A method for overload protection of a hydraulic circuit

Abstract

The present application provides a kind of overload protection method of hydraulic oil circuit, records throttle valve at different opening, the full load oil pressure value of winch system full load operation;Thus at the current full load oil pressure value, the oil pressure value of more than 1.1 times overload can be calculated, and the calculation is accurate;Throttle valve amplification inlet pipeline in the oil pump and multi-way valve group area oil pressure, so that the increase between full load oil pressure value and overload oil pressure value, and then pressure switch can accurately detect the numerical difference between full load oil pressure value and overload oil pressure value;So pressure switch can accurately detect whether winch system has overload.

Description

Technical Field

[0001] This invention relates to the field of crane winch technology, and more specifically to an overload protection method for hydraulic circuits. Background Technology

[0002] Offshore cranes are one of the main pieces of equipment on offshore platforms, primarily used for lifting equipment and transporting personnel. Due to the complex marine climate and environment, the working conditions for cranes are harsh, requiring high safety performance. Cranes are equipped with multiple safety protection functions, ensuring that serious overloading will not occur under normal circumstances. However, if the crane is overloaded, depressurization is necessary.

[0003] For example, Chinese patent application number 202122954349.7, published on June 7, 2022, discloses an overload protection hydraulic system for a winch, including an oil tank, an output valve group, an overload valve group, and a regulating valve group. The regulating valve group includes a hydraulically controlled directional valve and a regulating shuttle valve. The P end of the hydraulically controlled directional valve is connected to a multi-way valve via a three-way valve, and the control port of the hydraulically controlled directional valve is connected to one end of the regulating shuttle valve. The A end of the hydraulically controlled directional valve is connected to the output valve group, the T end of the hydraulically controlled directional valve is connected to the oil tank, and the B end of the hydraulically controlled directional valve is normally closed. The overload valve group includes an overload sequence valve, one end of which is connected to the output valve group, and the other end of which is connected to the third end of the regulating shuttle valve.

[0004] The hydraulic system detects pressure through a sequence valve. In its overload protection method, for small-tonnage cranes, the pressure value under full load is not significantly different from the pressure value under 1.1 times overload. Therefore, the sequence valve cannot accurately identify whether the crane is overloaded, and thus cannot provide a reliable overload protection method. Summary of the Invention

[0005] This invention provides an overload protection method for hydraulic circuits. By amplifying the pressure difference between the full-load oil pressure value and the overload oil pressure value, it can accurately detect whether the winch system is overloaded. When overloaded, the hydraulic circuit is depressurized, which can reliably achieve overload protection.

[0006] To achieve the above objectives, the technical solution of the present invention is: an overload protection method for a hydraulic circuit, comprising the following steps:

[0007] S1. The three-position seven-way manual control directional valve is switched to the left position. The hydraulic oil output by the oil pump is input into port B of the three-position seven-way manual control directional valve through the oil inlet pipeline. A part of the hydraulic oil flows to port E, and then flows from port F to port C through the winch system, and then flows into the return oil pipeline to drive the winch in the winch system to lift.

[0008] S2. Another portion of the hydraulic oil flowing out from port B flows to port D, and through shuttle valve one and shuttle valve two, flows to the control end of the pilot-operated relief valve, controlling the input and output ends of the pilot-operated relief valve to be cut off.

[0009] S3. Adjust the throttle valve to reduce the oil volume between the oil pump and the multi-way valve group, and amplify the oil pressure in the oil inlet pipeline in the area between the oil pump and the multi-way valve group; the pressure switch records the full-load oil pressure value of the winch system when the throttle valve is at different opening degrees.

[0010] S4. The pressure switch continuously checks the amplified oil pressure value. If the current oil pressure value is more than 1.1 times the full-load oil pressure value at a certain opening of the throttle valve, then proceed to S5.

[0011] S5. The pressure switch sends a signal to the two-position two-way solenoid ball valve one, and the two-position two-way solenoid ball valve one switches to open.

