Hydraulic driving system, active combined back pressure real-time adjusting module and control method

Abstract

The invention discloses a hydraulic driving system and an active combined back pressure real-time adjusting module and a control method thereof. The active combined backpressure implementation adjustment module comprises an oil return pipe, an oil pressure supplement pipe, a first one-way valve, a second one-way valve, a proportional valve, a pressure sensor and a controller. The first one-way valve and the proportional valve are sequentially arranged in the oil conveying direction of the oil return pipe and communicate with each other through a middle pipe section of the oil return pipe. The oil pressure supplementing pipe communicates with the middle pipe section. The pressure sensor senses the oil pressure of the middle pipe section in real time, and the controller controls the proportional valve according to an oil pressure signal fed back by the pressure sensor in real time, so that the back pressure of the middle pipe section is effectively and accurately adjusted in real time.

Description

Technical Field

[0001] This invention relates to the field of marine hydraulic drive system technology, and in particular to a hydraulic drive system and its active combined real-time back pressure adjustment module and control method. Background Technology

[0002] Marine hydraulic systems are generally used in hydraulic actuators that drive the ship, such as steering mechanisms and control propellers operating underwater. For underwater hydraulic actuators, due to water pressure, external water can easily seep into the return oil pipe and oil tank through the joints in the hydraulic system's return oil line. Therefore, a back pressure device is needed to provide back pressure to the return oil pipe. Currently, most back pressure devices can maintain the back pressure value within a certain fixed range. However, when the back pressure value changes due to oil temperature variations, oil pipe leaks, or changes in the ship's draft requiring adjustment, existing back pressure devices cannot effectively, accurately, and in real-time adjust the back pressure.

[0003] Therefore, how to provide a technical solution that can effectively, accurately, and in real time adjust back pressure has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a hydraulic drive system and its active combined real-time back pressure adjustment module and control method, which can effectively, accurately and in real time adjust the pipeline back pressure.

[0005] This invention is achieved using the following technical solution: An active combined back pressure real-time adjustment module is applied to a marine hydraulic drive system. The active combined back pressure real-time adjustment module includes a return oil pipe, an oil pressure replenishment pipe, a first check valve, a second check valve, a proportional valve, a pressure sensor, and a controller. The first check valve and the proportional valve are sequentially arranged in the return oil pipe along the return oil direction, allowing hydraulic oil in the return oil pipe to flow sequentially through the first check valve and the proportional valve. The return oil pipe includes an intermediate section, through which the outlet of the first check valve and the inlet of the proportional valve are connected. The outlet of the oil pressure replenishment pipe is connected to the intermediate section. The second check valve is located in the oil pressure replenishment pipe to limit the unidirectional delivery of pressurized oil. The pressure sensor is configured to sense the oil pressure in the intermediate section in real time, and feeds back a pressure signal to the controller so that the controller controls the proportional valve.

[0006] In an optional embodiment, the active combined back pressure real-time adjustment module further includes an accumulator and a one-way throttle valve; the oil pressure replenishment pipe includes an output pipe section, one end of which is connected to the oil outlet of the second one-way valve, and the other end is connected to the intermediate pipe section; the accumulator is connected to the output pipe section through the one-way throttle valve. When the oil pressure replenishment pipe delivers pressure oil to the intermediate pipe section, a portion of the pressure oil in the output pipe section flows into the accumulator through the one-way throttle valve. When the oil pressure delivery pipe stops delivering pressure oil to the intermediate pipe section, the pressure oil in the accumulator delivers pressure oil to the output pipe section through the one-way throttle valve.

[0007] In one optional embodiment, the active combined back pressure real-time adjustment module further includes an electromagnetic reversing valve, which is located on the oil pressure replenishment pipe to control the opening and closing of the oil pressure replenishment pipe; the electromagnetic reversing valve and the second check valve are arranged sequentially along the direction of conveying pressurized oil in the oil pressure replenishment pipe; the electromagnetic reversing valve is electrically connected to the controller, and the controller controls the opening and closing of the electromagnetic reversing valve.

[0008] In one optional embodiment, the active combined back pressure real-time adjustment module further includes a two-position two-way hydraulic directional valve, which is connected to the return oil pipe and is arranged in parallel with the first check valve.

[0009] In an optional embodiment, the active combined back pressure real-time adjustment module further includes a protection valve group, which is connected to the return oil pipe and is arranged in parallel with the proportional valve.

