Check valve and aero-engine

Abstract

The check valve comprises a base, a pin shaft and a pair of valve clacks, the pin shaft penetrates through the pair of valve clacks so that the valve clacks can be rotatably connected relative to the pin shaft, the check valve further comprises a blind hole used for containing one end of the pin shaft, the blind hole is in axial clearance fit with the pin shaft, and the other end of the pin shaft is in threaded connection with the base. The check valve is easy to replace and has good thermal adaptation performance, and the problems that in a traditional check valve structure, a pin shaft is prone to bending deformation after being heated, and the pin shaft is not easy to replace after being abraded can be solved. The invention further provides an aero-engine.

Description

Technical Field

[0001] The present invention relates to the field of aero engines, and in particular to the field of valves. Background Art

[0002] In order to cool the rear bearing casing support plate of the turbine, the rear of the secondary disk, and to supplement the wheel rim seal, the fourth-stage bleed air flow of the compressor is usually led to the rear bearing casing through an external pipeline. During the test run, when the core engine is at a low speed, the pressure at the compressor bleed position is low, sometimes even lower than the ambient pressure, which may cause the core engine air system to not work properly, and even cause the bleed pipe flow path to reverse. If there is fuel in the rear casing of the turbine during the test, the fuel will flow in the reverse direction through the bleed pipe and enter the compressor flow path from the bleed seam, which will bring safety hazards to the core engine. Setting a check valve in the bleed pipe can effectively eliminate this hazard. The existing check valve structure is usually that the two ends of the pin shaft are welded on the base, and the base is welded to the pipeline. The check valve relies on the air flow pressure on both sides to control the opening and closing of the valve disc: when the air flow flows normally, the pressure difference before and after the valve reaches the design value, and the valve disc opens; when the air flow is abnormal, the valve disc closes to prevent the air flow from flowing back.

[0003] The above structure has the following disadvantages: the pin shaft is easily bent and deformed due to factors such as welding and thermal expansion. Since both ends of the check valve pin shaft are welded to the base and the two are fixedly connected, under the action of welding, thermal expansion and other loads, the thermal deformation of the pin shaft and the base after being heated is inconsistent, which easily causes the pin shaft to be bent under force, thereby causing the valve disc to be stuck, affecting the air flow of the air bleed pipeline, and further affecting the performance of the engine; during the engine test run, before operation or at a low speed, the pressure difference before and after the valve does not reach the design value, and the check valve disc is in a closed state. As the speed increases, the pressure difference before and after the valve increases to the design value, and the valve disc rotates around the pin shaft and opens. In this process, wear will inevitably occur between the valve disc and the pin shaft, and as the number of test runs increases, the wear will continue to accumulate, reducing the strength of the pin shaft, and may even cause the pin shaft to break and the valve disc to fall off; when replacing the worn check valve pin shaft, the pipeline needs to be disassembled, and it needs to be re-welded after replacement. In the case where it is inconvenient to disassemble and weld, the entire air bleed pipeline needs to be replaced, which is prone to the problem of pin shaft wear and difficulty in replacement. Summary of the invention

[0004] An object of the present invention is to provide a check valve which is easy to replace and has better thermal adaptability.

[0005] To achieve the above-mentioned purpose, a check valve includes a base, a pin shaft and a pair of valve flaps, wherein the pin shaft passes through the pair of valve flaps so that the valve flaps are rotatably connected relative to the pin shaft. The check valve also includes a blind hole for accommodating one end of the pin shaft, the blind hole and the pin shaft are matched with an axial clearance, and the other end of the pin shaft is threadedly connected to the base.

[0006] In one or more embodiments, the diameter of the pin shaft is smaller than the inner diameter of the blind hole to form a radial gap.

[0007] In one or more embodiments, the check valve further comprises a pin bushing detachably disposed on the base, wherein the pin bushing is used to provide the blind hole.

[0008] In one or more embodiments, the end surface of the pin shaft located outside the base and the end surface of the pin shaft sleeve located outside the base are configured differently.

