Multifunctional leveling system supporting leg electro-hydraulic actuator device

Abstract

The invention provides a multifunctional leveling system supporting leg electro-hydraulic actuator device, which relates to the field of electro-hydraulic control, and comprises a hydraulic actuating mechanism, a hydraulic power unit and a mechanical locking mechanism, a valve block in the hydraulic power unit is matched with the surface of the hydraulic actuating mechanism, oil ports of the valve block respectively correspond to container oil ports of the hydraulic actuating mechanism, and the mechanical locking mechanism is connected with the hydraulic actuating mechanism. The hydraulic power unit is communicated with the hydraulic actuating mechanism, and a base of the mechanical locking mechanism is fixedly connected to a shell of the hydraulic actuating mechanism; the hydraulic executing mechanism comprises a displacement sensor, a piston rod and an asymmetric hydraulic oil cylinder, the displacement sensor is arranged in the asymmetric hydraulic oil cylinder, the asymmetric hydraulic oil cylinder is in driving connection with the piston rod, the piston rod is slidably connected into the mechanical locking mechanism, and the position of the piston rod is detected through the displacement sensor. Module integration design is adopted, the leakage and leakage probability is greatly reduced, maintenance is convenient, the in-situ maintaining function is achieved, the piston rod of the hydraulic executing mechanism can be kept in situ under the abnormal working condition, and equipment safety is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of electro-hydraulic control, and in particular to an electro-hydraulic actuator device for a supporting leg of a multifunctional leveling system. Background Art

[0002] The leveling system uses valve-controlled hydraulic cylinders, electric cylinders or hydraulic motor-driven screws as supporting power devices. Traditional valve-controlled hydraulic cylinders are complex to control and difficult to lay pipes. They require a separate hydraulic station, occupy a large space, have low system efficiency, and have serious leakage, making maintenance very inconvenient. The electric cylinder support legs have weak impact resistance, low system efficiency, and have a large weight under the same thrust capacity. Wear or deformation of the screw threads will cause jamming.

[0003] After searching, there is a Chinese invention patent with patent number CN105041390A, which discloses an integrated electro-hydraulic actuator type steam turbine valve adjustment system. The main points are: it includes a lever, a valve and an integrated electro-hydraulic actuator, the integrated electro-hydraulic actuator is fixed in the bracket, the upper end of the bracket is fixed with a guide support plate, the piston rod of the integrated electro-hydraulic actuator passes through the guide hole in the center of the guide support plate, the lower end of the bracket is installed on the base through a hinge shaft, the upper end of the piston rod of the integrated electro-hydraulic actuator is hinged with the power point of the lever, and all the above hinge shafts are in the same direction. The above patents do not solve the problems of inconvenient maintenance; the electric cylinder support legs have weak impact resistance, low system efficiency, and large weight under the same thrust capacity. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a multifunctional leveling system support leg electro-hydraulic actuator device.

[0005] A multifunctional leveling system support leg electro-hydraulic actuator device provided by the present invention comprises: a hydraulic actuator, a hydraulic power unit and a mechanical locking mechanism, wherein a valve block in the hydraulic power unit matches with a surface of the hydraulic actuator, and an oil port of the valve block corresponds to a container oil port of the hydraulic actuator, so that the hydraulic power unit is connected to the hydraulic actuator, and a base of the mechanical locking mechanism is fixedly connected to a housing of the hydraulic actuator;

[0006] The hydraulic actuator includes a displacement sensor, a piston rod and an asymmetric hydraulic cylinder. The displacement sensor is built into the asymmetric hydraulic cylinder. The asymmetric hydraulic cylinder is driven and connected to the piston rod. The piston rod is slidably connected to the mechanical locking mechanism. The position of the piston rod is detected by the displacement sensor.

