CN210920179U

CN210920179U - Valve structure and liquid engine

Info

Publication number: CN210920179U
Application number: CN201921186828.5U
Authority: CN
Inventors: 陈涛; 王喜良; 张思远; 刘耀林; 李莹; 张航; 薛海龙
Original assignee: Landspace Technology Co Ltd
Current assignee: Landspace Technology Co Ltd
Priority date: 2019-07-26
Filing date: 2019-07-26
Publication date: 2020-07-03
Anticipated expiration: 2029-07-26

Abstract

The utility model provides a valve structure and liquid engine. The valve structure comprises a main body unit, an actuating unit, an executing unit and a holding unit; the main body unit comprises a medium inlet and a medium outlet for liquid to enter and flow out and a medium channel communicated with the medium inlet and the medium outlet, the actuating unit is used for driving the executing unit to move in the medium channel, so that the executing unit enables the medium inlet to be opened or closed, and the retaining unit is used for retaining the executing unit to enable the medium inlet to be kept at a working position. The utility model discloses a valve structure and liquid engine can keep execution unit in original position through keeping the unit to valve structure need not continue to let in control gas and can keep at the work position, realizes the on-off control to the propellant access & exit promptly with less control gas quantity, improves liquid engine's working property.

Description

Valve structure and liquid engine

Technical Field

The utility model relates to a liquid rocket engine's valve technical field especially relates to a valve structure and liquid engine.

Background

The valve is an important part for realizing the starting and shutdown of the liquid rocket engine. The medium of the low-temperature liquid rocket engine is an ultralow-temperature propellant, the medium temperature range is usually about 20K-120K, and the pressure is more than 10 MPa. The valve operating gas is usually a high-pressure gas having a pressure of about 20 MPa.

The liquid propellant used by the existing domestic active low-temperature liquid rocket engine comprises liquid hydrogen and liquid oxygen, and liquid methane is adopted as the propellant in some domestic research models. As a novel ultralow-temperature propellant, the temperature zone of the liquid methane propellant is also 20K-120K, and the pressure of the propellant is more than 10 MPa.

Dynamic seals for valves used in liquid engines using conventional cryogenic propellants are typically metal bellows solutions and precious metal coatings. The valve can be turned on and off through the action of the high-pressure helium gas, and after the valve acts in place, the control gas needs to be continuously introduced to keep the current state of the valve, so that the working reliability of the valve is reduced.

It is highly desirable to provide a valve structure suitable for use in low temperature environments and having a condition-maintaining function, thereby providing a foundation for the use of liquid oxymethane propellants in liquid launch vehicles.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art not enough, provide a valve structure and liquid engine. The valve structure can be well suitable for a low-temperature liquid rocket engine, and the using amount of engine control gas is reduced on the premise of reliably sealing the control gas and the liquid propellant.

One aspect of the present invention provides a valve structure, including a main body unit, an actuating unit, an executing unit and a holding unit; the main body unit comprises a medium inlet and a medium outlet for liquid to enter and flow out and a medium channel communicated with the medium inlet and the medium outlet, the actuating unit is used for driving the executing unit to move in the medium channel, so that the executing unit enables the medium inlet to be opened or closed, and the retaining unit is used for retaining the executing unit to enable the medium inlet to be kept at a working position.

In one embodiment, the main body unit comprises a main body part with a through hole along a first direction, the actuating unit comprises an actuating cylinder which is used for being connected with one end of the main body part in a sealing mode in the first direction, the executing unit comprises a valve which is arranged on the main body part and located on the inner side of the second opening hole, and the retaining unit comprises an elastic piece which is arranged on the valve in a compression mode and is far away from the actuating side;

