Constant variable dual pump composite control valve and hydraulic system

Abstract

The application discloses a constant variable double-pump composite control valve and a hydraulic system, a main valve body is provided with a P1 port connected with a variable pump and a P2 port connected with a constant pump, the P1 port and the P2 port are both oil inlet ports, the main valve body is provided with an oil inlet oil channel, the oil inlet oil channel comprises a first oil inlet channel communicated with the P1 port and a second oil inlet channel communicated with the P2 port, a confluence valve is arranged on one side of the main valve body close to the P2 port, and the confluence valve is communicated with the second oil inlet channel. The flow access of the constant pump to the main valve body is controlled through the confluence valve, when the required flow of the system is greater than the flow provided by the variable pump, the valve core of the confluence valve is moved to make the second oil inlet channel communicated with the P2 port to form a passage, the constant pump pumps hydraulic oil into the second oil inlet channel to supplement the required flow, and the flow supplement is not required to be separately controlled by additionally arranging a valve body and an oil channel, the double-pump confluence is realized in a smaller space, and the flow supplement through the constant pump avoids the insufficient flow supply caused by the limited displacement of the variable pump due to the power limitation of the engine.

Description

Technical Field

[0001] This application belongs to the field of hydraulic technology, specifically relating to a constant-variable dual-pump composite control valve and hydraulic system. Background Technology

[0002] Variable displacement piston pumps are crucial components in hydraulic systems. They achieve oil suction and pressure by changing the volume of the sealed working chamber through the reciprocating motion of the piston within the cylinder. Piston pumps are characterized by high rated pressure, compact structure, high efficiency, and convenient flow rate adjustment. In contrast, a fixed displacement pump discharges a constant volume of oil per revolution of its shaft. Currently, mid-range loaders are equipped with a dual-pump system consisting of a variable displacement piston pump and a fixed displacement gear pump. However, the power limitations imposed by off-road machinery on the engine affect the displacement of the main hydraulic pump, thus limiting its capacity and potentially leading to a decline in the performance of the main engine.

[0003] Furthermore, the hydraulic control valve currently used in constant-variable systems is a combination of three control valves: an open-heart main valve, a confluence logic valve, and a shuttle valve. This combination is costly, and installing these three control valves requires a large amount of space. Utility Model Content

[0004] This application provides a constant-variable dual-pump composite control valve and hydraulic system, which solves the problems of large installation space and high cost required for hydraulic systems with multiple valve bodies, and avoids the problem of insufficient oil supply caused by the limitation of the main pump displacement due to engine power limitation.

[0005] The technical solution adopted in this application is as follows:

[0006] A constant-variable dual-pump composite control valve includes a main valve body, which is connected to an oil tank and an oil cylinder via pipelines. The main valve body has a P1 port connected to a variable pump and a P2 port connected to a fixed-displacement pump. Both the P1 port and the P2 port are oil inlets. The main valve body has an oil inlet passage, which includes a first oil inlet passage communicating with the P1 port and a second oil inlet passage communicating with the P2 port. A merging valve is provided on the side of the main valve body near the P2 port, and the merging valve communicates with the second oil inlet passage.

[0007] The first oil inlet and the second oil inlet are arranged side by side along the first direction. The main valve body is also provided with an oil outlet along the second direction. The end of the oil outlet is provided with an oil outlet. The oil outlet is connected to the oil cylinder through a pipeline. The first direction and the second direction are at an angle.

[0008] The main valve body is provided with a directional valve connecting the oil inlet passage and the oil outlet passage. The directional valve is located between the oil inlet passage and the oil outlet passage to connect or disconnect the oil inlet passage and the oil outlet passage.

[0009] The steering valve includes a bucket slide valve and a boom slide valve arranged in parallel. The oil outlet passage includes a first oil outlet passage and a second oil outlet passage located on both sides of the bucket slide valve, and a third oil outlet passage and a fourth oil outlet passage located on both sides of the boom slide valve. Each of the oil outlet passages is provided with an oil outlet.

[0010] The main valve body is provided with a port overflow valve connected to the oil outlet passage. There are two port overflow valves, which are located in the first oil outlet passage and the second oil outlet passage, respectively.

[0011] The main valve body is equipped with an LS safety valve, which is located on the same side of the confluence valve and is connected to the first oil inlet passage.

[0012] The main valve body is provided with a main relief valve, which is located on the opposite side of the confluence valve and is connected to the second oil inlet passage.