[0010] In one alternative embodiment, the protection valve assembly includes a first safety valve connected to the return oil pipe.

[0011] In one optional embodiment, the protective valve further includes a two-position three-way solenoid valve and a second safety valve; the oil inlet of the two-position three-way solenoid valve is connected to the return oil pipe, and the two oil outlets of the two-position three-way solenoid valve are respectively connected to the oil inlet of the first safety valve and the oil inlet of the second safety valve; the two-position three-way solenoid valve is electrically connected to the controller, and the controller controls the opening and closing of the two oil outlets of the two-position three-way solenoid valve; the oil outlet of the first safety valve is connected to the return oil pipe; the oil outlet of the second safety valve is connected to the return oil pipe and is arranged in parallel with the first safety valve; the threshold of the second safety valve is higher than the threshold of the first safety valve.

[0012] In one alternative embodiment, both the first safety valve and the second safety valve are relief valves.

[0013] In some embodiments of this application, a hydraulic drive system is also provided, which includes at least an oil tank, a working oil pump, a pressure oil source, an actuator, and the aforementioned active combined back pressure real-time adjustment module; the oil tank, the working oil pump, and the actuator are connected in sequence through pipelines to form a hydraulic circuit; the return port of the hydraulic circuit is connected to the oil tank through a return oil pipe; the pressure oil source is connected to the inlet of the oil pressure replenishment pipe.

[0014] In some embodiments of this application, a ship is also provided, including the aforementioned hydraulic drive system.

[0015] In some embodiments of this application, a control method for a hydraulic drive system is also provided. The control method is applied to the hydraulic drive system described in any of the above embodiments. The control method includes: adaptively controlling the return oil pipe pressure by controlling a proportional valve, so that the return oil pipe pressure is greater than the pressure of the external environment.

[0016] Compared to existing technologies, the beneficial effects of this invention are at least as follows: In some embodiments of this invention, the oil pressure replenishment pipe connects to the intermediate section of the return oil pipe, the intermediate section connects to a first check valve and a proportional valve, and a second check valve is installed on the oil pressure replenishment pipe. The first check valve, the second check valve, and the proportional valve enable the intermediate section to maintain an adaptive and stable back pressure. The proportional control of the proportional valve achieves adaptive pressure control, ensuring that the pressure changes in coordination with changes in external pressure. By connecting the oil source to a two-position, two-way solenoid directional valve and combining this with the fast charging and slow discharging characteristics of the accumulator, even if there is no return oil in the main return oil pipe or internal and external leaks in the pipeline, a certain pressure can be maintained in the intermediate section for a long time, thus enabling active control of the return oil pipe to maintain the required pressure.

[0017] In some embodiments, two safety valves with different set pressures are provided, enabling multi-stage safety protection for the return oil pipe when the proportional relief valve becomes stuck. In some embodiments, a two-position, two-way hydraulic directional valve is connected in parallel with the first check valve. When the first check valve malfunctions and becomes stuck, or when the pressure before and after the first check valve exceeds a set value, the first check valve is bypassed. In the embodiments of this application, the above design achieves safety protection for the return oil back pressure when any component in the main circuit becomes stuck, improving the reliability of the return oil back pressure under fault conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing the connection relationship of the active combined back pressure real-time adjustment module in some embodiments of this application.

[0019] Figure 2 Schematic diagrams of hydraulic drive systems according to some embodiments of this application.

[0020] The diagram is labeled as follows: 10. Return oil pipe; 11. Intermediate pipe section; 20. First check valve; 30. Proportional valve; 40. Oil pressure replenishment pipe; 41. Output pipe section; 42. Second check valve; 43. Solenoid directional valve; 51. Accumulator; 52. One-way throttle valve; 60. Pressure sensor; 70. Two-position two-way hydraulic directional valve; 80. Protection valve assembly; 81. First safety valve; 82. Second safety valve; 83. Two-position three-way solenoid valve; 91. Oil tank; 92. Pressure oil source. Detailed Implementation

[0021] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0022] This embodiment discloses an active combined back pressure real-time adjustment module for effectively, accurately, and in real-time adjusting the back pressure of a pipeline. In some embodiments, it is applied to a hydraulic drive system. In some embodiments, the hydraulic drive system is a marine hydraulic drive system. In some embodiments, the active combined back pressure real-time adjustment module is applied to a marine hydraulic drive system.

