Hydraulic control system, method and excavator

Abstract

The application provides a hydraulic control system, method and excavator. The hydraulic control system comprises: a first oil circuit, which is communicated with a rodless cavity of a boom cylinder; a second oil circuit, which is communicated with an oil tank; a third oil circuit, which is communicated with a rod cavity of the boom cylinder; a proportional valve, which comprises an oil inlet communicated with the first oil circuit, an oil return communicated with the second oil circuit and an oil outlet communicated with the third oil circuit; wherein the proportional valve comprises a forward proportional valve and a reverse proportional valve arranged in parallel, the oil return of the forward proportional valve is kept communicated with the oil inlet, and the oil return of the reverse proportional valve is kept communicated with the oil outlet. When the boom is lowered, the hydraulic oil flowing out of the rodless cavity can flow to the oil tank through the forward proportional valve, so that the hydraulic oil can flow more and more timely into the rod cavity through the reverse proportional valve with a larger flow area, thereby preventing the boom cylinder from being sucked or exploded, avoiding causing significant damage to the hydraulic control system and elements thereof, and prolonging the service life of the hydraulic control system.

Description

Technical Field

[0001] This application relates to the field of excavator technology, specifically to a hydraulic control system, method, and excavator. Background Technology

[0002] During operation, excavators perform tasks such as digging and transferring materials by raising and lowering the boom. The boom is raised by the boom cylinder, while the boom is lowered by the hydraulic control system through the main oil circuit. Alternatively, the hydraulic control system can control some of the hydraulic oil flowing out of the rodless chamber of the boom cylinder to flow into the rod chamber of the boom cylinder.

[0003] Currently, the hydraulic oil flow from the rodless chamber to the rod chamber is achieved through the main valve of the hydraulic control system. However, the flow rate of oil supplied by the main valve to the rod chamber is relatively small. If the rod chamber is emptied during boom raising, it will result in insufficient oil supply to the rod chamber during boom lowering, which may lead to cavitation or knocking in the boom cylinder. This will cause significant damage to the hydraulic control system and its components, and shorten the service life of the hydraulic control system. Summary of the Invention

[0004] In view of this, this application provides a hydraulic control system that can prevent cavitation or knocking in the boom cylinder, avoiding significant damage to the hydraulic control system and its components, and extending the service life of the hydraulic control system. In addition, this application also provides a hydraulic control method applicable to the above-mentioned hydraulic control system, and an excavator having the above-mentioned hydraulic control system.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A hydraulic control system, comprising:

[0007] The first oil circuit is connected to the rodless chamber of the boom cylinder;

[0008] The second fuel line is connected to the fuel tank;

[0009] The third oil circuit is connected to the rod chamber of the boom cylinder;

[0010] The proportional valve includes an oil inlet connected to the first oil circuit, an oil return port connected to the second oil circuit, and an oil outlet connected to the third oil circuit.

[0011] The proportional valve includes a forward proportional valve and a reverse proportional valve arranged in parallel. The return port of the forward proportional valve is connected to the inlet port, and the return port of the reverse proportional valve is connected to the outlet port.

[0012] Optionally, in the above-mentioned hydraulic control system, the hydraulic control system includes a combined main valve, wherein the forward proportional valve and the reverse proportional valve are integrated into the combined main valve.

[0013] Optionally, in the above-mentioned hydraulic control system, the hydraulic control system includes a combined main valve, the positive proportional valve is integrated into the combined main valve, and the reverse proportional valve is set independently of the combined main valve.

[0014] Optionally, in the above hydraulic control system, the first oil circuit includes a first forward branch and a first reverse branch arranged in parallel, the oil inlet of the forward proportional valve is connected to the first forward branch, and the oil inlet of the reverse proportional valve is connected to the first reverse branch.

[0015] The return port of the reverse proportional valve is connected to the second oil circuit through the fourth oil circuit;

[0016] The third oil circuit includes a third forward branch and a third reverse branch. The oil outlet of the forward proportional valve is connected to the third forward branch, and the oil outlet of the reverse proportional valve is connected to the third reverse branch.

