Hydraulic control system for underwater work equipment

Abstract

The hydraulic control system for underwater operation equipment provided by the present disclosure belongs to the technical field of hydraulic drive, and comprises a pump group, a reversing valve and a control valve group. The oil inlet of the reversing valve is connected with the oil outlet of the pump group, the oil return port of the reversing valve is connected with an oil tank, the first working oil port of the reversing valve is connected with the rod cavity of an execution cylinder, the second working oil port of the reversing valve is connected with the rodless cavity of the execution cylinder, and the first working oil port and the second working oil port of the reversing valve are both connected with the control valve group. The control valve group is connected with the rod cavity and the rodless cavity of the execution cylinder respectively, and is used for controlling the execution cylinder to output constant force when the reversing valve controls the execution cylinder to extend or retract. The present disclosure can make the output torque of the execution cylinder not affected by water pressure, thereby improving the safety of underwater operation equipment and the like.

Description

Technical Field

[0001] This disclosure belongs to the field of hydraulic drive technology, and particularly relates to a hydraulic control system for underwater operation equipment. Background Technology

[0002] With the continuous deepening of deep-sea exploration and marine resource development, the performance requirements for underwater operation equipment are increasing. Especially in the fields of underwater construction, seabed oil and gas extraction, and deep-sea scientific research, precise control of the position and attitude of underwater operation equipment is the key to achieving efficient and safe operations.

[0003] In related technologies, underwater work equipment is typically controlled by a hydraulic control system during operation. This system includes control valve assemblies and hydraulic cylinders. The hydraulic cylinders are connected to the underwater work equipment. The control valve assemblies are connected to the hydraulic cylinders to drive them to extend or retract, thereby enabling the underwater work equipment to perform its tasks.

[0004] However, after the actuator cylinder is connected to the underwater work equipment, it moves synchronously with the equipment in the water. As the actuator cylinder moves with the equipment, the water depth and water pressure at its location change. During operation, the piston's extension and retraction are affected by the varying water depth, impacting the actual output torque. For example, when the piston extends, the actual output torque is the theoretical output torque minus the torque corresponding to the water pressure (the theoretical output torque minus the torque corresponding to the water pressure). When the piston retracts, the actual output torque is the theoretical output torque plus the torque corresponding to the water pressure. Therefore, the actual output torque changes depending on the actuator cylinder's position, thus affecting the safety of the underwater work equipment. Summary of the Invention

[0005] This disclosure provides a hydraulic control system for underwater operating equipment, which ensures that the actual output torque of the actuator cylinder is unaffected by water pressure, thereby improving the safety of the underwater operating equipment. The technical solution is as follows:

[0006] This disclosure provides a hydraulic control system for underwater operating equipment. The hydraulic control system drives an actuator cylinder to extend or retract, and the actuator cylinder is connected to the underwater operating equipment. The hydraulic control system includes a pump group, a directional valve, and a control valve group. The inlet of the directional valve is connected to the outlet of the pump group, and the return port of the directional valve is connected to an oil tank. The first working port of the directional valve is connected to the rod chamber of the actuator cylinder, and the second working port of the directional valve is connected to the rodless chamber of the actuator cylinder. Both the first and second working ports of the directional valve are connected to the control valve group. The control valve group is connected to both the rod chamber and the rodless chamber of the actuator cylinder, and is used to control the actuator cylinder to output a constant force while the directional valve controls the extension or retraction of the actuator cylinder.

[0007] In another implementation of this disclosure, the cross-sectional area of ​​the piston rod of the actuator cylinder is 1 / n of the cross-sectional area of ​​the rodless chamber of the actuator cylinder, where n is a positive number greater than 1; the control valve group includes a cartridge valve, a first hydraulically controlled directional valve, and a pressure control unit; the first port of the cartridge valve is connected to the inlet port of the first hydraulically controlled directional valve, the second port of the cartridge valve is connected to the second working port of the directional valve, and the area of ​​the control port of the cartridge valve is m times the area of ​​the second port of the cartridge valve, where m is a positive number not less than 1; the first working port of the first hydraulically controlled directional valve is connected to the rod chamber of the actuator cylinder. The second working port of the first hydraulic directional valve is connected to the rodless chamber of the actuator cylinder, and the return port of the first hydraulic directional valve is connected to the oil tank. The pressure control unit is connected to the outlet port of the first pump group, the oil tank, and the control port of the cartridge valve. The pressure control unit is used to control the actual output oil pressure of the pump group to be the sum of the theoretical output oil pressure of the pump group and the seawater pressure when the actuator cylinder extends, and to make the control port of the cartridge valve connected to the oil tank. Alternatively, the pressure control unit is used to control the oil pressure at the control port of the cartridge valve to be 1 / nm of the seawater pressure when the actuator cylinder retracts.

[0008] In another implementation of this disclosure, the pressure control unit includes a pressure regulating device, a second hydraulically controlled directional valve, a flexible container, and an overflow valve; the oil inlet of the pressure regulating device is connected to the control port of the cartridge valve, the oil outlet of the pressure regulating device is connected to the first working port of the second hydraulically controlled directional valve, the control port of the second hydraulically controlled directional valve is connected to the second working port of the directional valve, the oil inlet of the second hydraulically controlled directional valve is connected to the flexible container, and the oil return port of the second hydraulically controlled directional valve is connected to the oil tank; the flexible container contains oil, the oil inlet of the overflow valve is connected to the oil outlet of the pump unit and the oil inlet of the directional valve, the oil return port of the overflow valve is connected to the oil tank, and the control port of the overflow valve is connected to the second working port of the second hydraulically controlled directional valve; the flexible container can deform under water pressure, allowing the internal oil to flow out under water pressure.