[0007] Preferably, the hydraulic power unit comprises an oil tank, a motor, a bidirectional hydraulic pump, a filter element and a valve block, one end of the valve block is connected to the oil tank, the other end of the valve block is connected to the motor, the bottom of the valve block is connected to a mechanical locking mechanism, and the hydraulic power unit is connected to the hydraulic actuator through the valve block;

[0008] The fuel tank is respectively connected to a two-way hydraulic pump, a filter element, and a hydraulic actuator. The two-way hydraulic pump is connected to a motor, and the two-way hydraulic pump, the filter element, and the valve block are connected in parallel;

[0009] Preferably, a first overflow valve and a shuttle valve are sequentially connected between the fuel tank and the two-way hydraulic pump. One end of the shuttle valve is connected to a first hydraulic control check valve and a third hydraulic control check valve, and the other end of the shuttle valve is connected to a second hydraulic control check valve and a fourth hydraulic control check valve. The first hydraulic control check valve and the second hydraulic control check valve are respectively connected to the filter element. The third hydraulic control check valve is respectively connected to a second overflow valve and the hydraulic actuator, and a first oil pressure sensor is connected between the second overflow valve and the hydraulic actuator. The fourth hydraulic control check valve is respectively connected to a third overflow valve and the hydraulic actuator, and a second oil pressure sensor is connected between the third overflow valve and the hydraulic actuator.

[0010] Preferably, the mechanical locking mechanism includes a one-way valve, an accumulator, a fifth hydraulic control check valve, a locking mechanism, and a hydraulic valve. A one-way valve is connected between the first overflow valve and the shuttle valve. The one-way valve is connected between the accumulator and the fifth hydraulic control check valve. The fifth hydraulic control check valve is connected to the hydraulic valve, and the hydraulic valve is connected to the locking mechanism.

[0011] Preferably, the locking mechanism includes a base, a piston, a tapered sleeve, a disc spring, and a hollow tapered block. One end of the hollow tapered block is connected to the disc spring, the other end of the hollow tapered block is connected to the piston, the hollow tapered block is sleeved in the tapered sleeve, the tapered sleeve is connected in the base, and the base is fixedly connected to the housing of the hydraulic actuator;

[0012] The high-pressure hydraulic oil in the accumulator pushes the piston to move, and the piston pushes the hollow tapered block to move. The hollow tapered block compresses the disc spring, so that the locking force between the hollow tapered block and the piston rod of the hydraulic actuator is released.

[0013] Preferably, when the motor is working, the high-pressure hydraulic oil in the two-way hydraulic pump opens the fifth hydraulic control check valve and the hydraulic valve through the shuttle valve. The high-pressure hydraulic oil in the accumulator pushes the piston to move, so that the locking force between the hollow tapered block and the piston rod of the hydraulic actuator is released;

[0014] After the piston rod reaches the target position, the motor stops rotating. The two-way hydraulic pump notifies the common part, the third hydraulic control check valve and the fourth hydraulic control check valve close, and the piston rod remains in place.

[0015] Preferably, the high-pressure hydraulic oil in the two-way hydraulic pump enters the cavity of the hydraulic actuator through the third hydraulic control check valve or the fourth hydraulic control check valve, pushes the piston rod to move, and the position of the piston rod is detected by a displacement sensor. The first oil pressure sensor and the second oil pressure sensor respectively detect the pressure in the corresponding cavity in the hydraulic actuator.

[0016] Preferably, when the bi-directional hydraulic pump stops supplying oil, the outlet pressure of the bi-directional hydraulic pump decreases, the outlet pressure of the shuttle valve decreases, the fifth hydraulic check valve closes, the hydraulic valve connects the locking device to the oil circuit of the fuel tank, the force exerted by the piston on the hollow cone block decreases, the disc spring pushes the hollow cone block to move, and under the action of the cone sleeve, the hollow cone block clamps the piston rod, and the piston rod of the hydraulic actuator is locked.

[0017] Preferably, a first cavity and a second cavity are provided in the hydraulic actuator, the first cavity is connected to a second overflow valve, and the second cavity is connected to a third overflow valve;

[0018] When the first oil pressure sensor detects that the pressure in the first cavity is greater than the opening pressure of the second overflow valve, the first cavity is depressurized;

[0019] When the second oil pressure sensor detects that the pressure in the second cavity is greater than the opening pressure of the third overflow valve, the second cavity is depressurized.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention adopts a modular integrated design, and the oil circuit is a closed system without external pipelines, greatly reducing the probability of leakage in the support leg electro-hydraulic actuator and facilitating maintenance;

[0022] (2) The present invention adopts a hydraulic lock composed of hydraulic check valves, and the system has an in-situ holding function. Under abnormal conditions, the piston rod of the hydraulic actuator can maintain its in-situ position, ensuring the safety of the equipment; and through the mechanical locking device, the piston rod of the support leg electro-hydraulic actuator can be locked for a long time without settlement, having the function of maintaining the pose of the leveling platform for a long time;

