Winch hydraulic system based on moment balance and crane

Abstract

The invention discloses a winch hydraulic system based on moment balance and a crane. The system comprises an energy accumulator pressure supplementing system, and the energy accumulator pressure supplementing system comprises a hydraulic control one-way valve, an energy accumulator, a two-position two-way electromagnetic reversing valve, a force limiter and a pressure sensor; an outlet of the hydraulic control one-way valve is connected with the energy accumulator, and an inlet of the hydraulic control one-way valve is connected to an oil channel of the motor starting opening containing cavity between the motor starting opening B and the winch balance valve. The pressure sensor is connected with the pilot handle and the force limiter. The pressure sensor is used for collecting the pressure of the pilot handle and sending the pressure to the force limiter. The force limiter is connected with an electromagnetic coil of the two-position two-way electromagnetic directional valve, and the two-position two-way electromagnetic directional valve is connected with a control oil port of the hydraulic control one-way valve. The problems of pressure impact, vibration, abnormal sound and the like occurring in the heavy-load starting working condition of the hoisting mechanism can be solved, the heavy-load starting action smoothness of a hoisting system is improved, and the operation comfort is improved.

Description

Technical Field

[0001] The invention relates to a crane, in particular to a hoisting hydraulic system based on moment balance and a crane. Background Art

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

[0003] The hydraulic winch mechanism includes a winch hydraulic system, which drives the winch drum to retract and release the wire rope through a hydraulic motor, and realizes the lifting and lowering of the heavy object by means of the linear displacement change of the wire rope. A brake is set in the winch mechanism, which plays a static braking and locking function when the winch is stationary, ensuring that the heavy object can stop at any position. A balance valve is set in the winch hydraulic system to play a dynamic braking and load holding function at the moment of starting and stopping the winch.

[0004] During the use of the hoisting mechanism of the crane, heavy load conditions often occur. When the heavy object is suspended in the air and remains stationary, the brake plate of the winch reducer bears the load torque applied to the drum by the heavy object through friction. After the brake is closed, the motor rotates in the opposite direction within the allowable range of the transmission chain gap (internal gap of the motor, gap between the motor output shaft and the spline sleeve, gap between the spline sleeve and the friction plate) under the action of the starting pressure (due to the small angle, the motor speed encoder cannot be recognized), and the motor reversal causes the motor starting cavity to become larger, resulting in a rapid drop in pressure (in extreme cases, the pressure is less than 3bar). At the moment when the winch is started again (lifting or lowering), when the brake is opened, the load torque is quickly transmitted from the brake to the hydraulic motor starting cavity. Under the action of the heavy load, the motor builds up the hydraulic torque to lift the load by compressing the starting cavity. Since the balance valve is not open, during this period, the winch mechanism has a short "acceleration-stop" process. Due to the matching clearance of the mechanism (between the motor and the spline, the spline and the friction plate, and the friction plate and the reducer housing), the impact and elastic deformation of the components cause vibration and abnormal noise. This impact can be quickly transmitted to the hoisting mechanism and cause vibration, which will be more obvious if the mechanism is installed on a structure with vibration amplification effect such as a boom. This vibration will reduce the life of the hydraulic seals, reduce the comfort of the operator, and in extreme cases, cause safety problems.

[0005] The hydraulic system of the winch mechanism is divided into an open system and a closed hydraulic system. Both systems have abnormal impact noise when the winch is started under heavy load. Industry technicians have adopted pressure memory control logic for the closed winch system based on its component characteristics, which has solved this problem better. This technology is mainly used to explain the problem of open winch mechanism. The industry has conducted many studies on the problem of abnormal impact noise when the open winch mechanism is started under heavy load, and has also formed many solutions.

[0006] Prior art 1 discloses a winch mechanism, such as Figure 1 As shown, it is mainly composed of a hydraulic oil tank 1, an oil return filter 2, an auxiliary pump 3, a main pump 4, a main pump overflow valve 5, a one-way valve 6, a shuttle valve 7, a pressure compensation valve 8, an electromagnetic reversing valve 9, a motor drop-out overflow valve 10, a shuttle valve 11, a winch balance valve 12, a motor 13, a drum 15, a brake 16, an oil replenishment one-way valve 17, a brake control valve 18, and a pilot handle 19.

