A bearing device with a common cavity structure

Abstract

This invention pertains to the field of turbine bearing technology, proposing a bearing device with a common cavity structure, comprising: a first bearing housing and a second bearing housing arranged adjacent to each other, coaxially aligned. A first oil return structure is located at the bottom of the first bearing housing, and a second oil return structure is located at the bottom of the second bearing housing. Both the first and second oil return structures are connected to an external oil collection tank. The bottoms of the first and second bearing housings are connected, enabling communication between the first and second oil return structures. By designing the two bearing housings with a bottom-connected structure, the problem of poor oil return is effectively avoided. Regardless of which side of the two bearing housings is higher, the lubricating oil can quickly return to the oil collection tank, meeting the necessary lubrication conditions for normal bearing operation and thus ensuring the safe and reliable operation of the engine.

Description

Technical Field

[0001] This invention belongs to the field of turbine bearing technology, and specifically relates to a bearing device with a common cavity structure. Background Technology

[0002] Existing gas turbine engines are high-temperature, high-pressure, and high-speed rotating machines. To ensure the high-speed rotation of the engine rotor, support bearings must be used at both ends of the rotor. Correspondingly, bearing housings are needed to mount the bearings and transmit the rotor load. At the same time, the bearing housings also need to perform functions such as lubricating the bearings and sealing and cooling them.

[0003] Currently, most gas turbine turboshaft and turboprop engines have two- or even three-stage rotors, requiring a large number of bearings. However, due to space constraints, the internal volume of a single bearing housing is essentially fixed, making it difficult to meet the oil return requirements of helicopter multi-attitude flight. Multiple bearings require separate bearing housings, increasing the number of stator components, engine weight, assembly complexity, cost, and maintainability. Each bearing cavity needs independent lubrication, sealing, and ventilation functions, requiring independent oil supply and return structures, increasing the load and complexity of the accessory lubrication system. The additional sealing bleed air required for multiple bearing housings consumes engine compression power, reducing the mains gas flow and consequently lowering engine power and efficiency. Furthermore, when a helicopter flies in various attitudes, the bearing housing space changes accordingly, potentially causing poor oil return in individual bearing housings. This can lead to lubricating oil not returning to the reservoir in time for the next lubrication cycle, resulting in oil overflow and leakage. In more serious cases, it can cause bearing damage due to lack of lubrication, endangering engine operation. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a bearing device with a common cavity structure, comprising: a first bearing seat and a second bearing seat arranged adjacent to each other, with the first bearing seat and the second bearing seat coaxially arranged; a first oil return structure is provided at the bottom of the first bearing seat; and a second oil return structure is provided at the bottom of the second bearing seat. The first oil return structure and the second oil return structure are respectively connected to an external oil collection tank. The bottoms of the first bearing seat and the second bearing seat are connected, thereby enabling communication between the first oil return structure and the second oil return structure.

[0005] Optionally, it also includes a load-bearing box, the outer wall of the first bearing seat is disposed inside the load-bearing box, the second bearing seat is disposed on the outer wall of the load-bearing box, and a through structure is provided on the bottom of the load-bearing box, the first oil return structure is connected to the second oil return structure through the through structure.

[0006] Optionally, the interior of the second oil return structure has an inclined surface and a horizontal surface, and the inclined surface is close to the second oil return structure.

[0007] Optionally, it also includes an oil return adapter, which is disposed on the second bearing housing. One end of the oil return adapter is connected to the second oil return structure, and the other end is connected to an external oil collection tank.

[0008] Optionally, it also includes an oil return port, which is disposed within the second oil return structure and located at the connection between the oil return adapter and the second oil return structure.

[0009] Optionally, it also includes an oil supply adapter, an oil supply pipe, a first nozzle, and a second nozzle. A portion of the oil supply adapter is disposed in the first bearing housing and connected to the first nozzle, and another portion is disposed in the second bearing housing and communicates with the oil supply pipe. The oil supply pipe is disposed in the second bearing housing, and the second nozzle is connected to the oil supply pipe.

[0010] Optionally, a support structure is also included, one end of which is connected to the second nozzle, and the other end is disposed on the inner wall of the second bearing seat.

[0011] Optionally, it may also include a plurality of auxiliary centering parts, which are respectively disposed on the outer wall of the second bearing housing and parallel to the central axis of the second bearing housing.