[0012] S6. The hydraulic oil flowing from port D of the three-position seven-way manual control directional valve flows to the two-position two-way solenoid ball valve and then enters the return pipeline, and does not affect the control end of the pilot-operated relief valve.

[0013] S7. The input and output ends of the pilot-operated relief valve are connected. The hydraulic oil output from the oil pump enters the return oil line through the pilot-operated relief valve to relieve pressure on the multi-way valve group.

[0014] S8. If the winch system needs to move in another direction, then proceed to S9.

[0015] S9. The three-position seven-way manual control directional valve is switched to the right position. The hydraulic oil output by the oil pump is input into port B of the three-position seven-way manual control directional valve through the oil inlet pipeline. A part of the hydraulic oil flows to port F, and then flows from port E to port A through the winch system, and then flows into the return oil pipeline to drive the winch in the winch system to descend.

[0016] The above method records the full-load oil pressure values ​​of the winch system under different throttle valve openings. This allows for the calculation of oil pressure values ​​exceeding 1.1 times the overload value under the current full-load oil pressure, ensuring accuracy. The throttle valve amplifies the oil pressure in the oil pump and multi-way valve assembly area of ​​the inlet pipeline, increasing the difference between the full-load and overload oil pressure values. Consequently, the pressure switch can accurately detect the numerical difference between the full-load and overload oil pressure values, thus enabling accurate detection of whether the winch system is overloaded.

[0017] Furthermore, this is achieved through a winch overload protection oil circuit, which includes an oil tank, a multi-way valve group, and a winch system. The oil tank is connected to an inlet oil line and a return oil line. An oil pump is installed in the inlet oil line. The input end of the oil pump is connected to the oil tank, and the output end of the oil pump is connected to the multi-way valve group. The multi-way valve group is also connected to the winch system and the return oil line. A pressure switch and a throttle valve are connected between the output end of the oil pump and the multi-way valve group. The throttle valve is used to increase the oil pressure in the oil circuit between the oil pump and the multi-way valve group, and the pressure switch is used to detect the pressure value in the oil circuit between the oil pump and the multi-way valve group.

[0018] The multi-way valve assembly includes a three-position seven-way manually controlled directional valve, a two-position two-way solenoid ball valve I, a two-position two-way solenoid ball valve II, a shuttle valve I, a shuttle valve II, and a pilot-operated relief valve; the two-position two-way solenoid ball valve I and the two-position two-way solenoid ball valve II are connected to the pressure switch signal.

[0019] The three-position seven-way manually controlled directional valve includes ports A, B, C, D, E, F, and G. The output of the oil pump is connected to port B and the input of the pilot-operated relief valve. Ports A and C are both connected to the return oil line. Port D is connected to the first input of shuttle valve one. The output of shuttle valve one is connected to the second input of shuttle valve two. The output of shuttle valve two is connected to the control terminal of the pilot-operated relief valve.

[0020] The first input terminal of shuttle valve one is also connected to the input terminal of two-position two-way solenoid ball valve one. The output terminal of two-position two-way solenoid ball valve one and the output terminal of pilot-operated relief valve are both connected to the return oil line. Port E is connected to one end of the winch system. Port F is connected to the other end of the winch system. Port G is connected to the second input terminal of shuttle valve one. The second input terminal of shuttle valve one is also connected to the input terminal of two-position two-way solenoid ball valve two. The output terminal of two-position two-way solenoid ball valve two is connected to the return oil line.

