A hoist hydraulic system based on torque balance and a crane

Abstract

This invention discloses a hoisting hydraulic system and crane based on torque balance. The system includes an accumulator pressure replenishment system, comprising a hydraulically controlled check valve, an accumulator, a two-position two-way solenoid directional valve, a force limiter, and a pressure sensor. The outlet of the hydraulically controlled check valve is connected to the accumulator, and the inlet of the hydraulically controlled check valve is connected to the oil passage in the motor starting port cavity between the motor starting port B and the hoisting balance valve. The pressure sensor is connected to the pilot handle and the force limiter, respectively, and is used to collect the pressure of the pilot handle and send it to the force limiter. The force limiter is connected to the solenoid coil of the two-position two-way solenoid directional valve, and the two-position two-way solenoid directional valve is connected to the control port of the hydraulically controlled check valve. This invention can solve problems such as pressure shock and vibration noise that occur during heavy-load start-up of the hoisting mechanism, improve the smoothness of the heavy-load start-up action of the hoisting system, and enhance operational comfort.

Description

Technical Field

[0001] This invention relates to cranes, and more specifically to a winch hydraulic system and crane based on torque balance. Background Technology

[0002] Cranes rely on hydraulic winch systems to drive mechanisms to complete the lifting, loading, and unloading of heavy objects. The hydraulic winch system is the power and control means for the winch mechanism to work, and its performance directly determines the lifting performance level and has a great impact on the reliability and efficiency of crane operation.

[0003] The hydraulic winch mechanism includes a winch hydraulic system, which uses a hydraulic motor to drive the winch drum to wind up and unwind the wire rope. The lifting and lowering of the load is achieved by utilizing the linear displacement of the wire rope. A brake is installed in the winch mechanism, providing static braking and locking functions when the winch is stationary, ensuring the load can be stopped at any position. A balance valve is also included in the winch hydraulic system to provide dynamic braking and load holding functions during winch start-up and stop operations.

[0004] During the operation of crane winches, heavy-load conditions are frequently encountered. When the load is suspended in mid-air and held stationary, the brake plates of the winch reducer bear the load torque applied to the drum by the load through friction. After the brake is closed, the motor, under the action of the lifting pressure, rotates in the opposite direction within the allowable range of the transmission chain clearances (internal clearance of the motor, clearance between the motor output shaft and the spline sleeve, and clearance between the spline sleeve and the friction plate). (Due to the small angle, the motor speed encoder cannot recognize it). The motor's reverse rotation causes the lifting cavity of the motor to expand, resulting in a rapid drop in pressure (in extreme cases, the pressure is below 3 bar). At the moment of restarting the winch (lifting or lowering), when the brake is opened, the load torque is quickly transmitted from the brake to the hydraulic motor lifting cavity. Under the action of the heavy load, the motor establishes a hydraulic torque to support the load by compressing the lifting cavity. Since the balance valve is not open, the winch mechanism has a brief "acceleration-stop" process during this period. Due to the clearances of the mechanism (between the motor and the spline, the spline and the friction plate, and the friction plate and the reducer housing), impacts and elastic deformation of components occur, resulting in vibration and abnormal noise. This impact can be quickly transmitted to the hoisting mechanism and cause vibration. If the mechanism is mounted on a structure with vibration amplification effects, such as a boom, the vibration will be even more pronounced. This vibration reduces the lifespan of hydraulic seals, decreases operator comfort, and in extreme cases, can even lead to safety issues.

[0005] Hydraulic systems for winch mechanisms are divided into open and closed systems. Both systems exhibit impact noise during heavy-load start-up. Industry technicians have addressed this issue effectively by employing pressure memory control logic based on the component characteristics of closed winch systems, which will not be discussed further here. This technical explanation primarily focuses on problems with open winch mechanisms. Extensive research has been conducted within the industry to address the impact noise problem during heavy-load start-up of open winch mechanisms, resulting in numerous solutions.

