A pilot-controlled solenoid valve

Abstract

The present invention relates to the field of hydraulic valve technology, and in particular to a pilot-controlled solenoid valve. The pilot-controlled solenoid valve includes a magnetic sleeve, a coil, a valve sleeve, an armature assembly, a main valve core, a pilot valve core, and an elastic centering assembly. The movable iron member of the armature assembly is inserted into the magnetic sleeve and can move axially relative to the magnetic sleeve in response to the electromagnetic force generated by the coil. A first pressure oil chamber and a second pressure oil chamber are formed between the valve sleeve and the main valve core. The pressure difference between the first and second pressure oil chambers can drive the main valve core to move. When the movable iron member drives the pilot valve core to move relative to the main valve core, the pressure difference between the first and second pressure oil chambers can be adjusted. The elastic centering assembly is disposed on the main valve core and always has a tendency to hinder the movement of the main valve core relative to the valve sleeve. When there is no pressure difference between the first and second pressure oil chambers, the pilot-controlled solenoid valve can ensure that the main valve core is in a neutral position, thereby ensuring the reliability of the pilot-controlled solenoid valve.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic valves, and in particular to a pilot-controlled solenoid valve. Background Art

[0002] The hydraulic threaded cartridge solenoid valve is the main component of the hydraulic system reversing control. It has the advantages of easy installation and small size. In addition, the pilot control acts as a power amplifier to control the power stage main valve core through the pilot valve core with a small driving force, which can achieve rapid switching of large flow rates.

[0003] Existing pilot-controlled solenoid valves typically have a first pressure oil chamber and a second pressure oil chamber between the valve sleeve and the main valve core. The pressure differential between the first and second pressure oil chambers is adjusted by the movement of the pilot valve core, which in turn drives the movement of the main valve core to achieve flow control of the pilot-controlled solenoid valve. However, in the initial state of the pilot-controlled solenoid valve, that is, when there is no pressure differential between the first and second pressure oil chambers, the relative position of the main valve core is prone to shifting, making it impossible to maintain the main valve core in the neutral position, significantly reducing the reliability of the pilot-controlled solenoid valve.

[0004] Therefore, there is an urgent need for a pilot-controlled solenoid valve to solve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide a pilot-controlled solenoid valve, which can ensure that the main valve core is in the middle position when there is no pressure difference between the first pressure oil chamber and the second pressure oil chamber of the pilot-controlled solenoid valve, thereby ensuring the reliability of the pilot-controlled solenoid valve.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A pilot-controlled solenoid valve, comprising:

[0008] Magnetic sleeve;

[0009] A coil, wherein the coil is sleeved on the outer periphery of the magnetic sleeve;

[0010] a valve sleeve connected to an end of the magnetic sleeve, and having a plurality of oil ports spaced apart thereon;

[0011] An armature assembly, the armature assembly comprising a movable iron member, the movable iron member being inserted into the magnetic sleeve and capable of moving relative to the magnetic sleeve along the axial direction of the magnetic sleeve in response to the electromagnetic force generated by the coil;

[0012] a main valve core, which is inserted into the valve sleeve and can move relative to the valve sleeve along the axial direction of the valve sleeve to connect or block the multiple oil ports; the valve sleeve and the main valve core cooperate to form a first pressure oil chamber and a second pressure oil chamber; the pressure difference between the first pressure oil chamber and the second pressure oil chamber can drive the main valve core to move;

[0013] a pilot valve core, which is inserted into the main valve core and fixedly connected to the movable iron member, and the movable iron member drives the pilot valve core to move relative to the main valve core to adjust the pressure difference between the first pressure oil chamber and the second pressure oil chamber; and

[0014] The elastic centering component is provided on the main valve core, and the elastic centering component is configured to always have a tendency to hinder the main valve core from moving relative to the valve sleeve.

[0015] As an optional solution, a first abutting portion and a second abutting portion are provided on the outer peripheral wall of the main valve core, and the first abutting portion and the second abutting portion are arranged at intervals along the axial direction of the main valve core;

[0016] The armature assembly further includes a stop iron fixedly disposed in the magnetic conductive sleeve;

[0017] The elastic centering component includes a first limiting ring, a second limiting ring and a centering spring. The first limiting ring and the second limiting ring are both sleeved on the outer circumference of the main valve core. The first limiting ring and the second limiting ring are arranged at intervals along the axial direction of the main valve core. The side of the first limiting ring away from the second limiting ring can abut against the stop iron, and the side of the first limiting ring away from the second limiting ring abuts against the first abutting portion. The side of the second limiting ring away from the first limiting ring can abut against the valve sleeve, and the side of the second limiting ring away from the first limiting ring abuts against the second abutting portion. The centering spring is sleeved on the outer circumference of the main valve core, the first end of the centering spring abuts against the first limiting ring, and the second end of the centering spring abuts against the second limiting ring.

[0018] As an optional solution, the first abutting portion is an abutting protrusion fixedly sleeved on the outer peripheral wall of the main valve core, or the first abutting portion is a positioning shoulder provided on the outer peripheral wall of the main valve core;

[0019] The second abutting portion is an abutting protrusion fixedly sleeved on the outer peripheral wall of the main valve core, or the second abutting portion is a positioning shoulder provided on the outer peripheral wall of the main valve core.

[0020] As an optional solution, the movable iron member includes:

[0021] A moving iron, wherein the moving iron and the stop iron are spaced apart along the axial direction of the main valve core, and the stop iron can abut against the moving iron to limit the limit position of the moving iron moving relative to the magnetic sleeve toward the valve sleeve; and

[0022] A connecting rod, wherein the first end of the connecting rod is connected to the inner cavity of the moving iron, the second end of the connecting rod is passed through the inner cavity of the stop iron, and the second end of the connecting rod is fixedly connected to the pilot valve core.

[0023] As an optional solution, the pilot-controlled solenoid valve further includes:

[0024] An elastic return component is configured to always have a tendency to hinder the pilot valve core from moving.

