High flow hydraulic control system

Abstract

The application discloses a large-flow hydraulic control system, which comprises a constant-difference pressure reducing valve for automatically compensating load change, a two-way cartridge valve communicated with the constant-difference pressure reducing valve, a second control mechanism for adjusting the opening of the two-way cartridge valve and an actuator communicated with the oil outlet of the two-way cartridge valve. The two-way cartridge valve comprises a second valve body and a second valve core slidingly embedded in the second valve body. The second valve body comprises a second control cavity and a second throttling cavity. A second protruding ring is arranged on the second valve core. The second protruding ring divides the second control cavity into a first cavity and a second cavity. The oil inlet of the second throttling cavity is communicated with the oil outlet of the constant-difference pressure reducing valve. The oil outlet of the second throttling cavity is communicated with the actuator. The pressure difference between the first cavity and the second cavity is adjusted by the control oil introduced by the second control mechanism to realize the opening adjustment of the two-way cartridge valve. The application can meet the speed regulation requirement of the existing large-flow hydraulic system, does not need closed-loop control, has simple structure, is low in control cost compared with pump control or proportional servo valve control and is easy to realize.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic control, in particular, to a large flow hydraulic control system. BACKGROUND

[0002] Hydraulic transmission system is widely used in various types of mechanical and electrical equipment, and hydraulic valve is the core element for controlling the pressure, flow and direction of liquid in the hydraulic system, which has important influence on the performance, reliability and economy of the hydraulic system. With the development of society, in order to meet the construction needs of engineering, more and more large equipment with larger and larger specifications are needed, and the hydraulic control requirements of related equipment are increasing, and the flow to be controlled is also increasing, so the control of large flow is the most important.

[0003] At present, the conventional flow control is realized by using a speed regulating valve, and the opening degree of the throttle valve can be adjusted by a screw rod to realize the control of small flow. However, for the valve with a diameter of 20 mm or more, the area of the valve core is large, and the force required for the screw rod to overcome the oil pressure to move the valve core is too large (F>PA), so it is difficult for the operator to twist the screw rod. Therefore, it is not feasible to adjust the opening degree of the valve port by using a screw rod for the valve with a large diameter, and it is difficult to realize the control of large flow. The existing large flow control mode is divided into two kinds. One is pump control, which needs to do pump displacement closed loop control, and is difficult to be applied to multiple actuators. The other is valve control, which generally uses a large diameter proportional servo valve or a servo valve for closed loop control. The cost of the proportional servo valve with a diameter of 100 mm is more than 100,000 yuan, and the control precision depends on the control algorithm, and the debugging of the control algorithm is difficult. SUMMARY

[0004] The present application provides a large flow hydraulic control system to solve the technical problems of high cost and complex control of the existing large flow control system.

[0005] According to one aspect of the present application, a large flow hydraulic control system is provided, which comprises a constant differential pressure reducing valve for automatically compensating load changes, a two-way cartridge valve in communication with the constant differential pressure reducing valve, a second control mechanism for adjusting the opening degree of the two-way cartridge valve, and an actuator in communication with the oil outlet of the two-way cartridge valve. The two-way cartridge valve comprises a second valve body and a second valve core slidingly embedded in the second valve body. The second valve body comprises a second control cavity and a second throttling cavity. A second protruding ring is arranged on the second valve core. The second protruding ring separates the second control cavity into a first cavity and a second cavity. The oil inlet of the second throttling cavity is in communication with the oil outlet of the constant differential pressure reducing valve, and the oil outlet of the second throttling cavity is in communication with the actuator. The pressure difference between the first cavity and the second cavity is adjusted by the control oil introduced by the second control mechanism to realize the opening degree adjustment of the two-way cartridge valve.

[0006] Further, the second control mechanism comprises a proportional throttle valve, a damping hole and a first spring, an oil inlet of the proportional throttle valve is communicated with the first control oil path, an oil outlet of the proportional throttle valve is communicated with an oil inlet of the damping hole and the first cavity, an oil outlet of the damping hole is communicated with the second cavity and the oil tank, and two ends of the first spring are connected with the second valve body and the second valve core respectively to drive the second valve core to reset.

[0007] Further, the second control mechanism comprises a proportional throttle valve, a damping hole and a first spring, an oil inlet of the proportional throttle valve is communicated with the first control oil path, an oil outlet of the proportional throttle valve is communicated with an oil inlet of the damping hole and the first cavity, an oil outlet of the damping hole is communicated with the second cavity and the oil tank, and two ends of the first spring are connected with the second valve body and the second valve core respectively to drive the second valve core to reset.

[0008] Further, the second control mechanism comprises a proportional throttle valve, a damping hole and a first spring, an oil inlet of the proportional throttle valve is communicated with the first control oil path, an oil outlet of the proportional throttle valve is communicated with an oil inlet of the damping hole and the first cavity, an oil outlet of the damping hole is communicated with the second cavity and the oil tank, and two ends of the first spring are connected with the second valve body and the second valve core respectively to drive the second valve core to reset.

[0009] Further, the second control mechanism comprises a proportional throttle valve, a damping hole and a first spring, an oil inlet of the proportional throttle valve is communicated with the first control oil path, an oil outlet of the proportional throttle valve is communicated with an oil inlet of the damping hole and the first cavity, an oil outlet of the damping hole is communicated with the second cavity and the oil tank, and two ends of the first spring are connected with the second valve body and the second valve core respectively to drive the second valve core to reset.

[0010] Further, the differential pressure reducing valve comprises a first valve body, a first valve core and a first control mechanism for adjusting a preset differential pressure of the differential pressure reducing valve, the first valve body comprises a first control cavity and a first throttling cavity, a first protruding ring is arranged on the first valve core, the first protruding ring separates the first control cavity into a third cavity and a fourth cavity, the third cavity is communicated with an oil outlet of the second throttling cavity, an oil inlet of the first throttling cavity is communicated with a main oil path, an oil outlet of the first throttling cavity is communicated with an oil inlet of the second throttling cavity and the fourth cavity, and the first control mechanism adjusts the opening of the differential pressure reducing valve by adjusting a pressure difference between the third cavity and the fourth cavity.

[0011] Further, the first control mechanism comprises a second spring for driving the first valve core to reset, and two ends of the second spring are connected with the first valve body and the first valve core respectively.

[0012] Further, the first valve body further comprises a third control cavity, a third convex ring is arranged on the first valve core, the third convex ring separates the third control cavity into a fifth cavity and a sixth cavity, the first control mechanism comprises a second overflow valve, an oil inlet of the second overflow valve is communicated with the third control oil way and the fifth cavity, and an oil outlet of the second overflow valve is communicated with the sixth cavity and an oil tank.

[0013] Further, the first valve body and the second valve body are vertically arranged, the first cavity is arranged below the second cavity, the third cavity is arranged below the fourth cavity, and the fifth cavity is arranged below the sixth cavity.

[0014] Further, the areas of the two annular end faces of the second convex ring are equal, the areas of the two annular end faces of the first convex ring are equal, and the areas of the two annular end faces of the third convex ring are equal.

