Outrigger hydraulic system and engineering machine

Abstract

A support leg hydraulic system comprises a control valve group, a horizontal oil cylinder, a vertical oil cylinder and a safety valve, the control valve group has an oil inlet P, an oil return port T, a first oil port A1, a second oil port B1 and a third oil port A2; the oil inlet P is communicated to a main oil path, and the oil return port T is communicated to an oil return path; the first oil port A1 is communicated to a rod cavity of the horizontal oil cylinder, the second oil port B1 is communicated to a non-rod cavity of the horizontal oil cylinder, the third oil port A2 is communicated to a non-rod cavity of the vertical oil cylinder through a first oil path, and a fourth oil port B2 is communicated to a rod cavity of the vertical oil cylinder through a second oil path. The bidirectional hydraulic lock comprises a first hydraulic control check valve and a second hydraulic control check valve, the first hydraulic control check valve is arranged on the first oil path, the second hydraulic control check valve is arranged on the second oil path, and an oil inlet of the safety valve is communicated to an oil path between the second hydraulic control check valve and the rod cavity of the vertical oil cylinder. The support leg hydraulic system can improve the safety performance of the whole machine. The application also relates to an engineering machine with the support leg hydraulic system.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, and in particular to a hydraulic system for outriggers and engineering machinery having the hydraulic system for outriggers. Background Technology

[0002] With the advancement of national production and construction, construction machinery, especially large-scale construction machinery, plays an increasingly important role in people's production and daily life. The safety performance of large-scale construction machinery has always been one of the most important indicators for evaluating it, and the outrigger system, which plays a crucial role in the stability of construction machinery, is particularly important in terms of safety performance. The main function of outriggers is to provide a stable and flat support surface, enabling the outriggers of construction machinery to firmly support the entire machine on various complex terrains and ground surfaces. For example, on unstable ground such as soft soil, mud, and sand, outriggers can effectively distribute the pressure on the ground, preventing the machinery from sinking or tilting; on hard ground such as concrete and stone slabs, outriggers can provide sufficient friction to prevent the machinery from sliding or moving during operation. In addition to its basic support function, outriggers also improve construction safety, reduce vehicle damage, and lower maintenance costs.

[0003] Outriggers can be broadly classified into three categories: fixed outriggers, deployable outriggers, and hydraulic outriggers. Hydraulic outriggers use the liquid pressure of hydraulic oil to adjust the height and stabilize mechanical equipment, making the equipment more stable and precise in different construction situations. Therefore, they are widely used in various engineering machinery.

[0004] Currently, the hydraulic systems for outriggers in construction machinery on the market use high-pressure cylinders as actuators. High-pressure cylinders have advantages such as reliable performance and high energy transfer density. Outrigger systems generally include four outriggers: left front, right front, left and right, and right rear. Each outrigger in the hydraulic system is equipped with a horizontal cylinder and a vertical cylinder. The horizontal cylinder extends and retracts the outrigger. After the outrigger is extended, the vertical cylinder supports the construction machinery off the ground for lifting. Because the vertical cylinder must bear the weight of the construction machinery itself and the load during lifting, it is highly susceptible to "cylinder expansion" failure under special working conditions. This means that the rod chamber of the vertical cylinder may deform or leak due to excessive pressure. Simultaneously, the pressure of the hydraulic oil in the pipelines connected to the rodless and rod chambers of the vertical cylinder also increases accordingly, potentially causing other components in the hydraulic circuit to malfunction or be damaged. Similarly, this failure can also occur in the horizontal cylinder, posing a safety hazard to the outrigger hydraulic system. Summary of the Invention

[0005] In view of this, the present invention provides a hydraulic system for outriggers and engineering machinery having the hydraulic system for outriggers, which can greatly ensure the safety and reliability of the hydraulic system for outriggers, thereby improving the overall safety performance of the machine.