[0009] In another implementation of this disclosure, the flexible container is either a rubber bladder or a leather bladder.

[0010] In another implementation of this disclosure, the pressure regulating device is one of a pressure reducing valve, a hydraulic cylinder, or a throttle tube.

[0011] In another implementation of this disclosure, the hydraulic control system further includes a hydraulic lock, which comprises a first hydraulically controlled check valve and a second hydraulically controlled check valve. The inlet of the first hydraulically controlled check valve is connected to the first working port of the directional valve and the first working port of the first hydraulically controlled directional valve, respectively. The outlet of the first hydraulically controlled check valve is connected to the rod chamber of the actuator cylinder, and the control port of the first hydraulically controlled check valve is connected to the inlet of the second hydraulically controlled check valve. The inlet of the second hydraulically controlled check valve is connected to the second port of the cartridge valve and the second working port of the first hydraulically controlled directional valve, respectively. The outlet of the second hydraulically controlled check valve is connected to the rodless chamber of the actuator cylinder, and the control port of the second hydraulically controlled check valve is connected to the inlet of the first hydraulically controlled check valve.

[0012] In another implementation of this disclosure, the hydraulic control system further includes a first check valve, which is connected between the directional valve and the hydraulic lock. The inlet of the first check valve is connected to the first working port of the directional valve, and the outlet of the first check valve is connected to the inlet of the first hydraulically controlled check valve.

[0013] In another implementation of this disclosure, the hydraulic control system further includes a second check valve, which is connected between the directional valve and the cartridge valve. The inlet of the second check valve is connected to the second working port of the directional valve, and the outlet of the second check valve is connected to the second port of the cartridge valve.

[0014] In another implementation of this disclosure, the hydraulic control system further includes a third check valve, which is connected between the second hydraulically controlled check valve and the cartridge valve. The inlet of the third check valve is connected to the outlet of the second hydraulically controlled check valve, and the outlet of the third check valve is connected to the second port of the cartridge valve and the outlet of the second check valve, respectively.

[0015] In another implementation of this disclosure, the directional valve is a three-position four-way electromagnetic proportional directional valve.

[0016] The beneficial effects of the technical solutions provided in this disclosure are:

[0017] Since the control valve assembly is connected to the directional valve, it is used to ensure that the actuator cylinder outputs a constant force when it extends or retracts. In this way, the control valve assembly can ensure that the actuator cylinder always outputs a constant force when the directional valve drives the actuator cylinder to extend or retract, thereby making the driving force on the underwater equipment stable when the actuator cylinder extends or retracts, which greatly improves the safety of the underwater equipment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a hydraulic control system for underwater equipment.

[0020] Figure 2 This is a schematic diagram of another hydraulic control system used in underwater equipment.

[0021] The symbols in the diagram represent the following meanings:

[0022] 1. Pump set; 11. Drive pump; 12. Motor;

[0023] 2. Reversing valve;

[0024] 3. Control valve assembly; 31. Cartridge valve; 32. First hydraulically controlled directional valve; 34. Pressure control unit; 341. Pressure regulating device; 342. Second hydraulically controlled directional valve; 343. Flexible container; 345. Relief valve;

[0025] 5. Hydraulic lock; 51. First hydraulically controlled check valve; 52. Second hydraulically controlled check valve;

[0026] 6. First check valve; 7. Second check valve; 8. Third check valve;

[0027] 100. Execution cylinder. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0029] This disclosure provides a hydraulic control system for underwater operating equipment, such as... Figure 1 As shown, the hydraulic control system is used to drive the actuator cylinder 100 to extend or retract, and the actuator cylinder 100 is used to connect to the underwater operation equipment.

[0030] The hydraulic control system includes a pump assembly 1, a directional valve 2, and a control valve assembly 3. The inlet of the directional valve 2 is connected to the outlet of the pump assembly 1, and the return port of the directional valve 2 is connected to the oil tank. Both the first working port a and the second working port b of the directional valve 2 are connected to the control valve assembly 3. The control valve assembly 3 is connected to the rod-side and rodless-side chambers of the actuator 100, respectively, and is used to control the actuator 100 to output a constant force when the directional valve 2 controls the actuator 100 to extend or retract.

[0031] When the hydraulic control system provided in this embodiment drives the underwater working equipment, since the hydraulic control system includes a pump set 1 and a reversing valve 2, oil can be supplied to the reversing valve 2 through the pump set 1.

[0032] Since the control valve assembly 3 is connected to the first and second working ports of the directional valve 2 respectively, and is used to control the output of the actuator 100 to maintain a constant force when the actuator 100 extends or retracts, the control valve assembly 3 ensures that the actuator 100 always outputs a constant force when the directional valve 2 drives the actuator 100 to extend or retract. This results in a stable driving force on the underwater equipment when the actuator extends or retracts, greatly improving the safety of the underwater equipment.

