Backpressure device for adjusting return oil of heavy-load lifting platform high-flow hydraulic system

Abstract

The utility model relates to a backpressure device for adjusting return oil of a heavy-load lifting platform high-flow hydraulic system. The backpressure device comprises a control valve group and a low-pressure energy accumulator group which are arranged between an oil return opening of a main control valve of an executing mechanism and an oil tank, the control valve group comprises an oil inlet and an oil outlet; an oil return port, an oil inlet, an oil outlet and an oil tank of the executing mechanism main control valve are sequentially communicated through a pipe structure; the low-pressure energy accumulator set comprises a low-pressure energy accumulator set oil port and a low-pressure energy accumulator set oil return port, the low-pressure energy accumulator set oil port is communicated with a pipe structure between the main control valve oil return port and the control valve set through a pipe structure, and the low-pressure energy accumulator set oil return port is communicated with the oil tank through a pipe structure. According to the backpressure device, the oil return backpressure is adjusted through the control valve set and the low-pressure energy accumulator set, and the requirements of platform movement for stability and safety are met.

Description

Technical Field

[0001] This utility model belongs to the technical field of hydraulic systems, and in particular relates to a back pressure device for regulating return oil in a high-flow hydraulic system for heavy-duty lifting platforms. Background Technology

[0002] Currently, the hydraulic systems of large heavy-duty lifting platforms primarily rely on the pressure generated by their own weight to drive the back pressure device for oil return during platform descent. Under normal circumstances, to increase the smoothness of the platform's descent, a certain back pressure needs to be maintained on the load. Conventional hydraulic systems often employ check valves or relief valves for back pressure return, such as... Figure 1 As shown, the return oil back pressure generated by the hydraulic system is a fixed back pressure, which cannot be adjusted in real time. Furthermore, the required operating speed of the heavy-duty lifting platform varies depending on the load weight. During the platform's descent, the back pressure generated by the hydraulic system needs to gradually increase within an allowable range, which is insufficient to meet the platform's requirements for stability and safety. Therefore, a back pressure adjustment device for the high-flow hydraulic system of a heavy-duty lifting platform is needed, capable of real-time adaptive adjustment of the back pressure. Utility Model Content

[0003] This utility model provides a back pressure adjustment device for the high-flow hydraulic system of a heavy-duty lifting platform, which solves the problem that the fixed back pressure of the current one-way valve or relief valve structure is difficult to adjust and cannot meet the platform's requirements for stability and safety.

[0004] The purpose of this utility model and the technical problem it solves are achieved by the following technical solution.

[0005] This utility model provides a back pressure device for regulating the return oil of a high-flow hydraulic system for a heavy-duty lifting platform. The back pressure device includes: a control valve group and a low-pressure accumulator group located between the return oil port of the main control valve of the actuator and the oil tank; the control valve group includes an oil inlet and an oil outlet; the return oil port, oil inlet, oil outlet, and oil tank of the main control valve of the actuator are connected in sequence through a pipe structure; the low-pressure accumulator group includes a low-pressure accumulator group oil port and a low-pressure accumulator group return oil port, the low-pressure accumulator group oil port is connected to the pipe structure between the return oil port of the main control valve and the control valve group through a pipe structure, and the low-pressure accumulator group return oil port is connected to the oil tank through a pipe structure.

[0006] As an optional implementation, the control valve assembly further includes a valve block body, a flow control valve disposed on the valve block body, a pressure control valve disposed on the side of the valve block body, and a pressure sensor disposed on the top of the valve block body; the pressure sensor, the bottom valve port of the pressure control valve, the side valve port of the pressure control valve, the oil outlet, and the oil tank are connected by a pipe structure; the return oil port of the main control valve, the inlet oil port, the flow control valve, the pressure control valve, and the oil tank are connected in sequence by a pipe structure; wherein, the pressure sensor, the bottom valve port of the pressure control valve, the side valve port of the pressure control valve, the oil outlet, and the oil tank are connected in sequence by a pipe structure; the pressure sensor, the upper valve port of the pressure control valve, the drain port, and the oil tank are connected by a pipe structure.

