Steering system

Abstract

The utility model discloses a steering system. The system comprises a hydraulic oil tank, a steering power mechanism, a steering loop and a steering execution mechanism which are sequentially connected through a pipeline. The steering loop comprises a first steering loop and a second steering loop which are connected in parallel; when the steering power mechanism works normally, the first steering loop provides power for the steering execution mechanism, and the second steering loop executes lifting work of the suspension. When the steering power mechanism fails, the second steering loop provides power for the steering power mechanism; and the steering execution mechanism is connected with the hydraulic oil tank. According to the invention, energy consumption is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of steering, and in particular, to a steering system. Background Art

[0002] Heavy vehicles refer to vehicles with large weight and volume, which are mainly used to transport large quantities of goods or perform special operations. Their steering systems include steering mechanisms and emergency steering mechanisms. When the engine fails, the emergency steering mechanism can be used for steering.

[0003] At present, some steering systems include suspension lifting mechanisms. However, the emergency steering mechanism only works when the engine fails. It does not work during normal driving, but will continue to work, thereby generating more ineffective energy consumption and increasing fuel consumption. Summary of the invention

[0004] The embodiments of the present application provide a steering system that effectively reduces energy consumption.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0006] According to a first aspect of an embodiment of the present application, there is provided a steering system, comprising a hydraulic oil tank, a steering power mechanism, a steering circuit and a steering actuator connected in sequence through pipelines;

[0007] The steering circuit comprises a first steering circuit and a second steering circuit connected in parallel;

[0008] When the steering power mechanism works normally, the first steering circuit provides power to the steering actuator, and the second steering circuit performs suspension lifting and lowering work;

[0009] When the steering power mechanism fails, the second steering circuit provides power to the steering power mechanism;

[0010] The steering actuator is connected to the hydraulic oil tank.

[0011] In some embodiments of the present application, based on the aforementioned scheme, the steering circuit also includes a first three-way reversing valve, the first three-way reversing valve has an oil return port, the oil inlet of the first three-way reversing valve and the steering power mechanism are connected through a pipeline, the first oil outlet and the first steering circuit are connected through a pipeline to provide power to the steering actuator through the first steering circuit, the second oil outlet and the second steering circuit are connected through a pipeline to perform suspension lifting and lowering work through the second steering circuit, and the oil return port and the hydraulic oil tank are connected through a pipeline.

[0012] In some embodiments of the present application, based on the aforementioned scheme, the first steering circuit includes a control valve, the control valve has an oil return port, the oil inlet of the control valve and the first oil outlet of the first three-way reversing valve are connected by a pipeline, the oil outlet is connected to the steering actuator, and the oil return port is connected to the hydraulic oil tank.

[0013] In some embodiments of the present application, based on the aforementioned scheme, the first steering circuit also includes a one-way valve, which is arranged between the oil outlet of the first three-way reversing valve and the steering actuator, and the allowed flow direction of the one-way valve is from the oil outlet of the first three-way reversing valve to the steering actuator.

[0014] In some embodiments of the present application, based on the aforementioned solution, the control valve is a flow control valve.

[0015] In some embodiments of the present application, based on the aforementioned scheme, the second steering circuit includes a first solenoid valve, a second solenoid valve, and a second three-way reversing valve connected in sequence through pipelines, the first solenoid valve and the second oil outlet of the first three-way reversing valve are connected, the pipeline between the first solenoid valve and the second solenoid valve is connected to a suspension lifting actuator, the oil inlet of the second three-way reversing valve is connected to the second solenoid valve, the first oil outlet is connected to the hydraulic oil tank, and the second oil outlet is connected to the steering actuator.

[0016] In some embodiments of the present application, based on the aforementioned solution, the suspension lifting actuator includes an oil-gas spring, and the oil-gas spring is connected to a pipeline between the first solenoid valve and the second solenoid valve.