[0006] Prior art 1 discloses a hoisting mechanism, such as Figure 1 As shown, it mainly consists of a hydraulic oil tank 1, a return oil filter 2, an auxiliary pump 3, a main pump 4, a main pump overflow valve 5, a check valve 6, a shuttle valve 7, a pressure compensation valve 8, a solenoid directional valve 9, a motor drop overflow valve 10, a shuttle valve 11, a hoist balance valve 12, a motor 13, a drum 15, a brake 16, a replenishing oil check valve 17, a brake control valve 18, and a pilot handle 19.

[0007] Prior art 2: Chinese invention patent with publication number CN114933256A discloses a hoist starting control method, device, equipment and crane. The initial starting current value is determined according to the current lifting weight and the preset hook ratio. The pilot proportional control valve is controlled, and the starting compensation current value of the motor is determined according to the motor angle. The current is adjusted to complete the hoist starting work, thereby achieving the smoothness of heavy load starting.

[0008] Prior art 3: Chinese invention patent application with publication number CN203461747U discloses a hoisting hydraulic system for preventing instantaneous shock during startup. It adopts a method of adding a one-way throttle valve to the brake control oil circuit so that the flow rate in the control oil circuit is proportional to the size of the brake cylinder. The purpose is to optimize the relationship between the brake opening and the motor pressure build-up rate, thereby solving the problem of instantaneous shock of the hoisting mechanism during startup.

[0009] However, the aforementioned existing technology has the following shortcomings:

[0010] (1) Regarding the existing technology 1: In the case of heavy-load start-up, due to the poor performance matching of the main valve, balance valve, brake and motor, it is easy to cause large pressure shock during heavy-load start-up, which damages the sealing performance and component reliability of the hydraulic system. In addition, the vibration and abnormal noise caused by the start-up shock seriously affect the health of the operators.

[0011] (2) Regarding the existing technology 2: due to the gap in the transmission chain of the hoisting mechanism, the pressure build-up rate of the motor starting port is slow during heavy-load start-up, which affects the hoisting's heavy-load start-up response.

[0012] (3) Regarding the measures taken by the existing technology 3 to address the impact of heavy-load start-up of the hoisting mechanism, such as setting damping in the brake control oil circuit and delaying the brake opening time, the response time of the hoisting system will be affected. In the case of hoisting falling, there is also the risk of aggravating the brake friction pads. Solutions that rely too much on electronic components and program judgment are not feasible for hydraulic pilot products and cannot solve the problem of abnormal noise from the impact of heavy-load start-up of non-electrically controlled hoists. Summary of the Invention

[0013] Purpose of the invention: The purpose of this invention is to provide a winch hydraulic system and crane based on torque balance, which can solve the problems of pressure shock, vibration and abnormal noise that occur when the winch mechanism starts under heavy load, improve the smoothness of the winch system's heavy load start-up action, and improve the operating comfort.

[0014] Technical solution: The present invention provides a hoisting hydraulic system based on torque balance, including an accumulator pressure replenishment system, wherein the accumulator pressure replenishment system includes a hydraulically controlled check valve, an accumulator, a two-position two-way solenoid directional valve, a force limiter, and a pressure sensor;

[0015] The outlet of the hydraulic control check valve is connected to the accumulator, and the inlet of the hydraulic control check valve is connected to the oil passage of the motor start port cavity between the motor start port B and the winch balance valve.

[0016] The pressure sensor is connected to the pilot handle and the force limiter respectively. The pressure sensor is used to collect the pressure of the pilot handle and send it to the force limiter.

[0017] The force limiter is connected to the solenoid coil of the two-position two-way solenoid directional valve, and the two-position two-way solenoid directional valve is connected to the control port of the hydraulic check valve.

[0018] Furthermore, during the hoisting operation, the oil at the motor's inlet B is used to charge the accumulator via a hydraulic check valve.

[0019] Furthermore, the force limiter collects the pressure signal output by the pilot handle and the single rope tension signal of the winch. When both the pressure signal output by the pilot handle and the single rope tension signal of the winch reach the corresponding preset threshold, the force limiter sends a signal to drive the two-position two-way solenoid directional valve to switch. The pressure oil from the pilot handle drives the hydraulic control check valve to open in both directions. The hydraulic oil in the accumulator is replenished to the motor starting port B through the hydraulic control check valve, thereby pressurizing the accumulator to the motor starting port cavity and realizing the torque balance between the motor starting and ending ports.

