Pumping hydraulic system and concrete pumping machinery

Abstract

The present invention provides a pumping hydraulic system and a concrete pumping machine. The pumping hydraulic system includes two pumping cylinders connected in series, a main oil pump, a main reversing valve, and a high-low pressure switching valve. The main oil pump pumps hydraulic oil to the pumping hydraulic system through a pumping oil circuit. The main reversing valve is arranged on the pumping oil circuit and controls the telescopic movement of the pumping cylinders. The high-low pressure switching valve is arranged on the oil supply circuit of the main reversing valve. The valve core of the high-low pressure switching valve can be switched between a first working position and a second working position, so that the hydraulic oil pumped by the main oil pump enters the rod chamber or the rodless chamber of one of the pumping cylinders through the high-low pressure switching valve. In the pumping hydraulic system of the present invention, the high-pressure and low-pressure pumping states of the pumping cylinders can be realized by the cooperation of a high-low pressure switching valve and a main reversing valve, which simplifies the structure and improves the pumping efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete pumping, and particularly relates to a pumping hydraulic system and a concrete pumping machine. Background Art

[0002] Concrete pumping equipment is used to transport concrete and is widely used in modern engineering construction. Generally, concrete pumping equipment realizes the suction and discharge of concrete through the reciprocating motion of two concrete pistons in the concrete cylinders, and the hydraulic system that controls and drives the action of the concrete pistons is called a pumping hydraulic system. In pumping equipment, to improve the equipment's adaptability to working conditions, there are two connection methods for the pumping cylinders, and the corresponding working states are called high-pressure pumping and low-pressure pumping in the industry. In high-pressure pumping, pressure oil enters the rodless chamber of the pumping cylinder. Due to the large acting area, the concrete conveying pressure is high, but the speed is slow. In low-pressure pumping, pressure oil enters the rod chamber of the pumping cylinder, with a small acting area but a fast speed. In the prior art, a pumping hydraulic system with a high-low pressure conversion function uses two reversing valves to achieve high-low pressure conversion, and the two main reversing valves are in a parallel state. Since it is necessary to pass through the neutral position during each reversing process, before the reversing valve reaches the neutral position, the system pressure needs to be unloaded through an electromagnetic overflow valve. After the reversing valve reaches the reversing position, the electromagnetic overflow valve needs to build pressure again, and the reversing process is complex. Since the time for the reversing valve to return to the neutral position and the time for reversing to the other side are different under different working conditions, it is very difficult to achieve complete matching. When the matching is not good, impact will occur, resulting in an unstable situation, or the reversing process needs to be extended, but this will reduce the system efficiency. Summary of the Invention

[0003] The main object of the present invention is to provide a pumping hydraulic system and a concrete pumping machine, aiming to solve the technical problems of complex and unstable reversing process of the pumping hydraulic system with a high-low pressure conversion function in the prior art.

[0004] To achieve the above object, the present invention provides a pumping hydraulic system, including two pumping cylinders connected in series. The pumping hydraulic system includes:

[0005] A main oil pump that pumps hydraulic oil to the pumping hydraulic system through a pumping oil circuit;

[0006] A main reversing valve provided on the pumping oil circuit to control the telescopic actions of the first pumping cylinder and the second pumping cylinder; and

[0007] A high-low pressure switching valve provided on the oil supply circuit of the main reversing valve. The spool of the high-low pressure switching valve can be switched between a first working position and a second working position, so that the hydraulic oil pumped by the main oil pump enters the rod chamber or the rodless chamber of one of the pumping cylinders through the high-low pressure switching valve.

[0008] In an embodiment of the present invention, the main reversing valve includes a first hydraulic reversing valve and a first pilot solenoid valve for controlling the switching of the first hydraulic reversing valve between a first switching position and a second switching position. The first hydraulic reversing valve includes a main oil inlet and a main oil return port on one side, and a first oil supply port and a second oil supply port on the other side.

[0009] In the first switching position, the first working oil port is communicated with the main oil inlet and the second working oil port is communicated with the main oil return port.

[0010] In the second switching position, the first working oil port is communicated with the main oil return port and the second working oil port is communicated with the main oil inlet.

