Electro-hydraulic control valve, valve plate and control method for multi-pump system

Abstract

The application discloses a kind of electro-hydraulic control valve for multi-pump system, valve piece of electro-hydraulic control valve is integrated with cut-off combined valve and main control valve core, valve piece is provided with oil inlet, first working port, second working port, oil inlet combined oil channel and oil return oil channel communicated with oil return port;Cut-off combined valve at least includes first working position, second working position and third working position, when cut-off combined valve is located in first working position, the oil inlet of cut-off combined valve is communicated with first port, and unloads to oil return oil channel;When cut-off combined valve is located in second working position, the oil inlet of cut-off combined valve is communicated with second port, and oil is supplied to main control valve core;When cut-off combined valve is located in third working position, the oil inlet of cut-off combined valve is communicated with third port, and combined oil supply to oil inlet combined oil channel is realized;The oil inlet of main control valve core is connected to oil inlet combined oil channel, the oil return port of main control valve core is connected to oil return oil channel, and the first port and second port of main control valve core are connected to two working ports of valve piece respectively.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering machinery hydraulics, and in particular relates to an electro-hydraulic control valve, a valve plate and a control method for a multi-pump system. Background Art

[0002] With the increasing electrification of the construction machinery industry, various OEMs have launched their own electric construction machinery products to reduce the output power of individual pumps and improve overall machine efficiency. The application scope of multi-pump hydraulic systems is also gradually expanding. Currently, most construction machinery hydraulic multi-way valves on the market use single or dual pump oil supply, which presents problems such as multiple actuator load coupling, large energy losses, and limited control freedom. As a result, very few hydraulic valves are suitable for multi-pump hydraulic systems.

[0003] The multi-way valves currently used in construction machinery mainly include integral multi-way valves and disc multi-way valves. The main valve is generally designed with one or two oil inlets in the oil inlet joint, and the main relief valve, LS relief valve, pressure cut-off valve, etc. are integrated as needed. The working joint is generally equipped with A and B working oil ports, and the port relief valve, one-way valve, LS shuttle valve, LS relief valve, load holding valve, etc. are integrated as needed. The electric proportional flow cut-off valve is integrated in front of the main valve core, which can flexibly control the flow to each actuator according to actual needs. The end caps at both ends of the valve core are integrated with electric proportional pressure reducing valves to realize electro-hydraulic drive control. The existing technology has the following defects:

[0004] (1) In the existing technical solution, each actuator shares the same oil inlet channel, resulting in pressure coupling during compound actions and serious energy waste due to load differences;

[0005] (2) The existing technical solutions are applicable to single-pump or dual-pump systems. For multi-pump hydraulic systems with three or more pumps, the main valves need to be used in combination or significantly improved before they can be applied, which takes up a large space and requires more pipeline connections. Summary of the Invention

[0006] Purpose: In view of at least one of the above technical problems, the present invention provides an electro-hydraulic control valve, valve plate and control method for a multi-pump system.

[0007] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is:

[0008] In a first aspect, an electro-hydraulic control valve disc is provided, which integrates a shut-off and merging valve and a main control valve core, wherein the valve disc is provided with an oil inlet, a first working port, a second working port, an oil inlet and merging oil channel, and an oil return oil channel connected to an oil return port R;

[0009] The oil inlet of the cut-off and combination valve is connected with the oil inlet, the first port of the cut-off and combination valve is connected with the oil return channel and the oil return port of the main control valve core respectively, the second port of the cut-off and combination valve is connected with the oil inlet of the main control valve core, and the third port of the cut-off and combination valve is connected with the oil combination channel.

[0010] The main control valve core is provided with an oil inlet, an oil return port, a first port and a second port, the oil inlet of the main control valve core is further connected to the oil combination channel, the oil return port of the main control valve core is connected to the oil return channel, the first port of the main control valve core is connected with the first working port, and the second port of the main control valve core is connected with the second working port.

[0011] As another embodiment, an electro-hydraulic control valve disc is integrated with a cut-off and combination valve and a main control valve core, and the valve disc is provided with an oil inlet, a first working port, a second working port, an oil combination channel and an oil return channel communicated with an oil return port.

[0012] The cut-off and combination valve is composed of a pressure cut-off valve and a combination valve, the oil inlets of the pressure cut-off valve and the combination valve are connected with the oil inlet, the outlet of the pressure cut-off valve is connected with the oil return channel and the oil return port of the main control valve core respectively, the first port of the combination valve is connected with the oil inlet of the main control valve core, and the second port of the combination valve is connected with the oil combination channel; when the pressure cut-off valve is in the first working position, the oil inlet of the pressure cut-off valve is not communicated with the outlet; when the pressure cut-off valve is in the second working position, the oil inlet of the pressure cut-off valve is communicated with the outlet.

[0013] When the combination valve is in the first working position, the oil inlet of the combination valve is communicated with the first port; when the combination valve is in the second working position, the oil inlet of the combination valve is communicated with the second port.

[0014] The main control valve core is provided with an oil inlet, an oil return port, a first port and a second port, the oil inlet of the main control valve core is further connected to the oil combination channel, the oil return port of the main control valve core is connected to the oil return channel, the first port of the main control valve core is connected with the first working port, and the second port of the main control valve core is connected with the second working port.

[0015] In some embodiments, the electro-hydraulic control valve disc further comprises a first one-way valve, and the oil combination channel supplies oil to the main control valve core through the first one-way valve.

[0016] In some embodiments, the electro-hydraulic control valve plate further includes a main overflow valve, which is arranged between the oil inlet and the oil return channel.

[0017] In some embodiments, the electro-hydraulic control valve plate also includes a first port overflow valve and a second port overflow valve. The first port overflow valve is arranged between the first working port A and the return oil channel, and the second port overflow valve is arranged between the second working port and the return oil channel.

[0018] In some embodiments, the electro-hydraulic control valve disc further includes a load holding valve, and the first port of the main control valve core is connected to the first working port through the load holding valve.

[0019] In some embodiments, the electro-hydraulic control valve plate further includes a second one-way valve, which is arranged between the oil inlet P and the oil inlet of the main control valve core, and is used to supply oil to the main control valve core in a one-way manner through the cut-off and merging valve.

[0020] In the second aspect, the present invention also provides an electro-hydraulic control valve, comprising a plurality of working links, wherein the working links adopt the electro-hydraulic control valve valve plate, the return oil channels of the plurality of working links are connected and share a return oil port, and the oil inlet and merging oil channels of the plurality of working links are directly or indirectly connected.