[0020] Furthermore, a brake is provided between the motor and the drum, and the opening pressure of the hydraulic check valve is lower than the opening pressure of the brake, so as to replenish the motor opening cavity before the brake is opened.

[0021] Furthermore, the brake is a normally closed brake, and the brake is connected to a brake control valve, which is used to control the opening of the brake.

[0022] Furthermore, the pressure sensor is installed on the output oil passage of the pilot handle to collect the output pressure of the pilot handle and convert the output pressure into a current signal before sending it to the force limiter.

[0023] Furthermore, the two-position two-way solenoid directional valve receives the signal from the force limiter and controls the opening and closing of the pressure replenishment oil circuit according to the received signal.

[0024] Furthermore, it also includes a main pump, and an electromagnetic directional valve is installed on the oil line between the main pump and the motor. The electromagnetic coil at the lower end of the electromagnetic directional valve is connected to the first pressure output port of the pilot handle, and the electromagnetic coil at the upper end of the electromagnetic directional valve is connected to the second pressure output port of the pilot handle.

[0025] Furthermore, a winch balance valve is installed in the oil line between the electromagnetic directional valve and the motor.

[0026] Based on the same inventive concept, the present invention provides a crane including the aforementioned torque balance-based winch hydraulic system.

[0027] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows:

[0028] To effectively suppress or eliminate the problem of abnormal noise and impact during heavy-load start-up of the hoist, specifically, under heavy-load start-up conditions of the hoist mechanism, pressurized oil is added to the motor starting cavity to balance the gravitational torque on the drum caused by the heavy load, so that the motor mechanism and brake start under near torque balance conditions. This avoids the pressure shock and vibration noise caused by the shock under heavy-load start-up conditions in existing technologies, improves the stress condition of the mechanism, and reduces the adverse effects on the sealing performance of the hydraulic system.

[0029] Compared to the slow pressure build-up rate of the motor inlet cavity in existing technologies, which leads to poor heavy-load start-up response, this invention accelerates the pressure build-up speed of the motor inlet cavity and speeds up the system's response speed under heavy-load lifting conditions by supplementing pressure to the motor inlet cavity without changing the system's oil supply flow gradient.

[0030] This invention relies on a force limiter for data processing, and all engineering cranes are equipped with force limiters, resulting in low modification costs and strong applicability. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the hydraulic system of the hoisting mechanism in prior art 1;

[0032] Figure 2 This is a schematic diagram of a hoisting hydraulic system based on torque balance disclosed in an embodiment of the present invention;

[0033] Figure 3 This is a flowchart illustrating the operation of the accumulator pressurization system disclosed in an embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of another hoisting hydraulic system based on torque balance disclosed in an embodiment of the present invention. Detailed Implementation

[0035] The technical solution of the present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0036] Example 1

[0037] like Figure 2 As shown, the present invention discloses a hoisting hydraulic system based on torque balance, specifically involving the following components: a hydraulic oil tank 1, a return oil filter 2, an auxiliary pump 3, a main pump 4, a main pump overflow valve 5, a check valve 6, a first shuttle valve 7, a pressure compensation valve 8, a solenoid directional valve 9, a motor drop-out overflow valve 10, a second shuttle valve 11, a hoisting balance valve 12, a motor 13, a load 14, a drum 15, a brake 16, a replenishing oil check valve 17, a brake control valve 18, a pilot handle 19, a hydraulically controlled check valve 20, an accumulator 21, a two-position two-way solenoid directional valve 22, a force limiter 23, and a pressure sensor 24.

