Crane valve control energy-saving hydraulic system

Abstract

A first oil pump and an oil tank are respectively connected with a first working oil port through a first reversing valve, a second working oil port is connected with the oil tank, and a second oil pump is connected with the second working oil port. Compared with the prior art, high-pressure oil of the first oil pump is input into the first working oil port of the execution unit and is discharged from the second working oil port after acting, and heavy-load heavy objects are lifted; when a heavy object needs to be descended, the first reversing valve is used for changing flowing of hydraulic oil, the hydraulic oil is discharged from the first working oil port where oil enters originally, meanwhile, the second oil pump is used for supplementing oil to the second working oil port to avoid air suction, and the execution unit can work reversely in the descending process; heavy loads are utilized to overcome friction force of the system and provide acceleration required by descending, so that the heavy objects can safely, reliably and automatically descend by means of self-gravity, energy utilization efficiency is improved, and system heating is reduced.

Description

Technical Field

[0001] This invention relates to the field of lifting equipment technology, and in particular to a valve-controlled energy-saving hydraulic system for cranes. Background Technology

[0002] Offshore cranes are specialized lifting equipment designed specifically for marine environments. They are typically installed on ships or floating platforms to perform tasks such as cargo transport between ships, replenishment at sea, and deployment and recovery of underwater equipment. Unlike land-based cranes, they must cope with complex environmental loads such as wind, waves, and currents, as well as the significant challenges posed by the ship's rolling motion.

[0003] In hydraulic crane systems, particularly during heavy-duty operations, low energy efficiency is a significant problem. The core reason lies in the fact that these systems typically employ a "throttling speed control" method to regulate the descent speed of the load. This process requires throttling the hydraulic oil through valves, converting the immense gravitational potential energy generated during the load's descent into heat energy, which is then dissipated. This not only wastes valuable energy but also causes a rapid increase in the oil temperature throughout the hydraulic system. Excessively high oil temperatures accelerate the aging of the hydraulic oil and seals, increase the risk of system leaks, and ultimately reduce the lifespan of hydraulic components.

[0004] Therefore, it is necessary to develop a new type of valve-controlled energy-saving hydraulic system for cranes to improve the aforementioned problems in related technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a valve-controlled energy-saving hydraulic system for cranes, which can effectively utilize the gravitational potential energy of heavy objects falling under heavy loads, improve energy utilization efficiency, and reduce system heat generation.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] This invention provides a valve-controlled energy-saving hydraulic system for cranes, comprising:

[0008] Power unit, control unit, execution unit, and auxiliary unit;

[0009] The power unit includes a first oil pump and a second oil pump; the control unit includes a first directional valve; the execution unit includes a first working oil port and a second working oil port; the auxiliary unit includes an oil tank.

[0010] The first oil pump and the oil tank are respectively connected to the first working oil port via the first reversing valve, for oil to enter from the first working oil port when the heavy object rises and to return oil from the first working oil port when the heavy object falls due to its own weight; the second working oil port is connected to the oil tank, for oil to return from the second working oil port when the heavy object rises; the second oil pump is connected to the second working oil port, for oil to be replenished from the second working oil port when the heavy object falls due to its own weight.

[0011] Furthermore, the auxiliary unit includes a first oil circuit and a second oil circuit, the first directional valve is a three-way valve; the first oil circuit is connected to the first working oil port and the working oil port of the first directional valve respectively; the second oil circuit is connected to the second working oil port and the oil tank; the first oil pump and the oil tank are respectively connected to the oil inlet and oil return port of the first directional valve.

[0012] Furthermore, a solenoid valve and an overflow valve are sequentially arranged in the second oil circuit extending from the second working oil port to the oil tank.

[0013] Furthermore, the auxiliary unit includes a first oil replenishment branch, which is connected to the second oil pump and the second working oil port respectively.

[0014] Furthermore, the auxiliary unit includes a second oil replenishment branch, which is connected to the second oil pump and the first working oil port respectively, and is used to replenish oil from the first working oil port when the heavy object rises.

[0015] Furthermore, the auxiliary unit includes an oil replenishment bypass, which connects the oil tank and the second working oil port. A one-way valve is provided on the oil replenishment bypass for replenishing oil from the second working oil port when the weight of the heavy object decreases.