[0021] In some embodiments, the electro-hydraulic control valve, the multiple working links include a bucket link and a boom link, the first working port and the second working port of the bucket link are used to connect to the bucket cylinder, and the first working port and the second working port of the boom link are used to connect to the boom cylinder; the oil inlet merging oil passages of the bucket link and the boom link are connected;

[0022] When the boom moves alone, the boom joint cut-off merging valve is controlled to open to the second working position, and the boom joint oil inlet supplies oil to the boom joint main control valve core through the boom joint cut-off merging valve; at the same time, the bucket joint cut-off merging valve is controlled to open to the third working position, and the bucket joint oil inlet supplies oil to the boom joint flow through the boom joint cut-off merging valve and the oil inlet merging oil channel to ensure the boom speed requirement;

[0023] When the bucket moves alone, the bucket joint cut-off merging valve is controlled to open to the second working position, and the oil inlet of the bucket joint supplies oil to the main control valve core of the bucket joint through the bucket joint cut-off merging valve; at the same time, the boom joint cut-off merging valve is controlled to open to the third working position, and the oil inlet of the boom joint supplies oil to the bucket joint through the boom joint cut-off merging valve and the oil inlet merging oil channel to ensure the bucket speed requirement;

[0024] When the boom and bucket are in combined motion, the bucket joint cut-off merging valve and the boom joint cut-off merging valve are both controlled to open to the second working position. The oil inlet of the bucket joint supplies oil to the main control valve core of the bucket joint through the bucket joint cut-off merging valve, and the oil inlet of the boom joint supplies oil to the main control valve core of the boom joint through the boom joint cut-off merging valve. The oil sources of the bucket joint and the boom joint are independent of each other and there is no load coupling.

[0025] When in standby state, the bucket joint cut-off merging valve and the boom joint cut-off merging valve are both in the first working position, the oil inlet of the bucket joint is unloaded through the bucket joint cut-off merging valve, and the oil inlet of the boom joint is unloaded through the boom joint cut-off merging valve, reducing the output pressure of the main pump and reducing system energy loss.

[0026] In other embodiments, the electro-hydraulic control valve, the multiple working links include a first boom link, a right traveling link, a left traveling link, a first dipper link, a second boom link, a bucket link, and a second dipper link in sequence; the return oil passages of the first boom link, the right traveling link, the left traveling link, the first dipper link, the second boom link, the bucket link, and the second dipper link are all connected to the return oil port of the first boom link, the first boom link is connected to the oil inlet merging oil passage of the right traveling link, the left traveling link is connected to the oil inlet merging oil passage of the first dipper link, and the second boom link, the bucket link, and the second dipper link are connected to the oil inlet merging oil passage;

[0027] The oil outlet of the first process valve is connected to the oil inlet of the right travel control valve core, which is used to supply oil to the right travel control valve core; the first port of the linear travel valve is connected to the oil inlet of the left travel control valve core, and the second port is connected to the oil inlet merging oil channel of the left travel link; when the linear travel valve is in the first working position, the oil inlet, the first port and the second port are not connected to each other; when the linear travel valve is in the second working position, the oil inlet and the first port are connected to supply oil to the left travel control valve core; when the linear travel valve is in the third working position, the oil inlet and the second port are connected, and the oil inlets of the first process valve, the linear travel valve and the second boom cut-off merging valve are connected.

[0028] In a third aspect, a hydraulic system for engineering machinery is provided, configured with any of the above-mentioned electro-hydraulic control valves.

[0029] Beneficial effects: The present invention provides an electro-hydraulic control valve, valve plate and control method for a multi-pump system. The present invention proposes an electro-hydraulic control valve for a multi-pump system, wherein the valve plate is provided with an independent oil inlet, an integrated overflow valve and a cut-off and merging valve. Each valve plate can be used as an independent control valve, making the system layout more flexible. The control valve can also be installed near the actuator as needed to improve the response speed. A plurality of valve plates can be combined to be used as a plate-type multi-way valve, which is suitable for hydraulic systems such as electric excavators and electric loaders. The valve plate is provided with a cut-off and merging valve, which can realize the free switching between independent oil supply for compound actions and combined oil supply for single actions, effectively reducing the output power of a single pump, eliminating the energy waste caused by load coupling, and having a high degree of control freedom. The valve plate is modularly and independently designed, with a simple structure and flexible layout, which facilitates the realization of pump and valve integrated design. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the principle of the valve plate of the electro-hydraulic control valve for a multi-pump system according to one embodiment of the present invention;

[0031] Figure 2 Schematic diagram of a first variation of the principle of the valve disc of the electro-hydraulic control valve according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of a second variation of the principle of the valve disc of the electro-hydraulic control valve according to an embodiment of the present invention;

[0033] Figure 4 Schematic diagram of a two-way electro-hydraulic control valve for a loader hydraulic system according to one embodiment of the present invention;

[0034] Figure 5 Schematic diagram of a seven-way electro-hydraulic control valve for a hydraulic system of an electric excavator according to one embodiment of the present invention;

[0035] Reference numerals: Figures 1 to 3 Middle: main relief valve 01, cut-off and combining valve 02, main control valve core 03, second port relief valve 04 and first port relief valve 05, load holding valve 06, first check valve 07, second check valve 08; pressure cut-off valve 021, combining valve 022;

[0036] Figure 4 Middle: bucket connection main relief valve 101, bucket connection shut-off and combining valve 102, bucket connection main control valve core 103, bucket connection first port relief valve 104 and bucket connection second port relief valve 105, bucket connection first check valve 107 and bucket connection second check valve 108; boom connection main relief valve 201, boom connection shut-off and combining valve 202, boom connection main control valve core 203, boom connection first port relief valve 204 and boom connection second port relief valve 205, boom load holding valve 206, boom first check valve 207, boom second check valve 208;

[0037] Figure 5 Middle: First boom main relief valve 1, first dipper arm main relief valve 2, bucket main relief valve 3, first boom cut-off merging valve 4, first dipper arm cut-off merging valve 5, bucket cut-off merging valve 6, straight travel valve 7, second boom cut-off merging valve 8, first boom control valve core 9, right travel control valve core 10, left travel control valve core 11, first dipper arm control valve core 12, second boom control valve core 13, bucket control valve core 14, second dipper arm control valve core 15, first boom first port relief valve 16, first boom second port relief valve 17, first dipper arm first port relief valve 18, first dipper arm second port relief valve 19, second boom first port relief valve 20, second boom second port relief valve 21, bucket first port relief valve Flow valve 22, bucket second port relief valve 23, second boom first port relief valve 24 and second boom second port relief valve 25, second boom load holding valve 26, second boom load holding valve 27, first boom load holding valve 28, first boom load holding valve 29, second boom first one-way valve 30, second boom second one-way valve 31, bucket first one-way valve 32, bucket second one-way valve 33, second boom first one-way valve 34, second boom second one-way valve 35, first boom first one-way valve 36, first boom second one-way valve 37; left travel one-way valve 38, right travel one-way valve 39, first boom first one-way valve 40, first boom second one-way valve 41, first process valve 42, second process valve 43. DETAILED DESCRIPTION