[0013] The main valve body is equipped with a pressure compensator, which is connected to the oil inlet passage.

[0014] The main valve body is also provided with an oil return port connected to the oil tank and an oil return passage located in the main valve body and connected to the oil return port. A back pressure valve is provided between the oil return passage and the oil return port.

[0015] A hydraulic system is provided in a loader, and the hydraulic system is provided with a composite control valve as described in any of the preceding claims.

[0016] Due to the adoption of the above technical solution, the beneficial effects achieved by this application are as follows:

[0017] This application's solution connects a fixed-displacement pump and a variable-displacement pump to the main valve body via two inlets. A confluence valve controls the flow from the fixed-displacement pump into the main valve body. Both the fixed-displacement and variable-displacement pumps supply hydraulic oil to the cylinders through this main valve body. In standby mode, the variable-displacement pump has its minimum tilt angle and provides almost no flow. The fixed-displacement pump is unloaded through the confluence valve. When the loader is operating, the variable-displacement pump provides flow first, and the fixed-displacement pump does not provide flow due to the confluence valve's limitation. When the required flow exceeds the flow provided by the variable-displacement pump, the confluence valve's spool moves, connecting the second inlet to port P2, forming a passage. The fixed-displacement pump then pumps hydraulic oil into the second inlet to supplement the required flow. This eliminates the need for a separate valve body and oil circuit for flow supplementation, resulting in a more compact overall structure. The dual-pump confluence of the fixed-displacement and variable-displacement pumps is achieved within a smaller space through the main valve body. Furthermore, the flow supplementation by the fixed-displacement pump avoids the problem of insufficient flow supply caused by engine power limitations restricting the variable-displacement pump's displacement. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0019] Figure 1 This is a perspective view of the composite control valve in one embodiment of the present invention;

[0020] Figure 2 This is a cross-sectional schematic diagram of the interior of the main valve body in one embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of a confluence valve in one embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the first oil inlet passage in one embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the second oil inlet passage in one embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the first oil outlet and the second oil outlet in one embodiment of the present invention;

[0025] Figure 7 This is a schematic diagram of the third and fourth oil outlet channels in one embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of the steering valve and back pressure valve in one embodiment of the present invention;

[0027] Figure 9 This is a schematic diagram of the main relief valve in one embodiment of the present invention;

[0028] Figure 10 This is a schematic diagram of the LS safety valve in one embodiment of the present invention;

[0029] Figure 11 This is a schematic diagram showing the position of the pressure compensator in one embodiment of the present invention;

[0030] Figure 12 This is a schematic diagram of another position of the pressure compensator in one embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Main valve body; 100-P1 port; 200-P2 port; 300-First oil inlet channel; 400-Second oil inlet channel; 500-First oil outlet channel; 510-A1 oil outlet; 600-Second oil outlet channel; 610-B1 oil outlet; 700-Third oil outlet channel; 710-A2 oil outlet; 800-Fourth oil outlet channel; 810-B2 oil outlet; 900-Return oil channel; 910-Return oil port;

[0033] 2-Combination valve, 3-Bucket slide valve, 4-Boom slide valve, 5-Port relief valve, 6-LS safety valve, 7-Main relief valve, 8-Pressure compensator, 9-Back pressure valve. Detailed Implementation

[0034] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0035] Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below. It should be noted that, unless otherwise specified, the embodiments of this application and the features thereof can be combined with each other.

[0036] Furthermore, it should be understood in the description of this application that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0039] This application provides a constant-variable dual-pump composite control valve, such as... Figures 1 to 12 As shown, the main valve body 1 is connected to the oil tank and the oil cylinder respectively through pipelines. The main valve body 1 is provided with a P1 port 100 connected to the variable pump and a P2 port 200 connected to the fixed pump. Both the P1 port 100 and the P2 port 200 are oil inlets. The main valve body 1 is provided with an oil inlet passage, which includes a first oil inlet passage 300 connected to the P1 port 100 and a second oil inlet passage 400 connected to the P2 port 200. A confluence valve 2 is provided on the side of the main valve body 1 near the P2 port 200, and the confluence valve 2 is connected to the second oil inlet passage 400.