[0006] The outrigger hydraulic system provided in this embodiment of the invention includes a control valve assembly, a horizontal cylinder, a vertical cylinder, a safety valve, and a two-way hydraulic lock. The control valve assembly has an inlet port P, a return port T, a first port A1, a second port B1, and a third port A2. The inlet port P is connected to the main oil circuit, and the return port T is connected to the return oil circuit. The first port A1 is connected to the rod chamber of the horizontal cylinder, the second port B1 is connected to the rodless chamber of the horizontal cylinder, the third port A2 is connected to the rodless chamber of the vertical cylinder through the first oil circuit, and the fourth port B2 is connected to the rod chamber of the vertical cylinder through the second oil circuit. The two-way hydraulic lock includes a first hydraulically controlled check valve and a second hydraulically controlled check valve. The first hydraulically controlled check valve is disposed on the first oil circuit, and the second hydraulically controlled check valve is disposed on the second oil circuit. The inlet port of the safety valve is connected to the oil circuit between the second hydraulically controlled check valve and the rod chamber of the vertical cylinder, and the outlet port of the safety valve is connected to the return oil circuit.

[0007] Furthermore, the safety valve is a pressure relief valve.

[0008] Furthermore, it also includes a first pressure sensor and a second pressure sensor. The first pressure sensor is used to monitor the hydraulic oil pressure in the rod chamber of the vertical cylinder, and the second pressure sensor is used to monitor the hydraulic oil pressure in the rodless chamber of the vertical cylinder. The outrigger hydraulic system stops working when the hydraulic oil pressure in the rod chamber of the vertical cylinder exceeds a first set value and / or the hydraulic oil pressure in the rodless chamber of the vertical cylinder exceeds a second set value.

[0009] Furthermore, both the first setting value and the second setting value are less than the setting value of the safety valve.

[0010] Furthermore, it also includes a third pressure sensor and a fourth pressure sensor. The third pressure sensor is used to monitor the hydraulic oil pressure in the rod chamber of the horizontal cylinder, and the fourth pressure sensor is used to monitor the hydraulic oil pressure in the rodless chamber of the horizontal cylinder. The outrigger hydraulic system stops working when the hydraulic oil pressure in the rod chamber of the horizontal cylinder exceeds a third set value and / or the hydraulic oil pressure in the rodless chamber of the horizontal cylinder exceeds a fourth set value.

[0011] Furthermore, it also includes a PLC controller, wherein the first pressure sensor, the second pressure sensor, the third pressure sensor, and the fourth pressure sensor are all connected to the PLC controller. The PLC controller is used to receive the hydraulic oil pressure signals monitored by the first pressure sensor, the second pressure sensor, the third pressure sensor, and the fourth pressure sensor, and to control whether the outrigger hydraulic system stops working based on the received hydraulic oil pressure signals.

[0012] Furthermore, the control valve assembly includes a first control valve and a second control valve. The first oil port A1 and the second oil port B1 of the control valve assembly are the two working oil ports of the first control valve, and the third oil port A2 and the fourth oil port B2 of the control valve assembly are the two working oil ports of the second control valve. The oil inlet P of the control valve assembly is connected to the oil inlet of the first control valve and the oil inlet of the second control valve, respectively, and the oil return port T of the control valve assembly is connected to the oil return port of the first control valve and the oil return port of the second control valve, respectively.

[0013] Furthermore, the first control valve has a first operating state and a second operating state. When the first control valve is in the first operating state, the oil inlet P is connected to the second oil port B1, and the first oil port A1 is connected to the oil return port T. When the first control valve is in the second operating state, the oil inlet P is connected to the first oil port A1, and the second oil port B1 is connected to the oil return port T. The second control valve also has a first operating state and a second operating state. When the second control valve is in the first operating state, the oil inlet P is connected to the fourth oil port B2, and the third oil port A2 is connected to the oil return port T. When the second control valve is in the second operating state, the oil inlet P is connected to the third oil port A2, and the fourth oil port B2 is connected to the oil return port T.

[0014] Furthermore, the outrigger hydraulic system also includes a first quick connector and a second quick connector. The first quick connector is located on the oil line from the oil inlet P of the control valve assembly to the main oil line, and the second quick connector is located on the oil line from the oil return port T of the control valve assembly to the return oil line.

[0015] The present invention also provides an engineering machine, including the above-described outrigger hydraulic system.