[0023] Please combine Figure 1 and Figure 2 The active combined back pressure real-time adjustment module includes a return oil pipe 10, an oil pressure replenishment pipe 40, a first check valve 20, a second check valve 42, a proportional valve 30, a pressure sensor 60, and a controller. These components can be integrated onto a support carrier, such as a support frame, support plate, or housing, to form an integrated block that can be disassembled and installed as a whole in the hydraulic drive system, facilitating replacement and maintenance. The first check valve 20 and the proportional valve 30 are sequentially arranged along the return oil pipe 10 in the return oil direction, allowing hydraulic oil in the return oil pipe 10 to flow sequentially through them. The return oil pipe 10 includes an intermediate pipe section 11, through which the outlet of the first check valve 20 and the inlet of the proportional valve 30 are connected. The outlet of the oil pressure replenishment pipe 40 is connected to the intermediate pipe section 11. The second check valve 42 is located in the oil pressure replenishment pipe 40 to limit the one-way delivery of pressurized oil in the oil pressure replenishment pipe 40. The pressure sensor 60 is configured to sense the oil pressure in the intermediate pipe section 11 in real time, and to feed back a pressure signal to the controller so that the controller controls the proportional valve 30 to change the flow rate.

[0024] This embodiment employs a first check valve 20, a second check valve 42, an oil pressure replenishment pipe 40, and a proportional valve 30 to maintain a stable back pressure in the intermediate pipe section 11. The principle is as follows: when oil from the return pipe 10 flows into and out of the first check valve 20 from its inlet, the valve core structure of the first check valve 20 prevents it from flowing back to its inlet. The oil flowing out of the first check valve 20 can only continue flowing through the intermediate pipe section 11 towards the proportional valve 30. Similarly, when pressurized oil supplied by the oil pressure replenishment pipe 40 flows into and out of the second check valve 42 from its inlet, the pressurized oil cannot flow back to its inlet and can only flow towards the intermediate pipe section 11. The proportional control of the proportional valve 30 enables adaptive control of the pressure at its inlet, ensuring its pressure changes in harmony with external pressure variations. In this embodiment, the proportional valve 30 is a proportional relief valve. In this embodiment, hydraulic oil from the return pipe reaches the inlet of the proportional relief valve via a first check valve. A pressure sensor provides real-time pressure feedback, which is compared to a set value. When the inlet pressure is lower than the set value, the proportional relief valve is closed, and an external oil source supplies oil through a pressure supplement pipe. When the inlet pressure exceeds the set value, the proportional relief valve, under the influence of a control signal, brings the inlet pressure within the required range. In this embodiment, an active combined back pressure real-time adjustment module provides return back pressure to the return pipe, ensuring its pressure exceeds the external ambient pressure. Adaptive control of the return pipe pressure is achieved by controlling the proportional valve. In some embodiments, the hydraulic drive system is a marine hydraulic drive system, where the inlet pressure setpoint matches the ship's outboard water pressure.

[0025] In some embodiments, the active combined back pressure real-time adjustment module further includes an accumulator 51 and a one-way throttle valve 52. The oil pressure replenishment pipe 40 includes an output pipe section 41, one end of which is connected to the oil outlet of the second one-way valve 42, and the other end is connected to the intermediate pipe section 11. The accumulator 51 is connected to the output pipe section 41 via the one-way throttle valve 52.

[0026] Under normal circumstances, the flow rate of the proportional valve 30 can be changed by controlling the opening degree of the proportional valve 30 through the controller, which can effectively, accurately, and in real time adjust the oil pressure in the intermediate pipe section 11 within a certain range. However, when a leak occurs in the pipeline, a valve malfunctions, or other related components malfunction, causing the oil pressure in the intermediate pipe section 11 to fall below the preset minimum oil pressure value, pressurized oil can be introduced into the intermediate pipe section 11 through the oil pressure supplement pipe 40 to increase the oil pressure in the intermediate pipe section 11.

[0027] Specifically, the process of supplying pressurized oil from the hydraulic replenishment pipe 40 to the intermediate pipe section 11 includes: during the process of supplying pressurized oil from an external pressurized oil source to the intermediate pipe section 11 through the hydraulic replenishment pipe 40, when the pressurized oil flows through the output pipe section 41 of the hydraulic replenishment pipe 40, part of the pressurized oil flows through the one-way throttle valve 52 into the accumulator 51 and is stored in the accumulator 51. As the amount of stored oil increases, the oil pressure in the accumulator 51 also increases. The accumulator 51 is a commonly used component in the field of hydraulic system technology; therefore, its specific structure and working principle will not be further elaborated here.