[0038] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. Technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may also include different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0040] In the description of the present invention, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0041] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0042] Example 1: Figure 1 As shown, this embodiment provides an electro-hydraulic control valve disc, which integrates a shut-off and merging valve 02 and a main control valve core 03. The valve disc is provided with an oil inlet P, a first working port A, a second working port B, an oil inlet and merging oil channel, and an oil return oil channel connected to an oil return port R;

[0043] The oil inlet of the cut-off merging valve 02 is connected to the oil inlet P, the first port of the cut-off merging valve 02 is respectively connected to the return oil channel and the return oil port of the main control valve core 03, the second port of the cut-off merging valve 02 is connected to the oil inlet of the main control valve core 03, and the third port of the cut-off merging valve 02 is connected to the oil inlet merging oil channel; the cut-off merging valve 02 includes at least a first working position, a second working position and a third working position. When the cut-off merging valve 02 is in the first working position (center position), the oil inlet of the cut-off merging valve 02 is connected to the first port (to achieve unloading); when the cut-off merging valve 02 is in the first working position (left position), the oil inlet of the cut-off merging valve 02 is connected to the second port; when the cut-off merging valve 02 is in the third working position (right position), the oil inlet of the cut-off merging valve 02 is connected to the third port (to achieve combined oil supply);

[0044] The main control valve core 03 is provided with an oil inlet, an oil return port, a first port and a second port. The oil inlet of the main control valve core 03 is also connected to the oil inlet merging oil channel, the oil return port of the main control valve core 03 is connected to the oil return oil channel, the first port of the main control valve core 03 is connected to the first working port A, and the second port of the main control valve core 03 is connected to the second working port B.

[0045] In this embodiment, Figure 1 As shown, the electro-hydraulic control valve disc further includes a first one-way valve 07 , and the oil inlet and oil merging passage supplies oil to the main control valve core 03 in a one-way manner through the first one-way valve 07 .

[0046] In this embodiment, Figure 1 As shown, the electro-hydraulic control valve disc further includes a main relief valve 01, which is disposed between the oil inlet P and the oil return passage. More specifically, the first port of the main relief valve 01 is connected to the oil inlet P, and the second port of the main relief valve 01 is connected to the oil return port R via the oil return passage.

[0047] In this embodiment, Figure 1 As shown, the electro-hydraulic control valve plate also includes a first port relief valve 05 and a second port relief valve 04. The first port relief valve 05 is arranged between the first working port A and the return oil channel, and the second port relief valve 04 is arranged between the second working port B and the return oil channel.

[0048] In this embodiment, Figure 1 As shown, the electro-hydraulic control valve disc further includes a load holding valve 06 , and the first port of the main control valve core 03 is connected to the first working port A through the load holding valve 06 .

[0049] In some embodiments, as Figure 1As shown, the main control valve core 03 includes at least a first working position, a second working position, and a third working position. When the main control valve core 03 is in the first working position (left position), the oil inlet of the main control valve core 03 is connected to the first port, and the second port of the main control valve core 03 is connected to the oil return port. When the main control valve core 03 is in the second working position (center position), the oil inlet, the first port, the second port, and the oil return port of the main control valve core 03 are disconnected. When the main control valve core 03 is in the third working position (right position), the oil inlet of the main control valve core 03 is connected to the second port, and the first port of the main control valve core 03 is connected to the oil return port. In this embodiment, the main control valve core 03 is a three-position, four-way valve.

[0050] In some embodiments, the electro-hydraulic control valve further includes a second one-way valve 08 , which is disposed between the oil inlet P and the oil inlet of the main control valve core 03 , and is used to supply oil to the main control valve core 03 in a one-way manner through the cut-off and merging valve 02 .

[0051] In this embodiment, Figure 1 As shown, the second one-way valve 08 is arranged between the second port of the cut-off and merging valve 02 and the oil inlet of the main control valve core 03.

[0052] In this application, the flow rate of the oil inlet P of the valve plate can be freely switched between unloading to the return oil channel (oil tank), independently supplying oil to the valve plate, and merging oil supply to other valve plates by cutting off the merging valve 02.

[0053] Example 2: Based on Example 1, the difference from Example 1 is that the second one-way valve 08 can also be arranged between the oil inlet and the second port of the cut-off and merging valve 02, that is, integrated into the cut-off and merging valve 02.

[0054] More specifically, Figure 2 As shown, in this embodiment, the cut-off merging valve 02 also includes a fourth working position, which is located between the first working position and the second working position. When the cut-off merging valve 02 is located in the fourth working position, the oil inlet of the cut-off merging valve 02 is unidirectionally connected to the second port through the second one-way valve 08.

[0055] Example 3: Based on Example 1, the difference from Example 1 is that the cut-off and merging valve 02 in this example is composed of a pressure cut-off valve 021 and a merging valve 022.

[0056] like Figure 3 As shown, an electro-hydraulic control valve disc is integrated with a cut-off and merging valve 02 and a main control valve core 03. The valve disc is provided with an oil inlet P, a first working port A, a second working port B, an oil inlet and merging oil channel, and an oil return oil channel connected to an oil return port R;

[0057] The shut-off and merging valve 02 consists of a pressure shut-off valve 021 and a merging valve 022. The oil inlets of the pressure shut-off valve 021 and the merging valve 022 are both connected to the oil inlet P. The outlet of the pressure shut-off valve 021 is connected to the oil return channel and the oil return port of the main control valve core 03, respectively. The first port of the merging valve 022 is connected to the oil inlet of the main control valve core 03, and the second port of the merging valve 02 is connected to the oil inlet and merging channel. When the pressure shut-off valve 021 is in the first working position (left position), the oil inlet and outlet of the pressure shut-off valve are not connected. When the pressure shut-off valve 021 is in the second working position (right position), the oil inlet and outlet of the pressure shut-off valve are connected.

