Lubricating oil supply and return pipeline structure for turbine ends of small and medium-sized aero-engines

Abstract

The utility model discloses a lubricating oil supply and return pipeline structure for a turbine end of a small and medium-sized aero-engine, which comprises a lubricating oil pipeline, a non-flaring internal thread base, a double-conical-surface sealing clamping sleeve, a non-flaring external thread pipe joint, a non-flaring outer cover nut and a non-flaring pipe joint, a first sealing conical surface is formed at one tail end of the non-flaring external thread pipe joint, and a second sealing conical surface is formed at the other tail end of the non-flaring external thread pipe joint. A second sealing conical surface is formed on the non-flaring internal thread base, a third sealing conical surface and a fourth sealing conical surface are formed at the two tail ends of the double-conical-surface sealing clamping sleeve respectively, a first clamping sleeve inner cutting edge and a second clamping sleeve inner cutting edge are formed on the inner side surface of the double-conical-surface sealing clamping sleeve, and the lubricating oil pipeline is installed in the non-flaring external thread pipe connector. The double-conical-surface sealing clamping sleeve is installed among the non-flaring internal thread base, the non-flaring external thread pipe connector and the lubricating oil pipeline, the first clamping sleeve inner cutting edge and the second clamping sleeve inner cutting edge are embedded into the outer wall of the lubricating oil pipeline, and the third sealing conical surface and the fourth sealing conical surface are tightly attached to the first sealing conical surface and the second sealing conical surface respectively.

Description

Technical fields:

[0001] This utility model relates to a lubricating oil supply and return pipeline structure for the turbine end of a small and medium-sized aero-engine, which belongs to the field of small and medium-sized aero-engines and micro gas turbines. Background technology:

[0002] The lubricating oil system of an aero-engine is one of the core subsystems ensuring stable engine operation, with functions including lubrication, cooling, and corrosion prevention. The lubricating oil circulates and forms an oil film on the surfaces of high-speed rotating bearings, gears, and other friction pairs, reducing wear and carrying away heat generated by friction. Due to their compact structure and high operating temperatures of hot-end components, small and medium-sized engines face challenges in lubricating oil piping design, including space constraints, high-temperature environments, and stringent sealing reliability requirements. The limited internal space of the engine casing makes traditional multi-branch piping layouts difficult to implement, and bent oil pipes are prone to sealing failure due to assembly errors. In existing technologies, lubricating oil piping generally uses hardened stainless steel pipes, which, while heat-resistant, are difficult to straighten. Deviations in machining accuracy can lead to insufficient sealing surface fit during installation, significantly increasing the risk of leakage.

[0003] Therefore, it is indeed necessary to improve existing technologies to address their shortcomings. Utility Model Content:

[0004] This utility model provides a structure for the lubricating oil supply and return pipeline for the turbine end of small and medium-sized aero-engines to solve the problems existing in the prior art.

[0005] This utility model adopts the following technical solution: a lubricating oil supply and return pipeline structure for the turbine end of a small or medium-sized aero-engine, including a lubricating oil pipeline, a non-flared internal thread base, a double-cone sealing sleeve, a non-flared external thread pipe joint, a non-flared outer cover nut, and a non-flared pipe joint. One end of the non-flared external thread pipe joint forms a first sealing cone surface, and the other end of the non-flared external thread pipe joint is equipped with a non-flared outer cover nut and a non-flared pipe joint. After the non-flared internal thread base is installed outside the non-flared external thread pipe joint, one end of the non-flared internal thread base extends beyond the non-flared external thread pipe joint immediately adjacent to that end. The non-flared internal thread base extends beyond the non-flared external thread pipe joint... The outer end of the double-cone sealing sleeve has a second sealing cone surface, and the two ends of the double-cone sealing sleeve have a third sealing cone surface and a fourth sealing cone surface, respectively. The inner surface of the double-cone sealing sleeve has a first inner cutting edge and a second inner cutting edge, respectively, at positions opposite to the third and fourth sealing cone surfaces. The lubricating oil pipeline is installed in a non-flared external threaded pipe joint. The double-cone sealing sleeve is installed between the non-flared internal threaded base, the non-flared external threaded pipe joint, and the lubricating oil pipeline after installation. The first and second inner cutting edges of the sleeve are embedded in the outer wall of the lubricating oil pipeline. The third sealing cone surface is in close contact with the first sealing cone surface, and the fourth sealing cone surface is in close contact with the second sealing cone surface.

