A three-cylinder hydraulic control system and control method for a reversible plow

Abstract

This invention relates to the field of hydraulic control technology for reversible plows, and particularly to a three-cylinder hydraulic control system and method for reversible plows. The structure of the three-cylinder hydraulic control system includes a main control valve; a main valve connected to the main control valve; a first directional valve connected to the main valve; a second directional valve connected to the main valve; an external amplitude-adjusting cylinder connected to the second and first directional valves; a reversing cylinder connected to the first and second directional valves; a first regulating circuit connecting the main control valve and the second chamber of the reversing cylinder, and a large chamber connecting the main control valve and the reversing cylinder; an internal amplitude-adjusting cylinder connected to the main control valve; and a pilot valve connected to the throttle port of the main valve. This three-cylinder hydraulic control system and method for reversible plows solves the problem of cumbersome operation of existing reversible plows and the need for multiple adjustments to the reversing angle.

Description

Technical Field

[0001] This application relates to the field of hydraulic control technology for reversible plows, and in particular to a three-cylinder hydraulic control system and control method for reversible plows. Background Technology

[0002] As farmland is increasingly used for large-scale planting, farmers have higher and higher requirements for the efficiency and precision of operations such as tilling, sowing, and fertilizing. How to achieve efficient and precise farmland operations has become an urgent technical problem to be solved.

[0003] Currently, reversible plows on the market generally suffer from cumbersome operation. To flip the plow from one side to the other, the operator needs to manipulate the hydraulic system multiple times. Furthermore, controlling the flipping angle requires the operator to rely on experience. Consequently, when multiple adjustments to the plow are needed during operation, the operator must repeatedly adjust the flipping angle, significantly reducing tillage efficiency. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a three-cylinder hydraulic control system and control method for a reversible plow, so as to solve the problem that the operation of the existing reversible plow is relatively cumbersome and requires multiple adjustments to the reversing angle of the reversible plow.

[0005] According to a first aspect of the present invention, a three-cylinder hydraulic control system for a reversible plow is provided, wherein the three-cylinder hydraulic control system for a reversible plow includes: a main control valve; a main valve connected to the main control valve, the end of the main valve being provided with a throttle orifice; a first directional valve connected to the main valve; a second directional valve connected to the main valve; an external amplitude regulating cylinder, the large chamber of the external amplitude regulating cylinder being connected to the second directional valve, and the small chamber of the external amplitude regulating cylinder being connected to the first directional valve; a reversing cylinder, the small chamber of the reversing cylinder being provided with a limit block, the limit block dividing the small chamber of the reversing cylinder into a first cavity and a second cavity, the first cavity being close to the piston of the reversing cylinder, the second cavity being away from the piston of the reversing cylinder, the large chamber of the reversing cylinder being connected to the first directional valve, and the first cavity being connected to... The system includes: a second directional control valve; a first regulating circuit connecting the main control valve and the second chamber of the tilting cylinder, and a large chamber connecting the main control valve and the tilting cylinder; the main control valve being able to adjust the position of the limit block through the first regulating circuit to limit the stroke of the piston of the tilting cylinder; an inner amplitude regulating cylinder, the large and small chambers of which are connected to the main control valve through the second regulating circuit; and a pilot valve connected to the throttle port of the main valve; the outer amplitude regulating cylinder and the tilting cylinder being able to lock each other; the outer amplitude regulating cylinder and the tilting cylinder operating sequentially; when the outer amplitude regulating cylinder extends to its limit position and the tilting cylinder retracts to its limit position, the pilot valve switches from the second position to the first position, and the main valve switches from the first position to the second position.

[0006] Preferably, in the first regulating circuit, a limit hydraulic lock, a first filter screen, and a first flow valve are sequentially arranged in the direction away from the tilting cylinder; a first overload valve is arranged in the circuit connecting the first and second chambers of the tilting cylinder; a second overload valve, an external amplitude-adjusting hydraulic lock, and a second filter screen are arranged in the circuit connecting the large and small chambers of the external amplitude-adjusting cylinder; a second flow valve is arranged in the oil line connecting the large chamber of the external amplitude-adjusting cylinder; the second overload valve, the external amplitude-adjusting hydraulic lock, the second filter screen, and the second flow valve are arranged sequentially in the direction away from the external amplitude-adjusting cylinder; and an internal amplitude-adjusting hydraulic lock is arranged in the second regulating circuit.

[0007] Preferably, the large cavity side of the tilting cylinder is provided with an internal oil passage, the piston rod of the tilting cylinder is connected to the piston of the tilting cylinder, the piston rod is provided with a cavity, the second reversing valve is connected to the cavity through the internal oil passage, and a connecting hole is provided at the end of the piston rod near the piston, the cavity is connected to the first cavity through the connecting hole.

[0008] Preferably, when the first directional valve is in the first position, the first directional valve is connected to the small chamber of the external amplitude-adjusting cylinder and the large chamber of the tilting cylinder; when the first directional valve is in the second position, the first directional valve is connected to the small chamber of the external amplitude-adjusting cylinder; the first directional valve is provided with a first spring, and under the drive of the first spring, the first directional valve has a tendency to switch to the first position; the first directional valve is provided with a throttle orifice, and the throttle orifice is connected to the small chamber of the external amplitude-adjusting cylinder; when the external amplitude-adjusting cylinder returns oil, the first directional valve switches from the first position to the second position; when When the second directional valve is in the first position, it is connected to the large chamber of the external amplitude regulating cylinder and the first chamber of the tilting cylinder; when the second directional valve is in the second position, it is connected to the first chamber of the tilting cylinder; the second directional valve is provided with a second spring, which, driven by the second spring, tends to switch to the first position; the second directional valve is provided with a throttle orifice, which is connected to the first chamber of the tilting cylinder; when the tilting cylinder returns oil, the second directional valve switches from the first position to the second position.

[0009] Preferably, the three-cylinder hydraulic control system of the reversing plow further includes: a first hydraulic lock disposed between the large chamber of the reversing cylinder and the first directional valve, the first hydraulic lock being connected to the main valve, and the first hydraulic lock being opened when the main valve is in a first position; a second hydraulic lock disposed between the first chamber of the reversing cylinder and the second directional valve, the second hydraulic lock being connected to the main valve, and the second hydraulic lock being opened when the main valve is in a second position; a first one-way throttle valve disposed between the first hydraulic lock and the large chamber of the reversing cylinder; and a second one-way throttle valve disposed between the second hydraulic lock and the first chamber of the reversing cylinder.