[0011] In an embodiment of the present invention, the first hydraulic reversing valve further includes an intermediate cut-off position in which the main oil inlet is communicated with the main oil return port and both the first oil supply port and the second oil supply port are cut off.

[0012] In an embodiment of the present invention, the high-low pressure switching valve is a two-position six-way electro-hydraulic reversing valve.

[0013] In an embodiment of the present invention, the high-low pressure switching valve includes a second hydraulic reversing valve. The first working oil port and the second working oil port on the first side of the second hydraulic reversing valve are respectively communicated with the rod chambers of two pumping cylinders, and the third working oil port and the fourth working oil port on the first side are respectively communicated with the rodless chambers of the two pumping cylinders. The first working oil port and the second working oil port on the second side of the second hydraulic reversing valve are respectively communicated with the first oil supply port and the second oil supply port of the main reversing valve.

[0014] In an embodiment of the present invention, the high-low pressure reversing valve further includes a second pilot solenoid valve for controlling the switching of the second hydraulic reversing valve between a first working position and a second working position, wherein:

[0015] In the first working position, the third working oil port and the fourth working oil port on the first side are communicated, the first working oil port on the first side is communicated with the first working oil port on the second side, and the second working oil port on the first side is communicated with the second working oil port on the second side.

[0016] In the second working position, the first working oil port and the second working oil port on the first side are communicated, the third working oil port on the first side is communicated with the first working oil port on the second side, and the fourth working oil port on the first side is communicated with the second working oil port on the second side.

[0017] In an embodiment of the present invention, the second pilot solenoid valve is a two-position four-way solenoid valve. The second pilot solenoid valve includes an electromagnet for controlling the switching between a first position and a second position. The second pilot solenoid valve includes a third oil supply port, a fourth oil supply port, a first oil inlet and a first oil return port. The third oil supply port is communicated with the cavity where the second working position of the second hydraulic reversing valve is located.

[0018] When in the first position, the second hydraulic directional control valve is unloaded through the third oil supply port of the electromagnetic directional control valve;

[0019] When in the second position, the hydraulic oil of the external control oil circuit enters the second hydraulic directional control valve through the first oil inlet.

[0020] In an embodiment of the present invention, the main directional control valve and the high-low pressure switching valve are an integrated valve group structure, and the first pilot electromagnetic valve and the second pilot electromagnetic valve are both integrated on the valve body or the end cover.

[0021] In an embodiment of the present invention, a pressure control device is further provided on the oil inlet circuit of the pumping hydraulic system.

[0022] In an embodiment of the present invention, a concrete pumping machine is further proposed, including the pumping hydraulic system as above.

[0023] Through the above technical solutions, the pumping hydraulic system provided by the embodiments of the present invention has the following beneficial effects:

[0024] Compared with the situation in the prior art where the high and low pressures are controlled by one directional control valve respectively, in this application, a high-low pressure switching valve is arranged on the oil supply circuit of the main directional control valve. The main directional control valve is used to control the telescopic commutation actions of two pumping oil pumps, and the high-low pressure switching valve is used to selectively pump the pressurized oil pumped by the main oil pump to the rod chamber or the non-rod chamber of two series-connected pumping cylinders; when pumping to the rod chamber of one of the pumping cylinders, since the effective area of the rod chamber is smaller than that of the non-rod chamber, the thrust of the other pumping cylinder is smaller, but the speed is faster, so the low-pressure pumping state can be realized; when pumping to the non-rod chamber of one of the pumping cylinders, at this time the effective area is larger and the thrust is larger, realizing the high-pressure pumping state of the pumping cylinder. This high-low pressure switching process has a simple structure, omits the cumbersome middle position unloading, the commutation process is more stable, and the efficiency of the entire hydraulic pumping system is improved.

[0025] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings are used to provide an understanding of the present invention and constitute a part of the specification, and are used to explain the present invention together with the following specific implementation manners, but do not constitute a limitation to the present invention. In the drawings:

[0027] Figure 1 is a schematic hydraulic structure diagram of a pumping hydraulic system in an embodiment of the present invention;

[0028] Figure 2 is a schematic diagram of an integrated valve group structure of a main directional control valve and a high-low pressure switching valve in a pumping hydraulic system in an embodiment of the present invention.