[0033] Figure 2 This is a schematic diagram of another hydraulic control system used in underwater work equipment, combined with... Figure 2 Optionally, the reversing valve 2 is a three-position four-way proportional reversing valve.

[0034] In the above implementation, the three-position four-way proportional directional valve can steplessly adjust the valve core position of the directional valve 2 so that the moving speed of the actuator cylinder 100 is constant.

[0035] In this embodiment, when the valve core of the reversing valve is in Figure 2When the directional control valve 2 is in the left position, the inlet p of the directional control valve 2 is connected to the first working port a, and the return port t of the directional control valve 2 is connected to the second working port b. At this time, the oil enters the rod chamber of the actuator cylinder 100 through the first working port a of the directional control valve 2, driving the actuator cylinder 100 to retract. At the same time, the oil in the rodless chamber of the actuator cylinder 100 flows back to the oil tank through the control valve group 3.

[0036] Conversely, when the valve core of directional valve 2 is in Figure 2 When the oil is in the right position, the oil inlet p of the reversing valve 2 is connected to the second working oil port b, and the oil return port t of the reversing valve 2 is connected to the first working oil port a. At this time, the oil enters the control valve group 3 through the second working oil port b of the reversing valve 2, and then enters the rodless chamber of the actuator cylinder 100 after passing through the control valve group 3, driving the actuator cylinder 100 to extend.

[0037] In this embodiment, the valve core of the reversing valve 2 can be in the left position, the right position, or the neutral position. When the valve core of the reversing valve 2 is in the neutral position, the oil inlet p, the oil return t, the first working oil port a, and the second working oil port b of the reversing valve 2 are all interconnected. The high-pressure oil entering the reversing valve 2 flows directly back to the oil tank, and the hydraulic cylinder 100 does not operate.

[0038] Optionally, the cross-sectional area of ​​the piston rod of the actuator cylinder 100 is 1 / n of the cross-sectional area of ​​the rodless chamber of the actuator cylinder. Wherein, n is a positive number greater than 1.

[0039] The control valve assembly 3 includes a cartridge valve 31, a first hydraulically controlled directional valve 32, and a pressure control unit 34. The first port a of the cartridge valve 31 is connected to the inlet p of the first hydraulically controlled directional valve 32, and the second port b of the cartridge valve 31 is connected to the second working port b of the directional valve 32. The area of ​​the control port x of the cartridge valve 31 is m times the area of ​​the second port b of the cartridge valve 31, where m is a positive number greater than 1.

[0040] The first working port a of the first hydraulic directional valve 32 is connected to the rod chamber of the actuator cylinder 100. The second working port b of the first hydraulic directional valve 32 is connected to the rodless chamber of the actuator cylinder 100, and the return port t of the first hydraulic directional valve 32 is connected to the oil tank.

[0041] The first hydraulic directional valve 32 is configured such that when the pressure in its control chamber is greater than the spring force in its spring chamber, the first working port a, the second working port b, and the inlet p of the first hydraulic directional valve 32 are all connected (i.e., Figure 2The corresponding valve core of the first hydraulic directional valve 32 is in the left position. When the pressure in its control chamber is not greater than the spring force in its spring chamber, the return port t and the inlet port p of the first hydraulic directional valve 32 are connected, and the first working port a and the second working port b of the first hydraulic directional valve 32 are disconnected from each other and are not connected to the inlet port P or the return port t (that is...). Figure 2 The valve core of the corresponding first hydraulic directional valve 32 is in the right position.

[0042] The pressure control unit 34 is connected to the oil outlet of the first pump group 1, the oil tank, and the control port of the cartridge valve 31. The pressure control unit 34 controls the actual output oil pressure of the pump group 1 to be the sum of the theoretical output oil pressure of the pump group 1 and the seawater pressure when the actuator cylinder 100 extends, and ensures that the control port of the cartridge valve 31 is connected to the oil tank. Alternatively, the pressure control unit 34 can control the oil pressure at the control port of the cartridge valve 31 to be 1 / nm of the seawater pressure when the actuator cylinder 100 retracts.

[0043] In the above implementation, when the valve core of the reversing valve 2 is in the right position, the return port t of the reversing valve 2 is connected to the second working port b, and the inlet port p of the reversing valve 2 is connected to the first working port a. At this time, the high-pressure oil output by the pump unit 1, after passing through the second working port b of the reversing valve 2, a portion of the oil enters the control port x of the first hydraulically controlled reversing valve 32. The first hydraulically controlled reversing valve 32 is in the left position. The inlet port p of the first hydraulically controlled reversing valve 32 is connected to both the first working port a and the second working port b. The high-pressure oil output by the pump unit 1, after passing through the second working port b of the reversing valve 2, another portion of the oil (i.e., the oil in the main oil circuit) flows to the cartridge valve 31. The oil in the control port x of the cartridge valve 31 is unloaded into the oil tank through the pressure control unit 34. The main oil circuit oil opens the cartridge valve 31 through the second port b. After passing through the first port a of the cartridge valve 31, the hydraulic fluid enters the first hydraulically controlled directional valve 32. The hydraulic fluid then flows through the inlet p of the first hydraulically controlled directional valve 32 to the rod-side and rodless-side chambers of the actuator cylinder 100. Since the cross-sectional area A0 of the piston rod of the actuator cylinder is equal to 1 / n of the cross-sectional area A1 of the rodless-side chamber (that is, A0 = A1 / n), the hydraulic fluid enters the rodless-side chamber, pushing the piston rod of the actuator cylinder 100 outward. Simultaneously, the hydraulic fluid in the rod-side chamber of the actuator cylinder flows through the first hydraulically controlled directional valve 32 to the rodless-side chamber of the actuator cylinder 100. At this time, the actual working area of ​​the actuator cylinder 100 when it extends is the cross-sectional area A0 of the piston rod.