[0010] Preferably, when the main valve is in the first position, the second directional valve, the first hydraulic lock, and the pilot valve are connected to the oil supply circuit of the main valve, and the first directional valve is connected to the oil return circuit of the main valve; when the main valve is in the second position, the first directional valve and the second hydraulic lock are connected to the oil supply circuit of the main valve, and the second directional valve is connected to the oil return circuit of the main valve; the main valve is provided with a third spring, and under the drive of the third spring, the main valve has a tendency to switch to the first position; when the main valve is in the second position, the throttling of the main valve... The pilot valve is connected to the oil supply circuit of the main valve, forcing the main valve to remain in the second position. When the pilot valve is in the second position, no hydraulic oil flows inside it. When the pilot valve is in the first position, hydraulic oil can flow through the pilot valve to the throttle port of the main valve, causing the main valve to switch from the first position to the second position. The pilot valve is equipped with a fourth spring, which, driven by the fourth spring, tends to switch to the second position. The pilot valve is equipped with a throttle port, which is connected to the oil supply circuit of the main valve when the main valve is in the first position.

[0011] According to a second aspect of the present invention, a control method for a three-cylinder hydraulic control system of a reversible plow is provided, wherein the three-cylinder hydraulic control system of the reversible plow is as described above, and the control method of the three-cylinder hydraulic control system of the reversible plow includes: the initial state of the outer amplitude-adjusting cylinder is a retracted state, the initial state of the reversing cylinder is an extended state, the main control valve is operated to open, then the outer amplitude-adjusting cylinder extends to its limit position, then the reversing cylinder retracts to its limit position, then the main valve is switched from a first position to a second position, then the reversing cylinder extends to its limit position, then the outer amplitude-adjusting cylinder retracts to its limit position, and finally the main control valve is operated to close; simultaneously, the main control valve controls the extension or retraction of the inner amplitude-adjusting cylinder through the second regulating circuit.

[0012] Preferably, the limit hydraulic lock is opened, and the main control valve supplies oil to the large chamber of the tilting cylinder through the first adjustment circuit, while the second chamber returns oil to the main control valve through the first adjustment circuit. This causes the piston of the tilting cylinder to push the limit block to move away from the large chamber of the tilting cylinder, thereby adjusting the stroke of the piston of the tilting cylinder. After the limit block moves to the desired position, the limit hydraulic lock is closed.

[0013] Preferably, the limiting hydraulic lock is opened, and the main control valve supplies oil to the second chamber through the first adjustment circuit. The large chamber of the tilting cylinder returns oil to the main control valve through the first adjustment circuit, causing the limiting block to move towards the large chamber of the tilting cylinder to adjust the stroke of the piston of the tilting cylinder. After the limiting block moves to the desired position, the limiting hydraulic lock is closed.

[0014] Preferably, after the main control valve is opened, hydraulic oil flows from the main control valve to the main valve. At this time, the main valve is in the first position. After passing through the main valve, the hydraulic oil is divided into three paths. The first path flows to the pilot valve, which is in the second position and not activated. The second path flows to the first hydraulic lock, causing it to open. The third path flows to the second directional valve, which is in the first position. After passing through the second directional valve, the hydraulic oil flows to the large chamber of the external amplitude regulating cylinder, forcing it to extend. The return oil from the external amplitude regulating cylinder flows to the... The throttling orifice of the first directional valve forces it to switch from the first position to the second position, then the return oil flows to the main valve, and finally to the main control valve. When the first directional valve switches to the second position, the oil passage of the large chamber of the tilting cylinder is closed. In this state, the external amplitude regulating cylinder extends to its limit position, and the tilting cylinder is closed. When the external amplitude regulating cylinder extends to its limit position, the pressure in the small chamber of the external amplitude regulating cylinder decreases, and the first directional valve switches from the second position to the first position under the action of the spring force. The hydraulic oil passes through the second directional valve and then... The second hydraulic lock and the second one-way throttle valve flow to the first chamber of the tilting cylinder, forcing the tilting cylinder to retract. The return oil from the tilting cylinder passes through the first one-way throttle valve and the first hydraulic lock to reach the first directional valve in the first position, then flows to the main valve, and finally to the main control valve. When the return oil passes through the first one-way throttle valve, pressure is generated in the first chamber of the tilting cylinder and acts on the throttle port of the second directional valve, forcing the second directional valve to switch from the first position to the second position. The oil passage of the large chamber of the external amplitude regulating cylinder is closed. In the current state, the tilting cylinder retracts to its limit position, and the external amplitude adjustment cylinder is in the closed state. When the tilting cylinder retracts to its limit position, the pressure in the hydraulic control system of the three cylinders of the tilting plow rises to the highest state. Under the action of pressure, the pilot valve switches from the second position to the first position. After the hydraulic oil passes through the pilot valve in the first position, it acts on the throttle port of the main valve, forcing the main valve to switch from the first position to the second position. Subsequently, the control hydraulic oil of the pilot valve returns through the main valve in the second position, so that the pilot valve switches from the first position to the second position under the action of spring force.When the main valve switches from the first position to the second position, the hydraulic oil is divided into three paths after passing through the main valve. The first path flows to the second hydraulic lock, opening it. The second path flows to the throttle port of the main valve, forcing it to remain in the second position. The third path flows to the first directional valve in the first position. After passing through the first directional valve, the hydraulic oil passes through the first hydraulic lock and the first one-way throttle valve, finally flowing to the large chamber of the tilting cylinder, forcing it to extend. The return oil from the first chamber of the tilting cylinder passes through the second one-way throttle valve, the second hydraulic lock, and the second directional valve, flowing to the main valve and finally to the main control valve. When the return oil passes through the second directional valve, pressure is generated in the first chamber of the tilting cylinder, acting on the throttle port of the second directional valve, forcing it to extend. When the second directional valve switches from the first position to the second position, the oil passage of the large chamber of the external amplitude-adjusting cylinder is closed. In this state, the tilting cylinder extends to its limit position, and the external amplitude-adjusting cylinder is in the closed state. When the tilting cylinder extends to its limit position, the pressure in the first chamber of the tilting cylinder decreases, and the second directional valve switches from the second position to the first position under the action of the spring force. The hydraulic oil reaches the small chamber of the external amplitude-adjusting cylinder after passing through the first directional valve in the first position. The return oil from the large chamber of the external amplitude-adjusting cylinder flows to the main valve through the second directional valve in the first position, and finally flows to the main control valve. When the main valve is in the second position, the first hydraulic lock is in the closed state, the oil passage of the large chamber of the tilting cylinder is closed, and in this state, the external amplitude-adjusting cylinder retracts to its limit position, and the tilting cylinder is in the closed state.