the through hole includes a first opening and a second opening formed inward at both ends of the main body in the first direction, respectively, and the medium inlet and the medium outlet are communicated with the second opening; the outer side of the shutter abuts against the inner wall of the main body part at the second opening hole, and the shutter is configured to move along the inner wall when being subjected to a force in the first direction; an elastic part is arranged at one end, far away from the actuating cylinder, of the valve, and the elastic part is used for enabling one end, close to the actuating cylinder, of the valve to abut against a limiting structure of the main body part so as to close the medium inlet; a cylinder cavity of the actuating cylinder is communicated with the first opening, a piston is arranged in the actuating cylinder, and a first sealing structure is arranged between the piston and the inner wall of the actuating cylinder so as to divide a space formed by the cylinder cavity and the first opening which are communicated with each other into two parts which are sealed with each other; the actuator cylinder is provided with an open cavity at one end far away from the main body part, and the main body part is provided with a related cavity at the part forming the first opening; the piston is connected with the valve through a rod-shaped component arranged in the through hole along the first direction, the outer side wall of the part, located between the first opening and the second opening, of the rod-shaped component and the inner side of the main body part are respectively sealed through a first sealing device and a second sealing device which are spaced from each other, wherein the first sealing device is used for sealing control gas, and the second sealing device is used for sealing liquid media; when control gas is introduced into the open cavity, the piston is pushed to drive the rod-shaped part and the valve to move along the inner wall of the second opening hole in the direction away from the actuating cylinder, so that the medium inlet is communicated with the medium outlet, and the valve is limited at the position where the medium inlet is communicated with the medium outlet through medium pressure; when high-pressure control gas is introduced into the closing cavity, the piston is pushed to drive the rod-shaped part and the valve to move towards the direction close to the actuating cylinder along the inner wall of the second opening hole so as to close the medium inlet, and the valve is limited at the position where the medium inlet is closed through the elastic piece.

In one embodiment, the valve structure further comprises a cover plate for sealing connection with the other end of the main body portion away from the actuator cylinder in the first direction, and the elastic member is compressively disposed between the shutter and the cover plate.

In one embodiment, the valve is provided with an inwards concave cavity body near the end of the cover plate, and the cover plate is provided with a discharge port communicated with the cavity body.

In one embodiment, a portion of the body portion between the first opening and the second opening is provided with an annular projection, and the first sealing means and the second sealing means are provided between an outer side of the rod-like member and the annular projection.

In one embodiment, the first sealing device and the second sealing device are both dynamic sealing structures.

In one embodiment, the first sealing means and the second sealing means are both of a wiper ring construction.

In one embodiment, the stopper ring structure comprises a non-metallic jacket on the outside and an energy-accumulating spring on the inside.

In one embodiment, portions of the piston and the shutter facing each other are provided with structures to engage both ends of the rod member, respectively.

Another aspect of the present invention provides a liquid engine including a valve structure as described above.

The utility model discloses a valve structure and liquid engine set up the pressurized strut through main part one side at the valve to set up valve and elastic component at the liquid propellant entrance, can be through letting in control gas in to the pressurized strut, the on-off state of adjustment valve, and when removing control gas, the combined action through elastic component and medium pressure keeps the valve in original position, thereby can be with less control gas quantity, realize the switch to the propellant access & exit, improve liquid engine's working property.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification of the invention, illustrate exemplary embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1-3 are schematic views of the valve structure according to the embodiment of the present invention.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, which should not be considered limiting of the invention, but rather should be understood to be a more detailed description of certain aspects, features and embodiments of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

The dynamic sealing technology has the advantage of zero leakage in practical application, and has better applicability to small-size valves in a low-dielectric pressure environment. However, the large-size metal corrugated pipe is difficult to form, long in production period, large in space structure, low in service life and poor in reliability, so that the purchase cost is increased, and the application of the metal corrugated pipe in the valve is severely restricted.

Generally, the propellant pressure of mainstream liquid rocket engines is generally more than 10 MPa. The control air pressure of the engine usually reaches more than 20MPa, and in order to reduce the control air volume of the engine and the structural size of a valve actuating cavity and realize effective control of the corrugated pipe, the control air pressure needs to be kept in a certain range. Therefore, the engine system needs to add a pressure reduction and stabilization design in the control system, which results in an increase in the number of components of the engine and a decrease in reliability. Through using general stopper circle to move seal structure in valve structure in this application, realized the sealed of wide pressure range, and need not step down and steady voltage system, improved the reliability of engine.

In addition, in order to keep the valve of the active liquid rocket engine in an open or closed state, control air needs to be communicated to the control cavity all the time during the working process of the valve, so that the engine needs to carry a large amount of control air, and the weight and the structural size of the engine are remarkably increased. In addition, the cold and hot temperature difference of the working environment of the engine is large, the vibration intensity in the working process is high, and the reliability of the engine can be seriously influenced by continuously introducing control gas into the valve control cavity.