[0044] Since the pressure control unit 34 can control the actual output oil pressure of the pump set 1 to be the sum of the theoretical oil pressure of the pump set 1 and the seawater pressure when the hydraulic cylinder 100 extends, the actual output oil pressure of the pump set 1 at this time is the theoretical oil pressure plus the seawater pressure (i.e., P). 理 +P 海水At this time, the oil pressure of hydraulic cylinder 100 is P. 理 +P 海水 .

[0045] Since the working area of ​​the oil chamber in the actuator cylinder multiplied by the working pressure equals the output force of the actuator cylinder, the output force of the actuator cylinder is A0×(P). 理 +P 海水 ).

[0046] When the piston rod of the hydraulic cylinder extends, it needs to overcome external water pressure. The force exerted by the external water pressure is:

[0047] A0×P 海水 ;

[0048] The actual output force of the hydraulic cylinder satisfies the following formula:

[0049] F 输出 =A0×(P 理 +P 海水 )-A0×P 海水 =A0× 理 (1)

[0050] Among them, F 输出 To generate the output force of the hydraulic cylinder; A0 is the cross-sectional area of ​​the piston rod; P 理 P represents the theoretical output oil pressure of pump unit 1. 海水 The pressure of seawater.

[0051] When the valve core of the reversing valve 2 is in the left position, the oil from the pump unit 1 flows through the inlet P of the reversing valve 2 to the first working port a, and then enters the rod chamber of the actuator cylinder 100. The actuator cylinder 100 retracts. The oil in the rodless chamber of the actuator cylinder 100 reaches the second port b of the cartridge valve 31, overcomes the back pressure of the control port x of the cartridge valve 31, and flows back to the oil tank through the first hydraulically controlled reversing valve 32.

[0052] Since the first port a of the cartridge valve 31 is connected to the oil tank through the first hydraulic directional valve 32, the pressure at the first port a of the cartridge valve 31 is 0. At this time, for the cartridge valve 31 to open, the oil pressure at the second port b of the cartridge valve 31 must be equal to the oil pressure at the control port x of the cartridge valve 31.

[0053] Therefore, cartridge valve 31 satisfies the following formula:

[0054] P b ×S b =P x ×S x (2)

[0055] Wherein, Sb is the area of ​​the second port b of the cartridge valve 31; Pb is the oil pressure of the second port b of the cartridge valve 31; Px is the oil pressure of the control port x of the cartridge valve 31; and Sx is the area of ​​the control port x of the cartridge valve 31.

[0056] Since the area Sx of the control port x of the cartridge valve 31 is equal to m times the area Sb of the second port b, i.e., Sx = mSb, formula (2) can be transformed into:

[0057] P b =mP x (3)

[0058] Furthermore, because the pressure control unit 34 controls the oil pressure at the control port of the cartridge valve 31 to be 1 / nm of the seawater pressure when the actuator cylinder 100 retracts. That is, at this time, the oil pressure at the control port x of the cartridge valve 31 is 1 / nm of the seawater pressure, which means;

[0059] P x =P 海水 / nm.

[0060] Therefore, formula (3) can be transformed into formula (4):

[0061]

[0062] Since the second port b of the cartridge valve 31 is connected to the rodless chamber in the actuator cylinder 100, the oil pressure at the second port b of the cartridge valve 31 is equal to the oil pressure in the rodless chamber of the actuator cylinder 100.

[0063] The output force of the hydraulic cylinder is the pressure in the rod chamber minus the pressure in the rodless chamber:

[0064]

[0065] Among them, F 输出 To generate the output force of the hydraulic cylinder; A0 is the cross-sectional area of ​​the piston rod; A1 is the area of ​​the rodless chamber; P 理 P represents the theoretical output oil pressure of pump unit 1. 海水 The pressure of seawater.

[0066] Since A1 = nA0, formula (5) can be transformed into the following formula (6):

[0067]

[0068] When the piston rod of the hydraulic cylinder retracts, it is subjected to external water pressure. The force exerted by the external water pressure is A0×P. 海水 Therefore, the actual output force of the hydraulic cylinder satisfies the following formula:

[0069] F 实际输出=A0(P 理 -P 海水 )+A0P 海水 =A0×P 理 (7)

[0070] Therefore, it can be seen that the actual output force of the hydraulic cylinder is A0P when it extends or retracts. 理 .

[0071] In this embodiment, the theoretical output oil pressure of pump set 1 refers to the oil pressure at the output end of pump set 1. The actual output oil pressure of pump set 1 refers to the oil pressure in the actuator cylinder 100 after the oil output from pump set 1 enters the actuator cylinder 100 when the actuator cylinder 100 extends or retracts.

[0072] In this embodiment, the area Sx of the control port x of the cartridge valve 31 mentioned above is equal to m times the area Sb of the second port b. Here, Sx and Sb both refer to the flow area of ​​the corresponding port.