[0015] The three-cylinder hydraulic control system and method for the reversible plow of this invention can interlock the outer amplitude adjustment cylinder and the reversing cylinder, allowing them to operate sequentially. The outer amplitude adjustment cylinder adjusts the angle of the main beam of the reversible plow, while the reversing cylinder controls the reversing angle of the plow. When the operator opens the main control valve, the outer amplitude adjustment cylinder extends to its limit position, then the reversing cylinder retracts to its limit position. The main valve then switches from a first position to a second position, and the reversing cylinder extends to its limit position again, followed by the outer amplitude adjustment cylinder retracting to its limit position. Finally, the operator closes the main control valve, thus enabling the reversible plow to flip from one side to the other. During this process, by adjusting the position of the limit block in the reversing cylinder, the piston's stroke can be adjusted to control the reversible plow's limit reversing position, thereby avoiding multiple adjustments to the reversing angle during operation; only the piston needs to move to its limit position. Furthermore, the main control valve controls the extension or retraction of the inner amplitude adjustment cylinder through a second adjustment circuit, thereby controlling the angle of the side beam of the reversible plow. The entire process requires no cumbersome operation from the operator; only a signal from the main control valve is needed. The reversible plow's movements are smooth and continuous, significantly improving tillage efficiency. This effectively solves the problem of existing reversible plows being cumbersome to operate and requiring multiple adjustments to the plow's tilting angle.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the three-cylinder hydraulic control system for the reversible plow according to the present invention.

[0019] Figure 2 This is a schematic diagram of the tilting cylinder of the three-cylinder hydraulic control system for the tilting plow according to the present invention.

[0020] Figure 3 This is a schematic diagram of the extended state of the external amplitude adjustment cylinder of the three-cylinder hydraulic control system for the reversible plow according to the present invention.

[0021] Figure 4 This is a schematic diagram of the retracted state of the tilting cylinder in the three-cylinder hydraulic control system of the tilting plow according to the present invention.

[0022] Figure 5 This is a schematic diagram of the main valve switching of the three-cylinder hydraulic control system for the reversible plow according to the present invention.

[0023] Figure 6 This is a schematic diagram of the extended state of the tilting cylinder in the three-cylinder hydraulic control system of the tilting plow according to the present invention.

[0024] Figure 7 This is a schematic diagram of the retracted state of the external amplitude adjustment cylinder of the three-cylinder hydraulic control system of the reversible plow according to the present invention.

[0025] Figure 8 This is a schematic diagram of the position adjustment limit block of the three-cylinder hydraulic control system of the reversible plow according to the present invention.

[0026] Figure 9 This is a schematic diagram of the regulating internal amplitude oil of the three-cylinder hydraulic control system of the reversible plow according to the present invention.

[0027] Reference numerals in the attached diagram: 1-Main control valve; 2-Main valve; 3-Pilot valve; 4-First directional valve; 5-Second directional valve; 6-Second hydraulic lock; 7-Second one-way throttle valve; 8-First hydraulic lock; 9-First one-way throttle valve; 10-Second flow valve; 11-Second filter screen; 12-External amplitude adjustment hydraulic lock; 13-Second overload valve; 14-External amplitude adjustment cylinder; 15-First flow valve; 16-First filter screen; 17-Limit hydraulic lock; 18-First overload valve; 19-Tilting cylinder; 190-Internal oil passage; 191-First chamber; 192-Second chamber; 193-Piston; 194-Piston rod; 20-Internal amplitude adjustment hydraulic lock; 21-Internal amplitude adjustment cylinder; 22-Limit block; 23-First adjustment circuit; 24-Second adjustment circuit. Detailed Implementation

[0028] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0029] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0030] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0031] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0032] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0033] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0034] The terminology used herein is for the purpose of describing various examples only and is not intended to limit the examples. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0035] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0036] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0037] like Figures 1 to 9 As shown, according to a first aspect of the present invention, a three-cylinder hydraulic control system for a reversible plow is provided. The three-cylinder hydraulic control system for a reversible plow includes a main control valve 1, a main valve 2, a first directional valve 4, a second directional valve 5, an external amplitude adjustment cylinder 14, a reversing cylinder 19, a first adjustment circuit 23, an internal amplitude adjustment cylinder 21, and a pilot valve 3.

[0038] In the following description, reference will be made to Figures 1 to 9 The specific structure of the aforementioned components of the three-cylinder hydraulic control system for the reversible plow and the connection relationship of the aforementioned components are described in detail.

[0039] like Figures 1 to 9As shown, in this embodiment, the main valve 2 is connected to the main control valve 1. The main control valve 1 can be a tractor main control valve 1. When the operator opens the main control valve 1, the main control valve 1 can supply oil to the main valve 2. The end of the main valve 2 can be provided with a throttle orifice for driving the main valve 2 to switch directions. The first reversing valve 4 and the second reversing valve 5 can be connected to the main valve 2 through oil circuits respectively. The large chamber of the external amplitude regulating cylinder 14 can be connected to the second reversing valve 5, and the small chamber of the external amplitude regulating cylinder 14 can be connected to the first reversing valve 4. A limit block 22 can be provided in the small chamber of the tilting cylinder 19. The limit block 22 can divide the small chamber of the tilting cylinder 19 into a first chamber 191 and a second chamber 192. The first chamber 191 is located close to the piston 193 of the tilting cylinder 19, and the second chamber 192 is located away from the piston 193 of the tilting cylinder 19. The large chamber of the tilting cylinder 19 can be connected to the first directional valve 4, and the first chamber 191 can be connected to the second directional valve 5. The external amplitude adjustment cylinder 14 is used to adjust the angle of the main beam of the tilting plow, and the tilting cylinder 19 is used to control the tilting angle of the tilting plow. The first adjustment circuit 23 includes two oil circuits, which can be connected to the main control valve 1 and the second chamber 192 of the tilting cylinder 19, and the large chamber of the tilting cylinder 19, respectively. The main control valve 1 can adjust the position of the limit block 22 through the first adjustment circuit 23 to limit the stroke of the piston 193 of the tilting cylinder 19, thereby adjusting the extreme position that the tilting cylinder 19 can extend. The internal amplitude adjustment cylinder 21 has its large and small chambers connected to the main control valve 1 through the second adjustment circuit 24. The second adjustment circuit 24 includes two oil circuits, which can be connected to the large and small chambers of the internal amplitude adjustment cylinder 21, respectively. The internal amplitude adjustment cylinder 21 is used to adjust the angle of the side beam of the tilting plow. The pilot valve 3 can be connected to the throttle port of the main valve 2. The external amplitude adjustment cylinder 14 and the tilting cylinder 19 can be interlocked, allowing them to operate sequentially. When the external amplitude adjustment cylinder 14 extends to its limit position and the tilting cylinder 19 retracts to its limit position, the pilot valve 3 can switch from the second position to the first position, and the main valve 2 can switch from the first position to the second position. Afterward, the main valve 2 will remain in the second position to ensure that the external amplitude adjustment cylinder 14 and the tilting cylinder 19 can complete the full tilting action of the plow.