[0009] In one or more embodiments, the blind hole is disposed on the base.

[0010] In one or more embodiments, the check valve includes a plurality of pins and a plurality of blind holes matched with each of the pins.

[0011] In one or more embodiments, a pair of the valve flaps are arranged opposite to each other, including a pair of protrusions facing each other, and a pin shaft is arranged between the protrusions.

[0012] In one or more embodiments, an annular baffle for limiting the valve flap is also provided on the base.

[0013] In one or more embodiments, the base is further provided with a countersunk hole for matching the pin shaft.

[0014] Another object of the present invention is to provide an aircraft engine, comprising a casing and an air bleed pipeline arranged outside the casing, and also comprising the above-mentioned check valve, one end of which is connected to the air bleed pipeline, and the other end of which is connected to the internal space of the casing.

[0015] The above-mentioned check valve reserves axial expansion space for the pin shaft through a blind hole. Whether in the axial direction or the circumferential direction, there is a certain gap between the pin shaft and the pin shaft sleeve during the entire operation of the engine; a thread is set at one end of the pin shaft, which is screwed in from one side of the base and screwed out from the other side. Through this reversing replacement method, the new pin shaft can be easily replaced without the need to install and remove the valve disc separately. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0017] Figure 1 It is a schematic diagram of the installation position of the check valve;

[0018] Figure 2 is a schematic diagram of an embodiment of a check valve;

[0019] Figure 3 is along Figure 2 Cross-section view in the AA direction;

[0020] Figure 4 is along Figure 2 Cross-section along the middle BB direction;

[0021] Figure 5 yes Figure 4 Enlarged view of point C in the middle;

[0022] Figure 6 is a component exploded view of an embodiment of a check valve;

[0023] Figure 7 It is a schematic diagram of the end grooves of the pin and the pin sleeve.

[0024] Symbols and Markings

[0025] 1 Base

[0026] 2 Pin

[0027] 3 Disc

[0028] 7 Pin Bushing

[0029] 8 Blind holes

[0030] 9 Annular baffle

[0031] 10 Countersunk hole

[0032] 11 Fan

[0033] 12 High pressure compressor

[0034] 13 Combustion Chamber

[0035] 14 High-pressure turbine

[0036] 15 Low-pressure turbine

[0037] 16 Interstage Casing

[0038] 17 Air bleed line

[0039] 18 Check valve

[0040] 21 First pin

[0041] 22 Second pin DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0043] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0044] Figure 1 The schematic structure of the engine is shown, including a fan 11, a high-pressure compressor 12, a combustion chamber 13, a high-pressure turbine 14 and a low-pressure turbine 15, and also an interstage casing 16 and an air bleed line 17. In some embodiments, in order to cool the turbine rear bearing casing support plate, the rear of the secondary disk and supplement the wheel rim seal, the airflow of the compressor is usually led to the location of the interstage casing 16 through the air bleed line 17, and the check valve 18 is arranged at the connection between the air bleed line 17 and the interstage casing 16, and the flow direction of the airflow is controlled by opening and closing the valve flap.

[0045] Aiming at the drawbacks of the existing check valve structure for an aero-engine bleed air pipeline, that the pin shaft is easily bent and deformed after being heated and that the pin shaft is worn and difficult to replace, the present invention proposes a novel check valve structure.

[0046] Reference Figures 2 to 4 As shown, the check valve includes a base 1, a pin shaft 2 and a pair of valve flaps 3. The pin shaft 2 passes through the pair of valve flaps 3 so that the valve flaps 3 are rotatably connected relative to the pin shaft 2. The opening and closing states of the valve flaps 3 are used to realize the on-off of the airflow.

[0047] To facilitate disassembly, the first end of the pin 2 is threadedly connected to the base 1 .

