CN218000485U - Pilot-operated electromagnetic valve - Google Patents

Abstract

The utility model provides a pilot operated solenoid valve, include: the valve cover structure is provided with a pilot valve cavity and a communication channel; the pilot valve core is movably arranged in the pilot valve cavity and is in limit fit with the inner wall of the pilot valve cavity; the valve seat structure is connected with the valve cover structure, a surrounding area between the valve cover structure and the valve seat structure forms a main valve cavity, and the main valve cavity is communicated with the pilot valve cavity through a communicating channel. By adopting the scheme, the communication between the pilot valve cavity and the main valve cavity is realized through the communication channel, the pressure balance between the pilot valve cavity and the main valve cavity is ensured in the process that the pilot valve core moves in the pilot valve cavity, the situation that the pilot valve core is difficult to move due to the large pressure difference between the pilot valve cavity and the main valve cavity is prevented, and meanwhile, the communication channel is directly arranged on the valve cover structure, so that the processing cost of the pilot electromagnetic valve is reduced.

Description

Pilot-operated electromagnetic valve

Technical Field

The utility model relates to a solenoid valve technical field particularly, relates to a pilot operated solenoid valve.

Background

At present, a pilot valve core in a pilot type electromagnetic valve is movably arranged in a pilot valve cavity and is in limit fit with part of the inner wall of the pilot valve cavity, and because the pilot valve core is generally susceptible to the influence of cavities on two sides of the pilot valve core, namely the pressure difference between the pilot valve cavity and a main valve cavity, the pilot valve core is difficult to move.

However, in such an arrangement, the exhaust component needs to be separately processed, and an assembly process of the exhaust component and the pilot valve chamber needs to be added, which increases a processing process and processing cost.

SUMMERY OF THE UTILITY MODEL

The utility model provides a pilot operated solenoid valve to lead to manufacturing procedure and the more problem of processing cost through exhaust part intercommunication pilot operated valve core and last valve chamber among the solution prior art.

In order to solve the above problem, the utility model provides a guide's formula solenoid valve, include: the valve cover structure is provided with a pilot valve cavity and a communication channel; the pilot valve core is movably arranged in the pilot valve cavity and is in limit fit with the inner wall of the pilot valve cavity; the valve seat structure is connected with the valve cover structure, a surrounding area between the valve cover structure and the valve seat structure forms a main valve cavity, and the main valve cavity is communicated with the pilot valve cavity through a communicating channel.

Further, the pilot valve cavity comprises a first cavity section and a second cavity section which are communicated with each other and are coaxial, the radial size of the second cavity section is smaller than that of the first cavity section, the pilot valve core is in limit fit with the inner wall of the second cavity section, an area between the inner side wall of the first cavity section and the outer side wall of the pilot valve core forms an annular cavity, and the communication channel is arranged on the valve cover structure and is respectively communicated with the annular cavity and the main valve cavity.

Furthermore, the first cavity section, the second cavity section and the main valve cavity are all cylindrical cavities, the first cavity section, the second cavity section and the main valve cavity are coaxial, the plurality of communication channels are arranged, and the plurality of communication channels are distributed at intervals along the circumferential direction of the second cavity section.

Further, the valve cover structure comprises an integrally formed annular plate, the annular plate is located in the pilot valve cavity, a second cavity section is formed in an area surrounded in the annular plate, and the communication channel penetrates through the annular plate, wherein the area of the communication channel on the radial section of the annular plate is smaller than or equal to the area of the solid structure of the annular plate in the radial direction.

Furthermore, the communication channel is arranged on the inner wall of the second cavity section and part of the inner wall of the first cavity section in a penetrating mode, and the extending direction of the communication channel is parallel to the axis of the second cavity section.

Further, the first cavity section comprises a first limiting section and a second limiting section which are communicated with each other, the second limiting section is communicated with the second cavity section, the radial size of the first limiting section is larger than that of the second limiting section, and a part of the communication channel penetrates through the inner wall of the second limiting section.

