Air valve device of aero-engine

Abstract

The air valve device of the aero-engine comprises an air inlet valve and an air outlet valve, and each of the air inlet valve and the air outlet valve comprises a rod part and a head part welded to the rod part; wherein a transition circular arc is arranged between the back conical surface and the sealing conical surface of the head part. Through the arrangement of the transition arc, the weight of the valve can be reduced, the transition arc can make the transition between the back conical surface and the sealing conical surface of the valve smooth, and therefore the gas flow resistance during initial opening of the valve can be reduced, the gas inlet efficiency and the gas exhaust efficiency of the valve are guaranteed, and the combustion efficiency can be improved; therefore, the working efficiency of the engine is improved.

Description

Technical Field

[0001] The invention relates to a valve device of an aircraft engine, in particular to a valve device of an aircraft engine with high power density and high strengthening degree. Background Art

[0002] Aircraft engines are highly complex and sophisticated thermal machines. The first to be used were piston engines, whose working principle is that the piston bears the gas pressure, moves repeatedly in the cylinder, and converts this movement into the rotation of the crankshaft through the connecting rod. Among them, the valve, as one of the key components of aircraft engines, is responsible for inputting air into the engine and discharging the exhaust gas after combustion. The valve is divided into intake valve and exhaust valve. The function of the intake valve is to draw air into the engine and mix it with fuel for combustion; the function of the exhaust valve is to discharge the exhaust gas after combustion and dissipate heat.

[0003] Most of the existing valves currently use an integral structure and are made of the same material. However, due to the large differences in the working environment of each valve position, in the actual working process, due to the increase in power density, the heat load increases, the lack of good lubrication conditions, the high impact frequency and high load between the valve and the valve seat, etc., it is easy to cause the sealing cone surface to deform, burn, pitting, and cause premature wear of the seat surface, poor sealing, resulting in reduced engine charging efficiency, power reduction, poor reliability, and overhaul cycle that does not meet the design indicators, and even serious deformation and damage of the valve cone surface, resulting in engine mechanical failure.

[0004] Therefore, Chinese patent document CN206016889U discloses an exhaust valve structure of an engine, comprising: a valve head; a valve stem, which has a first stem portion and a second stem portion, the first stem portion is a solid structure, the center of the second stem portion has a drilled hole, one end of the second stem portion is connected to the first stem portion, and the other end is connected to the valve head, the drilled hole of the second stem portion is filled with metallic sodium; the first stem portion and the second stem portion are made of different materials.

[0005] In the prior art, the exhaust valve is designed to be made of different materials according to the different use environments of the exhaust valve parts, so as to reduce the material cost and meet the increasingly high use requirements of the exhaust valve in harsh use environments. However, in actual use, the problem of low working efficiency of the aircraft engine still exists. Summary of the invention

[0006] In order to solve the technical problem of low working efficiency of aircraft engines in the prior art, the present invention provides a valve device for an aircraft engine, including an intake valve and an exhaust valve, each of which includes a rod and a head welded to the rod; wherein: a transition arc is provided between the back cone surface of the head and the sealing cone surface.

[0007] Although the exhaust valve in the prior art can meet the use requirements of different working environments by using different materials in different parts, the working efficiency of the aircraft engine will be affected by the valve opening during operation. If the intake and exhaust resistance increases, the valve opening will decrease, the intake volume will be insufficient, the exhaust will be blocked, the combustion efficiency will be reduced, and the power output will naturally be weakened, resulting in reduced working efficiency.

[0008] Therefore, in this scheme, the structure of the intake valve and exhaust valve heads is adjusted, and a transition arc is set between the back cone surface and the sealing cone surface of the head. On the one hand, the setting of the transition arc can reduce the weight of the valve. On the other hand, the transition arc can make the transition between the back cone surface and the sealing cone surface of the valve smooth, thereby reducing the gas flow resistance when the valve is first opened, ensuring the valve's intake efficiency and exhaust efficiency, and improving the combustion efficiency, thereby improving the engine's operating efficiency.

[0009] Preferably, the width of the transition arc is not greater than 4 mm. This solution can reduce the weight of the valve while ensuring the strength of the valve.

