Concrete pumping equipment and hydraulic system thereof

Abstract

The invention discloses concrete pumping equipment and a hydraulic system thereof, the hydraulic system of the concrete pumping equipment comprises a pumping oil cylinder group, a pressure switching valve group, a piston buffer hydraulic loop and a controller, the pumping oil cylinder group comprises a first oil cylinder and a second oil cylinder which are both three-cavity oil cylinders, and rod cavities of the first oil cylinder and the second oil cylinder form a communicating cavity; working oil ports on one side of the pressure switching valve group are respectively connected with rodless cavities and piston rod cavities of the first and second oil cylinders, and the other side of the pressure switching valve group is connected with first and second oil inlet and outlet paths; the piston buffer hydraulic loop is arranged between the first and second oil inlet and outlet paths and the communicating cavity; and the controller is used for controlling the piston buffering hydraulic loop to carry out hydraulic buffering on the telescopic limit stroke of the piston when the oil cylinder piston moves to a preset position adjacent to the end part of the oil cylinder. The controller is combined with the piston buffering hydraulic loop, connection and disconnection of the communication oil way between the communication cavity of the oil cylinder and the oil pump can be controlled in good time, and therefore the piston buffering problem of the three-cavity pumping oil cylinder is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of concrete pumping, and in particular, relates to a concrete pumping device and a hydraulic system thereof. Background Art

[0002] In construction, double-acting single-piston rod series oil cylinders are widely used. One cylinder extends forward and the other retracts, and the reciprocating cycle drives the concrete cylinder piston to suck or push materials to achieve concrete transportation. However, due to the large cylinder diameter and high speed of the pumping equipment, in order to reduce the impact force when the piston is in place, such as Figure 1 As shown, a pressure relief buffer device is generally used on the oil cylinder, that is, the U-shaped tube D shown in the figure. One rodless chamber and one rod chamber can be set respectively, which are called the rear U-shaped tube and the front U-shaped tube. One end of the rear U-shaped tube is always in communication with the rodless chamber, and the other end is set to communicate with the rod chamber when the piston retreats to the set position. One end of the front U-shaped tube is always in communication with the rod chamber, and the other end is set to communicate with the rodless chamber when the piston extends forward to the set position. In this way, when the piston moves to the set position, the rod chamber and the rodless chamber of the oil cylinder are connected through the U-shaped tube D, thereby reducing the hydraulic driving force of the oil cylinder piston and mitigating the impact force of the piston.

[0003] But in pumping equipment, in addition to double-acting cylinders, there is also a three-chamber cylinder, such as Figure 2 As shown. If a U-shaped tube is installed on a three-chamber oil cylinder, it will not play a buffering role. Figure 2 As shown, a three-chamber oil cylinder generally has chamber A and chamber B as oil inlet, which is equivalent to a cylinder with two rodless chambers; if the oil is inletted from chamber B, the pressure oil in chamber B cannot be relieved when the piston rod extends forward, and the U-shaped tube cannot play a buffering role. When the piston retreats, the pressure oil in chamber C is discharged to chamber A, but according to the buffering requirements, it should be discharged to chamber B, so it does not meet the requirements. In addition, opening an oil port on the pumping cylinder will cause abnormal wear of the piston when the piston passes through the hole, and the buffer time cannot be adjusted, which will affect the accuracy of the cylinder stroke. Summary of the invention

[0004] The purpose of the present application is to provide a concrete pumping device and a hydraulic system thereof, so as to effectively buffer the impact of the piston hitting the cylinder which may be caused by the piston's extreme stroke.

[0005] According to a first aspect of the present application, a concrete pumping equipment hydraulic system is provided.

[0006] The pumping cylinder group includes a first cylinder and a second cylinder, both of which are three-chamber cylinders, wherein the rod chamber of the first cylinder and the rod chamber of the second cylinder form a connecting chamber;

[0007] A pressure switching valve group, used for starting and stopping the pumping cylinder group and selecting the working chamber, wherein the working oil port on one side of the pressure switching valve group is respectively connected to the rodless chamber and the piston rod chamber of the first cylinder and the second cylinder, and the other side is connected to the first inlet and outlet oil circuit and the second inlet and outlet oil circuit;

[0008] A piston buffer hydraulic circuit is provided between the first inlet and outlet oil passage, the second inlet and outlet oil passage and the communicating chamber;

[0009] The controller is used to control the piston buffer hydraulic circuit to perform hydraulic buffering on the piston extension and contraction limit stroke when the cylinder piston moves to a preset cylinder end adjacent position.

[0010] In some embodiments, the controller is configured to:

[0011] Obtaining the travel direction and real-time position information of the oil cylinder piston;

[0012] Determine that the stroke direction is the piston extension direction and the real-time position information is reaching a preset cylinder front end adjacent position;

[0013] The piston buffer hydraulic circuit is controlled so that a relatively high-pressure oil circuit in the first inlet and outlet oil circuit and the second inlet and outlet oil circuit is communicated with the communication chamber.

[0014] In some embodiments, the controller is configured to:

[0015] Obtaining the travel direction and real-time position information of the oil cylinder piston;

[0016] Determining that the stroke direction is the piston recovery direction and the real-time position information is reaching a preset position adjacent to the rear end of the oil cylinder;

[0017] The piston buffer hydraulic circuit is controlled so that a relatively low-pressure oil passage in the first inlet and outlet oil passage and the second inlet and outlet oil passage is communicated with the communication chamber.

[0018] In some embodiments, the piston buffer hydraulic circuit comprises:

[0019] A first switching valve group includes a connecting cavity connecting oil port connected to the connecting cavity on one side and a first switching connecting oil port and a second switching connecting oil port connected to the first inlet and outlet oil passage on the other side, wherein the first switching valve group is used for switching the connecting cavity connecting oil port to the first switching connecting oil port, switching the connecting cavity connecting oil port to the second switching connecting oil port, or cutting off the connection between the connecting cavity connecting oil port and the first switching connecting oil port and the second switching connecting oil port;

[0020] A second switching valve group, comprising the communicating chamber connecting oil port connected to the communicating chamber on one side and a third switching connecting oil port and a fourth switching connecting oil port connected to the second inlet and outlet oil passage on the other side, the second switching valve group being used for switching the connecting oil port of the communicating chamber to the third switching connecting oil port, switching the connecting oil port of the communicating chamber to the fourth switching connecting oil port, or cutting off the connection between the connecting oil port of the communicating chamber and the third switching connecting oil port and the fourth switching connecting oil port;

[0021] Among them, the second switching connecting oil port is provided with a first one-way valve, which is used to allow hydraulic oil to flow from the first inlet and outlet oil circuit to the second switching connecting oil port and to cut off the reverse flow; the fourth switching connecting oil port is provided with a second one-way valve, which is used to allow hydraulic oil to flow from the second inlet and outlet oil circuit to the fourth switching connecting oil port and to cut off the reverse flow.

[0022] In some embodiments, the first switching connecting oil port is provided with a third one-way valve, and the third one-way valve is used to allow hydraulic oil to flow from the first switching connecting oil port to the first inlet and outlet oil circuit and to cut off the reverse flow; the third switching connecting oil port is provided with a fourth one-way valve, and the fourth one-way valve is used to allow hydraulic oil to flow from the third switching connecting oil port to the second inlet and outlet oil circuit and to cut off the reverse flow.