[0048] The check valve further comprises a blind hole 8 for accommodating the second end of the pin 2, and the blind hole 8 is matched with the pin 2 with an axial clearance. Figure 5 As shown in the axial clearance ΔL, preferably, the diameter φd of the pin 2 is smaller than the inner diameter ΦD of the blind hole 8 to form a radial clearance and realize a radial clearance fit. The pin 2 and the blind hole 8 are fitted with a small clearance to ensure the assembly accuracy of the pin.

[0049] In some embodiments, the blind hole 8 is provided by a pin bushing 7 , which is detachably arranged on the base 1 .

[0050] Therefore, the first end of the pin 2 is connected to the base 1 through a thread, and the second end is inserted into the internal blind hole 8 of the pin sleeve 7. A certain space △L is left between the axial end face of the pin 2 and the bottom of the blind hole 8 of the pin sleeve. The blind hole of the pin sleeve and the pin are matched with a small clearance in the radial direction. When the pin and the base are heated and expanded, only the first end of the pin 2 is fastened to the base 1, and the second end is free. Therefore, the pin 2 can expand freely in the axial direction, preventing the axial deformation of the pin and the deformation of the base from being inconsistent under loads such as welding and thermal expansion, resulting in stress concentration problems. Therefore, this structure prevents the pin 2 from being subjected to additional stress caused by the thermal expansion of the base.

[0051] The base 1 is preferably a symmetrical structure, and the structure of the connection between the base 1 and the pin 2 is preferably the same as the structure of the connection between the base 1 and the pin sleeve 7. When replacing the pin 2, first unscrew the pin sleeve 7 from one end, and screw in the new pin 2 from the end where the pin sleeve 7 is located, and simultaneously unscrew the old pin from the threaded end. The screw-out amount of the old pin is consistent with the screw-in amount of the new pin. When the old pin is completely screwed out, the new pin is completely screwed in, and finally the pin sleeve 7 is installed. This reversing replacement method can realize the replacement of the new pin 2 without additional installation and removal of the valve disc 3.

[0052] The end surface of the pin shaft 2 located outside the base 1 and the end surface of the pin shaft sleeve 7 located outside the base are arranged differently, such as Figure 7 As shown, it is convenient to identify the pin and the pin sleeve in the assembled state to prevent incorrect disassembly and assembly when replacing the pin.

[0053] Preferably, countersunk holes 10 are provided on both sides of the base 1, and corresponding bosses 4 are provided on the pin 2 and the pin sleeve 7 respectively. The countersunk holes 10 and the bosses 4 are matched with a small clearance in the radial direction, which plays a guiding role when the pin 2, the pin sleeve 7 and the base 1 are assembled.

[0054] In other embodiments, the blind hole 8 may also be directly disposed on the inner wall of the base 1 .

[0055] Continue back Figures 2 to 4 As shown, the check valve includes a plurality of pins 2 and a plurality of blind holes 8 matched with the pins. The two valve flaps 3 rotate around one of the pins, and the opening and closing angles and positions of the valve flaps 3 are fixed by the other pin. For example, a first pin 21 is arranged at the upper end of the valve flap 3, and a pair of valve flaps 3 are arranged facing each other, including a pair of protrusions 31 facing each other, and a second pin 22 is arranged between the protrusions 31. The first pin 21 plays the role of a rotating shaft hub, and the second pin 22 limits the closing angle of the valve flap 3.

[0056] In order to limit the rotation angle of the valve disc, an annular baffle 9 for limiting the valve disc is also provided on the base 1.

[0057] Thus, during the test, when the airflow flows forward from the compressor to the turbine, the pressure difference before and after the valve reaches the designed value, and the valve disc 3 is forced to rotate and open until it contacts the second pin 22 under the base and stabilizes at the designed opening and closing angle and position. Figure 3 When the airflow flows in the reverse direction from the turbine to the compressor, the valve flap 3 is forced to rotate closed and is restricted by the annular baffle 9, closing the inner cavity of the base 1 to prevent the backflow of airflow.

