Boom operation machine and hydraulic system thereof

Abstract

The invention belongs to the technical field of operation machinery and provides a boom operation machine and a hydraulic system thereof. The system comprises a main pump, an auxiliary pump, a main boom control valve group, an auxiliary boom control valve group and a main shuttle valve. The main pump is a load-sensitive variable pump, the main arm control valve group is connected with an output oil port of the main pump, the auxiliary arm control valve group is connected with the main arm control valve group in parallel and connected to the output oil port of the main pump, the oil taking end of the main shuttle valve is connected with the main arm control valve group and the auxiliary arm control valve group, and the output end of the main shuttle valve is connected to the control end of the main pump. And the main shuttle valve is used for selecting one of the main arm control valve group and the auxiliary arm control valve group with high working oil pressure and guiding the selected high-pressure oil to the control end of the main pump. The main pump of the system can drive the fly jib to work with small pressure loss, and the oil duct drift diameter design of the fly jib control valve group only needs to meet the self flow demand of the fly jib, so that the dependence on a speed regulating valve can be eliminated, and the purpose of simplifying the system is achieved.

Description

Technical Field

[0001] This invention belongs to the field of construction machinery technology, specifically relating to a boom-operated machine and its hydraulic system. Background Technology

[0002] The main boom of a boom lift typically uses a large-displacement variable displacement main pump for independent hydraulic supply to optimize its performance and energy consumption. The auxiliary pump (with a smaller displacement than the main pump) powers the boom cylinders, swing motor, and outrigger cylinders. Due to industry regulations and pressure loss considerations, priority rules are usually established between the actuators (boom, swing, or outriggers) in the auxiliary pump circuit. When the auxiliary pump circuit is operating, the outriggers have the highest priority, followed by the boom, and finally the swing. In the hydraulic circuit, the relevant control valves are connected in series according to priority. For example, the outrigger control valve is usually located upstream of the hydraulic source, the boom control valve is connected downstream of the outrigger control valve, and the swing control valve is connected downstream of the boom control valve.

[0003] For this type of system, with multiple interconnected systems, the auxiliary boom control valve needs to serve as an oil transfer station for all actuators except the outriggers. This necessitates that the oil passage of the auxiliary boom control valve be of a large diameter. Large-diameter control valves are much more expensive than ordinary control valves. Furthermore, with such a large oil passage diameter, even a slight displacement of the valve core can cause drastic changes in the flow rate entering the auxiliary boom. This forces the auxiliary boom control valve to be paired with a speed control valve to achieve speed stability, increasing the complexity of the system. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies, the present invention provides a boom-operating machine and its hydraulic system, which aims to solve the technical problems of high cost and complex structure of hydraulic system valves in existing boom-operating machines.

[0005] To achieve the above objectives, the present invention provides a hydraulic system for boom-operated machinery. This system includes a main pump and an auxiliary pump, a main boom control valve group, an auxiliary boom control valve group, and a main shuttle valve. The main pump is a load-sensitive variable pump. The main boom control valve group is connected to the output port of the main pump. The auxiliary boom control valve group is connected in parallel with the main boom control valve group and connected to the output port of the main pump. The oil intake end of the main shuttle valve is connected to both the main boom control valve group and the auxiliary boom control valve group, and its output end is connected to the control end of the main pump. The main shuttle valve is used to select the higher working oil pressure between the main boom control valve group and the auxiliary boom control valve group and direct the selected high-pressure oil to the control end of the main pump.

[0006] In an embodiment of the present invention, the auxiliary boom control valve group includes an auxiliary boom directional valve, which is connected to the main pump, the auxiliary boom cylinder, and the return oil line. The auxiliary boom directional valve is used to selectively guide the hydraulic oil output by the main pump to one of the working chambers of the auxiliary boom cylinder, and at the same time, it is used to control the return oil of the other working chamber of the auxiliary boom cylinder. One of the oil inlet terminals of the main shuttle valve is connected to the working port of the auxiliary boom directional valve, and the working port of the auxiliary boom directional valve is used to connect to the working chamber of the auxiliary boom cylinder.