[0017] In some embodiments of the present application, based on the aforementioned solution, a flow valve is provided between the second oil outlet of the second three-way reversing valve and the steering actuator.

[0018] In some embodiments of the present application, based on the aforementioned solution, the steering power mechanism is a steering pump.

[0019] In some embodiments of the present application, based on the aforementioned scheme, the steering actuator includes a steering gear and a steering cylinder, one end of the oil inlet pipeline of the steering gear is connected to the steering circuit through a pipeline, and the other end is connected to the first oil port of the steering cylinder through a pipeline through a reversing valve, one end of the oil outlet pipeline is connected to the hydraulic oil tank through a pipeline, and the other end is connected to the second oil port of the steering cylinder through a pipeline.

[0020] The beneficial effects of this application are as follows:

[0021] The second steering circuit can perform both suspension lifting and lowering operations and emergency steering operations. Compared with existing steering systems, it reduces the emergency steering mechanism, thereby effectively reducing energy consumption.

[0022] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 A schematic diagram of an existing steering system is shown;

[0025] Figure 2 A schematic diagram of a steering system in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0028] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0029] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0030] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0031] Figure 1 shows a schematic diagram of an existing steering system, Figure 1 1 is a rising valve, 2 is an oil-gas spring, 3 is an oil supply control valve, 4 is a first flow control valve, 5 is a descending valve, 6 is an emergency valve, 7 is a steering pump, 8 is an emergency pump, 9 is a second flow control valve, 10 is a steering gear, 11 is a booster cylinder, and 12 is a hydraulic oil tank. For a better understanding of the embodiments of the present application, see Figure 1 , the existing steering system is described:

[0032] The steering system includes a steering power-assist circuit, an emergency steering circuit and a suspension lifting circuit. The steering power-assist circuit includes a steering pump, an oil supply control valve, a first flow control valve, an emergency valve, a steering gear, a power cylinder and a steering oil tank which are connected in sequence through pipelines. The oil supply control valve is a control valve having an oil inlet, two oil outlets and an oil return port. The first flow control valve is a control valve having an oil inlet, an oil outlet and an oil return port. The emergency valve is a control valve having two oil inlets, an oil outlet and an oil return port. Hydraulic oil is stored in the steering oil tank. One end of the steering pump is connected to the steering oil tank, and the other end is connected to the oil inlet of the oil supply control valve, i.e., port P. The first oil outlet of the oil supply control valve, i.e., port A, is connected to the oil inlet of the first flow control valve, i.e., port P. The oil return port of the oil supply control valve, i.e., port T, is connected to the steering oil tank. The oil outlet of the first flow control valve, i.e., port A, is connected to the first oil inlet of the emergency valve, i.e., port P1. The first flow The oil return port of the control valve, namely the T port, is connected to the steering oil tank, the oil return port of the emergency valve, namely the T port, is connected to the steering oil tank, one end of the oil inlet pipeline of the steering gear is connected to the oil outlet port of the emergency valve, namely the A port, and the other end is connected to the oil inlet of the power cylinder, one end of the oil outlet pipeline is connected to the oil outlet of the power cylinder, and the other end is connected to the steering oil tank, the emergency steering circuit includes an emergency pump, a second flow control valve, an emergency valve and a steering oil tank connected in sequence through pipelines, the oil inlet of the emergency pump is connected to the steering oil tank, the oil outlet is connected to the oil inlet port of the second flow control valve, namely the P port, the oil outlet port of the second flow control valve, namely the A port, is connected to the second oil inlet port of the emergency valve, namely the P2 port, and the oil return port is connected to the steering oil tank, the suspension lifting circuit includes a steering pump, an oil supply control valve, an ascending valve, a descending valve and a steering oil tank connected in sequence through pipelines, and also includes an oil-gas spring, the oil-gas spring is connected to the pipeline between the ascending valve and the descending valve, and the oil supply control valve, the ascending valve and the descending valve are solenoid valves.