[0021] The above oil circuit, controlled by a three-position seven-way manual directional control valve, drives the winch system. When the winch system is under normal load, the oil circuit of the two-position two-way solenoid ball valve is closed, and the hydraulic oil flowing from port D of the three-position seven-way manual directional control valve flows through shuttle valve one and shuttle valve two to the control end of the pilot-operated relief valve, cutting off the connection between the input and output ends of the pilot-operated relief valve. When the winch system is overloaded, the pressure switch sends a signal to the two-position two-way solenoid ball valve, which then switches to open, allowing the hydraulic oil flowing from port D of the three-position seven-way manual directional control valve to resume operation. The oil flows to the 2-position 2-way solenoid ball valve and then into the return line. The hydraulic oil flowing out from port D does not pass through shuttle valve 1, so there is no oil pressure at the control end of the pilot-operated relief valve. The pilot-operated relief valve opens, and the input and output ends of the pilot-operated relief valve are connected. The hydraulic oil output from the oil pump enters the return line through the pilot-operated relief valve, which relieves pressure on the multi-way valve group. This prevents the winch system from lifting when overloaded, thus avoiding potential safety hazards during overload lifting and ensuring the safety of the winch system during operation.

[0022] The throttle valve is set to reduce the flow rate of hydraulic oil input to the multi-way valve group, and the oil pressure in the oil pump and multi-way valve group area of ​​the oil inlet line is amplified, so that the oil pressure value of the hydraulic oil passing through the pressure switch is increased; thus, the difference between the oil pressure value when the winch system is fully loaded and the oil pressure value when it is overloaded by 1.1 times is increased, so that the pressure switch can accurately detect whether the winch system is overloaded.

[0023] Furthermore, the winch system includes a hoisting motor and a hoisting balance valve. The hoisting balance valve includes a hoisting check valve and a hoisting relief valve. The output end of the hoisting relief valve is connected to port F, the input end of the hoisting relief valve is connected to one end of the hoisting motor, the other end of the hoisting motor and the control end of the hoisting relief valve are connected to port E, the input end of the hoisting check valve is connected to the output end of the hoisting relief valve, and the output end of the hoisting check valve is connected to the input end of the hoisting relief valve.

[0024] In the above oil circuit, when the three-position seven-way manual control directional valve is switched to the left position, the hydraulic oil flows from port B to port E, and then flows to the control end of the lifting relief valve. After the lifting relief valve is turned on, the oil flows to the lifting motor, and then flows through the lifting relief valve into the three-position seven-way manual control directional valve, from port F to port C, and then flows into the return oil line and enters the oil tank, thereby realizing the lifting motor driving the winch to move in one direction.

[0025] When the three-position seven-way manual control directional valve is switched to the right position, the hydraulic oil flows from port B to port F, then flows through the hoisting check valve and into one end of the hoisting motor, then flows from the other end of the hoisting motor into the three-position seven-way manual control directional valve, from port E to port A, and then flows into the return oil line and into the oil tank, thereby enabling the hoisting motor to drive the winch to move in the other direction.

[0026] The winch is raised and lowered by driving the hoisting motor to move in different directions.

[0027] Furthermore, the winch system also includes a normally closed brake and a lifting shuttle valve. The first input end of the lifting shuttle valve is connected to port F, the second input end of the lifting shuttle valve is connected to port E, and the output end of the lifting shuttle valve is connected to the cylinder of the normally closed brake. The normally closed brake acts on the output shaft of the lifting motor.

[0028] The above hydraulic circuit brakes the hoisting motor via a normally closed brake. When the hoisting motor needs to be driven, a portion of the hydraulic oil output from port F or E of the three-position seven-way manual control directional valve flows into the hoisting shuttle valve, and then flows into the normally closed brake, releasing the output shaft of the hoisting motor from the normally closed brake, ensuring high reliability. When the three-position seven-way manual control directional valve resets to the neutral position, the hydraulic oil input stops; the hydraulic oil flows back from the cylinder of the normally closed brake to the three-position seven-way manual control directional valve.

[0029] Furthermore, in S1, the hoisting of the winch in the drive winch system is specifically as follows: hydraulic oil flows from port B to port E. A portion of the hydraulic oil flows into the hoisting shuttle valve, and then from the hoisting shuttle valve into the normally closed brake, releasing the normally closed brake from the output shaft of the hoisting motor. The other portion flows to the control end of the hoisting relief valve, which, after opening the hoisting relief valve, flows to the hoisting motor, and then through the hoisting relief valve into the three-position seven-way manual control directional valve, flowing from port F to port C, and then into the return oil line and finally into the oil tank, thus realizing the hoisting motor driving the winch to hoist. This method is simple.