[0023] (3) The present invention adopts built-in displacement sensors and oil pressure sensors, having the functions of detecting virtual legs and limiting the extreme positions. By detecting the oil pressure of the hydraulic actuator through the pressure sensor, it can be judged whether the support leg touches the ground; by detecting the position of the support leg through the displacement sensor, it can be judged whether the remaining stroke of the support leg electro-hydraulic actuator meets the leveling requirements and whether it reaches the extreme position of the piston rod stroke. At the same time, it provides the support leg position parameters for the control algorithm, improving the leveling accuracy;

[0024] (4) The present invention adopts an overflow valve for the hydraulic cylinder cavity, enabling the safety protection function of the hydraulic actuator under wide-range temperature shock conditions. Under wide-range temperature shock, the thermal expansion and contraction of the working medium of the support leg electro-hydraulic actuator will affect the performance of the electro-hydraulic actuator and even cause damage to the hydraulic actuator. The system has the function of protecting the system under wide-range temperature shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0026] Figure 1 is the hydraulic schematic diagram of the present invention;

[0027] Figure 2 is the overall structural schematic diagram of the present invention;

[0028] Figure 3 is the structural schematic diagram of the locking mechanism in the present invention.

[0029] As shown in the figure: First overflow valve - 1; Oil tank - 2; Shuttle valve - 3; Check valve - 4; Accumulator - 5; Fifth hydraulic control check valve - 6; Motor - 7; Bidirectional hydraulic pump - 8; Locking mechanism - 9; Hydraulic valve - 10; Filter element - 11; First hydraulic control check valve - 12; Second hydraulic control check valve - 13; Third hydraulic control check valve - 14; Fourth hydraulic control check valve - 15; First oil pressure sensor - 16; Second oil pressure sensor - 17; Second overflow valve - 18; Third overflow valve - 19; Hydraulic actuator - 20; Displacement sensor - 21; Valve block - 22; Hydraulic power unit - 23; Mechanical locking mechanism - 24; Base - 25; Piston - 26; Taper sleeve - 27; Disc spring - 28; Hollow cone block - 29. Detailed implementation mode

[0030] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0031] Example 1

[0032] According to a multi-functional leveling system support leg electro-hydraulic actuator device provided by the present invention, as Figures 1-3 shown, it includes: a hydraulic actuator 20, a hydraulic power unit 23, and a mechanical locking mechanism 24. The valve block 22 in the hydraulic power unit 23 is in surface contact with the hydraulic actuator 20, and the oil ports of the valve block 22 correspond to the container oil ports of the hydraulic actuator 20 respectively, realizing the connection between the hydraulic power unit 23 and the hydraulic actuator 20, and the base of the mechanical locking mechanism 24 is fixedly connected to the housing of the hydraulic actuator 20; the hydraulic actuator 20 includes a displacement sensor 21, a piston rod, and an asymmetric hydraulic cylinder. The displacement sensor 21 is built into the asymmetric hydraulic cylinder, the asymmetric hydraulic cylinder is drivingly connected with the piston rod, the piston rod is slidably connected in the mechanical locking mechanism 24, and the position of the piston rod is detected by the displacement sensor 21.

[0033] The hydraulic power unit 23 includes an oil tank 2, a motor 7, a bi-directional hydraulic pump 8, a filter element 11 and a valve block 22. One end of the valve block 22 is connected to the oil tank 2, the other end of the valve block 22 is connected to the motor 7, the bottom of the valve block 22 is connected to a mechanical locking mechanism 24, and the hydraulic power unit 23 is communicated with a hydraulic actuator 20 through the valve block 22; the oil tank 2 is respectively connected to the bi-directional hydraulic pump 8, the filter element 11 and the hydraulic actuator 20, the bi-directional hydraulic pump 8 is connected to the motor 7, and the bi-directional hydraulic pump 8, the filter element 11 and the valve block 22 are connected in parallel. A first overflow valve 1 and a shuttle valve 3 are sequentially connected between the oil tank 2 and the bi-directional hydraulic pump 8. One end of the shuttle valve 3 is connected to a first pilot-operated check valve 12 and a third pilot-operated check valve 14, the other end of the shuttle valve 3 is connected to a second pilot-operated check valve 13 and a fourth pilot-operated check valve 15. The first pilot-operated check valve 12 and the second pilot-operated check valve 13 are respectively connected to the filter element 11, the third pilot-operated check valve 14 is respectively connected to a second overflow valve 18 and the hydraulic actuator 20, and a first oil pressure sensor 16 is connected between the second overflow valve 18 and the hydraulic actuator 20. The fourth pilot-operated check valve 15 is respectively connected to a third overflow valve 19 and the hydraulic actuator 20, and a second oil pressure sensor 17 is connected between the third overflow valve 19 and the hydraulic actuator 20.