One aspect of the present invention provides a valve structure for a liquid rocket engine, including a main body unit, an actuating unit, and a holding unit; the main body unit comprises a medium inlet and a medium outlet for liquid to enter and flow out and a medium channel communicated with the medium inlet and the medium outlet, the actuating unit is used for driving the executing unit to move in the medium channel, so that the executing unit enables the medium inlet to be opened or closed, and the retaining unit is used for retaining the executing unit to enable the medium inlet to be kept at a working position. The valve structure of this application through setting up the holding unit, can be in the execution unit back that targets in place, need not to continue to lead to for example control gas, can make the valve be in the work position of opening or closing, has reduced the quantity of control gas, improves the thrust-weight ratio of engine.

Referring to fig. 1, the body unit includes a body portion 1, the body portion 1 having a through-hole in a first direction S1; the actuating unit comprises an actuating cylinder 2, and the actuating cylinder 2 is used for being connected with one end of the main body part 1 in a sealing mode in the first direction S1; the actuating unit includes the shutter 4, and the holding unit includes the elastic member 5, and in first direction S1, the other end of the main body portion 1 is connected with the cover plate 3 in a sealing manner, and the elastic member 5 is disposed between the cover plate 3 and the shutter 4 to provide a holding force for the shutter 4.

The through-hole includes a first opening 11 and a second opening 12 formed respectively inward at both ends of the main body portion 1 in the first direction S1, and the main body portion 1 is provided with a medium inlet 13 and a medium outlet 14 communicating with the second opening 12. The body part 1 is provided with the shutter 4 at an inner side where the second opening hole 12 is formed, an outer side of the shutter 4 abuts on an inner wall of the body part 1 at the second opening hole 12, and the shutter 4 is configured to move along the inner wall when receiving a force in the first direction S1.

As described above, the elastic member 5 is compressively disposed between the shutter 4 and the cover plate 3, and the elastic member 5 applies a force to the shutter 4 toward the actuating cylinder 2, so that one end of the shutter 4 away from the cover plate 3 abuts against the stopper structure 15 of the body 1, thereby the shutter 4 closes the medium inlet 11.

The cylinder cavity of the actuating cylinder 2 is communicated with the first opening hole 11, a piston 6 is arranged in the actuating cylinder 2, and a first sealing structure 7 is arranged between the piston 6 and the inner wall of the actuating cylinder 2 so as to divide the space formed by the cylinder cavity and the first opening hole 11 into two parts which are sealed with each other. The ram 2 is provided with an open cavity 21 at an end remote from the body 1, and the body 1 is provided with a cavity 16 at the portion where the first opening 11 is formed.

The piston 6 and the shutter 4 are connected by a rod member 8 disposed in the through hole along the first direction S1, the rod member 8 is sealed by a first sealing means 9 and a second sealing means 10 spaced from each other between the outside of the portion between the first chamber 11 and the second chamber 12 and the inside of the main body 1, respectively, so that the first sealing means 9 is used for sealing the high-pressure control gas entering from the open chamber 21 and the closed chamber 16, and the second sealing means 10 is used for sealing the liquid medium from the second opening 12.

When high-pressure control gas is introduced into the open cavity 21, the piston 6 is pushed to drive the rod-shaped part 8 and the valve 4 to move towards the direction close to the cover plate 3 along the inner wall of the second opening 12, so that the medium inlet 13 is communicated with the medium outlet 14, and the valve 4 is limited at a position where the medium inlet 13 is communicated with the medium outlet 14 through medium pressure.

When high-pressure control gas is introduced into the closing cavity 16, the piston 6 is pushed to drive the rod-shaped part 8 and the shutter 4 to move along the inner wall of the second opening 12 in the direction away from the cover plate 3 so as to close the medium inlet 13, and the shutter 4 is limited to a position where the medium inlet 13 and the medium outlet 14 are closed through the elastic member 5.

The utility model discloses valve structure lets in control gas through opening the chamber and closing the chamber at pressurized strut, main part, can promote the piston in the pressurized strut and drive shaft-like part and valve motion, realizes the switch to the medium entry to keep the valve at the work position through elastic component and medium pressure, under the prerequisite that reduces the quantity of control gas, improve the valve performance.