[0058] When the merging valve 022 is located at the first working position (left position), the oil inlet of the merging valve 022 is connected to the first port; when the merging valve 022 is located at the second working position (right position), the oil inlet of the merging valve 022 is connected to the second port;

[0059] The main control valve core 03 is provided with an oil inlet, an oil return port, a first port and a second port. The oil inlet of the main control valve core 03 is also connected to the oil inlet merging oil channel, the oil return port of the main control valve core 03 is connected to the oil return oil channel, the first port of the main control valve core 03 is connected to the first working port A, and the second port of the main control valve core 03 is connected to the second working port B.

[0060] In some embodiments, the electro-hydraulic control valve disc further includes a first one-way valve 07 , and the oil inlet and oil merging passage supplies oil to the main control valve core 03 in a one-way manner through the first one-way valve 07 .

[0061] In some embodiments, the electro-hydraulic control valve plate also includes a main overflow valve 01, which is arranged between the oil inlet P and the return oil channel. Specifically, the first port of the main overflow valve 01 is connected to the oil inlet P, and the second port of the main overflow valve 01 is connected to the return oil port R through the return oil channel.

[0062] In some embodiments, the electro-hydraulic control valve plate also includes a first port overflow valve 05 and a second port overflow valve 04. The first port overflow valve 05 is arranged between the first working port A and the return oil channel, and the second port overflow valve 04 is arranged between the second working port B and the return oil channel.

[0063] In some embodiments, the electro-hydraulic control valve disc further includes a load holding valve 06 , and the first port of the main control valve core 03 is connected to the first working port A through the load holding valve 06 .

[0064] In some embodiments, the main control valve core 03 includes at least a first working position, a second working position and a third working position. When the main control valve core 03 is located in the left position of the first working position, the oil inlet of the main control valve core 03 is connected to the first port, and the second port of the main control valve core 03 is connected to the oil return port; when the main control valve core 03 is located in the middle position of the second working position, the oil inlet, the first port, the second port and the oil return port of the main control valve core 03 are not connected; when the main control valve core 03 is located in the right position of the third working position, the oil inlet of the main control valve core 03 is connected to the second port, and the first port of the main control valve core 03 is connected to the oil return port; in this embodiment, the main control valve core 03 is a three-position four-way valve.

[0065] In some embodiments, the electro-hydraulic control valve plate also includes a second one-way valve 08, which is arranged between the oil inlet P and the oil inlet of the main control valve core 03, and is used to supply oil to the main control valve core 03 in one direction through the cut-off and merging valve 02.

[0066] In this embodiment, Figure 3 As shown, the second one-way valve 08 is arranged between the first port of the merging valve 022 and the oil inlet of the main control valve core 03.

[0067] It should be noted that in the electro-hydraulic control valve plate of the present application, the positions of the plug-ins such as the port overflow valve and the load holding valve can be changed, or the number of corresponding plug-ins can be increased or decreased; at least one of the following control methods can be added to both ends of the electro-hydraulic control valve plate: hydraulic control, electric control, electro-hydraulic control, and CAN bus control.

[0068] Example 4: Based on Examples 1 to 3, this example also provides an electro-hydraulic control valve for a multi-pump system, comprising a plurality of working links, wherein the working links adopt the electro-hydraulic control valve plates described in any one of Examples 1 to 3, the return oil channels of the plurality of working links are interconnected and share a common return oil port, and the oil inlet and merging oil channels of the plurality of working links are directly or indirectly interconnected.

[0069] In some embodiments, a two-way electro-hydraulic control valve is provided. The two-way electro-hydraulic control valve is commonly used in the hydraulic system of a loader, mainly controlling the lifting and lowering of the loader's boom and the inward and outward swing of the bucket. The schematic diagram of the principle is shown in FIG. Figure 4In this embodiment, the multiple working links of the two-link electro-hydraulic control valve include a bucket link and a boom link, wherein the bucket link is provided with an oil inlet P1, an oil return port R, a first working port A1, and a second working port B1; the bucket link valve plate integrates a bucket link main relief valve 101, a bucket link cut-off and combining valve 102, a bucket link main control valve core 103, a bucket link first port relief valve 104, a bucket link second port relief valve 105, a bucket link first check valve 107, and a bucket link second check valve 108; the boom link is provided with an oil inlet P2, The first working port A2, the second working port B2, the boom connection valve plate integrates the boom connection main overflow valve 201, the boom connection cut-off combining valve 202, the boom connection main control valve core 203, the boom first port overflow valve 204 and the boom second port overflow valve 205, the boom load holding valve 206, the boom first check valve 207 and the boom second check valve 208; the first working port and the second working port of the bucket connection are used to connect with the bucket cylinder, and the first working port and the second working port of the boom connection are used to connect with the boom cylinder.

[0070] The working process of the two-way electro-hydraulic control valve is as follows:

[0071] When the boom moves alone, the boom joint shut-off merging valve 202 is controlled to open to the left position (the second working position), and the boom joint oil inlet P2 supplies oil to the boom joint main control valve core 203 through the boom joint shut-off merging valve 202. At the same time, the bucket joint shut-off merging valve 102 is controlled to open to the right position (the third working position), and the bucket joint oil inlet P1 supplies oil to the boom joint flow through the boom joint shut-off merging valve 202 and the oil inlet merging oil channel to ensure the required boom speed.

[0072] When the bucket moves alone, the bucket joint cut-off merging valve 102 is controlled to open to the left position (the second working position), and the oil inlet of the bucket joint supplies oil to the main control valve core of the bucket joint through the bucket joint cut-off merging valve; at the same time, the boom joint cut-off merging valve 202 is controlled to open to the right position (the third working position), and the oil inlet of the boom joint supplies oil to the bucket joint through the boom joint cut-off merging valve and the oil inlet merging oil channel to ensure the bucket speed requirement;

[0073] When the boom and bucket are in combined motion, the bucket coupling cut-off merging valve 102 and the boom coupling cut-off merging valve 202 are both opened to the left position (the second working position). The oil inlet P1 of the bucket coupling supplies oil to the main control valve core of the bucket coupling through the bucket coupling cut-off merging valve 102, and the oil inlet P2 of the boom coupling supplies oil to the main control valve core of the boom coupling through the boom coupling cut-off merging valve 202. The oil sources of the bucket coupling and the boom coupling are independent of each other and there is no load coupling.

