Hydraulic steering device of engineering operation vehicle

Abstract

The utility model provides a hydraulic steering device of an engineering operation vehicle, which relates to the technical field of steering devices and comprises an oil source, a steering driving unit, an electric control hydraulic unit and a steering wheel steering gear. Wherein the oil source is used for providing pressure oil. The steering driving unit comprises a first hydraulic driving element and a second hydraulic driving element, the first hydraulic driving element is used for driving the rear wheels to steer, and the second hydraulic driving element is used for driving the front wheels to steer. The electric control hydraulic unit comprises a steering electromagnetic valve and a remote controller used for controlling the steering electromagnetic valve to act. The steering electromagnetic valve is arranged between the oil source and the steering driving unit and used for controlling the steering driving unit to achieve steering. The steering wheel steering gear is arranged between the oil source and the steering driving unit and used for controlling the steering driving unit to achieve steering according to steering operation of a steering wheel. According to the technical scheme, the novel hydraulic steering device is provided for the engineering operation vehicle, and the steering control mode of the novel hydraulic steering device is more flexible.

Description

Technical Field

[0001] The present application relates to the technical field of steering devices, and in particular to a hydraulic steering device for an engineering vehicle. Background Art

[0002] Engineering vehicles can be used for transportation, excavation, and repair. They are usually equipped with various types of working arms to perform various tasks. They can be used in municipal operations in old cities, mine operations, railway construction, subway construction, etc. Common engineering vehicles include large cranes, excavators, bulldozers, rollers, loaders, power repair vehicles, and engineering rescue vehicles.

[0003] Under normal operating conditions, engineering vehicles use manual steering wheels to steer, which requires the driver to operate in the cab and cannot be remotely controlled. Under some working conditions, it is inconvenient to use a steering wheel to control the direction of the engineering vehicle. Utility Model Content

[0004] The technical problem to be solved by the present application is to propose a hydraulic steering device for an engineering vehicle in view of the above-mentioned deficiencies of the prior art.

[0005] A hydraulic steering device for an engineering vehicle, comprising:

[0006] An oil source, for providing pressurized oil;

[0007] A steering drive unit, comprising a first hydraulic drive element and a second hydraulic drive element, wherein the first hydraulic drive element is used to drive the rear wheel steering, and the second hydraulic drive element is used to drive the front wheel steering;

[0008] The electronically controlled hydraulic unit includes a steering solenoid valve and a remote controller for controlling the movement of the steering solenoid valve; the steering solenoid valve is arranged between the oil source and the steering drive unit, and is used to control the steering drive unit to achieve steering;

[0009] The steering wheel steering gear is arranged between the oil source and the steering drive unit, and is used to control the steering drive unit to achieve steering according to the steering operation of the steering wheel.

[0010] Optionally, the electronically controlled hydraulic unit and the steering wheel steering gear are connected in parallel between the oil source and the steering drive unit.

[0011] Optionally, the steering drive unit is provided with a first oil circuit and a second oil circuit, one of which is used to input pressure oil and the other is used to return oil, and the oil flow directions in the first oil circuit and the second oil circuit correspond to the driving directions of the first hydraulic drive element and the second hydraulic drive element;

[0012] The two working oil ports on the output side of the steering solenoid valve are connected to the first oil circuit and the second oil circuit respectively; the two working oil ports of the steering wheel steering gear are connected to the first oil circuit and the second oil circuit respectively.

[0013] Optionally, the steering solenoid valve is an electromagnetic reversing valve, which is used to switch the flow direction of oil in the first oil circuit and the second oil circuit.

[0014] Optionally, the electronically controlled hydraulic unit further includes an electronically controlled switching valve and a shuttle valve;

[0015] The two oil inlets of the shuttle valve are respectively connected to the two working oil ports on the output side of the steering solenoid valve;

[0016] The oil source comprises an oil source valve, and the oil source valve is provided with a control oil port, through which the output of the oil source is controlled;

[0017] The electronically controlled switching valve is respectively connected to the oil outlet of the shuttle valve, the pressure feedback oil port of the steering wheel gear, and the control oil port of the oil source valve; the electronically controlled switching valve is a reversing valve and is provided with a first working position and a second working position. When the valve core of the electronically controlled switching valve is switched to the first working position, the control oil port of the control oil source valve is connected to the oil outlet of the shuttle valve, and the control oil port of the control oil source valve is not connected to the pressure feedback oil port of the steering wheel gear; when the valve core of the electronically controlled switching valve is switched to the second working position, the control oil port of the control oil source valve is not connected to the oil outlet of the shuttle valve, and the control oil port of the control oil source valve is connected to the pressure feedback oil port of the steering wheel gear.