[0007] As an optional implementation, the pressure control valve includes: a pressure control cone valve and a pressure control relief valve; the bottom valve ports of the flow control valve and the pressure control cone valve are connected, and an outlet ball valve is provided on the outlet port. A pipe structure between the outlet port and the outlet port at one end of the outlet ball valve is connected to a side valve port of the pressure control cone valve; a pipe structure between the outlet port at the other end of the outlet ball valve and the flow control valve is connected to the bottom valve port of the pressure control cone valve. Specifically, the inlet port of the pressure control relief valve and the upper valve port of the pressure control cone valve are connected via a pipe structure, which has a first connection interface; a second connection interface is provided on the pipe structure between the bottom valve port of the pressure control cone valve and the pressure sensor, and the second connection interface and the first connection interface are connected via a pipe structure; one end of the flow control valve is connected to the inlet port; the other end is connected to the pipe structure between the bottom valve port of the pressure control cone valve and the outlet ball valve.

[0008] As an alternative implementation, the flow control valve has multiple valves, which are configured as multiple parallel flow loops in the flow circuit.

[0009] As an optional implementation, a measuring point at the lower part of the pressure control cone valve is provided between the second connecting interface and the bottom valve port of the pressure control cone valve.

[0010] As an optional implementation, a control valve group pressure gauge is provided on the pipe structure between the lower measuring point of the pressure control cone valve and the flow control valve, and a control valve group pressure gauge switch is provided on the control valve group pressure gauge.

[0011] As an optional implementation, the low-pressure accumulator group also includes: a piston accumulator, a gas storage cylinder, a nitrogen charging valve group, and a safety valve group; the piston accumulator and the gas storage cylinder are located on the base of the low-pressure accumulator group and connected by a pipe structure, the nitrogen charging valve group is located on the pipe structure; and the safety valve group is located at the bottom of the piston accumulator.

[0012] As an optional implementation, the nitrogen charging valve assembly is equipped with a low-pressure accumulator pressure gauge.

[0013] As an optional implementation, the pipe structure between the low-pressure accumulator group pressure gauge and the nitrogen charging valve group is also provided with a low-pressure accumulator group pressure gauge line and a low-pressure accumulator group pressure gauge measuring point.

[0014] As an optional implementation, the safety valve group includes a first ball valve, a second ball valve, a relief valve, and a measuring point. The relief valve and the second ball valve are connected in parallel to the first and second connection interfaces of the safety valve group. The second connection interface is connected to the return oil port of the low-pressure accumulator group via a pipeline structure. The return oil port of the low-pressure accumulator group is connected to the oil tank via a pipeline structure. A measuring point is provided at one of the connection interfaces of the safety valve group. The first connection interface of the safety valve group is connected to the oil port of the low-pressure accumulator group and the piston accumulator via a pipeline structure.

[0015] Compared with the prior art, this utility model has obvious advantages and beneficial effects. Based on the above technical solution, this utility model has at least one of the following advantages and effects:

[0016] I. The present invention provides a back pressure device for regulating the return oil of a high-flow hydraulic system in a heavy-duty lifting platform. This back pressure device includes: a control valve assembly and a low-pressure accumulator assembly located between the return oil port of the main control valve of the actuator and the oil tank. The control valve assembly includes a valve block body, a flow control valve mounted on the valve block body, a pressure control valve located on the side of the valve block body, a pressure sensor located on the top of the valve block body, an oil inlet, and an oil outlet. The return oil port, oil inlet, oil outlet, and oil tank of the main control valve of the actuator are sequentially connected via a pipe structure. The low-pressure accumulator assembly includes a piston accumulator, a gas cylinder, a nitrogen charging valve assembly, a safety valve assembly, a low-pressure accumulator assembly pressure gauge connected to the nitrogen charging valve assembly, a low-pressure accumulator assembly oil port, and a low-pressure accumulator assembly return oil port. The piston accumulator and the gas cylinder are mounted on the base of the low-pressure accumulator assembly and connected via a pipe structure, and the nitrogen charging valve assembly is mounted on this pipe structure. The safety valve assembly is located at the bottom of the piston accumulator. The low-pressure accumulator group's oil port is connected to the main control valve's return oil port and the control valve assembly via a pipe structure. The low-pressure accumulator group's return oil port is also connected to the oil tank via a pipe structure. In this invention, during hydraulic system return oil operation, the flow control valve mounted on the valve block body regulates the system's return oil flow. This allows a portion of the oil to pass directly back to the oil tank through the flow control valve and then through the control valve assembly, while the remaining oil enters the low-pressure accumulator group and is stored there. This allows for real-time adjustment of the return oil back pressure via the flow control valve on the valve block body, enabling real-time adjustment of the back pressure value and / or adjustment of a fixed back pressure value. This improves the platform's stability and safety, meeting the platform's requirements for stability and safety.

[0017] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above-mentioned structure and other objects, features and advantages of this utility model more obvious and understandable, the following preferred embodiments are provided in conjunction with the accompanying drawings for detailed description. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the current overflow valve / check valve structure in a hydraulic system, showing the direction of oil flow.

[0019] Figure 2 This is a schematic diagram of the back pressure device in the hydraulic system, showing the flow direction of the oil.

[0020] Figure 3 This is a schematic diagram of the back pressure device in the hydraulic system in this embodiment.

[0021] Figure 4 This is a schematic diagram of the control valve assembly in this embodiment.

[0022] Figure 5 This is a top view of the low-voltage accumulator group in this embodiment.

[0023] Figure 6 This is a front view of the low-voltage energy storage unit in this embodiment.

[0024] Figure 7 This is a schematic diagram of the back pressure device in one embodiment of this invention.

[0025] Explanation of icon numbers:

[0026] 1: Back pressure device; 11: Control valve assembly

[0027] 112: Valve block body 113: Flow control valve

[0028] 11321: First flow control valve; 1132na: nth flow control valve

[0029] 1131a: Connects to interface one; 1151: Connects to interface two

[0030] 114: Pressure control valve 1141: Pressure control cone valve

[0031] 1142: Pressure-controlled relief valve; 1143: Lower measuring point of pressure-controlled cone valve

[0032] 115: Pressure sensor 116: Oil inlet

[0033] 117: Oil outlet 1171: Oil outlet ball valve

[0034] 118: Lifting point; 119: Oil drain port

[0035] 12: Low-voltage accumulator group

[0036] 120: Pressure gauge for control valve assembly; 1201: Pressure gauge switch for control valve assembly.

[0037] 121: Piston accumulator; 122: Gas storage cylinder

[0038] 123: Nitrogen charging valve assembly; 1231: First ball valve of nitrogen charging valve assembly.

[0039] 1232: Second ball valve of nitrogen charging valve assembly; 124: Safety valve assembly

[0040] 1241: First ball valve of the safety valve assembly; 1242: Second ball valve of the safety valve assembly.

[0041] 1243: Relief valve of safety valve assembly; 1244: Measuring point of safety valve assembly.

[0042] 1245: Safety valve assembly connection interface one 1246: Safety valve assembly connection interface two

[0043] 125: Pressure gauge for low-pressure accumulator group; 1251: Pressure gauge line for low-pressure accumulator group.

[0044] 1252: Pressure gauge measuring point of low-pressure accumulator group; 126: Oil port of low-pressure accumulator group.

