Stacked fixed differential pressure reducing valve

Abstract

The stacked type fixed differential pressure reducing valve comprises a valve body, a valve element arranged in the valve body in a sliding mode and a shuttle valve arranged at one end of the valve body, a left valve cavity is formed between one end of the valve element and the valve body, a right valve cavity spaced from the left valve cavity is formed between the middle of the valve element and the valve body, and a large-aperture oil supply channel P penetrating through the right valve cavity is formed in the valve body; the valve body is provided with a first load port A and a second load port B, the first load port A and the second load port B are communicated with the left valve cavity through the shuttle valve, and the valve element is provided with a damping structure so that the valve element can slide in the valve body in a damping mode. The large-aperture oil supply channel P is arranged, so that the device is suitable for the large-flow condition; the valve element is provided with the damping structure so that the valve element can slide in the valve body in a damping mode, the stability and precision of the pressure reducing valve can be improved, the fixed differential pressure reducing valve can move slowly even under the high pressure condition, the stability under the high pressure is further improved, and the fixed differential pressure reducing valve is suitable for the working condition of high flow.

Description

Technical Field

[0001] The invention relates to the technical field of valves, and in particular to a differential pressure reducing valve. Background Art

[0002] The pressure reducing valve is a valve that reduces the inlet pressure to a certain required outlet pressure through regulation, and automatically maintains a stable outlet pressure by relying on the energy of the medium itself. From the perspective of fluid mechanics, the pressure reducing valve is a throttling element with variable local resistance, that is, by changing the throttling area, the flow rate and the kinetic energy of the fluid are changed, resulting in different pressure losses, thereby achieving the purpose of reducing pressure. Then, by relying on the regulation of the control and regulation system, the fluctuation of the pressure behind the valve is balanced with the spring force, so that the pressure behind the valve remains constant within a certain error range.

[0003] At present, the maximum working pressure of domestic large flow differential pressure reducing valves is 31.5Mpa at P port, 15MPa at T port, 21MPa at AB port, and the maximum flow is 80L / min. Therefore, there is a technical gap for high pressure and large flow pressure reducing valves.

[0004] The Chinese invention patent with the publication date of 2018-11-16 and the publication number of CN108825835A discloses a direct-acting superimposed pressure reducing valve, which includes: a valve body, a valve core assembled in the inner cavity of the valve body, a steel ball, a spring seat, a pressure regulating spring, a pressure regulating plunger, a pressure regulating screw, and a front cover fixed to the front end of the valve body, wherein the front cover is provided with a first through hole for installing the pressure regulating screw, and a second through hole for installing the pressure regulating plunger and the pressure regulating spring, wherein the pressure regulating screw and the pressure regulating plunger are connected in a floating split manner, which solves the problem of being unable to adjust the pressure or difficult to adjust the pressure due to the coaxiality difference; in addition, through the use of positive and negative threads, when the positive thread rotates counterclockwise to reduce the pressure, the negative thread part of the pressure regulating screw will not be screwed out, but the pressure regulating screw forces the pressure regulating plunger to move to the right, thereby reducing the pressure to the specified minimum pressure value. However, this patent is not suitable for high pressure and large flow.

[0005] The Chinese utility model patent with the publication date of January 28, 2008 and the publication number of CN201184438Y discloses a superimposed pressure reducing valve, including a valve block and a valve core, characterized in that the valve core is composed of a plug-in valve core. The plug-in valve core includes: an A valve core in the first chamber, an A spring connected to push the A valve core, and an A spring chamber accommodating the A spring; a lifting valve core in the second chamber, a B spring connected to push the lifting valve core, a B spring chamber accommodating the B spring, and an adjusting slider provided with the B spring chamber; an adjusting bolt hole is provided at one end of the adjusting slider, and an adjusting bolt is installed in the adjusting bolt hole; a throttle port is connected between the first chamber and the second chamber. The patent has the following characteristics: 1. The plug-in pressure reducing valve is a standardized product, which is easy to select and purchase; 2. According to the actual conditions on site, different sizes of connecting blocks are processed, and the interchangeability with the on-site hydraulic valve is good; 3. The plug-in assembly has strong anti-pollution ability and the life of the valve parts is improved; 4. The system is stable and reliable. However, the patent is not suitable for high pressure and large flow. Summary of the invention

[0006] In view of the above technical problems, the present invention proposes a stacked differential pressure reducing valve to solve the problem that there is a lack of pressure reducing valves suitable for high pressure and large flow in the prior art.