Further, the cross section of the communication channel in the radial direction of the second cavity section and the cross section of the communication channel in the radial direction of the second limit section are both arc-shaped, the arc radiuses of the two arc-shaped cross sections are the same and are overlapped in the axial direction of the second cavity section, the arc length of the arc-shaped cross section of the communication channel in the radial direction of the second cavity section is larger than that of the arc-shaped cross section of the communication channel in the radial direction of the second limit section, the length of the communication channel extending along the axial direction of the pilot valve cavity is L1, the axial length of the second cavity section is L2, the axial length of the second limit section is L3, and L2 is less than L1 and less than (L2 + L3).

Further, the cross section of the communication channel in the radial direction of the second cavity section and the cross section of the communication channel in the radial direction of the second limiting section are two coincided semi-circles with equal arc radiuses, the arc radiuses of the two semi-circles are both r1, the diameter of the second cavity section is D1, the diameter of the second limiting section is D2, and D2/2 < (r 1+ D1/2).

Further, the pilot-operated solenoid valve still includes drive structure, drive structure includes the sleeve pipe, move the iron core, quiet iron core and actuating lever, quiet iron core is located and moves between iron core and the pilot valve core and fixed the setting in the sleeve pipe, move the movably setting of iron core in the sleeve pipe, the one end of actuating lever with move the iron core and connect, the other end and the pilot valve core butt of actuating lever, sheathed tube one end is worn to establish in first spacing section and with the diapire butt of first spacing section, the spacing cooperation of sheathed tube outer wall and the inner wall of first spacing section.

Further, the pilot valve core includes the case main part and the elastic component that sets up around the case main part, the both ends of elastic component respectively with the diapire butt of the spacing section of case main part, second, the spacing cooperation of the outer peripheral face of elastic component and the inner wall of the spacing section of second.

The pilot electromagnetic valve further comprises a piston structure, the piston structure is arranged in the main valve cavity and divides the main valve cavity into an upper valve cavity and a lower valve cavity, the upper valve cavity is located in the valve cover structure, the lower valve cavity is located in the valve seat structure, the valve seat structure is provided with a first circulation channel and a second circulation channel, the first circulation channel is provided with a first valve port communicated with the lower valve cavity, the piston structure is provided with a second valve port communicated with the upper valve cavity and the lower valve cavity, the second circulation channel is communicated with the lower valve cavity, the piston structure can be arranged in the lower valve cavity in an arched mode to block or open the first valve port, and the pilot valve core is movably arranged to block or open the second valve port.

Use the technical scheme of the utility model, a guide's formula solenoid valve is provided, include: the valve cover structure is provided with a pilot valve cavity and a communication channel; the pilot valve core is movably arranged in the pilot valve cavity and is in limit fit with the inner wall of the pilot valve cavity; the valve seat structure is connected with the valve cover structure, a surrounding area between the valve cover structure and the valve seat structure forms a main valve cavity, and the main valve cavity is communicated with the pilot valve cavity through a communicating channel. By adopting the scheme, the communication between the pilot valve cavity and the main valve cavity is realized through the communication channel, the balance of the pressure between the pilot valve cavity and the main valve cavity is ensured in the process that the pilot valve core moves in the pilot valve cavity, the situation that the pilot valve core is difficult to move due to the large pressure difference between the pilot valve cavity and the main valve cavity is prevented, meanwhile, the communication channel is directly arranged on the valve cover structure, the situation that in the prior art, the pilot valve cavity and the main valve cavity are communicated by adding an exhaust part in an auxiliary mode, the machining process and the machining cost of the pilot type electromagnetic valve are increased is avoided, and the machining cost of the pilot type electromagnetic valve is reduced.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic structural diagram of a pilot-operated solenoid valve provided in an embodiment of the present invention;

fig. 2 is a schematic structural view showing a valve cover structure in the pilot type solenoid valve of fig. 1;

FIG. 3 is a schematic structural view of the valve cover structure of FIG. 2 from another perspective;

FIG. 4 shows a top view of FIG. 1;

FIG. 5 showsbase:Sub>A cross-sectional view A-A of FIG. 4;

fig. 6 shows a cross-sectional view B-B of fig. 4.