It should be noted that when the valve is in the closed state, the shutter 4 can be kept sealed by the medium pressure flowing from the medium inlet 13 and the elastic member 5, i.e. it is not necessary to continuously open the control gas from the closed chamber 16. Similarly, when the valve is opened, a low-pressure cavity is formed between the valve 4 and the discharge port (when the cover plate 3 is provided with the discharge port), and pressure difference is formed between the low-pressure cavity and the high-pressure medium at the inlet, and the medium pressure difference overcomes the elasticity of the elastic part to enable the valve to be in the opened state. For example, it is also possible to simultaneously introduce control gas into the open chamber 21 of the actuator cylinder 2 to cooperate with the pressure difference of the medium to jointly place the flap 4 in the open position, and this variant on the basis of the present application is also within the scope of the present application.

Referring to fig. 2, for example, in one embodiment, the portion of the body portion 1 between the first opening 11 and the second opening 12 is provided with an annular projection 17, and the first sealing means 9 and the second sealing means 10 are arranged spaced apart from each other between the outside of the rod-like member 8 and the annular projection 17. The utility model discloses valve structure is protruding through setting up the annular at two cavity spares to set up sealing device between the annular is protruding and shaft-like part outside, can effectively reduce sealing device's radial dimension, improve sealed effect.

In this embodiment, for example, the first sealing device 9 and the second sealing device 10 are both dynamic sealing structures. For example, the first sealing means 9 and the second sealing means 10 are both of a corkring construction.

For example, the stopper ring structure comprises a non-metallic jacket on the outside and an energy-accumulating spring on the inside. For example, the non-metallic sealing jacket may be precision machined from tetrafluoroethylene, filled polytetrafluoroethylene, or other high performance polymeric material. For example, the energy storage spring may be made of corrosion resistant metal. The material selection of the non-metal jacket and the energy storage spring can ensure that the universal stopper ring has stable performance within the temperature range of minus 268 ℃ to 427 ℃, and can not react with most liquid media when being used for a low-temperature sealing valve of a liquid rocket engine.

It should be added that the flooding plug sealing ring has the following advantages:

(1) the dynamic sealing structure of the valve product for the low-temperature high-pressure liquid rocket engine adopting the universal plug ring dynamic sealing mode is simple and reliable, has short production period and low cost, and meets the requirements of high-pressure low-temperature dynamic sealing.

(2) Compared with the high-pressure valve for the existing liquid rocket engine, the dynamic sealing structure of the flooding plug ring has high adaptability in the low-temperature liquid rocket engine, the size of the dynamic sealing structure is more compact than that of a metal corrugated pipe, and the structural size is small, so that the structural size and weight of the valve body are reduced, and the thrust-weight ratio of the liquid rocket engine is improved.

(3) The universal plug ring has a medium pressure self-tightening effect, and can improve the control air pressure of the valve, reduce the action area of the piston, further reduce the structural size of a valve actuating mechanism, reduce the volume of an engine with an air bottle, reduce the air consumption of the engine, and improve the reliability, thrust-weight ratio and other performance parameters of the low-temperature liquid rocket engine within the allowable pressure range under the condition of the same operating force.

For example, the jamming collar may be disposed in a sealing groove, i.e. a matching annular groove on the outer surface of the annular projection 17 of the body portion 1, outside the rod-like member 8, and disposed in the annular groove, so that the inner side of the jamming collar enters the annular groove outside the rod-like member 8 and the outer diameter portion enters the annular groove in the surface of the annular projection 17. When the plunger ring is arranged in the sealing groove, the spring in the plunger ring is supported outwards by the pressure, forcing the jacket lip against the sealing groove, whereby a reliable, tight sealing is formed between the annular projection 17 and the rod-shaped part 8.

In addition, the spring can provide permanent elasticity for the sealing jacket, can effectively make up for the wearing and tearing of sealing material and the skew and the off-centre of cooperation part, provides redundant initial sealing force for general stopper circle. When liquid medium enters the inner cavity of the universal plug ring, the nonmetal jacket can be supported, the self-tightening sealing effect is achieved, and higher sealing force is achieved. That is, the higher the pressure of the liquid medium is within the allowable pressure range, the better the sealing effect is.