[0025] As an optional solution, a third abutment portion is provided on the outer peripheral wall of the connecting rod, and a fourth abutment portion is provided on the outer peripheral wall of the pilot valve core or on the outer peripheral wall of the connecting rod, and the third abutment portion and the fourth abutment portion are arranged at intervals along the axial direction of the pilot valve core;

[0026] The elastic reset assembly includes a third limiting ring, a fourth limiting ring and a reset spring, the third limiting ring and the fourth limiting ring are arranged at intervals along the axial direction of the pilot valve core, the third limiting ring is sleeved on the outer circumference of the connecting rod, the side of the third limiting ring away from the fourth limiting ring can abut against the stop iron, and the side of the third limiting ring away from the fourth limiting ring abuts against the third abutting portion, the fourth limiting ring is sleeved on the outer circumference of the pilot valve core or the connecting rod, the side of the fourth limiting ring away from the third limiting ring can abut against the stop iron, and the side of the fourth limiting ring away from the third limiting ring abuts against the fourth abutting portion, the first end of the reset spring abuts against the third limiting ring, and the second end of the reset spring abuts against the fourth limiting ring.

[0027] As an optional solution, the valve sleeve is provided with a first oil port, a second oil port, a third oil port, a fourth oil port and a fifth oil port in sequence and spaced along its axial direction;

[0028] The main valve core is provided with a first oil delivery hole communicating with the first pressure oil chamber, and the main valve core is also provided with a second oil delivery hole communicating with the second pressure oil chamber;

[0029] A pilot oil circuit is provided on the pilot valve core, which connects or blocks the first pressure oil chamber when the pilot valve core moves relative to the main valve core, and connects or blocks the second pressure oil chamber when the pilot valve core moves relative to the main valve core.

[0030] As an optional solution, the first oil port and the fifth oil port are oil inlet ports, the second oil port and the fourth oil port are working oil ports, and the third oil port is an oil unloading port;

[0031] An annular cavity is provided between the main valve core and the pilot valve core, the annular cavity being connectable to the first pressure oil cavity or the second pressure oil cavity, and shoulders at both ends of the annular cavity being used to seal the first oil delivery hole and the second oil delivery hole respectively;

[0032] The pilot valve core is provided with a first channel and a second channel at both ends along its axial direction, and the first channel, the second channel and the annular cavity are connected to form the pilot oil circuit;

[0033] A valve hole communicating with the first pressure oil chamber and the second pressure oil chamber is formed in the side wall of the main valve core along its axial direction, and the valve hole is communicated with the oil inlet.

[0034] As an optional solution, the first channel, the annular cavity and the oil unloading port are connected to form a first pressure relief flow channel;

[0035] An oil inlet hole communicating with the inner cavity of the magnetic sleeve is formed at the end of the pilot valve core along its radial direction. The oil inlet hole is communicated with the second channel. The oil inlet hole, the second channel, the annular cavity and the oil unloading port are connected to form a second pressure relief flow channel.

[0036] As an optional solution, the valve sleeve and the main valve core cooperate to form a third annular cavity and a fourth annular cavity, a connecting boss is provided between the third annular cavity and the fourth annular cavity, and a connecting hole is provided on the connecting boss for connecting the third oil port and the pilot oil circuit;

[0037] When the main valve core moves, the third annular cavity can connect the second oil port to or block the first oil port, the third annular cavity can connect the second oil port to or block the third oil port, the fourth annular cavity can connect the fourth oil port to or block the third oil port, and the fourth annular cavity can connect the fourth oil port to or block the fifth oil port.

[0038] Beneficial effects of the present invention:

[0039] The present invention provides a pilot-controlled solenoid valve, which is achieved by arranging a coil on the outer periphery of a magnetic sleeve, connecting the valve sleeve to the end of the magnetic sleeve, and inserting a moving iron piece into the magnetic sleeve and being able to move relative to the magnetic sleeve along the axial direction of the magnetic sleeve with the electromagnetic force generated by the coil. The main valve core is inserted into the valve sleeve, and the pilot valve core is inserted into the main valve core. The valve sleeve and the main valve core cooperate to form a first pressure oil chamber and a second pressure oil chamber. When the moving iron piece moves and drives the pilot valve core to move relative to the main valve core, the pressure difference between the first pressure oil chamber and the second pressure oil chamber can be adjusted. The pressure difference between the first pressure oil chamber and the second pressure oil chamber can drive the main valve core to move, so as to connect or block multiple oil ports on the valve sleeve, thereby realizing flow control of the pilot-controlled solenoid valve. In addition, the pilot-controlled solenoid valve is equipped with an elastic centering component on the main valve core, and the elastic centering component always has a tendency to hinder the movement of the main valve core relative to the valve sleeve, so that the pilot-controlled solenoid valve can ensure that the main valve core is in the middle position in the initial state, that is, when there is no pressure difference between the first pressure oil chamber and the second pressure oil chamber, thereby ensuring the reliability of the pilot-controlled solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a cross-sectional view of the structure of a pilot-controlled solenoid valve provided in Example 1 of the present invention;

[0041] Figure 2 This is a first partial structural sectional view of a pilot-controlled solenoid valve provided in the first embodiment of the present invention;

[0042] Figure 3 This is a second partial structural sectional view of the pilot-controlled solenoid valve provided in the first embodiment of the present invention;

[0043] Figure 4 This is a cross-sectional view of the structure of a pilot-controlled solenoid valve provided in the second embodiment of the present invention;

[0044] Figure 5 It is a partial structural cross-sectional view of a pilot-controlled solenoid valve provided in the second embodiment of the present invention.