[0018] Optionally, the first hydraulic drive element and the second hydraulic drive element are both double-piston-rod hydraulic cylinders; wherein the first hydraulic drive element corresponds to a first double-piston-rod hydraulic cylinder, and the second hydraulic drive element corresponds to a second double-piston-rod hydraulic cylinder;

[0019] The first double-piston-rod hydraulic cylinder is arranged between the two rear wheels, and the piston rods on both sides thereof respectively drive the steering of the rear wheels on both sides; the second double-piston-rod hydraulic cylinder is arranged between the two front wheels, and the piston rods on both sides thereof respectively drive the steering of the front wheels on both sides; the piston rods of the first double-piston-rod hydraulic cylinder and the second double-piston-rod hydraulic cylinder can move in the same direction or in opposite directions to drive the front wheels and the rear wheels to rotate in the same direction or in opposite directions.

[0020] Optionally, the steering drive unit further comprises a steering mode switching valve, wherein the steering mode switching valve is arranged between the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder;

[0021] The steering mode switching valve is an electromagnetic reversing valve, which has at least a first working position and a second working position. When its valve core is located in the first working position, the piston rods of the first double-piston-rod hydraulic cylinder and the second double-piston-rod hydraulic cylinder move in the same direction. When its valve core is located in the second working position, the piston rods of the first double-piston-rod hydraulic cylinder and the second double-piston-rod hydraulic cylinder move in the opposite direction.

[0022] Optionally, the steering mode switching valve further has a third working position. When the valve core is located at the third working position, the first double-piston-rod hydraulic cylinder acts alone, and the second double-piston-rod hydraulic cylinder remains stationary.

[0023] Optionally, a bidirectional hydraulic lock is further provided between the steering mode switching valve and the second double-piston rod hydraulic cylinder.

[0024] Optionally, the remote controller is a wireless controller, which can be used to control the actions of all solenoid valves.

[0025] The technical solution of the present application is provided with an electronically controlled hydraulic unit and a steering wheel steering gear, and the electronically controlled hydraulic unit can be used for remote control steering, or the steering wheel steering gear can be used to manually turn the steering wheel for steering. When it is inconvenient to turn the steering wheel, the electronically controlled hydraulic unit can be used for remote control steering, and the steering control is more flexible and can adapt to more working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the hydraulic steering device of the engineering work vehicle in the embodiment of the present application.

[0027] Figure 2 It is a schematic block diagram of a hydraulic steering device of an engineering work vehicle in an embodiment of the present application.

[0028] Figure 3 It is a schematic diagram of the arrangement of the first hydraulic drive element and the second hydraulic drive element in an embodiment of the present application.

[0029] Figure numerals: oil source 10, oil source valve 11, steering drive unit 20, first hydraulic drive element 21, second hydraulic drive element 22, first oil circuit 23, second oil circuit 24, steering mode switching valve 25, two-way hydraulic lock 26, electronically controlled hydraulic unit 30, steering solenoid valve 31, remote control 32, electronically controlled switching valve 33, shuttle valve 34, steering wheel steering gear 40. DETAILED DESCRIPTION

[0030] The following is the specific embodiment of the present application and in conjunction with the accompanying drawings, the technical scheme of the present application is further described, but the present application is not limited to these embodiments. In the following description, specific details such as specific configuration and assembly are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures has been omitted.

[0031] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other.