[0040] Preferred, such as Figures 1 to 9As shown, in this embodiment, a limit hydraulic lock 17, a first filter screen 16, and a first flow valve 15 can be sequentially arranged in the first regulating circuit 23 along the direction away from the tilting cylinder 19. The limit hydraulic lock 17 controls the flow of oil in the second chamber 192. When the limit hydraulic lock 17 is closed, the piston 193 cannot push the limit block 22, thus controlling the stroke of the piston 193. A first overload valve 18 is provided in the circuit connecting the first chamber 191 and the second chamber 192 of the tilting cylinder 19. A second overload valve 13, an external amplitude adjustment hydraulic lock 12, and a second filter screen 11 are provided in the circuit connecting the large and small chambers of the external amplitude adjustment cylinder 14. The external amplitude adjustment hydraulic lock 12 prevents oil from flowing out of the large chamber of the external amplitude adjustment cylinder 14 when it is under load. A second flow valve 10 can be provided in the oil line connecting the large chamber of the external amplitude adjustment cylinder 14. The second overload valve 13, the external amplitude adjustment hydraulic lock 12, the second filter screen 11, and the second flow valve 10 can be arranged sequentially in a direction away from the external amplitude adjustment cylinder 14. An internal amplitude adjustment hydraulic lock 20 can be provided on the second adjustment circuit 24 to prevent the oil in the large chamber of the internal amplitude adjustment cylinder 21 from flowing out when under load.

[0041] In this embodiment, the first flow valve 15 and the second flow valve 10 are used to control the flow rate of the oil. The first filter screen 16 is used to filter impurities in the oil to protect the external amplitude adjustment hydraulic lock 12, the second overload valve 13, and the external amplitude adjustment cylinder 14. The second filter screen 11 is used to filter impurities in the oil to protect the limit hydraulic lock 17, the first overload valve 18, and the tilting cylinder 19.

[0042] Preferred, such as Figure 1 and Figure 2 As shown, in this embodiment, the large cavity side of the tilting cylinder 19 is provided with an internal oil passage 190, which can axially penetrate the large cavity of the tilting cylinder 19. The piston rod 194 of the tilting cylinder 19 can be connected to the piston 193 of the tilting cylinder 19. The piston rod 194 can have a cavity inside. The second reversing valve 5 is connected to the internal oil passage 190 through an oil circuit, and is also connected to the cavity through the internal oil passage 190 to supply oil to the cavity. The end of the piston rod 194 near the piston 193 (which can be as follows) Figure 2 The left end (as shown) has a connecting hole that extends radially along the piston rod 194. This allows the cavity to be connected to the first cavity 191 through the connecting hole, thereby delivering the oil from the second directional valve 5 to the first cavity 191.

[0043] Preferred, such as Figures 1 to 9As shown, in the embodiment, the first position is when the main valve 2, the first directional valve 4, the second directional valve 5, and the pilot valve 3 are in the left position; the second position is when the main valve 2, the first directional valve 4, the second directional valve 5, and the pilot valve 3 are in the right position.

[0044] Preferred, such as Figures 1 to 9 As shown, in this embodiment, when the first directional valve 4 is in the first position, it is connected to the small chamber of the external amplitude-adjusting cylinder 14 and the large chamber of the tilting cylinder 19 via an oil circuit. When the first directional valve 4 is in the second position, it is only connected to the small chamber of the external amplitude-adjusting cylinder 14. The first directional valve 4 may be equipped with a first spring. Driven by the first spring, the first directional valve 4 tends to switch to the first position. The first directional valve 4 may also be equipped with a throttle orifice, which is connected to the small chamber of the external amplitude-adjusting cylinder 14. When the external amplitude-adjusting cylinder 14 returns oil, the first directional valve 4 can switch from the first position to the second position under pressure.

[0045] Preferred, such as Figures 1 to 9 As shown, in this embodiment, when the second directional valve 5 is in the first position, it is connected via an oil passage to the large chamber of the external amplitude regulating cylinder 14 and the first chamber 191 of the tilting cylinder 19 (i.e., connected via an internal oil passage 190). When the second directional valve 5 is in the second position, it is only connected to the first chamber 191 of the tilting cylinder 19. The second directional valve 5 may be equipped with a second spring, which, driven by the spring, tends to switch to the first position. The second directional valve 5 may also be equipped with a throttle orifice connected to the first chamber 191 of the tilting cylinder 19. When the tilting cylinder 19 returns oil, the second directional valve 5 can switch from the first position to the second position under pressure.

[0046] Preferred, such as Figures 1 to 9 As shown, in this embodiment, the hydraulic control system of the three cylinders of the tilting plow may further include a first hydraulic lock 8, a second hydraulic lock 6, a first one-way throttle valve 9, and a second one-way throttle valve 7. The first hydraulic lock 8 may be disposed between the large chamber of the tilting cylinder 19 and the first directional valve 4. The first hydraulic lock 8 can be connected to the main valve 2 via an oil circuit. When the main valve 2 is in the first position, the first hydraulic lock 8 is open. The second hydraulic lock 6 may be disposed between the first chamber 191 of the tilting cylinder 19 and the second directional valve 5. The second hydraulic lock 6 can be connected to the main valve 2 via an oil circuit. When the main valve 2 is in the second position, the second hydraulic lock 6 is open. The first one-way throttle valve 9 may be disposed between the first hydraulic lock 8 and the large chamber of the tilting cylinder 19. The second one-way throttle valve 7 may be disposed between the second hydraulic lock 6 and the first chamber 191 of the tilting cylinder 19.

