004] The main consideration of large-scale towing cranes is to achieve dynamic braking function under passive cable-releasing conditions. That is, during the cable-releasing process, it is necessary to ensure the cable-releasing speed and improve construction efficiency, while ensuring that there is sufficient impedance capacity under high-speed working conditions to achieve dynamic balance, and at the same time, it is also necessary to be able to digest the large amount of heat energy generated by the system due to passive work.

[0005] Because the system will generate a large amount of heat energy, existing technologies often use low-pressure, high-flow hydraulic systems to ensure that the heat under negative work conditions can be carried away by the large-flow hydraulic oil and digested by the heat exchanger, ensuring the thermal balance of the system and achieving stable and long-term operation of the system.

[0006] Due to the supply problem of low-pressure and high-flow components, China is often restricted by foreign manufacturers. Therefore, developing a large-tonnage towing crane hydraulic system using a high-pressure oil system is a convenient way to solve the application bottleneck. Summary of the invention

[0007] In view of the above problems in the prior art, the present invention proposes a hydraulic system for a large-tonnage towing winch, which can realize active cable collection, active cable release and passive cable release.

[0008] Specifically, the present invention proposes a large-tonnage towing machine hydraulic system, including an internal combustion engine, a closed hydraulic pump, an open hydraulic pump, a hydraulic motor, a filter, a cooler, a first non-return valve and system pipeline accessories, wherein the large-tonnage towing machine hydraulic system can be switched to one of the active cable-receiving working mode, the active cable-releasing working mode and the passive cable-releasing working mode; wherein:

[0009] In the active cable reeling working mode, the internal combustion engine drives the closed hydraulic pump to operate, and the working medium flows in the order of the closed hydraulic pump, the first one-way valve, the hydraulic motor, and then returns to the closed hydraulic pump to form a first closed loop; at the same time, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the filter, the cooler, and then returns to the open hydraulic pump to form an open loop, and the open hydraulic pump replenishes the working medium to the first closed loop;

[0010] In the active cable-releasing working mode, the internal combustion engine drives the closed hydraulic pump to operate, and the working medium flows in the order of the closed hydraulic pump, the hydraulic motor, the first one-way valve, and then returns to the closed hydraulic pump to form a second closed loop; at the same time, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the filter, the cooler, and then returns to the open hydraulic pump to form the open loop, and the open hydraulic pump replenishes the working medium to the second closed loop;

[0011] In the passive cable-releasing working mode, the passive power and active power of the system are compared. If the set conditions are met, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the hydraulic motor, the filter, the cooler, and then returns to the open hydraulic pump;

[0012] If the set conditions are not met, the working medium flows in the direction of the second closed loop, and the closed hydraulic pump inputs the received energy into the internal combustion engine; or the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the direction of the open hydraulic pump, the hydraulic motor, the filter, the cooler, and then returns to the open hydraulic pump.

[0013] According to one embodiment of the present invention, the first one-way valve is a hydraulically controlled one-way valve.

[0014] According to one embodiment of the present invention, the large-tonnage towing winch hydraulic system further comprises a first reversing valve, and the first reversing valve is used to control the flow direction of the first one-way valve so as to change the flow direction of the working medium.

[0015] According to one embodiment of the present invention, the large-tonnage towing winch hydraulic system further includes a second one-way valve, and in the active retracting working mode, the open hydraulic pump replenishes the working medium to the first closed loop through the second one-way valve.

[0016] According to one embodiment of the present invention, the large-tonnage towing machine hydraulic system further includes a third one-way valve, and in the active cable-releasing working mode, the open hydraulic pump replenishes the working medium to the second closed loop through the third one-way valve.

[0017] According to one embodiment of the present invention, the large-tonnage towing winch hydraulic system further includes a first overflow valve;

[0018] In the active cable-reeling working mode and the active cable-releasing working mode, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the first overflow valve, the filter, the cooler, and then returns to the open hydraulic pump to form the open loop.

[0019] According to one embodiment of the present invention, the large-tonnage towing winch hydraulic system further includes a second reversing valve for controlling the action of the first overflow valve.

[0020] According to one embodiment of the present invention, the large-tonnage towing winch hydraulic system further includes a second overflow valve;

[0021] In the passive cable-releasing working mode, the passive power and active power of the system are compared. If the set conditions are met, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the hydraulic motor, the second overflow valve, the filter, the cooler, and then returns to the open hydraulic pump.

[0022] According to one embodiment of the present invention, the second relief valve is a safety relief valve or a proportional relief valve.