[0045] 127: Low-pressure accumulator group return port 2: Main control valve return port

[0046] 3: Oil tank 31: Control valve group oil tank

[0047] 32: Low-pressure accumulator group oil tank Detailed Implementation

[0048] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended purpose of the invention, the following detailed description of the specific implementation methods, structures, features and effects of this utility model, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0049] This utility model provides a back pressure device for adjusting the return oil in a high-flow hydraulic system of a heavy-duty lifting platform, such as... Figure 2 and Figure 3As shown, a back pressure device 1 is provided between the main control valve return port 2 and the oil tank 3 of the actuator. This back pressure device 1 includes a control valve assembly 11 and a low-pressure accumulator assembly 12. The main control valve return port 2, the control valve assembly 11, and the oil tank 3 are sequentially connected by a pipe structure; the pipe structure between the main control valve return port 2 and the control valve assembly 11 and the oil tank 3 are connected by another pipe structure. The oil flow direction between the control valve assembly 11 and the low-pressure accumulator assembly 12 between the main control valve return port 2 and the oil tank 3 is as follows: Figure 2 As shown, the main control valve return port 2, control valve group 11, low-pressure accumulator group 12 and oil tank 3 of the actuator are all connected by a pipe structure.

[0050] In this utility model, such as Figure 4 As shown, the control valve assembly 11 includes a valve block body 112, a flow control valve 113, a pressure control valve 114, and a pressure sensor 115. An oil inlet 116 is located on the right side of the control valve assembly 11; an oil outlet 117, a lifting point 118, and a pressure sensor 115 are located at the top; the pressure control valve 114 is located on the left side; the flow control valve 113 and an oil drain port 119 are located on the side; and a control valve assembly pressure gauge 120 is located at the bottom. A lifting ring structure is provided at the lifting point 118 for lowering the control valve assembly 11.

[0051] In this utility model, such as Figure 5 and Figure 6 As shown, the low-pressure accumulator group 12 includes a piston accumulator 121, a gas cylinder 122, a nitrogen charging valve group 123, a safety valve group 124, a low-pressure accumulator group pressure gauge 125, a low-pressure accumulator group oil port 126, and a low-pressure accumulator group return oil port 127. Both the gas cylinder 122 and the piston accumulator 121 are mounted on the base of the low-pressure accumulator group 12. The gas cylinder 122 is connected to the piston accumulator 121 via a pipe structure circuit. The gas cylinder 122 and the piston accumulator 121 are connected via a pipe structure circuit. The nitrogen charging valve group 124 is located on the pipe structure circuit between the gas cylinder 122 and the piston accumulator 121. The safety valve group 124 is installed at the lower part of the piston accumulator 121.

[0052] In this utility model, such as Figure 7 As shown, the back pressure device 1 is connected to the oil return port of the main control valve through the control valve group 11 and the low-pressure accumulator group 12 respectively, and the oil tank 3 includes the control valve group oil tank 31 and the accumulator group oil tank 32.

[0053] In the control valve assembly 11 of this utility model, the flow control valve 113 includes multiple flow control valves, such as the first flow control valve 11321, ..., the nth flow control valve 1132na, where n is an integer greater than 1. The oil outlet 117 also includes an oil outlet ball valve 1171. The control valve assembly pressure gauge 120 also includes a control valve assembly pressure gauge switch 1201.

[0054] In the low-pressure accumulator group 12 of this utility model, the nitrogen charging valve group 123 further includes a first nitrogen charging ball valve 1231 and a second nitrogen charging ball valve 1232. The safety valve group 124 further includes a first safety valve 1241, a second safety valve 1242, a safety valve group overflow valve 1243, and a safety valve group measuring point 1244. The low-pressure accumulator group pressure gauge 125 further includes a low-pressure accumulator group pressure gauge line 1251 and a low-pressure accumulator group pressure gauge measuring point 1252.