[0007] Prior art 2: A Chinese invention patent with publication number CN114933256A discloses a winch start control method, device, equipment and crane, which determines the initial starting current value according to the current lifting weight and the preset hook ratio, controls the pilot proportional control valve, determines the starting compensation current value of the motor according to the motor angle, and adjusts the current to complete the winch start work, thereby achieving smooth heavy load start-up.

[0008] Prior art 3: A Chinese invention patent application with publication number CN203461747U discloses a winch hydraulic system that prevents instantaneous impact at startup. A one-way throttle valve is added to the brake control oil circuit so that the flow rate in the control oil circuit is proportional to the volume of the brake cylinder. The purpose is to optimize the relationship between the brake opening and the motor pressure building rate, thereby solving the impact problem of the lifting mechanism at the moment of startup.

[0009] However, the above prior art has the following shortcomings:

[0010] (1) Regarding the prior art 1: Under heavy-load starting conditions, due to the poor matching of the performance of the main valve, the balance valve, the brake, and the motor, it is easy to cause a large pressure shock during heavy-load starting, which damages the sealing of the hydraulic system and the reliability of the components. In addition, the vibration and abnormal noise caused by the starting shock seriously affect the health of the operator;

[0011] (2) Regarding the existing technology 2: Due to the clearance of the winch transmission chain, the motor pressure building rate is slow during heavy-load starting, which affects the responsiveness of the winch heavy-load starting.

[0012] (3) Regarding the existing technology 3: The measures taken to deal with the heavy-load start-up impact of the winch mechanism, such as setting damping in the brake control oil circuit, delaying the brake opening time, etc., will affect the response time of the winch system. In the winch landing condition, there is also a risk of aggravating the brake friction plate; the solution that relies too much on electronic components and program judgment is not feasible for implementation on hydraulic pilot products, and cannot solve the problem of abnormal noise caused by heavy-load start-up impact of winches of non-electronically controlled products. Summary of the invention

[0013] Purpose of the invention: The purpose of the present 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 caused by the heavy-load starting condition of the winch mechanism, improve the smoothness of the heavy-load starting action of the winch system, and improve the operating comfort.

[0014] Technical solution: A winch hydraulic system based on torque balance of the present invention includes an accumulator pressure compensation system, wherein the accumulator pressure compensation system includes a hydraulically controlled one-way valve, an accumulator, a two-position two-way electromagnetic reversing valve, a force limiter, and a pressure sensor;

[0015] The outlet of the hydraulically controlled one-way valve is connected to the accumulator, and the inlet of the hydraulically controlled one-way 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, and 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 electromagnetic coil of the two-position two-way electromagnetic reversing valve, and the two-position two-way electromagnetic reversing valve is connected to the control oil port of the hydraulically controlled one-way valve.

[0018] Furthermore, when the winch is in operation, the oil at the starting port B of the motor fills the accumulator through the hydraulically controlled one-way 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 the pressure signal output by the pilot handle and the single-rope tension signal of the winch both reach the corresponding preset thresholds, the force limiter sends a signal to drive the two-position two-way electromagnetic reversing valve to reverse, and the pressure oil from the pilot handle drives the hydraulically controlled one-way valve to open in both directions. The hydraulic oil in the accumulator is replenished to the motor starting port B through the hydraulically controlled one-way valve, thereby replenishing the pressure of the accumulator to the motor starting port cavity, thereby achieving torque balance between the motor starting and ending ports.

[0020] Furthermore, a brake is provided between the motor and the reel, and the opening pressure of the hydraulically controlled one-way valve is lower than the opening pressure of the brake, so that the motor opening cavity is replenished before the brake is opened.

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

[0022] Furthermore, the pressure sensor is arranged on the output oil channel of the pilot handle, and is used to collect the output pressure of the pilot handle, and convert the output pressure into a current signal and then send it to the force limiter.

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

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

[0025] Furthermore, a winch balancing valve is arranged on the oil circuit between the electromagnetic reversing valve and the motor.

[0026] Based on the same inventive concept, a crane of the present invention comprises the above-mentioned hoisting hydraulic system based on moment balance.