[0023] According to one embodiment of the present invention, the large-tonnage towing winch hydraulic system further includes an accumulator connected to an oil suction line of the open hydraulic pump.

[0024] The invention provides a large-tonnage towing machine hydraulic system, which can effectively switch between active cable-collecting working mode, active cable-releasing working mode and passive cable-releasing working mode, thereby ensuring the thermal balance of the large-tonnage towing machine hydraulic system and achieving stable and long-term operation of the system.

[0025] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and together with the description serve to explain the principle of the present invention.

[0027] In the attached figure:

[0028] Figure 1 The schematic diagram of the structure of the hydraulic system of a large-tonnage towing winch according to one embodiment of the present invention is shown.

[0029] The above drawings include the following reference numerals:

[0030] Large tonnage towing winch hydraulic system 100

[0031] Internal Combustion Engine 101

[0032] Closed hydraulic pump 102

[0033] Open hydraulic pump 103

[0034] Hydraulic motor 104

[0035] Filter 105

[0036] Cooler 106

[0037] First check valve 107

[0038] The first reversing valve 108

[0039] The second one-way valve 109

[0040] The third one-way valve 110

[0041] The first relief valve 111

[0042] The second reversing valve 112

[0043] Second relief valve 113

[0044] Accumulator 114 DETAILED DESCRIPTION

[0045] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0047] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0048] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0049] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0050] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0051] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0052] Figure 1 The structural schematic diagram of the hydraulic system of a large-tonnage towing winch according to an embodiment of the present invention is shown. As shown in the figure, a large-tonnage towing winch hydraulic system 100 mainly includes an internal combustion engine 101, a closed hydraulic pump 102, an open hydraulic pump 103, a hydraulic motor 104, a filter 105, a cooler 106, a first non-return valve 107 and system pipeline accessories. The large-tonnage towing winch hydraulic system 100 can be switched in one of the working modes of active cable-receiving working mode, active cable-releasing working mode and passive cable-releasing working mode.

[0053] The internal combustion engine 101 is used to drive a series pump group consisting of a closed hydraulic pump 102 and an open hydraulic pump 103. The closed hydraulic pump 102, the first one-way valve 107, and the hydraulic motor 104 form a closed system. The closed system performs positive or negative work, provides the power for cable winding speed and overcoming the gravity of the cable, and consumes the anchor cable gravity work through dynamic braking to increase the cable release speed and load; the open hydraulic pump 103, the filter 105, and the cooler 106 form an open system. The open system performs negative work, consumes the anchor cable gravity work through dynamic braking to increase the cable release speed and load, thereby realizing controllable active cable winding and passive cable release through this combined application. It should be noted that, as an example and not a limitation, the internal combustion engine 101 can be replaced by an electric motor to drive the closed hydraulic pump 102 and the open hydraulic pump 103.

[0054] in, It is used to indicate the circulation direction of the working medium. In the active cable-reeling working mode, the hydraulic motor 104 performs work and outputs kinetic energy to the cable drum to perform cable-reeling. It is used to indicate the circulation direction of the working medium. In the active cable-releasing working mode, the hydraulic motor 104 performs work and outputs kinetic energy to the cable drum to release the cable. In the passive cable-releasing working mode, the cable drum inputs kinetic energy to the hydraulic motor 104 to release the cable passively. ← It is used to indicate the circulation direction of the working medium. In the passive cable-releasing working mode, the cable drum inputs kinetic energy to the hydraulic motor 104 to release the cable passively.

[0055] Specifically, in the active cable reeling working mode, the internal combustion engine 101 drives the closed hydraulic pump 102 to operate, and the working medium flows in the direction of the closed hydraulic pump 102, the first one-way valve 107, the hydraulic motor 104, and then returns to the closed hydraulic pump 102, as indicated by the arrow, to form a first closed loop. In other words, the closed hydraulic pump 102 pumps the working medium (for example, hydraulic oil) into the hydraulic motor 104 through the first one-way valve 107, and the pressure difference between the inlet and outlet of the hydraulic motor 104 drives the cable drum to work, completing the reeling work. The working medium returns to the closed hydraulic pump 102 through the hydraulic motor 104. At the same time, the internal combustion engine 101 drives the open hydraulic pump 103 to operate, and the working medium flows in the direction of the open hydraulic pump 103, the filter 105, the cooler 106, and then returns to the open hydraulic pump 103, forming an open loop. Because the hydraulic motor 104 and the closed hydraulic pump 102 have internal leakage that causes the loss of working medium, in order to prevent the closed hydraulic pump 102 from sucking air due to insufficient working medium, the open hydraulic pump 103 replenishes the working medium to the first closed loop. In the active cable reeling working mode, the hydraulic motor 104 works to output kinetic energy to the cable drum to perform cable reeling.