[0074] When in standby state, the bucket joint cut-off merging valve 102 and the boom joint cut-off merging valve 202 are both in the middle position (first working position), the oil inlet P1 of the bucket joint is unloaded through the bucket joint cut-off merging valve 102, and the oil inlet P2 of the boom joint is unloaded through the boom joint cut-off merging valve 202, reducing the main pump output pressure and reducing system energy loss.

[0075] In some embodiments, this embodiment provides a seven-link electro-hydraulic control valve, which is mainly used in the hydraulic system of an electric excavator to mainly control the boom, arm, bucket and walking movements of the excavator. The schematic diagram of its principle is shown as follows: Figure 5 In this embodiment, the multiple working links of the seven-link electro-hydraulic control valve include, in sequence, a first boom link, a right travel link, a left travel link, a first dipper arm link, a second boom link, a bucket link, and a second dipper arm link;

[0076] The first boom is equipped with an oil inlet P1 and an oil return port R1. The valve plate integrates the first boom main relief valve 1, the first boom cut-off and combining valve 4, the first boom control valve core 9, the first boom first port relief valve 16 and the first boom second port relief valve 17, the first boom load holding valve 29, the first boom first check valve 40 and the first boom second check valve 41;

[0077] The valve plate of the right travel link integrates the first process valve 42, the right travel control valve core 10 and the right travel check valve 39;

[0078] The valve plate of the left travel link integrates the linear travel valve 7, the left travel control valve core 11 and the left travel check valve 38, which are used to control the linear travel of the excavator;

[0079] The first boom is connected with an oil inlet P2, and the valve plate integrates the first boom main relief valve 2, the first boom cut-off and combining valve 5, the first boom control valve core 12, the first boom first port relief valve 18 and the first boom second port relief valve 19, the first boom load holding valve 28, the first boom first check valve 36 and the first boom second check valve 37;

[0080] The second boom link, the valve plate integrates the second boom cut-off and combining valve 8, the second boom control valve core 13, the second boom first port relief valve 20 and the second boom second port relief valve 21, the second boom load holding valve 27, the second boom first check valve 34 and the second boom second check valve 35;

[0081] The bucket is connected with an oil inlet P3, and the valve plate integrates the bucket main relief valve 3, the bucket cut-off and combining valve 6, the bucket control valve core 14, the bucket first port relief valve 22 and the bucket second port relief valve 23, the bucket first check valve 32 and the bucket second check valve 33;

[0082] The valve plate of the second boom link integrates the second process valve 43, the second boom control valve core 15, the second boom first port relief valve 24 and the second boom second port relief valve 25, the second boom load holding valve 26, the second boom first check valve 30 and the second boom second check valve 31. In this embodiment, the second process valve 43 is always in the first working position (neutral position).

[0083] The oil return passages of the first boom link, the right traveling link, the left traveling link, the first dipper link, the second boom link, the bucket link, and the second dipper link are all connected to the oil return port R1 of the first boom link. The oil inlet merging passages of the first boom link and the right traveling link are connected, the oil inlet merging passages of the left traveling link and the first dipper link are connected, and the oil inlet merging passages of the second boom link, the bucket link, and the second dipper link are connected;

[0084] The oil outlet of the first process valve 42 is connected to the oil inlet of the right travel control valve core 10 for supplying oil to the right travel control valve core 10;

[0085] The first port of the linear travel valve 7 is connected to the oil inlet of the left travel control valve core 11, and the second port is connected to the oil inlet merging oil channel of the left travel link; when the linear travel valve 7 is in the first working position (middle position), the oil inlet, the first port and the second port are not connected to each other; when the linear travel valve 7 is in the second working position (left position), the oil inlet and the first port are connected to supply oil to the left travel control valve core 11; when the linear travel valve 7 is in the third working position (right position), the oil inlet and the second port are connected, and the oil inlet of the first process valve 42, the linear travel valve 7 and the second boom cut-off merging valve 8 are connected.

[0086] The working process of the seven-link electro-hydraulic control valve is as follows:

[0087] When the boom moves alone, the first boom control valve core 9 and the second boom control valve core 13 are opened at the same time, the first boom cut-off merging valve 4 is opened to the second working position (left position), and the oil inlet P1 of the first boom connection is supplied to the first boom through the first boom cut-off merging valve 4 and the first boom second check valve 41, the bucket cut-off merging valve 6 is opened to the third working position (right position), and the oil inlet P3 of the bucket connection is supplied to the first boom through the third working position (right position) of the bucket cut-off merging valve 6 and the oil inlet merging oil passage. The first check valve 34 of the second boom supplies oil to the second boom. The oil inlet P2 of the first boom connection selects, according to the actual flow demand of the boom, to unload through the first boom cut-off and merging valve 5 in the first working position (middle position) or through the first boom cut-off and merging valve 5 in the third working position (right position), and then through the third working position (right position) of the linear travel valve 7 and the third working position (right position) of the second boom cut-off and merging valve 8 through the oil inlet merging oil channel to combine and supply oil to the second boom, ensuring that the boom movement speed requirement is met;

[0088] When the boom moves alone, the first boom control valve core 12 and the second boom control valve core 15 are opened at the same time, the first boom cut-off and merging valve 5 is opened to the second working position (left position), and the oil inlet P2 of the first boom link supplies oil to the first boom through the second working position (left position) of the first boom cut-off and merging valve 5 and the second one-way valve 37 of the first boom. The third working position (right position) of the bucket cut-off and merging valve 6 is opened, and the oil inlet P3 of the bucket link supplies oil to the second boom through the third working position (right position) of the bucket cut-off and merging valve 6 and the oil inlet merging oil channel through the first one-way valve 30 of the second boom. The oil inlet P1 of the first boom link chooses to unload through the first working position (middle position) of the first boom cut-off and merging valve 4 or through the third working position (right position) of the first boom cut-off and merging valve 4 according to the actual flow demand of the boom, and supplies oil to the second boom through the right travel one-way valve 39 and the third working position (right position) of the second boom cut-off and merging valve 8, so as to ensure that the boom movement speed requirement is met;

[0089] When the bucket moves alone, the bucket control valve core 14 opens, the bucket cut-off and merging valve 6 opens to the second working position (left position), and the oil inlet P3 of the bucket link supplies oil to the bucket through the second working position (left position) of the bucket cut-off and merging valve 6 and the second bucket check valve 33. At the same time, the first boom cut-off and merging valve 4 opens to the third working position (right position), and the oil inlet P1 of the first boom link passes through the right travel check valve 39, the third working position (right position) of the second boom cut-off and merging valve 8 and the first bucket check valve 32 to combine and supply oil to the bucket, ensuring that the bucket movement speed requirement is met;

[0090] When the boom and arm are in combined motion, the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom control valve core 9, the oil inlet P2 of the first arm connection supplies oil to the arm through the first arm control valve core 12, and the oil inlet P3 of the bucket connection supplies oil to the arm through the second arm control valve core 15. The oil sources of the boom and arm are independent of each other and there is no load coupling.