[0055] Specifically, the back pressure device 1 includes a control valve assembly 11 and a low-pressure accumulator assembly 12 located between the return port 2 of the main control valve of the actuator and the oil tank 3. The control valve assembly 11 includes a valve block body 112, a flow control valve 113 located on the valve block body 112, a pressure control valve 114 located on the side of the valve block body 112, a pressure sensor 115 located on the top of the valve block body 112, an oil inlet 116, and an oil outlet 117. The pressure sensor 115, the bottom valve port of the pressure control valve 114, the side valve port of the pressure control valve 114, the oil outlet 117, and the oil tank 3 are connected by a pipe structure. The main control valve's return port 2, inlet port 116, flow control valve 113, pressure control valve 114, outlet port 117, and drain port 119 located beside the valve block body 112, along with the oil tank 3, are sequentially connected via a pipe structure. The pressure sensor 115, the bottom valve port of the pressure control valve 114, the side valve port of the pressure control valve 114, outlet port 117, and oil tank 3 are sequentially connected via a pipe structure. The pressure sensor 115, the upper valve port of the pressure control valve 114, drain port 119, and oil tank 3 are also connected via a pipe structure.

[0056] In this utility model, the pressure control valve 114 includes a pressure control cone valve 1141 and a pressure control relief valve 1142. The bottom valve ports of the flow control valve 113 and the pressure control cone valve 1141 are connected. An oil outlet ball valve 1171 is provided on the oil outlet 117. The pipe structure between the oil outlet port and the oil outlet 117 at one end of the oil outlet ball valve 1171 is connected to the side valve port of the pressure control cone valve 1141; the pipe structure between the oil outlet port and the flow control valve 113 at the other end of the oil outlet ball valve 1171 is connected to the bottom valve port of the pressure control cone valve 1141. The return port 2, inlet port 116, outlet port 117, and oil tank 3 of the actuator main control valve are connected in sequence through the pipe structure. Among them, the oil inlet port of the pressure control relief valve 1142 and the upper valve port of the pressure control cone valve 1141 are connected through the pipe structure, and the pipe structure is provided with a connection interface 1131a. A second connecting interface 1151 is provided on the pipe structure between the bottom valve port of the pressure control cone valve 1141 and the pressure sensor 115. The second connecting interface 1151 and the first connecting interface 1131a are connected by a pipe structure. A lower measuring point 1143 of the pressure control cone valve is provided between the second connecting interface 1151 and the bottom valve port of the pressure control cone valve 1141. One end of the flow control valve 113 is connected to the oil inlet 116; the other end is connected to the pipe structure between the bottom valve port of the pressure control cone valve 1141 and the oil outlet ball valve 1171. There are multiple flow control valves 113, and the multiple flow control valves 113 are set as multiple parallel flow circuits. A control valve group pressure gauge 120 is provided on the pipe structure between the lower measuring point 1143 of the pressure control cone valve and the flow control valve 113, and a control valve group pressure gauge switch 1201 is provided on the control valve group pressure gauge 120.

[0057] Furthermore, the low-pressure accumulator group 12 includes a piston accumulator 121, a gas storage cylinder 122, a nitrogen charging valve group 123, a safety valve group 124, a low-pressure accumulator group oil port 126 and a low-pressure accumulator group return oil port 127 connected to the safety valve group 124. The piston accumulator 121 and the gas storage cylinder 122 are mounted on the base of the low-pressure accumulator group 12 and connected by a pipe structure. The nitrogen charging valve group 123 is mounted on this pipe structure. The safety valve group 124 is located at the bottom of the piston accumulator 121. The safety valve group 124 includes a first ball valve 1241, a second ball valve 1242, an overflow valve 1243, and a measuring point 1244. The safety valve assembly overflow valve 1243 and the second ball valve 1242 are connected in parallel to the safety valve assembly connection interface one 1245 and the safety valve assembly connection interface two 1246. The safety valve assembly connection interface two 1246 is connected to the low-pressure accumulator group return port 127 on the low-pressure accumulator group 12 via a pipeline structure. The low-pressure accumulator group return port 127 is connected to the oil tank 3 via a pipeline structure. A safety valve assembly measuring point 1244 is provided at the safety valve assembly connection interface one 1245, and the safety valve assembly connection interface one 1245 is connected to the low-pressure accumulator group oil port 126 and the piston accumulator 121 via a pipeline structure. A low-pressure accumulator group pressure gauge 125 is provided on the nitrogen charging valve assembly 123. A low-pressure accumulator group pressure gauge line 1251 and a low-pressure accumulator group pressure gauge measuring point 1252 are also provided on the pipeline structure between the low-pressure accumulator group pressure gauge 125 and the nitrogen charging valve assembly 123. The low-pressure accumulator group oil port 126 is connected to the main control valve return port 2 and the control valve group 11 through a pipe structure, and the low-pressure accumulator group oil return port 127 is connected to the oil tank 3 through a pipe structure.