[0033] When the vehicle is driving normally, the steering pump draws hydraulic oil from the steering tank to form the first high-pressure oil, which enters the P port of the oil supply control valve. The electromagnet in the oil supply control valve shall not be energized, and the first high-pressure oil flows out from the A port of the oil supply control valve and enters the P port of the first flow control valve. After being throttled by the first flow control valve, the first high-pressure oil enters the P1 port of the emergency valve. At the same time, the emergency pump draws hydraulic oil from the steering tank to form the second high-pressure oil, which enters the P port of the second flow control valve, and then flows out from the A port of the second flow control valve and enters the P2 port of the emergency valve. Since there is hydraulic oil at the P1 port, a pressure difference is generated on both sides of the upper valve core after passing through the throttle valve on the left, overcoming the spring force and pushing the valve core to the left position, so that the first high-pressure oil at the P1 port enters the A port of the emergency valve to provide power for the steering gear, and the second high-pressure oil at the P2 port enters the T port of the emergency valve and flows back to the steering tank.

[0034] When the engine or steering pump fails, the first high-pressure oil is not generated, that is, no hydraulic oil flows through the P1 port of the emergency valve. Under the action of vehicle inertia, the emergency pump draws hydraulic oil from the steering tank to form the second high-pressure oil that enters the P2 port. The valve core is in the right position under the action of the spring, and the second high-pressure oil from the P2 port enters the A port to provide power for the steering gear.

[0035] When the suspension is raised or lowered, the electromagnet in the oil supply control valve is energized, and the high-pressure oil generated by the steering pump flows out from port B of the oil supply control valve and enters the suspension lifting circuit. When the suspension needs to be raised, the rising valve is energized, the descending valve is de-energized, and the hydraulic oil enters the oil-gas spring, and the suspension rises. When the suspension is lowered, the rising valve is de-energized, the descending valve is energized, the oil supply circuit is disconnected, the oil drain circuit is opened, and the hydraulic oil in the oil-gas spring flows back to the steering tank through the descending valve.

[0036] Because the emergency pump is in working state for a long time, it generates more invalid energy consumption and increases fuel consumption.

[0037] Figure 2 A schematic diagram of a steering system in an embodiment of the present application is shown. Figure 2 2 is a gas spring, 7 is a steering pump, 10 is a steering gear, 11 is a power cylinder, i.e., a steering oil cylinder, 12 is a steering oil tank, i.e., a hydraulic oil tank, 13 is a first three-way reversing valve, 14 is a control valve, 15 is a check valve, 16 is a flow valve, 17 is a second three-way reversing valve, 18 is a second solenoid valve, 19 is a first solenoid valve, see Figure 2 , provides a steering system, which at least includes a hydraulic oil tank, a steering power mechanism, a steering circuit and a steering actuator connected in sequence through pipelines, which are described in detail as follows:

[0038] The steering circuit includes a first steering circuit and a second steering circuit connected in parallel, and the first steering circuit and the second steering circuit are used to transmit the power generated by the steering power mechanism, such as transmitting high-pressure oil;

[0039] When the steering power mechanism is working normally, that is, when the vehicle is driving normally, the first steering circuit provides power to the steering actuator, and the second steering circuit performs suspension lifting and lowering work;

[0040] When the steering power mechanism fails, the second steering circuit provides power to the steering power mechanism;

[0041] The steering actuator is connected to the hydraulic oil tank.

[0042] Optionally, the steering circuit also includes a first three-way reversing valve, which has an oil return port, the oil inlet of the first three-way reversing valve and the steering power mechanism are connected through a pipeline, the first oil outlet and the first steering circuit are connected through a pipeline to provide power to the steering actuator through the first steering circuit, the second oil outlet and the second steering circuit are connected through a pipeline to perform suspension lifting and lowering work through the second steering circuit, and the oil return port and the hydraulic oil tank are connected through a pipeline.

