Electro-hydraulic proportional navigation control system capable of realizing full-automatic navigation and tractor

Abstract

The utility model relates to an electro-hydraulic proportional navigation control system capable of realizing full-automatic navigation and a tractor. The electro-hydraulic proportional navigation control system comprises a pump, a first oil way, a second oil way, a first branch, a second branch, a steering gear, a first control valve, a steering electronic control hydraulic module and a double-acting steering oil cylinder, an oil outlet of the pump is connected with the first oil way and the second oil way, the first oil way is connected with the first branch and the second branch through the first control valve, and the second oil way is connected with the second branch through the second control valve. The first branch and the second branch are connected with an oil inlet of the steering gear, an oil return opening of the steering gear is connected with an oil return pipeline, a second control valve is arranged on the second branch, and the second oil way is connected with connectors of two oil cavities of the double-acting steering oil cylinder through a steering electric control hydraulic module. And two steering oil ports of the steering gear are respectively connected with interfaces of two oil cavities of the double-acting steering oil cylinder. The system has the advantages that an automatic mode and a manual mode can be flexibly switched, the control is accurate, the response is fast, the overall integration degree is high, and the occupied space is small.

Description

Technical Field

[0001] The utility model relates to the technical field of navigation control systems, in particular to an electro-hydraulic proportional navigation control system and a tractor capable of realizing full-automatic navigation. Background Art

[0002] In recent years, the application of automated navigation technology for agricultural machinery has continued to expand in my country. This technology improves the accuracy of agricultural machinery's straight-line travel and operations, reduces overlap and alignment errors, and reduces driver fatigue. Domestic and international application results demonstrate that automated steering is a key technology in automated navigation for agricultural machinery.

[0003] At present, most agricultural machinery automatic steering technologies use electronic steering wheels. Their installation and use will occupy the original space in the cab, which will invisibly reduce the driver's driving experience.

[0004] Based on this, it is necessary to develop an electro-hydraulic proportional navigation control system and a tractor that can realize fully automatic navigation to overcome the above technical problems. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide an electro-hydraulic proportional navigation control system and a tractor capable of realizing full-automatic navigation, which effectively overcomes the defects of the prior art.

[0006] The technical solution of the utility model to solve the above technical problems is as follows:

[0007] An electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation comprises a pump, a first oil circuit, a second oil circuit, a first branch, a second branch, a steering gear, a first control valve, a steering electronically controlled hydraulic module and a double-acting steering cylinder, wherein the oil outlet of the pump is respectively connected to the first oil circuit and the second oil circuit, the first oil circuit is respectively connected to the first branch and the second branch through the first control valve, the first branch and the second branch are respectively connected to the oil inlet of the steering gear, the oil return port of the steering gear is connected to the oil return pipeline, a second control valve is provided on the second branch, the second oil circuit is respectively connected to the interfaces of the two oil chambers of the double-acting steering cylinder through the steering electronically controlled hydraulic module, and the two steering oil ports of the steering gear are respectively connected to the interfaces of the two oil chambers of the double-acting steering cylinder.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the above-mentioned first control valve is a two-position three-way solenoid valve, which has an oil inlet and two working oil ports. The above-mentioned first oil circuit is connected to the oil inlet of the above-mentioned first control valve, and the two working oil ports of the above-mentioned first control valve are respectively connected to the above-mentioned first branch and the second branch. When the above-mentioned two-position three-way solenoid valve is energized or de-energized, the valve core moves, so that one of the oil inlets is connected to the two above-mentioned working oil ports.

[0010] Furthermore, the above-mentioned second control valve is a two-position two-way hydraulic valve, the inlet and working oil port of which are connected in series to the above-mentioned second branch, the non-spring side chamber of the above-mentioned second control valve is connected to the upstream of the above-mentioned second branch through a pipeline, and the spring side chamber of the above-mentioned second control valve is connected to the above-mentioned steering electronic hydraulic module through a pipeline.