[0038] The main pump 4 provides the power oil source for the motor 13. An electromagnetic directional valve 9 is installed in the oil line between the main pump 4 and the motor 13. By switching the working position of the electromagnetic directional valve 9, the working port of the main pump 4 and the oil port of the motor 13 are switched, thereby changing the rotation direction of the motor 13. To achieve precise control of the motor speed, a pressure compensation valve 8 is installed on the electromagnetic directional valve 9. The electromagnetic coil at the lower end of the electromagnetic directional valve 9 is connected to the first pressure output port of the pilot handle 19, and the electromagnetic coil at the upper end of the electromagnetic directional valve 9 is connected to the second pressure output port of the pilot handle 19. The switching power of the solenoid directional valve 9 comes from the pressure output by the pilot handle 19. The pilot handle 19 has two working pressure output ports 1 and 2 (only one port can output working pressure at a time). The pressure output from port 1 (i.e., the first pressure output port) of the pilot handle 19 acts on the lower end of the solenoid directional valve 9, driving the solenoid directional valve 9 to work in the lower position of the valve core working position (the state of the load rising). The pressure output from port 2 (i.e., the second pressure output port) of the pilot handle 19 acts on the upper end of the solenoid directional valve 9, driving the solenoid directional valve 9 to work in the upper position of the valve core working position (the state of the load falling). If there is no pressure output from either port 1 or 2 of the pilot handle 19, the solenoid directional valve 9 will work in the middle position of the valve core under the action of the return spring. At this time, the oil circuit from the oil pump to the motor is cut off, and the hoisting motion stops. The oil source for the pilot handle 19 comes from the auxiliary pump 3. The hoisting balance valve 12 is located in the oil line between the solenoid directional valve 9 and the motor 13. In actual use, it is directly connected to the motor oil port via bolts (the motor oil port where the balance valve is installed is also referred to as the motor port by professional technicians; for ease of explanation, it will be referred to as motor port B below, and the other motor port as motor port A). When the solenoid directional valve 9 is in the lower position, the pressure oil source from the main pump 4 flows into the motor port B through the check valve inside the hoisting balance valve 12, driving the motor to rotate and lifting the load. When the solenoid directional valve 9 reverses, the pressure oil source from the main pump 4 reaches the motor port A. The pressure oil at the motor port A acts on the control end of the hoisting balance valve 12 through the pipeline, pushing the hoisting balance valve 12 to reverse. The oil returns to the oil tank through the throttling port inside the hoisting balance valve 12, thereby rotating the motor and lowering the load. Brake 16 is located between motor 13 and drum 15. Brake 16 is a normally closed brake and is connected to brake control valve 18, which controls the opening of brake 16. During the operation of the hoisting mechanism, brake 16 plays a decisive role. If brake 16 is not open, drum 15 cannot rotate. As brake 16 is normally closed, the pressure oil from brake control valve 18 acts on the cylinder of brake 16, thereby opening the brake. The switching pressure of brake control valve 18 comes from shuttle valve 7, which extracts the output pressure of pilot handle 19. The input pressure of brake control valve 18 is taken from shuttle valve 11, which extracts the pressure at the motor working port.

[0039] This invention adds an accumulator pressure replenishment system to the traditional lifting hydraulic system. The accumulator pressure replenishment system is used to replenish the pressure in the motor opening cavity between the motor 13 and the winch balance valve 12, so as to achieve motor torque balance and thus suppress or eliminate the impact and abnormal noise problems that occur when the motor is under heavy load.

[0040] The accumulator pressure replenishment system includes a hydraulically controlled check valve 20, an accumulator 21, a two-position two-way solenoid directional valve 22, a force limiter 23, and a pressure sensor 24. The outlet of the hydraulically controlled check valve 20 is connected to the accumulator 21, and the inlet of the hydraulically controlled check valve 20 is connected to the oil passage of the motor inlet cavity between the motor 13 inlet B and the hoisting balance valve 12. The pressure sensor 24 is connected to the pilot handle 19 and the force limiter 23, respectively. The pressure sensor 24 is used to collect the pressure of the pilot handle 19 and send it to the force limiter 23. In this embodiment, the pressure sensor 24 is installed on the output oil passage of the pilot handle 19 to collect the output pressure of the pilot handle 19 and convert the output pressure into a current signal before sending it to the force limiter 23. The force limiter 23 is connected to the solenoid coil of the two-position two-way solenoid directional valve 22, and the two-position two-way solenoid directional valve 22 is connected to the control port of the hydraulically controlled check valve 20. The two-position two-way solenoid directional valve 22 receives the signal from the force limiter 23 and controls the opening and closing of the pressure replenishment oil circuit according to the received signal.