[0007] In an embodiment of the present invention, the auxiliary boom reversing valve includes a first working port and a second working port, which are respectively connected to the two working chambers of the auxiliary boom cylinder. The auxiliary boom control valve group also includes an auxiliary boom shuttle valve, whose oil intake end is connected to the first working port and the second working port respectively, and whose output end is connected to one of the oil intake ends of the main shuttle valve. The auxiliary boom shuttle valve is used to select the one with higher oil pressure between the first working port and the second working port and guide the selected high-pressure oil to the main shuttle valve.

[0008] In an embodiment of the present invention, the auxiliary boom control valve group further includes a pressure limiting valve, which is disposed between the auxiliary boom valve inlet of the auxiliary boom reversing valve and the main pump. The pressure limiting valve is used to limit the oil pressure delivered by the main pump to the auxiliary boom valve inlet of the auxiliary boom reversing valve.

[0009] In embodiments of the present invention, the pressure limiting valve is a pressure reducing valve disposed on the oil inlet of the auxiliary arm valve, or a relief valve disposed between the oil inlet of the auxiliary arm valve and the return oil circuit.

[0010] In embodiments of the present invention, the auxiliary arm directional valve is a proportional solenoid directional valve or a switching solenoid directional valve.

[0011] In an embodiment of the present invention, the two working chambers of the auxiliary boom cylinder are the rod chamber and the rodless chamber, respectively. The auxiliary boom reversing valve includes a first working port and a second working port. The first working port and the second working port are respectively connected to the rodless chamber and the rod chamber of the auxiliary boom cylinder. A one-way throttle valve is provided between the rod chamber and the second working port. The one-way throttle valve is used to unilaterally guide and reverse throttle when oil enters the rod chamber.

[0012] In an embodiment of the present invention, the hydraulic system of the boom-operating machinery further includes an auxiliary pump and an outrigger control valve assembly, wherein the outrigger control valve assembly is connected to the auxiliary pump and is used to control the extension and retraction of the outriggers of the boom-operating machinery.

[0013] In an embodiment of the present invention, the hydraulic system of the boom-operating machinery further includes a slewing control valve assembly, which is connected in series downstream of the outrigger control valve assembly and is used to control the slewing of the boom-operating machinery.

[0014] To achieve the above objectives, the present invention also provides a boom operating machine, wherein the boom operating machine includes a hydraulic system according to the boom operating machine described above.

[0015] Through the above technical solution, the hydraulic system of the boom-operating machinery provided in the embodiments of the present invention has the following beneficial effects: This system connects the auxiliary boom control valve assembly and the main boom control valve directly in parallel to the main pump's output port. Pressure selection and input control of the main pump's control terminal are achieved through the main shuttle valve. This allows the main pump to supply oil to the corresponding auxiliary or main boom with a constant flow rate, matching the load, while the main and auxiliary booms operate independently, thus reducing system energy consumption. Simultaneously, the oil output from the main pump can be directly guided to the auxiliary boom control valve assembly, reducing oil pressure loss when hydraulic oil flows to the auxiliary boom cylinder. Furthermore, this system removes the auxiliary boom control valve assembly from the auxiliary pump's oil supply circuit. The oil passage diameter of the auxiliary boom control valve assembly only needs to meet the auxiliary boom's own flow requirements, eliminating the need for a large-diameter design. This significantly reduces valve assembly procurement costs, eliminates reliance on speed control valves, simplifies the system structure, and provides better linear flow gain characteristics for the valve assembly.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a hydraulic schematic diagram of a first embodiment of the hydraulic system of a boom-operating machine according to an embodiment of the present invention; Figure 2 This is a hydraulic schematic diagram of a second embodiment of the hydraulic system of the boom-operating machinery according to an embodiment of the present invention; Figure 3 This is a hydraulic schematic diagram of a third embodiment of the hydraulic system of the boom-operating machinery according to the present invention.