[0045] In the picture:

[0046] 1. Magnetic guide sleeve; 11. Magnetic isolation tube; 12. Tail screw; 13. Front screw; 14. Lock nut;

[0047] 2. Coil; 21. First coil; 22. Second coil; 23. Gasket;

[0048] 3. Valve sleeve; 31. First oil port; 32. Second oil port; 33. Third oil port; 34. Fourth oil port; 35. Fifth oil port; 36. Step surface; 37. Shaft seal; 38. Retaining ring; 39. Positioning boss; 391. Sealing retaining ring; 392. Sealing ring;

[0049] 4. Armature assembly; 41. Moving iron member; 411. Moving iron member; 412. Connecting rod; 4121. Third abutting portion; 413. Cylindrical pin; 42. Stop iron member;

[0050] 5. Main valve core; 51. First abutment portion; 52. Second abutment portion; 53. First oil delivery hole; 54. Second oil delivery hole; 55. Valve hole; 56. Connecting boss; 561. Communication hole; 57. Oil unloading hole; 58. First blind hole; 581. First connecting hole; 59. Second blind hole; 591. Second connecting hole;

[0051] 6. Pilot valve core; 61. Fourth abutment portion; 63. First passage; 64. Second passage; 65. Oil inlet hole; 66. First shoulder; 67. Second shoulder; 6a. Oil passage hole; 611. Oil passage;

[0052] 7. Elastic centering assembly; 71. First limiting ring; 72. Second limiting ring; 73. Centering spring;

[0053] 8. Elastic reset assembly; 81. Third limiting ring; 82. Fourth limiting ring; 83. Reset spring;

[0054] p1, first pressure oil chamber; p2, second pressure oil chamber; b, annular chamber; b1, first annular chamber; b2, second annular chamber; b4, third annular chamber; b5, fourth annular chamber. DETAILED DESCRIPTION

[0055] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the present invention are further described below with reference to the accompanying drawings and through specific implementation methods.

[0056] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0057] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0058] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0059] Example 1

[0060] like Figure 1 and Figure 2 As shown, this embodiment provides a pilot-controlled solenoid valve, which includes a magnetic sleeve 1, a coil 2, a valve sleeve 3, an armature assembly 4, a main valve core 5 and a pilot valve core 6, wherein the coil 2 is sleeved on the outer periphery of the magnetic sleeve 1, the valve sleeve 3 is connected to the right end of the magnetic sleeve 1, and a plurality of oil ports are spaced apart on the valve sleeve 3. The armature assembly 4 includes a movable iron member 41, which is inserted into the magnetic sleeve 1 and can move relative to the magnetic sleeve 1 along the axial direction (left and right direction in the figure) of the magnetic sleeve 1 with the electromagnetic force generated by the coil 2. The main valve core 5 is inserted into the valve sleeve 3. The valve sleeve 3 is provided with a first pressure oil chamber p1 and a second pressure oil chamber p2, and is capable of moving relative to the valve sleeve 3 along the axial direction of the valve sleeve 3 (left-right direction in the figure) to open or close multiple oil ports. The valve sleeve 3 and the main valve core 5 cooperate to form a first pressure oil chamber p1 and a second pressure oil chamber p2. The pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2 can drive the main valve core 5 to move. The pilot valve core 6 is disposed within the main valve core 5 and is fixedly connected to a movable iron member 41. The movable iron member 41 drives the pilot valve core 6 to move relative to the main valve core 5 to adjust the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2. The pilot-controlled solenoid valve provided in this embodiment can adjust the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2 by moving the movable iron member 41 relative to the main valve core 5. The pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2 can drive the main valve core 5 to move, thereby opening or closing multiple oil ports on the valve sleeve 3, thereby achieving flow control of the pilot-controlled solenoid valve.

[0061] In this embodiment, if Figure 1 and Figure 3 As shown, the movable iron member 41 includes a movable iron 411 and a connecting rod 412. The first end of the connecting rod 412 (i.e., the left end of the connecting rod 412) is connected to the inner cavity of the movable iron 411, and the second end of the connecting rod 412 (i.e., the right end of the connecting rod 412) is fixedly connected to the pilot valve core 6. Optionally, the movable iron member 41 further includes a cylindrical pin 413, and the first end of the connecting rod 412 is connected to the inner cavity of the movable iron 411 via the cylindrical pin 413.

[0062] In this embodiment, if Figure 1 and Figure 3 As shown, the armature assembly 4 also includes a stopper 42, which is fixedly disposed within the magnetic sleeve 1. The stopper 42 and the movable iron 411 are spaced apart along the axial direction of the main valve core 5 (left-right direction in the figure). The second end of the connecting rod 412 is disposed within the inner cavity of the stopper 42 and is fixedly connected to the pilot valve core 6. The stopper 42 can abut against the movable iron 411 to limit the maximum position of the movable iron 411 relative to the magnetic sleeve 1 toward the valve sleeve 3 (i.e., to the right). Optionally, in this embodiment, a limiting groove is provided at the left end of the stopper 42, which can abut against the right end of the movable iron 411, thereby limiting the maximum position of the movable iron 411 relative to the magnetic sleeve 1 to the right.

[0063] like Figure 1 and Figure 3 As shown, the magnetic sleeve 1 includes a magnetic isolation tube 11, a tail collar 12, a front collar 13 and a locking nut 14, wherein the outer periphery of the magnetic isolation tube 11 is provided with a coil 2, the left end of the magnetic isolation tube 11 is provided with a tail collar 12, the right end of the magnetic isolation tube 11 is provided with a front collar 13, and the left end of the tail collar 12 is threadedly connected to the locking nut 14, which is used to tighten the coil 2 against the left end of the front collar 13, thereby preventing the coil 2 from moving in the axial direction and achieving the fixation of the coil 2 on the outer periphery of the magnetic sleeve 1. Optionally, in this embodiment, the right end of the tail collar 12 can abut against the left end of the moving iron 411, thereby limiting the limit position of the moving iron 411 moving away from the valve sleeve 3 (i.e., to the left). Optionally, in this embodiment, the right end of the tail collar 12 is provided with an abutment groove, which can abut against the left end of the moving iron 411, thereby limiting the limit position of the moving iron 411 moving to the left relative to the magnetic sleeve 1.

[0064] Alternatively, as Figure 1 and Figure 3As shown, the coil 2 includes a first coil 21, a second coil 22, and a gasket 23. The first coil 21 and the second coil 22 are spaced apart along the axial direction (left-right direction in the figure) of the magnetic isolation tube 11, and the gasket 23 is sandwiched between the first coil 21 and the second coil 22, thereby isolating the first coil 21 and the second coil 22. It should be noted that in this embodiment, when both the first coil 21 and the second coil 22 are de-energized, no electromagnetic force is generated, and the pilot valve core 6 is in the neutral position. When the first coil 21 on the right is energized, the movable iron 411 drives the pilot valve core 6 to the right under the action of the magnetic field force. When the first coil 21 on the right is de-energized, the pilot valve core 6 can move to the left and return to the neutral position. When the second coil 22 on the left is energized, the movable iron 411 drives the pilot valve core 6 to the left under the action of the magnetic field force. When the second coil 22 on the left is de-energized, the pilot valve core 6 can move to the right and return to the neutral position.