[0015] The present application has the following beneficial effects:

[0016] The large-flow hydraulic control system has the following beneficial effects: the constant differential pressure valve is used for automatically compensating the influence of load change on the flow of the two-way cartridge valve, the position of the second valve core is adjusted by adjusting the pressure difference between the first cavity and the second cavity through the second control mechanism, the opening of the two-way cartridge valve is adjusted, the flow of the two-way cartridge valve is stabilized, when in use, the control oil is introduced into the second control mechanism, the control oil enters the first cavity of the two-way cartridge valve, the oil outlet of the second throttling cavity is slowly opened, the pressure of the second cavity is slowly increased or the pressure of the first cavity is gradually reduced with the increase of the second valve core, so that the pressure of the second cavity is consistent with the pressure of the second cavity or the second valve core is in a force balance state, at this time, the second valve core remains constant; by adjusting the pressure of the control oil, the oil outlet of the second throttling cavity also changes, so that the control oil pressure of the first control oil way is one-to-one corresponding to the opening of the two-way cartridge valve, stepless adjustment or proportional adjustment of large flow can be realized, the speed regulation demand of the existing large-flow hydraulic system is met, the maximum regulation flow is greater than 10000L / min, closed-loop control is not needed, operation is simple, the requirement for oil cleanliness is not high, the cost is low compared with pump control or proportional servo valve control, and the large-flow hydraulic control system is easy to realize.

[0017] In addition to the objects, features, and advantages described above, the present application has other objects, features and advantages. Hereinafter, the present application will be further described in detail with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments illustrated in the drawings are provided to explain the present application and should not be considered limiting of the present application. In the drawings:

[0019] Figure 1is a structure schematic view of a large flow hydraulic control system of a preferred embodiment of the present application;

[0020] Figure 2 is Figure 1 a structure schematic view of a two-way cartridge valve shown in the figure;

[0021] Figure 3 is a structure schematic view of a large flow hydraulic control system of a preferred embodiment of the present application;

[0022] Figure 4 is Figure 3 a structure schematic view of a two-way cartridge valve shown in the figure;

[0023] Figure 5 is a structure schematic view of a large flow hydraulic control system of a preferred embodiment of the present application;

[0024] Figure 6 is Figure 1 a structure schematic view of a two-way cartridge valve shown in the figure;

[0025] Figure 7 is a structure schematic view of a large flow hydraulic control system of a preferred embodiment of the present application;

[0026] Figure 8 is Figure 1 a structure schematic view of a two-way cartridge valve shown in the figure.

[0027] Marking explanation:

[0028] 1, constant difference pressure reducing valve; 11, first valve body; 111, first throttling cavity; 112, third cavity; 113, fourth cavity; 114, fifth cavity; 115, sixth cavity; 12, first valve core; 121, first convex ring; 122, third convex ring; 13, first control mechanism; 131, second spring; 132, second overflow valve; 2, two-way cartridge valve; 21, second valve body; 211, second throttling cavity; 212, first cavity; 213, second cavity; 22, second valve core; 221, second convex ring; 3, second control mechanism; 31, proportional speed regulating valve; 32, damping hole; 33, first spring; 34, proportional overflow valve; 35, first overflow valve; 36, push rod; 4, execution element; 5, oil tank. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following.

[0030] Please see Figures 1 to 8The large flow hydraulic control system of the embodiment comprises a constant difference pressure reducing valve 1 for automatically compensating load variation, a two-way cartridge valve 2 in communication with the constant difference pressure reducing valve 1, a second control mechanism 3 for adjusting the opening of the two-way cartridge valve 2, and an actuator 4 in communication with the oil outlet of the two-way cartridge valve 2. The two-way cartridge valve 2 comprises a second valve body 21 and a second valve core 22 slidingly embedded in the second valve body 21. The second valve body 21 comprises a second control cavity and a second throttling cavity 211. The second valve core 22 is provided with a second protruding ring 221. The second protruding ring 221 separates the second control cavity into a first cavity 212 and a second cavity 213. The oil inlet A2 of the second throttling cavity 211 is in communication with the oil outlet of the constant difference pressure reducing valve 1. The oil outlet B2 of the second throttling cavity 211 is in communication with the actuator 4. The control oil introduced by the second control mechanism 3 adjusts the pressure difference between the first cavity 212 and the second cavity 213 to realize the opening adjustment of the two-way cartridge valve 2.

[0031] The large flow hydraulic control system of the embodiment automatically compensates the influence of load variation on the flow of the two-way cartridge valve 2 through the constant difference pressure reducing valve 1. The position of the second valve core 22 is adjusted by adjusting the pressure difference between the first cavity 212 and the second cavity 213 through the second control mechanism 3, so as to adjust the opening of the two-way cartridge valve 2, thereby ensuring the stability of the flow of the two-way cartridge valve 2. In use, the second control mechanism 3 introduces control oil, which enters the first cavity 212 of the two-way cartridge valve 2. The oil outlet B2 of the second throttling cavity 211 slowly opens. As the second valve core 22 increases, the pressure of the second cavity 213 slowly rises or the pressure of the first cavity 212 gradually decreases, so that the pressure of the second cavity 213 is consistent with that of the second cavity 213 or the second valve core 22 is in a force balance state. At this time, the second valve core 22 remains constant. By adjusting the pressure of the control oil, the oil outlet B2 of the second throttling cavity 211 also changes, so that the control oil pressure of the first control oil path corresponds to the opening of the two-way cartridge valve 2, which can realize stepless adjustment or proportional adjustment of large flow, meet the speed regulation demand of the existing large flow hydraulic system, and has a maximum regulation flow >10000L / min. Without closed-loop control, the operation is simple, the requirement for oil cleanliness is not high, the cost is low compared with pump control or proportional servo valve control, and it is easy to realize. Optionally, the actuator 4 is an oil cylinder or a hydraulic motor.