[0012] Optionally, the number of auxiliary centering parts is 2-3.

[0013] Optionally, multiple reinforcing ribs may be provided along the axial direction of the second bearing housing.

[0014] The bearing device with a common cavity structure provided by the present invention has the following advantages compared with the prior art:

[0015] A first oil return structure is located at the bottom of the first bearing housing, and a second oil return structure is located at the bottom of the second bearing housing. Both the first and second oil return structures are connected to an external oil collection tank. The bottoms of the first and second bearing housings are also connected, ensuring communication between the two oil return structures. By designing the two bearing housings with a bottom-connected structure, the problem of poor oil return is effectively avoided. Regardless of which side of the two bearing housings is higher, the lubricating oil can quickly return to the oil collection tank, meeting the necessary lubrication conditions for normal bearing operation and thus ensuring the safe and reliable operation of the engine.

[0016] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the bearing device with a common cavity structure in an embodiment of the present invention is shown;

[0019] Figure 2 A schematic diagram of the through-hole structure along direction A of the bearing device with a common cavity structure in an embodiment of the present invention is shown;

[0020] Figure 3 A schematic diagram of the auxiliary centering part of the bearing device with a common cavity structure in an embodiment of the present invention is shown;

[0021] Figure 4 A three-dimensional schematic diagram of the second bearing seat of the bearing device with a common cavity structure in an embodiment of the present invention is shown;

[0022] Figure 5 A side view of the second bearing seat of the bearing device with a common cavity structure in an embodiment of the present invention is shown.

[0023] In the figure, 1. First bearing housing; 2. Second bearing housing; 3. First oil return structure; 4. Second oil return structure; 5. Bearing box; 6. Oil return transition part; 61. Oil return pipe; 62. Oil return transition section; 7. Oil return port; 8. Oil supply transition part; 9. Oil supply pipe; 10. First nozzle; 20. Second nozzle; 30. Support structure; 40. Auxiliary centering part; 50. Through structure; 70. Reinforcing rib. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, this invention provides a bearing device with a common cavity structure, including: a first bearing seat 1 and a second bearing seat 2 arranged adjacent to each other, and the first bearing seat 1 and the second bearing seat 2 are arranged coaxially. A first oil return structure 3 is provided at the bottom of the first bearing seat 1, and a second oil return structure 4 is provided at the bottom of the second bearing seat 2. The first oil return structure 3 and the second oil return structure 4 are respectively connected to an external oil collection tank. The bottoms of the first bearing seat 1 and the second bearing seat 2 are connected, so that the first oil return structure 3 and the second oil return structure 4 are connected. It should be noted that in actual use, the first bearing seat 1 (left bearing seat) and the second bearing seat 2 (right bearing seat) are equivalent to two adjacent left and right bearing seats, each containing a corresponding bearing. When the helicopter is in actual flight, the left and right bearing seats are not always at the same horizontal height; sometimes the left side is higher, and sometimes the right side is higher. In order to ensure that the lubricating oil inside the left and right bearing seats returns to the oil collection tank as quickly as possible, the bottoms of the left and right bearing seats are connected, that is, the two oil return structures are connected through a through structure 50. When the left side is higher than the right side during flight, the lubricating oil in the left bearing housing enters the second oil return structure 4 through the through structure 50. At this time, most of the lubricating oil returns to the oil collection tank through the "7"-shaped oil return pipe 61. When the right side is higher than the left side during flight, correspondingly, most of the lubricating oil returns to the oil collection tank through the gravity-driven first oil return structure 3. Therefore, by designing the left and right bearing housings as a bottom-connected structure, this invention effectively avoids the problem of poor oil return. Regardless of which side is higher, the lubricating oil can quickly return to the oil reservoir, meeting the necessary conditions for normal bearing operation and thus ensuring the safe and reliable operation of the engine. In addition, the structure of this application operates inside the enclosed interior of the engine.