[0006] Furthermore, the two ends of the unflared external threaded pipe joint are respectively formed with a first external thread and a second external thread, and the first sealing cone surface is formed at the end of the unflared external threaded pipe joint where the first external thread is located.

[0007] Furthermore, the end of the second external thread portion on the unflared external threaded pipe fitting has an unflared hole.

[0008] Furthermore, a clamping thread is formed on the inner surface of the non-flared internal thread base, which is threadedly engaged with the first external thread and located on one side of the second sealing cone surface. The non-flared internal thread base is tightened together with the non-flared external thread pipe joint by the engagement of the clamping thread with the first external thread.

[0009] Furthermore, the unflared pipe fitting is installed in an unflared hole.

[0010] Furthermore, the unflared outer cover nut is installed and connected to the outside of the unflared external thread pipe joint via a second external thread.

[0011] Furthermore, a flange face is formed on the outer surface of the unflared internal thread base, and the flange face and the second sealing cone face are respectively located on both sides of the clamping thread.

[0012] Furthermore, the aero engine includes an engine casing, and the unflared internal threaded base is connected to the engine casing via a flange face, with a metal sealing ring installed between the flange face and the engine casing for sealing.

[0013] Furthermore, the metal sealing ring is an O-ring or a C-ring.

[0014] Furthermore, there is a 2-4° cone angle difference between the second and fourth sealing cone surfaces.

[0015] This utility model has the following beneficial effects:

[0016] (1) The separate design of the internal lubricating oil pipeline and the unflared external threaded pipe joint of this utility model can solve the problem of oil pipeline assembly in the narrow space of small and medium engines.

[0017] (2) The double conical sealing ferrule adopts a double conical sealing structure. There is a cone angle difference between the double conical sealing ferrule and the sealing cone surface of the unflared internal thread base. This can not only further improve the sealing effect and reduce the machining accuracy requirements of the sealing surface, but also realize the automatic compensation of assembly angle difference. Attached image description:

[0018] Figure 1 This is a schematic diagram of the oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine according to this utility model.

[0019] Figure 2 This is a schematic diagram of a pipe fitting without a flared external thread.

[0020] Figure 3 This is a schematic diagram of a base without a flared internal thread.

[0021] Figure 4 This is a schematic diagram of a nut without a flared outer cover.

[0022] Figure 5 This is a schematic diagram of a non-flared pipe fitting.

[0023] Figure 6 for Figure 1 A schematic diagram showing the engine casing being installed together. Detailed implementation method:

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] This utility model relates to a lubricating oil supply and return pipeline structure for the turbine end of a small and medium-sized aero-engine, comprising a lubricating oil pipeline 7, a non-flared internal thread base 1, a double conical sealing sleeve 2, a non-flared external thread pipe joint 3, a non-flared outer cover nut 4, a non-flared pipe joint 5, and a metal sealing ring 6.

[0026] The two ends of the unflared external threaded pipe connector 3 are respectively formed with a first external thread portion 111 and a second external thread portion 112. A first sealing cone surface 110 is formed at the end where the first external thread portion 111 is located, and an unflared hole 113 is formed at the end where the second external thread portion 112 is located. As one embodiment of the present invention, the inclination angle of the unflared hole 113 is 24°.

[0027] The inner surface of the threadless internal thread base 1 has a clamping thread 102 that engages with the first external thread 111, and a second sealing cone surface 101 located on one side of the clamping thread 102. A flange face 103 is formed on the outer surface of the threadless internal thread base 1, located on the other side of the clamping thread 102. The threadless internal thread base 1 is connected to the engine casing 8 via the flange face 103. Due to the high internal pressure of the engine casing, a metal sealing ring 6 is added between the flange face 103 and the engine casing 8 for sealing. The metal sealing ring 6 can be an O-ring or a C-ring.