[0016] Furthermore, it also includes a detection unit for acquiring lifting load data; the control unit further includes a processor and a second reversing valve, the processor being connected to the detection unit, the first reversing valve and the second reversing valve respectively, for turning on the first reversing valve or the second reversing valve according to the comparison result of the lifting load data and the set value.

[0017] Furthermore, the second directional valve is a four-way valve, the first working port and the second working port are respectively connected to the working port of the second directional valve, and the first oil pump and the oil tank are respectively connected to the oil inlet and oil return port of the second directional valve.

[0018] Furthermore, it also includes a detection unit for acquiring lifting load data; the first oil pump is a constant pressure variable pump, and the execution unit is a lifting variable motor; the control unit also includes a processor, which is connected to the detection unit, the first oil pump and the execution unit respectively, for adjusting the output flow rate and motor displacement according to the lifting load data.

[0019] Furthermore, the first directional valve and the second directional valve are electro-hydraulic proportional directional valves.

[0020] Compared with the prior art, the crane valve-controlled energy-saving hydraulic system provided by the present invention has the following beneficial effects:

[0021] 1. In the hydraulic system of the present invention, the first oil pump and the oil tank are respectively connected to the first working port via the first reversing valve, the second working port is connected to the oil tank, and the second oil pump is connected to the second working port. The high-pressure oil from the first oil pump is input into the first working port of the actuator, and after doing work, it is discharged from the second working port to realize the lifting of heavy loads. When it is necessary to lower the heavy load, the first reversing valve is used to change the flow of hydraulic oil, and hydraulic oil is discharged from the original inlet of the first working port. At the same time, the second oil pump replenishes oil to the second working port to avoid cavitation, so that the actuator can work in reverse during the descent process, using the heavy load to overcome the system friction and provide the acceleration required for descent, thereby realizing that the heavy load can be safely and reliably lowered automatically by its own weight, which is beneficial to improving energy utilization efficiency and reducing system heat generation.

[0022] 2. The first directional valve is a three-way valve. The first oil circuit is connected to the first working oil port and the working oil port of the first directional valve. The second oil circuit is connected to the second working oil port and the oil tank. The first oil pump and the oil tank are connected to the oil inlet and oil return port of the first directional valve, respectively. Under the control of the three-way valve, when the heavy-duty lifting and lowering actuators are working in both directions, the oil inlet and oil return can be achieved through the first working oil port and the first oil circuit. The second oil circuit works in cooperation with the first oil circuit to provide a structural foundation for the lifting of heavy objects and the lowering of their own weight.

[0023] 3. The second oil circuit is equipped with a solenoid valve and a relief valve in sequence from the second working oil port to the oil tank. The solenoid valve opens when the heavy load is lifted to open the return oil circuit. The relief valve provides a certain back pressure to increase the stability of the system for heavy load return oil. It also automatically opens to release pressure when the system pressure exceeds the set value to prevent heavy load from damaging the system. The sequential arrangement of the solenoid valve and the relief valve improves the system safety and operational reliability.

[0024] 4. The auxiliary unit includes a first oil replenishment branch, which is connected to the second oil pump and the second working oil port respectively. When the actuator cavity needs to be replenished with oil during the descent of the heavy object, the second oil pump can provide hydraulic oil in time to avoid vacuum or air intake, thereby preventing cavitation.

[0025] 5. The auxiliary unit includes a second oil replenishment branch, which is connected to the second oil pump and the first working oil port respectively, to meet the oil replenishment needs under the condition of heavy object lifting. When the first working oil port generates instantaneous negative pressure due to the heavy load of the actuator, the second oil pump can replenish the oil in time to avoid cavitation and unstable operation. By replenishing oil through the independent second oil pump, the normal working pressure of the main oil circuit is not interfered with, which not only ensures the stability of the heavy object lifting, but also improves the system response speed.

[0026] 6. The auxiliary unit includes a replenishment bypass, which connects to the oil tank and the second working oil port. A check valve is installed on the replenishment bypass. When the weight of the object descends, a negative pressure easily forms at the second working oil port. The check valve automatically opens, allowing hydraulic oil from the tank to be replenished. This passive replenishment requires no additional energy consumption, has a simple and reliable structure, and can assist the active replenishment work of the second oil pump. Simultaneously, the check valve design prevents oil backflow, ensuring system safety.