[0026] In one embodiment, a load-bearing housing 5 is also included. The outer wall of the first bearing seat 1 is disposed inside the load-bearing housing 5, and the second bearing seat 2 is disposed on the outer wall of the load-bearing housing 5. A through structure 50 is provided at the bottom of the load-bearing housing 5, and the first oil return structure 3 is connected to the second oil return structure 4 through the through structure 50. The load-bearing housing 5 is a fixed mounting structure for the first bearing seat 1 and also connects the second bearing seat 2 together, especially playing a load-bearing role for the first bearing seat 1. Figure 2 As shown, the through structure 50 is a fan-shaped structure and is located at the bottom of the load-bearing box 5.

[0027] In one embodiment, the interior of the second oil return structure 4 has an inclined surface and a horizontal surface, with the inclined surface close to the second oil return structure 4. The inclined surface allows the oil recovered by the second oil return structure 4 to gather together, that is, a low-lying oil collection structure is formed at the bottom of the second bearing housing 2. When the lubricating oil lubricates the second bearing housing 2, the lubricating oil quickly gathers in the low-lying oil collection structure, which facilitates further collection of the lubricating oil.

[0028] In one embodiment, a return oil transition section 6 is further included. The return oil transition section 6 is disposed on the second bearing housing 2. One end of the return oil transition section 6 is connected to the second return oil structure 4, and the other end is connected to an external oil collection tank. Optionally, the return oil transition structure includes a return oil pipe 61 and a return oil transition section 62 connected together. The return oil pipe 61 is connected to the second return oil structure 4, and the return oil transition section 62 is connected to the external oil collection tank. The return oil pipe 61 is in the shape of a "7" or an L. The return oil pipe 61 is not located directly below the second bearing housing 2, but is arranged on the side at an angle of 30 to 45 degrees to the direct below. After passing through the return oil transition section 62, it finally enters the oil collection tank through an external pipeline, thereby completing the return oil of the second bearing housing 2. For the first bearing housing 1, a gravity return oil structure (first return oil structure 3) is designed directly at the bottom (in the direction of gravity). The external pipeline is connected to the interface of the gravity return oil structure, and the lubricating oil also enters the oil collection tank, thereby completing the return oil of the second bearing housing 2.

[0029] In one embodiment, an oil return port 7 is also included. The oil return port 7 is disposed within the second oil return structure 4 and is located at the connection between the oil return transition section 6 and the second oil return structure 4. Specifically, the oil return port 7 is located at the outlet end of the second oil return structure 4. It should be noted that the lubricating oil rapidly gathers at the low-lying position of the second oil return structure 4. Because the lubricating oil gathers at the low-lying position, the lubricating oil level is high, so a small amount of lubricating oil can submerge the oil return port 7. The oil return port 7 has an oil suction pump. Under the suction force of the oil suction pump, the lubricating oil is sucked into the oil return transition section 6, that is, sequentially sucked into the oil return pipe 61 and the oil return transition section 62, and finally arrives in the oil collection tank.

[0030] In one embodiment, the system further includes an oil supply adapter 8, an oil supply pipe 9, a first nozzle 10, and a second nozzle 20. A portion of the oil supply adapter 8 is disposed within the first bearing housing 1 and connected to the first nozzle 10, while another portion is disposed within the second bearing housing 2 and communicates with the oil supply pipe 9. The oil supply pipe 9 is disposed within the second bearing housing 2, and the second nozzle 20 is connected to the oil supply pipe 9. Optionally, the first nozzle 10 and the second nozzle 20 are both identical boss-shaped fuel injectors. When the engine is running, bearing lubricating oil reaches the oil supply adapter 8 through an external pipeline, and then splits into left and right paths. The oil flows to the left through the internal pipeline of the first bearing housing 1 and is sprayed onto the left bearing via the boss-shaped fuel injector (first nozzle 10), satisfying the lubrication requirements of the left bearing. The oil flows to the right through the "7"-shaped or L-shaped oil supply pipe 9 of the second bearing housing 2 and is sprayed onto the right bearing via the boss-shaped fuel injector (second nozzle 20), satisfying the lubrication requirements of the right bearing. For a closed lubrication system of an engine, the total amount of lubricating oil is fixed. After the lubricating oil lubricates the bearing through the nozzle, it should return to the oil tank as soon as possible to meet the requirements of continuous and circulating lubrication. This is a necessary condition for the normal operation of the bearing. If the bearing lacks lubrication within 30 seconds, it is very easy to cause bearing damage, which will lead to the failure of the engine's rotor system and endanger the safe operation of the entire engine. Therefore, the structural design of the oil return system is crucial.