[0032] As Figure 1 and Figure 2As shown, in the embodiment, the second control mechanism 3 comprises a proportional throttle valve 31, a damping hole 32 and a first spring 33. The oil inlet A3 of the proportional throttle valve 31 is communicated with the first control oil path, the oil outlet B3 of the proportional throttle valve 31 is communicated with the oil inlet A4 of the damping hole 32 and the first cavity 212, the oil outlet B4 of the damping hole 32 is communicated with the second cavity 213 and the oil tank 5, and the two ends of the first spring 33 are connected with the second valve body 21 and the second valve core 22 respectively to drive the second valve core 22 to reset. In the initial state, the constant difference pressure reducing valve 1 is kept open, and the two-way cartridge valve 2 is kept closed under the action of the first spring 33. When the flow needs to be adjusted, the first control oil path provides the control oil P2, the small flow proportional throttle valve 31 is adjusted, so that the flow of the control oil P2 is constant. At this time, the flow direction of the control oil P2 is A3-B3-A4 (the first cavity 212)-B4 (the second cavity 213)-the oil tank 5. When the flow through the damping hole 32 is constant, the pressure at the oil inlet A4 of the damping hole 32 is also constant, so the pressure of the first cavity 212 is constant (for example, when the flow through the damping hole 32 is 9L / min, the diameter of the damping hole 32 is 3mm, and the pressure at the oil inlet of the damping hole 32 is 4.01Ba according to the calculation formula of the pressure loss through the thin-walled small hole). After the first cavity 212 has pressure, the second valve core 22 is pushed to move towards the second cavity 213, the first spring 33 is compressed to provide a reverse force for the second valve core 22, and when the pressure of the first cavity 212 is equal to the force of the first spring 33, the second valve core 22 stops moving and remains stable. At this time, the opening of the second valve core 22 and the second valve body 21 is constant, and the opening adjustment of the two-way cartridge valve 2 can be realized by adjusting the flow of the proportional throttle valve 31. The structure is simple, only one pilot oil is needed, the pressure difference between the first cavity 212 and the second cavity 213 is balanced through the first spring 33, the large flow control can be realized, the opening of the two-way cartridge valve 2 can be stably controlled, and the influence of the pressure fluctuation of the control oil P2 oil inlet is avoided.

[0033] As Figure 3 and Figure 4As shown, in the embodiment, the second control mechanism 3 comprises a proportional relief valve 34 and a first spring 33, the oil inlet A5 of the proportional relief valve 34 is communicated with the first control oil path and the first cavity 212, the oil outlet B5 of the proportional relief valve 34 is communicated with the second cavity 213 and the oil tank 5; in the initial state, the constant differential pressure reducing valve 1 is kept open, and the two-way cartridge valve 2 is kept closed under the action of the first spring 33; when the flow needs to be adjusted, the first control oil path provides the control oil P2, the proportional relief valve 34 is adjusted to keep the pressure of the control oil P2 constant, at this time, the flow direction of the control oil P2 is A5 (the first cavity 212)-B5 (the second cavity 213)-the oil tank 5, and the pressure of the first cavity 212 is constant; after the first cavity 212 has pressure, the second valve core 22 is pushed to move to the second cavity 213, the first spring 33 is compressed to provide a reverse force for the second valve core 22, when the pressure of the first cavity 212 is equal to the force of the first spring 33, the second valve core 22 stops moving and keeps stable, at this time, the opening of the second valve core 22 and the second valve body 21 is constant, and the opening adjustment of the two-way cartridge valve 2 can be realized by adjusting the pressure of the proportional relief valve 34; if the flow demand of the control oil P2 is small and can be below 2L / min, if the proportional relief valve 34 is stuck, the control oil P2 is pressure-boosted, the two-way cartridge valve 2 can be fully opened, and the main system is not pressure-boosted, which is safer.

[0034] As Figure 5 and Figure 6As shown, in the embodiment, the second control mechanism 3 comprises a proportional throttle valve 31, a damping hole 32, a first spring 33, a first overflow valve 35 and a push rod 36. The oil inlet A3 of the proportional throttle valve 31 is communicated with the first control oil path, the oil outlet B3 of the proportional throttle valve 31 is communicated with the oil inlet A4 of the damping hole 32 and the first cavity 212, the oil outlet B4 of the damping hole 32 is communicated with the oil outlet B6 of the first overflow valve 35 and the oil tank 5, the oil inlet A6 of the first overflow valve 35 is communicated with the second control oil path and the second cavity 213, and the two ends of the first spring 33 are connected with the second valve body 21 and the second valve core 22 respectively to drive the second valve core 22 to reset. The pressure regulating spring on the first overflow valve 35 is connected with the second valve core 22 through the push rod 36. In the initial state, the constant difference pressure reducing valve 1 is kept open, the second control oil path provides the control oil P3, the first cavity 212 and the second cavity 213 of the two-way cartridge valve 2 are communicated, the two circular ring end faces of the second convex ring 221 are subjected to equal forces, the first spring 33 only needs to overcome the friction between the second valve core 22 and the second valve body 21, and the second valve core 22 is kept closed under the action of the first spring 33. When the flow needs to be adjusted, the first control oil path provides the control oil P2, the small flow proportional throttle valve 31 is adjusted so that the flow of the control oil P2 is constant. At this time, the flow direction of the control oil P2 is A3-B3-A4 (the first cavity 212)-B4 (the second cavity 213)-the oil tank 5. When the flow through the damping hole 32 is constant, the pressure at the oil inlet A4 of the damping hole 32 is also constant, and then the pressure of the first cavity 212 is constant. After the first cavity 212 has pressure, the second valve core 22 is driven to move to the second cavity 213, the push rod 36 is compressed to compress the pressure regulating spring of the first overflow valve 35, the pressure of the oil inlet A6 (the second cavity 213) of the first overflow valve 35 is increased, and when the pressure of the second cavity 213 is increased to be consistent with the pressure of the first cavity 212, the second valve core 22 stops moving and remains stable. At this time, the opening of the second valve core 22 and the second valve body 21 is constant, and the opening of the two-way cartridge valve 2 can be adjusted by adjusting the flow of the proportional throttle valve 31. The first spring 33 has low requirements, only needs a small force to reset, and only needs to adjust the flow of the proportional throttle valve 31 to realize the control of large flow, and the scheme is easier to realize.

[0035] As Figure 7 and Figure 8As shown, in the embodiment, the second control mechanism 3 comprises a first spring 33, a first overflow valve 35 and a push rod 36. Two ends of the first spring 33 are connected with the second valve body 21 and the second valve core 22 respectively to drive the second valve core 22 to reset. An oil inlet A6 of the first overflow valve 35 is communicated with the second control oil path P3 and the first cavity 212. An oil outlet B6 of the first overflow valve 35 is communicated with the second cavity 213 and the oil tank 5. In the initial state, the constant differential pressure reducing valve 1 is kept open, and the two-way cartridge valve 2 is kept closed under the action of the first spring 33. When the flow needs to be adjusted, the second control oil path is given a control oil P3. At this time, the flow direction of the control oil P3 is A6 (the first cavity 212)-B6-the second cavity 213-the oil tank 5. The structure of the first overflow valve 35 is similar to that of the pump power valve. The pressure regulating spring of the first overflow valve 35 is connected with the push rod 36. The pressure of the first overflow valve 35 is set by manually adjusting the pressure regulating spring. The pressure of the first cavity 212 is increased to drive the second valve core 22 to move towards the second cavity 213, and the push rod 36 is driven to release the pressure regulating spring of the first overflow valve 35. With the upward displacement of the second valve core 22, the compression amount of the pressure regulating spring of the first overflow valve 35 is smaller and smaller, and the pressure of the first cavity 212 is smaller and smaller. When the displacement of the second valve core 22 is equal to the compression amount of the pressure regulating spring of the first overflow valve 35, the pressure of the first cavity 212 is 0, the pressure of the first cavity 212 is equal to that of the second cavity 213, the second valve core 22 stops moving and keeps stable, and the opening of the second valve core 22 and the second valve body 21 is constant. The opening adjustment of the two-way cartridge valve 2 can be realized by adjusting the compression amount of the pressure regulating spring of the first overflow valve 35. The compression amount of the pressure regulating spring of the first overflow valve 35 is manually adjusted to realize the control of the large flow. The opening adjustment of the two-way cartridge valve 2 can be realized by using an overflow valve and a control oil path. The adaptability is strong, and the requirement for the control oil flow is low.