[0043] Specifically, when switching through the first three-way reversing valve, it can be achieved by the hydraulic oil flowing out from different oil outlets. The hydraulic oil enters the first steering circuit through the oil inlet and the first oil outlet, and enters the second steering circuit through the oil inlet and the second oil outlet.

[0044] Optionally, the first steering circuit includes a control valve having an oil return port, the oil inlet of the control valve and the first oil outlet of the first three-way reversing valve are connected by a pipeline, the oil outlet is connected to the steering actuator, and the oil return port is connected to the hydraulic oil tank.

[0045] Optionally, the first steering circuit further comprises a one-way valve, which is arranged between the oil outlet of the first three-way reversing valve and the steering actuator, and the allowed flow direction of the one-way valve is from the oil outlet of the first three-way reversing valve to the steering actuator.

[0046] Optionally, the control valve is a flow control valve.

[0047] Optionally, the second steering circuit includes a first solenoid valve, a second solenoid valve and a second three-way reversing valve which are connected in sequence through pipelines, the first solenoid valve and the second oil outlet of the first three-way reversing valve are connected, the pipeline between the first solenoid valve and the second solenoid valve is connected to a suspension lifting actuator, the oil inlet of the second three-way reversing valve is connected to the second solenoid valve, the first oil outlet is connected to the hydraulic oil tank, and the second oil outlet is connected to the steering actuator.

[0048] Optionally, the suspension lifting actuator includes an oil-gas spring, and the oil-gas spring is connected to a pipeline between the first solenoid valve and the second solenoid valve.

[0049] Optionally, a flow valve is provided between the second oil outlet of the second three-way reversing valve and the steering actuator.

[0050] Optionally, the steering power mechanism is a steering pump.

[0051] Optionally, the steering actuator includes a steering gear and a steering cylinder, one end of the steering gear's oil inlet pipeline is connected to the steering circuit through a pipeline, and the other end is connected to the first oil port of the steering cylinder through a pipeline via a reversing valve, one end of the oil outlet pipeline is connected to the hydraulic oil tank through a pipeline, and the other end is connected to the second oil port of the steering cylinder through a pipeline via a reversing valve, the reversing valve is connected to the steering wheel, and when the steering wheel is in the middle position, the oil inlet pipeline is connected to the oil outlet pipeline through the reversing valve, and the hydraulic oil is discharged from the oil inlet pipeline. The pipeline passes through the oil outlet pipeline and flows back to the hydraulic oil tank, so no steering is performed. When the steering wheel turns to the left, the oil inlet pipeline enters the first oil port through the reversing valve, and the oil outlet pipeline enters the second oil port. At this time, the first oil port is the oil inlet and the second oil port is the oil outlet, and the steering cylinder drives the wheel to turn left. When the steering wheel turns to the right, the oil inlet pipeline enters the second oil port through the reversing valve, and the oil outlet pipeline enters the first oil port. At this time, the second oil port is the oil inlet and the first oil port is the oil outlet, and the steering cylinder drives the wheel to turn right.

[0052] Optionally, when the steering power mechanism works normally, the first steering circuit provides power to the steering actuator, and the second steering circuit performs suspension lifting work, including:

[0053] The steering power mechanism draws hydraulic oil from the hydraulic oil tank to form high-pressure oil, which enters the first three-way reversing valve. When the high-pressure oil flows out from the first oil outlet, the first steering circuit provides power to the steering actuator to enable the steering actuator to perform steering work. When the high-pressure oil flows out from the second oil outlet, the second steering circuit performs suspension lifting work.