[0017] Optionally, in the above hydraulic control system, both the forward proportional valve and the reverse proportional valve are provided with floating oil circuits, which enable hydraulic oil to flow unidirectionally from the inlet to the outlet.

[0018] Optionally, in the above hydraulic control system, a back pressure valve is provided on the second oil line, and the back pressure valve is located between the return port of the reverse proportional valve and the oil tank.

[0019] Optionally, in the above hydraulic control system, there are four proportional valves, three of which are forward proportional valves and one is a reverse proportional valve. In the second oil circuit, the pipe section located between the return port of the reverse proportional valve and the oil tank is connected to the return port of at least one of the forward proportional valves.

[0020] Optionally, in the above-described hydraulic control system, the hydraulic control system includes a controller, which is communicatively connected to each of the proportional valves and can individually control each of the proportional valves.

[0021] A hydraulic control method, applicable to any of the hydraulic control systems described above, the method comprising the following steps:

[0022] When boom drop is detected, the proportional valve is opened and it is determined whether the proportional valve is a forward proportional valve or a reverse proportional valve.

[0023] When it is determined that the opened proportional valve includes a reverse proportional valve, and the hydraulic oil flowing out of the rodless chamber of the boom cylinder flows through the first oil circuit and the forward proportional valve to the second oil circuit, a portion of the hydraulic oil in the second oil circuit flows through the reverse proportional valve and the third oil circuit to the rod chamber of the boom cylinder.

[0024] Optionally, the above hydraulic control method further includes the following steps:

[0025] When it is determined that the opened proportional valve includes a positive proportional valve, and the hydraulic oil flowing from the rodless chamber of the boom cylinder flows to the positive proportional valve through the first oil circuit, the positive proportional valve supplies oil to the rod chamber through the floating oil circuit and the third oil circuit based on the oil quantity calculated according to the area ratio of the rodless chamber and the rod chamber.

[0026] An excavator comprising the hydraulic control system described in any of the preceding claims.

[0027] This application provides a hydraulic control system for controlling the boom cylinder of an excavator. The main component of the hydraulic control system is a proportional valve. The proportional valve is connected to the rodless chamber of the boom cylinder via a first oil circuit and to the rod chamber via a third oil circuit. It is also connected to the oil tank via a second oil circuit. Multiple proportional valves are provided and divided into two types: one type is a forward proportional valve, which connects the first and second oil circuits to allow hydraulic oil flowing from the rodless chamber to the oil tank when the boom descends; the other type is a reverse proportional valve, which connects the second and third oil circuits to allow the boom to descend... When the hydraulic oil flowing out of the rodless chamber flows into the second oil circuit, some of the hydraulic oil can flow into the third oil circuit and enter the rod chamber. Since the reverse proportional valve connects the second and third oil circuits through its return port and outlet port, this path has a large flow area. Compared with the floating oil circuit with a small flow rate integrated into the main valve in related technologies, more hydraulic oil flowing out of the rodless chamber can enter the rod chamber more promptly. This can prevent the boom cylinder from sucking in air or knocking, avoid major damage to the hydraulic control system and its components, and extend the service life of the hydraulic control system. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of the boom and boom cylinder assembly;

[0030] Figure 2 A schematic diagram of the proportional valve integrated into the main valve in the hydraulic control system provided in the embodiments of this application;

[0031] Figure 3 Schematic diagram of an independently configured reverse proportional valve in a hydraulic control system;

[0032] Figure 4 A flowchart of a hydraulic control method provided in an embodiment of this application.