[0016] In summary, the outrigger hydraulic system of the present invention includes a control valve assembly, a horizontal cylinder, a vertical cylinder, a safety valve, and a bidirectional hydraulic lock. The control valve assembly has an inlet port P, a return port T, a first port A1, a second port B1, and a third port A2. The inlet port P is connected to the main oil circuit, and the return port T is connected to the return oil circuit. The first port A1 is connected to the rod chamber of the horizontal cylinder, the second port B1 is connected to the rodless chamber of the horizontal cylinder, the third port A2 is connected to the rodless chamber of the vertical cylinder via the first oil circuit, and the fourth port B2 is connected to the rod chamber of the vertical cylinder via the second oil circuit. The bidirectional hydraulic lock includes a first hydraulically controlled check valve and a second hydraulically controlled check valve. The first hydraulically controlled check valve is disposed on the first oil circuit, and the second hydraulically controlled check valve is disposed on the second oil circuit. The inlet port of the safety valve is connected to the oil circuit between the second hydraulically controlled check valve and the rod chamber of the vertical cylinder, and the outlet port of the safety valve is connected to the return oil circuit. By installing a safety valve on the oil line connecting to the rod chamber of the vertical cylinder, and integrating the safety valve on one side of the two-way hydraulic lock and close to the rod chamber end of the vertical cylinder, the safety valve releases pressure when the pressure of the hydraulic oil in the rod chamber of the vertical cylinder exceeds the set value of the safety valve. This effectively avoids faults such as "cylinder expansion" and "internal leakage" caused by the formation of a booster cylinder effect in the vertical cylinder, thereby greatly improving the overall safety performance of the machine.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the outrigger hydraulic system according to a preferred embodiment of the present invention.

[0019] Figure 2 yes Figure 1 The outrigger hydraulic system shown is configured to control the outrigger pressure signal when a blockage occurs. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention in order to achieve the intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0021] Figure 1 This is a schematic diagram of the outrigger hydraulic system according to a preferred embodiment of the present invention. Please refer to it. Figure 1The outrigger hydraulic system of the present invention includes a control valve assembly 20, a horizontal cylinder 30, a vertical cylinder 40, and a safety valve 50. The control valve assembly 20 has an inlet port P, a return port T, a first port A1, a second port B1, and a third port A2. The inlet port P is connected to the main oil circuit, and the return port T is connected to the return oil circuit. The first port A1 is connected to the rod chamber of the horizontal cylinder 30, the second port B1 is connected to the rodless chamber of the horizontal cylinder 30, the third port A2 is connected to the rodless chamber of the vertical cylinder 40 via a first oil circuit 101, and the fourth port B2 is connected to the rod chamber of the vertical cylinder 40 via a second oil circuit 102. The bidirectional hydraulic lock 60 includes a first hydraulically controlled check valve 61 and a second hydraulically controlled check valve 62. The first hydraulically controlled check valve 61 is disposed on the first oil circuit 101, and the second hydraulically controlled check valve 62 is disposed on the second oil circuit 102. The inlet of the safety valve 50 is connected to the oil circuit between the second hydraulically controlled check valve 62 and the rod chamber of the vertical cylinder 40, and the outlet of the safety valve 50 is connected to the return oil circuit or back to the oil tank. Preferably, the safety valve 50 is a pressure relief valve.

[0022] The main oil circuit provides hydraulic oil to the outrigger hydraulic system to control the operation of various components in the outrigger hydraulic system, including the oil tank and main pump. The return oil circuit is used to return the hydraulic oil to the oil tank for reuse. When the outrigger hydraulic system becomes blocked, preventing the outrigger hydraulic system from returning oil, high pressure will be formed in the rod chamber of the vertical cylinder 40. This invention solves this problem by installing a safety valve 50 on the oil circuit connected to the rod chamber of the vertical cylinder 40. The safety valve 50 is integrated into one side of the two-way hydraulic lock 60 and close to the rod chamber end of the vertical cylinder 40. When the pressure of the hydraulic oil in the rod chamber of the vertical cylinder 40 exceeds the set value of the safety valve 50 (i.e., the maximum pressure value that the safety valve can withstand), the safety valve 50 releases pressure, effectively avoiding malfunctions such as "cylinder expansion" and "internal leakage" caused by the pressure boosting effect of the vertical cylinder 40, thereby greatly improving the overall safety performance of the machine.