[0027] 7. The hydraulic system also includes a detection unit to acquire lifting load data. By detecting the load size in real time, it automatically selects a suitable hydraulic circuit. Under light load, the first directional valve is closed and the second directional valve is used. The second directional valve is a four-way valve. The first working port and the second working port are respectively connected to the working port of the second directional valve. The first oil pump and the oil tank are respectively connected to the inlet and return ports of the second directional valve. The complete oil circuit design of the four-way valve enables the second directional valve to independently construct a complete hydraulic circulation system, reducing energy consumption and system heat generation under light load conditions. The intelligent switching control strategy realizes the optimal allocation of hydraulic resources.

[0028] 8. The detection unit of the hydraulic system connects the first oil pump and the execution unit. The first oil pump is a constant pressure variable pump, and the execution unit is a lifting variable motor. The constant pressure variable pump automatically adjusts the output flow according to the load requirements, avoiding the energy waste of a fixed displacement pump. The lifting variable motor can adjust the displacement according to the load size, increasing torque under heavy load and increasing speed under light load. The processor coordinates and controls the system to maintain the best matching state under both light and heavy working conditions, significantly improving energy utilization efficiency. Attached Figure Description

[0029] Figure 1 This is a hydraulic schematic diagram of the crane valve-controlled energy-saving hydraulic system in an embodiment of the present invention.

[0030] Figure label:

[0031] 11. Second oil pump; 12. First oil pump;

[0032] 21. Check valve; 22. Check valve; 23. Check valve; 24. Check valve; 25. Check valve;

[0033] 31. Relief valve; 32. Relief valve; 33. Relief valve;

[0034] 4. Pressure reducing valve;

[0035] 51. Solenoid valve; 52. Solenoid valve;

[0036] 61. Second directional control valve; 62. First directional control valve;

[0037] 7. Cooler;

[0038] 8. Accumulator;

[0039] 9. Execution Unit. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0041] An embodiment of the present invention provides a valve-controlled energy-saving hydraulic system for cranes, comprising:

[0042] Power unit, control unit, execution unit 9 and auxiliary unit;

[0043] The power unit includes a first oil pump 12 and a second oil pump 11; the control unit includes a first reversing valve 62; the execution unit 9 includes a first working oil port A and a second working oil port B; the auxiliary unit includes an oil tank.

[0044] The first oil pump 12 and the oil tank are respectively connected to the first working oil port A via the first reversing valve 62, which is used to feed oil from the first working oil port A when the heavy object rises and to return oil from the first working oil port A when the heavy object falls due to its own weight; the second working oil port B is connected to the oil tank, which is used to return oil from the second working oil port B when the heavy object rises; the second oil pump 11 is connected to the second working oil port B, which is used to replenish oil from the second working oil port B when the heavy object falls due to its own weight.

[0045] Specifically, the execution unit 9 is used to drive the winch of the crane. The relief valve 31 is connected to the oil outlet line of the first oil pump 12 and is used to limit the maximum pressure of the replenishment circuit; the relief valve 32 is connected to the oil outlet line of the second oil pump 11 and protects the main oil circuit. A check valve 22 is provided at the working oil port A of the first oil pump 12, and a check valve 21 is provided at the working oil port A of the second oil pump 11.

[0046] In some embodiments of the present invention, the auxiliary unit includes a first oil circuit and a second oil circuit, and the first reversing valve 62 is a three-way valve; the first oil circuit is connected to the first working oil port A and the working oil port of the first reversing valve 62 respectively; the second oil circuit is connected to the second working oil port B and the oil tank; the first oil pump 12 and the oil tank are respectively connected to the oil inlet and oil return port of the first reversing valve 62.

[0047] Specifically, the first directional valve 62 is a three-position four-way electro-hydraulic proportional valve that controls the operating speed and direction of the actuator 9.

[0048] In some embodiments of the present invention, a solenoid valve 52 and an overflow valve 33 are sequentially arranged in the direction of the second oil passage extending from the second working oil port B to the oil tank. The solenoid valve 52 controls the on / off connection between the low-pressure side of the execution unit 9 and the overflow valve 33.

[0049] In some embodiments of the present invention, the auxiliary unit includes a first oil replenishment branch, which is connected to the second oil pump 11 and the second working oil port B.