[0032] The embodiment of the present application provides a hydraulic steering device for an engineering vehicle, which is provided with an electronically controlled hydraulic unit and a steering wheel steering gear. The electronically controlled hydraulic unit can be used for remote control steering, or the steering wheel steering gear can be used to manually turn the steering wheel for steering. When it is inconvenient to turn the steering wheel for steering, the electronically controlled hydraulic unit can be used for remote control steering, which improves the convenience of use and can be adapted to more working conditions. The hydraulic steering device is described in detail below in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, the hydraulic steering device of the engineering vehicle includes an oil source 10, a steering drive unit 20, an electronically controlled hydraulic unit 30, and a steering wheel steering gear 40. The oil source 10 is used to provide pressurized oil. The steering drive unit 20 includes a first hydraulic drive element 21 and a second hydraulic drive element 22. The first hydraulic drive element 21 is used to drive the rear wheel steering, and the second hydraulic drive element 22 is used to drive the front wheel steering. The electronically controlled hydraulic unit 30 includes a steering solenoid valve 31 and a remote controller 32. The remote controller 32 is used to control the action of the steering solenoid valve 31. The steering solenoid valve 31 is arranged between the oil source 10 and the steering drive unit 20, and is used to control the steering drive unit 20 to achieve steering. The steering wheel steering gear 40 is arranged between the oil source 10 and the steering drive unit 20, and is used to control the steering drive unit 20 to achieve steering according to the steering operation of the steering wheel.

[0034] The oil source 10 provides pressurized oil to the steering drive unit 20 to drive the steering drive unit 20 to work. Figure 3 As shown, the chassis of the engineering vehicle is provided with a front axle and a rear axle, the first hydraulic drive element 21 is arranged on the rear axle of the engineering vehicle, and is used to drive the rear wheel B to steer, and the second hydraulic drive element 22 is arranged on the front axle of the engineering vehicle, and is used to drive the front wheel A to steer. In a specific example, the first hydraulic drive element 21 and the second hydraulic drive element 22 are both double-piston rod hydraulic cylinders, such as Figure 3As shown, the first hydraulic drive element 21 is arranged between the two rear wheels B, and the second hydraulic drive element 22 is arranged between the two front wheels A.

[0035] Furthermore, an electronically controlled hydraulic unit 30 and a steering wheel steering gear 40 are arranged between the oil source 10 and the steering drive unit 20. The steering wheel steering gear 40 is used to control the steering drive unit 20 to achieve steering according to the steering operation of the steering wheel. The electronically controlled hydraulic unit 30 is equipped with a remote controller 32, and the steering solenoid valve 31 is operated by the remote controller 32 to operate. The steering solenoid valve 31 controls the steering drive unit 20 to achieve steering according to the control signal sent by the remote controller 32. When in use, the steering control of the engineering vehicle can be performed through the electronically controlled hydraulic unit 30 or the steering wheel steering gear 40 according to actual needs.

[0036] like Figure 2 As shown, in one embodiment of the present application, the electronically controlled hydraulic unit 30 and the steering wheel steering gear 40 are connected in parallel between the oil source 10 and the steering drive unit 20. The electronically controlled hydraulic unit 30 is used to remotely control the steering of the engineering vehicle, and the steering wheel steering gear 40 corresponds to the steering wheel in the cab to operate the steering of the engineering vehicle. The electronically controlled hydraulic unit 30 and the steering wheel steering gear 40 are connected in parallel in the hydraulic pipeline, and can both be used to independently control the steering of the engineering vehicle.

[0037] In one embodiment of the present application, the steering drive unit 20 is provided with a first oil circuit 23 and a second oil circuit 24, one of which is used to input pressure oil and the other is used to return oil, and the flow direction of the oil in the first oil circuit 23 and the second oil circuit 24 corresponds to the driving direction of the first hydraulic drive element 21 and the second hydraulic drive element 22. Specifically, when the first oil circuit 23 inputs pressure oil and the second oil circuit 24 is used to return oil, the first hydraulic drive element 21 and the second hydraulic drive element 22 perform action 1, and when the first oil circuit 23 is used to return oil and the second oil circuit 24 inputs pressure oil, the first hydraulic drive element 21 and the second hydraulic drive element 22 perform action 2, and action 1 and action 2 are reverse actions.