[0034] The hydraulic actuator 20 is internally provided with a first cavity and a second cavity. The first cavity is connected to the second overflow valve 18, and the second cavity is connected to the third overflow valve 19; when the first oil pressure sensor 16 detects that the pressure in the first cavity is greater than the opening pressure of the second overflow valve 18, the first cavity is depressurized; when the second oil pressure sensor 17 detects that the pressure in the second cavity is greater than the opening pressure of the third overflow valve 19, the second cavity is depressurized.

[0035] More specifically, the electro-hydraulic actuator of the support leg of the multifunctional leveling system adopts a modular integrated design, and the oil circuit is a closed system. The probability of leakage of the electro-hydraulic actuator of the support leg is greatly reduced, which is convenient for maintenance. By adopting the pilot-operated check valve 14 and the pilot-operated check valve 15, the system has an in-situ holding function, and the piston rod of the hydraulic actuator 20 can maintain its in-situ position under abnormal working conditions, ensuring the safety of the equipment.

[0036] By adopting the built-in displacement sensor 21, the oil pressure sensor 16 and the oil pressure sensor 17, it has the functions of detecting virtual legs and limiting the extreme position. By detecting with the pressure sensor 16, it can be judged whether the support leg touches the ground. By detecting the position of the piston rod of the hydraulic actuator 20 with the displacement sensor 21, it can be judged whether the remaining stroke of the electro-hydraulic actuator meets the leveling requirements. The mechanical locking device 19 can realize the long-term locking of the piston rod of the electro-hydraulic actuator of the support leg without settlement, and realize the function of maintaining the pose of the leveling system for a long time.

[0037] The hydraulic cylinder cavity of the hydraulic actuator 20 is internally provided with an overflow valve 18 and an overflow valve 19, enabling the safety protection function of the hydraulic actuator under wide-range temperature shock conditions. Under wide-range temperature shock, the thermal expansion and contraction of the working medium of the support leg electro-hydraulic actuator will affect the performance of the electro-hydraulic actuator, and may even cause damage to the hydraulic actuator 20. The system has the function of protecting the system under wide-range temperature shock.

[0038] Example 2

[0039] This Embodiment 2 is completed on the basis of Embodiment 1, mainly further elaborating on the mechanical locking mechanism 24, such as Figure 1 and Figure 3 shown. Specifically:

[0040] The mechanical locking mechanism 24 includes a one-way valve 4, an accumulator 5, a fifth hydraulic control one-way valve 6, a locking mechanism 9, and a hydraulic valve 10. A one-way valve 4 is connected between the first overflow valve 1 and the shuttle valve 3. The one-way valve 4 is connected between the accumulator 5 and the fifth hydraulic control one-way valve 6. The fifth hydraulic control one-way valve 6 is connected to the hydraulic valve 10, and the hydraulic valve 10 is connected to the locking mechanism 9.

[0041] The locking mechanism 9 includes a base 25, a piston 26, a tapered sleeve 27, a disc spring 28, and a hollow tapered block 29. One end of the hollow tapered block 29 is connected to the disc spring 28, the other end of the hollow tapered block 29 is connected to the piston 26, the hollow tapered block 29 is sleeved inside the tapered sleeve 27, the tapered sleeve 27 is connected inside the base 25, and the base 25 is fixedly connected to the housing of the hydraulic actuator 20; to release the locking force between the hollow tapered block 29 and the piston rod of the hydraulic actuator 20.