Wherein the figures include the following reference numerals:

10. a valve cover structure; 11. a pilot valve cavity; 111. a first cavity section; 1111. a first limiting section; 1112. a second limiting section; 112. a second cavity section; 12. an upper valve cavity; 13. a communication channel;

20. a pilot valve spool; 21. a valve core main body; 22. an elastic member;

30. a drive structure; 31. a sleeve; 32. a movable iron core; 33. a stationary iron core; 34. a drive rod;

40. a valve seat structure; 41. a lower valve cavity; 42. a first flow-through channel; 43. a second flow-through channel;

50. a piston structure.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

As shown in fig. 1 to 6, an embodiment of the present invention provides a pilot-operated solenoid valve, including: a valve cover structure 10, the valve cover structure 10 having a pilot valve chamber 11 and a communication passage 13; the pilot valve core 20 is movably arranged in the pilot valve cavity 11 and is in limit fit with the inner wall of the pilot valve cavity 11; the valve seat structure 40, the valve seat structure 40 and the valve cover structure 10 are connected, and the surrounding area between the valve cover structure 10 and the valve seat structure 40 forms a main valve cavity which is communicated with the pilot valve cavity 11 through the communication passage 13.

In this embodiment, the communication between the pilot valve cavity 11 and the main valve cavity is realized through the communication channel 13, so that the pressure balance between the pilot valve cavity 11 and the main valve cavity is ensured in the process that the pilot valve core 20 moves in the pilot valve cavity 11, and the situation that the pilot valve core 20 is difficult to move due to a large pressure difference between the pilot valve cavity 11 and the main valve cavity is prevented, and meanwhile, the communication channel 13 is directly arranged on the valve cover structure 10, so that the situation that the pilot valve cavity 11 and the main valve cavity are communicated with each other by adding an exhaust part in the prior art to increase the processing procedure and the processing cost of the pilot type electromagnetic valve is avoided, and the processing cost of the pilot type electromagnetic valve is reduced.

As shown in fig. 5 and 6, the pilot valve chamber 11 includes a first chamber section 111 and a second chamber section 112 that are communicated with each other and coaxial, a radial dimension of the second chamber section 112 is smaller than a radial dimension of the first chamber section 111, inner walls of the pilot valve core 20 and the second chamber section 112 are in limit fit, an area between an inner side wall of the first chamber section 111 and an outer side wall of the pilot valve core 20 forms an annular chamber, and the communication channel 13 is disposed on the valve cover structure 10 and is respectively communicated with the annular chamber and the main valve chamber.

In this embodiment, the communication passage is mainly used for communicating the annular chamber and the main valve chamber, so as to ensure the pressure balance between the two chambers during the movement of the pilot valve core 20, prevent the situation that the pilot valve core 20 is difficult to move due to the large pressure difference between the pilot valve chamber 11 and the main valve chamber, and ensure the reliability of the movement of the pilot valve core 20.

Specifically, the first cavity section 111, the second cavity section 112 and the main valve cavity are all cylindrical cavities, the first cavity section 111, the second cavity section 112 and the main valve cavity are coaxial, the number of the communication passages 13 is multiple, and the plurality of the communication passages 13 are distributed at intervals along the circumferential direction of the second cavity section 112. By means of the arrangement, the communication area between the annular cavity and the main valve cavity is increased through the plurality of communication channels 13, and the pressure balance efficiency of the two cavities in the moving process of the pilot valve core 20 is improved.