[0007] In order to achieve the above object, the technical solution of the present invention is achieved as follows: A superimposed differential pressure reducing valve comprises a valve body, a valve core slidably arranged in the valve body and a shuttle valve arranged at one end of the valve body, a left valve cavity is formed between one end of the valve core and the valve body, a right valve cavity spaced from the left valve cavity is formed between the middle of the valve core and the valve body, a large-aperture oil supply passage P passing through the right valve cavity is provided on the valve body; a first load port A and a second load port B are provided on the valve body, the first load port A and the second load port B are connected to the left valve cavity through the shuttle valve so that the fluid of one of the first load port A and the second load port B enters the left valve cavity to push the movement of the valve core for changing the opening between the right valve cavity and the large-aperture oil supply passage P, and a damping structure is provided on the valve core so that the valve core slides damped in the valve body. The present invention provides a large-aperture oil supply channel P, so that the device is suitable for large flow conditions; a damping structure is provided on the outer side of the valve core to damp the sliding of the valve core in the valve body, which not only improves the stability and accuracy of the pressure reducing valve, but also enables the differential pressure reducing valve to move slowly even under high pressure conditions, further improving the stability under high pressure, so that the differential pressure reducing valve is suitable for working conditions with high flow and high pressure.

[0008] Furthermore, in order to select the load port with higher pressure between the first load port A and the second load port B through the shuttle valve to supply fluid into the left valve chamber, the first load port A and the second load port B are respectively connected to two inlet channels of the shuttle valve, and the outlet channel of the shuttle valve is connected to the left valve chamber.

[0009] Furthermore, in order to allow the valve core to be reset or moved under the action of the spring, one end of the valve core is in contact with the shuttle valve through the spring, so that the left valve chamber is formed between the valve core, the shuttle valve and the valve body.

[0010] Furthermore, in order to introduce a higher pressure fluid into the left valve chamber through the shuttle valve, a first load channel is provided in the valve body for connecting the first load port A with one of the inlet channels of the shuttle valve, and a second load channel is provided in the valve body for connecting the second load port B with another inlet channel of the shuttle valve.

[0011] Furthermore, in order to seal the outer ends of the inlet and outlet and allow the fluid to flow from the inside of the shuttle valve into the left valve chamber, the middle part of the outlet channel of the shuttle valve is connected to the left valve chamber through a through hole, and the shuttle valve is also provided with a valve cover plug for sealing the lower end of the outlet channel, and the shuttle valve is provided with a valve body side plug for sealing the outer end of the inlet channel.

[0012] Furthermore, in order to slow down the flow rate of the fluid, the through hole is a damping hole 1, and a damping hole 2 is provided inside the valve core.

[0013] Furthermore, in order to control the oil output of the large-aperture oil supply channel according to the magnitude of the thrust exerted on the valve core, the large-aperture oil supply channel P includes an oil inlet channel communicating with one end of the right valve chamber and an oil outlet channel communicating with the other end of the right valve chamber. A conical surface is provided at the portion of the valve core corresponding to the oil outlet channel to form a small valve port between the right valve chamber and the oil outlet channel. The movement of the valve core can control the opening of the small valve port.

[0014] Furthermore, in order to achieve the function of oil return, the valve body is also provided with an oil return channel T communicating with one side of the valve core.

[0015] Furthermore, in order to use a large-aperture return channel to perform an oil return function, an oil return chamber is provided between the valve core and the valve body, the oil return chamber intersects and communicates with one side of the oil return channel T, and the oil return chamber is located between the left valve chamber and the right valve chamber.

