Flat valve disc sealing structure, gas injection valve and soft sealing element size design method

Abstract

Provided are a flat valve disc sealing structure, a flat valve disc comprising an upper valve disc and a lower valve disc made of metal, the upper valve disc being provided with an upper through hole, the lower valve disc being provided with a lower through hole, the upper through hole and the lower through hole being staggered, the sealing structure comprising: a soft sealing element arranged on the surface of the lower valve disc and facing the upper through hole, the surface area of the soft sealing element being greater than the hole section of the upper through hole, so that at least part of the soft sealing element is extruded by the upper valve disc; and the soft sealing element is arranged to protrude from the surface of the lower valve disc when not under stress, forming a protruding height, the protruding height being arranged to be consistent with the surface of the lower valve disc after the soft sealing element is extruded by the upper valve disc. The sealing structure can provide better sealing effect while reducing the requirements of flat metal processing technology. Also provided are a gas injection valve and a method for designing the size of a soft sealing element.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas injection valves, in particular to the sealing of the valve. BACKGROUND

[0002] In the existing large-area flat valve disc sealing structure in the form of metal-to-metal contact, in order to ensure the sealing performance, the surface of the valve disc usually needs to be processed with high precision, including precision treatment of flatness and surface roughness. In particular, for large-area valve discs with a surface area greater than 10 cm, the yield of machined parts meeting the precision is low, and the sealing is achieved by butt joint of two valve discs, which further increases the processing difficulty.

[0003] For gas injection valves, since the working medium is gas, the sealing requirement for the valve disc is higher than that for liquid, that is, even a small defect or shape deformation on the surface of the valve disc will significantly increase the leakage of gas. The valve disc surface also has dirty particles and deposits that may be brought in by the gas or tempering, which can damage the sealing surface and reduce the sealing performance.

[0004] It is necessary to provide a sealing structure that can reduce the requirement for flatness machining precision while ensuring high sealing performance. SUMMARY

[0005] An object of the present application is to provide a flat valve disc sealing structure that can reduce the requirement for flatness machining process while providing better sealing effect.

[0006] To achieve the above-mentioned object, the flat valve disc sealing structure is used for sealing a flat valve disc, the flat valve disc includes an upper valve disc and a lower valve disc made of metal, the upper valve disc is provided with an upper through hole, the lower valve disc is provided with a lower through hole, the upper through hole and the lower through hole are arranged alternately, and the sealing structure includes: a soft sealing element arranged on the surface of the lower valve disc and facing the upper through hole, the surface area of the soft sealing element is greater than the hole section of the upper through hole, so that at least part of the soft sealing element is extruded by the upper valve disc; and the soft sealing element is arranged to protrude from the surface of the lower valve disc when not under stress, forming a protrusion height, the protrusion height is arranged to be consistent with the surface of the lower valve disc after the soft sealing element is extruded by the upper valve disc.

[0007] In one or more embodiments, the soft sealing element is made of flexible material.

[0008] In one or more embodiments, the lower valve disc is provided with a groove for accommodating at least part of the soft sealing element.

[0009] In one or more embodiments, the soft sealing element forms a soft sealing ring belt.

[0010] In one or more embodiments, the soft seal is dispersedly arranged on the lower valve disc.

[0011] In one or more embodiments, the convex height ranges from 0.08 to 0.12 mm.

[0012] Another object of the present application is to provide a gas injection valve, comprising: an upper valve disc and a lower valve disc facing each other, the upper valve disc being provided with an upper through hole, the lower valve disc being provided with a lower through hole, the upper through hole and the lower through hole being staggered; an electromagnetic component for driving the upper valve disc to reciprocate, comprising a magnet, a coil, an armature and a return spring, the armature being connected with the lower valve disc; an air inlet and an air outlet; and the above-mentioned flat valve disc sealing structure.

[0013] In one or more embodiments, the injection valve further comprises a diaphragm ring and a valve body shell, the valve body shell being sleeved outside the electromagnetic component, the upper valve disc and the lower valve disc, one end of the diaphragm ring being connected with the armature, and the other end being connected with the valve body shell to form a sealing surface.

[0014] In one or more embodiments, the air inlet is arranged on the valve body shell, and the air outlet is arranged on the lower valve disc.

[0015] Still another object of the present application is to provide a soft seal size design method for determining the size of a soft seal, the method comprising the following steps: determining the spring pre-tightening force of a return spring under a closed working condition, and determining the gravity of a component applied on the soft seal; determining the value range of a strain, and determining the contact area range of the soft seal with the upper valve disc according to and the value range, wherein F s is the spring pre-tightening force, G is the gravity of the component applied on the soft seal, A is the contact area of the soft seal with the upper valve disc, ε is the strain, and E is the elastic modulus of the soft seal; determining the convex height of the soft seal according to and determining the overall height of the soft seal, wherein H0 is the convex height, and H s is the overall height of the soft seal.

