阅读说明：本技术 一种先导式控制阀 (Pilot-operated control valve ) 是由 张玺 武正 宋学洋 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种先导式控制阀,该先导式控制阀包括：阀体,电磁阀,弹簧阀以及补气通道；在所述电磁阀通电时,所述电磁阀打开所述过气通道的第一端,所述弹簧阀打开所述过气通道的第二端,所述进气口与所述出气口导通；在所述电磁阀断电时,所述电磁阀关闭所述过气通道的第一端,所述弹簧阀关闭所述过气通道的第二端,所述进气口与所述出气口关断。如此设置,可以通过电磁阀的通断电以及电磁阀和弹簧阀之间气体压力的双重作用,来实现弹簧阀的开启和关闭,从而实现先导式控制阀的开启与关闭。本实施例所要保护的技术方案能够明显降低系统重量和功耗,以及能够实现多次工作,从而能够大幅延长先导式控制阀的使用寿命。(The invention discloses a pilot-operated control valve, which comprises: the valve body, the electromagnetic valve, the spring valve and the air supplementing channel; when the electromagnetic valve is electrified, the electromagnetic valve opens the first end of the air passing channel, the spring valve opens the second end of the air passing channel, and the air inlet is communicated with the air outlet; when the electromagnetic valve is powered off, the electromagnetic valve closes the first end of the air passing channel, the spring valve closes the second end of the air passing channel, and the air inlet and the air outlet are shut off. So set up, can realize opening and closing of spring valve through the dual function of the break-make electricity of solenoid valve and gas pressure between solenoid valve and the spring valve to realize opening and closing of guide's formula control valve. The technical scheme to be protected by the embodiment can obviously reduce the weight and the power consumption of the system and can realize multiple operations, so that the service life of the pilot control valve can be greatly prolonged.)

1. A pilot operated control valve, comprising:

the valve body (2) comprises a first cavity and a second cavity which are adjacently arranged; the first cavity and the second cavity are communicated through a gas passage (23); the valve body (2) further comprises an air inlet (1) and an air outlet (14), the air inlet (1) is communicated with the second cavity, and the air outlet (14) is communicated with the air passing channel (23);

the electromagnetic valve is arranged in the first cavity, the electromagnetic valve core (13) is arranged close to the air passing channel (23), and an electromagnetic valve cavity (22) is arranged between the electromagnetic valve core (13) and the air passing channel (23);

a spring valve disposed in the second cavity; a spring valve cavity (21) is arranged between the spring valve core (17) and the valve seat (20), and the spring valve core (17) is arranged close to the air passing channel (23); the spring valve core (17) is in clearance fit with the second cavity, and the gas supplementing rate of high-pressure gas for supplementing gas to the spring valve cavity (21) through a clearance is smaller than the gas outlet rate of high-pressure gas for exhausting gas outwards through the gas passage (23);

an air supply passage (16) provided in the valve body (2); the air supply channel (16) is used for communicating the electromagnetic valve chamber (22) with the spring valve chamber (21);

when the electromagnetic valve is electrified, the electromagnetic valve opens the first end of the air passing channel (23), the spring valve opens the second end of the air passing channel (23), and the air inlet (1) is communicated with the air outlet (14); when the electromagnetic valve is powered off, the electromagnetic valve closes the first end of the air passing channel (23), the spring valve closes the second end of the air passing channel (23), and the air inlet (1) and the air outlet (14) are closed.

2. The pilot-operated control valve according to claim 1, wherein the solenoid valve includes:

a solenoid valve housing (4) disposed in the first cavity; the solenoid valve shell (4) is provided with a mounting cavity suitable for mounting a solenoid valve core (13);

the electromagnet is arranged on the electromagnetic valve shell (4); an iron core (7) of the electromagnet is arranged in the mounting cavity;

the solenoid valve core (13) is arranged in the mounting cavity; the electromagnetic valve core (13) is connected with the electromagnet through an elastic piece.

3. Piloted control valve according to claim 2, characterized in that a first seal (3) is provided between the solenoid housing (4) and the first cavity.

4. Piloted control valve as in claim 2, characterized in that a second seal (9) is provided between the core (7) of the electromagnet and the mounting cavity.