[0029] Description of the Reference Numerals

[0030]

[0031] Detailed Embodiments

[0032] The following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.

[0033] The following describes a pumping hydraulic system according to the present invention with reference to the accompanying drawings.

[0034] As Figure 1 shown, in an embodiment of the present invention, a pumping hydraulic system is provided, which includes a first pumping cylinder 40 and a second pumping cylinder 50 connected in series. The pumping hydraulic system includes:

[0035] A main oil pump 10 that pumps hydraulic oil to the pumping hydraulic system through a pumping oil circuit L1;

[0036] A main reversing valve 21 disposed on the pumping oil circuit L1 and controlling the telescopic movements of the first pumping cylinder 40 and the second pumping cylinder 50; and

[0037] A high-low pressure switching valve 22 disposed on the oil supply circuit L2 of the main reversing valve 21. The spool of the high-low pressure switching valve 22 can be switched between a first working position and a second working position, so that the hydraulic oil pumped by the main oil pump 10 enters the rod chamber or the non-rod chamber of the first pumping cylinder 40 and the second pumping cylinder 50 through the high-low pressure switching valve 22.

[0038] For example, as Figure 1 shown, when the main oil pump 10 pumps pressure oil to the rod chamber of the first pumping cylinder 40, the non-rod chamber of the first pumping cylinder 40 returns oil. Since the two pumping cylinders are connected in series, the non-rod chamber of the second pumping cylinder 50 is filled with oil, and then the telescopic rod of the second pumping cylinder 50 is extended; at this time, since the pressure oil enters from the rod chamber of the first pumping cylinder 40, and the effective area of the rod chamber is smaller than that of the non-rod chamber, the thrust of the pressure oil is smaller at this time, that is, the second pumping cylinder 50 generates a smaller thrust on the outside under the action of the pressure oil, but the speed is fast, so that the low-pressure pumping state can be realized. On the contrary, when the main oil pump 10 pumps pressure oil to the non-rod chamber of the second pumping cylinder 50, the telescopic rod of the second pumping cylinder 50 is extended. At this time, the effective area of the non-rod chamber is larger, and the thrust generated by the pressure oil is larger, so that the high-pressure pumping state of the pumping cylinder is realized. The high-low pressure switching process of the present application has a simple structure, omits the cumbersome neutral unloading, the commutation process is more stable, and the efficiency of the entire hydraulic pumping system is improved.

[0039] In an embodiment of the present invention, the main reversing valve 21 includes a first hydraulic reversing valve 211 and a first pilot solenoid valve 212 for controlling the switching of the first hydraulic reversing valve 211 between a first switching position and a second switching position. The first hydraulic reversing valve 211 includes a main oil inlet P1 and a main oil return port T1 located on one side, and a first oil supply port A5 and a second oil supply port B5 located on the other side. When in the first switching position, the first working oil port is communicated with the main oil inlet P1 and the second working oil port is communicated with the main oil return port T1. When in the second switching position, the first working oil port is communicated with the main oil return port T1 and the second working oil port is communicated with the main oil inlet P1.

[0040] Moreover, the first hydraulic reversing valve 211 further includes an intermediate cut-off position where the main oil inlet P1 is communicated with the main oil return port T1 and both the first oil supply port A5 and the second oil supply port B5 are cut off. That is to say, when the first hydraulic reversing valve 211 is reversing, the valve core automatically passes through an unloading position at the intermediate cut-off position, and the reversing impact is very small.

[0041] Specifically, in the working condition where the first hydraulic reversing valve 211 is used for reversing, when the first hydraulic reversing valve 211 is in the first switching position on the left side, the pressure oil pumped by the main oil pump 10 enters the first oil supply port A5 and then enters the rodless cavity of the first pumping cylinder 40 or the rodless cavity of the second pumping cylinder 50 through the second hydraulic reversing valve 221 (depending on the valve core position of the second hydraulic reversing valve 221). The piston rod of the first pumping cylinder 40 retracts (or the piston rod of the second pumping cylinder 50 extends), and the piston rod of the second pumping cylinder 50 extends (or the piston rod of the first pumping cylinder 40 retracts). When the first hydraulic reversing valve 211 is in the second switching position on the right side, the pressure oil pumped by the main oil pump 10 enters the second oil supply port B5 and then enters the rodless cavity of the second pumping cylinder 50 or the rodless cavity of the first pumping cylinder 40 through the second hydraulic reversing valve 221 (depending on the valve core position of the second hydraulic reversing valve 221). The piston rod of the second pumping cylinder 50 retracts (or the piston rod of the first pumping cylinder 40 extends), and the piston rod of the first pumping cylinder 40 extends (or the piston rod of the second pumping cylinder 50 retracts). In this way, the reciprocating motion of the pumping cylinder is realized.