[0016] The flat valve disc sealing structure inserts the soft sealing member between the upper valve disc and the lower valve disc, forms the soft and hard sealing combined sealing form by the strong deformation ability of the soft sealing member and the metal sealing surface, and when the valve is closed, the soft sealing member is compressed to the height consistent with the metal sealing surface, and under the action of the pressure difference and the pre-tightening force, the soft sealing member forms the double sealing with the other metal valve disc sealing surface. The soft sealing material can adapt to the slight deformation of the valve disc surface and fill the gap, thereby effectively improving the sealing performance, reducing the machining precision requirement of the metal valve disc, especially the large size valve disc, and by means of the characteristics that the hard sealing can bear the large stress caused by the large pressure difference and the impact frequency, the stability of the valve disc sealing is maintained, the performance of the soft sealing material is protected, and the sealing performance of the gas injection valve is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other features, properties and advantages of the present application will become more apparent by the following description of the application, when taken in conjunction with the accompanying drawings and examples, in which:

[0018] Figure 1 is a sectional view of an embodiment of the gas injection valve;

[0019] Figure 2 is a schematic view of the flat valve disc sealing structure;

[0020] Figures 3-4 is an enlarged view of the soft sealing member.

[0021] SYMBOL EXPLANATION

[0022] 1 electromagnet

[0023] 2 compression washer

[0024] 3 return spring

[0025] 4 diaphragm ring

[0026] 5 valve body shell

[0027] 6 sealing ring

[0028] 7 electromagnetic coil

[0029] 8 armature

[0030] 10 upper valve disc

[0031] 11 soft sealing member

[0032] 12 lower valve disc DETAILED DESCRIPTION

[0033] The application will be further described below in connection with specific embodiments and drawings, and more details are set forth in the following description in order to fully understand the application, but the application can be implemented in many other ways different from the description, and those skilled in the art can make similar generalizations and deductions according to the actual application without departing from the concept of the application, so the protection scope of the application should not be limited by the specific embodiments.

[0034] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used as a limitation on the actual claimed protection scope of the application.

[0035] The gas injection valve is a device used in the fuel injection system of an internal combustion engine, commonly used in natural gas engines, and its main function is to accurately inject gas into the combustion chamber to ensure that the mixing ratio of fuel and air is appropriate, thereby achieving efficient combustion and reducing emissions.

[0036] As shown in Figure 1 The gas injection valve includes an electromagnet 1, a compression washer 2, a return spring 3, a diaphragm ring 4, a valve body shell 5, a sealing ring 6, an electromagnetic coil 7, an armature 8, an upper valve disc 10, and a lower valve disc 12. The valve body shell 5 is sleeved outside the electromagnet 1, the compression washer 2, the return spring 3, the diaphragm ring 4, the sealing ring 6, the electromagnetic coil 7, the armature 8, the upper valve disc 10, and the lower valve disc 12, and the inner wall surface of the valve body shell 5 has a corresponding stepped structure to limit the positions of the components.

[0037] The gas injection valve also includes an air inlet A and an air outlet B. The air inlet A is specifically arranged between the upper valve disc 10 and the armature 8, and the air outlet B is arranged on the lower valve disc 12.

[0038] The electromagnet 1 is made of a strong magnetic material, such as a stack of silicon steel sheets, and the electromagnetic coil 7 is wound around the electromagnet 1, which is the input port for external excitation current. A blind hole is provided in the middle of the electromagnet 1 to limit the position of the return spring 3.

[0039] The armature 8 is a moving part, and the center of the upper part of the armature 8 has a lower fixed port of the return spring 3, so it is necessary to ensure that the axis position of the return spring coincides with the center position of the hole to ensure the spring movement path. The center of the armature 8 is in the form of a through hole, and an external thread is formed on the outside to connect the movement. The outer edge of the armature 8 has a groove formed around it to fix the inner edge of the diaphragm ring 4, and the groove maintains a seal with the diaphragm ring 4.

[0040] The diaphragm ring 4 is made of flexible material and has good elastic deformation ability. The inner edge of the diaphragm ring 4 is placed in the groove of the armature 8, and the outer edge is placed in the groove of the inner cavity surface of the valve body shell 5, thereby forming two sealing surfaces, which effectively isolate the gas located above and below the diaphragm ring 4.