[0065] Existing pilot-controlled solenoid valves adjust the pressure differential between the first and second pressure oil chambers p1 and p2 by moving the pilot valve core 6. This pressure differential between the first and second pressure oil chambers p1 and p2 drives the movement of the main valve core 5, achieving flow control of the pilot-controlled solenoid valve. However, in the pilot-controlled solenoid valve's initial state, i.e., when there is no pressure differential between the first and second pressure oil chambers p1 and p2, the relative position of the main valve core 5 is prone to shifting, making it impossible to maintain the main valve core 5 in its neutral position. This significantly reduces the reliability of the pilot-controlled solenoid valve.

[0066] In order to solve the above problems, Figure 1 and Figure 2 As shown, the pilot-controlled solenoid valve provided in this embodiment further includes an elastic centering component 7, which is disposed on the main valve core 5 and is configured to consistently obstruct movement of the main valve core 5 relative to the valve sleeve 3. By disposing the elastic centering component 7 on the main valve core 5 and ensuring that the elastic centering component 7 consistently obstructs movement of the main valve core 5 relative to the valve sleeve 3, the pilot-controlled solenoid valve can maintain the main valve core 5 in a neutral position in its initial state, i.e., when there is no pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2, thereby ensuring the reliability of the pilot-controlled solenoid valve.

[0067] Optionally, in this embodiment, if Figure 1 and Figure 2As shown, a first abutment portion 51 and a second abutment portion 52 are provided on the outer peripheral wall of the main valve core 5, and the first abutment portion 51 and the second abutment portion 52 are arranged at intervals along the axial direction of the main valve core 5. The elastic centering component 7 includes a first limiting ring 71, a second limiting ring 72 and a centering spring 73. The first limiting ring 71 and the second limiting ring 72 are both sleeved on the outer periphery of the main valve core 5, and the first limiting ring 71 and the second limiting ring 72 are arranged at intervals along the axial direction of the main valve core 5. The side of the first limiting ring 71 away from the second limiting ring 72 (that is, the left side of the first limiting ring 71) can abut against the stop iron 42 The first limiting ring 71 abuts against the first abutting portion 51 on one side away from the second limiting ring 72, and the second limiting ring 72 abuts against the valve sleeve 3 on the other side away from the first limiting ring 71 (i.e., the right side of the second limiting ring 72). Furthermore, the second limiting ring 72 abuts against the second abutting portion 52 on the other side away from the first limiting ring 71. A centering spring 73 is sleeved on the outer periphery of the main valve core 5. The first end of the centering spring 73 (i.e., the left end of the centering spring 73) abuts against the first limiting ring 71, and the second end of the centering spring 73 (i.e., the right end of the centering spring 73) abuts against the second limiting ring 72. The abutment and positioning of the centering spring 73 are achieved by the first limiting ring 71 and the second limiting ring 72, making the structure simple and reliable. Furthermore, the axial limiting installation of the elastic centering assembly 7 is achieved by the first abutting portion 51 and the second abutting portion 52 on the outer peripheral wall of the main valve core 5, making the structure even simpler and more reliable. In addition, when there is no pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2, the elastic force of the centering spring 73 also effectively prevents the main valve core 5 from deviating to the left or right, ensuring that the main valve core 5 is in the middle position.

[0068] Optionally, in this embodiment, if Figure 2 As shown, the first abutment portion 51 is a protruding abutment fixedly mounted on the outer peripheral wall of the main valve core 5. In other embodiments, the first abutment portion 51 may be a positioning shoulder provided on the outer peripheral wall of the main valve core 5. Alternatively, in this embodiment, the second abutment portion 52 is a positioning shoulder provided on the outer peripheral wall of the main valve core 5. In other embodiments, the second abutment portion 52 may also be a protruding abutment fixedly mounted on the outer peripheral wall of the main valve core 5.

[0069] In this embodiment, if Figure 1 and Figure 2 As shown, the pilot-controlled solenoid valve further includes an elastic return assembly 8, which is configured to always have a tendency to hinder the movement of the pilot valve core 6. By providing the elastic return assembly 8, when both the second coil 22 and the first coil 21 are de-energized, the elastic force of the elastic return assembly 8 facilitates the return of the pilot valve core 6 to a neutral position.

[0070] Optionally, in this embodiment, if Figure 1 and Figure 2As shown, a third abutment 4121 is provided on the outer peripheral wall of the connecting rod 412, and a fourth abutment 61 is provided on the outer peripheral wall of the pilot valve core 6. The third abutment 4121 and the fourth abutment 61 are arranged at intervals along the axial direction of the pilot valve core 6 (left and right directions in the figure), and the elastic reset assembly 8 includes a third limiting ring 81, a fourth limiting ring 82 and a reset spring 83. The third limiting ring 81 and the fourth limiting ring 82 are arranged at intervals along the axial direction of the pilot valve core 6, and the third limiting ring 81 is sleeved on the outer periphery of the connecting rod 412. The side of the third limiting ring 81 away from the fourth limiting ring 82 (that is, the left side of the third limiting ring 81) can abut against the stop iron 42, and the third limiting ring The side of the ring 81 away from the fourth limiting ring 82 abuts against the third abutment portion 4121, and the fourth limiting ring 82 is sleeved on the outer periphery of the pilot valve core 6. The side of the fourth limiting ring 82 away from the third limiting ring 81 (that is, the right side of the fourth limiting ring 82) can abut against the stop iron 42, and the side of the fourth limiting ring 82 away from the third limiting ring 81 abuts against the fourth abutment portion 61, and the return spring 83 is sleeved on the outer periphery of the connection between the connecting rod 412 and the pilot valve core 6, and the first end of the return spring 83 (that is, the left end of the return spring 83) abuts against the third limiting ring 81, and the second end of the return spring 83 (that is, the right end of the return spring 83) abuts against the fourth limiting ring 82. Specifically, when the first coil 21 on the right side is energized, the movable iron 411 drives the pilot valve core 6 to move rightward under the action of the magnetic field force. At this time, the third abutting portion 4121 pushes the return spring 83 to the right, and the fourth limiting ring 82 is abutted by the iron stop 42, causing the return spring 83 to be compressed. When the first coil 21 on the right side is de-energized, the pilot valve core 6 moves leftward under the elastic force of the return spring 83 and returns to the neutral position. When the second coil 22 on the left side is energized, the movable iron 411 drives the pilot valve core 6 to move leftward under the action of the magnetic field force. At this time, the fourth abutting portion 61 pushes the return spring 83 to the left, and the third limiting ring 81 is abutted by the iron stop 42, causing the return spring 83 to be compressed. When the second coil 22 on the left side is de-energized, the pilot valve core 6 moves rightward under the elastic force of the return spring 83 and returns to the neutral position. By providing the third limiting ring 81 and the fourth limiting ring 82 to achieve abutment and positioning of the return spring 83, the structure is simple and reliable. In addition, the third abutting portion 4121 and the fourth abutting portion 61 are provided to realize the position-limiting installation of the elastic reset assembly 8 in the axial direction, making the structure simpler and more reliable.