5. Pilot control valve according to any one of claims 2-4, characterized in that the solenoid housing (4) is provided with a through hole at the top, and that the end of the solenoid core (7) remote from the solenoid valve spool (13) has an extension adapted to protrude from the through hole, which extension is connected with the solenoid housing (4) by a fixing element.

6. Pilot control valve according to claim 5, characterized in that the fixing element is a compression nut (8), the compression nut (8) having a first thread on its inside and the extension having a second thread cooperating with the first thread, the compression nut (8) being adapted to fix the core (7) of the electromagnet to the solenoid housing (4) by means of the first and second threads.

7. Pilot control valve according to one of claims 2 to 4, characterized in that an electronic connection (10) is provided on the solenoid valve housing (4), which electronic connection (10) is adapted to receive a control signal.

8. The pilot operated control valve according to any one of claims 2 to 4, wherein the spring valve further comprises:

a current-limiting ring (18);

the mounting groove is formed in the circumferential end face, close to the second cavity, of the spring valve core (17); the mounting groove is suitable for mounting the current limiting ring (18); the flow limiting ring (18) is in interference fit with the second cavity.

9. Piloted control valve as in claim 8, wherein said restrictor ring (18) is cut to form a notch (181), said notch (181) comprising a first edge and a second edge in mutual engagement, said first edge and said second edge being in an overlapping mortise and tenon configuration.

10. Piloted control valve as in claim 8, characterized in that said spring spool (17) is provided with two said flow restrictor rings (18), the notches (181) of said two flow restrictor rings (18) being arranged opposite each other.

11. Piloted control valve as in claim 9 or 10, characterized in that said restrictor ring (18) is coated with a corrugated strip (24), said corrugated strip (24) being made of elastic alloy 3J 1.

12. Piloted control valve as in claim 9 or 10, characterized in that a third seal (19) is provided between the valve seat (20) of the spring valve and the second chamber.

Technical Field

The invention relates to the technical field of control valves of liquid rocket engine systems, in particular to a pilot-operated control valve.

Background

With the accelerated development of the aerospace industry, technicians have higher and higher requirements on the reliability and economy of a launch vehicle engine. To reduce the cost of a single launch and to reuse the rocket, higher demands are made on the solenoid valves in the system. Solenoid valves are commonly used as control valves for liquid rocket engine system control gases and for blow-off gases, as well as isolation valves for engine system starting gas cylinders, booster delivery system gas cylinders, and cold gas engine system high pressure gas cylinders.

At present, there are three solutions, the traditional solution one: the electric explosion valve with good sealing performance and reliable work is adopted, but the electric explosion valve is a valve which works once, cannot meet the requirement of multiple starting, cannot be reused, and increases the use cost; the traditional solution two: the direct-acting electromagnetic valve is adopted, but the electromagnetic valve with a large drift diameter can be opened only by larger electromagnetic force, so that the electromagnetic coil has heavy weight, high power consumption and large heat productivity, the takeoff weight and the controller load of the rocket are increased, the service life of the valve is short, and the valve is not suitable for a reusable rocket engine; the traditional solution is three: the pilot-operated pneumatic control valve is adopted, so that although the pilot-operated pneumatic control valve is suitable for a reusable rocket engine, an additional control gas circuit and a control medium are required, the structure is complex, and the risk of leakage of a system pipeline is increased.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to provide a pilot operated control valve with a long service life, low system weight and low power consumption.

To achieve the above object, an embodiment of the present invention provides a pilot-operated control valve including: the valve body comprises a first cavity and a second cavity which are adjacently arranged; the first cavity and the second cavity are communicated through an air passage; the valve body further comprises an air inlet and an air outlet, the air inlet is communicated with the second cavity, and the air outlet is communicated with the air passing channel; the electromagnetic valve is arranged in the first cavity, the electromagnetic valve core is arranged close to the gas passing channel, and an electromagnetic valve cavity is arranged between the electromagnetic valve core and the gas passing channel; a spring valve disposed in the second cavity; a spring valve cavity is arranged between the spring valve core and the valve seat, and the spring valve core is arranged close to the air passing channel; the spring valve core is in clearance fit with the second cavity, and the gas supplementing rate of high-pressure gas for supplementing gas to the spring valve cavity through the clearance is smaller than the gas outlet rate of high-pressure gas for exhausting gas outwards through the gas passage; the air replenishing channel is arranged in the valve body; the air supplementing channel is used for communicating the electromagnetic valve chamber with the spring valve chamber; when the electromagnetic valve is electrified, the electromagnetic valve opens the first end of the air passing channel, the spring valve opens the second end of the air passing channel, and the air inlet is communicated with the air outlet; when the electromagnetic valve is powered off, the electromagnetic valve closes the first end of the air passing channel, the spring valve closes the second end of the air passing channel, and the air inlet and the air outlet are shut off.