[0091] When the arm and bucket are in combined motion, the oil inlet P2 of the first arm connection supplies oil to the arm through the first arm control valve core 12, and the oil inlet P3 of the bucket connection supplies oil to the bucket through the bucket control valve core 14. The oil inlet P1 of the first boom connection cuts off the third working position (right position) of the converging valve 4 of the first boom according to the demand of the arm, and then supplies oil to the arm through the third working position (right position) of the linear travel valve 7 and the first check valve 36 of the first boom. The oil sources of the arm and bucket are independent of each other and there is no load coupling.

[0092] When the boom and bucket are in combined motion, the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom control valve core 9, and the oil inlet P3 of the bucket connection supplies oil to the bucket through the bucket control valve 14. The oil inlet P2 of the first dipper arm connection is unloaded in the first working position (neutral position) through the first dipper arm cut-off combining valve 5. The oil sources of the boom and bucket are independent of each other and there is no load coupling.

[0093] When the boom, bucket and arm are in combined action, the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom control valve core 9, the oil inlet P2 of the first arm connection supplies oil to the arm through the first arm control valve core 12, and the oil inlet P3 of the bucket connection supplies oil to the bucket through the bucket control valve core 14. The oil sources of the boom, bucket and arm are independent of each other and there is no load coupling.

[0094] When the vehicle moves alone, the first boom cut-off merging valve 4 and the first arm cut-off merging valve 5 are both opened to the third working position (right position), and the oil inlet P1 of the first boom connection is supplied to the right travel through the third working position (right position) of the first boom cut-off merging valve 4 and the oil inlet merging oil channel through the right travel check valve 39, and the oil inlet P2 of the first arm connection is supplied to the left travel through the third working position (right position) of the first arm cut-off merging valve 5 and the oil inlet merging oil channel through the left travel check valve 38. The oil inlet P1 of the first boom connection and the oil inlet P2 of the first arm connection are dual-pumped for travel to ensure travel speed; when traveling in a straight line, the straight line travel valve 7 is opened to the second working position (left position), and after the oil inlet P1 of the first boom connection is connected with the oil inlet P2 of the first arm connection, oil is supplied to both left and right travels at the same time to ensure that the excavator travels in a straight line;

[0095] When getting on and off the vehicle, the bucket cut-off merging valve 6 is opened to the third working position (right position), and the oil inlet P3 of the bucket link supplies oil to the second boom, the second dipper arm and the bucket through the oil inlet merging oil channel to ensure that the corresponding actions required for getting on the vehicle are completed.

[0096] In summary, in the present application, (1) a valve plate structure of an electro-hydraulic control valve for multiple pumps is adopted, which can realize the free switching of independent oil source control of each actuator and the combined oil supply state of multiple pumps according to the actual working conditions, solve the energy waste problem caused by the combined action load coupling of multiple actuators of the traditional multi-way valve, and increase the control freedom; (2) the plate-type multi-way valve composed of the electro-hydraulic control valve designed by the present invention can realize the combined oil supply of multiple pumps when a single actuator is in action, meet the single action speed requirement, and reduce the output power of a single pump at the same time. Each valve plate is modularly designed independently, and the casting blanks used are the same, and the traditional plate-type multi-way valve oil inlet connection is eliminated, with a simple structure and low manufacturing cost; (3) The plate-type multi-way valve composed of the electro-hydraulic control valve designed by the present invention can realize independent oil source supply when multiple actuators act in combination, and the loads of each actuator are independent of each other, and both can realize pump control adjustment, avoid coupling energy loss, and facilitate the realization of pump-valve integrated design; (4) The plate-type multi-way valve composed of the electro-hydraulic control valve designed by the present invention can change the cut-off confluence valve core into a straight-line travel valve core when the valve plate is used as a travel link, ensuring that the host can achieve The straight-line travel function is realized, and the valve plate does not need to be separately designed with a straight-line travel circuit, which can simplify the main valve structure and reduce manufacturing costs; (5) The plate-type multi-way valve composed of the electro-hydraulic control valve designed by the present invention can change the cut-off merging valve core to the merging valve core when the valve plate needs to cross the circuit to merge the oil supply, ensuring that the main valve can achieve cross-circuit merging and meet the flow requirements of the corresponding actuators. At the same time, the valve plate does not need to be separately designed with a cross-circuit merging circuit, which can simplify the main valve structure and reduce manufacturing costs; (6) The main valve can be designed with a CAN bus end cover, and the control method adopts CAN bus control, electro-hydraulic composite control and other control methods.

[0097] Example 5: This example provides a hydraulic system for engineering machinery, which is equipped with any electro-hydraulic control valve described in Example 4.

[0098] In some embodiments, a loader hydraulic system is configured with the above-mentioned two-way electro-hydraulic control valve.

[0099] In some embodiments, an excavator hydraulic system is configured with the above-mentioned seven-connection electro-hydraulic control valve.

[0100] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An electro-hydraulic control valve disc, characterized in that: A shut-off merging valve (02) and a main control valve core (03) are integrated, and the valve plate is provided with an oil inlet P, a first working port A, a second working port B, an oil inlet merging oil channel, and an oil return oil channel connected to an oil return port R; The oil inlet of the cut-off merging valve (02) is connected to the oil inlet P, the first port of the cut-off merging valve (02) is respectively connected to the oil return oil channel and the oil return port of the main control valve core (03), the second port of the cut-off merging valve (02) is connected to the oil inlet of the main control valve core (03), and the third port of the cut-off merging valve (02) is connected to the oil inlet merging oil channel; the cut-off merging valve (02) includes at least a first working position, a second working position and a third working position, when the cut-off merging valve (02) is in the first working position, the oil inlet of the cut-off merging valve (02) is connected to the first port; when the cut-off merging valve (02) is in the second working position, the oil inlet of the cut-off merging valve (02) is connected to the second port; when the cut-off merging valve (02) is in the third working position, the oil inlet of the cut-off merging valve (02) is connected to the third port; The main control valve core (03) is provided with an oil inlet, an oil return port, a first port, and a second port. The oil inlet of the main control valve core (03) is also connected to the oil inlet merging oil channel, the oil return port of the main control valve core (03) is connected to the oil return oil channel, the first port of the main control valve core (03) is connected to the first working port A, and the second port of the main control valve core (03) is connected to the second working port B.