[0041] The accumulator pressurization system is connected to the motor inlet cavity (between motor 13 inlet B and winch balance valve 12) via a hydraulically controlled check valve 20. During winch operation, oil from motor inlet B fills the accumulator 21 through the hydraulically controlled check valve 20. The force limiter 23 collects the pressure signal output from the pilot handle 19 and the winch single-rope tension signal. After program judgment, it sends a signal to the two-position two-way solenoid valve 22 to determine the timing for the accumulator 21 to pressurize the motor inlet cavity. Pressurization of the motor inlet cavity begins when the single-rope tension exceeds X% of the rated tension and the handle output pressure increases from 0 bar to Y bar. Specifically:

[0042] like Figure 2 and Figure 3As shown, the oil at the starting port B of motor 13 fills the accumulator 21 through the hydraulic control check valve 20. The force limiter 23 collects the pressure signal output by the pilot handle 19 and the hoisting single rope tension signal. When both the pressure signal output by the pilot handle 19 and the hoisting single rope tension signal reach the corresponding preset threshold, the force limiter 23 sends a signal to drive the two-position two-way solenoid directional valve 22 to switch. The pressure oil from the pilot handle 19 drives the hydraulic control check valve 20 to open in both directions. The hydraulic oil in the accumulator 21 is replenished to the starting port B of motor 13 through the hydraulic control check valve 20, thereby the accumulator 21 pressurizes the motor starting port cavity and achieves torque balance between the motor starting and ending ports. The single-rope tension signal of the winch is obtained in the following way: 1. Based on the torque balance principle of the crane, the load torque borne by the crane winch hook is calculated according to the collected pressure of the luffing cylinder hydraulic system; 2. Based on the boom length and luffing angle collected by the system, the load lever arm length at the hook is calculated; 3. Based on the load torque and load lever arm values ​​in the first two steps, the load weight borne by the hook is calculated; 4. Based on the hook load weight in the third step, combined with the winch wire rope ratio, the single-rope tension value of the winch is obtained.

[0043] The main working principle of this invention is as follows (taking the lifting, stationary, and falling conditions of a winch carrying a load from the ground as a background):

[0044] Hoisting process (lifting of the load from the ground): The pilot handle 19 outputs pressure at port 1, which acts on the lower end of the solenoid directional valve 9. The solenoid directional valve 9 acts on the lower position of the valve core, and the oil circuit from the main pump 4 to the starting port B of the motor 13 is connected. The oil source discharged from the main pump 4 enters the B port of the motor 13 through the built-in check valve of the hoist balance valve 12. Since the brake 16 is not open, the drum 15 cannot move. The pressure at the starting port B of the motor 13 is gradually built up. The oil at the starting port charges the accumulator 21 through the hydraulic control check valve 20. Since the single rope tension and the pressure signal output by the handle both meet the conditions, the force limiter 23 sends a signal to drive the two-position two-way solenoid valve directional valve 22 to switch (the opening time is set to 50ms, and this value can be adjusted according to the actual situation). The hydraulic control check valve 20 opens in both directions. After 50ms, the hydraulic control check valve 20 closes, and the accumulator 21 maintains pressure. At the same time, the pressure from the output port 1 of the first shuttle valve 7 takes the pressure from the pilot handle 19 to drive the brake control valve 18 to switch. The pressure oil from the motor port B of the second shuttle valve 11 enters the cylinder of the brake 16 after passing through the brake control valve 18, and the brake 16 is opened. When the lifting torque of the motor 13 reaches the load torque of the load, the load begins to lift.