[0071] Alternatively, in this embodiment, the third abutting portion 4121 is an abutting protrusion provided on the outer peripheral wall of the connecting rod 412. Alternatively, in this embodiment, the fourth abutting portion 61 is an abutting protrusion provided on the outer peripheral wall of the pilot valve core 6.

[0072] In this embodiment, if Figure 1 and Figure 2As shown, the valve sleeve 3 is provided with a first oil port 31, a second oil port 32, a third oil port 33, a fourth oil port 34 and a fifth oil port 35 in sequence from right to left along its axial direction, a first oil delivery hole 53 communicating with the first pressure oil chamber p1 is provided on the main valve core 5, and a second oil delivery hole 54 communicating with the second pressure oil chamber p2 is also provided on the main valve core 5, and a pilot oil circuit is provided on the pilot valve core 6. The pilot oil circuit connects or blocks the first pressure oil chamber p1 when the pilot valve core 6 moves relative to the main valve core 5, and connects or blocks the second pressure oil chamber p2 when the pilot valve core 6 moves relative to the main valve core 5, thereby adjusting the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2.

[0073] Optionally, in this embodiment, if Figure 2 As shown, in order to facilitate the design of the specific structure of the first pressure oil chamber p1 and the second pressure oil chamber p2, step surfaces 36 are provided on the inner walls of both ends of the valve sleeve 3, and a shaft seal 37 is fitted on each step surface 36. The shaft seal 37 is installed and limited by a retaining ring 38 and the step surface 36. The end surface of one shaft seal 37, the inner wall of the valve sleeve 3 and the outer wall of the main valve core 5 cooperate to form the first pressure oil chamber p1, and the end surface of the other shaft seal 37, the inner wall of the valve sleeve 3 and the outer wall of the main valve core 5 cooperate to form the second pressure oil chamber p2.

[0074] Optionally, in this embodiment, if Figure 2 As shown, the valve sleeve 3 and the main valve core 5 cooperate to form a third annular cavity b4 and a fourth annular cavity b5. A connecting boss 56 is provided between the third annular cavity b4 and the fourth annular cavity b5. A connecting hole 561 for connecting the third oil port 33 and the pilot oil circuit is provided on the connecting boss 56. When the main valve core 5 moves, the third annular cavity b4 can connect the second oil port 32 to or block the first oil port 31, the third annular cavity b4 can connect the second oil port 32 to or block the third oil port 33, the fourth annular cavity b5 can connect the fourth oil port 34 to or block the third oil port 33, and the fourth annular cavity b5 can connect the fourth oil port 34 to or block the fifth oil port 35.

[0075] In order to facilitate the installation of the pilot-controlled solenoid valve and provide sealing when in use, in this embodiment, Figure 2 As shown, a retaining boss 39 is provided between the first oil port 31, the second oil port 32, the third oil port 33, the fourth oil port 34 and the fifth oil port 35, each retaining boss 39 is provided with a sealing groove, two sealing rings 391 are provided on the sealing groove, and a sealing ring 392 is clamped between the sealing rings 391.

[0076] Optionally, in this embodiment, if Figure 1 and Figure 2As shown, the first oil port 31 and the fifth oil port 35 are oil inlets, that is, the first oil port 31 and the fifth oil port 35 are connected to the oil source for providing high-pressure oil, the second oil port 32 and the fourth oil port 34 are working oil ports for connecting to the load, such as the rod chamber and the rodless chamber of the cylinder, the third oil port 33 is an oil unloading port, and the third oil port 33 is used to connect to the oil tank; an annular cavity b is provided between the main valve core 5 and the pilot valve core 6, and the annular cavity b can be connected to the first pressure oil chamber p1 or the second pressure oil chamber p2, and the shoulders at both ends of the annular cavity b are used to seal the first oil delivery hole 53 and the second oil delivery hole 54 respectively, and the pilot valve core 6 is respectively provided with a first channel 63 and a second channel 64 at both ends along its axial direction, and the first channel 63, the second channel 64 and the annular cavity b are connected to form a pilot oil circuit, and the side wall of the main valve core 5 is provided with a valve hole 55 along its axial direction that is connected to the first pressure oil chamber p1 and the second pressure oil chamber p2, and the valve hole 55 is connected to the oil inlet.

[0077] To prevent the armature assembly 4, main valve core 5, and pilot valve core 6 from getting stuck during movement, the first channel 63, the annular cavity b, and the oil unloading port are connected to form a first pressure relief channel. The pilot valve core 6 has an oil inlet hole 65 radially defined at its end, communicating with the inner cavity of the magnetic sleeve 1. The oil inlet hole 65 is connected to the second channel 64, and the oil inlet hole 65, the second channel 64, the annular cavity b, and the oil unloading port are connected to form a second pressure relief channel. The oil in the magnetic sleeve 1 can flow through the gap to the second pressure relief channel and return to the oil tank for pressure relief, preventing the armature assembly 4, main valve core 5, and pilot valve core 6 from getting stuck during movement.