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

[0028] Effectively suppress or eliminate the problem of abnormal noise caused by impact during heavy-load starting of the winch. Specifically, under the heavy-load starting condition of the winch mechanism, pressurized oil is added to the motor starting chamber to balance the gravity torque of the weight on the drum, so that the motor mechanism and the brake are started under nearly torque-balanced conditions, avoiding the pressure shock under heavy-load starting conditions in the prior art and the abnormal vibration noise caused by the impact, improving the stress condition of the mechanism and reducing the adverse effects on the sealing performance of the hydraulic system.

[0029] Compared with the heavy-load starting responsiveness caused by the slow pressure building rate of the motor starting cavity in the prior art, the present invention speeds up the pressure building rate of the motor starting cavity and accelerates the response speed of the system heavy-load lifting condition by supplementing the pressure in the motor starting cavity without changing the system oil supply flow gradient.

[0030] The invention relies on the force limiter to process data, and all engineering cranes are provided with the force limiter, so the modification cost is low and the applicability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 2 A structural schematic diagram of a winch hydraulic system based on moment balance disclosed in an embodiment of the present invention;

[0033] Figure 3 It is a working flow chart of the accumulator pressure compensation system disclosed in an embodiment of the present invention;

[0034] Figure 4 The present invention is a schematic structural diagram of another winch hydraulic system based on torque balance disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings of the specification.

[0036] Example 1

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

[0038] Among them, the main pump 4 is used to provide a power oil source for the motor 13 to operate. The electromagnetic reversing valve 9 is set on the oil path between the main pump 4 and the motor 13. By switching the working position of the electromagnetic reversing valve 9, the switching between the working port of the main pump 4 and the oil port of the motor 13 is realized, thereby changing the rotation direction of the motor 13. In order to achieve precise control of the motor speed, a pressure compensation valve 8 is provided on the electromagnetic reversing valve 9. 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. The switching power of the electromagnetic reversing 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 (at the same time, only one port can output working pressure). The output pressure of port 1 (i.e., the first pressure output port) of the pilot handle 19 acts on the lower end of the electromagnetic reversing valve 9, driving the electromagnetic reversing valve 9 to work in the lower position of the valve core working position (heavy object rising state). The output pressure of port 2 (i.e., the second pressure output port) of the pilot handle 19 acts on the upper end of the electromagnetic reversing valve 9, driving the electromagnetic reversing valve 9 to work in the upper position of the valve core working position (heavy object descending state). If there is no pressure output from ports 1 and 2 of the pilot handle 19, the electromagnetic reversing valve 9 works in the middle position of the valve core under the action of the reset spring. At this time, the oil circuit from the oil pump to the motor is cut off, and the winch movement stops. The oil source of the pilot handle 19 comes from the auxiliary pump 3. The winch balance valve 12 is arranged on the oil circuit between the electromagnetic reversing valve 9 and the motor 13, and is directly connected to the motor oil port by bolts in actual use (the motor oil port for installing the balance valve is also called the motor starting port by professional technicians. For the sake of convenience, it is referred to as the motor B port below, and the other motor port is referred to as the motor A port). When the electromagnetic reversing valve 9 is working in the lower position of the valve core, the pressure oil source from the main pump 4 flows into the motor B port through the one-way valve in the winch balance valve 12 to drive the motor to rotate, thereby lifting the heavy object. After the electromagnetic reversing valve 9 is reversed, the pressure oil source from the main pump 4 reaches the A port of the motor 13, and the pressure oil of the A port of the motor 13 acts on the control end of the winch balance valve 12 through the pipeline, pushing the winch balance valve 12 to reverse, and the oil returns to the oil tank through the throttle port in the winch balance valve 12, thereby realizing the rotation of the motor and the lowering of the heavy object. The brake 16 is arranged between the motor 13 and the drum 15. The brake 16 is a normally closed brake. The brake 16 is connected to the brake control valve 18. The brake control valve 18 is used to control the opening of the brake 16. During the operation of the above-mentioned hoisting mechanism, the brake 16 plays a decisive role. If the brake 16 is not opened, the drum 15 cannot rotate. The brake is a normally closed brake. The pressure oil from the brake control valve 18 acts on the brake 16 cylinder to open the brake. The reversing pressure of the brake control valve 18 comes from the shuttle valve 7. The function of the shuttle valve 7 is to extract the output pressure of the pilot handle 19. The input pressure of the brake control valve 18 is taken from the shuttle valve 11. The function of the shuttle valve 11 is to extract the pressure of the motor working port.