[0016] Furthermore, in order to enable the differential pressure reducing valve to be used in conjunction with a pilot proportional valve, a pilot control oil inlet X and a pilot control oil return port Y for cooperating with the pilot proportional valve are further provided on the valve body.

[0017] Beneficial effects of the present invention: 1. The present invention sets a shuttle valve, through which the higher pressure of the first load port A or the second load port B is selected as the feedback oil to be passed into the left valve chamber of the differential pressure reducing valve, and at the same time, the oil coming from the large-aperture oil supply channel passes through the valve body and the valve core to reach the right valve chamber, and the movement of the valve core makes the oil in the two chambers form an axial force balance; 2. The present invention divides the large-aperture oil supply channel into an oil inlet channel and an oil outlet channel by staggering the large-aperture oil supply channel at the valve core, and the oil inlet channel and the oil outlet channel are respectively connected to different parts of the right valve cavity, so that the amount of oil entering the oil outlet channel can be controlled by moving the valve core; 3. The present invention provides a conical surface with a small taper at the position corresponding to the oil outlet passage outside the valve core, so that the valve core and the valve body form a small valve port at the entrance of the right valve chamber leading to the oil outlet passage, so that the opening of the small valve port can be controlled by the movement of the valve core, thereby controlling the amount of oil entering the oil outlet passage; 4. The present invention provides a large-diameter feedback port and a large-diameter oil return channel, so that the differential pressure reducing valve can be used in large-flow conditions; 5. The present invention provides a damping structure on the valve core to damp the sliding of the valve core in the valve body, which not only improves the stability and accuracy of the pressure reducing valve, but also enables the differential pressure reducing valve to move slowly even under high pressure, further improving the stability under high pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the appearance structure of the present invention; Figure 2 It is a schematic diagram of the transverse cross-sectional structure of the present invention; Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure of FF; Figure 4 for Figure 1 Schematic diagram of the cross-sectional structure of the CC; Figure 5 for Figure 3 Schematic diagram of the cross-sectional structure of DD; Figure 6 for Figure 3 Schematic diagram of the cross-sectional structure of EE; Figure 7 It is the hydraulic principle diagram of the present invention; Figure 8 It is the pressure flow curve diagram of the present invention.

[0020] Reference numerals in the figures: 1. Valve body, 2. Shuttle valve, 3. Shuttle valve seat, 4. Left valve chamber, 5. Right valve chamber, 6. Valve core, 7. First load channel, 8. Return spring, 9. Valve body plug, 10. Shuttle valve plug, 11. Valve cover plug, 12. Valve cover orifice, 13. Second load channel, 14. Hexagon socket head screw, 15. Through hole, 16. O-ring, 17. Oil return chamber, 18. Small valve port, 19. Damping hole 2, P, large-aperture oil supply channel, Pa, oil supply outlet, P b , oil supply inlet, T, oil return channel, Ta, oil return inlet, T b , oil return port, X, pilot control oil inlet, Y, pilot control oil return port, A, first load port, B, second load port. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] like Figure 1 As shown, a superimposed differential pressure reducing valve described in Example 1 of the present invention includes a valve body 1, a valve core 6 slidably disposed in the valve body 1, and a shuttle valve 2 disposed at one end of the valve body 1, and the valve body 1 and the shuttle valve 2 are detachably connected and fixed. In this embodiment, the valve body 1 is detachably connected and fixed to the shuttle valve 2 by a hexagon socket cylindrical head screw 14, and other connection methods may be adopted in other embodiments. A left valve chamber 4 is formed between one end of the valve core 6 and the valve body 1, and a right valve chamber 5 is formed between the middle part of the valve core 6 and the valve body 1, and the left valve chamber 4 and the right valve chamber 5 are separated and not connected. A large-aperture oil supply channel P passing through the right valve chamber 5 is provided on the valve body 1, and the large-aperture oil supply channel P includes an oil inlet channel communicating with one end of the right valve chamber 5 and an oil outlet channel communicating with another position of the right valve chamber 5, that is, the large-aperture oil supply channel P is disconnected into upper and lower parts at the valve core 6. The oil inlet channel is located on the lower side of the valve core 6, and the oil outlet channel is located on the upper side of the valve core. As shown Figure 2 As shown, the oil inlet channel and the oil outlet channel are respectively connected to different parts of the right valve chamber 5, and the right valve chamber 5 is located on the side of the left valve chamber 4 away from the shuttle valve. The valve body 1 is provided with a first load port A and a second load port B connected to the left valve chamber 4, and the first load port A and the second load port B are connected to the left valve chamber 4 through the shuttle valve 2. The shuttle valve selects the load port with higher pressure among the first load port A and the second load port B as the feedback port to supply fluid into the left valve chamber. The fluid in the left valve chamber is continuously increased to promote the movement of the valve core 6, thereby changing the opening between the right valve chamber 5 and the large-aperture oil supply channel P, so that the differential pressure reducing valve is suitable for large flow conditions.