[0040] This application solution connects a fixed displacement pump and a variable displacement pump to the main valve body 1 via two inlets. A confluence valve 2 controls the flow from the fixed displacement pump into the main valve body 1. Both the fixed displacement pump and the variable displacement pump supply hydraulic oil to the cylinders through the main valve body 1. In standby mode, the variable displacement pump has its minimum swing angle and provides almost no flow. The fixed displacement pump is unloaded through the confluence valve 2. When the loader is working, the variable displacement pump provides flow first. Under the constraint of the confluence valve 2, the fixed displacement pump does not provide flow. When the required flow exceeds the flow provided by the variable displacement pump, the valve core of the confluence valve 2 moves, connecting the second inlet 400 to port P2 200, forming a passage. The fixed displacement pump then pumps hydraulic oil into the second inlet 400 to supplement the required flow. This eliminates the need for separate valve bodies and oil circuits for flow supplementation, resulting in a more compact overall structure. The dual-pump confluence of the fixed displacement pump and the variable displacement pump is achieved within a smaller space through the main valve body 1. Furthermore, the flow supplementation by the fixed displacement pump avoids the problem of insufficient flow supply caused by engine power limitations restricting the displacement of the variable displacement pump.

[0041] Integrating the confluence pump into the main valve body 1 and positioning it near the P2 port 200, close to the fixed displacement pump, facilitates the rapid response and distribution of the flow provided by the fixed displacement pump to the confluence valve 2, further improving the working efficiency of the composite control valve. Furthermore, this design separates the oil passages for the fixed displacement pump and the variable displacement pump at the inlet, allowing for a more rational internal layout of the valve body within a compact space and avoiding flow channel confusion.

[0042] Furthermore, such as Figures 2 to 4 As shown, the first oil inlet channel 300 and the second oil inlet channel 400 are arranged side by side along the first direction. The main valve body 1 is also provided with an oil outlet channel arranged along the second direction. The end of the oil outlet channel is provided with an oil outlet, and the oil outlet is connected to the oil cylinder through a pipeline. The first direction and the second direction are at an angle.

[0043] It should be noted that, since the main valve body 1 has a three-dimensional structure, the oil inlet and the oil outlet are located on different planes of the main valve body 1. The oil inlet channel connected to the oil inlet and the oil outlet channel connected to the oil outlet naturally form an angle. After the variable pump or fixed pump pumps in the flow through the oil inlet, the hydraulic oil flows along the oil inlet channel. When it flows to the intersection of the oil inlet channel and the oil outlet channel, it enters the oil outlet channel and continues to flow along the oil outlet channel to the oil outlet.

[0044] It is understandable that the inner cavity of the main valve body 1 is provided with a confluence channel for the first oil passage and the second oil passage. When it is necessary to supplement the flow through the metering pump, both the first oil passage and the second oil passage are in the process of forming a passage. The fluid in the second oil passage and the fluid in the first oil passage merge in the inner cavity of the main valve body 1 to supply oil together, and flow from the oil outlet to the oil cylinder.

[0045] Furthermore, the main valve body 1 is provided with a directional valve that connects the inlet oil passage and the outlet oil passage. The directional valve is located between the inlet oil passage and the outlet oil passage so that the inlet oil passage and the outlet oil passage can be connected or disconnected.

[0046] The flow of hydraulic oil is redirected from the inlet oil passage to the outlet oil passage by a directional valve, thereby achieving the distribution of hydraulic oil flow.

[0047] Furthermore, such as Figure 1 as well as Figures 6 to 8 As shown, the steering valve includes a bucket slide valve 3 and a boom slide valve 4 arranged in parallel. The oil outlet channels include a first oil outlet channel 500 and a second oil outlet channel 600 located on both sides of the bucket slide valve 3, and a third oil outlet channel 700 and a fourth oil outlet channel 800 located on both sides of the boom slide valve 4. Each oil outlet channel is provided with an oil outlet.

[0048] like Figure 1 , Figure 6 as well as Figure 7As shown in the present application, each oil outlet is provided with an oil outlet. The bucket slide valve 3 controls the connection between the oil inlet channel and the first oil outlet 500 and the second oil outlet 600. The first oil outlet 500 is connected to the A1 oil outlet 510, which supplies oil to the large chamber of the bucket cylinder, i.e., the chamber with the piston rod. The second oil outlet 600 is connected to the B1 oil outlet 610, which supplies oil to the small chamber of the bucket cylinder, i.e., the chamber without the piston rod. The boom slide valve 4 controls the connection between the oil inlet channel and the third oil outlet 700 and the fourth oil outlet 800. The third oil outlet 700 is connected to the A2 oil outlet 710, which supplies oil to the large chamber of the boom cylinder. The fourth oil outlet 800 is connected to the B2 oil outlet 810, which supplies oil to the small chamber of the boom.