[0041] The lower surface of the upper valve disc 10 is provided with an upper through hole 100, which is preferably a ring belt hole, so as to ensure a larger air flow in a small lifting distance.

[0042] The upper surface of the lower valve disc 12 is provided with a lower through hole 120, which is preferably also a ring belt hole. The upper through hole 100 and the lower through hole 120 are staggered.

[0043] The basic working principle of the gas injection valve is that when the electromagnetic coil is powered on, the electromagnet 1 is subjected to an upward electromagnetic force, which drives the upper valve disc 10 to be lifted upward, and is limited by the step surface of the inner wall of the valve body shell to the maximum lifting distance. At this time, the gas flow from the air inlet A passes through the ring belt gap G of the upper valve disc 10 and the fixed lower valve disc 12 to provide the required gas flow to the downstream. When the power is off, the electromagnet 1 and the upper valve disc 10 are subjected to downward action force of the self weight and the reset spring 3, so as to quickly fall back, so that the lower surface of the upper valve disc 10 and the upper surface of the lower valve disc 12 are re-closely attached together, and due to the staggered and non-overlapping gas holes between the ring belts, the air inlet channel is isolated, so that the valve is in the cut-off mode of stopping injection.

[0044] Figure 2 The valve has a flat valve disc structure, which must have a corresponding sealing structure. Since the working medium is gas such as fuel gas, the sealing performance is required to be high, and even close to "zero leakage" is required. Since the upper and lower valve discs are in metal-to-metal contact (MMC), the requirements for the flatness, smoothness and wear resistance of the metal surface are significantly increased, which increases the processing cost.

[0045] The valve disc sealing structure described in the present application solves the above problems, can reduce the flatness processing precision requirement, avoid the risk of damage to the surface of the valve disc by dirty particles and reduce the sealing performance or failure, and ensure high sealing performance.

[0046] The sealing structure for sealing the flat valve disc is shown in Figures 2-4 , Figure 2 The structure of the flat valve disc is shown, which includes an upper valve disc 10 and a lower valve disc 12 made of metal. The upper valve disc 10 is provided with an upper through hole 100, and the lower valve disc 12 is provided with a lower through hole 120. The upper through hole 100 and the lower through hole 120 are staggered. Figure 3 When the valve disc is in an open state, the upper valve disc 10 and the lower valve disc 12 are separated to form a gap G as shown, and the gas input from the inlet A flows into the gap G through the upper through hole 100, and then flows into the lower through hole 120, and then flows out through the outlet B.

[0047] The sealing structure comprises a soft sealing member 11 arranged on the surface of the lower valve disc 12 and opposite to the upper through hole 100. The surface area of the soft sealing member 11 is larger than the hole section of the upper through hole 100, so that at least part of the soft sealing member 11 is extruded by the upper valve disc 10.

[0048] Further, the soft sealing member 11 is arranged to protrude from the surface of the lower valve disc 12 when not under stress, forming a protruding height H0, which is arranged to be compressed to be flush with the surface of the lower valve disc 12 after the soft sealing member is extruded by the upper valve disc 10, as shown in Figure 4 wherein b0 is the length of the contact area of the soft sealing member with the upper valve disc 10, b s is the total length of the soft sealing member, and b up is the length of the area not in contact with the upper valve disc.

[0049] Specifically, the lower valve disc 12 is provided with a groove for accommodating at least part of the soft sealing member 11, so as to load the soft sealing member.

[0050] The principle of the sealing is as follows: when the valve is closed, since the surface of the soft sealing member 11 is slightly higher than the surface of the metal lower valve disc 12 in the free state, the upper valve disc 10 will first contact the soft sealing member 11 when seated, and under the spring pre-tightening force, self-weight and pressure difference, the upper valve disc 10 will exert a downward force on the soft sealing member 11 to make the soft sealing member 11 begin to deform. When the valve is closed, the soft sealing member 11 is compressed to be flush with the surface of the metal lower valve disc 12, that is, at this time, part of the metal surface of the upper valve disc 10 is in contact with the soft sealing member 11, and the other part is in contact with the metal surface of the lower valve disc.

[0051] After being compressed, the soft sealing plane no longer deforms, and since the elastic modulus of the metal is much larger than that of the provided soft sealing material, the metal part bears the remaining valve closing stress. At this time, since the soft sealing can well fit the microscopic defects of the metal surface, it does not need to rely on the machining precision of the metal surface, so it makes up for the defects of the flatness and smoothness error caused by the machining process when the hard sealing surface directly contacts, greatly improving the sealing performance. Moreover, it can further reduce the requirement for the cleanliness of the gas inlet while ensuring the sealing performance. The hard sealing can bear the large stress caused by the large pressure difference and impact frequency, maintain the stability of the valve disc sealing, and protect the performance of the soft sealing material, thereby improving the service life of the elastic soft sealing material.