[0030] Furthermore, in S9, the descent of the winch in the drive winch system is specifically as follows: hydraulic oil flows from port B to port F. A portion of the hydraulic oil flows into the lifting shuttle valve, and then from the lifting shuttle valve into the normally closed brake, releasing the normally closed brake from the output shaft of the lifting motor. The other portion flows through the lifting check valve and into one end of the lifting motor, then from the other end of the lifting motor into the three-position seven-way manual control directional valve, flowing from port E to port A, and then into the return oil line and into the oil tank, thus enabling the lifting motor to drive the winch to move in the opposite direction. This method is simple. Attached Figure Description

[0031] Figure 1 The schematic diagram of the winch overload protection oil circuit of the present invention.

[0032] Figure 2 for Figure 1 Enlarged view of the middle W section.

[0033] Figure 3 A schematic diagram of each interface of the three-position seven-way manual-electric control directional valve in the winch overload protection oil circuit of this invention.

[0034] Figure 4 The hydraulic schematic diagram of the winch system invented to realize the winch overload protection oil circuit of the present invention.

[0035] Figure 5 This is a flowchart of the present invention. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1-5 As shown, an overload protection method for a hydraulic circuit includes an oil tank 1, a multi-way valve group 2, a winch system 3, a pressure switch 4, and a throttle valve 5. The oil tank 1 is connected to an inlet pipe 11 and a return pipe 12. An oil pump 13 is installed in the inlet pipe 11. The input end of the oil pump 13 is connected to the oil tank 1, and the output end of the oil pump 13 is connected to the multi-way valve group 2. The multi-way valve group 2 is also connected to the winch system 3 and the return pipe 12. The pressure switch 4 and the throttle valve 5 are connected between the output end of the oil pump 13 and the multi-way valve group 2. The throttle valve 5 is used to amplify the oil pressure in the oil circuit between the oil pump 13 and the multi-way valve group 2, and the pressure switch 4 is used to detect the pressure value in the oil circuit between the oil pump 13 and the multi-way valve group 2.

[0038] The multi-way valve group 2 includes a three-position seven-way manually controlled directional valve 21, a two-position two-way solenoid ball valve 22, a two-position two-way solenoid ball valve 23, a shuttle valve 24, a shuttle valve 25, and a pilot-operated relief valve 26; the two-position two-way solenoid ball valve 22 and the two-position two-way solenoid ball valve 23 are connected to the pressure switch 4 for signal connection.

[0039] The three-position seven-way manual control directional valve 21 includes ports A, B, C, D, E, F, and G. The output end of the oil pump 13 is connected to port B and the input end of the pilot-operated relief valve 26. Ports A and C are both connected to the return oil line 12. Port D is connected to the first input end of shuttle valve 1 24. The output end of shuttle valve 1 24 is connected to the second input end of shuttle valve 25. The output end of shuttle valve 25 is connected to the control end of the pilot-operated relief valve 26.

[0040] The first input terminal of shuttle valve 24 is also connected to the input terminal of two-position two-way solenoid ball valve 22. The output terminals of two-position two-way solenoid ball valve 22 and pilot-operated relief valve 26 are both connected to return oil line 12. Port E is connected to one end of winch system 3. Port F is connected to the other end of winch system 3. Port G is connected to the second input terminal of shuttle valve 24. The second input terminal of shuttle valve 24 is also connected to the input terminal of two-position two-way solenoid ball valve 23. The output terminal of two-position two-way solenoid ball valve 23 is connected to return oil line 12.

[0041] The throttle valve 5 reduces the hydraulic oil flow rate into the multi-way valve group 2, amplifies the oil pressure in the oil pump 13 and multi-way valve group 2 area of ​​the oil inlet pipe 11, and increases the oil pressure value of the hydraulic oil passing through the pressure switch 4. This increases the difference between the oil pressure value of the winch system 3 when it is fully loaded and the oil pressure value when it is overloaded by 1.1 times, so that the pressure switch 4 can accurately detect whether the winch system 3 is overloaded.