[0056] In the active cable-releasing working mode, the internal combustion engine 101 drives the closed hydraulic pump 102 to operate, and the working medium flows in the order of the closed hydraulic pump 102, the hydraulic motor 104, the first one-way valve 107, and then returns to the closed hydraulic pump 102, forming a second closed loop. Obviously, the working medium in the first closed loop and the second closed loop has opposite flow directions. At the same time, the internal combustion engine 101 drives the open hydraulic pump 103 to operate, and the working medium flows in the order of the open hydraulic pump 103, the filter 105, the cooler 106, and then returns to the open hydraulic pump 103, forming an open loop, as in the active collection working mode. The open hydraulic pump 103 replenishes the working medium to the second closed loop. In the active cable-releasing working mode, the hydraulic motor 104 performs work to output kinetic energy to the cable drum to execute cable-releasing.

[0057] In the passive cable-releasing working mode, the main power source of the towing winch system is the energy input of the external anchor chain to the cable drum. The main function of the towing winch hydraulic system is converted into auxiliary power for the hydraulic motor 104 to realize the dynamic braking function. At the same time, the passive input kinetic energy is converted into heat and exchanged out through the cooler 106 in the towing winch hydraulic system. Specifically, the passive power and active power of the system are compared. If the set conditions are met, the internal combustion engine 101 drives the open hydraulic pump 103 to operate, and the working medium flows in the order of the open hydraulic pump 103, the hydraulic motor 104, the filter 105, the cooler 106, and then returns to the open hydraulic pump 103. In other words, the open hydraulic pump 103 pumps the working medium to the hydraulic motor 104. Under the energy input of the cable drum, the hydraulic motor 104 increases the pressure of the working medium, which is equivalent to converting the received external kinetic energy into the heat energy of the working medium and entering the hydraulic system. After filtering by the filter 105 and cooling by the cooler 106, it returns to the open hydraulic pump 103 to complete the system cycle. The hydraulic motor 104 provides auxiliary power to realize the dynamic braking function. It should be noted that, in this case, the working medium can also flow in the second closed loop at the same time, which is equivalent to combining the open system with the closed system to consume the passive power input.

[0058] If the set conditions are not met, the working medium flows in the direction of the second closed loop, that is, the working medium flows in the direction of the closed hydraulic pump 102, the hydraulic motor 104, the first one-way valve 107, and then returns to the closed hydraulic pump 102. The closed hydraulic pump 102 inputs the received energy to the internal combustion engine 101 through the coupling. Or the internal combustion engine 101 drives the open hydraulic pump 103 to operate, and the working medium flows in the direction of the open hydraulic pump 103, the hydraulic motor 104, the filter 105, the cooler 106, and then returns to the open hydraulic pump 103. In other words, if the set conditions are not met, either the closed system or the open system can be selected to consume the passive power input.

[0059] Among them, the closed hydraulic pump 102 inputs the received energy to the internal combustion engine 101 through the coupling. Specifically, the rotation torque generated by the pressure difference between the two oil ports of the closed hydraulic pump 102 is in the same direction as the torque of the internal combustion engine 101, which is equivalent to rotating the internal combustion engine 101, so that the received energy can be transmitted. Under normal circumstances, the rotation torque generated by the pressure difference between the two oil ports of the closed hydraulic pump 102 is opposite to the torque of the internal combustion engine 101, and the internal combustion engine 101 is resisted from rotating.

[0060] As an example and not a limitation, the set condition may be that the passive power of the system is greater than 120% of the active power. Specifically, the passive power of the system is compared with the active power. If the passive power is greater than 120% of the active power, an open system is preferred, or an open system is selected in combination with a closed system to consume the passive power input. If the passive power is not greater than 120% of the active power, a closed system or an open system is selected to consume the passive power input. It is easy to understand that the set condition may also be that the passive power of the system is greater than 125% or 130% of the active power, which is set according to the actual working conditions.

[0061] When the large-tonnage towing winch hydraulic system 100 is in operation, the filter 105 is always in operation to clean the working medium and ensure the stability of the system operation.

[0062] In some examples, the first one-way valve 107 is a hydraulically controlled one-way valve, which is easy to achieve reverse conduction of the working medium.