[0023] In some embodiments, the piston buffer hydraulic circuit comprises:

[0024] A multi-way reversing valve, comprising a connecting oil port and an oil return port both connected to the connecting oil port on one side, and a first connecting oil port connected to the first inlet and outlet oil path and a second connecting oil port connected to the second inlet and outlet oil path on the other side;

[0025] The communicating chamber connecting oil port is provided with an oil retaining one-way valve, and the oil retaining one-way valve is used to allow hydraulic oil to flow to the communicating chamber through the communicating chamber connecting oil port and to cut off the reverse flow.

[0026] In some embodiments, the oil return port is provided with an oil return one-way valve, and the oil return one-way valve is used to allow the hydraulic oil to flow from the communicating chamber to the oil return port and to cut off the reverse flow.

[0027] In some embodiments, the piston buffer hydraulic circuit comprises:

[0028] A reversing valve group, comprising a connecting oil port connected to the connecting oil port on one side and a first connecting oil port connected to the first inlet and outlet oil path and a second connecting oil port connected to the second inlet and outlet oil path on the other side;

[0029] a first oil cylinder connecting oil circuit, connecting the first oil cylinder and the first inlet and outlet oil circuit and provided with a first oil return check valve allowing hydraulic oil to flow from the first oil cylinder to the first inlet and outlet oil circuit;

[0030] a second oil cylinder connecting oil circuit, connecting the second oil cylinder and the second inlet and outlet oil circuit and provided with a second oil return check valve allowing hydraulic oil to flow from the second oil cylinder to the second inlet and outlet oil circuit;

[0031] The communicating cavity connecting oil port or the second connecting oil port is provided with an oil retaining one-way valve, and the oil retaining one-way valve is used to allow hydraulic oil to flow to the communicating cavity through the communicating cavity connecting oil port and to cut off the reverse flow.

[0032] In some embodiments, the first connecting oil port is also provided with an oil retaining one-way valve, and the oil retaining one-way valve is used to allow hydraulic oil to flow from the first inlet and outlet oil circuit to the first connecting oil port and to cut off the reverse flow.

[0033] In some embodiments, a first connection point of the first oil cylinder connecting oil circuit on the first oil cylinder and a second connection point of the second oil cylinder connecting oil circuit on the second oil cylinder respectively satisfy:

[0034] When the piston of the first oil cylinder retreats to a preset position adjacent to the rear end of the oil cylinder, the first connection point is communicated with the rod chamber of the first oil cylinder, and before the piston retreats to a preset position adjacent to the rear end of the oil cylinder, the first connection point is communicated with the rodless chamber of the first oil cylinder;

[0035] When the piston of the second cylinder retracts to a preset position adjacent to the rear end of the cylinder, the second connection point is connected to the rod chamber of the second cylinder, and before the piston retracts to a preset position adjacent to the rear end of the cylinder, the second connection point is connected to the rodless chamber of the second cylinder.

[0036] In some embodiments, the concrete pumping equipment hydraulic system includes:

[0037] A closed pump, wherein one end of the oil port of the closed pump is connected to the first inlet and outlet oil circuit, and the other end of the oil port is connected to the second inlet and outlet oil circuit.

[0038] In some embodiments, the concrete pumping equipment hydraulic system includes:

[0039] A reversing main valve, wherein one side of the reversing main valve is provided with an oil inlet and an oil return port, and two working oil ports on the other side are respectively connected to the first inlet and outlet oil circuit and the second inlet and outlet oil circuit;

[0040] An open pump pumps oil toward the oil inlet.

[0041] In some embodiments, the pressure switching valve group includes:

[0042] A first cartridge valve is arranged on the connecting oil path between the piston rod chamber of the first oil cylinder and the first inlet and outlet oil path;

[0043] A second cartridge valve is arranged on the connecting oil path between the piston rod chamber of the second oil cylinder and the second inlet and outlet oil path;

[0044] A third cartridge valve is arranged on the connecting oil path between the rodless chamber of the first oil cylinder and the first inlet and outlet oil path;

[0045] A fourth cartridge valve is provided on the connecting oil path between the rodless chamber of the second oil cylinder and the second inlet and outlet oil path;

[0046] A fifth cartridge valve is provided on the connecting oil path between the rodless chamber of the first oil cylinder and the rodless chamber of the second oil cylinder;

[0047] A sixth cartridge valve is provided on the connecting oil path between the piston rod chamber of the first oil cylinder and the piston rod chamber of the second oil cylinder;

[0048] Pilot valve group, used for pilot control of each cartridge valve.

[0049] In addition, the present application also provides a concrete pumping equipment, including the above-mentioned concrete pumping equipment hydraulic system.

[0050] In the concrete pumping equipment hydraulic system of the present application, by adding a piston buffer hydraulic circuit between the first and second inlet and outlet oil circuits and the connecting chamber, the controller combined with the piston buffer hydraulic circuit can timely control the opening and closing of the connecting oil circuit between the connecting chamber of the oil cylinder and the oil pump, so that the hydraulic pressure on both sides of the piston tends to balance, so as to solve the piston buffering problem of the three-chamber pumping cylinder. Compared with the buffering method of setting a U-shaped tube on the traditional oil cylinder, there is no need to control the opening and closing of the connecting oil circuit between the rodless chamber and the rod chamber of the oil cylinder, and there is no need to open a hole on the oil cylinder, and the piston will not cause abnormal wear of the seal due to the hole. Under certain working conditions, such as when the pumping speed is slow, the buffering can be stopped to improve the system efficiency and the accuracy of the stroke control. In addition, a fully electronically controlled buffering system can be used, and the buffering time can be determined according to the actual working conditions, which can better control the buffering effect and the stroke of the oil cylinder.

[0051] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0053] Figure 1 It is a structural schematic diagram of a double-acting single-piston-rod tandem oil cylinder provided with a U-shaped tube;

[0054] Figure 2 It is a schematic diagram of the structure of a three-chamber oil cylinder equipped with a U-shaped tube;

[0055] Figure 3 , Figure 4 All of them are hydraulic principle diagrams of the hydraulic system of the concrete pumping equipment according to the first embodiment of the present application, wherein Figure 4 The internal structure of the pressure switching valve group is shown;

[0056] Figure 5 A hydraulic principle diagram of a hydraulic system of a concrete pumping equipment according to a second embodiment of the present application;

[0057] Figure 6-1 to Figure 6-5 Pictured Figure 3 , Figure 4 Various variations of the switching valve group;

[0058] Figure 7 A hydraulic principle diagram of a hydraulic system of a concrete pumping equipment according to a third embodiment of the present application;

[0059] Figure 8 A hydraulic principle diagram of a hydraulic system of a concrete pumping equipment according to a fourth embodiment of the present application;

[0060] Fig. 9 A hydraulic principle diagram of a hydraulic system of a concrete pumping equipment according to a fifth embodiment of the present application;

[0061] Fig.10 A hydraulic principle diagram of a hydraulic system of a concrete pumping equipment according to a sixth embodiment of the present application; and

[0062] Fig.11 It is a hydraulic principle diagram of a hydraulic system of a concrete pumping equipment according to a seventh embodiment of the present application.