[0073] Optionally, the pressure control unit 34 includes a pressure regulating device 341, a second hydraulically controlled directional valve 342, a flexible container 343, and a relief valve 345. The first port of the pressure regulating device 341 is connected to the control port of the cartridge valve 31; the second port of the pressure regulating device 341 is connected to the first working port of the second hydraulically controlled directional valve 342; the control port of the second hydraulically controlled directional valve 342 is connected to the second working port of the directional valve 342; the inlet port of the second hydraulically controlled directional valve 342 is connected to the flexible container 343; and the return port of the second hydraulically controlled directional valve 342 is connected to the oil tank. The inlet port of the relief valve 345 is connected to both the outlet port of the pump unit 1 and the inlet port of the directional valve 2; the return port of the relief valve 345 is connected to the oil tank; and the control port of the relief valve 345 is connected to the second working port of the second hydraulically controlled directional valve 342. The flexible container 343 contains oil, and the flexible container 343 can deform under water pressure, causing the oil inside to flow out under water pressure.

[0074] The second hydraulic directional valve 342 is configured such that, when the pressure in its control chamber is greater than the spring force in its spring chamber, both the second working port b and the inlet port p of the second hydraulic directional valve 342 are connected, and the first working port a is connected to the return port t (that is...). Figure 2 (The left position corresponding to the second hydraulic directional valve 342). When the pressure in the control chamber of the second hydraulic directional valve 342 is not greater than the spring force in its spring chamber, the second working port b of the first hydraulic directional valve 32 is connected to the return port t, and the first working port a is connected to the inlet port p (that is... Figure 2(Right position corresponding to the second hydraulically controlled directional valve 342). In the above implementation, the pressure regulating device 341 is used to reduce pressure. The cooperation between the second hydraulically controlled directional valve 342 and the flexible container 343 is used to introduce seawater pressure into the system. The overflow valve 345 is used to limit the system pressure, that is, to control the theoretical output oil pressure of the pump group 1.

[0075] In this embodiment, for ease of calculation, n=2, m=1, and the oil pressure at the second oil port of the pressure regulating device 341 is equal to half the oil pressure at the first oil port.

[0076] For example, the pressure regulating device 341 can be one of a pressure reducing valve, a hydraulic cylinder, a throttle tube, etc. It is acceptable as long as the ratio of the oil pressure between the first oil port and the second oil port in the pressure regulating device 341 is 1:nm.

[0077] When the pressure regulating device 341 is a hydraulic cylinder, the ratio of the working area of ​​the rodless cavity to the working area of ​​the rod cavity can be designed to be n:m, which can achieve a ratio of 1:nm between the oil pressure of the first oil port and the second oil port in the pressure regulating device 341. The first oil port in the pressure regulating device 341 is the output end of the rod cavity, and the second oil port is the output end of the rodless cavity.

[0078] With the pressure control unit 34 configured as described above, when the actuator cylinder 100 extends, the oil inside the flexible container 343 flows through the second hydraulically controlled directional valve 342 to the control port x of the overflow valve 345 under the pressure of seawater. Therefore, the maximum oil pressure at the inlet a of the overflow valve 345 is the sum of the set pressure of its own spring chamber and the seawater pressure. The maximum oil pressure at the inlet a of the overflow valve 345 is the rated oil pressure of the pump group 1 entering the actuator cylinder 100. Thus, the rated oil pressure of the actuator cylinder 100 is the sum of the set pressure of the overflow valve 345 and the seawater pressure. In other words, when the actuator cylinder 100 extends (after the actuator cylinder 100 extends, the corresponding oil pressure is also the rated oil pressure, and the thrust provided by the actuator cylinder 100 is at its maximum value), the actual output oil pressure of the pump group 1 is the sum of the theoretical output oil pressure of the pump group 1 and the seawater pressure. Furthermore, since the control oil port of the cartridge valve 31 flows back to the oil tank after passing through the second hydraulic directional valve 342, the control oil port of the cartridge valve 31 is connected to the oil tank.

[0079] When the hydraulic cylinder 100 retracts, the oil in the rodless chamber of the hydraulic cylinder 100 reaches the second port b of the cartridge valve 31, overcomes the back pressure of the control port x of the cartridge valve 31, and flows back to the oil tank through the first hydraulically controlled directional valve 32. The oil inside the flexible container 343, under the pressure of seawater, is connected to the control port x of the cartridge valve 31 through the second hydraulically controlled directional valve 342, the pressure regulating device 341, and the control port x of the cartridge valve 31. Since the ratio of the oil pressure at the first port to the second port in the pressure regulating device 341 is 1 / nm, and the oil pressure at the control port of the cartridge valve 31 is the same as the oil pressure at the second port (because the area of ​​the control port in the cartridge valve 31 is m times the area of ​​the second port, and m = 1, so the area of ​​the control port in the cartridge valve 31 is the same as the area of ​​the second port, while the oil pressure at the first port is 0), the oil pressure at the control port x of the cartridge valve 31 is P. 海水 / nm. It is evident that configuring the voltage control unit 34 with the above structure satisfies the above requirements.

[0080] In other examples, the pressure control unit 34 can also have other structures, such as a combination of a control valve, a relief valve, and a pressure regulating device. When the cylinder 100 extends, the control valve connects the control port of the cartridge valve 31 to the oil tank, and the relief valve regulates the output pressure of the pump group 1. When the cylinder 100 retracts, the pressure regulating device controls the oil pressure at the control port of the cartridge valve 31 to 1 / nm of the seawater pressure.