[0039] The present invention adds an accumulator pressure compensation system on the basis of the traditional lifting hydraulic system, and uses the accumulator pressure compensation system to compensate the pressure of the motor starting cavity between the motor 13 and the winch balance valve 12 to achieve motor torque balance, thereby suppressing or eliminating the impact and abnormal noise problems caused by the motor when it is started under heavy load.

[0040] The accumulator pressure compensation system includes a hydraulically controlled one-way valve 20, an accumulator 21, a two-position two-way electromagnetic reversing valve 22, a force limiter 23, and a pressure sensor 24. The outlet of the hydraulically controlled one-way valve 20 is connected to the accumulator 21, and the inlet of the hydraulically controlled one-way valve 20 is connected to the oil passage of the motor starting chamber between the starting port B of the horse 13 and the winch balance valve 12. The pressure sensor 24 is connected to the pilot handle 19 and the force limiter 23 respectively, and 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 arranged on the output oil passage of the pilot handle 19, and is used 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. The force limiter 23 is connected to the electromagnetic coil of the two-position two-way electromagnetic reversing valve 22, and the two-position two-way electromagnetic reversing valve 22 is connected to the control oil port of the hydraulically controlled one-way valve 20. The two-position two-way electromagnetic reversing valve 22 receives a signal from the force limiter 23 and controls the opening and closing of the pressure compensation oil circuit according to the received signal.

[0041] The accumulator pressure replenishment system is connected to the motor start-up cavity (between the motor 13 start-up B and the winch balance valve 12) through a hydraulically controlled one-way valve 20. When the winch is in action, the oil at the motor start-up B fills the accumulator 21 through the hydraulically controlled one-way valve 20. The force limiter 23 collects the pressure signal output by the pilot handle 19 and the winch single rope tension signal, and sends a signal to the two-position two-way electromagnetic reversing valve 22 after program judgment to determine the timing for the accumulator 21 to replenish the pressure of the motor start-up cavity. When the conditions are met that the single rope tension exceeds X% of the rated tension and the handle output pressure increases from 0 bar to Y bar, the motor start-up cavity begins to be pressurized. The details are as follows:

[0042] like Figure 2 and Figure 3As shown, the oil at the starting port B of the motor 13 is used to charge the accumulator 21 through the hydraulically controlled one-way valve 20. The force limiter 23 collects the pressure signal output by the pilot handle 19 and the single-rope tension signal of the winch. When the pressure signal output by the pilot handle 19 and the single-rope tension signal of the winch reach the corresponding preset threshold value, the force limiter 23 sends a signal to drive the two-position two-way electromagnetic reversing valve 22 to change direction, and the pressure oil from the pilot handle 19 drives the hydraulically controlled one-way valve 20 to open in both directions. The hydraulic oil in the accumulator 21 is supplemented to the starting port B of the motor 13 through the hydraulically controlled one-way valve 20, so that the accumulator 21 replenishes the pressure of the motor starting port cavity to achieve the torque balance between the motor starting and ending ports. Among them, the winch single rope tension signal is obtained in the following way: 1. According to the crane torque balance principle, according to the collected hydraulic system pressure of the variable-length oil cylinder, the load torque borne by the crane winch hook is calculated; 2. According to the boom length and variable-length angle collected by the system, the load arm length at the hook is calculated; 3. According to the load torque and load arm values ​​of the first two steps, the load weight borne by the hook is calculated; 4. According to the hook load weight in the third step, combined with the winch wire rope multiplier, the winch single rope tension value is obtained.

[0043] The main working principle of the present invention is as follows (based on the working conditions of hoisting, stopping and falling from the ground with a winch load):