[0028] When the hydraulic delivery pipe stops supplying pressurized oil to the intermediate pipe section 11, the pressurized oil in the accumulator 51 is slowly supplied to the output pipe section 41 through the one-way throttle valve 52 for a certain period of time, so that the oil pressure in the intermediate pipe section 11 can be maintained within a reasonable range. The one-way throttle valve 52 is a commonly used component in the field of hydraulic system technology, therefore its specific structure and working principle will not be further described here.

[0029] In some embodiments, the active combined back pressure real-time adjustment module further includes an electromagnetic directional valve 43, which is located in the oil pressure replenishment pipe 40 to control the opening and closing of the oil pressure replenishment pipe 40. The electromagnetic directional valve 43 and the second one-way valve 42 are sequentially arranged along the direction of pressurized oil delivery in the oil pressure replenishment pipe 40. The electromagnetic directional valve 43 is electrically connected to the controller. When the pressure sensor 60 senses that the oil pressure in the intermediate pipe section 11 is lower than a set value, the controller controls the electromagnetic directional valve 43 to open based on the oil pressure signal fed back by the pressure sensor 60, so that the pressurized oil in the pressure oil source 92 automatically flows into the oil pressure replenishment pipe 40. Specifically, in some embodiments, the electromagnetic directional valve 43 is a two-position, two-way electromagnetic directional valve. The one-way throttle valve includes a one-way valve that flows from the pressure oil source 92 to the accumulator 51. In the embodiments of this application, the pressure oil source 92 can quickly charge the accumulator through the one-way throttle valve. When the oil pressure in the intermediate pipe section 11 reaches the set value, the controller controls the solenoid directional valve to close, at which point the accumulator supplies oil to the intermediate pipe section 11 to maintain pressure. In the embodiments of this application, the one-way throttle valve includes a throttle damping valve in the direction from the accumulator 51 to the intermediate pipe section 11. By adjusting the throttle damping valve, oil is slowly supplied to the intermediate pipe section 11, increasing the pressure holding time of the intermediate pipe section 11.

[0030] In some embodiments, the active combined back pressure real-time adjustment module further includes a two-position two-way hydraulic directional valve 70, which is connected to the return oil pipe 10 and is arranged in parallel with the first check valve 20. When the first check valve 20 becomes stuck, resulting in a large resistance to the oil in the return oil pipe 10, the pressure difference between the two chambers of the first check valve increases. Under the action of hydraulic force, the two-position two-way hydraulic directional valve 70 is in the connected position, causing the two-position two-way hydraulic directional valve 70 to be open. Oil can flow through the two-position two-way hydraulic directional valve 70 and return to the middle section 11 of the return oil pipe 10. In the embodiments of this application, the first check valve 20 is bypassed, ensuring the normal use of the return oil pipe back pressure function in the event of a fault.

[0031] In some embodiments, the active combined back pressure real-time adjustment module further includes a protection valve group 80, which is connected to the return oil pipe 10 and is arranged in parallel with the proportional valve 30. When the oil pressure of the intermediate pipe section 11 is greater than the pressure threshold, the hydraulic oil of the intermediate pipe section 11 flows back to the oil tank through the protection valve group 80, and the proportional valve 30 is bypassed, thus protecting the pipeline system.

[0032] In some embodiments, the protection valve assembly 80 includes a first safety valve 81, the inlet and outlet of which are connected to the return oil pipe 10 via a pipeline, and the first safety valve 81 is arranged in parallel with the proportional valve 30. The first safety valve 81 may be a relief valve.

[0033] In some embodiments, the protective valve further includes a two-position three-way solenoid valve 83 and a second safety valve 82. The inlet of the two-position three-way solenoid valve 83 is connected to the return oil pipe 10 via a pipeline, and the two outlets of the two-position three-way solenoid valve 83 are respectively connected to the inlet of the first safety valve 81 and the inlet of the second safety valve 82 via pipelines. The outlet of the first safety valve 81 is connected to the return oil pipe 10 via a pipeline. The outlet of the second safety valve 82 is connected to the return oil pipe 10 and is configured in parallel with the first safety valve 81. The pressure threshold of the second safety valve 82 is higher than the pressure threshold of the first safety valve 81. The two-position three-way solenoid valve 83 is electrically connected to a controller, which controls the opening and closing of the two outlets of the two-position three-way solenoid valve 83.