[0038] Further references Figure 1 The two working oil ports on the output side of the steering solenoid valve 31 are connected to the first oil circuit 23 and the second oil circuit 24 respectively. The steering solenoid valve 31 can control the oil flow direction in the first oil circuit 23 and the second oil circuit 24, thereby controlling the action of the first hydraulic drive element 21 and the second hydraulic drive element 22. The two working oil ports of the steering wheel steering gear 40 are connected to the first oil circuit 23 and the second oil circuit 24 respectively. The steering wheel steering gear 40 can control the oil flow direction in the first oil circuit 23 and the second oil circuit 24, thereby controlling the action of the first hydraulic drive element 21 and the second hydraulic drive element 22.

[0039] Furthermore, the steering solenoid valve 31 is an electromagnetic reversing valve, which is used to switch the oil flow direction in the first oil circuit 23 and the second oil circuit 24. Specifically as shown in Figure 1, the steering solenoid valve 31 includes three working positions. When the valve core is located at the working position on the left, the pressure oil enters the second oil circuit 24, the first oil circuit 23 is used for oil return, and the first hydraulic drive element 21 and the second hydraulic drive element 22 perform action 2; when the valve core is located at the working position on the right, the pressure oil enters the first oil circuit 23, the second oil circuit 24 is used for oil return, and the first hydraulic drive element 21 and the second hydraulic drive element 22 perform action 1; when the valve core is located in the middle position, the steering solenoid valve 31 closes the oil inlet and outlet.

[0040] Furthermore, the electronically controlled hydraulic unit 30 further includes an electronically controlled switching valve 33 and a shuttle valve 34. The two oil inlets of the shuttle valve 34 are respectively connected to the two working oil ports on the output side of the steering solenoid valve 31. The oil source 10 includes an oil source valve 11, and the oil source valve 11 is provided with a control oil port, and the output of the oil source 10 is controlled by the control oil port. The electronically controlled switching valve 33 is respectively connected to the oil outlet of the shuttle valve 34, the pressure feedback oil port of the steering wheel steering gear 40, and the control oil port of the oil source valve 11. The electronically controlled switching valve 33 is a reversing valve and is provided with a first working position and a second working position. When the valve core of the electronically controlled switching valve 33 is switched to the first working position, the control oil port of the control oil source valve 11 is connected to the oil outlet of the shuttle valve 34, and the control oil port of the control oil source valve 11 is not connected to the pressure feedback oil port of the steering wheel steering gear 40. When the valve core of the electronically controlled switching valve 33 is switched to the second working position, the control oil port of the control oil source valve 11 is disconnected from the oil outlet of the shuttle valve 34 , and the control oil port of the control oil source valve 11 is connected to the pressure feedback oil port of the steering wheel steering gear 40 .

[0041] When the steering solenoid valve 31 is used for steering control, one of the two working oil ports on the output side of the steering solenoid valve 31 is used to output pressure oil, and the other is used to return oil. Since the two oil inlets of the shuttle valve 34 are respectively connected to the two working oil ports on the output side of the steering solenoid valve 31, when the steering solenoid valve 31 is used for steering control, the pressure of the oil outlet of the shuttle valve 34 is consistent with the pressure oil, and high-pressure signal oil is output.

[0042] When the valve core of the electric control switching valve 33 is switched to the first working position, the control oil port of the control oil source valve 11 is connected to the oil outlet of the shuttle valve 34, and the control oil port of the control oil source valve 11 is not connected to the pressure feedback oil port of the steering wheel steering gear 40. At this time, the steering solenoid valve 31 can be used for steering control, and the oil outlet of the shuttle valve 34 outputs high-pressure signal oil to the control oil port of the oil source valve 11, so that the oil source 10 can continuously supply pressure oil to drive the steering drive unit 20 to work.

[0043] When the valve core of the electric control switching valve 33 is switched to the second working position, the control oil port of the control oil source valve 11 is not connected to the oil outlet of the shuttle valve 34, and the control oil port of the control oil source valve 11 is connected to the pressure feedback oil port of the steering wheel steering gear 40. At this time, the steering wheel steering gear 40 can be used for steering control, and the pressure feedback oil port of the steering wheel steering gear 40 outputs high-pressure signal oil to the control oil port of the oil source valve 11, so that the oil source 10 can continuously supply pressure oil to drive the steering drive unit 20 to work.