[0018] Explanation of reference numerals in the attached figures 1. Main pump; 2. Main boom control valve assembly; 3. Auxiliary boom control valve assembly; 31. Auxiliary boom directional valve; P1. Auxiliary boom valve inlet; T1. Auxiliary boom valve return port; A1. First working port; B1. Second working port; 32. Auxiliary boom shuttle valve; 33. Pressure limiting valve; 331. Pressure reducing valve; 332. Relief valve; 34. One-way throttle valve; 35. Auxiliary boom cylinder; 4. Main shuttle valve; 5. Auxiliary pump; 61. Outrigger control valve assembly; 62. Rotation control valve assembly. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] The hydraulic system of the boom-operating machinery of the present invention will now be described with reference to the accompanying drawings.

[0021] Existing boom lifting machinery generally adopts a dual-pump hydraulic supply system, such as a variable displacement pump + fixed displacement pump. In this system, the main pump drives the boom and is a load-sensitive variable pump that dynamically adjusts its output displacement according to the boom's movement requirements. The auxiliary pump is a fixed displacement gear pump, which primarily supplies hydraulic oil to the outrigger drive mechanism, the jib, and the slewing mechanism.

[0022] In current system designs, the main pump's control terminal is typically connected to the main boom. However, due to operational safety regulations, the main boom and auxiliary boom of a boom-operated machine are generally not allowed to operate simultaneously. Therefore, if the auxiliary boom is connected to the main pump's output oil circuit during system design, the main pump will be in standby mode when the auxiliary boom is working and the main boom is stationary, as there is no load demand from the main boom, and the main pump cannot provide effective driving force to the auxiliary boom. Therefore, existing technical solutions typically assign the auxiliary pump to handle the oil supply for the auxiliary boom.

[0023] When the boom is supplied with oil via the auxiliary pump, in order to reduce hydraulic oil pressure loss from the auxiliary pump to the boom control valve assembly and ensure that the boom's actions have a high priority, the boom control valve assembly needs to be located as close to the auxiliary pump as possible. Therefore, existing boom control valve assemblies generally need to serve as oil circuit transfer stations for some other mechanism valve assemblies.

[0024] The auxiliary boom control valve assembly acts as a transfer station in the hydraulic circuit, necessitating a large-diameter design for its internal oil passages to meet flow requirements. Large-diameter valve assemblies are generally expensive and have poor control characteristics; even slight movements of the valve core can cause drastic changes in the incoming flow. In existing systems, to stabilize the auxiliary boom speed, an additional speed control valve must be added to the auxiliary boom control valve assembly. This not only increases component costs but also makes the entire hydraulic system more complex.

[0025] In addition, the auxiliary boom is supplied with oil by a fixed displacement pump, and its operating speed will fluctuate with the load (the speed slows down when the load increases). Its operation stability is not as good as that of the main boom. Moreover, as a high-energy-consuming actuator as the main boom, the auxiliary boom is supplied with oil by a fixed displacement pump. In many cases, the output flow of the fixed displacement pump is greater than the flow required by the load of the auxiliary boom, resulting in high energy consumption of the auxiliary boom.

[0026] In view of this, the present invention discloses a hydraulic system for boom-operated machinery, such as... Figure 1 , Figure 2 and Figure 3As shown, the hydraulic system includes a main pump 1, an auxiliary pump 5, a main boom control valve group 2, an auxiliary boom control valve group 3, and a main shuttle valve 4.

[0027] Main pump 1 is a load-sensitive variable pump and can adaptively change its displacement according to the load.

[0028] The main boom control valve group 2 is connected to the output port of the main pump 1 and is used to control the main boom to perform telescopic, luffing, and other actions.

[0029] The auxiliary boom control valve group 3 is set in parallel with the main boom control valve group 2 and connected to the output port of the main pump 1. The auxiliary boom control valve group 3 is used to control the action of the auxiliary boom cylinder.

[0030] The oil intake end of the main shuttle valve is connected to the main boom control valve group 2 and the auxiliary boom control valve group 3 respectively, and the output end is connected to the control end of the main pump 1. The main shuttle valve 4 is used to select the one with the higher working oil pressure between the main boom control valve group 2 and the auxiliary boom control valve group 3, and guide the selected high-pressure oil to the control end of the main pump 1.