[0033] exist Figures 1-3 middle:

[0034] 1-Boom, 2-Boom cylinder, 3-First oil circuit, 4-Second oil circuit, 5-Third oil circuit, 6-Oil tank, 7-Forward proportional valve, 8-Reverse proportional valve, 9-Floating oil circuit, 10-Fourth oil circuit;

[0035] 21- Rodless cavity, 22- Rod cavity, 31- First forward branch, 32- First reverse branch, 51- Third forward branch, 52- Third reverse branch. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] like Figures 1-3 As shown, this application embodiment provides a hydraulic control system that can be installed in an excavator to control the lifting and lowering of at least the excavator's boom 1. Since the lifting and lowering of the boom 1 is driven by the boom cylinder 2, the hydraulic control system specifically controls the boom cylinder 2. The hydraulic control system mainly includes a proportional valve, a first oil circuit 3, a second oil circuit 4, and a third oil circuit 5. The proportional valve is the main component in the hydraulic control system that controls the boom cylinder 2, and it includes an inlet, an outlet, a return port, and a pressure port. Figure 2 In this application, the oil outlet, oil inlet, oil return, and pressure port are labeled A, B, T, and P, respectively. Based on this, multiple proportional valves are connected in parallel, such as two, three, four, or more. Figure 2The example demonstrates the setup using four proportional valves, categorized into two types: forward proportional valves (7) and reverse proportional valves (8). The difference lies in their connection: the return port T and inlet port B of the forward proportional valve 7 are continuously connected, with adjustable openings, ensuring uninterrupted connection during boom 1 descent. Similarly, the return port T and outlet port A of the reverse proportional valve 8 are continuously connected, with adjustable openings, again ensuring uninterrupted connection during boom 1 descent. Furthermore, the number of forward and reverse proportional valves (7 and 8) is not limited, provided the hydraulic control system functions correctly. For instance, with four proportional valves, there could be one, two, or three reverse proportional valves (8). Figure 2 In this example, a reverse proportional valve 8 is set among four proportional valves. The first oil circuit 3 connects the rodless chamber 21 of the boom cylinder 2 to the oil inlet B of each proportional valve. When the boom 1 descends, the piston rod of the boom cylinder 2 retracts into the cylinder body, and the hydraulic oil in the rodless chamber 21 of the boom cylinder 2 flows outward, while the rod chamber 22 needs to be injected with hydraulic oil. After the hydraulic oil in the rodless chamber 21 flows out, it enters the first oil circuit 3, and then enters the proportional valve through the oil inlet B. The second oil circuit 4 is connected to the oil tank 6, that is, the second oil circuit 4 is the return oil circuit. Since the oil inlet B and the return oil outlet T of the forward proportional valve 7 are always connected, the hydraulic oil can flow into the second oil circuit 4 through the forward proportional valve 7 after entering the oil inlet B, and then flow to the oil tank 6. The third oil circuit 5 connects the rod chamber 22 of the boom cylinder 2 to the oil outlet A of each proportional valve, and is used to supply hydraulic oil to the rod chamber when the boom 1 descends. When the hydraulic oil flowing out of the rodless chamber 21 enters the second oil circuit 4 and flows in the second oil circuit 4, since the return port T of the reverse proportional valve 8 is connected to the second oil circuit 4 and the return port T of the reverse proportional valve 8 is always connected to the outlet port A, a part of the hydraulic oil flowing in the second oil circuit 4 will enter the reverse proportional valve 8 and finally enter the rod chamber 22 through the third oil circuit 5. In this way, the hydraulic oil discharged from the rodless chamber 21 of the boom cylinder 2 flows into the rod chamber 22 of the boom cylinder 2. At the same time, since there is back pressure in the oil tank 6, the hydraulic oil in the second oil circuit 4 can flow into the rod chamber 22 preferentially, fully and timely under the action of back pressure, ensuring that the hydraulic oil entering the rod chamber 22 has a certain pressure. The excess hydraulic oil in the second oil circuit 4 that does not enter the reverse proportional valve 8 will continue to flow into the oil tank 6 along the second oil circuit 4.