2. An electro-hydraulic control valve disc, characterized in that: A shut-off merging valve (02) and a main control valve core (03) are integrated, and the valve plate is provided with an oil inlet P, a first working port A, a second working port B, an oil inlet merging oil channel, and an oil return oil channel connected to an oil return port R; The cut-off and merging valve (02) is composed of a pressure cut-off valve (021) and a merging valve (022). The oil inlets of the pressure cut-off valve (021) and the merging valve (022) are both connected to the oil inlet P. The outlet of the pressure cut-off valve (021) is respectively connected to the oil return channel and the oil return port of the main control valve core (03). The first port of the merging valve (022) is connected to the oil inlet of the main control valve core (03), and the second port of the merging valve (02) is connected to the oil inlet and merging channel. When the pressure cut-off valve (021) is located in the first working position, the oil inlet and outlet of the pressure cut-off valve are not connected. When the pressure cut-off valve (021) is located in the second working position, the oil inlet and outlet of the pressure cut-off valve are connected. When the merging valve (022) is located in the first working position, the oil inlet of the merging valve (022) is connected to the first port; when the merging valve (022) is located in the second working position, the oil inlet of the merging valve (022) is connected to the second port; The main control valve core (03) is provided with an oil inlet, an oil return port, a first port, and a second port. The oil inlet of the main control valve core (03) is also connected to the oil inlet merging oil channel, the oil return port of the main control valve core (03) is connected to the oil return oil channel, the first port of the main control valve core (03) is connected to the first working port A, and the second port of the main control valve core (03) is connected to the second working port B.

3. The electro-hydraulic control valve disc according to claim 1 or 2, characterized in that: It also includes a first one-way valve (07), and the oil inlet and oil merging passage supplies oil to the main control valve core (03) in a one-way manner through the first one-way valve (07).

4. The electro-hydraulic control valve disc according to claim 1 or 2, characterized in that: It also includes a main overflow valve (01), which is arranged between the oil inlet P and the oil return channel.

5. The electro-hydraulic control valve disc according to claim 1 or 2, characterized in that: It also includes a first port relief valve (05) and a second port relief valve (04), wherein the first port relief valve (05) is provided between the first working port A and the oil return passage, and the second port relief valve (04) is provided between the second working port B and the oil return passage.

6. The electro-hydraulic control valve disc according to claim 1 or 2, characterized in that: It also includes a load holding valve (06), and the first port of the main control valve core (03) is connected to the first working port A through the load holding valve (06).

7. The electro-hydraulic control valve disc according to claim 1 or 2, characterized in that: It also includes a second one-way valve (08), which is arranged between the oil inlet P and the oil inlet of the main control valve core (03) and is used to supply oil to the main control valve core (03) in a one-way manner through the cut-off and merging valve (02).

8. An electro-hydraulic control valve, characterized in that: It comprises a plurality of working links, wherein the working links adopt the electro-hydraulic control valve plate according to any one of claims 1 to 7, the oil return channels of the plurality of working links are connected and share a return oil port, and the oil inlet and merging oil channels of the plurality of working links are directly or indirectly connected.

9. The electro-hydraulic control valve according to claim 8, characterized in that: The multiple working links include a bucket link and a boom link, wherein the first working port and the second working port of the bucket link are used to connect to the bucket oil cylinder, and the first working port and the second working port of the boom link are used to connect to the boom oil cylinder; the oil inlet merging oil passages of the bucket link and the boom link are connected; When the boom moves alone, the boom joint cut-off merging valve is controlled to open to the second working position, and the boom joint oil inlet supplies oil to the boom joint main control valve core through the boom joint cut-off merging valve; at the same time, the bucket joint cut-off merging valve is controlled to open to the third working position, and the bucket joint oil inlet supplies oil to the boom joint flow through the boom joint cut-off merging valve and the oil inlet merging oil channel to ensure the boom speed requirement; When the bucket moves alone, the bucket joint cut-off merging valve is controlled to open to the second working position, and the oil inlet of the bucket joint supplies oil to the main control valve core of the bucket joint through the bucket joint cut-off merging valve; at the same time, the boom joint cut-off merging valve is controlled to open to the third working position, and the oil inlet of the boom joint supplies oil to the bucket joint through the boom joint cut-off merging valve and the oil inlet merging oil channel to ensure the bucket speed requirement; When the boom and bucket are in combined motion, the bucket joint cut-off merging valve and the boom joint cut-off merging valve are both controlled to open to the second working position. The oil inlet of the bucket joint supplies oil to the main control valve core of the bucket joint through the bucket joint cut-off merging valve, and the oil inlet of the boom joint supplies oil to the main control valve core of the boom joint through the boom joint cut-off merging valve. The oil sources of the bucket joint and the boom joint are independent of each other and there is no load coupling. When in standby state, the bucket joint cut-off merging valve and the boom joint cut-off merging valve are both in the first working position, the oil inlet of the bucket joint is unloaded through the bucket joint cut-off merging valve, and the oil inlet of the boom joint is unloaded through the boom joint cut-off merging valve, reducing the output pressure of the main pump and reducing system energy loss.

10. The electro-hydraulic control valve according to claim 8, characterized in that: The plurality of working links include, in sequence, a first boom link, a right traveling link, a left traveling link, a first dipper arm link, a second boom link, a bucket link, and a second dipper arm link; The first boom is provided with an oil inlet P1 and an oil return port R1, and the valve plate integrates a first boom cut-off and converging valve (4), a first boom control valve core (9), and a first boom first check valve (40); The valve plate of the right travel link integrates a first process valve (42), a right travel control valve core (10) and a right travel check valve (39); The valve plate of the left travel link integrates a linear travel valve (7), a left travel control valve core (11) and a left travel check valve (38); The first boom is connected to an oil inlet P2, and the valve plate integrates a first boom cut-off and merging valve (5), a first boom control valve core (12), and a first boom first check valve (36); A second boom link, wherein the valve plate integrates a second boom cut-off and confluence valve (8), a second boom control valve core (13), and a second boom first check valve (34); The bucket is provided with an oil inlet P3, and the valve plate integrates a bucket cut-off and converging valve (6), a bucket control valve core (14), and a bucket first one-way valve (32); The valve plate of the second boom link integrates a second process valve (43), a second boom control valve core (15), and a second boom first one-way valve (30); the second process valve (43) is always located in the first working position; The return oil passages of the first boom link, the right traveling link, the left traveling link, the first dipper link, the second boom link, the bucket link and the second dipper link are all connected to the return oil port R1 of the first boom link. The oil inlet merging oil passages of the first boom link and the right traveling link are connected, the oil inlet merging oil passages of the left traveling link and the first dipper link are connected, and the oil inlet merging oil passages of the second boom link, the bucket link and the second dipper link are connected. The oil outlet of the first process valve (42) is connected to the oil inlet of the right travel control valve core (10) for supplying oil to the right travel control valve core (10); The first port of the linear travel valve (7) is connected to the oil inlet of the left travel control valve core (11), and the second port is connected to the oil inlet merging oil channel of the left travel link; when the linear travel valve (7) is in the first working position, the oil inlet, the first port and the second port are not connected to each other; when the linear travel valve (7) is in the second working position, the oil inlet is connected to the first port to supply oil to the left travel control valve core (11); when the linear travel valve (7) is in the third working position, the oil inlet is connected to the second port, and the oil inlets of the first process valve (42), the linear travel valve (7) and the second boom cut-off merging valve (8) are connected.