[0031] This system connects the auxiliary boom control valve assembly 3 directly in parallel with the main boom control valve to the output port of the main pump 1, and uses the main shuttle valve 4 for pressure selection and input control of the main pump 1. This allows the main pump 1 to supply oil to the corresponding auxiliary boom or main boom with a constant flow rate, matching the load, thus reducing system energy consumption, even when the main boom and auxiliary boom are operating separately. Simultaneously, the oil output from the main pump can be directly guided to the auxiliary boom control valve assembly, reducing oil pressure loss when hydraulic oil flows to the auxiliary boom cylinder. Furthermore, this system removes the auxiliary boom control valve assembly 3 from the auxiliary pump 5's oil supply circuit. The oil passage diameter of the auxiliary boom control valve assembly 3 only needs to meet the auxiliary boom's own flow requirements, eliminating the need for a large-diameter design. This significantly reduces valve assembly procurement costs, eliminates reliance on speed control valves, simplifies the system structure, and improves the linear flow gain characteristics of the valve assembly.

[0032] like Figure 1 and Figure 2 As shown, in this embodiment, the auxiliary boom control valve group 3 includes an auxiliary boom directional valve 31, which is connected to the main pump 1, the auxiliary boom cylinder 35, and the return oil pipeline. The auxiliary boom directional valve 31 is used to selectively guide the hydraulic oil output from the main pump 1 to one of the working chambers of the auxiliary boom cylinder 35, and simultaneously controls the return oil to the other working chamber of the auxiliary boom cylinder 35. One of the oil inlet terminals of the main shuttle valve 4 is connected to the working port of the auxiliary boom directional valve 31, and the working port of the auxiliary boom directional valve is used to connect to the working chamber of the auxiliary boom cylinder 35.

[0033] Specifically, the auxiliary boom reversing valve 31 is provided with an auxiliary boom valve inlet P1, an auxiliary boom valve return port T1, an auxiliary boom first working port A1, and an auxiliary boom second working port B1. The auxiliary boom valve inlet P1 is used to connect to the output port of the main pump 1, the auxiliary boom valve return port T1 is used to connect to the return oil circuit, the auxiliary boom first working port A1 is used to connect to one of the working chambers of the auxiliary boom cylinder 35, and the auxiliary boom second working port B1 is used to connect to the other working chamber of the auxiliary boom cylinder 35.

[0034] The auxiliary boom directional valve 31 also has at least a first open valve position, a second open valve position, and a shut-off valve position. The first open valve position is used to selectively guide the hydraulic oil output by the main pump 1 to the rodless chamber of the auxiliary boom cylinder 35, and at the same time supply oil return to the rod chamber of the auxiliary boom cylinder 35. The second open valve position is used to selectively guide the hydraulic oil output by the main pump 1 to the rod chamber of the auxiliary boom cylinder 35, and at the same time supply oil return to the rodless chamber of the auxiliary boom cylinder 35. The shut-off valve position is used to control the auxiliary boom valve inlet P1 to be shut off, and to control the auxiliary boom first working oil port A1 and the auxiliary boom second working oil port B1 to be connected to the auxiliary boom valve return oil port T1.

[0035] The extension and retraction of the auxiliary boom cylinder 35 can be controlled by the auxiliary boom reversing valve 31.

[0036] like Figure 1 and Figure 3 As shown, in an embodiment of the present invention, the auxiliary boom directional valve 31 can be a proportional solenoid directional valve. By controlling the proportional conduction of the auxiliary boom directional valve 31, the speed control of the auxiliary boom cylinder can be achieved. Of course, the auxiliary boom directional valve 31 can also be a switching solenoid directional valve that only controls the on / off state and conduction direction.

[0037] In this embodiment, the working oil pressure of the auxiliary boom control valve group 3 refers to the oil pressure in the oil inlet of the cylinder when the auxiliary boom cylinder 35 extends or retracts, and the oil pressure in the oil inlet of the cylinder is the same as the oil pressure of the corresponding auxiliary boom working port.