[0023] Furthermore, the outrigger hydraulic system also includes a first pressure sensor 71 and a second pressure sensor 72. The first pressure sensor 71 monitors the hydraulic oil pressure in the rod chamber of the vertical cylinder 40, and the second pressure sensor 72 monitors the hydraulic oil pressure in the rodless chamber of the vertical cylinder 40. The outrigger hydraulic system stops operating when the hydraulic oil pressure in the rod chamber of the vertical cylinder 40 exceeds a first set value and / or the hydraulic oil pressure in the rodless chamber of the vertical cylinder 40 exceeds a second set value. That is, when the first pressure sensor 71 detects that the hydraulic oil pressure in the rod chamber of the vertical cylinder 40 exceeds the first set value and / or the second pressure sensor 72 detects that the hydraulic oil pressure in the rodless chamber of the vertical cylinder 40 exceeds the second set value, the outrigger hydraulic system stops operating, thereby protecting the vertical cylinder 40. The first and second set values ​​can be adjusted according to the type of construction machinery to which the outrigger hydraulic system is applied, and are not limited here. When the outrigger hydraulic system is equipped with a safety valve 50, a first pressure sensor 71, and a second pressure sensor 72, the vertical cylinder 40 can be doubly protected, preventing damage to the rod chamber of the vertical cylinder 40 due to excessive hydraulic oil pressure.

[0024] Furthermore, the first and second set values ​​are less than the set value of the safety valve 50.

[0025] Since the horizontal cylinder 30 also exhibits the same problem as the vertical cylinder 40, the outrigger hydraulic system further includes a third pressure sensor 73 and a fourth pressure sensor 74. The third pressure sensor 73 monitors the hydraulic oil pressure in the rod chamber of the horizontal cylinder 30, and the fourth pressure sensor 74 monitors the hydraulic oil pressure in the rodless chamber of the horizontal cylinder 30. The outrigger hydraulic system stops operating when the hydraulic oil pressure in the rod chamber of the horizontal cylinder 30 exceeds a third set value and / or the hydraulic oil pressure in the rodless chamber of the horizontal cylinder 40 exceeds a fourth set value. Specifically, when the hydraulic oil pressure in the rod chamber of the horizontal cylinder 30 exceeds the third set value and / or the hydraulic oil pressure in the rodless chamber of the horizontal cylinder 40 exceeds the fourth set value, the outrigger hydraulic system is controlled to stop operating. These third and fourth set values ​​can be adjusted according to the type of construction machinery to which the outrigger hydraulic system is applied, and are not limited here. A third pressure sensor 73 and a fourth pressure sensor 74 are added to the rod chamber and rodless chamber of the horizontal cylinder 30. When the horizontal cylinder 30 is working, the pressure values ​​of the hydraulic oil in the rod chamber and rodless chamber of the horizontal cylinder 30 are monitored simultaneously to protect the horizontal cylinder 30 from damage caused by excessive hydraulic oil pressure.

[0026] Figure 2 yes Figure 1 For the outrigger hydraulic system's outrigger pressure signal control strategy in the event of a blockage, please refer to [link / reference needed]. Figure 2The outrigger hydraulic system also includes a PLC controller 80. The first pressure sensor 71, the second pressure sensor 72, the third pressure sensor 73, and the fourth pressure sensor 74 are all connected to the PLC controller 80. The PLC controller 80 is used to receive the hydraulic oil pressure signals monitored by the first pressure sensor 71, the second pressure sensor 72, the third pressure sensor 73, and the fourth pressure sensor 74, and to control whether the outrigger hydraulic system stops working based on the received hydraulic oil pressure signals.

[0027] Existing technology only installs one pressure sensor in the rodless chamber of the vertical cylinder or in the oil circuit connected to the rodless chamber of the vertical cylinder to monitor the hydraulic oil pressure. The PLC controller's processing method is relatively simple. If the pressure sensor also fails when the outrigger hydraulic system becomes blocked, the control strategy will also fail, posing a safety hazard. This invention, by simultaneously setting pressure monitoring points in the rodless and rod chambers of the horizontal cylinder 30 and the rodless and rod chambers of the vertical cylinder 40, increases the pressure signal of the outrigger hydraulic system to four monitoring points. When any pressure signal is abnormal, the outrigger hydraulic system can be unloaded or stop working, thereby greatly improving the overall safety performance of the machine.

[0028] In this embodiment, the control valve group 20 includes a first control valve 21 and a second control valve 22. The first oil port A1 and the second oil port B1 of the control valve group 20 are the two working oil ports of the first control valve 21, and the third oil port A2 and the fourth oil port B2 of the control valve group 20 are the two working oil ports of the second control valve 22. The oil inlet P of the control valve group 20 is connected to the oil inlet of the first control valve 21 and the oil inlet of the second control valve 22, respectively, and the oil return port T of the control valve group 20 is connected to the oil return port of the first control valve 21 and the oil return port of the second control valve 22, respectively.