[0031] In one embodiment, a support structure 30 is further included. One end of the support structure 30 is connected to the second nozzle 20, and the other end is disposed on the inner wall of the second bearing seat 2. It should be noted that, due to the high lubricating oil pressure, and in order to prevent the boss injector (second nozzle 20) from developing fatigue cracks and leaking oil due to vibrations generated during engine operation, a buttress support structure 30 is added near the second nozzle 20 to increase the rigidity of the boss injector (second nozzle 20) and make it more stable.

[0032] like Figure 3 As shown, in one embodiment, it further includes a plurality of auxiliary centering parts 40, which are respectively disposed on the outer wall of the second bearing housing 2 and parallel to the central axis of the second bearing housing 2. It should be noted that vibration is inevitable during engine operation, and the rear bearing housing in this invention needs to transmit a large axial force. To ensure a low vibration level in the engine and smooth force transmission in the rear bearing housing, this invention also provides an auxiliary centering part 40 for the bearing housing mounting edge, such as... Figure 3 As shown, the auxiliary centering part 40 is a tapered locating pin. Its left side is interference-fitted onto the mounting edge of the second bearing housing 2 to form an integral part. The tapered surface on the right side is used to guide the alignment with the mounting section during assembly. The cylindrical surface and the cylindrical surface of the mounting section fit precisely together, playing the role of auxiliary centering.

[0033] In one embodiment, the number of auxiliary centering parts 40 is 2-3. It should be noted that the auxiliary centering parts 40 are locating pins, and the number of locating pins is generally 2-3, and should not exceed 3, to prevent over-constraint. Based on actual usage, without the auxiliary centering parts 40, the vibration is 16-19 mm / s. After adding two auxiliary centering parts 40, the vibration level at the same location drops to less than 10 mm / s, a very significant reduction. This prevents fatigue damage to bolts, load-bearing components, and other parts of the engine due to excessive vibration, ensuring stable, safe, and reliable engine operation.

[0034] like Figure 4 As shown, in one embodiment, multiple reinforcing ribs 70 are arranged along the axial direction of the second bearing housing 2. Specifically, the second bearing housing 2 in this invention has a relatively large length-to-diameter ratio and is relatively "flexible," but it needs to transmit the axial force from the load-bearing box 5 and the first bearing housing 1 to the mounting section (the mounting section is the object that mates with the rear bearing housing, not shown in the figure). This axial force is relatively large. To ensure that the second bearing housing 2 meets the requirements for rigidity, strength, and service life, reinforcing ribs 70 are designed. The reinforcing ribs 70 are arranged in parallel along the axial direction. The reinforcing ribs 70 are generally cuboid structures, but can also be cylindrical, triangular prisms, or other strip structures. The number and cross-sectional dimensions of the reinforcing ribs 70 (e.g., ...) are also considered. Figure 5 The values ​​of m (width) and n (thickness) should be determined according to the following calculation requirements:

[0035] (1) Stiffness requirements: Stiffness calculation formula

[0036] In the formula:

[0037] F—force, N; L—displacement in the direction of F, m;

[0038] To meet the overall deformation resistance requirements, the stiffness must be greater than or equal to 5×107 N / m.

[0039] (2) Strength requirements:

[0040] Yield strength reserve factor:

[0041] Ultimate strength reserve coefficient:

[0042] In the formula:

[0043] —Nominal yield strength, MPa;

[0044] —Ultimate tensile strength, MPa;

[0045] —Maximum equivalent stress, MPa;

[0046] K—casting coefficient, with a value range of 1.2 to 1.5.

[0047] (2) Lifespan requirements:

[0048] Estimating the low-cycle fatigue life of the right bearing housing using the general slope method

[0049]

[0050] In the formula:

[0051] —Strain range;

[0052] —Reduction of area, %

[0053] —Persistent strength, MPa;

[0054] —Mean stress, MPa;

[0055] E—elastic modulus, GPa;

[0056] —Low cycle fatigue life, times.

[0057] To meet the ever-increasing demands for high performance and long lifespan in aero engines, the low-cycle fatigue life should be no less than 20,000 cycles.