[0047] Preferred, such as Figures 1 to 9 As shown in the embodiment, when the main valve 2 is in the first position, the second directional valve 5, the first hydraulic lock 8, and the pilot valve 3 can be connected to the oil supply circuit of the main valve 2, and the first directional valve 4 can be connected to the oil return circuit of the main valve 2. When the main valve 2 is in the second position, the first directional valve 4 and the second hydraulic lock 6 can be connected to the oil supply circuit of the main valve 2, and the second directional valve 5 can be connected to the oil return circuit of the main valve 2.

[0048] Preferred, such as Figures 1 to 9 As shown, in this embodiment, the main valve 2 may be equipped with a third spring. Driven by the third spring, the main valve 2 tends to switch to a first position. When the main valve 2 is in the second position, its throttle port can be connected to the oil supply circuit, thereby forcing the main valve 2 to remain in the second position. When the main control valve 1 stops supplying oil, the main valve 2 can switch from the second position to the first position under the drive of the third spring.

[0049] Preferred, such as Figures 1 to 9 As shown, in this embodiment, when the pilot valve 3 is in the second position, no hydraulic oil flows through it (i.e., the oil passage is blocked). When the pilot valve 3 is in the first position, hydraulic oil can flow through the pilot valve 3 to the throttle port of the main valve 2, causing the main valve 2 to switch from the first position to the second position. The pilot valve 3 may be equipped with a fourth spring. Driven by the fourth spring, the pilot valve 3 has a tendency to switch to the second position. The pilot valve 3 is also equipped with a throttle port, which is connected to the oil supply passage of the main valve 2 when the main valve 2 is in the first position. When the main valve 2 is in the second position, the hydraulic oil can force the pilot valve 3 to remain in the second position.

[0050] During use, the three-cylinder hydraulic control system of the reversible plow enables the outer amplitude adjustment cylinder 14 and the reversing cylinder 19 to operate sequentially. The operator only needs to provide signals to open and close the main control valve 1 to flip the reversible plow from one side to the other. The main control valve 1 can be manually or electro-hydraulic controlled for remote operation, offering convenience and speed. The main control valve 1 can adjust the position of the limit block 22 via the first adjustment circuit 23 to limit the stroke of the piston 193 of the reversing cylinder 19, thereby adjusting the maximum extension position of the reversing cylinder 19. This avoids the need for repeated adjustments when changing the reversing angle of the plow; the operator only needs to move the piston 193 to the limit position. The inner amplitude adjustment cylinder 21 has its large and small chambers connected to the main control valve 1 via the second adjustment circuit 24. The inner amplitude adjustment cylinder 21 is used to adjust the angle of the side beam of the reversible plow, and the outer amplitude adjustment cylinder 14 is used to adjust the angle of the main beam of the reversible plow, thereby enabling precise adjustment of the reversing angle of the reversible plow.

[0051] In addition, such as Figures 3 to 9 As shown, according to a second aspect of the present invention, a control method for a three-cylinder hydraulic control system of a reversible plow is provided. The three-cylinder hydraulic control system of the reversible plow is as described above. The control method includes: setting the initial state of the outer amplitude-adjusting cylinder 14 to a retracted state and the initial state of the reversible cylinder 19 to an extended state. In this case, the main control valve 1 is opened, and then the outer amplitude-adjusting cylinder 14 extends to its limit position; then the reversible cylinder 19 retracts to its limit position; then the main valve 2 switches from a first position to a second position; then the reversible cylinder 19 extends to its limit position; then the outer amplitude-adjusting cylinder 14 retracts to its limit position; finally, the main control valve 1 is closed. This enables a cycle, and after the entire operation is completed, the outer amplitude-adjusting cylinder 14, the reversible cylinder 19, and each hydraulic valve can return to their initial state. Simultaneously, the main control valve 1 can also control the extension or retraction of the inner amplitude-adjusting cylinder 21 through the second adjustment circuit 24 to achieve coordinated operation, ultimately causing the reversible plow to rotate to the optimal soil entry angle and working direction.

[0052] Specifically, such as Figure 3 As shown, in this embodiment, after the main control valve 1 is opened, hydraulic oil flows from the main control valve 1 to the main valve 2, which is in the first position. The hydraulic oil is divided into three paths after passing through the main valve 2. The first path flows to the pilot valve 3, which is in the second position and not activated (the oil pressure is insufficient to drive the pilot valve 3 to switch). The second path flows to the first hydraulic lock 8, opening it. The third path flows to the second directional valve 5, which is in the first position. After passing through the second directional valve 5, the hydraulic oil flows to the large chamber of the external amplitude regulating cylinder 14, forcing it to extend. The return oil from the external amplitude regulating cylinder 14 flows to the throttle port of the first directional valve 4, forcing it to switch from the first position to the second position. Then, the return oil flows to the main valve 2, and finally back to the main control valve 1. When the first directional valve 4 switches to the second position, the oil passage of the large chamber of the tilting cylinder 19 is closed. In this state, the external amplitude adjustment cylinder 14 continues to extend until it reaches its limit position, while the tilting cylinder 19 is in the closed state (i.e., the tilting cylinder 19 remains in the extended state).

[0053] Preferably, as shown in Figure 4, in this embodiment, when the external amplitude-adjusting cylinder 14 extends to its limit position, the pressure in the small chamber of the external amplitude-adjusting cylinder 14 decreases, and the first directional valve 4 switches from the second position to the first position under the action of the spring force. The hydraulic oil flowing out of the main valve 2 passes through the second directional valve 5, then through the second hydraulic lock 6 and the second one-way throttle valve 7 to the first chamber 191 of the tilting cylinder 19, forcing the tilting cylinder 19 to retract (piston 193 moves towards the large chamber). The return oil from the tilting cylinder 19 passes through the first one-way throttle valve 9 and the first hydraulic lock 8 to reach the first directional valve 4 in the first position. Then, the return oil flows to the main valve 2, and finally to the main control valve 1. When the return oil passes through the first one-way throttle valve 9, the first chamber 191 of the tilting cylinder 19 generates a large pressure, which acts on the throttle port of the second directional valve 5, forcing the second directional valve 5 to switch from the first position to the second position. At this time, the oil passage of the large chamber of the external amplitude-adjusting cylinder 14 is closed. In this state, the tilting cylinder 19 continues to retract until it reaches its limit position, and the external amplitude adjustment cylinder 14 is in the closed state (i.e., the external amplitude adjustment cylinder 14 remains in the extended state).