In one embodiment, the elastic member 5 is a spring, a compression spring, or a leaf spring. And an elastic member 5 is compressively disposed between the cover plate 3 and the shutter 4 to apply an elastic force to the shutter 4 toward the cylinder 2 side. Further, the magnitude of the elastic force applied to the shutter 4 by the elastic member 5 may be determined according to the pressure difference between the high-pressure liquid at the liquid medium inlet 13 and the drain port 31 (in the case where the drain port is provided in the cover plate). That is, when the shutter 4 is in the position where the medium inlet 13 is opened, the above-mentioned pressure difference can resist the resilient force of the elastic member in the compressed state, so that the liquid medium can flow in from the medium inlet 13 and flow out from the medium outlet 14 even when the ventilation of the open chamber 21 is stopped. For example, the above-mentioned open position may be a position where the medium inlet 13 is fully opened.

The utility model discloses valve structure keeps the export sealed by entry medium pressure and spring force (under the circumstances that the elastic component is the spring) when closing, and overcomes the spring force by the pressure differential of medium entry and discharge opening when opening and keeps the export open. Specifically, when the valve is switched from a closed state to an open state, control gas needs to be introduced, the control gas is disconnected after the valve acts in place, and the high-pressure medium pressure overcomes the resilience force of the spring to enable the medium outlet to be in the open state. When the valve structure needs to be switched from an opening state to a closing state, control gas needs to be introduced into the valve control cavity to close the valve control cavity, the control gas is disconnected after the valve is closed in place, and the valve is kept sealed by medium pressure and spring force. The control gas is only introduced when the valve acts, and the control gas is cut off after the valve acts in place, so that the control gas quantity of the engine is saved, and the reliability of the engine is improved.

Referring to fig. 3, in one embodiment, the shutter 4 has a cavity 41 at an end thereof adjacent to the cover plate 3, and the cover plate 3 has a discharge port 31 communicating with the cavity 41. For example, the cavity 41 may be a cylindrical cavity (the cavity facing the cover plate 3 shown in fig. 3) having an opening at one end, and the substantially cylindrical elastic member 5 (a cylindrical spring shown in fig. 3) may abut on a side wall of the cylindrical cavity and be in a compressed state to apply a force to the shutter 4 in a direction toward the ram 2.

In one embodiment, portions of the piston 6 and the shutter 4 facing each other are provided with structures to engage both ends of the rod member 8, respectively. For example, as shown, the rod-like member 8 may be a shaft structure having a portion of progressively decreasing diameter at the end that mates with the piston 6, and the mating end of the piston 6 is provided with a groove that mates with the end of the shaft structure. Correspondingly, the mating end of the shutter 4 has a cylindrical slot, and the other end of the shaft structure is inserted into the cylindrical slot of the shutter 4 to match therewith. For example, the cylindrical slot of the piston 6 and the slot of the shutter 4 may both have an interference fit with the corresponding ends of the shaft, thereby ensuring that the shaft structure does not deflect in the radial direction, improving the reliability of the valve operation.

In one embodiment, the stop structure 15 is an annular projection provided on the inside of the body 1, which limits the movement of the shutter 4 towards the ram 2 by abutting against the edge of the shutter 4. The extreme position of the movement of the shutter 4 towards the actuator cylinder 2 is the position in which its edge abuts the annular projection and when the shutter 4 abuts the annular projection its side walls may just completely close the media inlet 13.

The above embodiments can be combined with each other and have better technical effects.

Another aspect of the present invention provides a liquid engine, including a valve structure as described above. The utility model discloses a liquid engine has adopted the valve structure in above-mentioned each embodiment, consequently has corresponding technological effect.

The utility model discloses a valve structure and liquid engine set up the pressurized strut through main part one side at the valve to set up valve and elastic component at the liquid propellant entrance, can be through letting in control gas in to the pressurized strut, the on-off state of adjustment valve, and when removing control gas, keep the valve in original position through elastic component and medium, can realize the switch to the propellant access & exit with less control gas quantity, improve liquid engine's working property.

Compare with current high pressure valve for liquid rocket engine, the utility model discloses a valve structure of embodiment uses general stopper circle seal structure to have fine adaptability at the liquid rocket engine, and the size of moving seal structure is compacter than corrugated metal pipe moving seal structure, has reduced the structural dimension and the weight of valve body.

In addition, the universal piston ring has a medium pressure self-tightening effect, and can improve the control force of the valve, reduce the action area of the piston and the size of an actuating structure of the valve in the pressure allowable range under the condition of the same operation force, so that the volume of the engine with the gas cylinder is reduced, and the carrying force of the rocket is improved.