[0029] Furthermore, the first control valve 21 and the second control valve 22 are configured such that the first control valve 21 has a first operating state and a second operating state. When the first control valve 21 is in the first operating state, the oil inlet P is connected to the second oil port B1, and the first oil port A1 is connected to the return oil port T. When the first control valve 21 is in the second operating state, the oil inlet P is connected to the first oil port A1, and the second oil port B1 is connected to the return oil port T. The second control valve 22 also has a first operating state and a second operating state. When the second control valve 22 is in the first operating state, the oil inlet P is connected to the fourth oil port B2, and the third oil port A2 is connected to the return oil port T. When the second control valve 22 is in the second operating state, the oil inlet P is connected to the third oil port A2, and the fourth oil port B2 is connected to the return oil port T.

[0030] Furthermore, both the first control valve 21 and the second control valve 22 are three-position four-way solenoid directional valves. Their respective working states can be controlled by energizing or de-energizing the electromagnets at both ends. For example, when the left electromagnet of the first control valve 21 is energized, the first control valve 21 is in the left position, which is the first working state. When the right electromagnet of the first control valve 21 is energized, the first control valve 21 is in the right position, which is the second working state.

[0031] Furthermore, the first control valve 21 also includes a third operating state. When the first control valve 21 is in the third operating state, the oil inlet P, the oil return T, the first oil port A1, and the second oil port B1 are disconnected from each other. The second control valve 21 also includes a third operating state. When the second control valve 22 is in the third operating state, the oil inlet P is disconnected, and the third oil port A2 and the fourth oil port B2 are both connected to the oil return port T.

[0032] In construction machinery, especially large construction machinery, due to transportation needs, the hydraulic lines of outriggers and other components are widely connected to the main hydraulic system using quick-connect couplings for easy transport. A quick-connect coupling is a tool-free connector that allows for connection or disconnection of pipelines. It has a male and a female end; when assembled, they connect the hydraulic lines, and releasing them quickly disconnects the lines. In this embodiment, the outrigger hydraulic system also includes a first quick-connect coupling 91 and a second quick-connect coupling 92. The first quick-connect coupling 91 is located on the oil inlet P of the control valve assembly 20, connecting to the main oil circuit. The second quick-connect coupling 92 is located on the oil return port T of the control valve assembly 20, connecting to the return oil circuit. When the second quick-connect coupling 92 becomes blocked, the hydraulic oil pressure in the second oil circuit 102 and the rod chamber of the vertical cylinder 40 will rapidly increase. However, this is not the only cause of increased hydraulic oil pressure; problems with other components can also lead to blockages and increased hydraulic oil pressure.