[0063] Description of Reference Numerals

[0064] 1 Closed pump 2 First oil cylinder

[0065] 3 Second oil cylinder 4 Pressure switching valve group

[0066] 5First switching valve group 6Second switching valve group

[0067] 7Third one-way valve 8First one-way valve

[0068] 9Fourth one-way valve 10 Second one-way valve

[0069] 11 Multi-way reversing valve 12 Oil retention check valve

[0070] 13 oil return check valve 14 reversing valve group

[0071] 15 First oil return check valve 16 Second oil return check valve

[0072] 17 Open pump 18 Reversing main valve

[0073] 41 first cartridge valve 42 second cartridge valve

[0074] 43 third cartridge valve 44 fourth cartridge valve

[0075] 45 fifth cartridge valve 46 sixth cartridge valve

[0076] 47 pilot valve group DU type pipe

[0077] L1 First inlet and outlet oil circuit L2 Second inlet and outlet oil circuit

[0078] A1 First switching connection port B1 Second switching connection port

[0079] A2 Third switch connection port B2 Fourth switch connection port

[0080] C1 First connection port C2 Second connection port

[0081] C Connecting cavity P Connecting cavity oil port

[0082] P1 Oil inlet T Oil return DETAILED DESCRIPTION

[0083] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0084] The concrete pumping equipment and the hydraulic system thereof according to the present application will be described below with reference to the accompanying drawings.

[0085] As mentioned above, in order to solve the problem of cylinder collision impact that may be caused by the piston limit stroke of the three-chamber oil cylinder, the present application discloses a hydraulic system for concrete pumping equipment. Figure 3 , Figure 4 As shown, in a specific embodiment, the hydraulic system of the concrete pumping equipment includes:

[0086] The pumping cylinder group includes a first cylinder 2 and a second cylinder 3, both of which are three-chamber cylinders, and the rod chamber of the first cylinder 2 and the rod chamber of the second cylinder 3 form a connecting chamber C;

[0087] The pressure switching valve group 4 is used to start and stop the pumping cylinder group and select the working chamber. The working oil port on one side of the pressure switching valve group 4 is respectively connected to the rodless chamber and the piston rod chamber of the first cylinder 2 and the second cylinder 3, and the other side is connected to the first inlet and outlet oil circuit L1 and the second inlet and outlet oil circuit L2;

[0088] A piston buffer hydraulic circuit is provided between the first inlet and outlet oil passage L1, the second inlet and outlet oil passage L2 and the communicating chamber C; and

[0089] The controller is used to control the piston buffer hydraulic circuit to hydraulically buffer the piston extension and contraction limit stroke when the cylinder piston moves to a preset cylinder end adjacent position.

[0090] It can be seen that the present application aims to add a piston buffer hydraulic circuit, combined with the timely control of the controller, so that once the cylinder piston moves to the position adjacent to the cylinder end, that is, close to or at the piston extension and retraction limit stroke, the added piston buffer hydraulic circuit can be used to make the oil chambers on both sides of the piston effectively connected (that is, the connecting chamber C is connected to the first inlet and outlet oil circuit L1 or the second inlet and outlet oil circuit L2), so that the hydraulic pressure difference on both sides tends to weaken, which can buffer the impact of piston displacement.

[0091] Based on the above design concepts, the controller can be configured as:

[0092] Obtain the travel direction and real-time position information of the cylinder piston;

[0093] Determine that the stroke direction is the piston extension direction and the real-time position information is reaching the preset cylinder front end adjacent position;

[0094] The piston buffer pressure circuit is controlled so that the relatively high pressure oil circuits in the first inlet and outlet oil circuit L1 and the second inlet and outlet oil circuit L2 are connected to the communication chamber C.

[0095] It is well known to those skilled in the art that a piston rod travel sensor or travel switch can be used to obtain the real-time position information of the oil cylinder piston in real time, and simply analyze the extension direction of the piston rod. Once the piston extension direction is determined and reaches the preset position adjacent to the front end of the oil cylinder, the piston buffer hydraulic circuit can be triggered to start, so that the relatively high-pressure oil circuit is connected to the connecting chamber C, thereby offsetting and slowing down the driving force of the high-pressure oil on the continued extension of the piston.

[0096] Similarly, the controller can also be configured as:

[0097] Obtain the travel direction and real-time position information of the cylinder piston;

[0098] Determine that the stroke direction is the piston recovery direction and the real-time position information is reaching the preset position adjacent to the rear end of the cylinder;

[0099] The piston buffer hydraulic circuit is controlled so that the relatively low-pressure oil paths in the first inlet and outlet oil path L1 and the second inlet and outlet oil path L2 are connected to the communication chamber C.

[0100] It can be seen that at the extreme retraction position of the piston, at least one action is performed: the connecting chamber C is connected to a relatively low-pressure oil circuit to reduce the driving force of the liquid pressure of the connecting chamber C on the retraction of the piston rod.

[0101] Of course, those skilled in the art can understand that the controller can also perform other actions, such as connecting the connecting chamber C with the relatively high-pressure oil circuit, slowing down the piston displacement speed, and then connecting the return oil, etc. Therefore, the controller is not limited to the above two basic control strategies, and can be specifically set according to the specific piston buffer hydraulic circuit and control process, including the switching control timing and triggering conditions of the hydraulic valve, etc., which are also described in the following implementation mode and will not be listed one by one, but they should all fall within the scope of protection of this application.

[0102] like Figures 3 to 5 As shown, a piston buffer hydraulic circuit of a specific embodiment may include:

[0103] The first switching valve group 5 includes a connecting cavity connecting oil port P connected to the connecting cavity C on one side and a first switching connecting oil port A1 and a second switching connecting oil port B1 connected to the first inlet and outlet oil path L1 on the other side. The first switching valve group 5 is used to switch the connection between the connecting cavity connecting oil port P and the first switching connecting oil port A1, switch the connection between the connecting cavity connecting oil port P and the second switching connecting oil port B1, or cut off the connection between the connecting cavity connecting oil port P and the first switching connecting oil port A1 and the second switching connecting oil port B1;

[0104] The second switching valve group 6 includes a connecting cavity connecting oil port P connected to the connecting cavity C on one side and a third switching connecting oil port A2 and a fourth switching connecting oil port B2 connected to the second inlet and outlet oil path L2 on the other side. The second switching valve group 6 is used to switch the connection between the connecting cavity connecting oil port P and the third switching connecting oil port A2, switch the connection between the connecting cavity connecting oil port P and the fourth switching connecting oil port B2, or cut off the connection between the connecting cavity connecting oil port P and the third switching connecting oil port A2 and the fourth switching connecting oil port B2;

[0105] Among them, the second switching connecting oil port B1 is provided with a first one-way valve 8, which is used to allow the hydraulic oil to flow from the first inlet and outlet oil circuit L1 to the second switching connecting oil port B1 and to cut off the reverse flow; the fourth switching connecting oil port B2 is provided with a second one-way valve 10, which is used to allow the hydraulic oil to flow from the second inlet and outlet oil circuit L2 to the fourth switching connecting oil port B2 and to cut off the reverse flow.

[0106] Among them, the connecting cavity connecting oil port P is connected to the connecting cavity of the pumping cylinder, and can also be connected to the rod cavities of the two cylinders respectively. The pressure switching valve group 4 has four connecting oil ports, two of which are respectively connected to the A cavity (i.e., rodless cavity) and B cavity (i.e., piston rod cavity) of the first cylinder 2, and the other two connecting oil ports are respectively connected to the A cavity and B cavity of the second cylinder 3. The pressure switching valve group 4 can connect the A and B oil ports of the closed pump 1 with the A and B cavities of the first cylinder 2 or the second cylinder 3 as needed, that is, the A oil port of the closed pump 1 can be connected to the A cavity or B cavity of the first cylinder 2, or to the A and B cavities at the same time, and the B oil port of the closed pump 1 can be connected to the A cavity or B cavity of the second cylinder 3, or to the A and B cavities at the same time.