In addition, the valve has a self-holding function after the valve acts in place, namely after the control gas is introduced and the valve acts in place, the gas is not required to be continuously introduced for maintenance, the gas consumption for controlling the engine is reduced, the reliability of the engine is improved, and therefore the reliability, the thrust-weight ratio and other performance parameters of the low-temperature liquid rocket engine are further improved.

The foregoing is only an illustrative embodiment of the present invention, and any equivalent changes and modifications made by those skilled in the art without departing from the spirit and principles of the present invention should fall within the protection scope of the present invention.

Claims

1. A valve structure is applied to a liquid rocket engine and is characterized by comprising a main body unit, an actuating unit, an executing unit and a holding unit;

the main body unit comprises a medium inlet and a medium outlet for liquid to enter and flow out and a medium channel communicated with the medium inlet and the medium outlet, the actuating unit is used for driving the executing unit to move in the medium channel, so that the executing unit enables the medium inlet to be opened or closed, and the retaining unit is used for retaining the executing unit to enable the medium inlet to be kept at a working position.

2. The valve structure according to claim 1, wherein the body unit includes a body portion having a through hole extending in a first direction, the actuating unit includes a cylinder for sealing connection with one end of the body portion in the first direction, the actuating unit includes a shutter disposed inside a second opening of the body portion, and the holding unit includes an elastic member compressively disposed on a side of the shutter away from the actuating side;

the through hole includes a first opening and a second opening formed inward at both ends of the main body in the first direction, respectively, and the medium inlet and the medium outlet are communicated with the second opening; the outer side of the shutter abuts against the inner wall of the main body part at the second opening hole, and the shutter is configured to move along the inner wall when being subjected to a force in the first direction; the elastic part is arranged at one end, far away from the actuating cylinder, of the valve, and the elastic part is used for enabling one end, close to the actuating cylinder, of the valve to abut against the limiting structure of the main body part so as to close the medium inlet;

a cylinder cavity of the actuating cylinder is communicated with the first opening, a piston is arranged in the actuating cylinder, and a first sealing structure is arranged between the piston and the inner wall of the actuating cylinder so as to divide a space formed by the cylinder cavity and the first opening which are communicated with each other into two parts which are sealed with each other; the actuator cylinder is provided with an open cavity at one end far away from the main body part, and the main body part is provided with a related cavity at the part forming the first opening;

the piston is connected with the valve through a rod-shaped component arranged in the through hole along the first direction, the outer side wall of the part, located between the first opening and the second opening, of the rod-shaped component and the inner side of the main body part are respectively sealed through a first sealing device and a second sealing device which are spaced from each other, wherein the first sealing device is used for sealing control gas, and the second sealing device is used for sealing liquid media;

when control gas is introduced into the open cavity, the piston is pushed to drive the rod-shaped part and the valve to move along the inner wall of the second opening hole in the direction away from the actuating cylinder, so that the medium inlet is communicated with the medium outlet, and the valve is limited at the position where the medium inlet is communicated with the medium outlet through medium pressure;

when high-pressure control gas is introduced into the closing cavity, the piston is pushed to drive the rod-shaped part and the valve to move towards the direction close to the actuating cylinder along the inner wall of the second opening hole so as to close the medium inlet, and the valve is limited at the position where the medium inlet is closed through the elastic piece.

3. The valve structure of claim 2, further comprising a cover plate for sealing engagement with the body portion at the other end thereof remote from the actuator cylinder in the first direction, the resilient member being compressively disposed between the shutter and the cover plate.

4. The valve structure according to claim 3, wherein the shutter has an inwardly recessed cavity near the end of the cover plate, and the cover plate has a discharge opening communicating with the cavity.

5. The valve structure according to claim 2, wherein a portion of the main body portion between the first opening and the second opening is provided with an annular projection, and the first sealing means and the second sealing means are provided between an outer side of the rod-like member and the annular projection.

6. The valve structure of claim 2, wherein the first and second sealing means are both dynamic sealing structures.

7. The valve structure of claim 6, wherein the first sealing means and the second sealing means are of a wiper ring structure.

8. The valve structure of claim 7, wherein said stopper ring structure comprises a non-metallic jacket on the outside and an energy-storing spring on the inside.

9. The valve structure according to claim 2, wherein portions of said piston and said shutter facing each other are provided with structures for engaging both ends of said rod member, respectively.

10. A fluid engine comprising a valve arrangement according to any one of claims 1 to 9.