[0038] The aforementioned hydraulic control system, by configuring some proportional valves as reverse proportional valves 8 with opposite oil guiding directions, enables hydraulic oil to flow from the rodless chamber 21 to the rod chamber 22. Furthermore, the reverse oil passage of the reverse proportional valve 8 is formed by connecting the return port T, the internal space of the valve, and the outlet port A of the proportional valve, increasing the flow area. Its flow rate of guided hydraulic oil is greater than that of the floating oil circuit integrated into the main valve in existing technologies. This allows more hydraulic oil flowing from the rodless chamber 21 to enter the rod chamber 22 more promptly, thereby preventing cavitation or knocking in the boom cylinder 2, avoiding significant damage to the hydraulic control system and its components, ensuring the controllability and rigidity of the hydraulic control system, and extending its service life. Moreover, using this method eliminates the need for the hydraulic control system to actively supply oil through the main oil circuit. During boom 1 descent, the flow of the main oil circuit is no longer occupied, and the flow of the main oil circuit can be used entirely for other actions, thus enabling compound operations and improving overall work efficiency. Simultaneously, it avoids throttling losses and does not increase energy consumption.

[0039] In addition, in the prior art, since the flow rate of the floating oil circuit is relatively small, in order to avoid the occurrence of cavitation or knocking, an additional oil source needs to be provided to the rod chamber 22, which will generate throttling losses and also lead to additional energy loss. However, this application does not require such a setting, thus saving energy consumption.

[0040] In this application, the proportional valve can be configured in various ways. In one optional embodiment, such as... Figure 2 As shown, the preferred hydraulic control system includes a combined main valve, with a forward proportional valve 7 and a reverse proportional valve 8 integrated within it. That is, by integrating the forward proportional valve 7 and the reverse proportional valve 8 onto the main valve of the hydraulic control system, a more compact combined main valve is formed within the hydraulic control system, which facilitates the setup of the hydraulic control system. Furthermore, in the prior art, there are already combined main valves that integrate proportional valves into the main valve. The difference between these and the combined main valve integrating the forward proportional valve 7 and the reverse proportional valve 8 in this application is that the integrated proportional valves are all forward proportional valves 7, and there is no reverse proportional valve 8. Therefore, improving the combined main valves of the prior art can directly yield a combined main valve including the forward proportional valve 7 and the reverse proportional valve 8, which is beneficial for valve forming and makes the technical solution easier to implement.

[0041] Alternatively, in another optional embodiment, the forward proportional valve 7 is integrated into the main combined valve, while the reverse proportional valve 8 is set independently of the main combined valve. That is, an external valve solution achieves the same effect as the above-described integrated solution; that is, the reverse proportional valve 8 is moved outside the main combined valve, allowing it to exist independently of it. The structure of the externally moved reverse proportional valve 8 and its interaction with other forward proportional valves 7 remain the same as described above. This allows for flexible selection of the model and location of the reverse proportional valve 8 according to actual operational requirements.

[0042] Based on the independent setting of the reverse proportional valve 8, such as Figure 3 As shown, the reverse proportional valve 8 is configured to cooperate with the first oil circuit 3, the second oil circuit 4, and the third oil circuit 5 as follows: The first oil circuit 3 includes a first forward branch 31 and a first reverse branch 32 connected in parallel. The oil inlet B of the forward proportional valve 7 is connected to the first forward branch 31, and the oil inlet B of the reverse proportional valve 8 is connected to the first reverse branch 32. The oil return port T of the reverse proportional valve 8 is connected to the second oil circuit 4 through the fourth oil circuit 10. The third oil circuit 5 includes a third forward branch 51 and a third reverse branch 52 (there is no second forward branch or second reverse branch in this application). The oil outlet A of the forward proportional valve 7 is connected to the third forward branch 51, and the oil outlet A of the reverse proportional valve 8 is connected to the third reverse branch 52. In this structure, to accommodate the independently configured reverse proportional valve 8, the first oil passage 3 and the third oil passage 5 are each divided into two branches to connect the forward proportional valve 7 and the reverse proportional valve 8, respectively. A fourth oil passage 10 is added to connect the return port T of the reverse proportional valve 8 and the second oil passage 4, allowing the lubricating oil in the second oil passage 4 to flow smoothly into the reverse proportional valve 8. During operation, the hydraulic oil flowing out of the rodless chamber 21 simultaneously enters the first forward branch 31 and the first reverse branch 31. In path 32, the hydraulic oil enters the forward proportional valve 7 via the first forward branch 31 and the reverse proportional valve 8 via the first reverse branch 32. The hydraulic oil entering the reverse proportional valve 8 can flow back to the rod chamber 22 through the floating oil path described later. Part of the hydraulic oil flowing from the forward proportional valve 7 into the second oil path 4 will enter the fourth oil path 10 before flowing back to the oil tank 6, and enter the return port T of the reverse proportional valve 8 through the guide of the fourth oil path 10, and then flow into the third reverse branch 52, and finally enter the rod chamber 22.