[0011] Furthermore, the steering electronically controlled hydraulic module includes two steering control solenoid valves, a third control valve, a fourth control valve and a fifth control valve. The fourth control valve has an oil inlet, an oil return port, a first interface, a second interface and a third interface. The fourth control valve has a movable valve core, and spring side cavities are formed at both ends of the valve core. The second oil circuit is connected to the oil inlet and the two spring side cavities of the fourth control valve through pipelines. The two steering control solenoid valves are respectively and correspondingly arranged on the pipeline connecting the second oil circuit and the two spring side cavities of the fourth control valve. The third control valve is arranged on the pipeline connecting the second oil circuit and the fourth control valve. The first interface and the third interface are respectively connected to the fifth control valve. The fifth control valve is respectively connected to the double-acting The interfaces of the two oil chambers of the steering cylinder, the above-mentioned second interface is connected to the spring side chamber of the above-mentioned second control valve through a pipeline. When the two above-mentioned steering control solenoid valves are energized or de-energized, the valve core moves, so that the pipelines where they are located are unobstructed and disconnected, thereby pushing the valve core of the above-mentioned fourth control valve to move from the middle position to either end, or to remain in the middle position, and when the valve core of the above-mentioned fourth control valve is in the middle position, the return oil port of the above-mentioned fourth control valve is connected to the second interface, when the valve core of the above-mentioned fourth control valve moves to both ends, the oil inlet of the above-mentioned fourth control valve is connected to the first interface or the third interface, and the oil return port of the above-mentioned fourth control valve is connected to the third interface or the first interface, at the same time, the first interface or the third interface of the above-mentioned fourth control valve is connected to the second interface, and the oil return port of the above-mentioned fourth control valve is connected to the oil return pipeline.

[0012] Furthermore, the above-mentioned steering control solenoid valve is a two-position three-way solenoid valve, which has an oil inlet, an oil return port and a working oil port. The oil inlet of the above-mentioned steering control solenoid valve is connected to the above-mentioned second oil circuit through a pipeline, and the two working oil ports of the above-mentioned steering control solenoid valves are respectively connected to the two spring side chambers of the above-mentioned fourth control valve through pipelines. When the above-mentioned steering control solenoid valve is energized or de-energized, the valve core moves so that its working oil port is selectively connected to the oil inlet or the oil return port, and the oil return port of the above-mentioned steering control solenoid valve is connected to the above-mentioned return oil pipeline.

[0013] Furthermore, the above-mentioned third control valve is a two-position, two-way solenoid valve, which has an oil inlet and an oil outlet. The oil inlet and oil outlet of the above-mentioned third control valve are connected in series on the pipeline connecting the above-mentioned second oil circuit and the above-mentioned fourth control valve. When the above-mentioned third control valve is energized or de-energized, the valve core moves, so that its oil inlet and oil outlet are connected or disconnected.

[0014] Furthermore, the above-mentioned fifth control valve is a two-position four-way solenoid valve, which has an oil inlet, an oil return port and two working oil ports. The oil inlet and oil return port of the above-mentioned fifth control valve are respectively connected to the above-mentioned first interface and the third interface in a one-to-one correspondence. The two working oil ports of the above-mentioned fifth control valve are respectively connected to the interfaces of the two oil chambers of the above-mentioned double-acting steering cylinder through pipelines. When the above-mentioned fifth control valve is energized or de-energized, the valve core moves, so that its oil inlet and oil return port are respectively connected to or disconnected with the two above-mentioned working oil ports in a one-to-one correspondence.

[0015] Furthermore, filters are respectively provided upstream of the pipelines connecting the second oil circuit and the two spring side chambers of the fourth control valve.

[0016] Furthermore, throttle valves are respectively provided downstream of the pipelines connecting the second oil circuit and the two spring side chambers of the fourth control valve.

[0017] The beneficial effects of the utility model are: reasonable structural design, flexible switching between automatic and manual modes, precise control, fast response, high overall integration, and small space occupation.

[0018] A tractor comprising an electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of the electro-hydraulic proportional navigation control system of the utility model which can realize fully automatic navigation.