11. The control method of the electro-hydraulic control valve according to claim 10, characterized in that: include: When the boom moves alone, the first boom control valve core (9) and the second boom control valve core (13) are opened at the same time, the first boom cut-off merging valve (4) is opened to the second working position, the oil inlet P1 of the first boom connection is supplied to the first boom through the first boom cut-off merging valve (4), the bucket cut-off merging valve (6) is opened to the third working position, the oil inlet P3 of the bucket connection is supplied to the second boom through the bucket cut-off merging valve (6) and the oil inlet merging oil channel through the first check valve (34) of the second boom, and the oil inlet P2 of the first dipper arm connection is selected according to the actual flow demand of the boom to unload through the first dipper arm cut-off merging valve (5) in the first working position or through the first dipper arm cut-off merging valve (5) in the third working position, and to merge and supply oil to the second boom through the oil inlet merging oil channel through the linear travel valve (7) in the third working position and the second boom cut-off merging valve (8) in the third working position, so as to ensure that the boom movement speed requirement is met; And / or, when the boom moves alone, the first boom control valve core (12) and the second boom control valve core (15) are opened simultaneously, the first boom cut-off merging valve (5) is opened to the second working position, the oil inlet P2 of the first boom link supplies oil to the first boom through the first boom cut-off merging valve (5), the bucket cut-off merging valve (6) is opened to the third working position, the oil inlet P3 of the bucket link supplies oil to the second boom through the bucket cut-off merging valve (6) and the oil inlet merging oil channel through the second boom first check valve (30), and the oil inlet P1 of the first boom link selects to unload through the first boom cut-off merging valve (4) first working position or through the first boom cut-off merging valve (4) third working position, and supplies oil to the second boom through the right travel check valve (39) and the second boom cut-off merging valve (8) third working position according to the actual flow demand of the boom, so as to ensure that the boom movement speed requirement is met; And / or, when the bucket moves alone, the bucket control valve core (14) is opened, the bucket cut-off merging valve (6) is opened to the second working position, the oil inlet P3 of the bucket link is supplied to the bucket through the bucket cut-off merging valve (6), and at the same time, the first boom cut-off merging valve (4) is opened to the third working position, and the oil inlet P1 of the first boom link is supplied to the bucket through the right travel check valve (39), the second boom cut-off merging valve (8) to the third working position and the bucket first check valve (32), so as to ensure that the bucket movement speed requirement is met; And / or, when the boom and the dipper arm are in combined motion, the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom control valve core (9), the oil inlet P2 of the first dipper arm connection supplies oil to the dipper arm through the first dipper arm control valve core (12), and the oil inlet P3 of the bucket connection supplies oil to the dipper arm through the second dipper arm control valve core (15), and the oil sources of the boom and the dipper arm are independent of each other and are not coupled with load; And / or, when the boom and bucket are in combined motion, the oil inlet P2 of the first boom connection supplies oil to the boom through the first boom control valve core (12), the oil inlet P3 of the bucket connection supplies oil to the bucket through the bucket control valve core (14), and the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom cut-off merging valve (4) in the third working position, through the linear travel valve (7) in the third working position and the first one-way valve (36) of the first boom connection according to the boom demand, and the boom and bucket oil sources are independent of each other and are not load-coupled; And / or, when the boom and bucket are in combined motion, the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom control valve core (9), the oil inlet P3 of the bucket connection supplies oil to the bucket through the bucket control valve core (14), and the oil inlet P2 of the first dipper arm connection is unloaded at the first working position through the first dipper arm cut-off merging valve (5), and the oil sources of the boom and bucket are independent of each other and are not coupled with load; And / or, when the boom, bucket and stick are in a combined action, the oil inlet P1 of the first boom connection supplies oil to the boom through the first boom control valve core (9), the oil inlet P2 of the first stick connection supplies oil to the stick through the first stick control valve core (12), and the oil inlet P3 of the bucket connection supplies oil to the bucket through the bucket control valve core (14), and the oil sources of the boom, bucket and stick are independent of each other and are not load-coupled; And / or, when the vehicle is dismounted and walking alone, the first boom cut-off merging valve (4) and the first dipper arm cut-off merging valve (5) are both opened to the third working position, the oil inlet P1 of the first boom connection is supplied to the right side of the vehicle through the first boom cut-off merging valve (4) and the oil inlet merging oil channel through the right travel check valve (39), and the oil inlet P2 of the first dipper arm connection is supplied to the left side of the vehicle through the first dipper arm cut-off merging valve (5) and the oil inlet merging oil channel through the left travel check valve (38), and the oil inlet P1 of the first boom connection and the oil inlet P2 of the first dipper arm connection are dual-pumped for walking to ensure the walking speed; when walking in a straight line, the straight line travel valve (7) is opened to the second working position, and the oil inlet P1 of the first boom connection and the oil inlet P2 of the first dipper arm connection are connected, and then the oil is supplied to the left and right sides of the vehicle at the same time to ensure the straight line walking of the excavator; And / or, when the vehicle is loaded and unloaded, the bucket cut-off merging valve (6) is opened to the third working position, and the oil inlet P3 of the bucket joint is supplied with oil to the second boom, the second dipper arm and the bucket through the oil inlet merging oil channel, thereby ensuring that the corresponding actions required for loading and unloading are completed.

12. A hydraulic system for engineering machinery, characterized in that: Equipped with the electro-hydraulic control valve according to any one of claims 8 to 10.

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