[0107] The first switching valve group 5 can switch the connection direction between the P port and the A1 and B1 ports, and the second switching valve group 6 can switch the connection direction between the P port and the A2 and B2 ports. Electromagnetic drive is adopted to control the power gain and loss of the electromagnet to achieve different oil port connection states. Taking the first switching valve group 5 as an example, there are generally three states. State 1: The P port is connected to the A1 port, and the B1 port is disconnected; State 2: The P port is connected to the B1 port, and the A1 port is disconnected; State 3: The P port is not connected to either the A1 or B1 port.

[0108] It should be noted that the connection between the connecting chamber connecting oil port P and the connecting chamber C in the figure can use one pipeline or two pipelines, that is, the two switching valve groups can be connected to the connecting chamber C through pipelines respectively, or can be connected to the rod chambers of the two cylinders with two pipelines respectively, or can be connected to the rod chamber of one of the cylinders with one pipeline, all of which fall within the protection scope of the present application.

[0109] Among them, the pressure switching valve group 4 has various types. Figure 4 The figure shows a conventional pressure switching circuit using a two-way cartridge valve, which is composed of six cartridge valves and a pilot valve group 47. Specifically, the first cartridge valve 41 is arranged on the connecting oil circuit between the piston rod chamber of the first oil cylinder 2 and the first inlet and outlet oil circuit L1; the second cartridge valve 42 is arranged on the connecting oil circuit between the piston rod chamber of the second oil cylinder 3 and the second inlet and outlet oil circuit L2; the third cartridge valve 43 is arranged on the connecting oil circuit between the rodless chamber of the first oil cylinder 2 and the first inlet and outlet oil circuit L1; the fourth cartridge valve 44 is arranged on the connecting oil circuit between the rodless chamber of the second oil cylinder 3 and the second inlet and outlet oil circuit L2; the fifth cartridge valve 45 is arranged on the connecting oil circuit between the rodless chamber of the first oil cylinder 2 and the rodless chamber of the second oil cylinder 3; the sixth cartridge valve 46 is arranged on the connecting oil circuit between the piston rod chamber of the first oil cylinder 2 and the piston rod chamber of the second oil cylinder 3; the pilot valve group 47 is used to pilot control each cartridge valve, Figure 4The figure shows two electromagnetic reversing valves in the hydraulic pilot oil circuit, but it is obviously not limited to this. Through the control of the pilot valve group 47, the corresponding cartridge valve can be selected to open, so that the A chamber or B chamber of a certain oil cylinder is selected as the working chamber, and the pressure oil is introduced to drive the piston rod of the oil cylinder to extend and start pumping.

[0110] It should be noted that, when the piston rod of the pumping cylinder retracts, the pressure in its communication chamber is greater than the oil return port pressure of the closed pump 1. Therefore, in this case, Figure 5 As shown, only the first one-way valve 8 and the second one-way valve 10 need to be provided, but it is also possible to Figure 3 , Figure 4 As shown, a third one-way valve 7 and a fourth one-way valve 9 are added. That is, further, in Figure 3 , Figure 4 In the embodiment, the first switching connecting oil port A1 is also provided with a third one-way valve 7, which is used to allow the hydraulic oil to flow from the first switching connecting oil port A1 to the first inlet and outlet oil circuit L1 and to cut off the reverse flow; the third switching connecting oil port A2 may be provided with a fourth one-way valve 9, which is used to allow the hydraulic oil to flow from the third switching connecting oil port A2 to the second inlet and outlet oil circuit L2 and to cut off the reverse flow.

[0111] The first switching valve group 5 and the second switching valve group 6 can have various forms. Figure 6-1 As shown, two two-position two-way solenoid directional valves can be used. Figure 6-2 As shown, two two-position three-way solenoid valves can also be used. Figure 6-1 , the solenoid valve has an additional oil port that can be blocked or connected to the P port. Figure 6-3 As shown, a three-position four-way solenoid valve can also be used. In this case, there is an additional oil return port T, which can be connected back to the oil tank. It is particularly important to note that Figures 3 to 5 The combination of the first switching valve group 5 and the second switching valve group 6 can also be split to form another combination, such as Figure 6-4 , Figure 6-5 As shown, one switching valve group is responsible for switching between oil ports A1 and A2, and the other switching valve group is responsible for switching between oil ports B1 and B2. These variations are all conventional variations of valve bodies that can be thought of by those skilled in the art, and will not be given in detail here, but they should all fall within the scope of protection of this application.

[0112] by Figure 4 For example, when performing specific control, the system first detects the operating state and position state of the pumping cylinder; if the pumping cylinder is in the operating state, different specific control methods can be used according to the movement state and position state of the pumping cylinder:

[0113] Method 1: When the piston of the second oil cylinder 3 or the first oil cylinder 2 extends forward to the set position, the second switching valve group 6 / the first switching valve group 5 is activated by controlling the electromagnet, so that the P port is connected with the B2 port / the B1 port, and the P port is disconnected from the A2 port / the A1 port, and the hydraulic oil can flow from the B port / the A port of the closed pump 1 through the second check valve 10 / the first check valve 8, the second switching valve group 6 / the first switching valve group 5 to the connecting chamber C of the pumping oil cylinder. After the connecting chamber C is connected with the working chamber or the pressure oil port of the closed pump 1, it can resist the extension of the piston, slow down the extension speed of the piston, and avoid hitting the cylinder.

[0114] Furthermore, the first switching valve group 5 / the second switching valve group 6 can be controlled to operate, the P port is connected to the A1 port / the A2 port, and the P port is disconnected from the B1 port / the B2 port, and the hydraulic oil can flow from the connecting chamber C through the first switching valve group 5 / the second switching valve group 6, the third check valve 7 / the fourth check valve 9 to the A port / the B port of the closed pump 1. When the pumping cylinder is switched, the P port, the A2 port, the A1 port, the B2 port, and the B1 port of the second switching valve group 6 and the first switching valve group 5 are disconnected by controlling the electromagnet. Here, the first method is to use the extension of the pumping cylinder to the set position as the action signal of the switching valve group.

[0115] Method 2: When the first cylinder 2 / the second cylinder 3 retreats to the set position, the first switching valve group 5 / the second switching valve group 6 is actuated by controlling the electromagnet, the P port is connected to the A1 port / the A2 port, and the P port is disconnected from the B1 port / the B2 port, and the hydraulic oil can flow from the connecting chamber C through the first switching valve group 5 / the second switching valve group 6, the third check valve 7 / the fourth check valve 9 to the A port / the B port of the closed pump 1.

[0116] Furthermore, the second switching valve group 6 / first switching valve group 5 is actuated, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the second check valve 10 / first check valve 8, the second switching valve group 6 / first switching valve group 5 to the connecting chamber C of the pumping cylinder. After the pumping cylinder is switched, the P port, A2 port, A1 port, B2 port, and B1 port of the second switching valve group 6 and the first switching valve group 5 are disconnected by controlling the electromagnet. Here, the second method is to use the pumping cylinder retreating to the set position as the switching valve group action signal.