[0010] Preferably, the sealing cone surface is processed with an arc, and a certain thickness of alloy is welded on the arc. This solution can ensure that the valve still has good strength at high temperatures.

[0011] Preferably, the cladding thickness of the alloy is not less than 0.8 mm, and the hardness is ≥ 40HRC. This solution further ensures that the valve still has good strength at high temperatures.

[0012] Preferably, the distance from the alloy to the end face of the head is not less than 3.6 mm. This solution can control the width of the cone surface while also ensuring the overall strength of the valve.

[0013] Preferably, a groove is provided in the center of the head, and the transition angle between the inclined surfaces on both sides of the groove and the bottom of the hole is 30°. This solution can reduce the deformation of the valve at high temperature and improve the thermal stability of the valve.

[0014] Preferably, a head is welded on the stem of the intake valve at 1 / 2 of the overall length of the intake valve, and a head is welded on the stem of the exhaust valve at 1 / 2 of the overall length of the exhaust valve. Since the temperature of the working environment of the valve will become higher and higher towards the head, this solution can achieve valve strengthening and reliability improvement while reducing overall costs.

[0015] Preferably, the stem of the intake valve is made of 45Cr9Si3 material, the head of the intake valve is made of 21-4N material, the surfacing alloy is made of StelliteF material, the head of the intake valve is made of 21-4N material, the surfacing alloy is made of StelliteF material, the head is solid solution aging treated with a hardness of ≥28HRC, the stem hardness is 30HRC to 40HRC, the valve stem quenching hardness is ≥52HRC, and the depth is 1mm to 44mm. This solution can achieve the improvement of valve strengthening and reliability while reducing overall costs.

[0016] Preferably, the exhaust valve stem is made of 45Cr9Si3, the exhaust valve head is made of 21-4NWNb, the surfacing alloy is made of StelliteF, the head aging hardness is ≥30HRC, the stem hardness is 30HRC-40HRC, the valve stem quenching hardness is ≥52HRC, and the depth is 1mm-4mm. This solution can achieve valve strengthening and reliability improvement while reducing overall costs.

[0017] Preferably, the intake valve and / or exhaust valve are integrally processed and formed, and the intake valve and / or exhaust valve are integrally soft nitrided, with a hardness of >600HV0.2 and a depth of >0.015mm, and the valve head sealing cone surface and the valve stem end surface are ground after nitriding. This solution can further ensure the valve strengthening degree and improve the reliability.

[0018] The present invention has the following beneficial effects: 1. In the present invention, the deformation of the valve under high temperature and high impact load is reduced by adjusting the structure of the intake valve and the exhaust valve, the sealing is improved, and the gas flow resistance when the valve is first opened is reduced, thereby improving the working efficiency of the engine. The engine performance is made more stable, and the change in structure can play a role in reducing the expansion deformation and thermal stress after thermal expansion.

[0019] 2. In the present invention, the intake valve and the exhaust valve are made of multiple groups of different materials with excellent performance, and are formed by welding and then processing, which can achieve the valve strengthening degree and reliability improvement while reducing the overall cost. And by adjusting the intake valve and exhaust valve materials and using a combination of multiple materials, it can still have good thermal stability and strength at high temperatures, increase the wear resistance and sealing of the intake and exhaust valves, improve the reliability of the engine, increase the overhaul cycle by about 1.5 times, and improve the overall heat resistance by about 300℃. It can work stably at about 900℃, and the reliability is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of an intake valve in an embodiment of a valve device for an aircraft engine of the present invention; Figure 2 for Figure 1A is an enlarged schematic diagram; Figure 3 is a schematic diagram of an exhaust valve; Figure 4 for Figure 3 A magnified schematic diagram of B. DETAILED DESCRIPTION

[0021] The following is further described in detail through specific implementation methods: 1. Definition 45Cr9Si3: A chromium-silicon martensitic valve steel with excellent oxidation resistance and moderate mechanical properties. It is mainly used in the manufacture of components such as internal combustion engine intake valves and light-load engine exhaust valves.

[0022] 21-4N: It is a high-performance austenitic heat-resistant steel, also known as 53Cr21Mn9Ni4N or 5Cr21Mn9Ni4N.