[0034] In the embodiments of this application, the two-position three-way solenoid valve 83 is a two-position three-way solenoid directional valve. The first safety valve 81 and the second safety valve 82 are connected in parallel with the proportional valve 30. The pressure threshold of the second safety valve 82 is higher than the pressure threshold of the first safety valve 81. Specifically, the two safety valves have different set pressures. The pressure threshold of the first safety valve is a first pressure threshold, corresponding to the water pressure at the first depth (usually used depth). The pressure threshold of the second safety valve is a second pressure threshold, corresponding to the higher pressure at the second depth. At the usual depth, the two-position three-way solenoid directional valve is in its initial state. When the pressure in the intermediate pipe section 11 exceeds the first pressure threshold, the first safety valve opens to protect the pipeline system. At the higher second depth, the two-position three-way solenoid directional valve is energized and in the left position, the second safety valve operates, and provides safety protection for the pipeline, thereby achieving safety protection at different water depths.

[0035] Specifically, when the underwater depth of the ship increases, leading to an increase in external water pressure, the controller controls the opening of the oil outlet of the two-position three-way solenoid valve 83 connected to the second safety valve 82, and controls the closing of the oil outlet of the two-position three-way solenoid valve 83 connected to the first safety valve 81, thereby using the second safety valve 82, which has a higher pressure threshold, to protect the pipeline. Because the second safety valve 82 has a higher pressure threshold, the intermediate pipe section 11 requires higher oil pressure to conduct the second safety valve 82 and bypass the proportional valve 30. This means the corresponding back pressure of the intermediate pipe section 11 will also increase, matching the back pressure provided by the intermediate pipe section 11 with the high water pressure of the external environment. In the embodiments of this application, the controller receives the pressure signal (real-time pressure value) of the oil pressure in the intermediate pipe section 11 from the pressure sensor 60 in real time. The controller can also receive the external environmental pressure (water pressure value) from the water pressure sensor on the ship's hull or in the ship's hydraulic system in real time, and matches the pressure setpoint of the proportional valve according to the water pressure value. The oil pressure signal, i.e., the real-time pressure value, is compared with the set value to achieve adaptive control, so that its pressure changes in coordination with changes in external pressure.

[0036] When the ship's draft decreases, causing a drop in external water pressure, the controller opens the oil outlet of the two-position three-way solenoid valve 83 connected to the first safety valve 81 and closes the oil outlet of the two-position three-way solenoid valve 83 connected to the second safety valve 82. This allows the first safety valve 81, with its lower pressure threshold, to protect the pipeline. Based on the same principle, the back pressure of intermediate pipelines can be adaptively reduced and adaptive control can be achieved for better pipeline protection.

[0037] In some embodiments, the second safety valve 82 is an overflow valve.

[0038] In some embodiments, reference Figure 2This application also discloses a hydraulic drive system, specifically a marine hydraulic drive system. It includes at least an oil tank 91, a working oil pump 200, a pressure oil source 92, an actuator 300, and the aforementioned active combined back pressure real-time adjustment module 100. In addition to the aforementioned components, the marine hydraulic drive system can add corresponding commonly used components in the field of marine hydraulic transmission technology according to actual operational needs, assembly requirements, and functional requirements. These components include, for example, water pressure sensors for sensing external water pressure, connecting pipes, and control valves. Further details on these components are omitted here.

[0039] In this embodiment, the oil tank 91, the working oil pump, and the actuator are connected sequentially via pipelines to form a hydraulic circuit, which drives the actuator to perform specific tasks. The return port of the hydraulic circuit is connected to the oil tank 91 via the return oil pipe 10. The pressure oil source is connected to the inlet of the oil pressure replenishment pipe 40. The pressure oil source 92 can be an independent oil supply source separate from the working oil pump. For example, the pressure oil source 92 includes a supplementary pressure oil pump, whose inlet is connected to the oil tank 91 and whose outlet is connected to the oil pressure replenishment pipe 40, thereby enabling the input of pressure oil into the oil pressure replenishment pipe 40.

[0040] In some embodiments, this application also discloses a ship including the aforementioned ship hydraulic drive system.