[0042] When the first hydraulic reversing valve 211 is in the intermediate cut-off position, the pressure oil of the main oil pump 10 flows back to the fuel tank 60 through the main oil inlet P1 and the main oil return port T1, realizing system unloading.

[0043] Further, the first pilot solenoid valve 212 of the present application is a three-position four-way solenoid valve. The fifth oil supply port A6 and the sixth oil supply port B6 of the first pilot solenoid valve 212 are respectively communicated with the main oil inlet P1 and the main oil return port T1 of the first hydraulic directional control valve 211. The second oil inlet P3 and the second oil return port T3 of the first pilot solenoid valve 212 are respectively communicated with an external control oil circuit and the oil tank 60. Both ends of the first hydraulic directional control valve 211 are respectively provided with a first control chamber. The two first control chambers on the left and right sides are respectively communicated with the fifth oil supply port A6 and the sixth oil supply port B6 of the first pilot solenoid valve 212. Two electromagnets for controlling the switching between the left position, the middle position and the right position are arranged at the left and right ends of the first pilot solenoid valve 212.

[0044] To more clearly understand the switching principle of the first hydraulic directional control valve 211, the following details the position switching process of the first pilot solenoid valve 212 controlling the first hydraulic directional control valve 211:

[0045] When the first pilot solenoid valve 212 is in the left position, the sixth oil supply port B6 is communicated with the second oil inlet P3. The pressure oil in the first control chamber on the left side of the first hydraulic directional control valve 211 is unloaded through the first pilot solenoid valve 212. At this time, there is no pressure oil in the first control chamber on the left side, and pressure oil is introduced into the first control chamber on the right side. Then, the first hydraulic directional control valve 211 is controlled to switch to the first switching position on the left side.

[0046] When the first pilot solenoid valve 212 is in the middle position, both the fifth oil supply port A6 and the sixth oil supply port B6 are communicated with the second oil return port T3. At this time, the pressure oil in the first control chambers on both the left and right sides is unloaded through the first pilot solenoid valve 212, so that the first hydraulic directional control valve 211 is in the middle cut-off position.

[0047] When the first pilot solenoid valve 212 is in the right position, the fifth oil supply port A6 is communicated with the second oil inlet P3. Pressure oil is introduced into the first control chamber on the left side of the first hydraulic directional control valve 211, and the pressure oil in the first control chamber on the right side is unloaded through the first pilot solenoid valve 212. At this time, there is no pressure oil in the first control chamber on the right side. Then, the first hydraulic directional control valve 211 is controlled to switch to the second switching position on the right side.

[0048] As Figure 1 shown, the high-low pressure switching valve 22 of the present application is a two-position six-way electro-hydraulic directional control valve.

[0049] In an embodiment of the present invention, the high-low pressure switching valve 22 includes a second hydraulic reversing valve 221. The first working oil port A1 and the first-side second working oil port B1 of the second hydraulic reversing valve 221 are respectively communicated with the rod chambers of the first pumping oil cylinder 40 and the second pumping oil cylinder 50. The first-side third working oil port A2 and the first-side fourth working oil port B2 are respectively communicated with the rodless chambers of the first pumping oil cylinder 40 and the second pumping oil cylinder 50. The second-side first working oil port A3 and the second-side second working oil port B3 of the second hydraulic reversing valve 221 are respectively communicated with the first oil supply port A5 and the second oil supply port B5 of the main reversing valve 21.