[0045] In the hoisting stationary state: the angle of the pilot handle 19 gradually decreases, and its output working port 1 gradually decreases until it reaches zero. The pressure at the lower end of the solenoid directional valve 9 decreases, and the valve core of the solenoid directional valve 9 gradually returns from the lower position to the middle position under the action of the spring. In the middle position, the oil pump returns oil through the relief valve (the variable pump reduces the discharged oil to a minimum by reducing the displacement), the oil circuit connected to port B of motor 13 is cut off, and there is no power oil flowing in the working chamber of motor 13. Due to the action of the one-way valve inside the hoisting balance valve 12, the motor port B cavity forms the highest system pressure due to the load applied to the drum by the heavy object. As the pressure at motor ports A and B decreases, the brake 16 closes. The brake 16 bears the gravity load torque on the hoist through the friction torque of the friction plate, keeping the load stationary. Within the allowable range of transmission chain clearance (motor internal clearance, motor output shaft and spline sleeve clearance, spline sleeve and friction plate clearance), the motor rotates in the opposite direction (due to the small angle, the motor speed encoder cannot recognize it). The reverse rotation of motor 13 causes the motor inlet cavity to increase, resulting in a rapid drop in pressure (in extreme cases, the pressure is below 3 bar).

[0046] The hoist descending process: After experiencing the hoist's loaded hovering condition, the pressure in the motor inlet cavity is almost zero (there is leakage in the hoist's hydraulic components).

[0047] The output pressure at the working port 2 of the pilot handle 19 gradually increases, acting on the upper end of the solenoid directional valve 9. The solenoid directional valve 19 gradually switches to the upper position of the valve core, and the oil circuit from the main pump 4 to the motor 13 drop port A is opened. The oil source discharged from the main pump 4 enters the motor drop port A. Since the brake 16 and the winch balance valve 12 are not open, the drum 15 cannot move. During this process, the force limiter 23 collects the pressure from the pilot handle 19 sent by the pressure sensor 24, which increases from 0 bar to Y bar. In addition, the single rope pressure signal reaches X% of the rated pressure, which meets the pressure compensation condition preset by the program. The force limiter 23 sends a signal to drive the two-position two-way solenoid directional valve 22 to switch. The pressure oil from the pilot handle 19 drives the hydraulic control check valve 20 to open, and the hydraulic pressure in the accumulator 21 is replenished into the motor starting port cavity. As the opening of the electromagnetic reversing valve 9 increases, pressure gradually builds up at the motor 12's lowering port A. The first shuttle valve 7 takes pressure from the output port 2 of the pilot handle 19 to drive the brake control valve 18 to switch. The pressure oil from the motor's starting port B of the second shuttle valve 11 enters the brake 16 cylinder after passing through the brake control valve 18, opening the brake 16. As the pressure at the motor's lowering port increases, when it reaches the opening pressure value of the winch balance valve 12, the pressure at the motor's lowering port A acts on the control end of the winch balance valve 12 through the pipeline, pushing the winch balance valve 12 to switch. The winch balance valve 12 opens, and the motor 13 begins to rotate, thus completing the descent of the load. The accumulator 21 stores high-pressure oil under load lifting conditions. Before the brake 16 is opened, it replenishes the motor's starting port cavity, thereby compensating for the pressure in the motor's starting port cavity and avoiding the heavy-load starting shock problem caused by insufficient motor starting port pressure.

[0048] The accumulator pressure replenishment system replenishes the pressure in the motor inlet cavity before the brake 16 is opened. To ensure this function is achieved, the opening pressure of the hydraulic check valve 20 must be lower than the opening pressure of the brake 16, and the pressure is replenished into the motor inlet cavity before the brake 16 is opened.

[0049] It is worth noting that the two-position two-way solenoid directional valve 22 receives the signal from the force limiter and controls the opening and closing of the pressure replenishment oil circuit, thereby controlling the timing of the accumulator 21 replenishing the pressure in the motor starting cavity. The two-position two-way solenoid directional valve in this solution is only one application example. Other components that can perform the switching function are all within the scope of protection of this patent.

[0050] It is worth noting that the hydraulic control check valve 20 enables the accumulator 21 to be freely flushed and controlled to open and release liquid. The hydraulic control check valve 20 in this solution is only one application example. Other components that can perform similar functions are all within the scope of protection of this patent.

[0051] It is worth noting that the pressure sensor 24 is used to collect the output pressure of the pilot handle 19 and convert the pressure signal into an electrical signal to transmit to the force limiter 23. The pressure sensor in this solution is only one application example. Other components that can perform similar functions, such as pressure relays, are all within the scope of protection of this patent.