[0054] Preferred, such as Figure 5 As shown in the embodiment, when the tilting cylinder 19 retracts to its limit position, the oil pressure in the hydraulic control system of the three-cylinder tilting plow rises to its highest state. At this time, the pilot valve 3 can switch from the second position to the first position under the action of oil pressure. After passing through the pilot valve 3 in the first position, the hydraulic oil acts on the throttle orifice of the main valve 2, forcing the main valve 2 to switch from the first position to the second position. Subsequently, the control hydraulic oil of the pilot valve 3 returns through the main valve 2 in the second position, causing the pilot valve 3 to switch from the first position to the second position under the action of spring force. At the same time, one of the hydraulic oil streams from the main valve 2 in the second position can flow to the throttle orifice of the main valve 2, thereby forcing the main valve 2 to remain in the second position.

[0055] Preferably, as shown in Figure 6, in this embodiment, when the main valve 2 switches from the first position to the second position, the hydraulic oil is divided into three paths after passing through the main valve 2. The first path of hydraulic oil flows to the second hydraulic lock 6, causing the second hydraulic lock 6 to open. The second path of hydraulic oil flows to the throttle port of the main valve 2, forcing the main valve 2 to remain in the second position. The third path of hydraulic oil flows to the first directional valve 4, which is in the first position. After passing through the first directional valve 4, the hydraulic oil passes through the first hydraulic lock 8 and the first one-way throttle valve 9, and finally flows to the large chamber of the tilting cylinder 19, forcing the tilting cylinder 19 to extend. The return oil from the first chamber 191 of the tilting cylinder 19 flows to the main valve 2 after passing through the second one-way throttle valve 7, the second hydraulic lock 6, and the second directional valve 5, and finally flows to the main control valve 1. When the return oil passes through the second directional valve 5, the first chamber 191 of the tilting cylinder 19 will generate a large pressure and act on the throttle port of the second directional valve 5, forcing the second directional valve 5 to switch from the first position to the second position. At this time, the oil passage of the large chamber of the external amplitude adjustment cylinder 14 is closed. In this state, the tilting cylinder 19 continues to extend until it reaches its limit position, and the external amplitude adjustment cylinder 14 is in the closed state (that is, the external amplitude adjustment cylinder 14 remains in the extended state).

[0056] Preferred, such as Figure 7 As shown, in this embodiment, when the tilting cylinder 19 extends to its limit position (i.e., when the piston 193 of the tilting cylinder 19 abuts against the limit block 22), the pressure in the first chamber 191 of the tilting cylinder 19 decreases, and the second directional valve 5 switches from the second position to the first position under the action of the spring force. The hydraulic oil flowing out of the main valve 2 reaches the small chamber of the external amplitude regulating cylinder 14 after passing through the first directional valve 4 in the first position. The return oil from the large chamber of the external amplitude regulating cylinder 14 flows to the main valve 2 through the second directional valve 5 in the first position, and finally flows to the main control valve 1. When the main valve 2 is in the second position, the first hydraulic lock 8 is in the closed state, and the oil passage of the large chamber of the tilting cylinder 19 is closed. In this state, the external amplitude regulating cylinder 14 continues to retract until it retracts to the limit position, and the tilting cylinder 19 is in the closed state (i.e., the tilting cylinder 19 remains in the extended state). When the external amplitude adjustment cylinder 14 retracts to its limit position, the operator closes the main control valve 1, stopping the oil supply to the main valve 2. Subsequently, the main valve 2 returns to its first position under the force of the spring. At this time, the external amplitude adjustment cylinder 14 and the tilting cylinder 19 are also in their initial positions.

[0057] Preferred, such as Figure 8As shown, in this embodiment, when it is necessary to increase the stroke of the piston 193 of the tilting cylinder 19, the limiting hydraulic lock 17 is opened, and the main control valve 1 supplies oil to the large chamber of the tilting cylinder 19 through the first regulating circuit 23. The second chamber 192 returns oil to the main control valve 1 through the first regulating circuit 23, causing the piston 193 of the tilting cylinder 19 to push the limiting block 22 away from the large chamber of the tilting cylinder 19. This increases the stroke of the piston 193 of the tilting cylinder 19. After the limiting block 22 moves to the desired position, the limiting hydraulic lock 17 is closed. Similarly, when it is necessary to decrease the stroke of the piston 193 of the tilting cylinder 19, the limiting hydraulic lock 17 is opened, and the main control valve 1 supplies oil to the second chamber 192 through the first regulating circuit 23. The large chamber of the tilting cylinder 19 returns oil to the main control valve 1 through the first regulating circuit 23, causing the limiting block 22 to move closer to the large chamber of the tilting cylinder 19. This reduces the stroke of the piston 193 in the tilting cylinder 19. After the limit block 22 moves to the desired position, the limit hydraulic lock 17 can be closed. Since the desired tilting position of the plow body is relatively fixed when operating over a large area, to avoid repeatedly adjusting the tilting angle of the plow during the tilting process, it is only necessary to adjust the stroke of the piston 193 in the tilting cylinder 19 to the desired position. Thereafter, each time the tilting cylinder 19 extends to its limit position, it represents the desired tilting position of the plow body.

[0058] In addition, preferred, such as Figure 9 As shown, in the embodiment, during any of the above processes, the main control valve 1 can supply oil to the large or small chamber of the inner amplitude adjustment cylinder 21 through the second adjustment circuit 24 to control the extension or retraction of the inner amplitude adjustment cylinder 21, thereby enabling it to coordinate with the reversing cylinder 19 and the outer amplitude adjustment cylinder 14 to rotate the reversing plow to the optimal soil entry angle and working direction.