[0050] The second hydraulic reversing valve 221 is used to switch the working state of the pumping hydraulic system. When the second hydraulic reversing valve 221 is in the position as Figure 1 shown, the pressurized oil pumped by the main oil pump 10 enters the rod chamber of the first pumping oil cylinder 40 or the second pumping oil cylinder 50. The rodless chambers of the first pumping oil cylinder 40 and the second pumping oil cylinder 50 are communicated through the second hydraulic reversing valve 221. At this time, whether the rod chamber of the first pumping oil cylinder 40 is filled with oil or the rod chamber of the second pumping oil cylinder 50 is filled with oil, since the effective area of the rod chamber is small, the thrust of the pumping oil cylinder is small, but the action speed is fast. This working state is called the low-pressure pumping state in the industry. When the second pilot solenoid valve 222 is energized, the second hydraulic reversing valve 221 switches to the second working position on the right. At this time, the pressurized oil pumped by the main oil pump 10 enters the rodless chamber of the second pumping oil cylinder 50 or the first pumping oil cylinder 40 through the second hydraulic reversing valve 221. The rod chambers of the first pumping oil cylinder 40 and the second pumping oil cylinder 50 are communicated through the second hydraulic reversing valve 221. Since the effective area of the rodless chamber is large, the thrust of the pumping oil cylinder is large, but the speed is slow. This working state is called the high-pressure pumping state in the industry. The present application can achieve the purpose of high-low pressure switching through a single second hydraulic reversing valve 221, improving the pumping efficiency of the entire pumping hydraulic system.

[0051] To better achieve the switching of the spool position of the second hydraulic directional control valve 221, the high-low pressure directional control valve further includes a second pilot solenoid valve 222 for controlling the switching of the second hydraulic directional control valve 221 between the first working position and the second working position. Among them, when in the first working position, the third working oil port A2 on the first side and the fourth working oil port B2 on the first side are communicated, and the first working oil port A1 on the first side and the first working oil port A3 on the second side are communicated, and the second working oil port B1 on the first side and the second working oil port B3 on the second side are communicated. At this time, the rodless cavity of the first pumping cylinder 40 and the rodless cavity of the second pumping cylinder 50 are communicated, and the rodless cavity of the first pumping cylinder 40 or the second pumping cylinder 50 is supplied with oil. When in the second working position, the first working oil port A1 on the first side and the second working oil port B1 on the first side are communicated, the third working oil port A2 on the first side and the first working oil port A3 on the second side are communicated, and the fourth working oil port B2 on the first side and the second working oil port B3 on the second side are communicated. At this time, the rodless cavity of the second pumping cylinder 50 or the first pumping cylinder 40 is supplied with oil, and the rodless cavity of the first pumping cylinder 40 or the second pumping cylinder 50 is supplied with oil. Specifically, whether the oil enters from the first pumping cylinder 40 or the second pumping cylinder 50 is determined according to the switching position of the first hydraulic directional control valve 211 described above.

[0052] In the embodiment of the present application, as Figure 1 and Figure 2 shown, the second pilot solenoid valve 222 is a two-position four-way solenoid valve. The second pilot solenoid valve 222 includes an electromagnet for controlling the switching between the first position and the second position. The second pilot solenoid valve 222 includes a third oil supply port A4, a fourth oil supply port B4, a first oil inlet P2, and a first oil return port T2. The third oil supply port A4 is communicated with the cavity where the second working position of the second hydraulic directional control valve 221 is located, and there are only three effective working oil ports of the second pilot solenoid valve 222: the third oil supply port A4, the first oil inlet P2, and the first oil return port T2. When the spool of the second pilot solenoid valve 222 is in the first position, the second hydraulic directional control valve 221 is unloaded through the third oil supply port A4 of the solenoid directional control valve; when the spool of the second pilot solenoid valve 222 is in the second position, the hydraulic oil of the external control oil circuit enters the second hydraulic directional control valve 221 through the first oil inlet P2.