[0117] Mode 3: When the first oil cylinder 2 / the second oil cylinder 3 retreats to the set position, the first switching valve group 5 / the second switching valve group 6 is activated by controlling the electromagnet, the P port is connected with the A1 port / the A2 port, the B1 port / the B2 port is disconnected, and the hydraulic oil can flow from the communication chamber through the first switching valve group 5 / the second switching valve group 6, the third check valve 7 / the fourth check valve 9 to the A port / the B port of the closed pump 1. When the second oil cylinder 3 / the first oil cylinder 2 extends forward to the set position, the second switching valve group 6 / the first switching valve group 5 is activated, and the hydraulic oil can flow from the B port / the A port of the closed pump 1 through the second check valve 10 / the first check valve 8, the second switching valve group 6 / the first switching valve group 5 to the communication chamber C of the pumping oil cylinder. After the pumping oil cylinder is switched, the P port, the A2 port, the A1 port, the B2 port, and the B1 port of the second switching valve group 6 and the first switching valve group 5 are all disconnected by controlling the electromagnet. Here, in the third method, the pumping cylinder retreats to a set position as a switching valve group action signal, and the other pumping cylinder extends forward to a set position as another switching valve group action signal.

[0118] Mode 4: When the first oil cylinder 2 / second oil cylinder 3 retreats to the set position or the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position, the first switching valve group 5 / second switching valve group 6 is actuated, the P port is connected to the A1 port / A2 port, the P port is disconnected from the B1 port / B2 port, and the hydraulic oil can flow from the connecting chamber C through the first switching valve group 5 / second switching valve group 6, the third check valve 7 / fourth check valve 9 to the A port / B port of the closed pump 1. The second switching valve group 6 / first switching valve group 5 is actuated, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the second check valve 10 / first check valve 8, the second switching valve group 6 / first switching valve group 5 to the connecting chamber C of the pumping oil cylinder. Here, mode 3 is that as long as the pumping oil cylinder retreats to the set position or extends forward to the set position, it can be used as the switching valve group action signal.

[0119] Mode 5: When the first oil cylinder 2 / second oil cylinder 3 retreats to the set position and the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position, the first switching valve group 5 / second switching valve group 6 is activated, the P port is connected to the A1 port / A2 port, the P port is disconnected from the B1 port / B2 port, and the hydraulic oil can flow from the connecting chamber through the first switching valve group 5 / second switching valve group 6, the third check valve 7 / fourth check valve 9 to the A port / B port of the closed pump 1. The second switching valve group 6 / first switching valve group 5 is activated, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the second check valve 10 / first check valve 8, the second switching valve group 6 / first switching valve group 5 to the pumping cylinder connecting chamber. Here, mode 3 requires that the switching valve group is activated only when the piston of one pumping oil cylinder retreats to the set position and the piston of the other pumping oil cylinder extends forward to the set position.

[0120] It should be noted that in each of the above-mentioned specific control methods, the electromagnet may be controlled to act immediately when the set position is reached, or the electromagnet may be controlled to act after a delay of a period of time, and the delay time of each electromagnet may be different.

[0121] like Figure 8 As shown, in this embodiment, the piston buffer hydraulic circuit includes:

[0122] The multi-way reversing valve 11 includes a connecting cavity connecting oil port P and an oil return port T both connected to the connecting cavity C on one side, and a first connecting oil port C1 connected to the first inlet and outlet oil path L1 and a second connecting oil port C2 connected to the second inlet and outlet oil path L2 on the other side;

[0123] The communicating chamber connecting oil port P is provided with an oil retaining one-way valve 12, and the oil retaining one-way valve 12 is used to allow the hydraulic oil to flow to the communicating chamber C through the communicating chamber connecting oil port P and to cut off the reverse flow.

[0124] See also Figure 7 In another embodiment, the oil return port T is additionally provided with an oil return check valve 13, and the oil return check valve 13 is used to allow the hydraulic oil to flow from the connecting chamber C to the oil return port T and to cut off the reverse flow.

[0125] It can be seen that in Figure 7 , Figure 8 In the embodiment, a three-position four-way electromagnetic reversing valve (i.e., a multi-way reversing valve 11) can be used to replace Figures 3 to 5 The switching valve group shown in . Figure 7 The rest of the valve parts and Figures 3 to 5 The same as in the above, no longer repeat them one by one.

[0126] When performing specific control, the system first detects the operating status of the pumping cylinder and the position status of the pumping cylinder piston rod; if the pumping cylinder is in the operating state, it is controlled according to the movement direction and position of the pumping cylinder. Specifically, the following control methods can be used:

[0127] Method 1: When the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position, the multi-way reversing valve 11 is in the right position / left position by controlling the electromagnet, the P port of the multi-way reversing valve 11 is connected with the C2 port / C1 port, and the C1 port / C2 port is connected with the T port. The hydraulic oil can flow from the B port / A port of the closed pump 1, the multi-way reversing valve 11, and the oil-retaining check valve 12 and finally connect with the connecting chamber C of the pumping oil cylinder. The oil in the connecting chamber C can flow to the A port / B port of the closed pump 1 through the oil return check valve 13 and the multi-way reversing valve 11. After the pumping oil cylinder is reversed, the multi-way reversing valve 11 is returned to the middle position by controlling the electromagnet, and the P port, C2 port, C1 port, and T port are all disconnected. Here, method 1 uses the extension of the pumping oil cylinder to the set position as the action signal of the switching valve group.

[0128] Mode 2: When the first oil cylinder 2 / second oil cylinder 3 retreats to the set position, the multi-way reversing valve 11 is in the right position / left position by controlling the electromagnet, the P port of the multi-way reversing valve 11 is connected to the C2 port / C1 port, and the C1 port / C2 port is connected to the T port. The hydraulic oil can flow from the B port / A port of the closed pump 1, the multi-way reversing valve 11, and the oil-retaining check valve 12 and finally connect to the pumping cylinder connecting cavity. The oil in the connecting cavity can flow to the A port / B port of the closed pump 1 through the oil return check valve 13 and the multi-way reversing valve 11. After the pumping cylinder is reversed, the multi-way reversing valve 11 is returned to the middle position by controlling the electromagnet, and the P port, C2 port, C1 port, and T port are all disconnected. Here, mode 2 uses the retreat of the pumping cylinder to the set position as the action signal of the switching valve group.

[0129] Mode 3: When the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position or the first oil cylinder 2 / second oil cylinder 3 retreats to the set position, the multi-way reversing valve 11 is in the right position / left position by controlling the electromagnet, the P port of the multi-way reversing valve 11 is connected to the C2 port / C1 port, and the C1 port / C2 port is connected to the T port. The hydraulic oil can flow from the B port / A port of the closed pump 1, the multi-way reversing valve 11, and the oil-retaining check valve 12 and finally communicate with the connecting chamber C of the pumping oil cylinder. The oil in the connecting chamber C can flow to the A port / B port of the closed pump 1 through the oil return check valve 13 and the multi-way reversing valve 11. After the pumping oil cylinder is reversed, the multi-way reversing valve 11 is returned to the middle position by controlling the electromagnet, and the P port, C2 port, C1 port, and T port are all disconnected. Here, mode 3 is that as long as the pumping oil cylinder retreats to the set position or extends to the set position, it is used as the action signal of the switching valve group.