[0043] Furthermore, such as Figure 2As shown, both the forward proportional valve 7 and the reverse proportional valve 8 provided in this application are equipped with a floating oil passage 9, which enables hydraulic oil to flow unidirectionally from the oil inlet B to the oil outlet A. This configuration allows the proportional valve to also have a floating function, making it a floating valve as well. When an integrated solution is used, the combined main valve can be a combined main valve with a series of integrated floating functions, thus forming an internal floating valve group. During the descent of boom 1, the hydraulic oil in the rodless chamber 21 flows to the oil tank 6 through the forward proportional valve 7 of the combined main valve. However, due to the area ratio between the rod chamber 22 and the rodless chamber 21 of boom cylinder 2, i.e., when boom 1 descends, the amount of oil returning from the rodless chamber 21 is greater than the amount of oil entering the rod chamber 22, the floating function of the combined main valve is activated, and the reverse proportional valve 8 is in the open state. Part of the hydraulic oil flowing to the oil tank 6 in the second oil circuit 4 can enter the rod chamber 22 through the reverse proportional valve 8. At the same time, part of the hydraulic oil entering the inlet B can also flow to the outlet A through the floating oil circuit 9, and then enter the rodless chamber through the third oil circuit 5. When an external valve solution is used, the independently set valve is the external floating valve.

[0044] In the aforementioned hydraulic control system, because the oil tank 6 has back pressure, there is no need to specifically set the back pressure during the process of hydraulic oil flowing from the second oil circuit 4 to the reverse proportional valve 8. The back pressure in the oil tank 6 and the second oil circuit 4 (which serves as the return oil circuit) is sufficient to allow the hydraulic oil to enter the reverse proportional valve 8 and then the rod chamber 22, where it experiences a certain pressure. Furthermore, because the reverse proportional valve 8 provides a large flow area for the hydraulic oil to flow into the rod chamber 22, the hydraulic oil can smoothly flow into the rod chamber 22 under relatively low back pressure. This reduces the original back pressure in the hydraulic control system. With reduced back pressure, the hydraulic control system can be more energy-efficient and efficient when controlling the excavator for other operations, thus improving work efficiency. Alternatively, in this application, a back pressure valve (not shown in the figure) can be added to the second oil circuit 4, positioned between the return port T of the reverse proportional valve 8 and the oil tank 6. This allows the hydraulic oil to enter the rod chamber 22 more fully and promptly under greater back pressure.

[0045] The hydraulic control system includes a controller that communicates with each proportional valve and can control each valve individually. The controller is a PLC, which performs different functions by individually controlling the forward proportional valve 7 and the reverse proportional valve 8. During the descent of the boom 1, the PLC controls the forward proportional valve 7 and the reverse proportional valve 8 respectively, so that the hydraulic oil flowing out of the rodless chamber 21 can flow to the oil tank 6 through the forward proportional valve 7 and to the rod chamber 22 through the reverse proportional valve 8.

[0046] In a preferred embodiment, such as Figure 2As shown, four proportional valves are configured, three of which are forward proportional valves 7 and one is a reverse proportional valve 8. On the second oil circuit 4, the pipe section between the return port T of the reverse proportional valve 8 and the oil tank 6 is connected to the return port T of at least one forward proportional valve 7. In other words, while one of the four proportional valves is configured as a reverse proportional valve 8 and the remaining three as forward proportional valves 7, the reverse proportional valve 8 is positioned away from the oil tank 6. That is, at least one forward proportional valve 7 is located between the reverse proportional valve 8 and the oil tank 6. This allows the hydraulic oil in the rod chamber 22 to preferentially enter the reverse proportional valve 8 from either the path leading to the oil tank 6 or the path leading to the reverse proportional valve 8 when it flows to the return port T of the reverse proportional valve 8. This achieves rapid descent of the boom 1 while preventing cavitation or knocking.