[0053] Specifically, a second elastic buffer 72 is provided at the left end of the second hydraulic directional control valve 221. The cavity where the second working position of the second hydraulic directional control valve 221 is located is a control cavity, and the control cavity is communicated with the third oil supply port A4 of the second pilot solenoid valve 222. When the electromagnet on the second pilot solenoid valve 222 loses power, the spring of the second pilot solenoid valve 222 pushes the spool of the second pilot solenoid valve 222 to act. When the second pilot solenoid valve 222 is in the first position on the left side, the pressure oil in the control cavity of the second hydraulic directional control valve 221 is unloaded through the second pilot solenoid valve 222, and there is no pressure oil in the control cavity. At this time, the second elastic buffer 72 pushes the spool of the second hydraulic directional control valve 221 to act, so that the second hydraulic directional control valve 221 is switched to the first working position on the left side. When the electromagnet on the second pilot solenoid valve 222 is powered on, the electromagnet overcomes the elastic force of the second pilot solenoid valve 222 and pushes the spool of the second pilot solenoid valve 222 to act, so that the second pilot solenoid valve 222 is in the second position on the right side, and the control oil of the external control oil circuit enters the control cavity of the second hydraulic directional control valve 222 through the second pilot solenoid valve 222. The control oil pushes the spool of the second hydraulic directional control valve 221 to act against the elastic force of the second elastic buffer 72, thereby controlling the second hydraulic directional control valve 221 to be switched to the second working position on the right side.

[0054] As Figure 2 shown, the main directional control valve 21 and the high-low pressure switching valve 22 are of an integrated valve group 20 structure. The first pilot solenoid valve 212 and the second pilot solenoid valve 222 are both integrated on the valve body or the end cover. Among them, the valve body and the end cover can adopt a casting structure to reduce the pressure loss. Of course, the second pilot solenoid valve 222 can also be a two-position three-way solenoid valve, as long as it can achieve the above functions. It should be noted that the first pilot solenoid valve 212 and the second pilot solenoid valve 222 can both adopt cartridge solenoid valves, which are inserted into the valve body or the end cover. Other hydraulic components such as relief valves can also be inserted on the valve body. In addition, since the main directional control valve 21 and the high-low pressure switching valve 22 are both integrated in the same valve body, compared with the conventional plate valve group system, the system of the present application is simple, small in volume, light in weight, has a simple oil passage, and small pressure loss.

[0055] As Figure 2As shown in the figure, the fifth oil supply port A6 and the sixth oil supply port B6 of the first pilot solenoid valve 212 are respectively connected to the left and right control chambers of the first hydraulic directional control valve 211 through two first control oil channels 81; first elastic buffer members 71 are provided at both ends of the first hydraulic directional control valve 211, and the first elastic buffer members 71 are located in the end covers at both ends. When the first control oil channel 81 returns oil, the first elastic buffer members 71 drive the spool of the first hydraulic directional control valve 211 back to the middle position. The third oil supply port A4 of the second pilot solenoid valve 222 is connected to the control chamber on the right side of the second hydraulic directional control valve 221 through a second oil channel; the second elastic buffer member 72 is also located in the end cover of the second hydraulic directional control valve 221. When the second control oil channel 82 returns oil, the second elastic buffer member 72 drives the spool of the second hydraulic directional control valve 221 back to the first working position on the left side.

[0056] In the solution of the present application, there may be multiple main oil inlet ports P1 of the first hydraulic directional control valve 211, and the multiple main oil inlet ports P1 are connected through a first connecting oil channel 91. The number of main oil return ports T1 may be two, and the two main oil return ports T1 are connected through a second connecting oil channel 92.

[0057] In an embodiment of the present invention, a pressure control device 30 is further provided on the oil inlet path of the pumping hydraulic system. Among them, the pressure control device 30 may be a relief valve, and the relief valve is arranged on the oil inlet path where the main oil inlet port P1 is located to control the maximum working pressure of the system.

[0058] In an embodiment of the present invention, a concrete pumping machine is further proposed, including the pumping hydraulic system as above. This concrete pumping machine adopts all embodiments of the pumping hydraulic system as described above, so it has all the beneficial effects of the pumping hydraulic system, which will not be elaborated here one by one.