Optionally, the solenoid valve comprises: a solenoid housing disposed in the first cavity; the solenoid valve shell is provided with a mounting cavity suitable for mounting a solenoid valve core; the electromagnet is arranged on the electromagnetic valve shell; the iron core of the electromagnet is arranged in the mounting cavity; the electromagnetic valve core is arranged in the mounting cavity; the electromagnetic valve core is connected with the electromagnet through an elastic piece.

Optionally, a first seal is disposed between the solenoid housing and the first cavity.

Optionally, a second sealing element is arranged between the iron core of the electromagnet and the installation cavity.

Optionally, the solenoid valve housing is provided with a through hole at the top, one end of the iron core of the electromagnet, which is far away from the solenoid valve core, is provided with an extending portion, the extending portion is suitable for extending out of the through hole, and the extending portion is connected with the solenoid valve housing through a fixing member.

Optionally, the fixing member is a compression nut, the inner side of the compression nut has a first thread, the protruding portion has a second thread matching with the first thread, and the compression nut is adapted to fix the iron core of the electromagnet to the electromagnetic valve housing through the first thread and the second thread.

Optionally, an electronic connection end is arranged on the solenoid valve housing, and the electronic connection end is suitable for receiving a control signal.

Optionally, the spring valve further comprises: a current-limiting ring; the mounting groove is formed in the circumferential end face, close to the second cavity, of the spring valve core; the mounting groove is suitable for mounting the current limiting ring; the flow limiting ring and the second cavity are in interference fit.

Optionally, the current-limiting ring forms a notch by cutting, the notch includes a first edge and a second edge that are fitted with each other, and the first edge and the second edge are in a tenon-and-mortise structure that is overlapped with each other.

Optionally, the spring valve core is provided with two flow limiting rings, and notches of the two flow limiting rings are arranged oppositely.

Optionally, a corrugated belt is laid on the current limiting ring, and the corrugated belt is made of elastic alloy 3J 1.

Optionally, a third seal is provided between the valve seat of the spring valve and the second chamber.

Compared with the prior art, the technical scheme of the invention has the following advantages:

1. an embodiment of the present invention provides a pilot-operated control valve, including: the valve body comprises a first cavity and a second cavity which are adjacently arranged; the first cavity and the second cavity are communicated through an air passage; the valve body further comprises an air inlet and an air outlet, the air inlet is communicated with the second cavity, and the air outlet is communicated with the air passing channel; the electromagnetic valve is arranged in the first cavity, the electromagnetic valve core is arranged close to the gas passing channel, and an electromagnetic valve cavity is arranged between the electromagnetic valve core and the gas passing channel; a spring valve disposed in the second cavity; a spring valve cavity is arranged between the spring valve core and the valve seat, and the spring valve core is arranged close to the air passing channel; the spring valve core is in clearance fit with the second cavity, and the gas supplementing rate of high-pressure gas for supplementing gas to the spring valve cavity through the clearance is smaller than the gas outlet rate of high-pressure gas for exhausting gas outwards through the gas passage; the air replenishing channel is arranged in the valve body; the air supplementing channel is used for communicating the electromagnetic valve chamber with the spring valve chamber; when the electromagnetic valve is electrified, the electromagnetic valve opens the first end of the air passing channel, the spring valve opens the second end of the air passing channel, and the air inlet is communicated with the air outlet; when the electromagnetic valve is powered off, the electromagnetic valve closes the first end of the air passing channel, the spring valve closes the second end of the air passing channel, and the air inlet and the air outlet are shut off.