[0023] Furthermore, if Figure 2 and Figure 4 As shown, a damping structure is provided on the valve core 6 to damp the sliding of the valve core 6 in the valve body 1, so that the differential pressure reducing valve can move slowly even under high pressure, further improving the stability under high pressure, making the differential pressure reducing valve suitable for large flow and high pressure working conditions.

[0024] Furthermore, if Figure 2 and Figure 4 As shown, the valve core 6 is provided with a reduced diameter section at the corresponding position corresponding to the right valve cavity 5, that is, the diameter of this position is smaller than the diameter of the valve core body at other positions of the valve core 6, so that a right valve cavity with a larger volume is formed between the reduced diameter section and the valve body 1, so that a large flow of oil can enter and exit the right valve cavity 5 through the large-diameter oil supply channel P.

[0025] Furthermore, a step hole coaxial with the valve core 6 and with a larger aperture is provided at the right end of the right valve chamber 5 and the portion corresponding to the oil outlet passage, and the right valve chamber 5 is connected to the oil outlet passage through the step hole. A conical surface is provided at the portion corresponding to the oil outlet passage on the valve core 6, so that a small valve port 18 is formed between the right valve chamber 5 and the oil outlet passage, that is, a valve port is formed between one side of the step hole and the conical surface of the valve core 6, the small end of the conical surface faces the left valve chamber 4, and the small end of the conical surface is connected to the reduced diameter section of the valve core, and the large end of the conical surface is smoothly connected to the valve core body. And the conical surface is a conical surface with a smaller taper, so that the valve port is a small valve port 18. The shuttle valve selects the load port with higher pressure among the first load port A and the second load port B as the feedback port to supply fluid into the left valve chamber 4, pushes the movement of the valve core 6, thereby controlling the opening of the small valve port 18, and thus changing the flow of the oil outlet passage. There is a steep slope or radial plane between the end of the reduced diameter section and the valve core body, and the oil entering the right valve chamber 5 through the large diameter oil supply channel P will also push the valve core 6 to move through the steep slope when there is a pressure difference with the left valve chamber 4. When the oil entering the oil inlet channel pushes the valve core 6 to move to the right, the opening of the small valve port 18 increases.

[0026] Furthermore, the surface where the small end of the conical surface meets the reduced diameter section of the valve core, i.e., the end surface of the small end of the conical surface, is not a plane perpendicular to the valve core, but an inwardly concave frustum surface. The outer circumference of the reduced diameter section extends to the top of the frustum surface of the conical surface in a direction parallel to the axis, and the outer circumference of the reduced diameter section and the frustum surface are connected by a rounded transition.