[0059] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0060] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or capable of communicating with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0062] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A pumping hydraulic system, comprising two pumping cylinders connected in series, characterized in that, The described pumping hydraulic system includes: A main oil pump (10) that pumps hydraulic oil to the pumping hydraulic system through a pumping oil circuit (L1); A main reversing valve (21) disposed on the pumping oil circuit (L1) and controlling the telescopic movements of the two pumping cylinders; and A high-low pressure switching valve (22), which is a two-position six-way electro-hydraulic reversing valve and is disposed on the oil supply circuit (L2) of the main reversing valve (21). The high-low pressure switching valve (22) and the main reversing valve (21) are an integrated valve group structure. The spool of the high-low pressure switching valve (22) can be switched between a first working position and a second working position, so that the hydraulic oil pumped by the main oil pump (10) enters the rod chamber or the non-rod chamber of one of the pumping cylinders through the high-low pressure switching valve (22); The main reversing valve (21) includes a first hydraulic reversing valve (211) and a first pilot solenoid valve (212) that controls the first hydraulic reversing valve (211) to switch between a first switching position and a second switching position. The first hydraulic reversing valve (211) also includes an intermediate cut-off position for unloading the system during commutation.

2. The pumping hydraulic system according to claim 1, characterized in that, The first hydraulic reversing valve (211) includes a main oil inlet (P1) and a main oil return port (T1) on one side, and a first oil supply port (A5) and a second oil supply port (B5) on the other side; In the first switching position, the first oil supply port (A5) is communicated with the main oil inlet (P1), and the second oil supply port (B5) is communicated with the main oil return port (T1); In the second switching position, the first oil supply port (A5) is communicated with the main oil return port (T1), and the second oil supply port (B5) is communicated with the main oil inlet (P1).

3. The pumping hydraulic system according to claim 2, characterized in that, The intermediate cut-off position is used to communicate the main oil inlet (P1) with the main oil return port (T1) and cut off both the first oil supply port (A5) and the second oil supply port (B5).

4. The pumping hydraulic system according to claim 2, characterized in that, The high-low pressure switching valve (22) is a two-position six-way electro-hydraulic reversing valve.

5. The pumping hydraulic system according to claim 4, characterized in that, The high-low pressure switching valve (22) includes a second hydraulic reversing valve (221). The first working oil port (A1) and the first second working oil port (B1) on the first side of the second hydraulic reversing valve (221) are respectively communicated with the rod chambers of the two pumping cylinders. The first third working oil port (A2) and the first fourth working oil port (B2) on the first side are respectively communicated with the non-rod chambers of the two pumping cylinders. The first working oil port (A3) and the first second working oil port (B3) on the second side of the second hydraulic reversing valve (221) are respectively communicated with the first oil supply port (A5) and the second oil supply port (B5) of the main reversing valve (21).

6. The pumping hydraulic system according to claim 5, characterized in that, The high-low pressure switching valve (22) also includes a second pilot solenoid valve (222) that controls the second hydraulic reversing valve (221) to switch between the first working position and the second working position, where: In the first working position, the third working oil port (A2) on the first side and the fourth working oil port (B2) on the first side are communicated, the first working oil port (A1) on the first side and the first working oil port (A3) on the second side are communicated, and the second working oil port (B1) on the first side and the second working oil port (B3) on the second side are communicated; In the second working position, the first working oil port (A1) on the first side and the second working oil port (B1) on the first side are communicated, the third working oil port (A2) on the first side and the first working oil port (A3) on the second side are communicated, and the fourth working oil port (B2) on the first side and the second working oil port (B3) on the second side are communicated.

7. The pumping hydraulic system according to claim 6, characterized in that, The second pilot solenoid valve (222) is a two-position four-way solenoid valve. The second pilot solenoid valve (222) includes an electromagnet for controlling the switching between the first position and the second position. The second pilot solenoid valve (222) includes a third oil supply port (A4), a fourth oil supply port (B4), a first oil inlet port (P2) and a first oil return port (T2). The third oil supply port (A4) is communicated with the cavity where the second working position of the second hydraulic directional control valve (221) is located; When in the first position, the second hydraulic directional control valve (221) unloads through the third oil supply port (A4); When in the second position, the hydraulic oil of the external control oil circuit enters the second hydraulic directional control valve (221) through the first oil inlet port (P2).

8. The pumping hydraulic system according to claim 6, characterized in that, The first pilot solenoid valve (212) and the second pilot solenoid valve (222) are both integrated on the valve body or the end cover.

9. The pumping hydraulic system according to any one of claims 1 to 8, characterized in that, A pressure control device (30) is further provided on the oil inlet path of the pumping hydraulic system.

10. A concrete pumping machine, characterized in that, It includes the pumping hydraulic system according to any one of claims 1 to 9.

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