So set up, can realize opening and closing of spring valve through the dual function of the break-make electricity of solenoid valve and gas pressure between solenoid valve and the spring valve to realize opening and closing of guide's formula control valve. Compared with the prior art in which only the solenoid valve is arranged and the control gas path and the control medium are arranged, the technical scheme to be protected in the embodiment can obviously reduce the weight and the power consumption of the system, and does not need a large solenoid coil of the solenoid valve with a large drift diameter. Compared with the one-time operation of the electric storm valve in the prior art, the technical scheme to be protected by the embodiment can realize multiple operations, so that the service life of the pilot control valve can be greatly prolonged.

2. According to the embodiment of the invention, the flow limiting ring is cut with the notch, and the first edge and the second edge are in the mutually overlapped tenon-and-mortise structures, so that the air supplementing rate of high-pressure air to the spring valve cavity through the gap can be limited, the air supplementing rate of the high-pressure air to the spring valve cavity through the gap is ensured to be smaller than the air outlet rate of the high-pressure air to the outside through the air passage, and the normal opening and closing of the pilot-operated control valve is further ensured.

3. The embodiment of the invention is characterized in that a corrugated belt is laid on the current limiting ring, and the corrugated belt is made of elastic alloy 3J 1. The compensation effect of the elastic alloy ensures that the current-limiting ring still keeps good current-limiting effect at lower temperature.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for a worker of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic view of a pilot operated control valve of an embodiment of the present invention in a first orientation in a closed state;

FIG. 2 is a schematic diagram of a pilot operated control valve in a second orientation in a closed state in accordance with an embodiment of the present invention;

FIG. 3 is a schematic diagram of a pilot operated control valve in a first orientation in an open state in accordance with an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a current-limiting ring according to an embodiment of the present invention;

FIG. 5 is a schematic view of a slit of a current-limiting ring according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a corrugated strip in accordance with an embodiment of the present invention.

Reference numerals:

1-air inlet, 2-valve body, 3-first sealing element, 4-electromagnetic valve shell, 5-coil component, 6-armature, 7-iron core, 8-compression nut, 9-second sealing element, 10-electronic connecting end, 11-electromagnetic valve spring, 12-yoke, 13-electromagnetic valve core, 14-air outlet,

15-spring of spring valve, 16-air supply channel, 17-spring valve core, 18-flow-limiting ring, 181-notch, 19-third sealing element, 20-valve seat, 21-spring valve chamber, 22-solenoid valve chamber, 23-air passage and 24-corrugated strip.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a worker skilled in the art without creative efforts based on the embodiments of the present invention, belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases by a worker of ordinary skill in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

With the accelerated development of the aerospace industry, technicians have higher and higher requirements on the reliability and economy of a launch vehicle engine. To reduce the cost of a single launch and to reuse the rocket, higher demands are made on the solenoid valves in the system. Solenoid valves are commonly used as control valves for liquid rocket engine system control gases and for blow-off gases, as well as isolation valves for engine system starting gas cylinders, booster delivery system gas cylinders, and cold gas engine system high pressure gas cylinders.

At present, there are three solutions, the traditional solution one: the electric explosion valve with good sealing performance and reliable work is adopted, but the electric explosion valve is a valve which works once, cannot meet the requirement of multiple starting, cannot be reused, and increases the use cost; the traditional solution two: the direct-acting electromagnetic valve is adopted, but the electromagnetic valve with a large drift diameter can be opened only by larger electromagnetic force, so that the electromagnetic coil has heavy weight, high power consumption and large heat productivity, the takeoff weight and the controller load of the rocket are increased, the service life of the valve is short, and the valve is not suitable for a reusable rocket engine; the traditional solution is three: the pilot-operated pneumatic control valve is adopted, although the pilot-operated pneumatic control valve is suitable, the risk of leakage of a system pipeline is increased.

Therefore, the technology to be solved by the invention can repeatedly use the rocket engine, but needs additional control gas circuit and control medium, and has the technical problem of complex structure, and the invention aims to provide a pilot-operated control valve with long service life, low system weight and low power consumption.

As shown in fig. 1 to 3, the embodiment of the present invention provides a pilot-operated control valve, which includes a valve body 2, a solenoid valve, a spring valve, and an air supply passage 16.

The valve body 2 comprises a first cavity and a second cavity which are adjacently arranged, and the first cavity is communicated with the second cavity through an air passage 23. The valve body 2 further comprises an air inlet 1 and an air outlet 14, the air inlet 1 is communicated with the second cavity, and the air outlet 14 is communicated with the air passing channel 23.