[0063] In some examples, the large-tonnage towing winch hydraulic system 100 further includes a first reversing valve 108. The first reversing valve 108 is used to control the flow direction of the first check valve 107 so that the working medium changes its flow direction. The first reversing valve 108 may be a solenoid valve. When the first reversing valve 108 is energized to control the first check valve 107 to open in reverse, the working medium circulates in accordance with the second closed loop.

[0064] In some examples, the large-tonnage towing machine hydraulic system 100 further includes a second one-way valve 109. The second one-way valve 109 is connected between the closed system and the open system. In the active collection working mode, as shown in the figure, the open hydraulic pump 103 pumps the working medium to supplement the first closed loop through the second one-way valve 109 and merges into the hydraulic motor 104. In the passive cable release working mode, if the passive power is greater than 120% of the active power, the working medium flows from the open hydraulic pump 103 to the hydraulic motor 104 through the second one-way valve 109.

[0065] In some examples, the large-tonnage towing machine hydraulic system 100 further includes a third one-way valve 110. The third one-way valve 110 is connected between the closed system and the open system. In the active cable-releasing working mode, as shown in the figure, the open hydraulic pump 103 pumps the working medium to replenish the second closed loop through the third one-way valve 110 and merges into the closed hydraulic pump 102.

[0066] In some examples, the large-tonnage towing machine hydraulic system 100 further includes a first relief valve 111, which is connected in series between the open hydraulic pump 103 and the filter 105. In the active cable-collecting working mode and the active cable-releasing working mode, the internal combustion engine 101 drives the open hydraulic pump 103 to operate, and the working medium flows in the order of the open hydraulic pump 103, the first relief valve 111, the filter 105, the cooler 106, and then returns to the open hydraulic pump 103, forming an open loop.

[0067] In some examples, the large-tonnage towing machine hydraulic system 100 further includes a second reversing valve 112 for controlling the action of the first relief valve 111. The second reversing valve 112 may be a solenoid valve. In the active cable-reeling working mode and the active cable-releasing working mode, the second reversing valve 112 is energized to control the action of the first relief valve 111, and the working medium enters the filter 105 via the first relief valve 111.

[0068] In some examples, the large-tonnage towing machine hydraulic system 100 further includes a second relief valve 113, which is connected in series between the hydraulic motor 104 and the filter 105. In the passive cable-releasing working mode, if the set conditions are met (the passive power is greater than 120% of the active power), the internal combustion engine 101 drives the open hydraulic pump 103 to operate, and the working medium flows in the order of the open hydraulic pump 103, the hydraulic motor 104, the second relief valve 113, the filter 105, the cooler 106, and then returns to the open hydraulic pump 103. At this time, the first reversing valve 108 is not electrically operated, the first solenoid valve is turned off, and the energy received by the hydraulic motor 104 is consumed by the heat exchange method of the cooler 106. The closed hydraulic pump 102 is in a zero-displacement working state. If the passive cable-releasing speed is further increased, the first reversing valve 108 is energized and operated, the first solenoid valve is turned on, and the pressure working medium pumped by the hydraulic motor 104 flows back to the closed hydraulic pump 102 via the first one-way valve 107. The closed hydraulic pump 102 is in a full-displacement working state, and part of the passively input kinetic energy is fed back to the internal combustion engine 101 by the closed hydraulic pump 102, and further fed back to the onboard power grid, or driven to consume the flywheel of the internal combustion engine 101.

[0069] In some examples, the second relief valve 113 is a safety relief valve or a proportional relief valve.

[0070] In some examples, the large-tonnage towing machine hydraulic system 100 further includes an accumulator 114, which is connected to the oil suction pipeline of the open hydraulic pump 103. The accumulator 114 can improve the oil suction performance. During the oil suction process of the open hydraulic pump 103, when there is pressure fluctuation in its oil suction pipeline or the hydraulic pump runs at a high speed, resulting in untimely oil suction, the accumulator 114 can release the stored oil to supplement the oil suction, thereby maintaining the oil suction pipeline pressure of the open hydraulic pump 103, and ensuring that the open hydraulic pump 103 can stably suck oil during the entire working process.

[0071] In some examples, the open hydraulic pump 103 can be configured to increase or decrease displacement individually based on the passive cable payout speed requirements of a specific device.