[0042] In this embodiment, a hydraulically controlled check valve 27 is provided between the output end of the oil pump 13 and the three-position seven-way manually controlled directional valve 21. The input end of the hydraulically controlled check valve 27 is connected to the output end of the oil pump 13, the output end of the hydraulically controlled check valve 27 is connected to port B of the three-position seven-way manually controlled directional valve 21, and the control end of the hydraulically controlled check valve 27 is connected to the right input end of the shuttle valve 25. The hydraulically controlled check valve 27 protects the three-position seven-way manually controlled directional valve 21, preventing high-pressure hydraulic oil from directly impacting it, and also balances the pressure between the output end of the oil pump 13 and the inlet end of the three-position seven-way manually controlled directional valve 21.

[0043] A first relief valve 28 is provided between the first input end of shuttle valve 24 and the return oil line 12, and between the second input end and the return oil line 12. The first relief valve 28 is provided to control the pressure of the hydraulic oil flowing through shuttle valve 24.

[0044] A pressure gauge 19 is installed at the input end of the pilot-operated relief valve 26 via a quick-connect fitting 291 with a check valve. This installation of the pressure gauge 29 via the quick-connect fitting 291 with a check valve ensures that the oil circuit is blocked with the check valve before replacing or removing the pressure gauge, preventing leakage and enabling quick replacement. The pressure gauge 29 can visually display the oil pressure in the oil circuit.

[0045] The winch system 3 includes a hoisting motor 31 and a hoisting balance valve 32. The hoisting balance valve 32 includes a hoisting check valve 321 and a hoisting relief valve 322. The output end of the hoisting relief valve 322 is connected to port F, and the input end of the hoisting relief valve 322 is connected to one end of the hoisting motor 31. The other end of the hoisting motor 31 and the control end of the hoisting relief valve 322 are connected to port E. The input end of the hoisting check valve 321 is connected to the output end of the hoisting relief valve 322, and the output end of the hoisting check valve 321 is connected to the input end of the hoisting relief valve 322. The hoisting motor 31 drives the winch to move in different directions, realizing the hoisting and lowering of the winch.

[0046] When the three-position seven-way manual control directional valve 21 is switched to the left, the hydraulic oil flows from port B to port E, and then to the control end of the lifting relief valve 322. After the lifting relief valve 322 is turned on, the oil flows to the lifting motor 31, and then flows through the lifting relief valve 322 into the three-position seven-way manual control directional valve 21, from port F to port C, and then into the return oil line 12 and into the oil tank 1, thereby enabling the lifting motor 31 to drive the winch to move in one direction.

[0047] When the three-position seven-way manual control directional valve 21 is switched to the right position, the hydraulic oil flows from port B to port F, then flows through the hoisting check valve 321 and into one end of the hoisting motor 31, then flows from the other end of the hoisting motor 31 into the three-position seven-way manual control directional valve 21, from port E to port A, and then flows into the return oil line 12 and into the oil tank 1, thereby enabling the hoisting motor 31 to drive the winch to move in the other direction.

[0048] The winch system 3 also includes a normally closed brake 33 and a lifting shuttle valve 34. The first input end of the lifting shuttle valve 34 is connected to port F, the second input end of the lifting shuttle valve 34 is connected to port E, and the output end of the lifting shuttle valve 34 is connected to the cylinder of the normally closed brake 33. The normally closed brake 33 acts on the output shaft of the lifting motor 31. The lifting motor 31 is braked by the normally closed brake 33. When the lifting motor 31 needs to be driven, a portion of the hydraulic oil output from port F or port E of the three-position seven-way manual control directional valve 21 flows into the lifting shuttle valve 34, and then flows into the normally closed brake 33, so that the normally closed brake 33 releases the brake on the output shaft of the lifting motor 31, which has good reliability. When the three-position seven-way manual control directional valve 21 is reset to the neutral position, the hydraulic oil input stops; the hydraulic oil flows back from the cylinder of the normally closed brake 33 to the three-position seven-way manual control directional valve 21.