[0078] Specifically, refer to Figure 1 and Figure 2As shown, when the first coil 21 and the second coil 22 are both de-energized, the main valve core 5 is in the middle position under the action of the elastic centering component 7, and the first oil port 31 and the fifth oil port 35 as the oil inlet are both closed by the main valve core 5 and cannot be connected with other oil ports. At this time, the high-pressure oil in the pilot oil circuit cannot enter the first pressure oil chamber p1 and the second pressure oil chamber p2; when the first coil 21 is energized, the movable iron 411 compresses the return spring 83 to the right under the action of the magnetic field force, pushing the pilot valve core 6 to move to the right. At this time, the second pressure oil chamber p2 and the oil inlet are connected to high pressure. At the same time, the oil in the first pressure oil chamber p1 enters the annular chamber b through the first oil delivery hole 53 and reaches the third oil port 33 to flow into the oil tank for pressure relief. That is, the second pressure oil chamber p2 is high pressure and the first pressure oil chamber p1 is low pressure. Due to the pressure difference, the main valve core 5 is pushed to the right to compress the centering spring 73 to move, so that the first oil port 31 is connected to the third annular chamber b4 and then to the second oil port 32. Similarly, the fourth oil port 3 4 is connected to the fifth oil port 35; when the above action is completed, the shoulder on the pilot valve core 6 and the oil delivery hole on the main valve core 5 are realigned, and the first pressure oil chamber p1 and the second pressure oil chamber p2 are closed again. At this time, due to the inertia of the main valve core 5 moving to the right, it continues to move to the right after aligning with the pilot valve core 6. At this time, the oil in the second pressure oil chamber p2 enters the annular chamber b through the second oil delivery hole 54 and reaches the third oil port 33 to flow into the oil tank for pressure relief, and the first pressure oil chamber p1 stops relief. , that is, the second pressure oil chamber p2 is at low pressure, and the first pressure oil chamber p1 is at high pressure. Due to the pressure difference, the main valve core 5 is pushed to the left, so that the main valve core 5 and the pilot valve core 6 can be automatically returned to alignment; when the first coil 21 loses power, the elastic force of the return spring 83 pushes the moving iron 411 to drive the pilot valve core 6 back to the middle position. The main valve core 5 follows the pilot valve core 6 to return to the middle position under the action of the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2. At this time, the oil ports are not connected. Similarly, when the second coil 22 is energized, the moving iron 411 drives the pilot valve core 6 to move to the left, and the main valve core 5 compresses the centering spring 73 to move to the left under the action of the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2, so that the second oil port 32 and the third oil port 33 are connected, and the fourth oil port 34 and the fifth oil port 35 are connected, realizing the reversing function of the pilot-controlled solenoid valve; when the second coil 22 loses power, at this time, the main valve core 5 and the pilot valve core 6 can automatically return to the middle position, and the aperture size of the valve hole 55 can be adjusted according to the response time of the pilot-controlled solenoid valve.

[0079] Example 2

[0080] The pilot-controlled solenoid valve provided in this embodiment is substantially the same as that in the first embodiment. The pilot-controlled solenoid valve provided in this embodiment differs from that in the first embodiment in that:

[0081] In this embodiment, if Figure 4 and Figure 5As shown, a fourth abutting portion 61 is provided on the outer peripheral wall of the connecting rod 412, and the return spring 83 is sleeved on the outer periphery of the connecting rod 412. Optionally, in this embodiment, the fourth abutting portion 61 is an abutting protrusion provided on the outer peripheral wall of the connecting rod 412.

[0082] In this embodiment, if Figure 4 and Figure 5 As shown, the second abutting portion 52 is an abutting protrusion fixedly sleeved on the outer peripheral wall of the main valve core 5.

[0083] Optionally, in this embodiment, referring to Figure 4 and Figure 5 As shown, the first oil port 31 and the fifth oil port 35 are oil unloading ports connected to the oil tank, the second oil port 32 and the fourth oil port 34 are working oil ports for connecting to the load, such as the rod chamber and the rodless chamber of the oil cylinder, and the third oil port 33 is an oil inlet connected to the oil source for providing high-pressure oil; a first annular cavity b1 and a second annular cavity b2 are provided between the pilot valve core 6 and the main valve core 5, and when the pilot valve core 6 and the main valve core 5 move relative to each other, the first annular cavity b1 can be connected to the first pressure oil chamber p1, or the second annular cavity b2 can be connected to the second pressure oil chamber p2; in addition, a first Shoulder 66, the pilot valve core 6 is also provided with a second shoulder 67 for sealing the second oil delivery hole 54, and an oil hole 6a is provided on the outer side (i.e. the right side) of the first shoulder 66, and an oil hole 6a is also provided on the outer side (i.e. the left side) of the second shoulder 67. The pilot valve core 6 is provided with an oil passage 611 in the axial direction, and the two oil holes 6a are connected with the third oil port 33 through the oil passage 611 to form a pilot oil circuit; two oil unloading holes 57 are provided on the main valve core 5, and the two oil unloading holes 57 are respectively connected with the first oil port 31 and the fifth oil port 35, and the two oil unloading holes 57 are respectively connected with the first annular cavity b1 and the second annular cavity b2.

[0084] In order to prevent the armature assembly 4, the main valve core 5 and the pilot valve core 6 from getting stuck during the movement, a first blind hole 58 is axially provided at the right end of the main valve core 5, and a first connecting hole 581 communicating with the first blind hole 58 is provided on the outer wall of the main valve core 5. The first connecting hole 581 is communicated with the first oil port 31, and the first blind hole 58, the first connecting hole 581 and the first oil port 31 cooperate to form a first pressure relief flow channel, and the oil at the first blind hole 58 returns to the oil tank through the first pressure relief flow channel to relieve pressure; at the same time, the left end of the main valve core 5 A second blind hole 59 communicating with the inner cavity of the magnetic sleeve 1 is axially provided at the end thereof, and a second connecting hole 591 communicating with the second blind hole 59 is provided on the outer wall of the main valve core 5. The second connecting hole 591 is connected to the fifth oil port 35. The second blind hole 59, the second connecting hole 591 and the fifth oil port 35 cooperate to form a second pressure relief flow channel. The oil in the magnetic sleeve 1 can be connected to the second pressure relief flow channel through the gap and return to the oil tank for pressure relief, thereby avoiding jamming of the armature assembly 4, the main valve core 5 and the pilot valve core 6 during movement.