[0059] During operation, when the operator opens the main control valve 1, the external amplitude adjustment cylinder 14 extends to its limit position, then the tilting cylinder 19 retracts to its limit position. The main valve 2 then switches from the first position to the second position, the tilting cylinder 19 extends to its limit position again, and the external amplitude adjustment cylinder 14 retracts to its limit position. Finally, the operator closes the main control valve 1, thus enabling the reversible plow to tilt from one side to the other. The entire process requires no cumbersome operation from the operator; only signals to open and close the main control valve 1 are needed. The reversible plow's movement is smooth and continuous, greatly improving tillage efficiency. The main control valve 1 can adjust the position of the limit block 22 through the first adjustment circuit 23 to limit the stroke of the piston 193 of the tilting cylinder 19, thereby adjusting the maximum extension position of the tilting cylinder 19. This avoids the need for repeated adjustments when changing the tilting angle of the reversible plow; the operator only needs to move the piston 193 to its limit position. An inner amplitude adjustment cylinder 21 is provided, with its large and small chambers connected to the main control valve 1 via a second adjustment circuit 24. The inner amplitude adjustment cylinder 21 is used to adjust the angle of the side beam of the reversible plow, while the outer amplitude adjustment cylinder 14 is used to adjust the angle of the main beam of the reversible plow, thereby enabling precise adjustment of the reversing angle of the reversible plow.

[0060] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A three-cylinder hydraulic control system for a reversible plow, characterized in that, The three-cylinder hydraulic control system of the tilting plow includes: Main control valve; A main valve, connected to the main control valve, has a throttling orifice at its end; The first directional valve is connected to the main valve; The second directional valve is connected to the main valve; An external amplitude-adjusting cylinder, wherein the large chamber of the external amplitude-adjusting cylinder is connected to the second directional valve, and the small chamber of the external amplitude-adjusting cylinder is connected to the first directional valve; A tilting cylinder is provided with a limit block in its small cavity. The limit block divides the small cavity of the tilting cylinder into a first cavity and a second cavity. The first cavity is close to the piston of the tilting cylinder, and the second cavity is far from the piston of the tilting cylinder. The large cavity of the tilting cylinder is connected to the first reversing valve, and the first cavity is connected to the second reversing valve. The first adjustment circuit connects the main control valve to the second chamber of the tilting cylinder and the large chamber of the main control valve to the tilting cylinder. The main control valve can adjust the position of the limit block through the first adjustment circuit to limit the stroke of the piston of the tilting cylinder. An internal amplitude-adjusting cylinder, wherein the large and small chambers of the internal amplitude-adjusting cylinder are connected to the main control valve via a second adjustment circuit; and A pilot valve is connected to the throttle port of the main valve; The external amplitude adjustment cylinder and the tilting cylinder can be locked to each other. The external amplitude adjustment cylinder and the tilting cylinder operate sequentially. When the external amplitude adjustment cylinder extends to its limit position and the tilting cylinder retracts to its limit position, the pilot valve switches from the second position to the first position, and the main valve switches from the first position to the second position. On the first regulating circuit, a limit hydraulic lock, a first filter screen and a first flow valve are sequentially arranged in the direction away from the tilting cylinder, and a first overload valve is arranged on the circuit connecting the first cavity and the second cavity of the tilting cylinder. A second overload valve, an external amplitude adjustment hydraulic lock, and a second filter screen are provided on the circuit connecting the large and small chambers of the external amplitude adjustment cylinder. A second flow valve is provided on the oil line connecting the large chamber of the external amplitude adjustment cylinder. The second overload valve, the external amplitude adjustment hydraulic lock, the second filter screen, and the second flow valve are arranged sequentially in a direction away from the external amplitude adjustment cylinder. An internal amplitude-adjusting hydraulic lock is provided on the second adjustment circuit.

2. The three-cylinder hydraulic control system for the reversible plow according to claim 1, characterized in that, The large cavity side of the tilting cylinder is provided with an internal oil passage. The piston rod of the tilting cylinder is connected to the piston of the tilting cylinder. The piston rod has a cavity inside. The second reversing valve is connected to the cavity through the internal oil passage. The end of the piston rod near the piston is provided with a connecting hole. The cavity is connected to the first cavity through the connecting hole.

3. The three-cylinder hydraulic control system for the reversible plow according to claim 2, characterized in that, When the first reversing valve is in the first position, the first reversing valve is connected to the small chamber of the external amplitude regulating cylinder and the large chamber of the tilting cylinder; When the first reversing valve is in the second position, the first reversing valve is connected to the small chamber of the external amplitude regulating cylinder; The first reversing valve is provided with a first spring. Under the drive of the first spring, the first reversing valve has a tendency to switch to a first position. The first reversing valve is provided with a throttle orifice. The throttle orifice is connected to the small cavity of the external amplitude regulating cylinder. When the external amplitude regulating cylinder returns oil, the first reversing valve switches from the first position to the second position. When the second reversing valve is in the first position, the second reversing valve is connected to the large chamber of the external amplitude regulating cylinder and the first chamber of the tilting cylinder; When the second directional valve is in the second position, the second directional valve is connected to the first chamber of the tilting cylinder; The second directional valve is provided with a second spring. Driven by the second spring, the second directional valve tends to switch to the first position. The second directional valve is provided with a throttle orifice, which is connected to the first chamber of the tilting cylinder. When the tilting cylinder returns oil, the second directional valve switches from the first position to the second position.

4. The three-cylinder hydraulic control system for the reversible plow according to claim 3, characterized in that, The three-cylinder hydraulic control system for the tilting plow also includes: A first hydraulic lock is disposed between the large cavity of the tilting cylinder and the first directional valve. The first hydraulic lock is connected to the main valve. When the main valve is in the first position, the first hydraulic lock is opened. The second hydraulic lock is disposed between the first chamber of the tilting cylinder and the second directional valve. The second hydraulic lock is connected to the main valve. When the main valve is in the second position, the second hydraulic lock is opened. A first one-way throttle valve is disposed between the first hydraulic lock and the large cavity of the tilting cylinder; and The second one-way throttle valve is located between the second hydraulic lock and the first chamber of the tilting cylinder.

5. The three-cylinder hydraulic control system for the reversible plow according to claim 4, characterized in that, When the main valve is in the first position, the second directional valve, the first hydraulic lock, and the pilot valve are connected to the oil supply circuit of the main valve, and the first directional valve is connected to the oil return circuit of the main valve. When the main valve is in the second position, the first directional valve and the second hydraulic lock are connected to the oil supply circuit of the main valve, and the second directional valve is connected to the oil return circuit of the main valve. The main valve is equipped with a third spring. Driven by the third spring, the main valve tends to switch to the first position. When the main valve is in the second position, the throttle port of the main valve is connected to the oil supply circuit of the main valve, forcing the main valve to remain in the second position. When the pilot valve is in the second position, no hydraulic oil flows inside it; when the pilot valve is in the first position, hydraulic oil can flow through the pilot valve to the throttle port of the main valve, causing the main valve to switch from the first position to the second position. The pilot valve is equipped with a fourth spring. Driven by the fourth spring, the pilot valve tends to switch to the second position. The pilot valve is equipped with a throttle port. When the main valve is in the first position, the throttle port is connected to the oil supply circuit of the main valve.