[0044] Winch lifting process (heavy objects start to be lifted from the ground): the working port 1 of the pilot handle 19 outputs pressure, which acts on the lower end of the electromagnetic reversing valve 9. The electromagnetic reversing valve 9 acts on the lower position of the valve core. The oil circuit from the main pump 4 to the starting port B of the motor 13 is connected, and the oil source discharged from the main pump 4 enters the B port of the motor 13 through the built-in one-way valve of the winch balance valve 12. Since the brake 16 is not opened, the drum 15 cannot move, and the starting port B of the motor 13 gradually builds up pressure. The starting port oil charges the accumulator 21 through the hydraulically controlled one-way valve 20. Since the single rope tension and the handle output pressure signal both meet the conditions, the force limiter 23 sends a signal to drive the two-position two-way solenoid valve reversing valve 22 to reverse (the opening time is set to 50ms, and this value can be adjusted according to actual conditions), and the hydraulically controlled one-way valve 20 opens in both directions. After 50ms, the hydraulically controlled one-way valve 20 is closed and the accumulator 21 maintains pressure. At the same time, the first shuttle valve 7 takes the pressure from the output port 1 of the pilot handle 19 to drive the brake control valve 18 to change direction, and the pressure oil from the motor starting port B of the second shuttle valve 11 enters the oil cylinder of the brake 16 through the brake control valve 18 to open the brake 16. When the pushing torque of the motor 13 starting port pressure acting on the motor 13 reaches the load torque of the heavy object, the heavy object begins to lift.

[0045] Winch static state: the angle of the pilot handle 19 gradually decreases, its output working port 1 gradually decreases until it reaches zero, the pressure at the lower end of the electromagnetic reversing valve 9 decreases, and the valve core of the electromagnetic reversing 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 the minimum by reducing the displacement), the B port oil circuit connected to the motor 13 is cut off, and there is no power oil flowing in the working chamber of the motor 13. Due to the action of the one-way valve inside the winch balance valve 12, the motor B port chamber forms the highest system pressure due to the load imposed on the drum by the heavy object. As the pressure of the motor A and B ports decreases, the brake 16 is closed, and the brake 16 bears the gravity load torque on the winch through the friction torque of the friction plate to keep the load static. The motor 13 rotates in the opposite direction within the allowable range of the transmission chain clearance (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) (the motor speed encoder cannot recognize it due to the small angle). The reverse rotation of the motor 13 causes the motor starting cavity to become larger, resulting in a rapid drop in pressure (in extreme cases, the pressure is less than 3 bar).

[0046] Winch descent process: After the winch has experienced the loaded hovering condition, the pressure in the motor start chamber is almost zero (there is leakage in the winch hydraulic component).

[0047] The output pressure of the working port 2 of the pilot handle 19 gradually increases, acting on the upper end of the electromagnetic reversing valve 9, and the electromagnetic reversing valve 19 gradually switches to the upper position of the valve core. The oil circuit from the main pump 4 to the motor 13 port A is connected, and the oil source discharged from the main pump 4 enters the motor port A. Since the brake 16 and the winch balance valve 12 are not opened, the drum 15 cannot move. In this process, the force limiter 23 collects the pilot handle 19 pressure sent by the pressure sensor 24 and increases from 0bar to Ybar. In addition, the single rope pressure signal reaches X% of the rated pressure, meeting the pre-set pressure compensation conditions of the program. The force limiter 23 sends a signal to drive the two-position two-way electromagnetic reversing valve 22 to change direction, and 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 start port cavity. As the opening of the electromagnetic reversing valve 9 becomes larger and larger, the pressure at the motor 12 port A is gradually built up, and the first shuttle valve 7 takes the pressure of the output port 2 of the pilot handle 19 to drive the brake control valve 18 to change direction. The pressure oil from the motor port B of the second shuttle valve 11 passes through the brake control valve 18 and enters the brake 16 cylinder to open the brake 16. As the motor port pressure increases, when it reaches the opening pressure value of the winch balance valve 12, the pressure of the motor port A acts on the control end of the winch balance valve 12 through the pipeline, pushing the winch balance valve 12 to change direction, the winch balance valve 12 opens, and the motor 13 starts to rotate, completing the heavy object lowering action. The oil stored in the accumulator 21 is high-pressure oil under load lifting conditions, which is added to the motor port cavity before the brake 16 is opened, thereby making up for the pressure of the motor port cavity and avoiding the heavy load starting impact problem caused by insufficient motor port pressure.

[0048] The accumulator pressure replenishing system has the function of replenishing the pressure of the motor starting cavity before the brake 16 is opened. To ensure the realization of this function, the opening pressure of the hydraulically controlled one-way valve 20 must be lower than the opening pressure of the brake 16, and the pressure is replenished into the motor starting cavity before the brake 16 is opened.