[0085] Specifically, refer to Figure 4 and Figure 5 As shown, when the first coil 21 and the second coil 22 are both de-energized, the main valve core 5 is in the middle position under the action of the elastic centering component 7, and the third oil port 33 is the oil inlet and is closed by the main valve core 5 and cannot be connected with other oil ports. At this time, the high-pressure oil in the pilot oil circuit cannot enter the first pressure oil chamber p1 and the second pressure oil chamber p2; when the first coil 21 is energized, the moving iron 411 compresses the return spring 83 to the right under the action of the magnetic field force, pushing the pilot valve core 6 to move to the right. At this time, the pilot oil circuit is closed. The high-pressure oil enters the second pressure oil chamber p2. At the same time, the oil in the first pressure oil chamber p1 enters the second annular chamber b2 through the oil hole 6a and reaches the first oil port 31 to flow into the oil tank for pressure relief. That is, the second pressure oil chamber p2 is at high pressure, and the first pressure oil chamber p1 is at low pressure. Due to the pressure difference, the main valve core 5 is pushed to the right and the centering spring 73 is compressed to move to the right, so that the first oil port 31 is connected to the third annular chamber b4 and then to the second oil port 32. Similarly, the fourth oil port 34 is connected to the fifth oil port. When the above action is completed, the shoulder on the pilot valve core 6 and the oil delivery hole on the main valve core 5 are realigned, and the first pressure oil chamber p1 and the second pressure oil chamber p2 are closed again. At this time, due to the inertia of the main valve core 5 moving to the right, it continues to move to the right after aligning with the pilot valve core 6. At this time, the high-pressure oil in the pilot oil circuit enters the first pressure oil chamber p1, and the oil in the second pressure oil chamber p2 enters the first annular chamber b1 through the oil hole 6a to reach the fourth oil port 34 and flows into the oil tank for Pressure relief, that is, the second pressure oil chamber p2 is at low pressure, and the first pressure oil chamber p1 is at high pressure. Due to the pressure difference, the main valve core 5 is pushed to the left, so that the main valve core 5 and the pilot valve core 6 can be automatically returned to alignment; when the first coil 21 loses power, the elastic force of the return spring 83 pushes the moving iron 411 to drive the pilot valve core 6 back to the middle position, and the main valve core 5 follows the pilot valve core 6 to return to the middle position under the action of the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2. At this time, the oil ports are not connected. Similarly, when the second coil 22 is energized, the moving iron 411 drives the pilot valve core 6 to move to the left, and the main valve core 5 moves to the left under the action of the pressure difference between the first pressure oil chamber p1 and the second pressure oil chamber p2, so that the second oil port 32 and the third oil port 33 are connected, and the fourth oil port 34 and the fifth oil port 35 are connected, realizing the reversing function of the pilot-controlled solenoid valve; when the second coil 22 loses power, at this time, the main valve core 5 and the pilot valve core 6 can automatically return to the middle position, and the aperture size of the oil hole 6a can be adjusted according to the response time of the solenoid valve.

[0086] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A pilot-controlled solenoid valve, characterized in that: include: Magnetic conductive sleeve (1); A coil (2), wherein the coil (2) is sleeved on the outer periphery of the magnetic conductive sleeve (1); A valve sleeve (3), the valve sleeve (3) being connected to the end of the magnetic sleeve (1), and the valve sleeve (3) being provided with a plurality of oil ports at intervals; An armature assembly (4), the armature assembly (4) comprising a movable iron piece (41), the movable iron piece (41) being inserted into the magnetic sleeve (1) and being capable of moving relative to the magnetic sleeve (1) along the axial direction of the magnetic sleeve (1) in response to the electromagnetic force generated by the coil (2); A main valve core (5) is inserted into the valve sleeve (3) and can move relative to the valve sleeve (3) along the axial direction of the valve sleeve (3) to connect or block the plurality of oil ports. The valve sleeve (3) and the main valve core (5) cooperate to form a first pressure oil chamber (p1) and a second pressure oil chamber (p2). The pressure difference between the first pressure oil chamber (p1) and the second pressure oil chamber (p2) can drive the main valve core (5) to move. A pilot valve core (6) is inserted into the main valve core (5), and the pilot valve core (6) is fixedly connected to the movable iron member (41). When the movable iron member (41) drives the pilot valve core (6) to move relative to the main valve core (5), the pressure difference between the first pressure oil chamber (p1) and the second pressure oil chamber (p2) can be adjusted; as well as an elastic centering component (7) disposed on the main valve core (5), wherein the elastic centering component (7) is configured to always have a tendency to hinder the main valve core (5) from moving relative to the valve sleeve (3); A first abutting portion (51) and a second abutting portion (52) are provided on the outer peripheral wall of the main valve core (5), and the first abutting portion (51) and the second abutting portion (52) are arranged at intervals along the axial direction of the main valve core (5); The armature assembly (4) further includes an iron stop (42) fixedly disposed in the magnetic conductive sleeve (1); The elastic centering component (7) includes a first limiting ring (71), a second limiting ring (72) and a centering spring (73), the first limiting ring (71) and the second limiting ring (72) are both sleeved on the outer periphery of the main valve core (5), the first limiting ring (71) and the second limiting ring (72) are arranged at intervals along the axial direction of the main valve core (5), the side of the first limiting ring (71) away from the second limiting ring (72) can abut against the stop iron (42), and the first limiting ring (71) away from the second limiting ring (7 2) abuts against the first abutting portion (51), a side of the second limiting ring (72) away from the first limiting ring (71) can abut against the valve sleeve (3), and a side of the second limiting ring (72) away from the first limiting ring (71) abuts against the second abutting portion (52), the centering spring (73) is sleeved on the outer periphery of the main valve core (5), a first end of the centering spring (73) abuts against the first limiting ring (71), and a second end of the centering spring (73) abuts against the second limiting ring (72); The pilot-controlled solenoid valve further comprises: An elastic reset component (8) is configured to always have a tendency to hinder the movement of the pilot valve core (6).