[0058] exist Figure 7 The ball valves (such as the first ball valve 1241, the second ball valve 1242, and the overflow valve 1243 of the safety valve group) connecting various pipe structures in the low-pressure accumulator group 12 are mainly used for the on / off control of the oil (gas) circuit. The pressure sensor 115 and the pressure gauge 125 of the low-pressure accumulator group in the control valve group 11 are used to collect and display the back pressure value during the platform descent process. The pressure control valve 114 of the control valve group 11 is used to set the minimum back pressure of the return oil and at the same time protect the piston accumulator 121 to extend the service life of the piston accumulator 121. After the heavy-duty lifting platform is lowered into place or during the interval of operation of the heavy-duty lifting platform, the oil filling the piston accumulator 121 is discharged back to the control valve group oil tank 31 through the flow control valve 113 and the pressure control valve 114.

[0059] The back pressure regulating device for oil return of this utility model has two functions: adjustable back pressure and fixed back pressure. Its main hydraulic process is as follows:

[0060] When the hydraulic system returns oil, the return oil flow rate is changed by adjusting the flow control valve 113 installed on the valve block body 112. This allows a portion of the oil to return directly to the oil tank 3 after passing through the flow control valve 113, while the remaining oil enters the low-pressure accumulator group 12 for storage. The low-pressure accumulator group is an important energy storage device in the hydraulic system. Based on Boyle's law for gases, it converts energy through gas compression. During use, a predetermined pressure of gas is first charged into the low-pressure accumulator group 12. When the hydraulic system pressure exceeds the internal pressure of the low-pressure accumulator group 12, oil is injected into the low-pressure accumulator group 12 to compress the gas, gradually reducing its volume. According to Boyle's law for gases, the gas pressure gradually increases throughout the operation. Since the gas pressure and oil pressure remain equal, the back pressure in the circuit gradually increases as the gas inside the low-pressure accumulator group 12 is compressed.

[0061] Specifically, the process of adjusting back pressure in this invention is as follows: Adjust the flow output of the flow control valve 113 to adjust the hydraulic system return flow to a preset flow range, making it lower than the maximum return flow of the hydraulic system. When the main control valve returns oil, a portion of the oil passes through the low-pressure control valve group 11 and returns directly to the low-pressure control valve group oil tank 31, while the other portion of the oil enters the piston accumulator 121 for storage. Due to the presence of the flow control valve 113, the back pressure of the oil passing through the low-pressure control valve group 11 and returning to the low-pressure control valve group oil tank 31 remains constant; while the volume of oil stored in the piston accumulator 121 continuously increases with the continuous return of oil from the hydraulic system, causing the gas volume in the piston accumulator 121 and the gas cylinder 122 to be continuously compressed, resulting in a corresponding increase in oil pressure. During the return process of the hydraulic system, the pressure at the main control valve return port 2 remains consistent with the oil pressure in the low-pressure accumulator group 12.