[0036] As Figure 2 and Figure 4As shown, in the embodiment, the constant differential pressure reducing valve 1 comprises a first valve body 11, a first valve core 12, and a first control mechanism 13 for adjusting the preset pressure difference of the constant differential pressure reducing valve 1. The first valve body 11 comprises a first control cavity and a first throttling cavity 111. The first valve core 12 is provided with a first protruding ring 121, which separates the first control cavity into a third cavity 112 and a fourth cavity 113. The third cavity 112 is in communication with the oil outlet B2 of the second throttling cavity 211. The oil inlet A1 of the first throttling cavity 111 is in communication with the main oil circuit. The oil outlet B1 of the first throttling cavity 111 is in communication with the oil inlet A2 of the second throttling cavity 211 and the fourth cavity 113. The first control mechanism 13 adjusts the opening of the constant differential pressure reducing valve 1 by adjusting the pressure difference between the third cavity 112 and the fourth cavity 113. In the initial state, the main oil circuit has no pressure oil. At this time, the third cavity 112 and the fourth cavity 113 are in communication, the forces on the two circular end faces of the first protruding ring 121 are equal, and the constant differential pressure reducing valve 1 is fully open under the action of the first control mechanism 13. In use, the main oil circuit provides pressure oil P1. When the flow of the constant differential pressure reducing valve 1 is less than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is less than the pressure generated by the first control mechanism 13, and the constant differential pressure reducing valve 1 is fully open. When the flow is greater than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is greater than the pressure generated by the first control mechanism 13, and the opening of the first valve core 12 is reduced under the drive of the first control mechanism 13, thereby reducing the flow until the flow is equal to the set value.

[0037] As shown in Figure 2 and Figure 4 , in the embodiment, the first control mechanism 13 comprises a second spring 131 for driving the first valve core 12 to reset. The two ends of the second spring 131 are connected to the first valve body 11 and the first valve core 12, respectively. In the initial state, the main oil circuit has no pressure oil. At this time, the third cavity 112 and the fourth cavity 113 are in communication, the forces on the two circular end faces of the first protruding ring 121 are equal, and the first valve core 12 is fully open under the action of the second spring 131 due to the compression of the second spring 131. In use, the main oil circuit provides pressure oil P1. When the flow of the constant differential pressure reducing valve 1 is less than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is less than the elastic force generated by the compression of the second spring 131, and the constant differential pressure reducing valve 1 is fully open. When the flow is greater than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is greater than the elastic force generated by the compression of the second spring 131, and the opening of the first valve core 12 is reduced under the drive of the second spring 131, thereby reducing the flow until the flow is equal to the set value. The structure is simple, the cost is low, and the preset pressure value of the constant differential pressure reducing valve 1 is adjusted by adjusting the deformation amount of the second spring 131.

[0038] As shown in Figure 6 and Figure 8As shown, in the embodiment, the first valve body 11 further comprises a third control chamber, the first valve core 12 is provided with a third protruding ring 122, the third protruding ring 122 separates the third control chamber into a fifth chamber 114 and a sixth chamber 115, the first control mechanism 13 comprises a second overflow valve 132, an oil inlet A5 of the second overflow valve 132 is communicated with the third control oil path P4 and the fifth chamber 114, an oil outlet B5 of the second overflow valve 132 is communicated with the sixth chamber 115 and the oil tank 5; in the initial state, the main oil path has no pressure oil, the third control oil path has a given control oil P4, the pressure of the control oil P4 is determined by the second overflow valve 132 and does not change after being set, the differential pressure valve 1 is fully opened under the action of the control oil P4; the pressure of the fourth chamber 113 is equal to the pressure of the oil inlet A2 of the two-way cartridge valve 2, the pressure of the third chamber 112 is equal to the pressure of the oil outlet B2 of the two-way cartridge valve 2, the pressure difference between the third chamber 112 and the fourth chamber 113 is equal to the pressure difference between the oil inlet A2 and the oil outlet B2 of the two-way cartridge valve 2, when the flow of the differential pressure valve 1 is less than the set value, the pressure difference between the third chamber 112 and the fourth chamber 113 is less than the pressure difference between the fifth chamber 114 and the sixth chamber 115, the differential pressure valve 1 is fully opened; when the flow is greater than the set value, the pressure difference between the third chamber 112 and the fourth chamber 113 is greater than the pressure difference between the fifth chamber 114 and the sixth chamber 115, the first valve core 12 starts to move towards the third chamber 112, the opening of the differential pressure valve 1 is reduced, the flow is reduced, until the flow is equal to the set value; the pressure difference between the fifth chamber 114 and the sixth chamber 115 is adjusted by the second overflow valve 132, the preset pressure adjustment of the differential pressure valve 1 is realized, and the use range is wide.

[0039] As shown in Figure 6 and Figure 8 , in the embodiment, the first valve body 11 and the second valve body 21 are vertically arranged, the first chamber 212 is arranged below the second chamber 213, the third chamber 112 is arranged below the fourth chamber 113, and the fifth chamber 114 is arranged below the sixth chamber 115; if the valve body is horizontally arranged, the valve core will be pressed on the inner wall of the valve body due to the action of gravity, which will increase the friction between the valve core and the valve body, not only shortening the service life, but also possibly affecting the reset action of the valve core; therefore, the first valve body 11 and the second valve body 21 are vertically arranged, which can reduce the friction between the valve core and the valve body, thereby improving the service life and ensuring that the valve core can be reset smoothly.

[0040] As shown in Figure 6 and Figure 8 , in the embodiment, the areas of the two annular end faces of the second protruding ring 221 are equal, the areas of the two annular end faces of the first protruding ring 121 are equal, and the areas of the two annular end faces of the third protruding ring 122 are equal; such protruding ring structure is simple, convenient to process and easy to calculate the pressure difference.

[0041] Embodiment one

[0042] The first spring 33 and the second spring 131 meet the use conditions (the second spring 131 can provide a force of ≥7 bar under a certain compression amount when the differential pressure reducing valve with a 120 mm diameter is matched; the first spring 33 can provide a force of ≥7 bar under a certain compression amount when the two-way cartridge valve 2 with a 120 mm diameter is matched), and the flow of the two-way cartridge valve 2 is regulated by the proportional speed regulating valve 31.