[0058] During installation, define the upper and lower positions of the base along the air flow direction, and screw the first pin 21 installed on the top from one side of the base 1 to connect the two valve discs 3 in series; after the pin 2 is tightened in place, install and tighten the pin sleeve 7 on the other side of the base 1; the second pin 22 installed at the bottom is screwed in from one side of the base 1, and after being tightened in place, install and tighten the pin sleeve 7 on the other side. Weld the assembled check valve to the air flow pipeline 17, pay attention to the installation direction of the check valve is consistent with the air flow direction of the pipeline, and check whether the check valve disc is flexible to rotate.

[0059] During the test, the temperature of the rear bearing casing rises. When the pin 2 and the base 1 expand due to the heat, only one end of the pin 2 is fastened to the base 1 by a thread, and the other end is at a certain distance from the bottom of the blind hole 8, with a small radial clearance fit, so it is not subject to additional stress caused by the thermal expansion of the base.

[0060] When the pin 2 is damaged due to multiple tests or other reasons and needs to be replaced, if the pin of the series valve disc is replaced, it can be replaced according to Figure 7 Identify the pin and pin sleeve by the end face groove shown. First unscrew the pin sleeve from one end of the base, screw in the new pin from this end, and simultaneously unscrew the old pin from the other end to ensure that the amount of the old pin screwed out is consistent with the amount of the new pin screwed in. When the old pin is completely screwed out, the new pin is completely screwed in, and finally the pin sleeve is installed. There is no need to install or remove the valve disc separately. If replacing a pin that is not connected in series with a valve disc, you can directly unscrew the old pin, install the new pin and tighten it into place.

[0061] Therefore, the check valve overcomes the problems in the traditional check valve structure that the pin shaft is easily bent and deformed after being heated and the pin shaft is difficult to replace due to wear.

[0062] Combined with the introduction of the above-mentioned check valve, it can also be understood that an aircraft engine includes an engine, an air bleed pipeline arranged outside the casing, and the above-mentioned check valve, one end of the check valve is connected to the air bleed pipeline, and the other end is connected to the internal space of the casing. The internal space of the casing refers to the engine chamber area on the radial inner side of the casing.

[0063] It should be noted that the above content uses words such as "first" and "second" to limit components, which is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0064] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0065] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this 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 appropriately combined.

[0066] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A check valve, comprising a base (1), a pin (2) and a pair of valve flaps (3), wherein the pin (2) passes through the pair of valve flaps (3) so that the valve flaps (3) are rotatably connected relative to the pin (2), characterized in that: The check valve further comprises a blind hole (8) for accommodating one end of the pin shaft (2); the blind hole (8) cooperates with the pin shaft (2) with an axial clearance; the other end of the pin shaft (2) is threadedly connected to the base (1).

2. The check valve according to claim 1, characterized in that The diameter of the pin shaft (2) is smaller than the inner diameter of the blind hole (8) to form a radial gap.

3. The check valve according to claim 1, characterized in that The check valve further comprises a pin shaft sleeve (7) detachably arranged on the base, wherein the pin shaft sleeve (7) is used to provide the blind hole (8).

4. The check valve according to claim 3, characterized in that: The end surface of the pin shaft located outside the base and the end surface of the pin shaft sleeve located outside the base are arranged differently.

5. The check valve according to claim 1, characterized in that: The blind hole (8) is arranged on the base (1).

6. The check valve according to claim 1, characterized in that The check valve comprises a plurality of pin shafts (2) and a plurality of blind holes (8) matched with each of the pin shafts.

7. The check valve according to claim 5, characterized in that The pair of valve flaps (3) are arranged facing each other and include a pair of protrusions (31) facing each other. A pin shaft is arranged between the protrusions (31).

8. The check valve according to claim 1, characterized in that The base is also provided with an annular baffle (9) for limiting the valve flap.

9. The check valve according to claim 1, characterized in that: The base is also provided with a countersunk hole for matching the pin shaft.

10. An aircraft engine, comprising a casing and an air bleed line arranged outside the casing, characterized in that: It also includes the check valve as described in claims 1-9, one end of the check valve is connected to the air bleed pipeline, and the other end is connected to the internal space of the casing.

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