[0049] When the loader is working, the variable pump and the fixed displacement pump pump hydraulic oil into the main valve body 1. The hydraulic oil flows simultaneously to the bucket valve 3 and the boom valve 4 through the oil inlet passage. The specific flow direction of the hydraulic oil, that is, which outlet it flows out through, is determined by selecting the movement direction of the bucket valve 3 and the boom valve 4. It can be understood that the bucket valve 3 and the boom valve 4 are arranged coaxially and can move bidirectionally along the axial direction. The specific movement direction is determined by the operator's working needs for the bucket and the boom. The movement commands for the bucket valve 3 and the boom valve 4 can be achieved using existing technology, which will not be elaborated here.

[0050] In one embodiment, such as Figure 1 , Figure 6 As shown, the main valve body 1 is provided with a port overflow valve 5 connected to the oil outlet passage. There are two port overflow valves 5, which are located in the first oil outlet passage 500 and the second oil outlet passage 600, respectively.

[0051] As shown in the diagram, the two overflow valves 5 are located above the bucket slide valve 3 corresponding to the first oil outlet 500 and the second oil outlet 600. When the small chamber of the bucket returns oil, the valve core of the overflow valve 5 located on the same side as the B1 oil outlet 610 moves, and the oil returns directly to the oil tank through the overflow valve 5. Similarly, when the large chamber of the bucket returns oil, the valve core of the overflow valve 5 located on the same side as the A1 oil outlet 510 moves, opening the passage at the overflow valve 5, and the oil returns to the oil tank through the overflow valve 5, thus achieving overload protection for the large and small chambers of the bucket cylinder.

[0052] Furthermore, such as Figure 10As shown, the main valve body 1 is equipped with an LS safety valve 6, which is located on the same side as the confluence valve 2 and connected to the first oil inlet channel 300. When the pressure in the system rises abnormally to the overflow pressure of the LS safety valve 6, the oil overflows through the LS safety valve 6. The oil in the first oil inlet channel 300 then overflows preferentially through the LS safety valve 6. The pressure at the confluence valve 2, which is also located on the same side of the first oil inlet channel 300, is affected by the overflow and changes, resulting in a larger pressure difference on both sides of the confluence valve 2. This causes the variable pump to swing angle to decrease, the flow rate to decrease, and the fixed displacement pump to discharge oil to the oil tank through the confluence valve 2.

[0053] Furthermore, such as Figure 9 As shown, the main valve body 1 is equipped with a main relief valve 7, which is located on the opposite side of the confluence valve 2 and connected to the second oil inlet 400. When the pressure in the system continues to increase beyond the limit, oil can be discharged through the main relief valve 7 to ensure the safety of the oil circuit. The limit here can be set by those skilled in the art according to the actual application scenario.

[0054] like Figure 6 , Figure 7 And 11, Figure 12 As shown, the main valve body 1 is equipped with a pressure compensator 8, which is connected to the oil inlet passage. By changing the feed rate of the pressure compensator 8 in the oil inlet passage, the oil inlet volume is changed, the valve port pressure difference is adjusted, and thus the oil flow rate is adjusted. This ensures that when the machine performs compound actions, the flow distribution required by the boom and bucket is independent of load changes and only depends on the valve core opening of the bucket slide valve 3 and the boom slide valve 4, thereby improving the operational performance of the machine's compound actions.

[0055] Preferably, there are two pressure compensators 8. The two pressure compensators 8 control the valve port pressure difference at the bucket slide valve 3 and the valve port pressure difference at the boom slide valve 4 respectively, so as to control different flow channels separately and accurately adjust the oil flow.

[0056] The main valve body 1 is also provided with a return oil port 910 connected to the oil tank and a return oil passage 900 located inside the main valve body 1 and connected to the return oil port 910. A back pressure valve 9 is provided between the return oil passage 900 and the return oil port 910. When oil returns from the large chamber, the pressure in the return oil passage 900 is increased by the back pressure valve 9, allowing some oil to flow to other oil passages for replenishment. At this time, the port overflow valve 5 and the back pressure valve 9 work together to replenish oil to the large or small chambers of the bucket, which helps to improve the replenishment efficiency.

[0057] A hydraulic system is provided in a loader, and the hydraulic system is provided with a compound control valve as described above.