[0023] StelliteF alloy: is a cobalt-based alloy mainly composed of cobalt, chromium, tungsten and molybdenum. Its composition includes 32% cobalt, 12% chromium, 3% tungsten and 1% molybdenum, and the rest is iron, nickel and other trace elements.

[0024] Solid solution: refers to the process in which the equilibrium transformation is inhibited when the solid solution solidifies, resulting in a metastable supersaturated solid solution single-phase structure.

[0025] Soft nitriding: A technique that uses gas, liquid or ion methods to infiltrate nitrogen and carbon into the steel surface, aiming to improve the hardness and performance of the material. The basic principle is to release nitrogen and carbon atoms by decomposing urea or other organic media. These atoms are adsorbed on the surface of the workpiece and dissolved in iron to form nitrides and carbides. As the treatment time increases, the nitrogen and carbon atoms diffuse into the interior of the workpiece to form a hardened layer.

[0026] 21-4NWNb: The full name is 5Cr21Mn9Ni4Nb2WN, also known as heat-resistant steel bar or valve steel.

[0027] HV0.2: refers to Vickers hardness, load is 0.2 kg, surface hardness is generally tested on surface carburized or nitrided parts.

[0028] 2. The reference numerals in the drawings of the specification include: rod 1, head 2, groove 3, welding position 4, alloy 5.

[0029] The embodiment is basically as shown in the attached Figure 1-Figure 4 As shown: a valve device of an aircraft engine, including an intake valve and an exhaust valve. The intake valve and the exhaust valve both include a stem 1 and a head 2, and the structure of the intake valve is the same as that of the exhaust valve.

[0030] like Figure 1 and Figure 2 As shown, the material of the stem 1 of the intake valve is 45Cr9Si3, the material of the head 2 is 21-4N, and the head 2 is welded at the welding position 4 located at 1 / 2 of the overall length of the intake valve on the stem 1. The StelliteF alloy 5 with a thickness D5 not less than 0.8mm is welded on the arc of the valve sealing cone surface, and finally the intake valve is obtained by integral processing. The arc of the sealing cone surface is pre-processed on the sealing cone surface, the radius of the arc R3=6.4mm, the valve cone angle a2 is 60°, and the actual error range is within -15′~0°. After processing, the distance D4 from the surfacing alloy 5 to the end face of the intake valve head 2 is not greater than 3.6mm, and the center of the head 2 is processed with a groove 3 with a diameter D1 of 6mm, a depth L1 of 0.5mm, a chamfer a1 of 30°, and a transition between the inclined surface and the bottom radius R1 of 0.5mm, which can reduce the deformation of the intake valve at high temperature, thereby improving thermal stability.

[0031] Among them, the back cone angle a3 of the head 2 of the intake valve is 20°, the valve sealing cone width D3 is 3mm, a transition arc is provided between the back cone surface and the sealing cone surface, the transition arc radius R2 is 6.25mm, and the width D2 of the transition arc does not exceed 4mm at most, which can reduce the weight while making the transition between the valve cone surface and the back cone surface of the head 2 smooth, and can reduce the gas flow resistance received when the intake valve is first opened.

[0032] During the processing of the intake valve, the head 2 of the intake valve is treated with solid solution aging to a hardness of ≥28HRC, the stem 1 is 30HRC~40HRC, and the quenching hardness of the intake valve stem 1 is ≥52HRC with a depth of 1mm~4mm; the head 2 of the exhaust valve is treated with an aging hardness of ≥30HRC, the stem 1 is 30HRC~40HRC, and the quenching hardness of the valve stem 1 is ≥52HRC with a depth of 1mm~4mm. The entire intake valve is treated with soft nitriding, with a hardness of >600HV0.2 and a depth of >0.015mm. After nitriding, the sealing cone surface of the intake valve head 2 and the end surface of the intake valve stem 1 are ground.