2. The pilot-controlled solenoid valve according to claim 1, characterized in that: The first abutment portion (51) is an abutment protrusion fixedly sleeved on the outer peripheral wall of the main valve core (5), or the first abutment portion (51) is a positioning shoulder provided on the outer peripheral wall of the main valve core (5); The second abutting portion (52) is an abutting protrusion fixedly sleeved on the outer peripheral wall of the main valve core (5), or the second abutting portion (52) is a positioning shoulder provided on the outer peripheral wall of the main valve core (5).

3. The pilot-controlled solenoid valve according to claim 1, characterized in that: The movable iron member (41) comprises: A movable iron (411), wherein the movable iron (411) and the stop iron (42) are arranged at intervals along the axial direction of the main valve core (5), and the stop iron (42) can abut against the movable iron (411) to limit the limit position of the movable iron (411) moving relative to the magnetic sleeve (1) toward the valve sleeve (3); and A connecting rod (412), wherein a first end of the connecting rod (412) is connected to the inner cavity of the movable iron (411), a second end of the connecting rod (412) is passed through the inner cavity of the stop iron (42), and the second end of the connecting rod (412) is fixedly connected to the pilot valve core (6).

4. The pilot-controlled solenoid valve according to claim 3, characterized in that: A third abutting portion (4121) is provided on the outer peripheral wall of the connecting rod (412), and a fourth abutting portion (61) is provided on the outer peripheral wall of the pilot valve core (6) or the outer peripheral wall of the connecting rod (412), and the third abutting portion (4121) and the fourth abutting portion (61) are arranged at intervals along the axial direction of the pilot valve core (6); The elastic reset assembly (8) includes a third limiting ring (81), a fourth limiting ring (82) and a reset spring (83), wherein the third limiting ring (81) and the fourth limiting ring (82) are arranged at intervals along the axial direction of the pilot valve core (6), and the third limiting ring (81) is sleeved on the outer periphery of the connecting rod (412), and the side of the third limiting ring (81) away from the fourth limiting ring (82) can abut against the stop iron (42), and the side of the third limiting ring (81) away from the fourth limiting ring (82) can abut against the third abutting portion (4121), the fourth limiting ring (82) is sleeved on the outer periphery of the pilot valve core (6) or the connecting rod (412), the side of the fourth limiting ring (82) away from the third limiting ring (81) can abut against the stop iron (42), and the side of the fourth limiting ring (82) away from the third limiting ring (81) abuts against the fourth abutting portion (61), the first end of the return spring (83) abuts against the third limiting ring (81), and the second end of the return spring (83) abuts against the fourth limiting ring (82).

5. The pilot-controlled solenoid valve according to any one of claims 1 to 4, characterized in that: The valve sleeve (3) is provided with a first oil port (31), a second oil port (32), a third oil port (33), a fourth oil port (34) and a fifth oil port (35) in sequence along its axial direction; The main valve core (5) is provided with a first oil delivery hole (53) communicating with the first pressure oil chamber (p1), and the main valve core (5) is also provided with a second oil delivery hole (54) communicating with the second pressure oil chamber (p2); The pilot valve core (6) is provided with a pilot oil circuit, and the pilot oil circuit is connected to or blocked from the first pressure oil chamber (p1) when the pilot valve core (6) moves relative to the main valve core (5), and the pilot oil circuit is connected to or blocked from the second pressure oil chamber (p2) when the pilot valve core (6) moves relative to the main valve core (5).

6. The pilot-controlled solenoid valve according to claim 5, characterized in that: The first oil port (31) and the fifth oil port (35) are oil inlet ports, the second oil port (32) and the fourth oil port (34) are working oil ports, and the third oil port (33) is an oil discharge port; An annular cavity (b) is provided between the main valve core (5) and the pilot valve core (6), the annular cavity (b) being communicable with the first pressure oil cavity (p1) or the second pressure oil cavity (p2), and shoulders at both ends of the annular cavity (b) being used to seal the first oil delivery hole (53) and the second oil delivery hole (54), respectively; The pilot valve core (6) is provided with a first channel (63) and a second channel (64) at both ends along its axial direction, and the first channel (63), the second channel (64) and the annular cavity (b) are connected to form the pilot oil circuit; A valve hole (55) communicating with the first pressure oil chamber (p1) and the second pressure oil chamber (p2) is formed in the side wall of the main valve core (5) along its axial direction, and the valve hole (55) is communicated with the oil inlet.

7. The pilot-controlled solenoid valve according to claim 6, characterized in that: The first channel (63), the annular cavity (b) and the oil unloading port are connected to form a first pressure relief flow channel; An oil inlet hole (65) is provided at the end of the pilot valve core (6) along its radial direction and is connected to the inner cavity of the magnetic sleeve (1). The oil inlet hole (65) is connected to the second channel (64). The oil inlet hole (65), the second channel (64), the annular cavity (b) and the oil unloading port are connected to form a second pressure relief flow channel.

8. The pilot-controlled solenoid valve according to claim 5, characterized in that: The valve sleeve (3) and the main valve core (5) cooperate to form a third annular cavity (b4) and a fourth annular cavity (b5); a connecting boss (56) is provided between the third annular cavity (b4) and the fourth annular cavity (b5); a connecting hole (561) for connecting the third oil port (33) and the pilot oil circuit is provided on the connecting boss (56); When the main valve core (5) moves, the third annular cavity (b4) can connect the second oil port (32) to or block the first oil port (31), the third annular cavity (b4) can connect the second oil port (32) to or block the third oil port (33), the fourth annular cavity (b5) can connect the fourth oil port (34) to or block the third oil port (33), and the fourth annular cavity (b5) can connect the fourth oil port (34) to or block the fifth oil port (35).

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