[0027] The first load port A and the second load port B are respectively connected to the two inlet channels of the shuttle valve 2, and the outlet channel of the shuttle valve 2 is connected to the left valve chamber 4. Figure 3As shown, a shuttle valve seat 3 is provided in the shuttle valve 2, and two inlet channels are communicated through the shuttle valve seat 3, and the shuttle valve seat 3 is communicated with the outlet channel of the shuttle valve 2. A piston is provided in the shuttle valve seat 3, and when the pressure of one of the first load port A and the second load port B is higher, the passage between the inlet channel and the outlet channel corresponding to the load port will be opened by the movement of the piston, and the passage between the inlet channel and the outlet channel corresponding to the other load port will be closed, so that the fluid of the higher pressure load port enters the left valve chamber 4. The first load port A and the second load port B are large-diameter load ports.

[0028] Embodiment 2 is different from Embodiment 1 in that Figure 5 and Figure 6 As shown, the valve body 1 is provided with a first load channel 7 for connecting the first load port A with one of the inlet channels of the shuttle valve 2, and the valve body 1 is provided with a second load channel 13 for connecting the second load port B with the other inlet channel of the shuttle valve 2. The first load channel 7 and the second load channel 13 are both small-diameter channels.

[0029] Embodiment 3 is different from Embodiment 1 in that Figure 2 and Figure 4 As shown, one end of the valve core 6 is abutted against the shuttle valve 2 through the spring 8. Specifically, the end of the valve core 6 is provided with a spring limiting groove coaxial with the valve core axis, the spring 8 is arranged in the spring limiting groove, and one end of the spring 8 is abutted against the side of the shuttle valve 2 after passing through the spring limiting groove, so that the left valve chamber 4 is formed between the valve core 6 and the shuttle valve 2 and the valve body 1. The middle part of the outlet channel of the shuttle valve 2 is connected to the left valve chamber 4 through a through hole. In this embodiment, the damping structure includes a through hole 15, that is, the through hole 15 is a damping hole 1, which can slow down the flow of the fluid. In addition, the damping structure also includes a damping hole 2 19, as shown Figure 4 As shown, the damping hole 2 19 is arranged at the right end of the valve core, so that the valve core can move with damping.

[0030] Furthermore, if Figure 3 As shown, the shuttle valve 2 is also provided with a valve cover plug 11 for blocking the lower end of the outlet channel, and the shuttle valve 2 is provided with a valve body side plug 10 for blocking the outer end of the inlet channel.

[0031] Embodiment 4 is different from Embodiment 1 in that Figure 1 and Figure 2 As shown, the valve body 1 is also provided with an oil return channel T communicating with one side of the valve core 6 .

[0032] Furthermore, if Figure 2 As shown, an oil return chamber 17 is provided between the valve core 6 and the valve body 1 , and the oil return chamber 17 intersects and communicates with one side of the oil return channel T. The oil return chamber 17 is located between the left valve chamber 4 and the right valve chamber 5 .

[0033] Embodiment 5 is different from Embodiment 1 in that Figure 1 and Figure 2 As shown, the valve body 1 is also provided with a pilot control oil inlet X and a pilot control oil return port Y for cooperating with the pilot proportional valve.

[0034] Embodiment 6 is different from Embodiment 5 in that the pressure reducing valve is divided into upper and lower end surfaces, the upper end surface is named a, and the lower end surface is named b. The large-aperture oil supply channel P is located at the opening of the lower end surface, i.e., the inlet of the oil inlet channel, which is the oil inlet of the large-aperture oil supply channel P, i.e., the oil supply inlet P. b The port of the large-aperture oil supply channel P located at the upper end surface is the outlet of the oil outlet channel, which is the oil outlet of the large-aperture oil supply channel P, i.e., the oil supply outlet is indicated by Pa; the T channel is the oil return channel, the port of the oil return channel located at the upper end surface is the oil inlet of the oil return channel, i.e., the oil return inlet is indicated by Ta, and the port of the oil return channel located at the lower end surface is the oil outlet of the oil return channel, i.e., the oil return outlet is indicated by T b A represents the first load port, and the port of the first load port located on the upper end surface is the oil inlet of the first load port, that is, the first load inlet is represented by Aa. B represents the second load port, and the port of the second load port located on the upper end surface is the oil inlet of the second load port, that is, the second load inlet is represented by Ba.