[0033] like Figure 3 and Figure 4As shown, the material of the stem 1 of the exhaust valve is 45Cr9Si3, the material of the head 2 of the exhaust valve is 21-4NWNb, and the head 2 is welded at the welding position 4 located at 1 / 2 of the overall length of the exhaust valve on the stem 1. The arc of the valve sealing cone surface is clad with a thickness D5 not less than 0.8mm, and finally the exhaust valve is obtained by integral processing. The arc of the sealing cone surface is pre-processed on the sealing cone surface, the radius of the arc R3=6mm, the valve cone surface angle a2 is 60°, and the actual error range is within -15′~0°. After processing, the distance D4 from the cladding alloy 5 to the end face of the exhaust valve head 2 is not greater than 3.6mm, and the center of the head 2 is processed with a groove 3 with a diameter D1 of 6mm, a depth L1 of 0.5mm, a chamfer a1 of 30°, and a transition between the inclined surface and the bottom radius R1 of 0.5mm, which can reduce the deformation of the exhaust valve at high temperature, thereby improving thermal stability.

[0034] Among them, the back cone angle a3 of the exhaust valve head 2 is 25°, the sealing cone surface width D3 is 3mm, a transition arc is provided between the back cone surface and the sealing cone surface, the transition arc radius R2 is 6.25mm, and the maximum width D2 of the transition arc does not exceed 4mm, which can reduce the weight while making the transition between the valve cone surface and the back cone surface of the head 2 smooth, and can reduce the gas flow resistance received when the exhaust valve is first opened.

[0035] During the processing of the exhaust valve, the head 2 is aged to a hardness of ≥30HRC, the stem 1 is 30HRC to 40HRC, the exhaust valve stem 1 is quenched to a hardness of ≥52HRC, and the depth is 1mm to 4mm. The exhaust valve is soft nitrided as a whole, with a hardness of >600HV0.2 and a depth of >0.015mm. After nitriding, the sealing cone surface of the exhaust valve head 2 and the end surface of the exhaust valve stem 1 are ground.

[0036] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A valve device for an aircraft engine, comprising an intake valve and an exhaust valve, wherein the intake valve and the exhaust valve each comprise a stem and a head welded to the stem; characterized in that: A transition arc is provided between the back cone surface and the sealing cone surface of the head.

2. The valve device of the aircraft engine according to claim 1, characterized in that: The width of the transition arc is no more than 4 mm.

3. The valve device of an aircraft engine according to claim 1 or 2, characterized in that: The sealing cone surface is processed with an arc, and an alloy of a certain thickness is built-up on the arc.

4. The valve device of the aircraft engine according to claim 3, characterized in that: The surfacing thickness of the alloy is not less than 0.8 mm, and the hardness is ≥ 40 HRC.

5. The valve device of the aircraft engine according to claim 4, characterized in that: The distance from the alloy to the end face of the head is not less than 3.6 mm.

6. The valve device of the aircraft engine according to claim 5, characterized in that: A groove is provided at the center of the head, and the transition angle between the inclined surfaces on both sides of the groove and the bottom of the hole is 30°.

7. The valve device of the aircraft engine according to claim 6, characterized in that: The head is welded on the stem of the intake valve at a position 1 / 2 of the overall length of the intake valve, and the head is welded on the stem of the exhaust valve at a position 1 / 2 of the overall length of the exhaust valve.

8. The valve device of the aircraft engine according to claim 7, characterized in that: The stem of the intake valve is made of 45Cr9Si3 material, the head of the intake valve is made of 21-4N material, the surfacing alloy is made of StelliteF material, the head has a solid solution aging treatment hardness ≥28HRC, the stem hardness is 30HRC~40HRC, the valve stem has a quenching hardness ≥52HRC, and the depth is 1mm~44mm.

9. The valve device of the aircraft engine according to claim 8, characterized in that: The exhaust valve stem is made of 45Cr9Si3, the exhaust valve head is made of 21-4NWNb, the surfacing alloy is made of StelliteF, the head aging hardness is ≥30HRC, the stem hardness is 30HRC~40HRC, the valve stem quenching hardness is ≥52HRC, and the depth is 1mm~4mm.

10. The valve device of the aircraft engine according to claim 9, characterized in that: The intake valve and / or the exhaust valve are integrally processed and formed, and the intake valve and / or the exhaust valve are integrally soft nitrided, with a hardness of >600HV0.2 and a depth of >0.015mm. After nitriding, the sealing cone surface of the valve head and the end surface of the valve stem are ground.

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