[0072] The present invention provides a large-tonnage towing machine hydraulic system, including a closed system and an open system. The closed system is used for active cable retraction and release under normal working conditions, and the open system can be used for anchoring conditions or anchoring conditions. The closed system performs positive work to provide cable retraction speed and power to overcome the gravity of the cable; the open system performs negative work to consume the increase in cable release speed and load caused by the gravity work of the anchor cable through dynamic braking, so that through this combined application, controllable active cable retraction and passive cable release and anchoring can be achieved. Among them, the passive power input capacity that can be consumed by the combination of the open system and the closed system can reach 3 to 4 times the active output power of the closed system. In addition, the system is designed in a way that the pipeline stores the working medium. By increasing the diameter of the system pipeline, the working medium used by the system is stored in the pipeline system, which can save the oil storage tank and avoid the contact of the working medium with the external environment, which can further improve the cleanliness of the working medium.

[0073] It will be apparent to those skilled in the art that various modifications and variations may be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention covers modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A large-tonnage towing winch hydraulic system, characterized in that: The large-tonnage towing machine hydraulic system comprises an internal combustion engine, a closed hydraulic pump, an open hydraulic pump, a hydraulic motor, a filter, a cooler, a first non-return valve and system pipeline accessories. The large-tonnage towing machine hydraulic system can be switched to one of the active cable-receiving working mode, the active cable-releasing working mode and the passive cable-releasing working mode; wherein: In the active cable reeling working mode, the internal combustion engine drives the closed hydraulic pump to operate, and the working medium flows in the order of the closed hydraulic pump, the first one-way valve, the hydraulic motor, and then returns to the closed hydraulic pump to form a first closed loop; at the same time, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the filter, the cooler, and then returns to the open hydraulic pump to form an open loop, and the open hydraulic pump replenishes the working medium to the first closed loop; In the active cable-releasing working mode, the internal combustion engine drives the closed hydraulic pump to operate, and the working medium flows in the order of the closed hydraulic pump, the hydraulic motor, the first one-way valve, and then returns to the closed hydraulic pump to form a second closed loop; at the same time, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the filter, the cooler, and then returns to the open hydraulic pump to form the open loop, and the open hydraulic pump replenishes the working medium to the second closed loop; In the passive cable-releasing working mode, the passive power and active power of the system are compared. If the set conditions are met, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the hydraulic motor, the filter, the cooler, and then returns to the open hydraulic pump; If the set conditions are not met, the working medium flows in the direction of the second closed loop, and the closed hydraulic pump inputs the received energy into the internal combustion engine; or the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the direction of the open hydraulic pump, the hydraulic motor, the filter, the cooler, and then returns to the open hydraulic pump.

2. The large-tonnage towing winch hydraulic system according to claim 1, characterized in that: The first one-way valve is a hydraulically controlled one-way valve.

3. The large-tonnage towing winch hydraulic system according to claim 2, characterized in that: The large-tonnage towing winch hydraulic system further includes a first reversing valve, which is used to control the flow direction of the first one-way valve so as to change the flow direction of the working medium.

4. The large-tonnage towing winch hydraulic system according to claim 1, characterized in that: The large-tonnage towing winch hydraulic system further includes a second one-way valve. In an active retracting working mode, the open hydraulic pump replenishes the working medium to the first closed loop through the second one-way valve.

5. The large-tonnage towing winch hydraulic system according to claim 1, characterized in that: The large-tonnage towing machine hydraulic system further includes a third one-way valve. In the active cable-releasing working mode, the open hydraulic pump replenishes the working medium to the second closed loop through the third one-way valve.

6. The large-tonnage towing winch hydraulic system according to claim 1, characterized in that: The large-tonnage towing winch hydraulic system also includes a first overflow valve; In the active cable-reeling working mode and the active cable-releasing working mode, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the first overflow valve, the filter, the cooler, and then returns to the open hydraulic pump to form the open loop.

7. The large-tonnage towing winch hydraulic system according to claim 6, characterized in that: The large-tonnage towing winch hydraulic system further comprises a second reversing valve for controlling the action of the first overflow valve.

8. The large-tonnage towing winch hydraulic system according to claim 1, characterized in that: The large-tonnage towing winch hydraulic system also includes a second overflow valve; In the passive cable-releasing working mode, the passive power and active power of the system are compared. If the set conditions are met, the internal combustion engine drives the open hydraulic pump to operate, and the working medium flows in the order of the open hydraulic pump, the hydraulic motor, the second overflow valve, the filter, the cooler, and then returns to the open hydraulic pump.

9. The large-tonnage towing winch hydraulic system according to claim 8, characterized in that: The second relief valve is a safety relief valve or a proportional relief valve.

10. The large-tonnage towing winch hydraulic system according to claim 1, characterized in that: The large-tonnage towing winch hydraulic system also includes an accumulator connected to the oil suction pipeline of the open hydraulic pump.

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