[0081] Optionally, the flexible container 343 can be either a rubber bladder or a leather bladder. In this way, the flexible container 343 can deform rapidly under water pressure, thereby squeezing out the oil inside.

[0082] Optionally, the control system further includes a hydraulic lock 5, which includes a first hydraulically controlled check valve 51 and a second hydraulically controlled check valve 52. The inlet of the first hydraulically controlled check valve 51 is connected to the first working port of the directional valve 2 and the first working port of the first hydraulically controlled directional valve 32, respectively. The outlet of the first hydraulically controlled check valve 51 is connected to the rod chamber of the actuator cylinder 100, and the control port of the first hydraulically controlled check valve 51 is connected to the inlet of the second hydraulically controlled check valve 52. The inlet of the second hydraulically controlled check valve 52 is connected to the second port of the cartridge valve 31 and the second working port of the first hydraulically controlled directional valve 32, respectively. The outlet of the second hydraulically controlled check valve 52 is connected to the rodless chamber of the actuator cylinder 100, and the control port of the second hydraulically controlled check valve 52 is connected to the inlet of the first hydraulically controlled check valve 51.

[0083] In the above implementation, the first hydraulic check valve 51 and the second hydraulic check valve 52 can form a hydraulic lock. In this way, when the actuator cylinder 100 is not in motion, the oil in the rodless chamber and the rod chamber of the actuator cylinder 100 can be locked to prevent the actuator cylinder 100 from depressurizing and causing a safety accident to the underwater operation equipment.

[0084] Optionally, the hydraulic control system further includes a first check valve 6, which is connected between the directional valve 2 and the hydraulic lock 5. The oil inlet of the first check valve 6 is connected to the first working oil port of the directional valve 2, and the oil outlet of the first check valve 6 is connected to the oil inlet of the first hydraulically controlled check valve 51.

[0085] In the above implementation, the first check valve 6 is used to restrict the flow of oil in the oil circuit between the directional valve 2 and the hydraulic lock 5, so that the oil can only flow from the directional valve to the hydraulic lock 5.

[0086] Optionally, the hydraulic control system further includes a second check valve 7, which is connected between the directional valve 2 and the cartridge valve 31. The oil inlet of the second check valve 7 is connected to the second working oil port of the directional valve 2, and the oil outlet of the second check valve 7 is connected to the second oil port b of the cartridge valve 31.

[0087] In the above implementation, the second check valve 7 is used to restrict the flow of oil in the oil circuit between the reversing valve 2 and the cartridge valve 31, so that the oil can only flow from the reversing valve 2 to the second oil port b of the cartridge valve 31.

[0088] Optionally, the hydraulic control system further includes a third check valve 8, which is connected between the second hydraulically controlled check valve 52 and the cartridge valve 31. The oil inlet of the third check valve 8 is connected to the oil outlet of the second hydraulically controlled check valve 52, and the oil outlet of the third check valve 8 is connected to the second oil port of the cartridge valve 31 and the oil outlet of the second check valve 7, respectively.

[0089] In the above implementation, the third check valve 8 is used to restrict the flow of oil in the oil circuit between the second hydraulic check valve 52 and the cartridge valve 31, so that the oil can only flow from the second hydraulic check valve 52 to the second port b of the cartridge valve 31.

[0090] Optionally, the pump set 1 includes a drive pump 11 and a motor 12. The output end of the motor 12 is connected to the drive pump 11, and the oil suction port of the drive pump 11 is connected to the oil tank.

[0091] In the above implementation, motor 12 is used to drive drive pump 11 to rotate. Drive pump 11 is used to output oil from the oil tank to the reversing valve.

[0092] The working process of the hydraulic system provided in this embodiment is briefly described below:

[0093] (1) The process of outputting constant force when the piston rod of hydraulic cylinder 100 extends:

[0094] When directional valve 2 switches from the neutral position to the right position, a small amount of oil from pump unit 1 flows through directional valve 2 to the control port x of the first hydraulically controlled directional valve 32 and the control port x of the second hydraulically controlled directional valve 342. At this time, both the first hydraulically controlled directional valve 32 and the second hydraulically controlled directional valve 342 are in the left position. The inlet p of the second hydraulically controlled directional valve 342 is connected to the second working port b, and the first working port a is connected to the return port t. The inlet p of the first hydraulically controlled directional valve 32 is connected to both the first working port a and the second working port b. The main oil circuit opens the second check valve 7 and flows to the cartridge valve 31. The control port x of the cartridge valve 31 is unloaded into the oil tank through the pressure regulating device 341 and the first working port a of the second hydraulic directional valve 342. The main oil circuit opens the cartridge valve 31 through the second port b and flows to the working ports a and b of the hydraulic lock 5 through the inlet p of the first hydraulic directional valve 32. The first hydraulic check valve 51 and the second hydraulic check valve 52 of the hydraulic lock 5 are both open under high pressure.