In the present embodiment, the valve cover structure 10 includes an integrally molded annular plate, the annular plate is located in the pilot valve cavity 11, a region surrounded in the annular plate forms the second cavity section 112, and the communication channel 13 is disposed through the annular plate, wherein an area of the communication channel 13 in a radial cross section of the annular plate is smaller than or equal to an area of a solid structure of the annular plate in a radial direction. By limiting the two areas, the structural strength of the annular structure between the second cavity segment 112 and the second limiting segment 1112 after the communicating channel 13 is removed is ensured. Specifically, the radial area of the annular plate when not penetrated by the communicating passage 13 is an annular area, that is, the difference between the area of a circle in which the outer diameter of the annular plate is located and the area of a circle in which the inner diameter of the annular plate is located, which is referred to herein as the annular area of the original annular plate; after the communication channel 13 penetrates through the annular plate, the area of the annular plate in the radial direction is reduced, and the reduced area is the area of the communication channel on the radial section of the annular plate, it can be understood that the communication channel 13 penetrates through the solid structure of the original annular plate to form a gap, and the proportion of the radial area of the gap portion on the annular area of the original annular plate cannot exceed half of the annular area of the original annular plate, that is, on the radial section of the annular plate, the area of the communication channel 13 deducted from the original annular plate is smaller than or equal to the radial area of the solid structure of the deducted annular plate.

Further, the communication channel 13 is arranged on the inner wall of the second cavity section 112 and a part of the inner wall of the first cavity section 111, and the extending direction of the communication channel 13 is parallel to the axis of the second cavity section 112. Due to the arrangement, the processing of the communicating channel 13 is facilitated, namely, the processing of the communicating channel 13 can be realized by adopting a mode or a device for processing the second cavity section 112 or the first cavity section 111, and the processing efficiency of the pilot-operated electromagnetic valve is improved.

As shown in fig. 2 to 6, the first cavity segment 111 includes a first position-limiting segment 1111 and a second position-limiting segment 1112 that are communicated with each other, the second position-limiting segment 1112 is communicated with the second cavity segment 112, the radial dimension of the first position-limiting segment 1111 is greater than the radial dimension of the second position-limiting segment 1112, and a part of the communication channel 13 is disposed on the inner wall of the second position-limiting segment 1112.

In the present embodiment, an area between an inner side wall of the second position-limiting section 1112 and an outer side wall of the pilot valve core 20 forms an annular cavity, a part of the communication channel 13 is disposed on the second chamber section 112 and is communicated with the second chamber section 112, and another part of the communication channel 13 is disposed on the second position-limiting section 1112 and is communicated with the annular cavity, so as to ensure pressure balance between the annular cavity and the second chamber section 112.

Specifically, the cross section of the communication channel 13 in the radial direction of the second cavity segment 112 and the cross section of the communication channel 13 in the radial direction of the second limiting segment 1112 are both circular arcs, the circular arc radii of the two circular arcs are the same and coincide in the axial direction of the second cavity segment 112, the arc length of the circular arc cross section of the communication channel 13 in the radial direction of the second cavity segment 112 is greater than the arc length of the circular arc cross section of the communication channel 13 in the radial direction of the second limiting segment 1112, the length of the communication channel 13 extending in the axial direction of the pilot valve cavity 11 is L1, the axial length of the second cavity segment 112 is L2, the axial length of the second limiting segment 1112 is L3, and L2 < L1 < (L2 + L3). By this arrangement, the reliability of the communication between the annular chamber and the second chamber section 112 is ensured by the definition of L1, L2 and L3. Specifically, if L2 ≧ L1, the communication passage 13 may communicate only with the second cavity section 112 without communicating with the annular cavity, and if L1 ≧ (L2 + L3), the structural strength of the valve cover structure 10 in which the second stopper section 1112 is located may be reduced. And set up like this, be convenient for realize the one shot forming to intercommunication passageway 13, improve machining efficiency.

Alternatively, the cross section of the communication passage 13 may also be rectangular, triangular, or the like.

Further, the cross section of the communication channel 13 in the radial direction of the second cavity segment 112 and the cross section of the communication channel 13 in the radial direction of the second position-limiting segment 1112 are two coincided semicircles with the same arc radius, the arc radii of the two semicircles are both r1, the diameter of the second cavity segment 112 is D1, the diameter of the second position-limiting segment 1112 is D2, and D2/2 < (r 1+ D1/2).