[0058] It is understood that the connection between the valve and the oil passage described in this application refers to the valve body being installed in the corresponding oil passage, and the opening and closing of the valve controlling whether the oil passage forms a passage at this point.

[0059] During operation, hydraulic oil is drawn into the main valve body 1 from the bottom of the oil tank through the oil filter by the variable displacement pump and the fixed displacement pump, and then enters the main valve body 1 with a certain pressure. The hydraulic oil first enters the bucket spool valve 3 along the oil inlet passage. The bucket spool valve 3 is a three-position six-way valve. Operating the bucket spool valve 3 to move its valve core axially to the right or left position can respectively realize the backward tilting and forward tilting actions of the bucket. When the bucket spool valve 3 is in the middle position, the hydraulic oil enters the boom spool valve 4. The boom spool valve 4 is a four-position six-way valve, and its four positions realize the lifting, closing, lowering, and floating actions of the boom respectively. In this process, hydraulic oil is preferentially supplied through the variable displacement pump. When the required flow rate of the system is insufficient, the fixed displacement pump participates in oil replenishment through the confluence valve 2 to supply hydraulic oil. At the same time, this scheme limits the total pressure of the entire system through the main relief valve 7, and provides overload protection and oil replenishment for the large and small chambers of the bucket cylinder through the two-port relief valves 5.

[0060] For any parts not mentioned in this application, existing technologies may be used or referenced.

[0061] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0062] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A constant-variable dual-pump composite control valve, characterized in that, The system includes a main valve body (1), which is connected to an oil tank and an oil cylinder via pipelines. The main valve body (1) has a P1 port (100) connected to a variable pump and a P2 port (200) connected to a fixed pump. Both the P1 port (100) and the P2 port (200) are oil inlets. The main valve body (1) has an oil inlet passage, which includes a first oil inlet passage (300) connected to the P1 port (100) and a second oil inlet passage (400) connected to the P2 port (200). A merging valve (2) is provided on the side of the main valve body (1) near the P2 port, and the merging valve (2) is connected to the second oil inlet passage (400).

2. The composite control valve according to claim 1, characterized in that, The first oil inlet channel (300) and the second oil inlet channel (400) are arranged side by side along the first direction. The main valve body (1) is also provided with an oil outlet channel arranged along the second direction. The end of the oil outlet channel is provided with an oil outlet. The oil outlet is connected to the oil cylinder through a pipeline. The first direction and the second direction are at an angle.

3. The composite control valve according to claim 2, characterized in that, The main valve body (1) is provided with a directional valve connecting the oil inlet passage and the oil outlet passage. The directional valve is located between the oil inlet passage and the oil outlet passage so that the oil inlet passage and the oil outlet passage can be connected or disconnected.

4. The composite control valve according to claim 3, characterized in that, The steering valve includes a bucket slide valve (3) and a boom slide valve (4) arranged in parallel. The oil outlet includes a first oil outlet (500) and a second oil outlet (600) located on both sides of the bucket slide valve (3), and a third oil outlet (700) and a fourth oil outlet (800) located on both sides of the boom slide valve (4). Each of the oil outlets is provided with an oil outlet.

5. The composite control valve according to claim 4, characterized in that, The main valve body (1) is provided with a port overflow valve (5) connected to the oil outlet passage. There are two port overflow valves (5), which are located in the first oil outlet passage (500) and the second oil outlet passage (600), respectively.

6. The composite control valve according to claim 4, characterized in that, The main valve body (1) is provided with an LS safety valve (6), which is located on the same side of the confluence valve (2) and is connected to the first oil inlet channel (300).

7. The composite control valve according to claim 4, characterized in that, The main valve body (1) is provided with a main relief valve (7), which is located on the opposite side of the confluence valve (2) and is connected to the second oil inlet passage (400).

8. The composite control valve according to claim 1, characterized in that, The main valve body (1) is equipped with a pressure compensator (8), which is connected to the oil inlet passage.

9. The composite control valve according to claim 1, characterized in that, The main valve body (1) is also provided with an oil return port (910) connected to the oil tank and an oil return passage (900) located in the main valve body (1) and connected to the oil return port (910). A back pressure valve (9) is provided between the oil return passage (900) and the oil return port (910).

10. A hydraulic system, characterized in that, The hydraulic system is installed on the loader, and the hydraulic system is equipped with a composite control valve as described in any one of claims 1-9.

Images