[0043] As shown in Figure 2 The main oil passage communicates with the oil inlet A1 of the differential pressure reducing valve 1, the oil outlet B1 of the differential pressure reducing valve 1 communicates with the oil inlet A2 of the two-way cartridge valve 2 and the fourth cavity 113 of the differential pressure reducing valve 1, and the oil outlet B2 of the two-way cartridge valve 2 communicates with the actuator 4 and the third cavity 112 of the differential pressure reducing valve 1. The first control oil passage communicates with the oil inlet A3 of the proportional speed regulating valve 31, the oil outlet of the proportional speed regulating valve 31 communicates with the oil inlet A4 of the damping hole 32 and the first cavity 212 of the two-way cartridge valve 2, and the oil outlet B4 of the damping hole 32 communicates with the second cavity 213 of the two-way cartridge valve 2 and the oil tank 5. The second spring 131 is in the third cavity 112 of the differential pressure reducing valve 1, and the first spring 33 is in the upper part of the second spool 22.

[0044] In the initial state, the main oil passage and the first control oil passage have no pressure oil, at this time the pressure of the third cavity 112 and the fourth cavity 113 is 0, the forces on both ends of the first convex ring 121 are equal, and the first spool 12 is fully open under the action of the second spring 131 which has a compression amount; the first cavity 212 communicates with the second cavity 213, the forces on both ends of the second convex ring 221 are equal, and the second spool 22 is closed under the action of the first spring 33.

[0045] When the main oil passage provides pressure oil P1, because the differential pressure reducing valve 1 is in an open state in the initial state, the fourth cavity 113 communicates with B1 and A1, pressure oil enters the fourth cavity 113, and the first spool 12 is closed under the action of the pressure oil in the fourth cavity 113. The first cavity 212 of the two-way cartridge valve 2 communicates with the second cavity 213, and the two-way cartridge valve 2 remains closed.

[0046] When the flow of the two-way cartridge valve 2 needs to be adjusted, the valve opening adjustment process of the two-way cartridge valve 2 is as follows: the first control oil path is given the control oil P2, the small flow proportional speed valve 31 is adjusted so that the flow of the control oil P2 is constant, at this time, the flow direction of the control oil P2 is A3-B3-A4 (the first cavity 212)-B4 (the second cavity 213)-the oil tank 5, when the flow through the damping hole 32 is constant, the pressure at the oil inlet A4 point of the damping hole 32 is constant, and then the pressure in the first cavity 212 is constant (for example, when the flow through the damping hole 32 is 9 L / min, the diameter of the damping hole 32 is 3 mm, and the pressure at the oil inlet of the damping hole 32 is 4.01 Ba according to the thin-walled orifice pressure loss calculation formula); after the first cavity 212 has pressure, the second valve core 22 is pushed to move towards the second cavity 213, and the first spring 33 generates compression to provide a reverse force to the second valve core 22; when the pressure in the first cavity 212 is equal to the force of the first spring 33, the second valve core 22 stops moving and remains stable, at this time, the opening of the second valve core 22 and the second valve body 21 is constant.

[0047] Adjusting the flow of the proportional speed valve 31→the pressure in the first cavity 212 is different→the displacement of the second valve core 22 is different→the opening of the two-way cartridge valve 2 is different; by adjusting the flow of the proportional speed valve 31, the opening adjustment of the two-way cartridge valve 2 can be realized.

[0048] After the second valve core 22 is opened, A2 and B2 are communicated, and since there is no pressure oil flowing at this time, the pressures at A2 and B2 are equal, that is, the pressures in the third cavity 112 and the fourth cavity 113 of the first valve core 12 are equal, and the first valve core 12 is opened under the action of the spring 131, and the overall main oil path is: pressure oil P1-A1-B1-A2-B2-executive element, and the first valve core 12 starts to automatically adjust the opening to match the corresponding flow.

[0049] The preset pressure adjustment process of the constant-difference pressure reducing valve 1 is as follows: the pressure in the fourth cavity 113 is equal to the pressure at the oil inlet A2 of the two-way cartridge valve 2, the pressure in the third cavity 112 is equal to the pressure at the oil outlet B2 of the two-way cartridge valve 2, and the pressure difference between the fourth cavity 113 and the third cavity 112 is equal to the pressure difference between the oil inlet A2 and the oil outlet B2 of the two-way cartridge valve 2; when the flow of the constant-difference pressure reducing valve 1 is less than the set value, the pressure difference between the fourth cavity 113 and the third cavity 112 is less than the elastic force generated by the compression of the second spring 131, and the constant-difference pressure reducing valve 1 is fully opened; when the flow is greater than the set value, the pressure difference between the fourth cavity 113 and the third cavity 112 is greater than the elastic force generated by the compression of the second spring 131, and the first valve core 12 starts to move downwards, the opening of the constant-difference pressure reducing valve 1 is reduced, and the flow is reduced, until the flow is equal to the set value (the pressure difference between the fourth cavity 113 and the third cavity 112 is equal to the elastic force generated by the compression of the second spring 131).

[0050] When the pressure difference between the inlet A2 and outlet B2 of the two-way cartridge valve 2 is constant, and the opening of the two-way cartridge valve 2 is constant, the flow through the two-way cartridge valve 2 is constant, so adjusting the opening of the two-way cartridge valve 2 can adjust the system flow; the embodiment has a simple structure, only one pilot oil is needed, the pressure difference between the first cavity 212 and the second cavity 213 is balanced by the first spring 33, so that the large flow control can be realized, and the opening of the two-way cartridge valve 2 can be stably controlled without being affected by the pressure fluctuation of the control oil inlet.

[0051] Embodiment two

[0052] When the first spring 33 and the second spring 131 meet the use conditions (the second spring 131 can provide a force of ≥7bar under a certain compression amount when matching the 120mm diameter differential pressure valve; the first spring 33 can provide a force of ≥7bar under a certain compression amount when matching the 120mm diameter two-way cartridge valve 2), the flow of the two-way cartridge valve 2 is adjusted by the proportional overflow valve 34.

[0053] As shown in Figure 4 , the main oil passage is communicated with the inlet A1 of the differential pressure valve 1, the outlet B1 of the differential pressure valve 1 is communicated with the inlet A2 of the two-way cartridge valve 2 and the fourth cavity 113 of the differential pressure valve 1, and the outlet B2 of the two-way cartridge valve 2 is communicated with the actuator 4 and the third cavity 112 of the differential pressure valve 1. The first control oil passage is communicated with the inlet A5 of the proportional overflow valve 34 and the first cavity 212 of the two-way cartridge valve 2, and the outlet B5 of the proportional overflow valve 34 is communicated with the second cavity 213 of the two-way cartridge valve 2 and the oil tank 5. The second spring 131 is in the third cavity 112 of the differential pressure valve 1, and the first spring 33 is in the upper part of the second spool 22.

[0054] In the initial state, the main oil passage and the first control oil passage have no pressure oil, at this time the pressure of the third cavity 112 and the fourth cavity 113 is 0, the forces on both ends of the first convex ring 121 are equal, and the first spool 12 is fully open under the action of the second spring 131 due to the compression amount of the second spring 131; the pressure of the first cavity 212 and the second cavity 213 is 0, the forces on both ends of the second convex ring 221 are equal, and the second spool 22 is closed under the action of the first spring 33.