In the present embodiment, the cross section of the communication channel 13 is semicircular, and the definition of D1, D2 and r1 ensures the reliability of the communication channel 13 communicating the annular cavity and the second cavity 112. Specifically, if D2/2 ≧ (r 1+ D1/2), the once-machined communication channel 13 only passes through the second cavity segment 112 but does not pass through the second stopper segment 1112, resulting in a situation where the communication channel 13 only communicates with the second cavity segment 112 but does not communicate with the annular cavity.

As shown in fig. 1, the pilot-operated solenoid valve further includes a driving structure 30, the driving structure 30 includes a sleeve 31, a movable iron core 32, a stationary iron core 33 and a driving rod 34, the stationary iron core 33 is located between the movable iron core 32 and the pilot valve core 20 and is fixedly disposed in the sleeve 31, the movable iron core 32 is movably disposed in the sleeve 31, one end of the driving rod 34 is connected to the movable iron core 32, the other end of the driving rod 34 is abutted to the pilot valve core 20, one end of the sleeve 31 is inserted into the first limiting section 1111 and is abutted to the bottom wall of the first limiting section 1111, and the outer wall of the sleeve 31 is in limit fit with the inner wall of the first limiting section 1111. With this arrangement, the stationary iron core 33 is fixedly disposed at a side close to the opening in the sleeve 31, and the movable iron core 32 is movably disposed to push the pilot valve core 20 abutting against one end of the driving rod 34. Through the limiting matching of the sleeve 31 and the first limiting section 1111, the displacement of the sleeve 31 and the valve cover structure 10 in the radial direction of the valve cover structure 10 is limited, and the coaxiality of the sleeve 31 and the valve cover structure 10 is ensured.

Specifically, the pilot valve element 20 includes a valve element main body 21 and an elastic member 22 disposed around the valve element main body 21, two ends of the elastic member 22 respectively abut against the bottom walls of the valve element main body 21 and the second limiting section 1112, and the outer peripheral surface of the elastic member 22 is in limiting fit with the inner wall of the second limiting section 1112. By means of the arrangement, the compression or the extension of the elastic piece 22 provides buffering and power for the movement of the valve core main body 21, and the reliability of the movement of the valve core main body 21 is ensured.

Further, the pilot-operated solenoid valve further comprises a piston structure 50, the piston structure 50 is disposed in the main valve cavity and divides the main valve cavity into an upper valve cavity 12 located in the valve cover structure 10 and a lower valve cavity 41 located in the valve seat structure 40, the valve seat structure 40 has a first flow passage 42 and a second flow passage 43, the first flow passage 42 has a first valve port communicated with the lower valve cavity 41, the piston structure 50 has a second valve port communicated with the upper valve cavity 12 and the lower valve cavity 41, the second flow passage 43 is communicated with the lower valve cavity 41, the piston structure 50 is disposed in the lower valve cavity 41 in an arched manner to block or open the first valve port, and the pilot valve core 20 is movably disposed to block or open the second valve port.