[0062] In this invention, the opening degree of the flow control valve 113 in the low-pressure control valve group 11 is adjusted to regulate the level of the return oil back pressure. When adjusting the back pressure in real time, if a back pressure range of 1MPa to 4MPa is required, the pressure control valve 114 can be set to the minimum pressure of 1MPa. In this case, as the platform descends, the pressure of the low-pressure accumulator group 12 gradually increases, reaching its maximum value of 4MPa when the platform reaches its final position. If a back pressure range of 2MPa to 5MPa is required, the pressure control valve 114 can be set to the minimum pressure of 2MPa. In this case, as the platform descends, the pressure of the low-pressure accumulator group 12 gradually increases, reaching its maximum value of 5MPa when the platform reaches its final position. Because the pressure of the low-pressure accumulator group 12 gradually increases during the platform's descent, the back pressure provided to the platform also gradually increases, thus offsetting more of the kinetic energy generated by the platform's movement. This completes the adjustment and setting of the fixed back pressure of the hydraulic system's return oil. The larger the opening of the flow control valve 113, the greater the return oil flow rate, resulting in a smaller volume of oil entering the piston accumulator 121 and a lower return oil back pressure. Conversely, the smaller the opening of the flow control valve 113, the smaller the return oil flow rate, resulting in a larger volume of oil entering the piston accumulator 121 and a higher return oil back pressure. Before the platform descends to the preset position, the oil level in the piston accumulator 121 reaches its maximum value, and the return oil back pressure reaches its highest back pressure value.

[0063] Specifically, the process of fixing the back pressure in this utility model is as follows:

[0064] In this invention, when a fixed back pressure is required for the hydraulic system's return oil, the first ball valve 1241 of the safety valve group at the oil inlet of the piston accumulator 121 can be closed, and all flow control valves 113 in the low-pressure control valve group 11 can be opened to their maximum, making them higher than the maximum flow rate of the hydraulic system's return oil. When the main control valve returns oil, all oil is directly returned to the low-pressure control valve group oil tank 31 through the low-pressure control valve group 11. At this time, a preset fixed back pressure can be set and adjusted within a certain back pressure range through the pressure control valve 114, thereby further improving the stability and safety requirements of the platform movement.

[0065] In this invention, adjusting the preset pressure value of the pressure control valve 114 can change the level of the return oil back pressure. That is, the smaller the preset pressure value of the pressure control valve 114, the lower the return oil back pressure; the larger the preset pressure value of the pressure control valve 114, the higher the return oil back pressure. The inlet of the control valve assembly 11 is connected to the outlet 2 of the main control valve of the actuator. The outlet 117 of the control valve assembly 11 is connected to the low-pressure control valve assembly oil tank 31 via a pipe structure. The drain port 119 of the control valve assembly 11 is connected to the low-pressure control valve assembly oil tank 31 via a pipe structure. The low-pressure accumulator assembly oil port 126 (e.g., the low-pressure accumulator assembly inlet / outlet) is connected to the outlet 2 of the main control valve of the actuator via a pipe structure. The safety valve assembly return port 127 of the low-pressure accumulator assembly 12 is connected to the low-pressure accumulator assembly oil tank 32 via a pipe structure.

[0066] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A back pressure device for regulating return oil in a high-flow hydraulic system of a heavy-duty lifting platform, characterized in that, The back pressure device (1) includes: a control valve group (11) and a low-pressure accumulator group (12) located between the main control valve return port (2) of the actuator and the oil tank (3); The control valve assembly (11) includes an oil inlet (116) and an oil outlet (117); The main control valve of the actuator has its return port (2), inlet port (116), outlet port (117), and oil tank (3) connected in sequence through a pipe structure; The low-pressure accumulator group (12) includes a low-pressure accumulator group oil port (126) and a low-pressure accumulator group return oil port (127). The low-pressure accumulator group oil port (126) is connected to the main control valve return oil port (2) and the control valve group (11) through a pipe structure. The low-pressure accumulator group return oil port (127) is connected to the oil tank (3) through a pipe structure.

2. The back pressure device according to claim 1, characterized in that, The control valve assembly (11) also includes a valve block body (112), a flow control valve (113) disposed on the valve block body (112), a pressure control valve (114) disposed on the side of the valve block body (112), and a pressure sensor (115) disposed on the top of the valve block body (112); The main control valve return port (2), the oil inlet (116), the flow control valve (113), the pressure control valve (114), and the oil tank (3) are connected in sequence through a pipe structure; Among them, the pressure sensor (115), the bottom valve port of the pressure control valve (114), the side valve port of the pressure control valve (114), the oil outlet (117) and the oil tank (3) are connected in sequence through a pipe structure; The pressure sensor (115), the upper valve port of the pressure control valve (114), the drain port (119), and the oil tank (3) are connected by a pipe structure.