[0035] Embodiment 7, the main working principle of the superimposed differential pressure reducing valve is as follows: When the product is working, the oil inlet from the large-aperture oil supply channel P is the oil supply inlet P. bHigh-pressure oil is introduced, and the oil passes through the valve body 1 and the valve core 6 to reach the right valve chamber 5 between the valve core 6 and the valve body 1 in the pressure reducing valve. At the same time, the shuttle valve 2 selects the one with higher pressure, the first load port A or the second load port B, as the feedback port, and the oil in the feedback port passes through the corresponding first load channel 7 or the second load channel 13 to enter the left valve chamber 4 between the valve core 6 and the valve body 1 in the pressure reducing valve. That is, after the oil in the load port with higher pressure, the first load port A and the second load port B, enters the shuttle valve 2, the piston in the shuttle valve 2 moves so that the load port can communicate with the left valve chamber 4 through the shuttle valve 2, and the oil in the load port smoothly enters the left valve chamber 4 through the shuttle valve 2; while the movement of the piston causes the other load port to be unable to communicate with the left valve chamber 4 through the shuttle valve 2, and the load port is closed, so that the oil in it cannot enter the left valve chamber 4. The oil in the two valve chambers, i.e. the left valve chamber 4 and the right valve chamber 5, forms an axial force balance through the reset spring 8, i.e. the pressure at the oil supply outlet Pa is equal to the sum of the pressure at the feedback port and the spring force, and the spring force remains unchanged, i.e. the pressure at the oil supply outlet Pa and the feedback pressure difference remain unchanged. When Pa→Aa, i.e. the pressure difference between the oil supply outlet Pa and the first load inlet Aa, or Pa→Ba, i.e. the pressure difference between the oil supply outlet Pa and the second load inlet Ba is less than 1MPa, the reset spring 8 keeps the valve core 6 in the fully open position from the oil supply inlet Pb to the oil supply outlet Pa. At this time, the pressure reducing valve does not work, and the system functions as a throttle valve; when the pressure difference is greater than 1MPa, P b The oil entering the port pushes the valve core 6, the valve port opening decreases, and the Pa port pressure drops until the pressure difference reaches 1MPa and reaches a balanced state.

[0036] The rest is the same as Example 6.

[0037] Example 8: The stacked differential pressure reducing valve of the present invention can also be stacked with a pilot proportional valve (not shown in the figure) when in use.

[0038] In addition to the large-aperture oil supply channel P, the oil return channel T, the first load port A and the second load port B, the valve body 1 is also provided with a pilot control oil inlet X and a pilot control oil return port Y for the pilot-operated proportional valve. Figure 1 There are two oil supply methods. If internal oil supply is selected, the oil is drawn from the large-aperture oil supply channel P to the pressure oil of the pilot control oil inlet X. If external oil supply is selected, an independent oil circuit is required to supply oil to the pilot control oil inlet X. Figure 7 This is the hydraulic principle diagram.

[0039] When the system enters the working state, the function of the superimposed differential pressure reducing valve of the present invention is to keep the pressure difference at both ends of the inlet and outlet of the pilot proportional valve roughly constant. If the interference of the hydraulic force is not considered, this constant is equivalent to the spring force of the return spring 8 (the pressure converted from the pre-compression amount). The flow rate through the valve is set by adjusting the opening of the pilot proportional valve, that is, the change of the load pressure will not affect the set flow rate.

[0040] Figure 8 This is the pressure flow curve after the pressure reducing valve and the pilot proportional valve are superimposed in this embodiment. As the pilot proportional valve opening command signal gradually increases, when the flow rate reaches 325L / min, the pressure difference reaches about 24bar. When the pilot proportional valve opening reaches 100%, the pressure difference is 1MPa, that is, the pressure difference of the pressure reducing valve 1 is 2.4MPa (24bar) -1MPa = 1.4MPa. Thus, the pressure reducing effect for high pressure and large flow is achieved.