[0058] In addition to meeting the above requirements, the number and cross-sectional dimensions of the reinforcing ribs 70 must also meet the weight limit requirements of the parts. Depending on the actual use, the number of reinforcing ribs 70 is generally 6 to 8, and the cross-sectional dimensions are generally 15mm × 8mm (length × width).

[0059] In summary, the common cavity structure of the bearing housing provided by this invention ensures smooth oil return for the helicopter in all flight attitudes by designing two bearing housings with a common cavity. Regardless of which side of the two bearing housings is higher, the lubricating oil can quickly return to the oil tank, meeting the necessary lubrication conditions for normal bearing operation and thus ensuring the safe and reliable operation of the engine. At the same time, the addition of an auxiliary centering part 40 ensures a tight fit during engine operation, reducing engine vibration levels. Furthermore, a reinforcing rib 70 is designed on the outer surface of the second bearing housing 2 to prevent damage to the rear bearing housing from large axial forces, ensuring stable power transmission of the engine.

[0060] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bearing device with a common cavity structure, characterized in that, include: The first bearing seat (1) and the second bearing seat (2) are arranged adjacent to each other, and the first bearing seat (1) and the second bearing seat (2) are arranged on the same axis. A first oil return structure (3) is provided at the bottom of the first bearing seat (1), and a second oil return structure (4) is provided at the bottom of the second bearing seat (2). The first oil return structure (3) and the second oil return structure (4) are respectively connected to an external oil collection tank. The bottoms of the first bearing seat (1) and the second bearing seat (2) are connected, so that the first oil return structure (3) and the second oil return structure (4) are connected. The first oil return structure (3) is a gravity oil return structure under the gravity direction of the first bearing seat (1); it also includes an oil return adapter (6), which includes a connected oil return pipe (61) and an oil return adapter section (62). The oil return pipe (61) is L-shaped or 7-shaped and is connected to the second oil return structure (4). The oil return adapter section (62) is connected to an external oil collection tank, and the oil return pipe (61) is located on the side of the second bearing seat (2) at an angle of 30-45°.

2. The bearing device with a common cavity structure according to claim 1, characterized in that, It also includes a load-bearing box (5), the outer wall of the first bearing seat (1) is located inside the load-bearing box (5), the second bearing seat (2) is located on the outer wall of the load-bearing box (5), a through structure (50) is provided on the bottom of the load-bearing box (5), and the first oil return structure (3) is connected to the second oil return structure (4) through the through structure (50).

3. The bearing device with a common cavity structure according to claim 1, characterized in that, The interior of the second oil return structure (4) has an inclined surface and a horizontal surface, and the inclined surface is close to the second oil return structure (4).

4. The bearing device with a common cavity structure according to claim 1, characterized in that, The oil return adapter (6) is disposed on the second bearing seat (2). One end of the oil return adapter (6) is connected to the second oil return structure (4), and the other end is connected to the external oil collection tank.

5. The bearing device with a common cavity structure according to claim 4, characterized in that, It also includes an oil return port (7), which is disposed in the second oil return structure (4) and is located at the connection between the oil return adapter (6) and the second oil return structure (4).

6. The bearing device with a common cavity structure according to claim 1, characterized in that, It also includes an oil supply adapter (8), an oil supply pipe (9), a first nozzle (10) and a second nozzle (20). A part of the oil supply adapter (8) is disposed in the first bearing housing (1) and connected to the first nozzle (10), and the other part is disposed in the second bearing housing (2) and connected to the oil supply pipe (9). The oil supply pipe (9) is disposed in the second bearing housing (2), and the second nozzle (20) is connected to the oil supply pipe (9).

7. The bearing device with a common cavity structure according to claim 6, characterized in that, It also includes a support structure (30), one end of which is connected to the second nozzle (20), and the other end is disposed on the inner wall of the second bearing seat (2).

8. The bearing device with a common cavity structure according to claim 1, characterized in that, It also includes a plurality of auxiliary centering parts (40), which are respectively disposed on the outer wall of the second bearing seat (2) and parallel to the central axis of the second bearing seat (2).

9. The bearing device with a common cavity structure according to claim 8, characterized in that, The number of auxiliary centering parts (40) is 2-3.

10. The bearing device with a common cavity structure according to claim 1, characterized in that, Multiple reinforcing ribs (70) are provided along the axial direction of the second bearing housing (2).

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