[0049] When the winch system 3 is overloaded, the hydraulic oil output from the oil pump 13 enters the return oil line 12 through the pilot-operated relief valve 26 to depressurize the multi-way valve group 2, so that the winch system 3 cannot lift when overloaded, and thus will not lift when overloaded, thereby avoiding potential safety hazards when lifting under overload conditions; ensuring the safety of the winch system 3 during operation.

[0050] In this implementation, when the throttle valve is fully open, if the full-load oil pressure is 4 MPa, the overload oil pressure in the area of ​​oil pump 13 and multi-way valve group 2 is above 4.4 MPa. It is necessary to detect an oil pressure above 4.4 MPa to determine that the winch system is overloaded. However, when the winch system is overloaded by 1.1 times, the overload oil pressure is 4.4 MPa. The overload oil pressure of 4.4 MPa is close to the full-load oil pressure of 4 MPa, so it is not possible to accurately detect whether the winch system is overloaded. By reducing the opening of the throttle valve, the flow rate of hydraulic oil is reduced, and the oil pressure of hydraulic oil is amplified. If the full-load oil pressure is 10 MPa, then the overload oil pressure in the area of ​​oil pump 13 and multi-way valve group 2 is above 11 MPa. It is necessary to detect an oil pressure of above 11 MPa to determine that the winch system is overloaded. When the winch system is overloaded by 1.1 times, the overload oil pressure is 11 MPa. The difference between the overload oil pressure of 11 MPa and the full-load oil pressure of 10 MPa is relatively large, which is sufficient to accurately detect whether the winch system is overloaded.

[0051] like Figure 5 As shown, the overload protection method for hydraulic circuits includes the following steps:

[0052] S1. The three-position seven-way manual control directional valve is switched to the left position. The hydraulic oil output by the oil pump is input into port B of the three-position seven-way manual control directional valve through the oil inlet pipeline. A part of the hydraulic oil flows to port E, and then flows from port F to port C through the winch system, and then flows into the return oil pipeline to drive the winch in the winch system to lift.

[0053] S2. Another portion of the hydraulic oil flowing out from port B flows to port D, and through shuttle valve one and shuttle valve two, flows to the control end of the pilot-operated relief valve, controlling the input and output ends of the pilot-operated relief valve to be cut off.

[0054] S3. Adjust the throttle valve to reduce the oil volume between the oil pump and the multi-way valve group, and amplify the oil pressure in the oil inlet pipeline in the area between the oil pump and the multi-way valve group; the pressure switch records the full-load oil pressure value of the winch system when the throttle valve is at different opening degrees.

[0055] S4. The pressure switch continuously checks the amplified oil pressure value. If the current oil pressure value is more than 1.1 times the full-load oil pressure value at a certain opening of the throttle valve, then proceed to S5.

[0056] S5. The pressure switch sends a signal to the two-position two-way solenoid ball valve one, and the two-position two-way solenoid ball valve one switches to open.

[0057] S6. The hydraulic oil flowing from port D of the three-position seven-way manual control directional valve flows to the two-position two-way solenoid ball valve and then enters the return pipeline, and does not affect the control end of the pilot-operated relief valve.

[0058] S7. The input and output ends of the pilot-operated relief valve are connected. The hydraulic oil output from the oil pump enters the return oil line through the pilot-operated relief valve to relieve pressure on the multi-way valve group.

[0059] S8. If the winch system needs to move in another direction, then proceed to S9.

[0060] S9. The three-position seven-way manual control directional valve is switched to the right position. The hydraulic oil output by the oil pump is input into port B of the three-position seven-way manual control directional valve through the oil inlet pipeline. A part of the hydraulic oil flows to port F, and then flows from port E to port A through the winch system, and then flows into the return oil pipeline to drive the winch in the winch system to descend.