[0028] The two ends of the double-cone sealing sleeve 2 are respectively formed with a third sealing cone 121 and a fourth sealing cone 123. A first sleeve inner cutting edge 122 is formed on the inner surface of the double-cone sealing sleeve 2 at a position opposite to the third sealing cone 121, and a second sleeve inner cutting edge 124 is formed on the inner surface of the double-cone sealing sleeve 2 at a position opposite to the fourth sealing cone 123.

[0029] The lubricating oil line 7 is installed in the non-flared external threaded pipe fitting 3. The non-flared internal threaded base 1 is tightened together with the non-flared external threaded pipe fitting 3 by the engagement of the clamping thread 102 and the first external thread 111. After installation, one end of the non-flared internal threaded base 1 extends beyond the non-flared external threaded pipe fitting 3 adjacent to that end.

[0030] The double-cone sealing sleeve 2 is installed between the unflared internal thread base 1, the unflared external thread pipe joint 3, and the lubricating oil line 7 after installation. At this time, under the action of locking force, the inner cutting edge 122 of the first sleeve and the inner cutting edge 124 of the second sleeve are embedded into the outer wall of the lubricating oil line 7. The third sealing cone 121 is in close contact with the first sealing cone 110, and the fourth sealing cone 123 is in close contact with the second sealing cone 101, thereby achieving a sealing effect.

[0031] There is a 2-4° cone angle difference between the second sealing cone surface 101 of the unflared internal thread base 1 and the fourth sealing cone surface 123 of the double-cone sealing sleeve 2. Under pressure, the two sealing cone surfaces exhibit differentiated elastic deformation; the smaller-angle sealing cone surface is more prone to radial displacement, while the larger-angle sealing cone surface focuses on axial deformation. This complementary deformation mechanism reduces stress concentration on the sealing surface, improving the uniformity of contact stress distribution by more than 40%, and further enhancing the sealing effect.

[0032] The flared outer cover nut 4 is installed on the outside of the flared external thread pipe joint 3 via the second external thread 112.

[0033] In the oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine of this utility model, the double-conical sealing sleeve 2 forms a conical contact seal with the second sealing cone 101 inside the unflared internal thread base 1 and the first sealing cone 110 of the unflared external thread pipe joint 3. Under the contact pressure of the second sealing cone 101 and the first sealing cone 110 on both sides, the double-conical sealing sleeve deforms, and the first inner cutting edge 122 and the second inner cutting edge 124 of the double-conical sealing sleeve 2 are embedded into the outer wall of the oil pipeline 7 to form an annular groove, thus constituting a metal-to-metal contact seal between the double-conical sealing sleeve 2 and the oil pipeline 7. The other end of the unflared external thread pipe joint 3, i.e., the unflared hole 113, is equipped with an unflared pipe joint 5, and the unflared outer cover nut 4 is installed on the outside of the unflared pipe joint 5.

[0034] This utility model relates to a lubricating oil supply and return pipeline structure for the turbine end of a small and medium-sized aero-engine. In terms of assembly, thanks to the advantages of the split and layered design, the lubricating oil pipeline 7 can be installed in the unflared external threaded pipe joint 3 inside the engine first, then the unflared internal threaded base 1 can be installed, the lubricating oil pipeline 7 can be passed through the unflared internal threaded base 1, the double conical sealing sleeve 2 can be installed, and the unflared external threaded pipe joint 3 can be tightened to complete the assembly of the lubricating oil pipeline 7.

[0035] In the oil supply and return pipeline structure for the turbine end of a small and medium-sized aero-engine of this utility model, the internal oil pipeline 7 and the unflared external threaded pipe joint 3 are designed separately and adopt a conical sealing structure. There is a 2-4° cone angle difference between the double conical sealing sleeve 2 and the second sealing cone surface 101 of the unflared internal threaded base 1. This can not only further improve the sealing effect and reduce the machining accuracy requirements of the sealing surface, but also realize automatic compensation of assembly angle difference.