[0052] As an alternative, the pressure sensor 24 on the first shuttle valve 7 after the pilot handle 19 outputs pressure, and the control signal of the brake control valve 18 can be eliminated. Instead, the force limiter 23 can be used to determine the percentage of single-rope tension before issuing a signal. Figure 4 As shown.

[0053] Example 2

[0054] The present invention also includes a crane having the torque-balanced winch hydraulic system described in Embodiment 1, which realizes pressure replenishment of the motor starting cavity, solves problems such as pressure shock and vibration noise that occur under heavy load starting conditions of the winch mechanism, improves the smoothness of the heavy load starting action of the winch system, and improves the operating comfort.

Claims

1. A hoisting hydraulic system based on torque balance, characterized in that: The system includes an accumulator pressurization system, which includes a hydraulic check valve (20), an accumulator (21), a two-position two-way solenoid directional valve (22), a force limiter (23), and a pressure sensor (24). The outlet of the hydraulic control check valve (20) is connected to the accumulator (21), and the inlet of the hydraulic control check valve (20) is connected to the oil passage of the motor inlet cavity between the motor (13) inlet B and the hoisting balance valve (12). The pressure sensor (24) is connected to the pilot handle (19) and the force limiter (23) respectively. The pressure sensor (24) is used to collect the pressure of the pilot handle (19) and send it to the force limiter (23). The force limiter (23) is connected to the solenoid coil of the two-position two-way solenoid directional valve (22), and the two-position two-way solenoid directional valve (22) is connected to the control port of the hydraulic check valve (20). When the hoisting is in operation, the oil at the inlet B of the motor (13) fills the accumulator (21) through the hydraulic check valve (20); The force limiter (23) collects the pressure signal output by the pilot handle (19) and the hoisting single rope tension signal. When the pressure signal output by the pilot handle (19) and the hoisting single rope tension signal both reach the corresponding preset threshold, the force limiter (23) sends a signal to drive the two-position two-way solenoid directional valve (22) to switch. The pressure oil from the pilot handle (19) drives the hydraulic control check valve (20) to open in both directions. The hydraulic oil in the accumulator (21) is replenished to the motor (13) starting port B through the hydraulic control check valve (20), thereby pressurizing the accumulator (21) to the motor starting port cavity and realizing the torque balance between the motor starting and ending ports.

2. The hoisting hydraulic system based on torque balance according to claim 1, characterized in that: A brake (16) is provided between the motor (13) and the drum (15), and the opening pressure of the hydraulic check valve (20) is lower than the opening pressure of the brake (16).

3. The hoisting hydraulic system based on torque balance according to claim 2, characterized in that: The brake (16) is a normally closed brake. The brake (16) is connected to the brake control valve (18), which is used to control the brake (16) to open.

4. The hoisting hydraulic system based on torque balance according to claim 1, characterized in that: The pressure sensor (24) is installed on the output oil passage of the pilot handle (19) to collect the output pressure of the pilot handle (19) and convert the output pressure into a current signal and send it to the force limiter (23).

5. The hoisting hydraulic system based on torque balance according to claim 1, characterized in that: The two-position two-way solenoid directional valve (22) receives the signal from the force limiter (23) and controls the opening and closing of the pressure replenishment oil circuit according to the received signal.

6. The hoisting hydraulic system based on torque balance according to claim 1, characterized in that: It also includes a main pump (4), and an electromagnetic reversing valve (9) is installed on the oil line between the main pump (4) and the motor (13). The electromagnetic coil at the lower end of the electromagnetic reversing valve (9) is connected to the first pressure output port of the pilot handle (19), and the electromagnetic coil at the upper end of the electromagnetic reversing valve (9) is connected to the second pressure output port of the pilot handle (19).

7. The hoisting hydraulic system based on torque balance according to claim 6, characterized in that: A winch balance valve (12) is installed on the oil line between the electromagnetic reversing valve (9) and the motor (13).

8. A crane, characterized in that: Includes the hoisting hydraulic system based on torque balance as described in any one of claims 1 to 7.

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