[0044] like Figure 3 As shown, in one embodiment of the present application, the first hydraulic drive element 21 and the second hydraulic drive element 22 are both double-piston rod hydraulic cylinders; wherein, the first hydraulic drive element 21 corresponds to the first double-piston rod hydraulic cylinder, and the second hydraulic drive element 22 corresponds to the second double-piston rod hydraulic cylinder. The first double-piston rod hydraulic cylinder is arranged between the two rear wheels, and the piston rods on both sides thereof respectively drive the steering of the rear wheels on both sides; the second double-piston rod hydraulic cylinder is arranged between the two front wheels, and the piston rods on both sides thereof respectively drive the steering of the front wheels on both sides; the piston rods of the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder can move in the same direction or in the opposite direction to drive the front and rear wheels to rotate in the same direction or in the opposite direction, so that the movement of the engineering vehicle is very flexible and convenient for operation in a narrow space.

[0045] In one embodiment of the present application, the steering drive unit 20 further includes a steering mode switching valve 25, which is disposed between the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder. The steering mode switching valve 25 is an electromagnetic reversing valve, which has at least a first working position and a second working position. When its valve core is located at the first working position, the piston rods of the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder move in the same direction, and when its valve core is located at the second working position, the piston rods of the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder move in opposite directions. Here, by manipulating the steering mode switching valve 25, the working modes of the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder can be controlled. Working mode 1 is that the piston rods of the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder move in the same direction, and working mode 2 is that the piston rods of the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder move in opposite directions.

[0046] Furthermore, the steering mode switching valve 25 also has a third working position. When the valve core is located at the third working position, the first double-piston-rod hydraulic cylinder acts alone, and the second double-piston-rod hydraulic cylinder remains stationary.

[0047] like Figure 1 As shown, a bidirectional hydraulic lock 26 is also provided between the steering mode switching valve 25 and the second double-piston rod hydraulic cylinder. The bidirectional hydraulic lock is composed of two hydraulically controlled one-way valves, and the two hydraulically controlled one-way valves take the pressure of the other oil circuit as the pilot oil. When one pipeline has no pressure, the other pipeline is closed at the same time.

[0048] Furthermore, the remote controller 32 is a wireless controller that can be used to control the actions of all electromagnetic valves. The remote controller 32 can control the steering electromagnetic valve 31, the electric control switching valve 33, and the steering mode switching valve 25, and can remotely control various steering-related operations.

[0049] It should be understood that engineering vehicles can be used for transportation, excavation, emergency repair, etc. Engineering vehicles are usually equipped with various types of working arms for implementing various tasks, and can be used in municipal operations in old cities, mine operations, railway construction, subway construction, etc. Common engineering vehicles include large cranes, excavators, bulldozers, road rollers, loaders, power repair vehicles, and engineering rescue vehicles. All types of engineering vehicles applicable to the technical solution of this application are included in the scope of this application.

[0050] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0052] The specific embodiments described herein are merely examples of the spirit of the present application. A person skilled in the art of the present application may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present application or exceed the scope defined by the attached claims.

Claims

1. A hydraulic steering device for an engineering vehicle, characterized in that: include: An oil source, for providing pressurized oil; A steering drive unit, comprising a first hydraulic drive element and a second hydraulic drive element, wherein the first hydraulic drive element is used to drive the rear wheel steering, and the second hydraulic drive element is used to drive the front wheel steering; The electronically controlled hydraulic unit comprises a steering solenoid valve and a remote controller for controlling the movement of the steering solenoid valve; the steering solenoid valve is arranged between the oil source and the steering drive unit, and is used to control the steering drive unit to achieve steering; The steering wheel steering gear is arranged between the oil source and the steering drive unit, and is used to control the steering drive unit to achieve steering according to the steering operation of the steering wheel.

2. The hydraulic steering device for an engineering vehicle according to claim 1, characterized in that: The electronically controlled hydraulic unit and the steering wheel steering gear are connected in parallel between the oil source and the steering drive unit.