[0020] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0021] 1. Pump; 2. Steering gear; 3. First control valve; 4. Double-acting steering cylinder; 5. Second control valve; 61. Steering control solenoid valve; 62. Third control valve; 63. Fourth control valve; 64. Fifth control valve. DETAILED DESCRIPTION

[0022] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] Example 1

[0024] like Figure 1 As shown, the electro-hydraulic proportional navigation control system capable of realizing fully automatic navigation of this embodiment includes a pump 1, a first oil circuit, a second oil circuit, a first branch, a second branch, a steering gear 2, a first control valve 3, a steering electronically controlled hydraulic module and a double-acting steering cylinder 4. The oil outlet of the above-mentioned pump 1 is respectively connected to the above-mentioned first oil circuit and the second oil circuit, the above-mentioned first oil circuit is respectively connected to the first branch and the second branch through the above-mentioned first control valve 3, the above-mentioned first branch and the second branch are respectively connected to the oil inlet of the above-mentioned steering gear 2, the oil return port of the above-mentioned steering gear 2 is connected to the oil return pipeline, a second control valve 5 is provided on the above-mentioned second branch, the above-mentioned second oil circuit is respectively connected to the interfaces of the two oil chambers of the above-mentioned double-acting steering cylinder 4 through the steering electronically controlled hydraulic module, and the two steering oil ports of the above-mentioned steering gear 2 are respectively connected to the interfaces of the two oil chambers of the above-mentioned double-acting steering cylinder 4.

[0025] The electro-hydraulic proportional navigation control system of this embodiment, which can realize fully automatic navigation, can be switched between manual mode and automatic mode as needed during use, as follows:

[0026] 1) Manual mode:

[0027] The steering electronic control hydraulic module stops running, the second oil circuit is disconnected, and the first control valve 3 is operated to switch so that the first oil circuit is connected to the first branch. The oil circuit route is: pump 1--first oil circuit--first control valve 3--first branch--steering gear 2. The steering gear 2 is operated to turn left or right, and one of the two steering oil ports of the steering gear 2 is selected to transport oil to the oil chamber interface corresponding to the double-acting steering cylinder 4, thereby making the double-acting steering cylinder 4 operate and drive the vehicle to steer.

[0028] 2) Automatic mode:

[0029] The first control valve 3 is operated to switch so that the first oil circuit and the second branch are connected. A part of the oil output from the pump body 1 is distributed through the steering electronic hydraulic module and enters one of the two oil chambers of the double-acting steering cylinder 4, thereby causing the double-acting steering cylinder 4 to operate and drive the vehicle to steer. At the same time, the second control valve 5 controls the second branch to be disconnected.

[0030] It should be noted that when the steering gear 2 is not in steering operation, its oil inlet and oil return port are in a connected state.

[0031] In this embodiment, the above-mentioned first control valve 3 is a two-position three-way solenoid valve, which has an oil inlet and two working oil ports. The above-mentioned first oil circuit is connected to the oil inlet of the above-mentioned first control valve 3, and the two working oil ports of the above-mentioned first control valve 3 are respectively connected to the above-mentioned first branch and the second branch. When the above-mentioned two-position three-way solenoid valve is energized or de-energized, the valve core moves, so that one of the oil inlets is connected to the two above-mentioned working oil ports.

[0032] As a preferred embodiment, the above-mentioned second control valve 5 is a two-position two-way hydraulic valve, the inlet and the working oil port of the two-position two-way hydraulic valve are connected in series to the above-mentioned second branch, the non-spring side chamber of the above-mentioned second control valve 5 is connected to the upstream of the above-mentioned second branch through a pipeline, and the spring side chamber of the above-mentioned second control valve 5 is connected to the above-mentioned steering electronic hydraulic module through a pipeline.

[0033] In the above implementation scheme, in manual mode, the second branch is disconnected, and the oil directly enters the steering gear 2 through the first branch, and the response speed is very fast; in automatic mode, before steering, the oil will enter the first oil circuit, and enter the non-spring side cavity of the second control valve 5, pushing the valve core to move, so that the first oil circuit and the second branch are unobstructed, and the oil enters the steering gear 2. When the steering gear 2 is not operated, the oil will flow back to the oil tank through the return oil port of the steering gear 2, that is, in automatic mode, there is always pressurized oil entering the steering gear 2, whether it is subsequent manual steering or automatic steering, it can respond quickly, especially when switching to manual steering, since there is always oil entering the steering gear 2, the steering response is very fast.