The solenoid valve is arranged in the first cavity, the solenoid valve core 13 is arranged close to the air passing channel 23, and a solenoid valve chamber 22 is arranged between the solenoid valve core 13 and the air passing channel 23.

The spring valve is arranged in the second cavity, a spring valve cavity 21 is arranged between the spring valve core 17 and the valve seat 20, the spring valve core 17 is arranged close to the air passing channel 23, and the spring valve core 17 is arranged at one end, far away from the air passing channel 23, of the second cavity. The spring valve core 17 is in clearance fit with the second cavity, and the air supply rate of supplying air to the spring valve cavity 21 through the clearance by high-pressure air needs to be controlled to be smaller than the air outlet rate of the high-pressure air outwards through the air passage 23.

And the air supplementing channel 16 is arranged in the valve body 2, and the air supplementing channel 16 is used for communicating the electromagnetic valve chamber 22 with the spring valve chamber 21.

When the pilot-operated control valve needs to be controlled to be opened, the electromagnetic valve is firstly controlled to be electrified. When the electromagnetic valve is electrified, the electromagnetic valve controls the electromagnetic valve core 13 to be away from the air passing channel 23, and the electromagnetic valve core 13 compresses the electromagnetic valve spring 11, so that the first end of the air passing channel 23 is opened. Meanwhile, after the solenoid valve opens the gas passing channel 23, the gas supplementing channel 16 communicates the solenoid valve chamber 22 with the spring valve chamber 21, so that the high-pressure gas in the solenoid valve chamber 22 and the spring valve chamber 21 is rapidly discharged outwards through the gas passing channel 23. Because the gas supply rate of the high-pressure gas to the spring valve chamber 21 through the gap is less than the gas discharge rate of the high-pressure gas to the outside through the gas passage 23, the upper side and the lower side of the spring valve core 17 form a gas pressure difference, the spring valve core 17 overcomes the elasticity, the self weight and the friction force of the spring 15 of the spring valve under the action of the gas pressure difference, and the spring valve opens the second end of the gas passage 23, so that the gas inlet 1 is communicated with the gas outlet 14, and the pilot-operated control valve is opened.

According to the same principle, when the pilot control valve needs to be controlled to be closed, the electromagnetic valve is controlled to be powered off firstly. When the electromagnetic valve is powered off, the electromagnetic valve core 13 and the electromagnetic valve spring 11 are reset, namely, the electromagnetic valve core 13 moves towards the direction close to the air passing channel 23, so that the first end of the air passing channel 23 is closed. Meanwhile, after the electromagnetic valve closes the gas passing channel 23, the gas supplementing channel 16 communicates the electromagnetic valve chamber 22 with the spring valve chamber 21, so that the gas pressure in the spring valve chamber 21 gradually rises, and the spring valve 17 closes the second end of the gas passing channel 23 under the action of the elastic force of the spring 15 of the spring valve and the pressure difference between the upper side and the lower side of the spring valve 17, so that the gas inlet 1 is disconnected from the gas outlet 14, and the pilot-operated control valve is closed.

So set up, can realize opening and closing of spring valve through the dual function of the break-make electricity of solenoid valve and gas pressure between solenoid valve and the spring valve to realize opening and closing of guide's formula control valve. Compared with the prior art in which only the solenoid valve is arranged and the control gas path and the control medium are arranged, the technical scheme to be protected in the embodiment can obviously reduce the weight and the power consumption of the system, and does not need a large solenoid coil of the solenoid valve with a large drift diameter. Compared with the one-time operation of the electric storm valve in the prior art, the technical scheme to be protected by the embodiment can realize multiple operations, so that the service life of the pilot control valve can be greatly prolonged.

Alternatively, in the embodiment of the present invention, the solenoid valve includes a solenoid valve housing 4, an electromagnet, and a solenoid valve core 13. Specifically, the solenoid valve housing 4 is disposed in the first cavity, and the solenoid valve housing 4 has a mounting cavity adapted to mount the solenoid spool 13. The electromagnet is arranged on the electromagnetic valve shell 4, and an iron core 7 of the electromagnet is arranged in the installation cavity. The solenoid valve core 13 is arranged in the installation cavity, and the solenoid valve core 13 is connected with the electromagnet through a solenoid valve spring 11. The coil block 5 is wound on the solenoid valve housing 4. The yoke 12 is provided outside the coil. The solenoid valve core is connected with a solenoid valve spring through an armature 6.