3. The back pressure device according to claim 2, characterized in that, The pressure control valve (114) includes: a pressure control cone valve (1141) and a pressure control relief valve (1142); The bottom valve ports of the flow control valve (113) and the pressure control cone valve (1141) are connected. An oil outlet ball valve (1171) is provided on the oil outlet (117). The pipe structure between the oil outlet (117) and the oil outlet (117) at one end of the oil outlet ball valve (1171) is connected to the side valve port of the pressure control cone valve (1141). The pipe structure between the oil outlet (1171) at the other end of the oil outlet ball valve (1171) and the flow control valve (113) is connected to the bottom valve port of the pressure control cone valve (1141). Among them, the oil inlet of the pressure control relief valve (1142) and the upper valve port of the pressure control cone valve (1141) are connected by a pipe structure, and the pipe structure is provided with a connection interface (1131a). The pressure control cone valve (1141) has a second connecting interface (1151) on the pipe structure between the bottom valve port and the pressure sensor (115), and the second connecting interface (1151) and the first connecting interface (1131a) are connected by the pipe structure. One end of the flow control valve (113) is connected to the oil inlet (116); the other end is connected to the pipe structure between the bottom valve port of the pressure control cone valve (1141) and the oil outlet ball valve (1171).

4. The back pressure device according to claim 2, characterized in that, The flow control valve (113) has multiple valves, and the multiple flow control valves (113) are configured as multiple flow loops connected in parallel on the flow loop.

5. The back pressure device according to claim 4, characterized in that, A measuring point (1143) at the bottom of the pressure control cone valve is provided between the connecting interface 2 (1151) and the bottom valve port of the pressure control cone valve (1141).

6. The back pressure device according to claim 5, characterized in that, A control valve group pressure gauge (120) is provided on the pipe structure between the lower measuring point (1143) of the pressure control cone valve and the flow control valve (113), and a control valve group pressure gauge switch (1201) is provided on the control valve group pressure gauge (120).

7. The back pressure device according to claim 1, characterized in that, The low-voltage accumulator group (12) also includes: Piston accumulator (121), gas storage cylinder (122), nitrogen filling valve assembly (123), safety valve assembly (124); Piston accumulator (121) and gas cylinder (122) are located on the base of low-pressure accumulator group (12) and connected by a pipe structure. Nitrogen filling valve group (123) is located on the pipe structure. The safety valve assembly (124) is located at the bottom of the piston accumulator (121).

8. The back pressure device according to claim 7, characterized in that, The nitrogen charging valve assembly (123) is equipped with a low-pressure accumulator assembly pressure gauge (125).

9. The back pressure device according to claim 8, characterized in that, The pipe structure between the low-pressure accumulator group pressure gauge (125) and the nitrogen charging valve group (123) is also equipped with a low-pressure accumulator group pressure gauge line (1251) and a low-pressure accumulator group pressure gauge measuring point (1252).

10. The back pressure device according to claim 7, characterized in that, The safety valve assembly (124) includes a first ball valve (1241), a second ball valve (1242), a relief valve (1243), and a measuring point (1244). The safety valve group overflow valve (1243) and the safety valve group second ball valve (1242) are connected in parallel to the safety valve group connection interface one (1245) and the safety valve group connection interface two (1246). The safety valve group connection interface two (1246) is connected to the low-pressure accumulator group return oil port (127) provided on the low-pressure accumulator group (12) through a pipeline structure. The low-pressure accumulator group return oil port (127) is connected to the oil tank (3) through a pipeline structure. A safety valve assembly measuring point (1244) is provided at the first (1245) connection interface of the safety valve assembly; Furthermore, the safety valve assembly connection interface 1 (1245) is connected to the low-pressure accumulator assembly oil port (126) and the piston accumulator (121) through a pipe structure.

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