[0042] Working principle: When the motor 7 operates, the high-pressure hydraulic oil in the double-directional hydraulic pump 8 opens the fifth hydraulic control one-way valve 6 and the hydraulic valve 10 through the shuttle valve 3. The high-pressure hydraulic oil in the accumulator 5 pushes the piston 26 to move. The piston 26 pushes the hollow tapered block 29 to move. The hollow tapered block 29 compresses the disc spring 28 to release the locking force between the hollow tapered block 29 and the piston rod of the hydraulic actuator 20. At the same time, the high-pressure hydraulic oil in the double-directional hydraulic pump 8 enters the cavity of the hydraulic actuator 20 through the third hydraulic control one-way valve 14 or the fourth hydraulic control one-way valve 15, pushing the piston rod to move, and detecting the position of the piston rod through the displacement sensor 21. The first oil pressure sensor 16 and the second oil pressure sensor 17 respectively detect the corresponding cavity pressures inside the hydraulic actuator 20. After the piston rod reaches the target position, the motor 7 stops rotating, the double-directional hydraulic pump 8 notifies the common, the third hydraulic control one-way valve 14 and the fourth hydraulic control one-way valve 15 close, and the piston rod remains in place.

[0043] Meanwhile, the two-way hydraulic pump 8 stops supplying oil, the outlet pressure of the two-way hydraulic pump 8 decreases, the outlet pressure of the shuttle valve 3 decreases, the fifth hydraulic check valve 6 closes, the hydraulic valve 10 connects the locking device 9 and the oil circuit of the fuel tank 2, the acting force of the piston 26 on the hollow cone block 29 decreases, the disc spring 28 pushes the hollow cone block 29 to move, and under the action of the cone sleeve 27, the hollow cone block 29 clamps the piston rod tightly, and the piston rod of the hydraulic actuator 20 is locked.

[0044] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0045] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A multi-functional leveling system support leg electro-hydraulic actuator device, characterized in that, Comprising: A hydraulic actuator (20), a hydraulic power unit (23), and a mechanical locking mechanism (24). The valve block (22) in the hydraulic power unit (23) is in surface contact with the hydraulic actuator (20). The oil ports of the valve block (22) correspond to the container oil ports of the hydraulic actuator (20) respectively, so as to connect the hydraulic power unit (23) with the hydraulic actuator (20). And the base of the mechanical locking mechanism (24) is fixedly connected to the housing of the hydraulic actuator (20). The hydraulic actuator (20) includes a displacement sensor (21), a piston rod, and an asymmetric hydraulic cylinder. The displacement sensor (21) is built into the asymmetric hydraulic cylinder. The asymmetric hydraulic cylinder is drivingly connected to the piston rod. The piston rod is slidably connected within the mechanical locking mechanism (24), and the position of the piston rod is detected by the displacement sensor (21).

2. The electro-hydraulic actuator device for the support leg of the multi-functional leveling system according to claim 1, characterized in that, The hydraulic power unit (23) includes an oil tank (2), a motor (7), a bi-directional hydraulic pump (8), a filter element (11), and a valve block (22). One end of the valve block (22) is connected to the oil tank (2), the other end of the valve block (22) is connected to the motor (7), the bottom of the valve block (22) is connected to the mechanical locking mechanism (24), and the hydraulic power unit (23) is connected to the hydraulic actuator (20) through the valve block (22). The oil tank (2) is respectively connected to the bi-directional hydraulic pump (8), the filter element (11), and the hydraulic actuator (20). The bi-directional hydraulic pump (8) is connected to the motor (7), and the bi-directional hydraulic pump (8), the filter element (11), and the valve block (22) are connected in parallel.

3. The electro-hydraulic actuator device for the support leg of the multi-functional leveling system according to claim 2, characterized in that, A first overflow valve (1) and a shuttle valve (3) are sequentially connected between the oil tank (2) and the bi-directional hydraulic pump (8). One end of the shuttle valve (3) is connected to a first hydraulic control one-way valve (12) and a third hydraulic control one-way valve (14). The other end of the shuttle valve (3) is connected to a second hydraulic control one-way valve (13) and a fourth hydraulic control one-way valve (15). The first hydraulic control one-way valve (12) and the second hydraulic control one-way valve (13) are respectively connected to the filter element (11). The third hydraulic control one-way valve (14) is respectively connected to a second overflow valve (18) and the hydraulic actuator (20), and a first oil pressure sensor (16) is connected between the second overflow valve (18) and the hydraulic actuator (20). The fourth hydraulic control one-way valve (15) is respectively connected to a third overflow valve (19) and the hydraulic actuator (20), and a second oil pressure sensor (17) is connected between the third overflow valve (19) and the hydraulic actuator (20).