[0047] In the aforementioned hydraulic control system, all proportional valves are intelligently controlled by a controller. The controller's algorithm is matched with the opening characteristics of the main valve, the relevant dimensions of the cylinder, and the size of the excavation load, thereby maximizing controllability and operational efficiency. Based on this, this application also provides a hydraulic control method applicable to the aforementioned hydraulic control system, such as... Figure 4 As shown, the method includes the following steps:

[0048] When the controller detects that boom 1 is falling, it opens the proportional valve (when an integrated solution is used, it controls the opening of the main valve of the control combination) and determines whether the opened proportional valve is the forward proportional valve 7 or the reverse proportional valve 8.

[0049] When it is determined that the open proportional valve includes the reverse proportional valve 8, the hydraulic oil flowing out of the rodless chamber 21 of the boom cylinder 2 flows to the oil tank 6 through the first oil circuit 3, the forward proportional valve 7, and the second oil circuit 4. Some of the hydraulic oil flowing into the second oil circuit 4 will flow to the rod chamber 22 of the boom cylinder 2 through the reverse proportional valve 8 and the third oil circuit 5 (when the reverse proportional valve 8 is set independently, the hydraulic oil in the second oil circuit 4 will flow through the fourth oil circuit 10 and the third reverse branch 52), while the excess hydraulic oil in the second oil circuit 4 flows into the oil tank 6.

[0050] Furthermore, as mentioned above, when the positive proportional valve 7 also has a floating oil circuit 9, the control method corresponding to this case further includes the following steps:

[0051] When it is determined that the open proportional valve includes the positive proportional valve 7, the hydraulic oil flowing out from the rodless chamber 21 of the boom cylinder 2 flows to the positive proportional valve 7 through the first oil passage 3. The positive proportional valve 7 supplies oil to the rod chamber 22 through the floating oil passage 9 and the third oil passage 5 based on the oil quantity calculated according to the area ratio of the rodless chamber 21 and the rod chamber 22. Specifically, when the controller detects that the forward proportional valve 7 and / or the reverse proportional valve 8 are equipped with floating oil circuits 9, it controls the floating oil circuits 9 to open and calculates the flow rate required for the boom 1 to descend. This ensures that the hydraulic oil flowing from the rodless chamber 21 of the boom cylinder 2 enters the inlet B and then flows through the floating oil circuit 9 to the outlet A. When the reverse proportional valve 8 is also equipped with a floating oil circuit 9, the hydraulic oil in the rodless chamber 21 flows through the return port T of the reverse proportional valve 8 to the outlet A, while simultaneously flowing through the floating oil circuit 9 from the inlet B to the outlet A. In other words, the path of the hydraulic oil flowing to the rod chamber 22 is a dual path. This allows for a more sufficient and timely supply of oil to the rod chamber 22, and better avoids the occurrence of air intake or knocking.

[0052] In specific operations, such as Figure 4 As shown, when the controller detects the boom lowering, that is, when the controller detects the operator performing the boom lowering operation on the handle, the controller calculates the hydraulic oil flow required for boom lowering based on the handle opening size (i.e., the handle movement distance). Then, as mentioned above, the hydraulic oil flows through the forward proportional valve 7 and / or the reverse proportional valve 8. The process of the hydraulic oil flowing through the reverse proportional valve 8 is as described above when the reverse proportional valve 8 is opened. When the hydraulic oil flows through the forward proportional valve 7, the controller needs to calculate the flow required for boom lowering again, and calculate the flow of the rodless chamber 21 and the rod chamber 22 based on the area ratio of the rodless chamber 21 and the rod chamber 22 respectively. Then, the controller calculates the opening size (i.e., opening degree) of the floating oil circuit 9 of the forward proportional valve 7 based on the required pressure of the rodless chamber 21 and the rod chamber 22. Subsequently, if the hydraulic oil flows to the rod chamber 22 via the floating oil circuit 9 of the forward proportional valve 7 or the reverse proportional valve 8, the controller converts the calculation result, which exists in the form of an electrical signal, into an opening parameter. Then, it transmits the opening position information (i.e., the opening parameter) to the forward proportional valve 7 at least, and causes the floating oil circuit 9 to open to the corresponding opening degree until the boom descent action ends.