[0038] In order to achieve pressure tapping of the working oil pressure of the auxiliary boom control valve group 3, such as Figure 1 and Figure 2 As shown, in this embodiment, the auxiliary boom control valve group 3 may further include an auxiliary boom shuttle valve 32. The two oil intake ends of the auxiliary boom shuttle valve 32 are respectively connected to the rod chamber working oil circuit and the rodless chamber working oil circuit of the auxiliary boom cylinder 35. In other words, the oil intake ends of the auxiliary boom shuttle valve 32 are respectively connected to the first working oil port A1 and the second working oil port B1.

[0039] The output end of the auxiliary boom shuttle valve 32 is connected to one of the oil intake ends of the main shuttle valve 4. When oil enters the rodless chamber of the auxiliary boom cylinder 35, the main boom is in a stationary state. The auxiliary boom shuttle valve 32 selects the hydraulic oil in the working oil circuit of the rodless chamber and directs the hydraulic oil to the control end of the main pump 1 through the main shuttle valve 4. Similarly, when oil enters the rod chamber of the auxiliary boom cylinder 35, the main boom is in a stationary state. The auxiliary boom shuttle valve 32 selects the hydraulic oil in the working oil circuit of the rod chamber and directs the hydraulic oil to the control end of the main pump 1 through the main shuttle valve 4.

[0040] like Figure 1 and Figure 2 As shown, in this embodiment, in order to ensure that the input of the boom shuttle valve 32 is low pressure when the boom stops working, a one-way hydraulic lock can be set in the working oil circuit of the rod chamber and the working oil circuit of the rodless chamber of the boom cylinder 35, and the boom shuttle valve 32 is connected to the working oil circuit between the one-way hydraulic lock and the boom reversing valve 31.

[0041] like Figure 1 and Figure 2 As shown, in this embodiment, when the main shuttle valve takes pressure from the main boom control valve group 2, the main boom control valve group 2 can adopt a similar arrangement to the auxiliary boom control valve group 3.

[0042] The jib of a boom lift is typically located at the end of the main boom and is primarily used to extend the main boom's working range or change its working angle. During operation, the main boom bears not only its own weight but also the weight of the jib's load; therefore, the load on the main boom is significantly greater than that on the jib. Due to the different loads, the hydraulic cylinder dimensions and valve manifold diameters of the main boom and jib differ. For example, the cylinder diameter of the main boom cylinder is generally larger than that of the jib cylinder.

[0043] To ensure operational safety, the maximum load working pressure of the auxiliary boom cylinder 35 needs to be limited to less than the maximum load working pressure of the main boom cylinder. This is because when the auxiliary boom carries an excessive load, the main boom cylinder needs to bear a greater load, which may cause damage to the main boom cylinder and its connected hydraulic components.

[0044] To limit the maximum load of the auxiliary boom cylinder 35, in this embodiment, the auxiliary boom control valve assembly 3 may further include a pressure limiting valve 33. The pressure limiting valve 33 is disposed between the auxiliary boom valve inlet P1 of the auxiliary boom directional valve 31 and the main pump 1. Further, the pressure limiting valve 33 may be disposed at the auxiliary boom valve inlet P1 of the auxiliary boom directional valve 31. Through the pressure limiting valve 33, the maximum inlet pressure of the auxiliary boom control valve assembly 3 can be limited to a range lower than the maximum load working pressure of the main boom cylinder.

[0045] like Figure 1As shown, in this embodiment, the pressure control valve can be a pressure reducing valve 331 located between the oil inlet of the auxiliary boom directional valve 31 and the main pump 1. Through the pressure reducing valve 331, the maximum working oil pressure of the auxiliary boom control valve group 3 can be controlled to be less than the maximum working oil pressure of the main boom control valve group 2.

[0046] The working principle of this system will be described below by combining the cooperation process between the pressure reducing valve and the main pump.

[0047] The oil pressure input to the control terminal of the load-sensitive variable pump (hereinafter referred to as the load-sensitive pump) is Pi. Pi is the oil pressure of the higher working oil pressure among the main boom control valve group 2 and the auxiliary boom control valve group 3 selected by the main shuttle valve 4. The magnitude of Pi is determined by the load. The load-sensitive pump compares Pi with its own output oil pressure Po. When Po - Pi = preset oil pressure difference Δp, the load-sensitive pump maintains the current displacement; when Po - Pi > Δp, the load-sensitive pump reduces the displacement; when Po - Pi < Δp, the load-sensitive pump increases the displacement.