[0130] Mode 4: When the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position and the first oil cylinder 2 / second oil cylinder 3 retreats to the set position, the multi-way reversing valve 11 is in the right position / left position by controlling the electromagnet, the P port of the multi-way reversing valve 11 is connected to the C2 port / C1 port, and the C1 port / C2 port is connected to the T port. The hydraulic oil can flow from the B port / A port of the closed pump 1, the multi-way reversing valve 11, and the oil-retaining one-way valve 12 and finally communicate with the connecting chamber C of the pumping oil cylinder. The oil in the connecting chamber C can flow to the A port / B port of the closed pump 1 through the oil return one-way valve 13 and the multi-way reversing valve 11. After the pumping oil cylinder is reversed, the multi-way reversing valve 11 is returned to the middle position by controlling the electromagnet, and the P port, C2 port, C1 port, and T port are all disconnected. Here, mode 4 requires the pumping oil cylinder to retreat to the set position and extend to the set position before the switching valve group is activated.

[0131] It is particularly important to explain that in each of the above-mentioned specific control methods, the electromagnet may be controlled to act immediately when the set position is reached, or it may be controlled to act after a delay of a period of time, and the delay time of each electromagnet may be different.

[0132] If the pumping cylinder is in a stopped state, the control electromagnet returns the multi-way reversing valve 11 to the middle position, and P, C1, C2, and T are all in a disconnected state.

[0133] like Fig. 9 , Fig.10 As shown, in this embodiment, the piston buffer hydraulic circuit includes:

[0134] The reversing valve group 14 includes a connecting oil port P connected to the connecting oil port C on one side and a first connecting oil port C1 connected to the first inlet and outlet oil path L1 and a second connecting oil port C2 connected to the second inlet and outlet oil path L2 on the other side;

[0135] The first oil cylinder connecting oil circuit connects the first oil cylinder 2 and the first inlet and outlet oil circuit L1 and is provided with a first oil return check valve 15 that allows the hydraulic oil to flow from the first oil cylinder 2 to the first inlet and outlet oil circuit L1;

[0136] The second oil cylinder connecting oil circuit connects the second oil cylinder 3 and the second inlet and outlet oil circuit L2 and is provided with a second oil return check valve 16 that allows the hydraulic oil to flow from the second oil cylinder 3 to the second inlet and outlet oil circuit L2;

[0137] The connecting oil port P or the second connecting oil port C2 is provided with an oil retaining one-way valve 12, which is used to allow the hydraulic oil to flow to the connecting oil port P through the connecting oil port P to the connecting chamber C and to cut off the reverse flow.

[0138] It can be seen that in this embodiment, the oil circuit is connected through the reversing valve group 14 and the two oil cylinders, which can replace Figure 7 , Figure 8 The multi-way reversing valve 11 shown in FIG. 1 or alternatively Figures 3 to 5 The switching valve group shown in .

[0139] It should be noted that the first connection point of the first oil cylinder connecting oil circuit on the first oil cylinder 2 should meet the following requirements:

[0140] When the piston of the first cylinder 2 retreats to a preset position adjacent to the rear end of the cylinder, the first connection point is connected to the rod chamber of the first cylinder 2, and before the piston retreats to a preset position adjacent to the rear end of the cylinder, the first connection point is connected to the rodless chamber of the first cylinder 2.

[0141] Similarly, the second connection points of the second oil cylinder connecting oil circuit on the second oil cylinder 3 respectively meet the following conditions:

[0142] When the piston of the second cylinder 3 retreats to a preset position adjacent to the rear end of the cylinder, the second connection point is connected to the rod chamber of the second cylinder 3, and before the piston retreats to a preset position adjacent to the rear end of the cylinder, the second connection point is connected to the rodless chamber of the second cylinder 3.

[0143] It can be seen that the specific positions of the first connection point and the second connection point should be determined according to the stroke of the pumping cylinder.

[0144] In addition, Fig.10 In the illustrated embodiment, the first connecting oil port C1 is also provided with an oil retaining check valve 12, which is used to allow hydraulic oil to flow from the first inlet and outlet oil path L1 to the first connecting oil port C1 and to cut off the reverse flow.

[0145] In the reversing valve group 14, the connection direction between the P port and the C1 and C2 ports is electromagnetically driven, and different oil port connection states are achieved by controlling the gain and loss of electricity of the electromagnet. Generally, there are three states. State 1: The P port is connected to the C2 port, and the C1 port is disconnected; State 2: The P port is connected to the C1 port, and the C2 port is disconnected; State 3: The P port is not connected to either the C1 or C2 port.

[0146] As mentioned above, the first switching valve group 5 or the second switching valve group 6 can have a variety of valve structures, such as using two two-position two-way solenoid reversing valves, or two two-position three-way solenoid reversing valves, wherein the extra oil port of the solenoid valve can be blocked or connected to the P port. Alternatively, a three-position four-way solenoid valve, such as Figure 6-3 As shown, there is an additional oil return port T, and the oil return port T can be connected back to the oil tank. These should all fall within the protection scope of this application.

[0147] by Fig. 9 For example, when performing specific control, the system first detects the operating status of the pumping cylinder and the position status of the pumping cylinder piston rod; if the pumping cylinder is in the operating state, it is controlled according to the movement direction and position of the pumping cylinder. Specifically, the following control methods can be used:

[0148] Mode 1: When the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position, the reversing valve group 14 is activated by controlling the electromagnet, the P port is connected with the C2 port / C1 port, and the P port is disconnected from the C1 port / C2 port, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the reversing valve group 14 and the oil-retaining check valve 12 to the connecting chamber C of the pumping oil cylinder. At the same time, if the piston of the pumping oil cylinder retreats to the set position, the hydraulic oil in the rod chamber of the pumping oil cylinder can flow to the A port / B port of the closed pump 1 through the corresponding oil cylinder connecting oil path provided with the first oil return check valve 15 / second oil return check valve 16. After the pumping oil cylinder is reversed, the P port, C2 port, and C1 port of the reversing valve group 14 are all disconnected by controlling the electromagnet. In this mode, the extension of the pumping oil cylinder to the set position is used as the action signal of the switching valve group.

[0149] Mode 2: When the first oil cylinder 2 / second oil cylinder 3 retreats to the set position, the reversing valve group 14 is activated by controlling the electromagnet, the P port is connected with the C2 port / C1 port, and the P port is disconnected from the C1 port / C2 port, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the reversing valve group 14 and the oil-retaining check valve 12 to the pumping cylinder communication chamber. At the same time, if the piston of the pumping cylinder retreats to the set position, the hydraulic oil in the rod chamber of the pumping cylinder can flow to the A port / B port of the closed pump 1 through the corresponding oil cylinder connecting oil path provided with the first oil return check valve 15 / second oil return check valve 16. When the pumping cylinder is reversed, the P port, C2 port, and C1 port of the reversing valve group 14 are disconnected by controlling the electromagnet. In this mode, the retreat of the pumping cylinder to the set position is used as the action signal of the switching valve group.

[0150] Mode 3: When the first oil cylinder 2 / second oil cylinder 3 retreats to the set position or the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position, the reversing valve group 14 is activated by controlling the electromagnet, the P port is connected with the C2 port / C1 port, and the P port is disconnected from the C1 port / C2 port, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the reversing valve group 14 and the oil-retaining check valve 12 to the connecting chamber C of the pumping oil cylinder. At the same time, if the piston of the pumping oil cylinder retreats to the set position, the hydraulic oil in the rod chamber of the pumping oil cylinder can flow to the A port / B port of the closed pump 1 through the corresponding oil cylinder connecting oil path provided with the first oil return check valve 15 / second oil return check valve 16. After the pumping oil cylinder is reversed, the P port, C2 port, and C1 port of the reversing valve group 14 are all disconnected by controlling the electromagnet. In this mode, as long as the pumping oil cylinder retreats to the set position or extends forward to the set position, it can be used as the action signal of the switching valve group.