[0034] As a preferred embodiment, the steering electronically controlled hydraulic module includes two steering control solenoid valves 61, a third control valve 62, a fourth control valve 63 and a fifth control valve 64. The fourth control valve 63 has an oil inlet, an oil return port, a first interface, a second interface and a third interface. The fourth control valve 63 has a movable valve core, and spring side chambers are formed at both ends of the valve core. The second oil circuit is connected to the oil inlet and the two spring side chambers of the fourth control valve 63 through pipelines. The two steering control solenoid valves 61 are respectively and one-to-one arranged on the pipeline connecting the second oil circuit and the two spring side chambers of the fourth control valve 63. The third control valve 62 is arranged on the pipeline connecting the second oil circuit and the fourth control valve 63. The first interface and the third interface are respectively connected to the fifth control valve 64. The fifth control valve 64 is respectively connected to the oil inlet and the two spring side chambers of the fourth control valve 63 through pipelines. The interface connecting the two oil chambers of the above-mentioned double-acting steering cylinder 4, the above-mentioned second interface is connected to the spring side chamber of the above-mentioned second control valve 5 through a pipeline, and the two above-mentioned steering control solenoid valves 61 are energized or de-energized, and the valve core moves, so that the pipelines where they are located are unobstructed and disconnected, thereby pushing the valve core of the above-mentioned fourth control valve 63 to move from the middle position to either end, or to remain in the middle position, and when the valve core of the above-mentioned fourth control valve 63 is in the middle position, the return oil port of the above-mentioned fourth control valve 63 is connected to the second interface, when the valve core of the above-mentioned fourth control valve 63 moves to both ends, the oil inlet of the above-mentioned fourth control valve 63 is selectively connected to the first interface or the third interface, and the oil return port of the above-mentioned fourth control valve 63 is selectively connected to the third interface or the first interface, at the same time, the first interface or the third interface of the above-mentioned fourth control valve 63 is connected to the second interface, and the oil return port of the above-mentioned fourth control valve 63 is connected to the oil return pipeline.

[0035] In the above embodiment, in manual mode, the third control valve 62 disconnects the connection of the pipeline in which it is located; after switching to automatic mode, the third control valve 62 opens, and the oil flows to the two steering control solenoid valves 61 and the fourth control valve 63 respectively through the first oil circuit. When steering in automatic mode, the fifth control valve 64 opens, and one of the two steering control solenoid valves 61 is operated. The oil flowing to the steering control solenoid valve 61 enters the spring side cavity at the corresponding end of the fourth control valve 63, pushing the valve core to move, thereby opening the fourth control valve 63, so that the oil inlet of the above-mentioned fourth control valve 63 is selectively connected to the first interface or the third interface. , and the oil return port of the fourth control valve 63 is selectively connected to the third interface or the first interface. At the same time, the first interface or the third interface of the fourth control valve 63 is connected to the second interface. Oil flows through the oil inlet of the fourth control valve 63 to the first interface or the third interface, and then flows through the first interface or the third interface to the oil chamber corresponding to the double-acting steering cylinder 4, thereby causing the double-acting steering cylinder 4 to operate and drive the vehicle to steer (wherein, when oil enters one oil chamber of the double-acting steering cylinder 4, the oil in the other right chamber will flow outward and return to the fuel tank through the fifth control valve 64 and the fourth control valve 63). At the same time, a portion of the oil flowing to the double-acting steering cylinder 4 through the fourth control valve 63 will flow through the second interface to the spring side chamber of the second control valve 5, thereby causing the valve core of the second control valve 5 to move and disconnect the second branch. When steering is not required, the valve core of the fourth control valve 63 is in the middle position, and the valve core of the second control valve 5 moves in the opposite direction under the action of the spring force, and the second branch remains unobstructed. The oil in the spring side chamber of the second control valve 5 flows back to the oil tank through the second interface and the return oil port of the fourth control valve 63.

[0036] It should be noted that: taking the left, middle and right movements of the valve core of the fourth control valve 63 as an example, the left end of the valve core has a first and a second path distributed vertically in parallel, the middle has a return oil path, and the right end has a third and a fourth path distributed crosswise. After the valve core moves to the left, the right position is connected, the third path connects the oil inlet of the fourth control valve 63 and the first interface, the fourth path connects the oil return port of the fourth control valve 63 and the third interface, and the third path has a bypass branch connected to the second interface. When the valve core of the fourth control valve 63 is in the middle position, the return oil path connects the second interface and the oil return port of the fourth control valve 63. After the valve core of the fourth control valve 63 moves to the right, the left position is connected, that is, the first path connects the oil inlet of the fourth control valve 63 and the third interface, the second path connects the first interface and the oil return port of the fourth control valve 63, and the first path has a bypass branch connected to the second interface.