[0053] In addition, this application also provides an excavator that includes the aforementioned hydraulic control system. Since the excavator includes the aforementioned hydraulic control system, the beneficial effects of the hydraulic control system on the excavator are as described above and will not be repeated here.

[0054] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0055] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0056] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0057] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0058] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0059] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A hydraulic control system, characterized in that, include: The first oil circuit is connected to the rodless chamber of the boom cylinder; The second fuel line is connected to the fuel tank; The third oil circuit is connected to the rod chamber of the boom cylinder; The proportional valve includes an oil inlet connected to the first oil circuit, an oil return port connected to the second oil circuit, and an oil outlet connected to the third oil circuit. The proportional valve includes a forward proportional valve and a reverse proportional valve arranged in parallel. The return port of the forward proportional valve is connected to the inlet port, and the return port of the reverse proportional valve is connected to the outlet port. In the second oil line, between the return port of the reverse proportional valve and the oil tank, it is connected to the return port of at least one of the forward proportional valves.

2. The hydraulic control system according to claim 1, characterized in that, The hydraulic control system includes a combined main valve, in which the forward proportional valve and the reverse proportional valve are integrated.

3. The hydraulic control system according to claim 1, characterized in that, The hydraulic control system includes a combined main valve, the positive proportional valve is integrated into the combined main valve, and the reverse proportional valve is set independently of the combined main valve.

4. The hydraulic control system according to claim 3, characterized in that: The first oil circuit includes a first forward branch and a first reverse branch arranged in parallel. The oil inlet of the forward proportional valve is connected to the first forward branch, and the oil inlet of the reverse proportional valve is connected to the first reverse branch. The return port of the reverse proportional valve is connected to the second oil circuit through the fourth oil circuit; The third oil circuit includes a third forward branch and a third reverse branch. The oil outlet of the forward proportional valve is connected to the third forward branch, and the oil outlet of the reverse proportional valve is connected to the third reverse branch.

5. The hydraulic control system according to claim 1 or 2, characterized in that, Both the forward proportional valve and the reverse proportional valve are equipped with floating oil passages, which allow hydraulic oil to flow unidirectionally from the inlet to the outlet.

6. The hydraulic control system according to claim 1, characterized in that, A back pressure valve is provided on the second oil line, and the back pressure valve is located between the return port of the reverse proportional valve and the oil tank.

7. The hydraulic control system according to claim 1, characterized in that, There are four proportional valves, three of which are positive proportional valves and one is a negative proportional valve.

8. The hydraulic control system according to claim 7, characterized in that, The hydraulic control system includes a controller that is communicatively connected to each of the proportional valves and can individually control each of the proportional valves.

9. A hydraulic control method, characterized in that, The method, applicable to any one of claims 1-8, comprises the following steps: When boom drop is detected, the proportional valve is opened and it is determined whether the proportional valve is a forward proportional valve or a reverse proportional valve. When it is determined that the opened proportional valve includes a reverse proportional valve, and the hydraulic oil flowing out of the rodless chamber of the boom cylinder flows through the first oil circuit and the forward proportional valve to the second oil circuit, a portion of the hydraulic oil in the second oil circuit flows through the reverse proportional valve and the third oil circuit to the rod chamber of the boom cylinder.

10. The hydraulic control method according to claim 9, characterized in that, It also includes the following steps: When it is determined that the opened proportional valve includes a positive proportional valve, and the hydraulic oil flowing from the rodless chamber of the boom cylinder flows to the positive proportional valve through the first oil circuit, the positive proportional valve supplies oil to the rod chamber through the floating oil circuit and the third oil circuit based on the oil quantity calculated according to the area ratio of the rodless chamber and the rod chamber.

11. An excavator, characterized in that, The hydraulic control system includes any one of claims 1-8.

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