[0054] For a better understanding of the embodiments of the present application, see Figure 2 , provides a specific example as follows:

[0055] A steering system comprises a hydraulic oil tank, a steering pump, a steering circuit and a steering actuator connected in sequence through pipelines, wherein the steering circuit comprises a first steering circuit and a second steering circuit connected in parallel, and further comprises a first three-way reversing valve, wherein the first three-way reversing valve has an oil return port, namely a T port, the steering pump is connected to an oil inlet, namely a P port, the first oil outlet, namely a port A, is connected to the first steering circuit through a pipeline to provide power to the steering actuator through the first steering circuit, and the second oil outlet, namely a port B, is connected to the second steering circuit through a pipeline to pass the oil return port. The suspension lifting work is performed through the second steering circuit, the oil return port, namely the T port, is connected to the hydraulic oil tank through a pipeline, the first steering circuit includes a control valve and a one-way valve, the control valve has an oil return port, namely the T port, the oil inlet, namely the P port, of the control valve and the first oil outlet, namely the A port, of the first three-way reversing valve are connected by a pipeline, the oil outlet, namely the A port, is connected to the one-way valve, the one-way valve is connected to the steering actuator, the allowable flow direction of the one-way valve is from the oil outlet of the first three-way reversing valve to the steering actuator, the oil return port, namely the T port, of the first three-way reversing valve is connected to the hydraulic oil tank The second steering circuit includes a first solenoid valve, a second solenoid valve and a second three-way reversing valve which are sequentially connected through pipelines. The first solenoid valve is connected to a second oil outlet, i.e., port B, of the first three-way reversing valve. The pipeline between the first solenoid valve and the second solenoid valve is connected to a suspension lifting actuator. The oil inlet of the second three-way reversing valve is connected to the second solenoid valve. The first oil outlet is connected to a hydraulic oil tank, and the second oil outlet is connected to a steering actuator. The suspension lifting actuator includes an oil-gas spring, and the oil-gas spring is connected to the first solenoid valve and the second solenoid valve. The pipeline between them is connected, a flow valve is provided between the second oil outlet of the second three-way reversing valve and the steering actuator, the steering actuator includes a steering gear and a steering cylinder, one end of the oil inlet pipeline of the steering gear is connected to the steering circuit through a pipeline, that is, a one-way valve and a flow valve are connected in parallel, and the other end is connected to the first oil port of the steering cylinder through a pipeline through the reversing valve, one end of the oil outlet pipeline is connected to the hydraulic oil tank through a pipeline, and the other end is connected to the second oil port of the steering cylinder through a pipeline through the reversing valve, wherein the first three-way reversing valve and the second three-way reversing valve are solenoid valves.

[0056] When the car is running normally, there is hydraulic oil in the oil-gas spring. The transfer pump draws hydraulic oil from the hydraulic oil tank to form high-pressure oil, which enters the oil inlet of the first three-way reversing valve. The oil outlet of the first three-way reversing valve is port A. The high-pressure oil enters port P of the control valve from port A, and then enters the one-way valve from port A of the control valve, and enters the steering gear from the one-way valve to perform steering work. When the steering pump fails, the first solenoid valve disconnects the pipeline, and the second solenoid valve connects the pipeline. The oil outlet of the second three-way reversing valve is the second oil outlet, and the hydraulic oil in the oil-gas spring passes through the second solenoid valve, the second three-way reversing valve and the flow valve and enters the steering gear to enable the steering gear to perform steering work.

[0057] When the suspension is lifted or lowered, the oil outlet of the first three-way reversing valve is port B. When the suspension needs to rise, the first solenoid valve connects the pipeline, the second solenoid valve disconnects the pipeline, the oil outlet of the second three-way reversing valve is the first oil outlet, and high-pressure oil enters the oil-gas spring. The suspension rises. When the suspension needs to be lowered, the first solenoid valve disconnects the pipeline, the second solenoid valve connects the pipeline, the oil outlet of the second three-way reversing valve is the first oil outlet, the oil supply line is disconnected, the oil drain line is opened, and the high-pressure oil in the oil-gas spring flows back to the hydraulic oil tank through the second solenoid valve and the second three-way reversing valve.