In the present embodiment, the pilot-operated solenoid valve is a normally open valve, fig. 1 shows a to-be-opened state of the pilot-operated solenoid valve, the second valve port on the piston structure 50 is normally open, fluid flows through the second flow channel 43 and enters the lower valve chamber 41 through a gap between the piston structure 50 and the valve seat structure 40 and a balance hole on the piston structure 50, because the piston structure 50 separates the upper valve chamber 12 from the lower valve chamber 41 and the fluid continuously enters the lower valve chamber 41, a pressure difference between the lower valve chamber 41 and the upper valve chamber 12 is large, the piston structure 50 arches upward under the action of the pressure difference and opens the first valve port on the first flow channel 42, the upper end surface of the piston structure 50 protrudes and stops against the bottom wall of the upper valve chamber 12, the piston member with the second valve port at the center of the piston structure 50 rises, and the second flow channel 43 is communicated with the first flow channel 42. The procedure of disconnecting the first and second flow channels 42 and 43 is as follows: the driving structure 30 is energized, the movable iron core 32 of the driving structure 30 moves towards the static iron core 33 and abuts against the static iron core 33 under the action of a magnetic field, the driving rod 34 abutting against the movable iron core 32 abuts against the valve core main body 21 and pushes the valve core main body 21 to move downwards, and the elastic element 22 surrounding the valve core main body 21 is compressed, wherein two ends of the elastic element 22 respectively abut against step surfaces formed among the valve core main body 21, the first cavity section and the second cavity section, in the moving process of the valve core main body 21, the sealing gasket in the valve core main body 21 abuts against the piston structure 50 and blocks a second valve port on the piston element, so that the pressure difference between the upper valve cavity 12 and the lower valve cavity 41 is balanced, the valve core main body 21 continues to move downwards, the piston element extends into the valve core main body 21 and pushes the sealing gasket in the valve core main body 21 upwards, and compresses a return elastic element, two ends of which respectively abut against the sealing gasket and the inner cavity top wall of the valve core main body 21, until the valve core main body 21 presses the piston structure 50 to a horizontal state and blocks a first valve port on the first flow channel 42, and communication between the first flow channel 42 and the second flow channel 43 is disconnected. When the valve needs to be opened again, only the magnetic field of the driving structure 30 needs to be closed, so that the adsorption effect of the movable iron core 32 and the stationary iron core 33 in the driving structure 30 disappears, specifically, the movable iron core 32 of the driving structure 30 does not adsorb toward the stationary iron core 33 any more after the magnetic field fails, the valve core main body 21 moves upward under the tension of the compressed elastic member 22, the restoration of the movable iron core 32 of the valve core main body 21 and the driving structure 30 is realized, meanwhile, the restoration elastic member stretches, so that the sealing gasket is restored, in the process, the sealing gasket is abutted and separated from the piston member of the piston structure 50, the second valve port is reopened, and under the action of the fluid flowing through the second flow passage 43 and the lower valve chamber 41, the pressure difference is newly generated between the upper valve chamber 12 and the lower valve chamber 41, the upward arching of the valve port of the piston structure 50 is realized again, and the first flow passage 42 and the second flow passage 43 are opened.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (11)

1. A pilot operated solenoid valve, comprising:

a valve cover structure (10), the valve cover structure (10) having a pilot valve cavity (11) and a communication passage (13);

the pilot valve core (20) is movably arranged in the pilot valve cavity (11) and is in limit fit with the inner wall of the pilot valve cavity (11);

a valve seat structure (40), the valve seat structure (40) and the valve cover structure (10) are connected, and the surrounding area between the valve cover structure (10) and the valve seat structure (40) forms a main valve cavity which is communicated with the pilot valve cavity (11) through the communication channel (13).

2. The pilot-operated solenoid valve according to claim 1, characterized in that the pilot valve chamber (11) comprises a first chamber section (111) and a second chamber section (112) which are communicated with each other and coaxial, the radial dimension of the second chamber section (112) is smaller than that of the first chamber section (111), the pilot valve spool (20) is in limit fit with the inner wall of the second chamber section (112), the area between the inner side wall of the first chamber section (111) and the outer side wall of the pilot valve spool (20) forms an annular chamber, and the communication channel (13) is arranged on the bonnet structure (10) and is communicated with the annular chamber and the main valve chamber respectively.

3. The pilot operated solenoid valve according to claim 2, wherein the first chamber section (111), the second chamber section (112) and the main valve chamber are cylindrical chambers, the first chamber section (111) and the main valve chamber are coaxial, the communication passage (13) is plural, and the plurality of communication passages (13) are spaced apart along a circumferential direction of the second chamber section (112).

4. The pilot-operated solenoid valve according to claim 2, wherein the valve cover structure (10) comprises an integrally formed annular plate located within the pilot valve chamber (11), an area surrounding within the annular plate forming the second cavity section (112), the communication channel (13) being provided through the annular plate, wherein an area of the communication channel (13) in a radial cross section of the annular plate is less than or equal to an area of a solid structure of the annular plate in a radial direction.