[0055] When the main oil passage provides pressure oil P1, since the differential pressure valve 1 is in the open state in the initial state, the fourth cavity 113 is communicated with B1 and A1, pressure oil enters the fourth cavity 113, and the first spool 12 is closed under the action of the pressure oil in the fourth cavity 113. The pressure of the first cavity 212 and the second cavity 213 of the two-way cartridge valve 2 is 0, and the two-way cartridge valve 2 remains closed.

[0056] When the flow of the two-way cartridge valve 2 needs to be adjusted, the opening degree adjustment process of the two-way cartridge valve 2: the first control oil path is given the control oil P2, the proportional overflow valve 34 is adjusted, so that the pressure of the control oil P2 is constant, at this time the flow direction of the control oil P2 is A5 (the first cavity 212)-B5 (the second cavity 213)-the oil tank 5, the pressure of the first cavity 212 is constant; After the first cavity 212 has pressure, the second valve core 22 is pushed to move towards the second cavity 213, the first spring 33 generates compression to provide a reverse force for the second valve core 22, when the pressure of the first cavity 212 is equal to the force of the first spring 33, the second valve core 22 stops moving and remains stable, at this time the opening degree of the second valve core 22 and the second valve body 21 is constant.

[0057] The pressure of the proportional overflow valve 34→the pressure of the first cavity 212 is different→the displacement of the second valve core 22 is different→the opening degree of the two-way cartridge valve 2 is different; By adjusting the pressure of the proportional overflow valve 34, the opening degree adjustment of the two-way cartridge valve 2 can be realized.

[0058] After the second valve core 22 is opened, A2 and B2 are communicated, and since there is no pressure oil flowing at this time, the pressures of A2 and B2 are equal, that is, the pressures of the third cavity 112 and the fourth cavity 113 of the first valve core 12 are equal, the first valve core 12 is opened under the action of the spring 131, and the overall main oil path is: pressure oil P1-A1-B1-A2-B2-executive element, and the first valve core 12 starts to automatically adjust the opening degree to match the corresponding flow.

[0059] The preset pressure adjustment process of the constant-difference pressure reducing valve 1: the pressure of the fourth cavity 113 is equal to the pressure of the two-way cartridge valve 2 inlet A2, the pressure of the third cavity 112 is equal to the pressure of the two-way cartridge valve 2 outlet B2, and the pressure difference between the fourth cavity 113 and the third cavity 112 is equal to the pressure difference between the two-way cartridge valve 2 inlet A2 and outlet B2; When the flow of the constant-difference pressure reducing valve 1 is less than the set value, the pressure difference between the fourth cavity 113 and the third cavity 112 is less than the elastic force generated by the compression of the second spring 131, and the constant-difference pressure reducing valve 1 is fully opened; When the flow is greater than the set value, the pressure difference between the fourth cavity 113 and the third cavity 112 is greater than the elastic force generated by the compression of the second spring 131, and the first valve core 12 starts to move downward, the opening degree of the constant-difference pressure reducing valve 1 decreases, and the flow decreases, until the flow is equal to the set value (the pressure difference between the fourth cavity 113 and the third cavity 112 is equal to the elastic force generated by the compression of the second spring 131).

[0060] When the pressure difference between the two-way cartridge valve 2 inlet A2 and outlet B2 is constant, and the opening degree of the two-way cartridge valve 2 is constant, the flow through the two-way cartridge valve 2 is constant, so adjusting the opening degree of the two-way cartridge valve 2 can adjust the system flow; The structure of the embodiment is simple, the control oil flow demand is small, and the control oil flow can be below 2L / min. If the proportional overflow valve 34 is stuck, the control oil pressure is blocked, the valve core of the two-way cartridge valve 2 can be fully opened, the main system is not blocked, and it is more safe.

[0061] Example 3

[0062] When the first spring 33 and the second spring 131 do not meet the operating conditions (the second spring 131 provides a pressure of <7 bar when matched with a 120 mm diameter constant differential pressure reducing valve; the first spring 33 provides a pressure of <7 bar when matched with a 120 mm diameter two-way cartridge valve 2), the flow rate of the two-way cartridge valve 2 is regulated by three-way control oil.

[0063] like Figure 6 As shown, the main oil circuit is connected to the inlet A1 of the differential pressure reducing valve 1. The outlet B1 of the differential pressure reducing valve 1 is connected to the inlet A2 of the two-way cartridge valve 2 and the fourth chamber 113 of the differential pressure reducing valve 1. The outlet B2 of the two-way cartridge valve 2 is connected to the actuator 4 and the third chamber 112 of the differential pressure reducing valve 1. The first control oil circuit is connected to the inlet A3 of the proportional speed control valve 31. The outlet B3 of the proportional speed control valve 31 is connected to the inlet A4 of the damping orifice 32 and the first chamber 212 of the two-way cartridge valve 2. The outlet B4 of the damping orifice 32 is connected to the outlet B6 of the first relief valve 35 and the oil tank 6. The second control oil circuit is connected to the inlet A6 of the first relief valve 35 and the second chamber 213 of the two-way cartridge valve 2. The third control oil circuit is connected to the fifth chamber 114 of the differential pressure reducing valve 1 and the oil inlet A5 of the second relief valve 132. The oil outlet B5 of the second relief valve 132 is connected to the sixth chamber 115 of the differential pressure reducing valve 1 and the oil tank 5. The two ends of the push rod 36 are rigidly connected to the second valve core 22 and the pressure regulating spring of the first relief valve 35, respectively.

[0064] Initially, the main oil circuit and the first control oil circuit have no pressurized oil, while the second and third control oil circuits have pressurized oil. The pressure of the control oil P4 given by the third control oil circuit is determined by the second relief valve 132 and remains unchanged after being set. Under the action of the control oil P4, the first valve core 12 of the differential pressure reducing valve 1 is fully open. The second control oil circuit is given control oil P3, and the pressure in the first chamber 212 and the second chamber 213 of the two-way cartridge valve 2 is 0. The two annular end faces of the second convex ring 221 are subjected to equal forces, and the first spring 33 only needs to overcome the friction between the second valve core 22 and the second valve body 21. Under the action of the first spring 33, the second valve core 22 remains closed.

[0065] When the main oil circuit supplies pressurized oil P1, since the differential pressure reducing valve 1 is initially open, the fourth chamber 113 is connected to B1 and A1, and pressurized oil enters the fourth chamber 113. The first valve core 12 closes under the action of the pressurized oil in the fourth chamber 113. The pressure in the first chamber 212 and the second chamber 213 of the two-way cartridge valve 2 is 0, and the two-way cartridge valve 2 remains closed.