4. The electro-hydraulic actuator device for the support leg of the multi-functional leveling system according to claim 3, characterized in that, The mechanical locking mechanism (24) includes a one-way valve (4), an accumulator (5), a fifth pilot-operated check valve (6), a locking mechanism (9), and a hydraulic valve (10). The one-way valve (4) is connected between the first relief valve (1) and the shuttle valve (3). The one-way valve (4) is connected between the accumulator (5) and the fifth pilot-operated check valve (6). The fifth pilot-operated check valve (6) is connected to the hydraulic valve (10), and the hydraulic valve (10) is connected to the locking mechanism (9).

5. The electro-hydraulic actuator device for the support leg of the multi-functional leveling system according to claim 4, characterized in that, The locking mechanism (9) includes a base (25), a piston (26), a tapered sleeve (27), a disc spring (28), and a hollow tapered block (29). One end of the hollow tapered block (29) is connected to the disc spring (28), and the other end of the hollow tapered block (29) is connected to the piston (26). The hollow tapered block (29) is sleeved inside the tapered sleeve (27), and the tapered sleeve (27) is connected inside the base (25). The base (25) is fixedly connected to the housing of the hydraulic actuator (20). The high-pressure hydraulic oil in the accumulator (5) pushes the piston (26) to move. The piston (26) pushes the hollow tapered block (29) to move. The hollow tapered block (29) compresses the disc spring (28), so that the locking force between the hollow tapered block (29) and the piston rod of the hydraulic actuator (20) is released.

6. The electro-hydraulic actuator device of the support leg of the multifunctional leveling system according to claim 5, characterized in that, When the motor (7) works, the high-pressure hydraulic oil in the bi-directional hydraulic pump (8) opens the fifth pilot-operated check valve (6) and the hydraulic valve (10) through the shuttle valve (3). The high-pressure hydraulic oil in the accumulator (5) pushes the piston (26) to move, so that the locking force between the hollow tapered block (29) and the piston rod of the hydraulic actuator (20) is released. After the piston rod reaches the target position, the motor (7) stops rotating. The bi-directional hydraulic pump (8) notifies the common part. The third pilot-operated check valve (14) and the fourth pilot-operated check valve (15) close, and the piston rod stays in place.

7. The electro-hydraulic actuator device of the support leg of the multifunctional leveling system according to claim 6, characterized in that, The high-pressure hydraulic oil in the bi-directional hydraulic pump (8) enters the cavity of the hydraulic actuator (20) through the third pilot-operated check valve (14) or the fourth pilot-operated check valve (15), pushes the piston rod to move, and the position of the piston rod is detected by the displacement sensor (21). The first oil pressure sensor (16) and the second oil pressure sensor (17) respectively detect the cavity pressures corresponding in the hydraulic actuator (20).

8. The electro-hydraulic actuator device of the support leg of the multifunctional leveling system according to claim 7, characterized in that, When the bi-directional hydraulic pump (8) stops supplying oil, the outlet pressure of the bi-directional hydraulic pump (8) decreases, the outlet pressure of the shuttle valve (3) decreases, the fifth pilot-operated check valve (6) closes, the hydraulic valve (10) connects the locking device (9) to the oil circuit of the fuel tank (2). The acting force of the piston (26) on the hollow tapered block (29) decreases. The disc spring (28) pushes the hollow tapered block (29) to move. Under the action of the tapered sleeve (27), the hollow tapered block (29) clamps the piston rod, and the piston rod of the hydraulic actuator (20) is locked.

9. The electro-hydraulic actuator device for the support leg of the multifunctional leveling system according to claim 8, characterized in that, The hydraulic actuator (20) is provided with a first cavity and a second cavity. The first cavity is connected to the second overflow valve (18), and the second cavity is connected to the third overflow valve (19). When the first oil pressure sensor (16) detects that the pressure in the first cavity is higher than the opening pressure of the second overflow valve (18), the first cavity is depressurized. When the second oil pressure sensor (17) detects that the pressure in the second cavity is higher than the opening pressure of the third overflow valve (19), the second cavity is depressurized.

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