[0033] This invention also relates to an engineering machine, including the aforementioned outrigger hydraulic system. Other structures of the engineering machine are well known to those skilled in the art and will not be described in detail here.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. 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 present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A hydraulic system for an outrigger, comprising a control valve assembly (20), a horizontal cylinder (30), and a vertical cylinder (40), characterized in that, It also includes a safety valve (50) and a two-way hydraulic lock (60). The control valve assembly (20) has an inlet port P, a return port T, a first port A1, a second port B1, and a third port A2. The inlet port P is connected to the main oil circuit, and the return port T is connected to the return oil circuit. The first port A1 is connected to the rod chamber of the horizontal cylinder (30), the second port B1 is connected to the rodless chamber of the horizontal cylinder (30), the third port A2 is connected to the rodless chamber of the vertical cylinder (40) through the first oil circuit (101), and the fourth port B2 is connected to the rod chamber of the vertical cylinder (40) through the second oil circuit (102). The two-way hydraulic lock (60) includes a first hydraulically controlled check valve (61) and a second hydraulically controlled check valve (62). The first hydraulic check valve (61) is installed on the first oil circuit (101), and the second hydraulic check valve (62) is installed on the second oil circuit (102). The inlet of the safety valve (50) is connected to the oil circuit between the second hydraulic check valve (62) and the rod chamber of the vertical cylinder (40), and the outlet of the safety valve (50) is connected to the return oil circuit. The safety valve (50) is integrated on one side of the bidirectional hydraulic lock (60) and close to the rod chamber of the vertical cylinder (40). It also includes a first pressure sensor (71) and a second pressure sensor (72). The first pressure sensor (71) is used to monitor the hydraulic oil pressure in the rod chamber of the vertical cylinder (40), and the second pressure sensor... (72) A hydraulic system for monitoring the hydraulic oil pressure in the rodless chamber of the vertical cylinder (40) stops operating when the hydraulic oil pressure in the rod chamber of the vertical cylinder (40) exceeds a first set value and / or the hydraulic oil pressure in the rodless chamber of the vertical cylinder (40) exceeds a second set value, wherein both the first set value and the second set value are less than the set value of the safety valve (50); the system also includes a third pressure sensor (73) and a fourth pressure sensor (74), wherein the third pressure sensor (73) is used to monitor the hydraulic oil pressure in the rod chamber of the horizontal cylinder (30), and the fourth pressure sensor (74) is used to monitor the hydraulic oil pressure in the rodless chamber of the horizontal cylinder (30); the hydraulic system for monitoring the hydraulic oil pressure in the rodless chamber of the horizontal cylinder (30) stops operating when the hydraulic oil pressure in the rod chamber of the vertical cylinder (40) exceeds a first set value and / or the hydraulic oil pressure in the rodless chamber of the vertical cylinder (40) exceeds a second set value, wherein the first set value and the second set value are both less than the set value of the safety valve (50); the system also includes a third pressure sensor (73) and a fourth pressure sensor (74), wherein the third pressure sensor (73) is used to monitor the hydraulic oil pressure in the rod chamber of the horizontal cylinder (30), and the fourth pressure sensor (74) is used to monitor the hydraulic oil pressure in the rodless chamber of the horizontal cylinder (30); the system for monitoring the hydraulic oil pressure in the rodless chamber of the horizontal cylinder (40) stops operating when the hydraulic oil pressure in the rod chamber of the vertical cylinder (40) exceeds a second set value, wherein the hydraulic oil pressure in the rodless ... The system stops working when the hydraulic oil pressure in the rod chamber of the cylinder (30) exceeds a third set value and / or the hydraulic oil pressure in the rodless chamber of the horizontal cylinder (30) exceeds a fourth set value; it also includes a PLC controller (80), wherein the first pressure sensor (71), the second pressure sensor (72), the third pressure sensor (73) and the fourth pressure sensor (74) are all connected to the PLC controller (80), and the PLC controller (80) is used to receive the hydraulic oil pressure signals monitored by the first pressure sensor (71), the second pressure sensor (72), the third pressure sensor (73) and the fourth pressure sensor (74) and control whether the outrigger hydraulic system stops working according to the received hydraulic oil pressure signals.

2. The outrigger hydraulic system as described in claim 1, characterized in that, The safety valve (50) is a pressure relief valve.

3. The outrigger hydraulic system as described in claim 1, characterized in that, The control valve group (20) includes a first control valve (21) and a second control valve (22). The first oil port A1 and the second oil port B1 of the control valve group (20) are the two working oil ports of the first control valve (21). The third oil port A2 and the fourth oil port B2 of the control valve group (20) are the two working oil ports of the second control valve (22). The oil inlet P of the control valve group (20) is connected to the oil inlet of the first control valve (21) and the oil inlet of the second control valve (22), respectively. The oil return port T of the control valve group (20) is connected to the oil return port of the first control valve (21) and the oil return port of the second control valve (22), respectively.

4. The outrigger hydraulic system as described in claim 3, characterized in that, The first control valve (21) has a first working state and a second working state. When the first control valve (21) is in the first working state, the oil inlet P is connected to the second oil inlet B1, and the first oil inlet A1 is connected to the oil return port T. When the first control valve (21) is in the second working state, the oil inlet P is connected to the first oil inlet A1, and the second oil inlet B1 is connected to the oil return port T. The second control valve (22) has a first working state and a second working state. When the second control valve (22) is in the first working state, the oil inlet P is connected to the fourth oil inlet B2, and the third oil inlet A2 is connected to the oil return port T. When the second control valve (22) is in the second working state, the oil inlet P is connected to the third oil inlet A2, and the fourth oil inlet B2 is connected to the oil return port T.

5. The outrigger hydraulic system as described in claim 3, characterized in that, The outrigger hydraulic system also includes a first quick connector (91) and a second quick connector (92). The first quick connector (91) is located on the oil line from the oil inlet P of the control valve group (20) to the main oil line, and the second quick connector (92) is located on the oil line from the oil return port T of the control valve group (20) to the return oil line.

6. An engineering machinery, characterized in that, Includes the outrigger hydraulic system as described in any one of claims 1 to 5.

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