[0052] Moreover, the convex height H0 needs to meet a certain height. If the convex height H0 is too high, the surface of the soft seal cannot be consistent with the surface of the lower valve plate when compressed by the upper valve plate 10, and a certain height is still generated, so that the upper valve plate cannot be well attached to the lower valve plate, and the soft seal can also generate a vibration rebound, which affects the upper valve plate. In addition, since the gas injection valve is a high-frequency valve, the soft seal cannot be determined after long-term use, and the lift of the upper valve plate is difficult to estimate, which affects the accuracy of the lift and further affects the flow control of the gas injection valve. Finally, the soft seal with too high convexity can also affect the smoothness of the flow path in the gap G.

[0053] In some embodiments, the convex height H0 is set to 0.08-0.12 mm, preferably 0.1 mm. It can be understood that the convex height H0 should be designed as small as possible within the range.

[0054] The selection of the soft seal material needs to consider the working environment of the valve first, and needs to select a suitable material according to, for example, gas conditions and temperature, and also needs to consider compatibility issues such as gas corrosion resistance and temperature resistance. In some embodiments, the soft seal is a flexible material, including but not limited to fluororubber, hydrogenated butadiene-acrylonitrile rubber, perfluoroether, ethylene-propylene-diene rubber, hydrogenated butadiene-acrylonitrile rubber, etc. For example, if the medium is ammonia gas or other gas with special corrosive properties, fluororubber is not suitable for this medium, and other flexible materials compatible with the transported medium and stable need to be replaced, such as ethylene-propylene-diene rubber.

[0055] In some embodiments, the soft seal forms a soft seal ring. The annular area b0 forms a soft seal ring that contacts the upper valve plate 10. In other embodiments, the soft seal can also be distributed dispersedly on the lower valve plate 12.

[0056] Taking the soft seal ring as an example, when designing the structure of the soft seal ring, the appropriate ring width, ring thickness, etc. should be designed according to the structure size of the flat valve plate. It needs to be considered that when there is no pressure difference, the valve should also meet the requirement that the soft seal material is flush with the metal surface when closed. The following introduces the specific steps of a soft seal size design method.

[0057] First, according to the spring compression amount and the spring stiffness, the pre-tightening force F of the spring under the closed working condition of the valve plate is calculated s ; at the same time, the weight of all moving parts such as the upper valve plate, the armature, the connecting bolt, etc. is obtained as the gravity G applied to the soft seal.

[0058] The elastic modulus E of the soft seal is determined.

[0059] In order to fully exert the sealing ability of the soft seal material, and considering the recovery ability of the soft seal material due to the frequent opening of the valve plate, the compression strain ε of the soft seal is generally set to be within the range of 0.05-0.1.

[0060] The contact area can be pre-designed to determine the contact area A between the soft sealing ring and the upper valve disc. Taking the soft sealing ring as an example, the contact width between the soft sealing ring and the upper valve disc is b0. If the diameter of the inner ring of the valve disc in contact with the ring is d... u,i (i is the first inner ring, and there are n rings in total), then the area of ​​all contact rings is Based on the total sealing ring area A and elastic modulus E of the soft seal in contact with the upper valve disc, the strain generated by the soft seal material under stress can be estimated, i.e.

[0061]

[0062] Will The calculation results are compared with 0.05 to 0.1 to ensure that the design of the total area of ​​the sealing ring meets the requirements.

[0063] Alternatively, the range of values ​​for the compressible strain ε can be directly substituted into the equation. The appropriate contact area A and contact width b0 of the soft sealing ring are calculated using a range of 0.05-0.1.

[0064] The overall height Hs of the soft seal can also be calculated based on the strain. After determining the protrusion height H0 of the lower valve disc in its natural state, the overall thickness H of the soft seal is then determined. s for Once the overall thickness of the soft seal is calculated, it can guide the creation of the groove on the lower valve disc 12.

[0065] Of course, when the valve is working, it is subjected to the force F of the pressure difference between the upstream and downstream sides. p When the valve closes, the resultant force will increase to F. s +G+F p However, at this point, due to the restriction of the hard sealing metal surface, the soft sealing material will not be further compressed, and the remaining stress is borne by the metal sealing surface, thereby ensuring that the strain of the valve's soft sealing material is controllable and the valve is stable.