[0036] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present utility model, and these improvements should also be considered within the protection scope of the present utility model.

Claims

1. A structure for a lubricating oil supply and return pipeline at the turbine end of a small to medium-sized aero-engine, characterized in that: The system includes a lubricating oil pipeline (7), a non-flared internal thread base (1), a double-cone sealing sleeve (2), a non-flared external thread pipe fitting (3), a non-flared outer cover nut (4), and a non-flared pipe fitting (5). One end of the non-flared external thread pipe fitting (3) has a first sealing cone surface (110). The other end of the non-flared external thread pipe fitting (3) is fitted with a non-flared outer cover nut (4) and a non-flared pipe fitting (5). After the non-flared internal thread base (1) is installed outside the non-flared external thread pipe fitting (3), one end of the non-flared internal thread base (1) extends beyond the non-flared external thread pipe fitting (3) adjacent to that end. The end of the non-flared internal thread base (1) extending beyond the non-flared external thread pipe fitting (3) has a second sealing cone surface (101). The two ends of the double-cone sealing sleeve (2) are respectively formed... The double-cone sealing sleeve (2) has a third sealing cone surface (121) and a fourth sealing cone surface (123). On the inner surface of the double-cone sealing sleeve (2), a first sleeve inner cutting edge (122) and a second sleeve inner cutting edge (124) are formed at positions opposite to the third sealing cone surface (121) and the fourth sealing cone surface (123), respectively. The lubricating oil pipeline (7) is installed in the non-flared external thread pipe joint (3). The double-cone sealing sleeve (2) is installed between the non-flared internal thread base (1), the non-flared external thread pipe joint (3), and the lubricating oil pipeline (7). The first sleeve inner cutting edge (122) and the second sleeve inner cutting edge (124) are embedded in the outer wall of the lubricating oil pipeline (7). The third sealing cone surface (121) is in close contact with the first sealing cone surface (110), and the fourth sealing cone surface (123) is in close contact with the second sealing cone surface (101).

2. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 1, characterized in that: The two ends of the non-flared external threaded pipe joint (3) are respectively formed with a first external thread (111) and a second external thread (112), and the first sealing cone surface (110) is formed at the end of the non-flared external threaded pipe joint (3) where the first external thread (111) is located.

3. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 2, characterized in that: The end of the non-flared external threaded pipe joint (3) where the second external thread (112) is located is formed with a non-flared hole (113).

4. The oil supply and return pipeline structure for the turbine end of a small or medium-sized aero-engine as described in claim 3, characterized in that: The inner surface of the non-flared internal thread base (1) is formed with a clamping thread (102) that is threaded to the first external thread (111) and located on one side of the second sealing cone surface (101). The non-flared internal thread base (1) is tightened together with the non-flared external thread pipe joint (3) by the engagement of the clamping thread (102) with the first external thread (111).

5. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 4, characterized in that: The unflared pipe fitting (5) is installed in the unflared hole (113).

6. The oil supply and return pipeline structure for the turbine end of a small or medium-sized aero-engine as described in claim 5, characterized in that: The unflared outer cover nut (4) is installed on the outside of the unflared external thread pipe joint (3) via the second external thread (112).

7. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 6, characterized in that: The outer surface of the unflared internal thread base (1) is formed with a flange face (103), and the flange face (103) and the second sealing cone face (101) are located on both sides of the clamping thread (102).

8. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 7, characterized in that: The aircraft engine includes an engine casing (8), and the unflared internal threaded base (1) is connected to the engine casing (8) via a flange face (103). A metal sealing ring (6) is installed between the flange face (103) and the engine casing (8) for sealing.

9. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 8, characterized in that: The metal sealing ring (6) is an O-ring or a C-ring.

10. The oil supply and return pipeline structure for the turbine end of a small-to-medium-sized aero-engine as described in claim 9, characterized in that: There is a 2-4° cone angle difference between the second sealing cone surface (101) and the fourth sealing cone surface (123).

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