[0041] In some embodiments, a control method for a hydraulic drive system is also provided, the control method being applied to the hydraulic drive system as described in any of the preceding embodiments, the control method comprising: adaptively controlling the return oil pipe pressure by controlling a proportional valve, such that the return oil pipe pressure is greater than the pressure of the external environment.

[0042] Specifically, in some embodiments, the pressure of the external environment is less than a set value, less than a first pressure threshold, and less than a second pressure threshold.

[0043] In the embodiments of this application, long-term back pressure control is achieved through an accumulator. Specifically, hydraulic oil from the return pipe reaches the inlet of the proportional relief valve through a check valve. A pressure sensor provides real-time pressure feedback, which is compared with a set value. When the inlet pressure is lower than the set value, the proportional relief valve is closed, as are the first and second safety valves. At this time, the two-position, two-way solenoid directional valve opens, and an external pressure oil source pressurizes the inlet while simultaneously charging the accumulator. When the set value is reached, the two-position, two-way solenoid directional valve closes, and the accumulator maintains pressure and supplies oil to the inlet. When the inlet pressure exceeds the set value but does not exceed the pressure threshold of the safety valve, the proportional relief valve, under the action of a control signal, keeps the inlet pressure within the required range.

[0044] In the embodiments of this application, multi-level safety protection at different water depths is achieved through a first safety valve and a second safety valve. The two safety valves have different pressure thresholds: the first safety valve's pressure threshold corresponds to the water pressure at the commonly used depth, while the second safety valve is set to a higher pressure threshold. At the commonly used depth, the two-position three-way solenoid valve is in its initial state. When the inlet pressure exceeds the first pressure threshold, the first safety valve opens, protecting the pipeline system. At higher depths, the two-position three-way solenoid valve is energized and in the left position, the second safety valve operates, and it provides safety protection for the pipeline.

[0045] In the embodiments of this application, a two-position, two-way hydraulic directional valve is used to achieve safety protection against check valve jamming. When the check valve is jammed, the pressure difference between the two chambers of the check valve increases, and the two-position, two-way hydraulic directional valve is in the connected position under the action of hydraulic force, thus bypassing the check valve and ensuring the normal use of the return oil pipe back pressure function in case of failure.

[0046] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A hydraulic drive system, characterized in that, It includes at least an oil tank (91), a working oil pump (200), a pressure oil source (92), an actuator (300), a return oil pipe (10), and an active combined back pressure real-time adjustment module (100); the oil tank, the working oil pump, and the actuator are connected in sequence through pipelines to form a hydraulic circuit; the return oil port of the hydraulic circuit is connected to the oil tank through the return oil pipe; The active combined back pressure real-time adjustment module includes an oil pressure replenishment pipe (40), a first check valve (20), a second check valve (42), a proportional valve (30), a pressure sensor (60), and a controller; the first check valve (20) and the proportional valve (30) are sequentially arranged in the return oil pipe (10) along the return oil direction, so that the hydraulic oil in the return oil pipe (10) can flow sequentially through the first check valve (20) and the proportional valve (30); the return oil pipe (10) includes an intermediate pipe section (11), the outlet of the first check valve (20) and the outlet of the proportional valve (30) The oil inlet is connected through the intermediate pipe section (11); the pressure oil source (92) is connected to the oil inlet of the oil pressure replenishment pipe (40), and the oil outlet of the oil pressure replenishment pipe (40) is connected to the intermediate pipe section (11); the second one-way valve (42) is provided on the oil pressure replenishment pipe (40) to limit the one-way delivery of pressure oil by the oil pressure replenishment pipe (40); the pressure sensor (60) is configured to sense the oil pressure of the intermediate pipe section (11) in real time, and the controller is configured to receive the pressure signal of the oil pressure fed back by the pressure sensor (60) and control the proportional valve (30) according to the pressure signal.

2. The hydraulic drive system as described in claim 1, characterized in that, The active combined back pressure real-time adjustment module also includes an accumulator (51) and a one-way throttle valve (52); the oil pressure replenishment pipe (40) includes an output pipe section (41), one end of which is connected to the oil outlet of the second one-way valve (42), and the other end is connected to the intermediate pipe section (11); the accumulator (51) is connected to the output pipe section (41) through the one-way throttle valve (52).