[0049] It is worth noting that the two-position two-way electromagnetic reversing valve 22 receives the signal from the force limiter and controls the opening and closing of the pressure-compensating oil circuit, thereby controlling the timing of the accumulator 21 to compress the motor starting chamber. The two-position two-way electromagnetic reversing valve in this scheme is only one of the application examples, and the other components that can perform the reversing function all fall within the scope of protection of this patent.

[0050] It is worth noting that the hydraulically controlled one-way valve 20 plays the role of free charging of the accumulator 21 and controlled opening to release the liquid. The hydraulically controlled one-way valve 20 in this solution is only one application example, and other components that can play similar functions all fall 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 at the same time convert the pressure signal into an electrical signal and transmit it to the force limiter 23. The pressure sensor in this solution is only one application example, and other components that can perform similar functions, such as pressure relays, all fall within the scope of protection of this patent.

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

[0053] Example 2

[0054] The present invention also includes a crane having a hoisting hydraulic system based on torque balance as described in Example 1, which can realize pressure replenishment of the motor starting cavity, solve problems such as pressure shock, vibration and abnormal noise occurring during the heavy-load starting condition of the hoisting mechanism, improve the smoothness of the heavy-load starting action of the hoisting system, and improve operating comfort.

Claims

1. A winch hydraulic system based on moment balance, characterized in that: It comprises an accumulator pressure compensation system, wherein the accumulator pressure compensation system comprises a hydraulically controlled one-way valve (20), an accumulator (21), a two-position two-way electromagnetic reversing valve (22), a force limiter (23), and a pressure sensor (24); The outlet of the hydraulically controlled one-way valve (20) is connected to the accumulator (21), and the inlet of the hydraulically controlled one-way valve (20) is connected to the oil passage of the motor opening chamber between the motor opening B and the winch balance valve (12); The pressure sensor (24) is connected to the pilot handle (19) and the force limiter (23) respectively, and 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 electromagnetic coil of a two-position two-way electromagnetic reversing valve (22), and the two-position two-way electromagnetic reversing valve (22) is connected to the control oil port of the hydraulically controlled one-way valve (20).

2. The winch hydraulic system based on torque balance according to claim 1, characterized in that: When the winch is in operation, the oil at the port B of the motor (13) fills the accumulator (21) through the hydraulically controlled one-way valve (20).

3. The winch hydraulic system based on torque balance according to claim 2 is characterized in that: The force limiter (23) collects the pressure signal output by the pilot handle (19) and the winch single rope tension signal. When the pressure signal output by the pilot handle (19) and the winch single rope tension signal both reach corresponding preset threshold values, the force limiter (23) sends a signal to drive the two-position two-way electromagnetic reversing valve (22) to switch direction, and the pressure oil from the pilot handle (19) drives the hydraulically controlled one-way valve (20) to open in both directions. The hydraulic oil in the accumulator (21) is supplemented to the motor (13) start port B through the hydraulically controlled one-way valve (20), thereby compensating the pressure of the accumulator (21) to the motor start port cavity, thereby achieving torque balance between the motor start port and the end port.

4. The winch hydraulic system based on moment balance according to claim 1, characterized in that: A brake (16) is provided between the motor (13) and the reel (15), and the opening pressure of the hydraulically controlled one-way valve (20) is lower than the opening pressure of the brake (16).

5. The winch hydraulic system based on moment balance according to claim 4 is characterized in that: The brake (16) is a normally closed brake. The brake (16) is connected to a brake control valve (18). The brake control valve (18) is used to control the opening of the brake (16).

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

7. The winch hydraulic system based on moment balance according to claim 1, characterized in that: The two-position two-way electromagnetic reversing valve (22) receives a signal from the force limiter (23), and controls the opening and closing of the pressure compensation oil circuit according to the received signal.

8. The winch hydraulic system based on moment balance according to claim 1, characterized in that: It also includes a main pump (4), wherein an electromagnetic reversing valve (9) is arranged on the oil circuit 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).

9. The winch hydraulic system based on moment balance according to claim 8, characterized in that: A hoisting balance valve (12) is arranged on the oil circuit between the electromagnetic reversing valve (9) and the motor (13).

10. A crane, characterized in that: A winch hydraulic system based on torque balance comprising any one of claims 1 to 9.

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