[0095] Since the cross-sectional area A0 of the piston rod of the actuator cylinder 100 is equal to 1 / n of the cross-sectional area A1 of the rodless chamber, and n = 2, the effective area A1 of the rodless chamber of the actuator cylinder 100 is twice the effective area A2 of the rod chamber. Under the same oil pressure, the larger the area, the greater the force. Therefore, oil will enter the rodless chamber, pushing the piston rod of the actuator cylinder 100 outward. At the same time, the oil in the rod chamber of the actuator cylinder 100 flows back to the rodless chamber of the actuator cylinder 100 through the hydraulic lock 5 and the first hydraulically controlled directional valve 32 to accelerate the extension speed of the piston rod. At this time, when the actuator cylinder 100 extends, the effective area of ​​the piston rod is A1 - A2 = A2 = A0.

[0096] Under the pressure of seawater, the oil inside the flexible container 343 flows through the second hydraulically controlled directional valve 342 to the control port x of the overflow valve 345. Therefore, the maximum oil pressure at the inlet a of the overflow valve 345 is the sum of its own spring chamber setting pressure and the seawater pressure. The maximum oil pressure at the inlet a of the overflow valve 345 is the same as the oil pressure output from the pump unit 1 entering the actuator cylinder 100. Thus, the rated oil pressure of the actuator cylinder 100 is the sum of the setting pressure of the overflow valve 345 and the seawater pressure, which is:

[0097] P 溢 +P 海水 (8)

[0098] Among them, P 溢 The set oil pressure for relief valve 345; P 海水 The pressure is the seawater pressure.

[0099] The output force of the hydraulic cylinder 100 is the working area of ​​the oil chamber multiplied by the working pressure, that is, the maximum output force of the hydraulic cylinder 100 is:

[0100] A2(P 溢 +P 海水 (9)

[0101] When the piston rod of hydraulic cylinder 100 extends, it needs to overcome external water pressure. The force of the external water pressure is A² × P. 海水 The actual thrust of the hydraulic cylinder 100 when it extends is:

[0102] A×(P 溢 +P 海水 )-A2×P 海水 =A2×P 溢 (10)

[0103] When the directional valve returns from the right position to the neutral position, the control port x of the second hydraulic directional valve 342 and the control port x of the first hydraulic directional valve 32 flow back to the oil tank through the directional valve to unload. At this time, both the first hydraulic directional valve 32 and the second hydraulic directional valve 342 are reset.

[0104] (2) The process of outputting constant force when the piston rod of hydraulic cylinder 100 retracts:

[0105] When the directional valve 2 switches from the neutral position to the left position, the oil in the pump unit 1 flows through the inlet P port of the directional valve to the first working port a, and then through the first check valve 6 to the hydraulic lock 5. The oil flows through the first hydraulically controlled check valve 51 of the hydraulic lock 5 to the rod chamber of the actuator cylinder 100. At the same time, the second hydraulically controlled check valve 52 of the hydraulic lock 5 is opened. The actuator cylinder 100 retracts under the action of the oil pressure in the rod chamber. The oil in the rodless chamber of the actuator cylinder 100 reaches the second port b of the cartridge valve 31 through the second hydraulically controlled check valve 52 and the third check valve 8 of the hydraulic lock 5. It overcomes the back pressure of the control port x of the cartridge valve 31 and flows back to the oil tank through the first hydraulically controlled directional valve 32.

[0106] The oil inside the flexible container 343, under the pressure of seawater, is connected to the control port x of the cartridge valve 31 via the second hydraulically controlled directional valve 342, the pressure regulating device 341, and the control port x of the cartridge valve 31. Therefore, the pressure at the control port x of the cartridge valve 31 is:

[0107] P 海水 / nm; (11)

[0108] In this embodiment, n = 2, m = 1, which is P 海水 / 2.

[0109] According to the conditions under which cartridge valve 31 is opened, the oil pressure at the second port b of cartridge valve 31 is P. 海水 / 2. The oil pressure at the second port of the cartridge valve 31 is equal to the oil pressure in the rodless chamber of the actuator cylinder 100. The oil pressure in the rodless chamber of the actuator cylinder 100 is P. 海水 / 2.

[0110] The control port x of the relief valve 345 is connected to the oil tank through the second hydraulic directional valve 342. At this time, the oil pressure of the actuator cylinder 100 is the set pressure of the relief valve, i.e., P. 溢 .

[0111] The output force of the actuator cylinder 100 is the product of the rod chamber oil pressure and the working area of ​​the oil chamber, minus the product of the rodless chamber working area and the rodless chamber oil pressure. In other words, the output force of the actuator cylinder 100 is:

[0112] A2×P 溢 -A1×P 海水 / 2=A2×(P 溢 -P 海水 (12)

[0113] When the piston rod of the hydraulic cylinder retracts, it is subjected to external water pressure. The force exerted by the external water pressure is A² × P. 海水 The actual output force of hydraulic cylinder 100 is:

[0114] A2×(P 溢 -P 海水 )+A2×P 海水 =A2×P 溢 (13)

[0115] Based on the above analysis, the actual output force of the hydraulic cylinder 100 during its extension and retraction actions is A2×P. 海水 With the same output force and unaffected by external water pressure, the actuator 100 can adapt to changes in seawater depth.