[0061] The above method records the full-load oil pressure values ​​of the winch system under different throttle valve openings. This allows for the calculation of oil pressure values ​​exceeding 1.1 times the overload value under the current full-load oil pressure, ensuring accuracy. The throttle valve amplifies the oil pressure in the oil pump and multi-way valve assembly area of ​​the inlet pipeline, increasing the difference between the full-load and overload oil pressure values. Consequently, the pressure switch can accurately detect the numerical difference between the full-load and overload oil pressure values, thus enabling accurate detection of whether the winch system is overloaded.

[0062] In the above method,

[0063] In S1, the winch hoisting in the drive winch system is specifically as follows: hydraulic oil flows from port B to port E. A portion of the hydraulic oil flows into the hoisting shuttle valve, and then from the hoisting shuttle valve into the normally closed brake, releasing the normally closed brake from the output shaft of the hoisting motor. The other portion flows to the control end of the hoisting relief valve, which, after opening the hoisting relief valve, flows to the hoisting motor, and then through the hoisting relief valve into the three-position seven-way manual control directional valve, flowing from port F to port C, and then into the return oil line and finally into the oil tank, thus enabling the hoisting motor to drive the winch to hoist. This method is simple.

[0064] In S9, the winch in the drive winch system descends as follows: hydraulic oil flows from port B to port F. A portion of the hydraulic oil flows into the lifting shuttle valve, then into the normally closed brake, releasing the output shaft of the lifting motor. The remaining portion flows through the lifting check valve to one end of the lifting motor, then from the other end into the three-position seven-way manual control directional valve, flowing from port E to port A, and then into the return oil line and finally into the oil tank, thus enabling the lifting motor to drive the winch in the opposite direction. This method is simple.

Claims

1. An overload protection method for a hydraulic circuit, characterized in that: This is achieved through a winch overload protection oil circuit, which includes an oil tank, a multi-way valve group, and a winch system. The oil tank is connected to an inlet oil line and a return oil line. An oil pump is installed in the inlet oil line. The input end of the oil pump is connected to the oil tank, and the output end of the oil pump is connected to the multi-way valve group. The multi-way valve group is also connected to the winch system and the return oil line. A pressure switch and a throttle valve are connected between the output end of the oil pump and the multi-way valve group. The throttle valve is used to increase the oil pressure in the oil circuit between the oil pump and the multi-way valve group, and the pressure switch is used to detect the pressure value in the oil circuit between the oil pump and the multi-way valve group. The multi-way valve assembly includes a three-position seven-way manually controlled directional valve, a two-position two-way solenoid ball valve I, a two-position two-way solenoid ball valve II, a shuttle valve I, a shuttle valve II, and a pilot-operated relief valve; the two-position two-way solenoid ball valve I and the two-position two-way solenoid ball valve II are connected to the pressure switch signal. The three-position seven-way manual control directional valve includes ports A, B, C, D, E, F, and G. The output end of the oil pump is connected to port B and the input end of the pilot-operated relief valve. Ports A and C are both connected to the return oil line. Port D is connected to the first input end of shuttle valve one. The output end of shuttle valve one is connected to the second input end of shuttle valve two. The output end of shuttle valve two is connected to the control end of the pilot-operated relief valve. The first input terminal of shuttle valve one is also connected to the input terminal of two-position two-way solenoid ball valve one. The output terminals of two-position two-way solenoid ball valve one and the pilot-operated relief valve are both connected to the return oil line. Port E is connected to one end of the winch system; Port F is connected to the other end of the winch system; Port G is connected to the second input terminal of shuttle valve one, and the second input terminal of shuttle valve one is also connected to the input terminal of two-position two-way solenoid ball valve two. The output terminal of two-position two-way solenoid ball valve two is connected to the return oil line. The process includes the following steps: S1. The three-position seven-way manual control directional valve is switched to the left position. The hydraulic oil output by the oil pump is input into port B of the three-position seven-way manual control directional valve through the oil inlet pipeline. A part of the hydraulic oil flows to port E, and then flows from port F to port C through the winch system, and then flows into the return oil pipeline to drive the winch in the winch system to lift. S2. Another portion of the hydraulic oil flowing out from port B flows to port D, and through shuttle valve one and shuttle valve two flows to the control end of the pilot-operated relief valve, controlling the input and output ends of the pilot-operated relief valve to be cut off. S3. Adjust the throttle valve to reduce the oil volume between the oil pump and the multi-way valve group, and amplify the oil pressure in the oil inlet pipeline in the area between the oil pump and the multi-way valve group; the pressure switch records the full-load oil pressure value of the winch system when the throttle valve is at different opening degrees. S4. The pressure switch continuously checks the amplified oil pressure value. If the current oil pressure value is more than 1.1 times the full-load oil pressure value at a certain opening of the throttle valve, then proceed to S5. S5. The pressure switch sends a signal to the two-position two-way solenoid ball valve one, and the two-position two-way solenoid ball valve one switches to open. S6. The hydraulic oil flowing out of port D of the three-position seven-way manual control directional valve flows to the two-position two-way solenoid ball valve and then enters the return pipeline, and does not affect the control end of the pilot-operated relief valve. S7. The input and output ends of the pilot-operated relief valve are connected, and the hydraulic oil output from the oil pump enters the return oil line through the pilot-operated relief valve to relieve pressure on the multi-way valve group. S8. If the winch system needs to move in another direction, then proceed to S9. S9. The three-position seven-way manual control directional valve is switched to the right position. The hydraulic oil output by the oil pump is input into port B of the three-position seven-way manual control directional valve through the oil inlet pipeline. A part of the hydraulic oil flows to port F, and then flows from port E to port A through the winch system, and then flows into the return oil pipeline to drive the winch in the winch system to descend.