Optionally, in the embodiment of the present invention, a first sealing member 3 is disposed between the solenoid valve housing 4 and the first cavity. And a second sealing member 9 can be arranged between the iron core 7 of the electromagnet and the mounting cavity.

Further, in the embodiment of the present invention, the solenoid valve housing 4 is provided with a through hole at the top, and one end of the iron core 7 of the electromagnet away from the solenoid valve core 13 has an extending portion, the extending portion is adapted to extend from the through hole, and the extending portion is connected with the solenoid valve housing 4 through a fixing member. Specifically, the fixing member is a compression nut 8, a first thread is arranged on the inner side of the compression nut 8, a second thread matched with the first thread is arranged on the protruding portion, and the compression nut 8 is suitable for fixing the iron core 7 of the electromagnet on the solenoid valve shell 4 through the first thread and the second thread.

Of course, the embodiment of the present invention is only to illustrate the type of the fixing element, and is not limited thereto, and those skilled in the art can change the fixing element according to actual situations, and can achieve the same technical effect.

Optionally, in the embodiment of the present invention, an electronic connection 10 is disposed on the solenoid valve housing 4, and the electronic connection 10 is adapted to receive a control signal. The electromagnetic valve can be connected with a controller through the electronic connecting end 10, and the controller controls the opening and closing of the electromagnetic valve through the electronic connecting end 10.

Further, in the present embodiment, the spring valve further includes a restrictor ring 18 and a mounting groove. Specifically, a mounting groove is formed in the circumferential end face, close to the second cavity, of the spring valve core 17, the mounting groove is suitable for mounting the flow limiting ring 18, and the flow limiting ring 18 and the second cavity are in interference fit.

In addition, in the embodiment of the present invention, the current-limiting ring 18 may be cut to form a notch 181, where the notch 181 includes a first edge and a second edge that are engaged with each other, and the first edge and the second edge are in a tenon-and-mortise structure that is overlapped with each other. The spring valve core 17 is provided with two flow limiting rings 18, and the notches 181 of the two flow limiting rings 18 are arranged oppositely.

Of course, a plurality of current-limiting rings 18, for example, three, four, etc., may be disposed on the spring valve core 17, and this embodiment merely illustrates the number of the current-limiting rings 18, but the number is not limited thereto, and those skilled in the art may change the number of the current-limiting rings 18 according to actual situations, and may achieve the same technical effect.

In the embodiment of the invention, the cut 181 is cut on the flow-limiting ring 18, and the first edge and the second edge are in the mutually overlapped tenon-and-mortise structures, so that the air supplement rate of high-pressure air to the spring valve cavity 21 through the gap can be limited, and the air supplement rate of the high-pressure air to the spring valve cavity 21 through the gap is ensured to be smaller than the air outlet rate of the high-pressure air to the outside through the air passage 23, thereby ensuring the normal opening and closing of the pilot-operated control valve.

Optionally, in the embodiment of the present invention, as shown in fig. 6, a corrugated strip made of elastic alloy 3J1 is applied on the current-limiting ring 18. Fig. 6 is a side view on the left side and fig. 6 is a front view on the right side. The embodiment of the invention is characterized in that a corrugated belt is laid on the current limiting ring 18 and is made of elastic alloy 3J 1. As shown in fig. 5, as another embodiment, the cut 181 of the current-limiting ring 18 is made by 22 ° cutting, and the compensation effect of the elastic alloy ensures that the current-limiting ring 18 still maintains good current-limiting effect at lower temperature.

Optionally, in the present embodiment, a third sealing member is disposed between the valve seat 20 of the spring valve and the second cavity.

Of course, the types of the first sealing member 3, the second sealing member 9 and the third sealing member may be changed by those skilled in the art according to actual situations, and the embodiment of the present invention is only for illustration and not for limitation, and can achieve the same technical effects.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Variations and modifications in other variations may occur to those skilled in the art based upon the foregoing description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.