3. The hydraulic drive system as described in claim 2, characterized in that, The active combined back pressure real-time adjustment module also includes an electromagnetic reversing valve (43), which is located on the oil pressure replenishment pipe (40) to control the opening and closing of the oil pressure replenishment pipe (40); the electromagnetic reversing valve (43) and the second one-way valve (42) are arranged sequentially along the direction of conveying pressure oil in the oil pressure replenishment pipe (40); the electromagnetic reversing valve (43) is electrically connected to the controller, and the controller controls the opening and closing of the electromagnetic reversing valve (43).

4. The hydraulic drive system as described in claim 1, characterized in that, The active combined back pressure real-time adjustment module also includes a two-position two-way hydraulic directional valve (70), which is connected in parallel with the first one-way valve (20).

5. The hydraulic drive system as described in claim 1, characterized in that, The active combined back pressure real-time adjustment module also includes a protection valve group (80), which is connected in parallel with the proportional valve (30).

6. The hydraulic drive system as described in claim 5, characterized in that, The protective valve assembly (80) includes a first safety valve (81), a two-position three-way solenoid valve (83), and a second safety valve (82); the oil inlet of the two-position three-way solenoid valve (83) is connected to the return oil pipe (10), and the two oil outlets of the two-position three-way solenoid valve (83) are respectively connected to the oil inlet of the first safety valve (81) and the oil inlet of the second safety valve (82); the two-position three-way solenoid valve (83) is electrically connected to the controller; The pressure threshold of the second safety valve (82) is higher than the pressure threshold of the first safety valve (81).

7. An active combined real-time back pressure adjustment module, characterized in that, The active combined back pressure real-time adjustment module, applied to a marine hydraulic drive system, includes a return oil pipe (10), an oil pressure replenishment pipe (40), a first check valve (20), a second check valve (42), a proportional valve (30), a pressure sensor (60), and a controller. The first check valve (20) and the proportional valve (30) are sequentially arranged in the return oil pipe (10) along the return oil direction, so that the hydraulic oil in the return oil pipe (10) can flow sequentially through the first check valve (20) and the proportional valve (30). The return oil pipe (10) includes an intermediate pipe section (11). The outlet of the first check valve (20) and the inlet of the proportional valve (30) are connected through the intermediate pipe section (11); the outlet of the oil pressure replenishment pipe (40) is connected to the intermediate pipe section (11); the second check valve (42) is provided on the oil pressure replenishment pipe (40) to limit the one-way delivery of pressure oil in the oil pressure replenishment pipe (40); the pressure sensor (60) is configured to sense the oil pressure of the intermediate pipe section (11) in real time; the controller is configured to receive the pressure signal of the oil pressure fed back by the pressure sensor (60) and control the proportional valve (30) according to the pressure signal.

8. The active combined back pressure real-time adjustment module as described in claim 7, characterized in that, The active combined back pressure real-time adjustment module also includes an accumulator (51) and a one-way throttle valve (52); the oil pressure replenishment pipe (40) includes an output pipe section (41), one end of which is connected to the oil outlet of the second one-way valve (42), and the other end is connected to the intermediate pipe section (11); the accumulator (51) is connected to the output pipe section (41) through the one-way throttle valve (52). The active combined back pressure real-time adjustment module includes a first safety valve (81), a two-position three-way solenoid valve (83), and a second safety valve (82); the oil inlet of the two-position three-way solenoid valve (83) is connected to the return oil pipe (10), and the two oil outlets of the two-position three-way solenoid valve (83) are respectively connected to the oil inlet of the first safety valve (81) and the oil inlet of the second safety valve (82); the two-position three-way solenoid valve (83) is electrically connected to the controller; The first safety valve (81), the second safety valve (82) and the proportional valve (30) are connected in parallel, and the pressure threshold of the second safety valve (82) is higher than the pressure threshold of the first safety valve (81).

9. A hydraulic drive system, characterized in that, It includes at least an oil tank (91), a working oil pump, a pressure oil source (92), an actuator, and an active combined back pressure real-time adjustment module as described in any one of claims 7-8; the oil tank (91), the working oil pump, and the actuator are connected in sequence through pipelines to form a hydraulic circuit; the return port of the hydraulic circuit is connected to the oil tank (91) through the return oil pipe (10); the pressure oil source (92) is connected to the inlet of the oil pressure supplement pipe (40).

10. A control method for a hydraulic drive system, characterized in that, The control method is applied to the hydraulic drive system as described in any one of claims 1-6 and 9, and the control method includes: The pressure in the return oil pipe is adaptively controlled by controlling the proportional valve, so that the pressure in the return oil pipe is greater than the pressure of the external environment.

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