[0116] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A hydraulic control system for an underwater work apparatus, characterized by, The hydraulic control system is used to drive the actuator cylinder (100) to extend or retract, and the actuator cylinder (100) is used to connect to underwater operating equipment; The hydraulic control system includes a pump group (1), a reversing valve (2) and a control valve group (3). The oil inlet of the reversing valve (2) is connected to the oil outlet of the pump group (1), the oil return port of the reversing valve (2) is connected to the oil tank, and the first working oil port and the second working oil port of the reversing valve (2) are both connected to the control valve group (3). The control valve group (3) is connected to the rod chamber and the rodless chamber of the actuator (100) respectively, and is used to control the actuator (100) to output a constant force while the reversing valve (2) controls the actuator (100) to extend or retract. The cross-sectional area of ​​the piston rod of the actuator (100) is 1 / n of the cross-sectional area of ​​the rodless chamber of the actuator, where n is a positive number greater than 1; The control valve group (3) includes a cartridge valve (31), a first hydraulic directional valve (32), and a pressure control unit (34). The first port of the cartridge valve (31) is connected to the inlet port of the first hydraulic directional valve (32), and the second port of the cartridge valve (31) is connected to the second working port of the directional valve (2). The area of ​​the control port of the cartridge valve (31) is m times the area of ​​the second port of the cartridge valve (31), where m is a positive number not less than 1. The first working port of the first hydraulic directional valve (32) is connected to the rod chamber of the actuator cylinder (100), and the second working port of the first hydraulic directional valve (32) is connected to the rodless chamber of the actuator cylinder (100). The return port of the first hydraulic directional valve (32) is connected to the oil tank. The pressure control unit (34) is connected to the outlet port of the pump group (1), the oil tank, and the control port of the cartridge valve (31). The pressure control unit (34) is used to control the actual output oil pressure of the pump group (1) to be the sum of the theoretical output oil pressure of the pump group (1) and the seawater pressure when the actuator cylinder (100) extends, and to make the control port of the cartridge valve (31) connected to the oil tank. Alternatively, the pressure control unit (34) is used to control the oil pressure at the control port of the cartridge valve (31) to be 1 / nm of the seawater pressure when the actuator cylinder (100) retracts.

2. The hydraulic control system of claim 1, wherein, The pressure control unit (34) includes a pressure regulating device (341), a second hydraulic directional valve (342), a flexible container (343), and an overflow valve (345). The first oil port of the pressure regulating device (341) is connected to the control oil port of the cartridge valve (31), the second oil port of the pressure regulating device (341) is connected to the first working oil port of the second hydraulic directional valve (342), the control oil port of the second hydraulic directional valve (342) is connected to the second working oil port of the directional valve (2), the oil inlet of the second hydraulic directional valve (342) is connected to the flexible container (343), and the oil return port of the second hydraulic directional valve (342) is connected to the oil tank. The oil inlet of the overflow valve (345) is connected to the oil outlet of the pump group (1) and the oil inlet of the reversing valve (2), respectively. The oil return port of the overflow valve (345) is connected to the oil tank. The control port of the overflow valve (345) is connected to the second working port of the second hydraulic reversing valve (342). The flexible container (343) contains oil, and the flexible container (343) can deform under water pressure so that the oil inside flows out under water pressure.

3. The hydraulic control system of claim 2, wherein, The flexible container (343) is one of a rubber bladder or a leather bladder.

4. The hydraulic control system of claim 2, wherein, The pressure regulating device (341) is one of the following: pressure reducing valve, oil cylinder, or throttle pipe.

5. The hydraulic control system of claim 1, wherein, The hydraulic control system also includes a hydraulic lock (5), which includes a first hydraulic check valve (51) and a second hydraulic check valve (52). The oil inlet of the first hydraulic check valve (51) is connected to the first working oil port of the reversing valve (2) and the first working oil port of the first hydraulic reversing valve (32), respectively. The oil outlet of the first hydraulic check valve (51) is connected to the rod chamber of the actuator cylinder (100). The control oil port of the first hydraulic check valve (51) is connected to the oil inlet of the second hydraulic check valve (52). The inlet of the second hydraulic check valve (52) is connected to the second port of the cartridge valve (31) and the second working port of the first hydraulic directional valve (32), respectively. The outlet of the second hydraulic check valve (52) is connected to the rodless chamber of the actuator cylinder (100), and the control port of the second hydraulic check valve (52) is connected to the inlet of the first hydraulic check valve (51).

6. The hydraulic control system of claim 5, wherein, The hydraulic control system further includes a first check valve (6), which is connected between the directional valve (2) and the hydraulic lock (5). The oil inlet of the first check valve (6) is connected to the first working oil port of the directional valve (2), and the oil outlet of the first check valve (6) is connected to the oil inlet of the first hydraulic control check valve (51).

7. The hydraulic control system of claim 5, wherein, The hydraulic control system further includes a second check valve (7), which is connected between the directional valve (2) and the cartridge valve (31). The inlet of the second check valve (7) is connected to the second working port of the directional valve, and the outlet of the second check valve (7) is connected to the second port of the cartridge valve (31).

8. The hydraulic control system of claim 7, wherein, The hydraulic control system further includes a third check valve (8), which is connected between the second hydraulic check valve (52) and the cartridge valve (31). The inlet of the third check valve (8) is connected to the outlet of the second hydraulic check valve (52), and the outlet of the third check valve (8) is connected to the second port of the cartridge valve (31) and the outlet of the second check valve (7).

9. The hydraulic control system of any one of claims 1-8, wherein, The reversing valve (2) is a three-position four-way electromagnetic proportional reversing valve.

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