[0048] The preset oil pressure difference Δp parameter in main pump 1 is generally designed to accommodate the heavy load conditions of the main boom. That is, by setting an appropriate Δp parameter, the main boom can operate smoothly at a more suitable speed.

[0049] Taking one case as an example, for the luffing of the main boom, Δp can be designed to be 2 MPa. In the initial case, assuming that the oil pressure Po at the output port of the main pump 1 is 20 MPa, and the working oil pressure of the main boom luffing cylinder is 18 MPa (that is, the input pressure Pi at the control end = 18 MPa), Po - Pi = Δp (2 MPa). The pressure difference of 2 MPa can ensure that the flow rate of the main pump 1 to the main boom luffing cylinder is appropriate and constant, and the main boom luffing cylinder is in a state of uniform motion with appropriate speed.

[0050] When the working load of the boom luffing cylinder increases during operation, the pressure Pi delivered to the control end of the main pump 1 increases, causing Po-Pi < Δp in the main pump 1. The displacement adjustment mechanism inside the main pump 1 will control the main pump 1 to adjust adaptively, so that Po rises until the difference between Po-Pi is equal to 2 MPa again.

[0051] Although the displacement of the main pump 1 changes, the increase in the working oil pressure of the main boom luffing cylinder also increases the resistance of the main pump 1 flow phase main boom control valve group 2. Ultimately, the pressure difference between the two is still 2 MPa. The flow rate generated by the 2 MPa pressure difference is almost the same as before. The main boom cylinder is in a constant flow working state, and the working flow rate of the main boom cylinder is not affected by the load.

[0052] However, the auxiliary boom's cylinder specifications and valve assembly design differ from the main boom's. The Δp parameter, originally designed to match the main boom's optimal operating conditions, may not be well-suited to the auxiliary boom. In other words, using a flow rate generated by a 2 MPa pressure differential to supply oil to the auxiliary boom may cause its movement to be too fast or too slow, resulting in poor operational stability.

[0053] In this embodiment, the pressure control valve is set as a pressure reducing valve 331. In addition to suppressing the maximum working pressure of the auxiliary arm control valve group 3, the pressure reducing valve 331 can also reduce the pressure difference between the input end of the auxiliary arm control valve group 3 and the output end of the arm control valve group.

[0054] Assuming the working oil pressure at the output of the auxiliary boom control valve group 3 is 8 MPa, the main pump 1 achieves a pressure output of 10 MPa through adaptive displacement adjustment. When the 10 MPa pressure oil reaches the pressure reducing valve 331, the pressure reducing valve 331 will reduce the pressure, making the oil pressure at the input of the auxiliary boom control valve group 3 9 MPa, a reduction of 1 MPa. Ultimately, the flow rate of the auxiliary boom reversing valve 31 is the flow rate generated by the 1 MPa pressure difference. Compared to the original flow rate generated by the 2 MPa pressure difference, the movement speed of the auxiliary boom is significantly reduced. By reducing the speed of the auxiliary boom, overspeed operation of the auxiliary boom under the drive of the main pump 1 can be avoided, ensuring smooth operation of the auxiliary boom.

[0055] It should be noted that the input end of the auxiliary boom control valve group 3 refers to the position of the auxiliary boom valve inlet P1 of the auxiliary boom directional valve 31, and the output end of the boom control valve group refers to the position of the working oil port of the auxiliary boom directional valve 31. The oil pressure at this position is equal to the working oil pressure of the auxiliary boom control valve group 3.

[0056] Of course, such as Figure 2 As shown, in this embodiment, the pressure limiting valve 33 can also be a relief valve 332 disposed between the oil inlet and the return oil circuit of the auxiliary boom directional valve 31. When the input oil pressure of the auxiliary boom directional valve 31 exceeds the opening setting value of the relief valve 332, the relief valve 332 will overflow the oil to ensure that the working pressure of the auxiliary boom is always within the setting range of the relief valve 332.