[0066] When the flow of the two-way cartridge valve 2 needs to be adjusted, the opening degree adjustment process of the two-way cartridge valve 2 valve port: the first control oil way provides control oil P2, adjusts the small flow proportional speed valve 31, so that the flow of control oil P2 is constant, at this time the flow direction of control oil P2 is A3-B3-A4(first cavity 212)-B4(second cavity 213)-oil tank 5, when the flow through the damping hole 32 is constant, then the pressure of the oil inlet A4 point of the damping hole 32 is constant, and the pressure of the first cavity 212 is constant; After the first cavity 212 has pressure, the second valve core 22 is pushed to move towards the second cavity 213, driving the push rod 36 to compress the pressure regulating spring of the first overflow valve 35, so that the pressure of the oil inlet A6(second cavity 213) of the first overflow valve 35 rises, when the pressure of the second cavity 213 rises to the same as the pressure of the first cavity 212, the second valve core 22 stops moving and remains stable, at this time the opening degree of the second valve core 22 and the second valve body 21 is constant.

[0067] Adjust the flow of the proportional speed valve 31→the pressure of the first cavity 212 is different→the displacement of the second valve core 22 is different→the pressure of the second cavity 213 is consistent with the first cavity 212→the opening degree of the two-way cartridge valve 2 is different.

[0068] After the second valve core 22 is opened, A2 and B2 are communicated, and since there is no pressure oil flowing at this time, the pressures of A2 and B2 are equal, that is, the pressures of the third cavity 112 and the fourth cavity 113 of the first valve core 12 are equal, and the first valve core 12 is opened under the action of the pressure difference between the fifth cavity 114 and the sixth cavity 115, and the overall main oil way is: pressure oil P1-A1-B1-A2-B2-executive element, and the first valve core 12 starts to automatically adjust the opening degree to match the corresponding flow.

[0069] The adjustment process of the constant difference pressure reducing valve 1: the pressure of the fourth cavity 113 is equal to the pressure of the oil inlet A2 of the two-way cartridge valve 2, the pressure of the third cavity 112 is equal to the pressure of the oil outlet B2 of the two-way cartridge valve 2, and the pressure difference between the third cavity 112 and the fourth cavity 113 is equal to the pressure difference between the oil inlet A2 and the oil outlet B2 of the two-way cartridge valve 2, when the flow of the constant difference pressure reducing valve 1 is less than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is less than the pressure difference between the fifth cavity 114 and the sixth cavity 115, and the constant difference pressure reducing valve 1 is fully opened; when the flow of the constant difference pressure reducing valve 1 is greater than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is greater than the pressure difference between the fifth cavity 114 and the sixth cavity 115, and the first valve core 12 starts to move downward, the opening degree of the constant difference pressure reducing valve 1 decreases, and the flow decreases, until the flow is equal to the set value(the pressure difference between the third cavity 112 and the fourth cavity 113 is equal to the pressure difference between the fifth cavity 114 and the sixth cavity 115).

[0070] When the pressure difference between the inlet A2 and the outlet B2 of the two-way cartridge valve 2 is constant, and the opening of the two-way cartridge valve 2 is constant, the flow through the two-way cartridge valve 2 is constant, so adjusting the opening of the two-way cartridge valve 2 can adjust the system flow; the first spring 33 has low requirements in this embodiment, only a small force is needed for resetting; at the same time, only the flow of the proportional speed regulating valve 31 needs to be adjusted to control the large flow, which is easier to achieve.

[0071] Embodiment four

[0072] When the first spring 33 and the second spring 131 do not meet the use conditions (the second spring 131 provides a pressure of <7bar when matched with the 120mm diameter differential pressure reducing valve; the first spring 33 provides a pressure of <7bar when matched with the 120mm diameter two-way cartridge valve 2), the flow of the two-way cartridge valve 2 is adjusted by two control oils.

[0073] As shown in Figure 8 the main oil path is communicated with the inlet A1 of the differential pressure reducing valve 1, the outlet B1 of the differential pressure reducing valve 1 is communicated with the inlet A2 of the two-way cartridge valve 2 and the fourth chamber 113 of the differential pressure reducing valve 1, and the outlet B2 of the two-way cartridge valve 2 is communicated with the actuator 4 and the third chamber 112 of the differential pressure reducing valve 1. The second control oil path is communicated with the inlet A6 of the first overflow valve 35 and the first chamber 212 of the two-way cartridge valve 2, and the outlet B6 of the first overflow valve 35 is communicated with the second chamber 213 of the two-way cartridge valve 2 and the oil tank 5. The third control oil path is communicated with the fifth chamber 114 of the differential pressure reducing valve 1 and the inlet A5 of the second overflow valve 132, and the outlet B5 of the second overflow valve 132 is communicated with the sixth chamber 115 of the differential pressure reducing valve 1 and the oil tank 5. The push rod 36 is rigidly connected to the second valve core 22 and the pressure adjusting spring of the first overflow valve 35 at both ends.

[0074] In the initial state, the main oil path and the second control oil path have no pressure oil, and the third control oil path has pressure oil. The third control oil path has a given control oil P4, and the pressure of the control oil P4 is determined by the second overflow valve 132 and does not change after being set. The differential pressure reducing valve 1 is fully open under the action of the control oil P4. The second valve core 22 of the two-way cartridge valve 2 is closed under the action of the first spring 33, and the first spring 33 only overcomes the friction force of the second valve core 22 to move.

[0075] When the main oil path provides pressure oil P1, since the differential pressure reducing valve 1 is in an open state in the initial state, the fourth chamber 113 is communicated with B1 and A1, and pressure oil enters the fourth chamber 113. The first valve core 12 is closed under the action of the pressure oil in the fourth chamber 113. The first chamber 212 and the second chamber 213 of the two-way cartridge valve 2 have a pressure of 0, and the two-way cartridge valve 2 remains closed.

[0076] When the flow of the two-way cartridge valve 2 needs to be adjusted, the opening degree adjustment process of the two-way cartridge valve 2 valve port: the second control oil way gives the control oil P3, at this time the flow direction of the control oil P3 is A6 (the first cavity 212)-B6-the second cavity 213-oil tank 5, the structure of the first overflow valve 35 is similar to that of the pump power valve, the pressure regulating spring of the first overflow valve 35 is connected with the push rod 36, the pressure regulating spring of the first overflow valve 35 is manually adjusted, the pressure of the first overflow valve 35 is set, the pressure of the first cavity 212 rises, the second spool 22 moves towards the second cavity 213, driving the push rod 36 to release the pressure regulating spring of the first overflow valve 35, as the second spool 22 displaces upwards, the compression amount of the pressure regulating spring of the first overflow valve 35 becomes smaller and smaller, the pressure of the first cavity 212 becomes smaller and smaller, when the displacement of the second spool 22 is equal to the compression amount of the pressure regulating spring of the first overflow valve 35, the pressure of the first cavity 212 is 0, the pressure of the first cavity 212 is equal to that of the second cavity 213, the second spool 22 stops moving and remains stable, at this time the opening degree of the second spool 22 and the second valve body 21 is certain.

[0077] Adjusting the compression amount of the pressure regulating spring of the first overflow valve 35→the pressure of the first cavity 212 is different→the displacement of the second spool 22 is different→the pressure of the second cavity 213 is consistent with that of the first cavity 212→the opening degree of the two-way cartridge valve 2 is different.