[0066] In combination with the introduction of the above-mentioned flat valve disc sealing structure, it can also be understood that a gas injection valve comprising the above-mentioned sealing structure, by designing a soft sealing element located between the upper valve disc and the lower valve disc, with the help of its strong deformation ability, cooperating with the metal sealing surface to form a soft and hard sealing combined sealing form, when the valve is closed, the soft sealing will be compressed to the same height as the metal sealing surface, under the action of pressure difference and pre-tightening force, and the other metal valve disc sealing surface forms double sealing. The soft sealing material can adapt to the slight deformation of the valve disc surface and fill the gap, thereby effectively improving the sealing performance, reducing the machining precision requirement of the metal valve disc, especially for large size valve disc, at the same time, with the help of the characteristics of hard sealing that can withstand the large stress caused by large pressure difference and impact frequency, the stability of the valve disc sealing is maintained, and the performance of the soft sealing material is protected, and the sealing performance of the gas injection valve is improved.

[0067] It should be noted that the use of the words "first", "second" and the like to describe various components is merely intended to differentiate the components from one another, and does not necessarily imply special significance. Therefore, the above words cannot be understood as limiting the scope of protection of the present application.

[0068] Meanwhile, specific words are used in the present application to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "an embodiment" or "one embodiment" or "an alternative embodiment" mentioned in different positions in the specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be properly combined.

[0069] Although the present application is disclosed with the above-mentioned preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification of the above-mentioned embodiments according to the technical essence of the present application, which does not deviate from the technical solution of the present application, falls within the protection scope defined by the claims of the present application.

Claims

1. A method for designing the size of a soft seal for a flat valve disc sealing structure of a gas injection valve, the flat valve disc sealing structure being used to seal a flat valve disc, the flat valve disc comprising an upper valve disc and a lower valve disc made of metal, the upper valve disc being provided with upper through holes, the lower valve disc being provided with lower through holes, the upper through holes and the lower through holes being staggered, the sealing structure comprising: a soft seal made of flexible material, the soft seal being arranged on the surface of the lower valve disc and facing the upper through holes, the surface area of the soft seal being greater than the hole section of the upper through holes, so that at least part of the soft seal is pressed by the upper valve disc; and the soft seal being arranged to protrude from the surface of the lower valve disc when not under force, forming a protruding height, the protruding height being arranged to be consistent with the surface of the lower valve disc after the soft seal is pressed by the upper valve disc, a part of the metal surface of the upper valve disc being in contact with the soft seal, and another part being in contact with the metal surface of the lower valve disc to form a hard seal. The method comprises the following steps: determining the spring pre-tightening force of a return spring under a closed working condition, determining the gravity of components applied on the soft seal, and determining the elastic modulus of the soft seal. The lower valve disc is provided with a groove for accommodating at least part of the soft seal. The soft seal forms a soft seal ring belt. determining a range of values of a strain variable, based on and determining a range of contact areas of the soft seal with the upper valve disc, based on is the spring pre-tightening force, G is the weight force of a component exerted on the soft seal, A is the contact area of the soft seal with the upper valve disc, is the strain variable, E is the elastic modulus of the soft seal; determining the overhang height of the soft seal, according to determining the overall height of the soft seal, wherein Ho is the overhang height, H s is the overall height of the soft seal.

2. The method of claim 1, wherein, The soft seal is arranged on the lower valve disc in a dispersed manner.

3. The method of claim 1, wherein, The range of the protruding height is 0.08-0.12 mm.

4. The method of claim 1, wherein, The method comprises the following steps:

5. The method of claim 1, wherein, the upper valve disc and the lower valve disc facing each other, the upper valve disc being provided with upper through holes, the lower valve disc being provided with lower through holes, the upper through holes and the lower through holes being staggered; 6. Gas injection valve, characterized in that an electromagnetic component for driving the upper valve disc to reciprocate, comprising a magnet, a coil, an armature and a return spring, the armature being connected to the lower valve disc; an air inlet and an air outlet; and a flat valve disc sealing structure obtained by using the design method of any one of claims 1-5. The injection valve further comprises a diaphragm ring and a valve body shell, the valve body shell being sleeved on the outside of the electromagnetic component, the upper valve disc and the lower valve disc, one end of the diaphragm ring being connected to the armature, and the other end being connected to the valve body shell to form a sealing surface. The air inlet is arranged on the valve body shell, and the air outlet is arranged on the lower valve disc. ​ 7. A gas injection valve as claimed in claim 6, characterised in that ​ 8. A gas injection valve as claimed in claim 7, characterised in that ​

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