6. A control method for a three-cylinder hydraulic control system of a reversible plow, characterized in that, The hydraulic control system of the three cylinders of the reversible plow is the hydraulic control system of the three cylinders of the reversible plow as described in claim 5. The control method of the hydraulic control system of the three cylinders of the reversible plow includes: the initial state of the external amplitude adjustment cylinder is the retracted state, the initial state of the reversible cylinder is the extended state, the main control valve is operated to open, then the external amplitude adjustment cylinder extends to the limit position, then the reversible cylinder retracts to the limit position, then the main valve is switched from the first position to the second position, then the reversible cylinder extends to the limit position, then the external amplitude adjustment cylinder retracts to the limit position, and finally the main control valve is operated to close. At the same time, the main control valve controls the extension or retraction of the internal amplitude regulating cylinder through the second regulating circuit.

7. The control method of the three-cylinder hydraulic control system for the reversible plow according to claim 6, characterized in that, The limit hydraulic lock is opened, and the main control valve supplies oil to the large chamber of the tilting cylinder through the first adjustment circuit. The second chamber returns oil to the main control valve through the first adjustment circuit, causing the piston of the tilting cylinder to push the limit block to move away from the large chamber of the tilting cylinder, so as to adjust the stroke of the piston of the tilting cylinder. After the limit block moves to the desired position, the limit hydraulic lock is closed.

8. The control method of the three-cylinder hydraulic control system for the reversible plow according to claim 7, characterized in that, The limit hydraulic lock is opened, and the main control valve supplies oil to the second chamber through the first adjustment circuit. The large chamber of the tilting cylinder returns oil to the main control valve through the first adjustment circuit, causing the limit block to move towards the large chamber of the tilting cylinder to adjust the stroke of the piston of the tilting cylinder. After the limit block moves to the desired position, the limit hydraulic lock is closed.

9. The control method of the three-cylinder hydraulic control system for the reversible plow according to claim 6, characterized in that, After the main control valve is opened, hydraulic oil flows from the main control valve to the main valve. At this time, the main valve is in the first position. After passing through the main valve, the hydraulic oil is divided into three paths. The first path flows to the pilot valve, which is in the second position and not activated. The second path flows to the first hydraulic lock, causing it to open. The third path flows to the second directional valve, which is in the first position. After passing through the second directional valve, the hydraulic oil flows to the large chamber of the external amplitude regulating cylinder, forcing it to extend. The return oil from the external amplitude regulating cylinder flows to the throttle port of the first directional valve, forcing it to switch from the first position to the second position. Then, the return oil flows to the main valve and finally back to the main control valve. When the first directional valve switches to the second position, the oil passage of the large chamber of the tilting cylinder is closed. In this state, the external amplitude regulating cylinder extends to its limit position, and the tilting cylinder is closed. When the external amplitude-adjusting cylinder extends to its limit position, the pressure in the small chamber of the external amplitude-adjusting cylinder decreases. Under the action of the spring force, the first directional valve switches from the second position to the first position. After passing through the second directional valve, the hydraulic oil flows through the second hydraulic lock and the second one-way throttle valve to the first chamber of the tilting cylinder, forcing the tilting cylinder to retract. The return oil from the tilting cylinder passes through the first one-way throttle valve and the first hydraulic lock to the first directional valve in the first position, then flows to the main valve, and finally flows to the main control valve. When the return oil passes through the first one-way throttle valve, the first chamber of the tilting cylinder generates pressure and acts on the throttle port of the second directional valve, forcing the second directional valve to switch from the first position to the second position. The oil passage of the large chamber of the external amplitude-adjusting cylinder is closed. In this state, the tilting cylinder retracts to its limit position, and the external amplitude-adjusting cylinder is in the closed state. When the tilting cylinder retracts to its limit position, the pressure in the hydraulic control system of the three cylinders of the tilting plow rises to its highest state. Under the action of pressure, the pilot valve switches from the second position to the first position. After the hydraulic oil passes through the pilot valve in the first position, it acts on the throttle port of the main valve, forcing the main valve to switch from the first position to the second position. Subsequently, the control hydraulic oil of the pilot valve returns through the main valve in the second position, so that the pilot valve switches from the first position to the second position under the action of spring force. When the main valve switches from the first position to the second position, the hydraulic oil is divided into three paths after passing through the main valve. The first path of hydraulic oil flows to the second hydraulic lock, causing the second hydraulic lock to open. The second path of hydraulic oil flows to the throttle port of the main valve, forcing the main valve to remain in the second position. The third path of hydraulic oil flows to the first directional valve in the first position. After passing through the first directional valve, the hydraulic oil passes through the first hydraulic lock and the first one-way throttle valve, and finally flows to the large chamber of the tilting cylinder, forcing the tilting cylinder to extend. The return oil from the first chamber of the tilting cylinder flows to the main valve after passing through the second one-way throttle valve, the second hydraulic lock, and the second directional valve, and finally flows to the main control valve. When the return oil passes through the second directional valve, the first chamber of the tilting cylinder generates pressure and acts on the throttle port of the second directional valve, forcing the second directional valve to switch from the first position to the second position. The oil passage of the large chamber of the external amplitude regulating cylinder is closed. In this state, the tilting cylinder extends to its limit position, and the external amplitude regulating cylinder is in the closed state. When the tilting cylinder extends to its limit position, the pressure in the first chamber of the tilting cylinder decreases, and the second directional valve switches from the second position to the first position under the action of the spring force. The hydraulic oil reaches the small chamber of the external amplitude regulating cylinder after passing through the first directional valve in the first position. The return oil from the large chamber of the external amplitude regulating cylinder flows to the main valve through the second directional valve in the first position, and finally flows to the main control valve. When the main valve is in the second position, the first hydraulic lock is in the closed state, the oil circuit of the large chamber of the tilting cylinder is closed, and in this state, the external amplitude regulating cylinder retracts to its limit position, and the tilting cylinder is in the closed state.

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