[0037] In this embodiment, the steering control solenoid valve 61 is a two-position, three-way solenoid valve having an oil inlet, an oil return port, and a working oil port. The oil inlet of the steering control solenoid valve 61 is connected to the second oil circuit via a pipeline, and the two working oil ports of the steering control solenoid valve 61 are connected to the two spring-side chambers of the fourth control valve 63 via pipelines. When the steering control solenoid valve 61 is energized or de-energized, the valve core moves, causing its working oil port to selectively connect to either the oil inlet or the oil return port. The oil return port of the steering control solenoid valve 61 is connected to the oil return pipeline. During steering, the oil inlet and working oil ports of the steering control solenoid valve 61 are connected. During non-steering, the oil return port and working oil port of the steering control solenoid valve 61 are connected.

[0038] In this embodiment, the third control valve 62 is a two-position, two-way solenoid valve having an oil inlet and an oil outlet. These inlet and outlet are connected in series to the pipeline connecting the second oil circuit and the fourth control valve 63. When the third control valve 62 is energized or de-energized, the valve core moves, connecting or disconnecting the inlet and outlet. When the system is in automatic mode, the valve core moves, connecting the inlet and outlet of the third control valve 62 to ensure normal oil supply to the second oil circuit. In manual mode, the valve core moves, disconnecting the inlet and outlet of the third control valve 62.

[0039] In this embodiment, the fifth control valve 64 is a two-position, four-way solenoid valve having an oil inlet, an oil return port, and two working oil ports. The oil inlet and oil return port of the fifth control valve 64 are connected to the first and third ports, respectively, in a one-to-one correspondence. The two working oil ports of the fifth control valve 64 are connected to the ports of the two oil chambers of the double-acting steering cylinder 4 via pipelines. When the fifth control valve 64 is energized or de-energized, the valve core moves, causing its oil inlet and oil return port to connect or disconnect with the two working oil ports, respectively. The valve core of the fifth control valve 64 has two parallel flow channels. When the valve core moves to open, one flow channel connects to the oil inlet and one working oil port, respectively, while the other flow channel connects to both the oil inlet and one working oil port. When closed, the oil inlet and oil return port are disconnected from the two working oil ports.

[0040] In this embodiment, filters are respectively provided upstream of the pipelines connecting the second oil circuit and the two spring side chambers of the fourth control valve 63 .

[0041] In this embodiment, throttle valves are respectively provided downstream of the pipelines connecting the second oil circuit and the two spring side chambers of the fourth control valve 63 .

[0042] Example 2

[0043] The tractor of this embodiment includes the electro-hydraulic proportional navigation control system of embodiment 1 that can realize fully automatic navigation.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 understood as a limitation to the present invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0046] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0047] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0049] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation, characterized by: The invention comprises a pump (1), a first oil circuit, a second oil circuit, a first branch circuit, a second branch circuit, a steering gear (2), a first control valve (3), a steering electronically controlled hydraulic module and a double-acting steering oil cylinder (4), wherein the oil outlet of the pump (1) is respectively connected to the first oil circuit and the second oil circuit, the first oil circuit is respectively connected to the first branch circuit and the second branch circuit via the first control valve (3), the first branch circuit and the second branch circuit are respectively connected to the oil inlet of the steering gear (2), the oil return port of the steering gear (2) is connected to the oil return pipeline, a second control valve (5) is provided on the second branch circuit, the second oil circuit is respectively connected to the interfaces of the two oil chambers of the double-acting steering oil cylinder (4) via the steering electronically controlled hydraulic module, and the two steering oil ports of the steering gear (2) are respectively connected to the interfaces of the two oil chambers of the double-acting steering oil cylinder (4).

2. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 1, characterized in that: The first control valve (3) is a two-position three-way solenoid valve having an oil inlet and two working oil ports. The first oil circuit is connected to the oil inlet of the first control valve (3), and the two working oil ports of the first control valve (3) are respectively connected to the first branch and the second branch. When the two-position three-way solenoid valve is energized or de-energized, the valve core moves so that one of the oil inlets is connected to the two working oil ports.

3. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 1, characterized in that: The second control valve (5) is a two-position, two-way hydraulic valve, the inlet and the working oil port of which are connected in series to the second branch, the non-spring side chamber of the second control valve (5) is connected to the upstream of the second branch via a pipeline, and the spring side chamber of the second control valve (5) is connected to the steering electronic control hydraulic module via a pipeline.

4. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 3, characterized in that: The steering electronic control hydraulic module includes two steering control solenoid valves (61), a third control valve (62), a fourth control valve (63) and a fifth control valve (64). The fourth control valve (63) has an oil inlet, an oil return port, a first interface, a second interface and a third interface. A movable valve core is provided in the fourth control valve (63), and spring side cavities are formed at both ends of the valve core. The second oil circuit is connected to the oil inlet and the two spring side cavities of the fourth control valve (63) through pipelines. The two steering control solenoid valves (61) are respectively arranged on the pipeline connecting the second oil circuit and the two spring side cavities of the fourth control valve (63). The third control valve (62) is arranged on the pipeline connecting the second oil circuit and the fourth control valve (63). The first interface and the third interface are respectively connected to the fifth control valve (64). The fifth control valve (64) is respectively connected to the The interfaces of the two oil chambers of the double-acting steering oil cylinder (4), the second interface is connected to the spring side chamber of the second control valve (5) through a pipeline, the two steering control solenoid valves (61) are energized or de-energized, the valve core moves, so that the pipelines where they are located are disconnected, thereby pushing the valve core of the fourth control valve (63) to move from one of the middle position to the two ends, or to remain in the middle position, and when the valve core of the fourth control valve (63) is in the middle position, the return oil port of the fourth control valve (63) is connected to the second interface, when the valve core of the fourth control valve (63) moves to the two ends, the oil inlet of the fourth control valve (63) is connected to the first interface or the third interface, and the return oil port of the fourth control valve (63) is connected to the third interface or the first interface, at the same time, the first interface or the third interface of the fourth control valve (63) is connected to the second interface, and the return oil port of the fourth control valve (63) is connected to the return oil pipeline.

5. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 4, characterized in that: The steering control solenoid valve (61) is a two-position three-way solenoid valve having an oil inlet, an oil return port and a working oil port. The oil inlet of the steering control solenoid valve (61) is connected to the second oil circuit via a pipeline, and the working oil ports of the two steering control solenoid valves (61) are respectively connected to the two spring side chambers of the fourth control valve (63) via pipelines. When the steering control solenoid valve (61) is energized or de-energized, the valve core moves so that its working oil port is selectively connected to the oil inlet or the oil return port, and the oil return port of the steering control solenoid valve (61) is connected to the oil return pipeline.

6. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 4, characterized in that: The third control valve (62) is a two-position, two-way solenoid valve having an oil inlet and an oil outlet. The oil inlet and the oil outlet of the third control valve (62) are connected in series to a pipeline connecting the second oil circuit and the fourth control valve (63). When the third control valve (62) is energized or de-energized, the valve core moves, thereby connecting or disconnecting the oil inlet and the oil outlet.

7. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 4, characterized in that: The fifth control valve (64) is a two-position four-way solenoid valve having an oil inlet, an oil return port and two working oil ports. The oil inlet and the oil return port of the fifth control valve (64) are connected to the first interface and the third interface respectively in a one-to-one correspondence. The two working oil ports of the fifth control valve (64) are connected to the interfaces of the two oil chambers of the double-acting steering cylinder (4) through pipelines respectively. When the fifth control valve (64) is energized or de-energized, the valve core moves, so that its oil inlet and oil return port are connected to or disconnected from the two working oil ports respectively in a one-to-one correspondence.

8. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 4, characterized in that: Filters are respectively provided upstream of pipelines connecting the second oil circuit and the two spring side chambers of the fourth control valve (63).

9. The electro-hydraulic proportional navigation control system capable of achieving fully automatic navigation according to claim 4, characterized in that: A throttle valve is provided downstream of the pipeline connecting the second oil circuit and the two spring side chambers of the fourth control valve (63).

10. A tractor, characterized in that: It comprises an electro-hydraulic proportional navigation control system capable of realizing fully automatic navigation as described in any one of claims 1 to 9.

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