[0050] In some embodiments of the present invention, the auxiliary unit includes a second oil replenishment branch, which is connected to the second oil pump 11 and the first working oil port A, respectively, and is used to replenish oil from the first working oil port A when the heavy object rises.

[0051] In some specific embodiments, the first oil replenishment branch is connected to the second oil circuit, and a one-way valve 24 is provided on the first oil replenishment branch. The second oil replenishment branch is connected to the first oil circuit, and a one-way valve 23 is provided on the second oil replenishment branch.

[0052] In some embodiments of the present invention, the auxiliary unit includes an oil replenishment bypass, which is connected to the oil tank and connected to the second working oil port B. A one-way valve 25 is provided on the oil replenishment bypass for replenishing oil from the second working oil port B when the weight of the heavy object decreases.

[0053] Specifically, the oil replenishment bypass is connected in parallel to both sides of the solenoid valve 52 and the relief valve 33 on the second oil line.

[0054] In some embodiments of the present invention, a detection unit is further included for acquiring lifting load data; the control unit further includes a processor and a second reversing valve 61, the processor being connected to the detection unit, the first reversing valve 62 and the second reversing valve 61 respectively, for turning on the first reversing valve 62 or the second reversing valve 61 according to the comparison result of the lifting load data and the set value.

[0055] In some embodiments of the present invention, the second reversing valve 61 is a four-way valve, the first working oil port A and the second working oil port B are respectively connected to the working oil ports of the second reversing valve 61, and the first oil pump 12 and the oil tank are respectively connected to the oil inlet and oil return port of the second reversing valve 61.

[0056] Specifically, the second directional valve 61 is a three-position four-way electro-hydraulic proportional valve that controls the operating speed and direction of the actuator 9.

[0057] In some specific embodiments, a cooler 7 is also provided on the pipeline of hydraulic oil before it enters the oil tank to reduce the temperature of the return oil; specifically, a cooler 7 is provided between the overflow valve 33, the return port of the first directional valve 62, the return port of the second directional valve 61, the check valve 25 and the oil tank.

[0058] In some specific embodiments, the first oil pump 12 is connected to the brake of the actuator 9 via the pressure reducing valve 4 and the solenoid valve 51.

[0059] In some specific embodiments, the pipeline between the first reversing valve 62, the second reversing valve 61, and the solenoid valve 51 and the first oil pump 12 is connected to an accumulator 8, which stores energy and replenishes oil under wave compensation conditions, thereby reducing the installed power of the motor and achieving energy-saving effect.

[0060] In some embodiments of the present invention, a detection unit is further included for acquiring lifting load data; the first oil pump 12 is a constant pressure variable pump, and the execution unit 9 is a lifting variable motor; the control unit further includes a processor, which is connected to the detection unit, the first oil pump 12 and the execution unit 9 respectively, for adjusting the output flow rate and motor displacement according to the lifting load data.

[0061] In some specific embodiments, the detection unit includes a weight sensor connected in series on the load transmission path at the end of the lifting equipment. It can be a point of force application on the wire rope, a connection point of the lifting device, or other such location. This invention does not limit this.

[0062] In some specific embodiments, the lifting load data is the actual weight of the cargo. The processor determines whether the lifting equipment is operating under heavy or light load based on lifting status data such as the working radius, boom angle, boom length, and lifting height of the lifting equipment, combined with the comparison between the actual weight of the cargo and the set value. Then, it controls the hydraulic system to perform the lifting operation through the corresponding first reversing valve 62 or second reversing valve 61.

[0063] In some specific embodiments, the processor may be a dedicated controller, a programmable logic controller, or an industrial computer, etc., and the present invention does not limit this.

[0064] In some specific embodiments, the control of the first reversing valve 62 or the second reversing valve 61 by the processor based on the lifting load data, as well as the adjustment of the output flow of the first oil pump 12 and the motor displacement of the execution unit 9, can all be achieved by existing technologies known to those skilled in the art, and therefore will not be described in detail here.

[0065] In some specific embodiments, the first working oil port A or the second working oil port B connected to the execution unit 9 can be achieved by connecting to the first oil passage or the second oil passage.