[0151] Mode 4: When the first oil cylinder 2 / second oil cylinder 3 retreats to the set position and the second oil cylinder 3 / first oil cylinder 2 extends forward to the set position, the reversing valve group 14 is activated by controlling the electromagnet, the P port is connected with the C2 port / C1 port, and the P port is disconnected from the C1 port / C2 port, and the hydraulic oil can flow from the B port / A port of the closed pump 1 through the reversing valve group 14 and the oil-retaining check valve 12 to the pumping cylinder communication chamber. At the same time, if the piston of the pumping cylinder retreats to the set position, the hydraulic oil in the rod chamber of the pumping cylinder can flow to the A port / B port of the closed pump 1 through the corresponding cylinder connecting oil path provided with the first oil return check valve 15 / second oil return check valve 16. After the pumping cylinder is reversed, the P port, C2 port, and C1 port of the reversing valve group 14 are all disconnected by controlling the electromagnet. This mode requires the pumping cylinder to retreat to the set position and extend forward to the set position before the switching valve group is activated.

[0152] In particular, in the above-mentioned methods, the electromagnet can be controlled to act when the set position is reached, or it can be controlled to act after a delay of a period of time after reaching the set position, and the delay time of each electromagnet can be different.

[0153] If the pumping cylinder is in a stopped state, the control electromagnet is in a power-off state, and the reversing valve groups 14P, A, and B are all in a disconnected state.

[0154] In the concrete pumping equipment hydraulic system of the aforementioned embodiment, a closed pump 1 is used. One end of the closed pump 1 is connected to the first inlet and outlet oil circuit L1, and the other end is connected to the second inlet and outlet oil circuit L2. When one of the A port and the B port at both ends of the closed pump 1 is the pumping oil port, the other is the return oil port. The closed pump 1 can rotate forward or reverse, so as to select the corresponding A port or B port as the pumping oil port.

[0155] It is important to note that, for example Fig.11 In the embodiment shown, the hydraulic system of the concrete pumping equipment may also use an open pump 17 . Unlike the closed pump 1 , the open pump 17 itself cannot be reversed, and therefore a reversing main valve 18 is required.

[0156] See also Fig.11 Specifically, one side of the reversing main valve 18 is provided with an oil inlet P1 and an oil return port T, and the two working oil ports on the other side are respectively connected to the first inlet and outlet oil circuit L1 and the second inlet and outlet oil circuit L2; the open pump 17 pumps oil toward the oil inlet P1. The reversing main valve 18 can change the connection direction between the P1 port and the T port and the oil circuit L1 and the oil circuit L2, for example, the P port can be connected to the oil circuit L1, and the oil circuit L2 is connected to the T port, or the P port can be connected to the oil circuit L2, and the oil circuit L1 is connected to the T port.

[0157] It can be seen that the comparison Fig.11 and Figure 4 , that is, the open pump 17 combined with the reversing main valve 18 can replace the closed pump 1. Those skilled in the art can understand that it is also possible to Figure 5 , Figures 7 to 10 The closed pump 1 is replaced by an open pump 17 combined with a reversing main valve 18, which will not be described in detail here.

[0158] In summary, the hydraulic system disclosed in the present application can effectively solve the piston buffering problem of the three-chamber pumping cylinder. Among them, a fully electronically controlled buffering system can be adopted, and the buffering time can be determined according to the actual working conditions (such as pumping speed, pumping pressure, stroke, etc.), which can better control the buffering effect and better control the cylinder stroke. Moreover, there is no need to drill holes in the cylinder, and the piston will not cause abnormal wear of the seal due to the through hole. Under certain working conditions, such as when the pumping speed is slow, the buffering can be stopped to improve the system efficiency and the accuracy of the stroke control.

[0159] Compared with the conventional buffering method, the important change in the oil circuit of the present application is that no U-shaped tube is set on the oil cylinder, and the switching valve group is used to control the opening and closing of the connecting oil circuit between the connecting chamber of the oil cylinder and the oil pump, rather than the opening and closing of the connecting oil circuit between the rodless chamber and the rod chamber of the oil cylinder, so it can adapt to three-chamber oil cylinders. Fig. 9 , Fig.10 In the implementation method, although a similar U-shaped tube is used to connect the oil circuit to control the buffer from the oil cylinder to the oil pump, it is different from the conventional U-shaped tube in that one oil port of the U-shaped tube is set on the oil cylinder, and the other oil port can be directly connected to the oil pump.

[0160] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0161] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0162] 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 conjunction with the embodiment or example are included in at least one embodiment or example of the present application. 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, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0163] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. Hydraulic system of concrete pumping equipment, It is characterized in that The concrete pumping equipment hydraulic system comprises: A pumping cylinder group comprises a first cylinder (2) and a second cylinder (3) both of which are three-chamber cylinders, wherein a rod chamber of the first cylinder (2) and a rod chamber of the second cylinder (3) form a connecting chamber (C); A pressure switching valve group (4) is used to start and stop the pumping oil cylinder group and select the working chamber, the working oil port on one side of the pressure switching valve group (4) is respectively connected to the rodless chamber and the piston rod chamber of the first oil cylinder (2) and the second oil cylinder (3), and the other side is connected to the first inlet and outlet oil circuit (L1) and the second inlet and outlet oil circuit (L2); A piston buffer hydraulic circuit is provided between the first inlet and outlet oil passage (L1), the second inlet and outlet oil passage (L2) and the communicating chamber (C); The controller is used to control the piston buffer hydraulic circuit to perform hydraulic buffering on the piston extension and contraction limit stroke when the cylinder piston moves to a preset cylinder end adjacent position.

2. The concrete pumping equipment hydraulic system according to claim 1, It is characterized in that The controller is configured to: Obtaining the travel direction and real-time position information of the oil cylinder piston; Determine that the stroke direction is the piston extension direction and the real-time position information is reaching a preset cylinder front end adjacent position; The piston buffer hydraulic circuit is controlled so that the relatively high-pressure oil circuits in the first inlet and outlet oil circuit (L1) and the second inlet and outlet oil circuit (L2) are connected to the communication chamber (C).

3. The concrete pumping equipment hydraulic system according to claim 1, It is characterized in that The controller is configured to: Obtaining the travel direction and real-time position information of the oil cylinder piston; Determining that the stroke direction is the piston recovery direction and the real-time position information is reaching a preset position adjacent to the rear end of the oil cylinder; The piston buffer hydraulic circuit is controlled so that the relatively low-pressure oil circuits in the first inlet and outlet oil circuit (L1) and the second inlet and outlet oil circuit (L2) are connected to the communication chamber (C).