[0057] like Figure 1 and Figure 2 As shown, in this embodiment, the two working chambers of the auxiliary boom cylinder 35 are the rod chamber and the rodless chamber, respectively. The auxiliary boom reversing valve 31 includes a first working port A1 and a second working port B1. The first working port A1 and the second working port B1 are respectively connected to the rodless chamber and the rod chamber of the auxiliary boom cylinder 35. A one-way throttle valve 34 is provided between the rod chamber and the second working port B1. The one-way throttle valve 34 is used to unilaterally open and reverse throttle when oil enters the rod chamber.

[0058] The one-way throttle valve 34 is composed of a one-way valve and a throttle valve connected in parallel. The one-way valve is configured to open when hydraulic oil flows from the boom reversing valve 31 into the rod chamber of the cylinder and close in the reverse direction. When not in use, the boom is generally folded onto the main boom. Therefore, when the boom cylinder 35 retracts, it indicates that the boom cylinder 35 has completed its operation and needs to be reset and folded. Controlling the oil flow into the rod chamber of the boom cylinder 35 allows for low-resistance and rapid entry of hydraulic oil into the rod chamber via the one-way valve, enabling the boom cylinder 35 to retract and fold quickly, improving work efficiency. When the boom cylinder 35 extends, sometimes it is necessary to fine-tune the extension length or luffing angle of the boom, or sometimes it is necessary to ensure that the boom cylinder 35 extends slowly to guarantee smooth movement. Therefore, a throttle valve is installed to slow down the extension rate of the boom cylinder 35.

[0059] Understandably, when the jib is carrying a load, it will not perform luffing or telescopic movements. The luffing and telescopic movements of the entire boom are controlled by the main boom's luffing cylinder. The jib needs to be adjusted to the correct angle or length before it can carry a load.

[0060] In this embodiment, the hydraulic system of the boom-operated machinery also includes an auxiliary pump 5 and an outrigger control valve assembly 61. The outrigger control valve assembly 61 is connected to the auxiliary pump 5 and is used to control the extension and retraction of the outriggers of the boom-operated machinery. The auxiliary pump 5 is a fixed-displacement pump and is dedicated to supplying oil to the outrigger control mechanism, slewing mechanism, etc. of the machinery. By setting the auxiliary boom as a fixed-displacement pump, the system cost can be reduced.

[0061] To achieve the system's outrigger priority function, such as Figure 1 and Figure 2 As shown, the outrigger control valve assembly 61 is preferentially connected in series with the auxiliary pump 5, and other auxiliary actuators are connected in series downstream of the outrigger control valve assembly 61. Oil is supplied to the outrigger control valve assembly 61 through the auxiliary boom, which can control the extension and retraction of the outriggers of the boom-operated machinery. like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, other auxiliary actuators may include a slewing actuator, which includes a slewing control valve assembly 62. The slewing control valve assembly 62 is connected to the working port of the outrigger control valve assembly 61 and is used to control the slewing of the boom working machinery. The outrigger control valve assembly 61 is used to control the hydraulic oil of the auxiliary pump 5 to selectively flow to the slewing control valve assembly 62 or the slewing motor.

[0062] To achieve the above objectives, the present invention also provides a boom-operating machine, wherein the boom-operating machine includes a hydraulic system according to the boom-operating machine described above. The boom-operating machine can be a boom-type truck-mounted crane, a boom-type aerial work platform, a boom-type fire truck, etc. Since the machine adopts all the technical solutions of the above embodiments, it at least possesses the beneficial effects brought by the above embodiments, and will not be repeated here.

[0063] In the description of this invention, it should be understood that 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 indicated technical features. 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.

[0064] 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, an electrical connection, or a connection that allows communication between them; 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.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] Although embodiments of the present invention have been described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydraulic system for boom-operated machinery, characterized in that, The hydraulic system of the boom-operating machinery includes: The main pump (1) and the auxiliary pump (5) are a load-sensitive variable pump. The main boom control valve group (2) is connected to the output port of the main pump (1); The auxiliary boom control valve group (3) is arranged in parallel with the main boom control valve group (2) and connected to the output port of the main pump (1); The main shuttle valve (4) has its oil intake end connected to the main boom control valve group (2) and the auxiliary boom control valve group (3) respectively, and its output end connected to the control end of the main pump (1). The main shuttle valve (4) is used to select the one with the higher working oil pressure between the main boom control valve group (2) and the auxiliary boom control valve group (3), and guide the selected high-pressure oil to the control end of the main pump (1).