[0066] The hydraulic system for cranes provided by this invention can change its working mode according to light or heavy load conditions:

[0067] Under light load conditions, the actuator 9 adjusts the displacement according to the cargo load. When the solenoid valve 51 is energized, the brake of the actuator 9 is released; the processor, combined with the signal from the detection unit, drives the actuator 9 to raise and lower the cargo by controlling the second directional valve 61. Specifically, when YV1 of the second directional valve 61 is energized, the cargo rises; when YV2 of the second directional valve 61 is energized, the cargo lowers. It should be noted that the cargo lowering is driven by the actuator 9, not by the cargo's own weight. The aforementioned light load conditions include unloaded conditions.

[0068] Under heavy load conditions, the actuator 9 adjusts the displacement according to the cargo load. When the solenoid valve 51 is energized, the brake of the actuator 9 is released; the processor, combined with the signal from the detection unit, drives the actuator 9 to raise and lower the cargo by controlling the first directional valve 62. Specifically, when YV3 of the first directional valve 62 is energized and the solenoid valve 52 is simultaneously energized, the cargo rises; when YV4 of the first directional valve 62 is energized, the cargo lowers. It should be noted that the cargo lowers by its own weight.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0071] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0072] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0073] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0074] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A valve-controlled energy-saving hydraulic system for cranes, characterized in that, include: Power unit, control unit, execution unit (9) and auxiliary unit; The power unit includes a first oil pump (12) and a second oil pump (11); the control unit includes a first directional valve (62); the execution unit (9) includes a first working oil port and a second working oil port; the auxiliary unit includes an oil tank; The first oil pump (12) and the oil tank are respectively connected to the first working oil port via the first reversing valve (62) for oil to enter from the first working oil port when the heavy object rises and return oil from the first working oil port when the heavy object falls due to its own weight; the second working oil port is connected to the oil tank for oil to return from the second working oil port when the heavy object rises; the second oil pump (11) is connected to the second working oil port for oil to be replenished from the second working oil port when the heavy object falls due to its own weight.

2. The hydraulic system according to claim 1, characterized in that, The auxiliary unit includes a first oil circuit and a second oil circuit. The first reversing valve (62) is a three-way valve. The first oil circuit is connected to the first working oil port and the working oil port of the first reversing valve (62) respectively. The second oil circuit is connected to the second working oil port and the oil tank. The first oil pump (12) and the oil tank are connected to the oil inlet and oil return port of the first reversing valve (62) respectively.

3. The hydraulic system according to claim 2, characterized in that, The second oil circuit is provided with a solenoid valve and an overflow valve in sequence in the direction extending from the second working oil port to the oil tank.

4. The hydraulic system according to claim 1, characterized in that, The auxiliary unit includes a first oil replenishment branch, which is connected to the second oil pump (11) and the second working oil port respectively.

5. The hydraulic system according to claim 4, characterized in that, The auxiliary unit includes a second oil replenishment branch, which is connected to the second oil pump (11) and the first working oil port respectively, and is used to replenish oil from the first working oil port when the heavy object rises.

6. The hydraulic system according to claim 4, characterized in that, The auxiliary unit includes an oil replenishment bypass, which connects the oil tank and the second working oil port. A one-way valve is provided on the oil replenishment bypass for replenishing oil from the second working oil port when the weight of the object decreases.

7. The hydraulic system according to claim 1, characterized in that, It also includes a detection unit for acquiring lifting load data; the control unit also includes a processor and a second reversing valve (61), the processor being connected to the detection unit, the first reversing valve (62) and the second reversing valve (61) respectively, for turning on the first reversing valve (62) or the second reversing valve (61) according to the comparison result of the lifting load data and the set value.

8. The hydraulic system according to claim 7, characterized in that, The second directional valve (61) is a four-way valve. The first working port and the second working port are respectively connected to the working port of the second directional valve (61). The first oil pump (12) and the oil tank are respectively connected to the oil inlet and oil return port of the second directional valve (61).

9. The hydraulic system according to claim 1, characterized in that, It also includes a detection unit for acquiring lifting load data; the first oil pump (12) is a constant pressure variable pump, and the execution unit (9) is a lifting variable motor; the control unit also includes a processor, which is connected to the detection unit, the first oil pump (12) and the execution unit (9) respectively, for adjusting the output flow rate and motor displacement according to the lifting load data.

10. The hydraulic system according to claim 7, characterized in that, The first directional valve (62) and the second directional valve (61) are electro-hydraulic proportional directional valves.

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