4. The hydraulic system for concrete pumping equipment according to any one of claims 1 to 3, It is characterized in that The piston buffer hydraulic circuit comprises: a first switching valve group (5), comprising a connecting cavity connecting oil port (P) connected to the connecting cavity (C) on one side and a first switching connecting oil port (A1) and a second switching connecting oil port (B1) connected to the first inlet and outlet oil path (L1) on the other side, the first switching valve group (5) being used for switching the connection between the connecting cavity connecting oil port (P) and the first switching connecting oil port (A1), switching the connection between the connecting cavity connecting oil port (P) and the second switching connecting oil port (B1), or cutting off the connection between the connecting cavity connecting oil port (P) and the first switching connecting oil port (A1) and the second switching connecting oil port (B1); a second switching valve group (6), comprising the communicating chamber connecting oil port (P) connected to the communicating chamber (C) on one side and a third switching connecting oil port (A2) and a fourth switching connecting oil port (B2) connected to the second inlet / outlet oil path (L2) on the other side, the second switching valve group (6) being used for switching the connection between the communicating chamber connecting oil port (P) and the third switching connecting oil port (A2), switching the connection between the communicating chamber connecting oil port (P) and the fourth switching connecting oil port (B2), or cutting off the connection between the communicating chamber connecting oil port (P) and the third switching connecting oil port (A2) and the fourth switching connecting oil port (B2); The second switching connecting oil port (B1) is provided with a first one-way valve (8), and the first one-way valve (8) is used to allow hydraulic oil to flow from the first inlet and outlet oil circuit (L1) to the second switching connecting oil port (B1) and to cut off the reverse flow; the fourth switching connecting oil port (B2) is provided with a second one-way valve (10), and the second one-way valve (10) is used to allow hydraulic oil to flow from the second inlet and outlet oil circuit (L2) to the fourth switching connecting oil port (B2) and to cut off the reverse flow.

5. The concrete pumping equipment hydraulic system according to claim 4, It is characterized in that The first switching connecting oil port (A1) is provided with a third one-way valve (7), and the third one-way valve (7) is used to allow hydraulic oil to flow from the first switching connecting oil port (A1) to the first inlet and outlet oil circuit (L1) and to cut off the reverse flow; the third switching connecting oil port (A2) is provided with a fourth one-way valve (9), and the fourth one-way valve (9) is used to allow hydraulic oil to flow from the third switching connecting oil port (A2) to the second inlet and outlet oil circuit (L2) and to cut off the reverse flow.

6. The hydraulic system for concrete pumping equipment according to any one of claims 1 to 3, It is characterized in that The piston buffer hydraulic circuit comprises: A multi-way reversing valve (11), comprising a connecting chamber connecting oil port (P) and an oil return port (T) both connected to the connecting chamber (C) on one side, and a first connecting oil port (C1) connected to the first inlet and outlet oil path (L1) and a second connecting oil port (C2) connected to the second inlet and outlet oil path (L2) on the other side; The connecting chamber oil port (P) is provided with an oil-retaining one-way valve (12), and the oil-retaining one-way valve (12) is used to allow hydraulic oil to flow through the connecting chamber oil port (P) to the connecting chamber (C) and to cut off the reverse flow.

7. The concrete pumping equipment hydraulic system according to claim 6, It is characterized in that The oil return port (T) is provided with an oil return one-way valve (13), and the oil return one-way valve (13) is used to allow hydraulic oil to flow from the connecting chamber (C) to the oil return port (T) and to cut off the reverse flow.

8. The hydraulic system for concrete pumping equipment according to any one of claims 1 to 3, It is characterized in that The piston buffer hydraulic circuit comprises: A reversing valve group (14), comprising a connecting chamber connecting oil port (P) connected to the connecting chamber (C) on one side, and a first connecting oil port (C1) connected to the first inlet and outlet oil path (L1) and a second connecting oil port (C2) connected to the second inlet and outlet oil path (L2) on the other side; A first oil cylinder connecting oil circuit, connecting the first oil cylinder (2) and the first inlet and outlet oil circuit (L1) and provided with a first oil return check valve (15) allowing hydraulic oil to flow from the first oil cylinder (2) to the first inlet and outlet oil circuit (L1); A second oil cylinder connecting oil circuit, connecting the second oil cylinder (3) and the second inlet and outlet oil circuit (L2) and provided with a second oil return check valve (16) allowing hydraulic oil to flow from the second oil cylinder (3) to the second inlet and outlet oil circuit (L2); Wherein, the connecting chamber connecting oil port (P) or the second connecting oil port (C2) is provided with an oil retaining one-way valve (12), and the oil retaining one-way valve (12) is used to allow hydraulic oil to flow through the connecting chamber connecting oil port (P) to the connecting chamber (C) and to cut off the reverse flow.

9. The concrete pumping equipment hydraulic system according to claim 8, It is characterized in that The first connecting oil port (C1) is also provided with an oil-retaining one-way valve (12), and the oil-retaining one-way valve (12) is used to allow hydraulic oil to flow from the first inlet and outlet oil circuit (L1) to the first connecting oil port (C1) and to cut off the reverse flow.

10. The concrete pumping equipment hydraulic system according to claim 8, It is characterized in that The first connection point of the first oil cylinder connecting oil circuit on the first oil cylinder (2) and the second connection point of the second oil cylinder connecting oil circuit on the second oil cylinder (3) respectively meet the following conditions: When the piston of the first oil cylinder (2) retreats to a preset position adjacent to the rear end of the oil cylinder, the first connection point is communicated with the rod chamber of the first oil cylinder (2), and before the piston retreats to a preset position adjacent to the rear end of the oil cylinder, the first connection point is communicated with the rodless chamber of the first oil cylinder (2); When the piston of the second oil cylinder (3) retreats to a preset position adjacent to the rear end of the oil cylinder, the second connection point is connected to the rod chamber of the second oil cylinder (3), and before the piston retreats to a preset position adjacent to the rear end of the oil cylinder, the second connection point is connected to the rodless chamber of the second oil cylinder (3).

11. The concrete pumping equipment hydraulic system according to claim 1, It is characterized in that The concrete pumping equipment hydraulic system comprises: A closed pump (1), wherein one end oil port of the closed pump (1) is connected to the first inlet and outlet oil circuit (L1), and the other end oil port is connected to the second inlet and outlet oil circuit (L2).

12. The concrete pumping equipment hydraulic system according to claim 1, It is characterized in that The concrete pumping equipment hydraulic system comprises: A reversing main valve (18), wherein one side of the reversing main valve is provided with an oil inlet (P1) and an oil return port (T), and the other side has two working oil ports connected to the first inlet and outlet oil circuit (L1) and the second inlet and outlet oil circuit (L2) respectively; The open pump (17) pumps oil toward the oil inlet (P1).

13. The concrete pumping equipment hydraulic system according to claim 1, It is characterized in that The pressure switching valve group (4) comprises: A first cartridge valve (41) is arranged on the connecting oil path between the piston rod chamber of the first oil cylinder (2) and the first inlet and outlet oil path (L1); A second cartridge valve (42) is arranged on the connecting oil path between the piston rod chamber of the second oil cylinder (3) and the second inlet and outlet oil path (L2); A third cartridge valve (43) is arranged on the connecting oil path between the rodless chamber of the first oil cylinder (2) and the first inlet and outlet oil path (L1); A fourth cartridge valve (44) is arranged on the connecting oil path between the rodless chamber of the second oil cylinder (3) and the second inlet and outlet oil path (L2); A fifth cartridge valve (45) is arranged on the connecting oil path between the rodless chamber of the first oil cylinder (2) and the rodless chamber of the second oil cylinder (3); a sixth cartridge valve (46) arranged on the connecting oil path between the piston rod chamber of the first oil cylinder (2) and the piston rod chamber of the second oil cylinder (3); The pilot valve group (47) is used for pilot control of each cartridge valve.

14. Concrete pumping equipment, It is characterized in that The concrete pumping equipment comprises a concrete pumping equipment hydraulic system according to any one of claims 1 to 13.

Images