5. Piloted solenoid valve according to claim 2, characterized in that said communication channel (13) is pierced on the internal wall of said second chamber section (112) and on part of the internal wall of said first chamber section (111), the extension direction of said communication channel (13) being parallel to the axis of said second chamber section (112).

6. Pilot-operated solenoid valve according to claim 2, characterized in that the first chamber section (111) comprises a first limit section (1111) and a second limit section (1112) communicating with each other, the second limit section (1112) and the second chamber section (112) communicating, the first limit section (1111) having a radial dimension greater than the second limit section (1112), a portion of the communication channel (13) passing on the inner wall of the second limit section (1112).

7. The pilot-operated solenoid valve according to claim 6, wherein a cross section of the communication passage (13) in a radial direction of the second cavity segment (112) and a cross section of the communication passage (13) in a radial direction of the second stopper segment (1112) are circular arcs, circular arc radii of the two circular arcs are the same and coincide in an axial direction of the second cavity segment (112), an arc length of the circular arc cross section of the communication passage (13) in the radial direction of the second cavity segment (112) is greater than an arc length of the circular arc cross section of the communication passage (13) in the radial direction of the second stopper segment (1112), a length of the communication passage (13) extending in the axial direction of the pilot valve cavity (11) is L1, an axial length of the second cavity segment (112) is L2, an axial length of the second stopper segment (1112) is L3, and L2 < L1 < (L2 + L3).

8. The pilot-operated solenoid valve according to claim 6, wherein the cross section of the communication channel (13) in the radial direction of the second chamber segment (112) and the cross section of the communication channel (13) in the radial direction of the second retainer segment (1112) are two coincident semi-circles having equal arc radii, both the arc radii of the two semi-circles are r1, the diameter of the second chamber segment (112) is D1, the diameter of the second retainer segment (1112) is D2, and D2/2 < (r 1+ D1/2).

9. The pilot-operated solenoid valve according to claim 6, characterized in that the pilot-operated solenoid valve further comprises a driving structure (30), the driving structure (30) comprises a sleeve (31), a movable iron core (32), a static iron core (33) and a driving rod (34), the static iron core (33) is located between the movable iron core (32) and the pilot-operated valve core (20) and is fixedly arranged in the sleeve (31), the movable iron core (32) is movably arranged in the sleeve (31), one end of the driving rod (34) is connected with the movable iron core (32), the other end of the driving rod (34) is abutted with the pilot-operated valve core (20), one end of the sleeve (31) is inserted in the first limit section (1111) and is abutted with the bottom wall of the first limit section (1111), and the outer wall of the sleeve (31) is in limit fit with the inner wall of the first limit section (1111).

10. The pilot-operated electromagnetic valve according to claim 6, wherein the pilot-operated valve spool (20) includes a spool main body (21) and an elastic member (22) disposed around the spool main body (21), two ends of the elastic member (22) are respectively abutted to the spool main body (21) and a bottom wall of the second limiting section (1112), and an outer peripheral surface of the elastic member (22) is in limiting fit with an inner wall of the second limiting section (1112).

11. The pilot-operated solenoid valve according to claim 1, further comprising a piston structure (50), wherein the piston structure (50) is disposed in the main valve chamber and divides the main valve chamber into an upper valve chamber (12) located in the valve cover structure (10) and a lower valve chamber (41) located in the valve seat structure (40), the valve seat structure (40) has a first flow passage (42) and a second flow passage (43), the first flow passage (42) has a first valve port communicating with the lower valve chamber (41), the piston structure (50) has a second valve port communicating with the upper valve chamber (12) and the lower valve chamber (41), the second flow passage (43) communicates with the lower valve chamber (41), the piston structure (50) is archwardly disposed in the lower valve chamber (41) to close or open the first valve port, and the pilot-operated valve spool (20) is movably disposed to close or open the second valve port.

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