[0078] After the second spool 22 is opened, A2 and B2 are communicated, and since there is no pressure oil flowing at this time, the pressures at A2 and B2 are equal, that is, the pressures of the third cavity 112 and the fourth cavity 113 of the first spool 12 are equal, the first spool 12 is opened under the action of the pressure difference between the fifth cavity 114 and the sixth cavity 115, and the overall main oil way is: pressure oil P1-A1-B1-A2-B2-executive element, and the first spool 12 starts to automatically adjust the opening degree to match the corresponding flow.

[0079] The adjustment process of the constant differential pressure valve 1: the pressure of the fourth cavity 113 is equal to that of the two-way cartridge valve 2 inlet A2, the pressure of the third cavity 112 is equal to that of the two-way cartridge valve 2 outlet B2, and the pressure difference between the third cavity 112 and the fourth cavity 113 is equal to that between the two-way cartridge valve 2 inlet A2 and outlet B2, when the flow of the constant differential pressure valve 1 is less than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is less than that between the fifth cavity 114 and the sixth cavity 115, and the constant differential pressure valve 1 is fully opened; when the flow of the constant differential pressure valve 1 is greater than the set value, the pressure difference between the third cavity 112 and the fourth cavity 113 is greater than that between the fifth cavity 114 and the sixth cavity 115, the first spool 12 starts to move downwards, the opening degree of the constant differential pressure valve 1 decreases, and the flow decreases, until the flow is equal to the set value (the pressure difference between the third cavity 112 and the fourth cavity 113 is equal to that between the fifth cavity 114 and the sixth cavity 115).

[0080] When the pressure difference of the oil outlet of the two-way cartridge valve 2 is certain, and the opening of the two-way cartridge valve 2 is certain, the flow through the two-way cartridge valve 2 is certain, so that the opening of the two-way cartridge valve 2 is adjusted, and the system flow is adjusted; only the deformation amount of the pressure regulating spring of the first overflow valve 35 needs to be manually adjusted, so that the control of the large flow is realized, one-way control oil can be reduced, the adaptability is high, and the flow requirement of the control oil is low.

[0081] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A large flow hydraulic control system characterized in that, it comprises a constant differential pressure reducing valve (1) for automatically compensating load changes, a two-way cartridge valve (2) in communication with the constant differential pressure reducing valve (1), a second control mechanism (3) for adjusting the opening of the two-way cartridge valve (2), and an actuator (4) in communication with the oil outlet of the two-way cartridge valve (2), the two-way cartridge valve (2) comprises a second valve body (21) and a second spool (22) slidingly embedded in the second valve body (21), the second valve body (21) comprises a second control cavity and a second throttling cavity (211), a second protruding ring (221) is arranged on the second spool (22), the second protruding ring (221) separates the second control cavity into a first cavity (212) and a second cavity (213), the oil inlet of the second throttling cavity (211) is in communication with the oil outlet of the constant differential pressure reducing valve (1), the oil outlet of the second throttling cavity (211) is in communication with the actuator (4), the pressure difference between the first cavity (212) and the second cavity (213) is adjusted by the control oil introduced by the second control mechanism (3), so as to adjust the opening of the two-way cartridge valve (2), the constant differential pressure reducing valve (1) comprises a first valve body (11), a first spool (12), and a first control mechanism (13) for adjusting the preset differential pressure of the constant differential pressure reducing valve (1), the first valve body (11) comprises a first control cavity and a first throttling cavity (111), a first protruding ring (121) is arranged on the first spool (12), the first protruding ring (121) separates the first control cavity into a third cavity (112) and a fourth cavity (113), the third cavity (112) is in communication with the oil outlet of the second throttling cavity (211), the oil inlet of the first throttling cavity (111) is in communication with the main oil circuit, the oil outlet of the first throttling cavity (111) is in communication with the oil inlet of the second throttling cavity (211) and the fourth cavity (113), the first control mechanism (13) adjusts the opening of the constant differential pressure reducing valve (1) by adjusting the pressure difference between the third cavity (112) and the fourth cavity (113); the second control mechanism (3) comprises a proportional speed regulating valve (31), a damping hole (32), a first spring (33), a first overflow valve (35), and a push rod (36), the oil inlet of the proportional speed regulating valve (31) is in communication with the first control oil circuit, the oil outlet of the proportional speed regulating valve (31) is in communication with the oil inlet of the damping hole (32) and the first cavity (212), the oil outlet of the damping hole (32) is in communication with the oil outlet of the first overflow valve (35) and the oil tank (5), the oil inlet of the first overflow valve (35) is in communication with the second control oil circuit and the second cavity (213), the two ends of the first spring (33) are connected with the second valve body (21) and the second spool (22) respectively to drive the second spool (22) to reset, the pressure adjusting spring of the first overflow valve (35) is connected with the second spool (22) through the push rod (36). Alternatively, the second control mechanism (3) comprises a first spring (33), a first overflow valve (35) and a push rod (36), two ends of the first spring (33) are connected with the second valve body (21) and the second spool (22) respectively to drive the second spool (22) to reset, an oil inlet of the first overflow valve (35) is communicated with the second control oil passage and the first cavity (212), an oil outlet of the first overflow valve (35) is communicated with the second cavity (213) and the oil tank (5), a pressure regulating spring of the first overflow valve (35) is connected with the push rod (36), the pressure of the first overflow valve (35) is set by manually adjusting the pressure regulating spring of the first overflow valve (35), the pressure of the first cavity (212) is increased to push the second spool (22) to move towards the second cavity (213), the push rod (36) is driven to release the pressure regulating spring of the first overflow valve (35), as the second spool (22) is displaced upwards, the pressure regulating spring of the first overflow valve (35) is compressed less and less, and the pressure of the first cavity (212) is smaller and smaller.

2. The high-flow hydraulic control system according to claim 1, wherein the first control mechanism (13) comprises a second spring (131) for driving the first spool (12) to reset, the second spring (131) is arranged in the third cavity (112), and two ends of the second spring (131) are connected with the first valve body (11) and the first spool (12) respectively.

3. The high-flow hydraulic control system according to claim 1, wherein the first valve body (11) further comprises a third control cavity, the first spool (12) is provided with a third protruding ring (122), the third protruding ring (122) divides the third control cavity into a fifth cavity (114) and a sixth cavity (115), and the first control mechanism (13) comprises a second overflow valve (132), an oil inlet of the second overflow valve (132) is communicated with the third control oil passage and the fifth cavity (114), and an oil outlet of the second overflow valve (132) is communicated with the sixth cavity (115) and the oil tank (5).

4. The high-flow hydraulic control system according to claim 3, wherein the first valve body (11) and the second valve body (21) are vertically arranged, the first cavity (212) is arranged below the second cavity (213), the third cavity (112) is arranged below the fourth cavity (113), and the fifth cavity (114) is arranged below the sixth cavity (115).

5. The high-flow hydraulic control system according to claim 3 or 4, wherein the two circular ring end faces of the second protruding ring (221) are equal in area, the two circular ring end faces of the first protruding ring (121) are equal in area, and the two circular ring end faces of the third protruding ring (122) are equal in area.

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