[0041] The rest is the same as Example 7.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that any modification to the technical solutions described in the aforementioned embodiments, or any equivalent replacement of some or all of the technical features therein, within the spirit and principles of the present invention, and such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A superimposed differential pressure reducing valve, characterized in that: The invention comprises a valve body (1), a valve core (6) slidably arranged in the valve body (1), and a shuttle valve (2) arranged at one end of the valve body (1); a left valve cavity (4) is formed between one end of the valve core (6) and the valve body (1); a right valve cavity (5) spaced from the left valve cavity (4) is formed between the middle of the valve core (6) and the valve body (1); a large-aperture oil supply passage (P) passing through the right valve cavity (5) is provided on the valve body (1); a first load port (A) and a second load port (B) are provided on the valve body (1); the first load port (A) and the second load port (B) are connected to the left valve cavity (4) through the shuttle valve (2) so that fluid in one of the first load port (A) and the second load port (B) enters the left valve cavity (4) to push the movement of the valve core (6) to change the opening between the right valve cavity (5) and the large-aperture oil supply passage (P); and a damping structure is provided on the valve core (6) to damp the sliding of the valve core (6) in the valve body (1).

2. The stacked differential pressure reducing valve according to claim 1, characterized in that: The first load port (A) and the second load port (B) are respectively connected to two inlet channels of the shuttle valve (2), and the outlet channel of the shuttle valve (2) is connected to the left valve chamber (4).

3. The stacked differential pressure reducing valve according to claim 2, characterized in that: One end of the valve core (6) is in contact with the shuttle valve (2) via a spring (8), so that the left valve chamber (4) is formed between the valve core (6), the shuttle valve (2) and the valve body (1).

4. The stacked differential pressure reducing valve according to claim 3, characterized in that: The valve body (1) is provided with a first load channel (7) for connecting the first load port (A) with one of the inlet channels of the shuttle valve (2), and the valve body (1) is provided with a second load channel (13) for connecting the second load port (B) with the other inlet channel of the shuttle valve (2).

5. The stacked differential pressure reducing valve according to claim 3 or 4, characterized in that: The middle of the outlet channel of the shuttle valve (2) is communicated with the left valve chamber (4) via a through hole (15); the shuttle valve (2) is also provided with a valve cover plug (11) for blocking the lower end of the outlet channel; and the shuttle valve (2) is provided with a valve body side plug (10) for blocking the outer end of the inlet channel.

6. The stacked differential pressure reducing valve according to claim 5, characterized in that: The through hole (15) is a damping hole 1, and a damping hole 2 (19) is provided inside the valve core (6).

7. The stacked differential pressure reducing valve according to any one of claims 1 to 4 and 6, characterized in that: The large-aperture oil supply passage (P) comprises an oil inlet passage communicating with one end of the right valve chamber (5) and an oil outlet passage communicating with the other end of the right valve chamber (5); a conical surface is provided on the valve core (6) at a position corresponding to the oil outlet passage so as to form a small valve port (18) between the right valve chamber (5) and the oil outlet passage; the movement of the valve core (6) can control the opening of the small valve port (18).

8. The stacked differential pressure reducing valve according to any one of claims 1 to 4 and 6, characterized in that: The valve body (1) is also provided with an oil return passage (T) communicating with one side of the valve core (6).

9. The stacked differential pressure reducing valve according to claim 8, characterized in that: An oil return chamber (17) is provided between the valve core (6) and the valve body (1), the oil return chamber (17) intersects and communicates with one side of the oil return channel (T), and the oil return chamber (17) is located between the left valve chamber (4) and the right valve chamber (5).

10. The stacked differential pressure reducing valve according to any one of claims 1 to 4, 6 and 9, characterized in that: The valve body (1) is also provided with a pilot control oil inlet (X) and a pilot control oil return port (Y) for cooperating with the pilot proportional valve.

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