2. The hydraulic system of the boom-operating machinery according to claim 1, characterized in that, The auxiliary boom control valve group (3) includes an auxiliary boom reversing valve (31). The auxiliary boom reversing valve (31) is connected to the main pump (1), the auxiliary boom cylinder (35), and the return oil pipeline. The auxiliary boom reversing valve (31) is used to select and guide the hydraulic oil output by the main pump (1) to one of the working chambers of the auxiliary boom cylinder (35), and at the same time, it is used to control the return oil of the other working chamber of the auxiliary boom cylinder (35). One of the oil intake ends of the main shuttle valve (4) is connected to the working oil port of the auxiliary boom reversing valve (31). The working oil port of the auxiliary boom reversing valve (31) is used to connect with the working chamber of the auxiliary boom cylinder (35).

3. The hydraulic system of the boom-operating machinery according to claim 2, characterized in that, The auxiliary boom reversing valve (31) includes a first working port (A1) and a second working port (B1). The first working port (A1) and the second working port (B1) are respectively connected to the two working chambers of the auxiliary boom cylinder (35). The auxiliary boom control valve group (3) also includes an auxiliary boom shuttle valve (32). The oil intake end of the auxiliary boom shuttle valve (32) is connected to the first working port (A1) and the second working port (B1) respectively. The output end of the auxiliary boom shuttle valve (32) is connected to one of the oil intake ends of the main shuttle valve (4). The auxiliary boom shuttle valve (32) is used to select the one with higher oil pressure between the first working port (A1) and the second working port (B1) and guide the selected high-pressure oil to the main shuttle valve (4).

4. The hydraulic system of the boom-operating machinery according to claim 2, characterized in that, The auxiliary boom control valve group (3) also includes a pressure limiting valve (33), which is located between the auxiliary boom valve inlet (P1) of the auxiliary boom reversing valve (31) and the main pump (1). The pressure limiting valve (33) is used to limit the oil pressure delivered by the main pump (1) to the auxiliary boom valve inlet (P1) of the auxiliary boom reversing valve (31).

5. The hydraulic system of the boom-operating machinery according to claim 4, characterized in that, The pressure limiting valve (33) is a pressure reducing valve (331) installed on the oil inlet (P1) of the auxiliary arm valve, or the pressure limiting valve (33) is an overflow valve (332) installed between the oil inlet (P1) of the auxiliary arm valve and the return oil circuit.

6. The hydraulic system of the boom-operating machinery according to claim 2, characterized in that, The auxiliary arm directional valve (31) is a proportional solenoid directional valve or a switch solenoid directional valve.

7. The hydraulic system of the boom-operating machinery according to claim 2, characterized in that, The two working chambers of the auxiliary boom cylinder (35) are the rod chamber and the rodless chamber, respectively. The auxiliary boom reversing valve (31) includes a first working port (A1) and a second working port (B1). The first working port (A1) and the second working port (B1) are respectively connected to the rodless chamber and the rod chamber of the auxiliary boom cylinder (35). A one-way throttle valve (34) is provided between the rod chamber and the second working port (B1). The one-way throttle valve (34) is used to unilaterally open and reverse throttle when oil enters the rod chamber.

8. The hydraulic system of the boom-operating machinery according to any one of claims 1 to 7, characterized in that, The hydraulic system of the boom-operating machinery also includes a leg control valve assembly (61), which is connected to the auxiliary pump (5) and is used to control the extension and retraction of the outriggers of the boom-operating machinery.

9. The hydraulic system of the boom-operating machinery according to claim 8, characterized in that, The hydraulic system of the boom-operating machinery also includes a slewing control valve assembly (62), which is connected in series downstream of the outrigger control valve assembly (61) and is used to control the slewing of the boom-operating machinery.

10. A boom-operated machine, characterized in that, Includes the hydraulic system of the boom-operating machinery according to any one of claims 1 to 9.

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