2. The overload protection method for a hydraulic circuit according to claim 1, characterized in that: The winch system includes a hoisting motor and a hoisting balance valve. The hoisting balance valve includes a hoisting check valve and a hoisting relief valve. The output end of the hoisting relief valve is connected to port F, the input end of the hoisting relief valve is connected to one end of the hoisting motor, the other end of the hoisting motor and the control end of the hoisting relief valve are connected to port E, the input end of the hoisting check valve is connected to the output end of the hoisting relief valve, and the output end of the hoisting check valve is connected to the input end of the hoisting relief valve.

3. The method for overload protection of a hydraulic circuit according to claim 2, characterized in that: The winch system also includes a normally closed brake and a lifting shuttle valve. The first input end of the lifting shuttle valve is connected to port F, the second input end of the lifting shuttle valve is connected to port E, and the output end of the lifting shuttle valve is connected to the cylinder of the normally closed brake. The normally closed brake acts on the output shaft of the lifting motor.

4. The overload protection method for a hydraulic circuit according to claim 3, characterized in that: In S1, the winch hoisting in the drive winch system is specifically as follows: hydraulic oil flows from port B to port E. Part of the hydraulic oil flows into the hoisting shuttle valve, and then from the hoisting shuttle valve into the normally closed brake, causing the normally closed brake to release the output shaft of the hoisting motor. The other part flows to the control end of the hoisting relief valve, and after the hoisting relief valve is opened, it flows to the hoisting motor, and then through the hoisting relief valve into the three-position seven-way manual electric control directional valve, flowing from port F to port C, and then into the return oil line and into the oil tank, thereby realizing the hoisting motor driving the winch to hoist.

5. The overload protection method for a hydraulic circuit according to claim 3, characterized in that: In S9, the winch in the drive winch system descends as follows: hydraulic oil flows from port B to port F. Part of the hydraulic oil flows into the lifting shuttle valve, and then from the lifting shuttle valve into the normally closed brake, releasing the normally closed brake from the output shaft of the lifting motor. The other part flows through the lifting check valve and into one end of the lifting motor, and then from the other end of the lifting motor into the three-position seven-way manual electric control directional valve, flowing from port E to port A, and then into the return oil line and into the oil tank, thereby enabling the lifting motor to drive the winch to move in the other direction.

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