3. The hydraulic steering device for an engineering vehicle according to claim 2, characterized in that: The steering drive unit is provided with a first oil circuit and a second oil circuit, one of which is used to input pressure oil and the other is used to return oil, and the oil flow directions in the first oil circuit and the second oil circuit correspond to the driving directions of the first hydraulic drive element and the second hydraulic drive element; The two working oil ports on the output side of the steering solenoid valve are connected to the first oil circuit and the second oil circuit respectively; the two working oil ports of the steering wheel steering gear are connected to the first oil circuit and the second oil circuit respectively.

4. The hydraulic steering device for an engineering vehicle according to claim 3, characterized in that: The steering solenoid valve is an electromagnetic reversing valve, which is used to switch the flow direction of oil in the first oil circuit and the second oil circuit.

5. The hydraulic steering device for an engineering vehicle according to claim 4, characterized in that: The electronically controlled hydraulic unit also includes an electronically controlled switching valve and a shuttle valve; The two oil inlets of the shuttle valve are respectively connected to the two working oil ports on the output side of the steering solenoid valve; The oil source comprises an oil source valve, and the oil source valve is provided with a control oil port, through which the output of the oil source is controlled; The electronically controlled switching valve is respectively connected to the oil outlet of the shuttle valve, the pressure feedback oil port of the steering wheel gear, and the control oil port of the oil source valve; the electronically controlled switching valve is a reversing valve and is provided with a first working position and a second working position. When the valve core of the electronically controlled switching valve is switched to the first working position, the control oil port of the control oil source valve is connected to the oil outlet of the shuttle valve, and the control oil port of the control oil source valve is not connected to the pressure feedback oil port of the steering wheel gear; when the valve core of the electronically controlled switching valve is switched to the second working position, the control oil port of the control oil source valve is not connected to the oil outlet of the shuttle valve, and the control oil port of the control oil source valve is connected to the pressure feedback oil port of the steering wheel gear.

6. The hydraulic steering device for an engineering vehicle according to any one of claims 1 to 5, characterized in that: The first hydraulic drive element and the second hydraulic drive element are both double-piston-rod hydraulic cylinders; wherein the first hydraulic drive element corresponds to the first double-piston-rod hydraulic cylinder, and the second hydraulic drive element corresponds to the second double-piston-rod hydraulic cylinder; The first double-piston-rod hydraulic cylinder is arranged between the two rear wheels, and the piston rods on both sides thereof respectively drive the steering of the rear wheels on both sides; the second double-piston-rod hydraulic cylinder is arranged between the two front wheels, and the piston rods on both sides thereof respectively drive the steering of the front wheels on both sides; the piston rods of the first double-piston-rod hydraulic cylinder and the second double-piston-rod hydraulic cylinder can move in the same direction or in opposite directions to drive the front wheels and the rear wheels to rotate in the same direction or in opposite directions.

7. The hydraulic steering device for an engineering vehicle according to claim 6, characterized in that: The steering drive unit further includes a steering mode switching valve, which is disposed between the first double-piston rod hydraulic cylinder and the second double-piston rod hydraulic cylinder; The steering mode switching valve is an electromagnetic reversing valve, which has at least a first working position and a second working position. When its valve core is located in the first working position, the piston rods of the first double-piston-rod hydraulic cylinder and the second double-piston-rod hydraulic cylinder move in the same direction. When its valve core is located in the second working position, the piston rods of the first double-piston-rod hydraulic cylinder and the second double-piston-rod hydraulic cylinder move in the opposite direction.

8. The hydraulic steering device for an engineering vehicle according to claim 7, characterized in that: The steering mode switching valve also has a third working position. When the valve core is located at the third working position, the first double-piston-rod hydraulic cylinder acts alone, and the second double-piston-rod hydraulic cylinder remains stationary.

9. The hydraulic steering device for an engineering vehicle according to claim 8, characterized in that: A bidirectional hydraulic lock is also provided between the steering mode switching valve and the second double-piston rod hydraulic cylinder.

10. The hydraulic steering device for an engineering vehicle according to claim 7, characterized in that: The remote controller is a wireless controller and can be used to control the actions of all solenoid valves.

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