[0058] It should be understood that, for the first solenoid valve and the second solenoid valve, the connection and disconnection of the pipeline can be achieved by energizing and de-energizing. For example, for the first solenoid valve, the pipeline is connected when energized and disconnected when de-energized. It can also be that the pipeline is disconnected when energized and connected when de-energized. For the first three-way reversing valve and the second three-way reversing valve, the switching can be achieved by energizing and de-energizing. For example, for the first three-way reversing valve, it switches to the first oil outlet when energized and switches to the second oil outlet when de-energized. It can also be that it switches to the second oil outlet when energized and switches to the first oil outlet when de-energized.

[0059] In the present application, the second steering circuit can perform both suspension lifting and lowering operations and emergency steering operations. Compared with the existing steering system, the emergency steering mechanism is reduced, thereby effectively reducing energy consumption.

[0060] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0061] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0062] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0063] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly or all or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc., which can store program code.

[0064] The above description is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A steering system, characterized in that: It includes a hydraulic oil tank, a steering power mechanism, a steering circuit and a steering actuator which are sequentially connected through pipelines; The steering circuit comprises a first steering circuit and a second steering circuit connected in parallel; When the steering power mechanism works normally, the first steering circuit provides power to the steering actuator, and the second steering circuit performs suspension lifting and lowering work; When the steering power mechanism fails, the second steering circuit provides power to the steering actuator; The steering actuator is connected to the hydraulic oil tank.

2. A steering system according to claim 1, characterized in that: The steering circuit also includes a first three-way reversing valve, which has an oil return port. The oil inlet of the first three-way reversing valve is connected to the steering power mechanism through a pipeline, the first oil outlet is connected to the first steering circuit through a pipeline to provide power to the steering actuator through the first steering circuit, the second oil outlet is connected to the second steering circuit through a pipeline to perform suspension lifting and lowering work through the second steering circuit, and the oil return port is connected to the hydraulic oil tank through a pipeline.

3. A steering system according to claim 2, characterized in that: The first steering circuit includes a control valve having an oil return port, an oil inlet of the control valve and a first oil outlet of the first three-way reversing valve are connected by a pipeline, the oil outlet is connected to a steering actuator, and the oil return port is connected to a hydraulic oil tank.

4. A steering system according to claim 3, characterized in that: The first steering circuit also includes a one-way valve, which is arranged between the oil outlet of the first three-way reversing valve and the steering actuator, and the allowed flow direction of the one-way valve is from the oil outlet of the first three-way reversing valve to the steering actuator.

5. A steering system according to claim 3, characterized in that: The control valve is a flow control valve.

6. A steering system according to claim 2, characterized in that: The second steering circuit includes a first solenoid valve, a second solenoid valve and a second three-way reversing valve which are connected in sequence through pipelines, the first solenoid valve and the second oil outlet of the first three-way reversing valve are connected, the pipeline between the first solenoid valve and the second solenoid valve is connected to a suspension lifting actuator, the oil inlet of the second three-way reversing valve is connected to the second solenoid valve, the first oil outlet is connected to the hydraulic oil tank, and the second oil outlet is connected to the steering actuator.

7. A steering system according to claim 6, characterized in that: The suspension lifting actuator comprises an oil-gas spring, and the oil-gas spring is connected to a pipeline between the first solenoid valve and the second solenoid valve.

8. A steering system according to claim 6, characterized in that: A flow valve is provided between the second oil outlet of the second three-way reversing valve and the steering actuator.

9. A steering system according to claim 1, characterized in that: The steering power mechanism is a steering pump.

10. A steering system according to claim 1, characterized in that: The steering actuator includes a steering gear and a steering cylinder. One end of the steering gear's oil inlet pipeline is connected to the steering circuit through a pipeline, and the other end is connected to the first oil port of the steering cylinder through a pipeline via a reversing valve. One end of the oil outlet pipeline is connected to the hydraulic oil tank through a pipeline, and the other end is connected to the second oil port of the steering cylinder through a pipeline via a reversing valve.

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