Aero-engine accessory casing tail shaft fixing structure

Abstract

The invention belongs to the field of cartridge receiver design, and particularly relates to an aero-engine accessory cartridge receiver tail shaft fixing structure which comprises a rotor assembly, a sealing unit and an accessory cartridge receiver. The rotor assembly and the sealing unit are both arranged in the accessory casing. The rotor assembly comprises a gear shaft, a tail shaft, a first bearing, a second bearing and a third bearing. The end of the tail shaft is connected with the front end of the gear shaft, the first bearing is connected with the gear shaft, the second bearing and the third bearing are connected with the tail shaft, the second bearing is arranged between the first bearing and the third bearing, and the sealing unit is arranged at one end of the tail shaft. After a two-section structure and three bearings are adopted for supporting, the device is suitable for a slender structure with L larger than or equal to 1.5 D, and the working margin and the bearing capacity are more stable. The tail shaft, the gear, the seal and other parts form a unit body structure and become an internal and external field replaceable unit, so that the maintainability is better; the tail shaft spline is arranged near the middle point of the gear shaft supporting bearing, and the abrasion resistance of the spline pair is improved.

Description

Technical Field

[0001] This application belongs to the field of casing design, and specifically relates to a tail shaft fixing structure for an aero-engine accessory casing. Background Technology

[0002] To facilitate the layout of aircraft and engine accessories (fuel pump, hydraulic pump, generator, etc.) and control the engine's radial profile, an aircraft accessory housing 11 (hereinafter referred to as "aircraft accessory") and an engine accessory housing 12 (hereinafter referred to as "engine accessory") are generally provided. The aircraft accessory is fixed to the aircraft's load-bearing frame, and the engine accessory is fixed to the outside of the engine compressor. To accommodate load deformation under different installation references, the aircraft accessory and the engine accessory are connected by a flexible coupling 13 with angle compensation function. See [link to relevant documentation]. Figure 1 .

[0003] The part connecting the accessory housing and the flexible coupling is called the tail shaft. The tail shaft structure of the aircraft and engine has one end fully constrained and the other end axially floating. The structure of the fully constrained tail shaft end is shown in [reference needed]. Figure 2 The fully constrained end is secured to the fly attachment drive rod inside the fly attachment gear shaft by fastening nuts and spacer sleeves, and then fixed to the fly attachment housing by support bearings at both ends of the fly attachment gear shaft.

[0004] Figure 2 The structure is generally suitable for situations where dimensions L and D satisfy L < 1.5D. When L ≥ 1.5D, the tail shaft drive rod will become slender, and the critical speed margin will be greatly reduced. When the first-order critical speed margin is less than 20%, the system will not be able to work stably. In addition, after the rotor becomes slender, the radial load of the first support bearing will increase sharply, while the radial load of the second support bearing will decrease sharply. The bearing is prone to problems such as excessive contact stress and slippage under light load, which reduces reliability.

[0005] Therefore, how to improve the critical speed margin at the fully constrained end of the tail shaft is a problem that needs to be solved. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a tail shaft fixing structure for an aero-engine accessory casing, thereby resolving the problem of insufficient critical speed margin at the fully constrained end of the tail shaft in the prior art.

[0007] The technical solution of this application is: a tail shaft fixing structure for an aero-engine accessory housing, including a rotor assembly, a sealing unit and an accessory housing;

[0008] The rotor assembly and sealing unit are both located inside the accessory housing. The rotor assembly includes a gear shaft, a tail shaft, a first bearing, a second bearing, and a third bearing. The end of the tail shaft is connected to the front end of the gear shaft. The first bearing is connected to the gear shaft. The second and third bearings are connected to the tail shaft. The second bearing is located between the first and third bearings. The sealing unit is located at one end of the tail shaft.

[0009] The first and second bearings together bear the radial load generated by the gear meshing of the gear shaft, while the third bearing bears the axial load generated by the reference load.

[0010] Preferably, the distance between the first bearing and the second bearing differs from the gear distance of the gear shaft within a set range.

[0011] Preferably, the third bearing is a thrust bearing, and the thrust bearing is connected to the tail shaft by a fastening nut.

[0012] Preferably, the tail shaft and the gear shaft are connected by an involute spline pair, which is located at the midpoint between the first bearing and the second bearing, and the spline pair is provided with a cylindrical positioning surface.

[0013] Preferably, the sealing unit includes a sealing assembly and a sealing mounting seat; the sealing assembly is connected to the front end of the third bearing, the sealing mounting seat is detachably connected to the tail shaft and sleeved on the outside of the sealing assembly, and the sealing mounting seat is fixed to the housing of the accessory housing by threaded fasteners.

[0014] Preferably, a bearing mounting seat is provided on the outer side of the third bearing, and the bearing mounting seat is fixedly connected to the sealing mounting seat.

[0015] This application has the following advantages:

[0016] With a two-section structure and 3 bearings for support, it is suitable for slender structures with L≥1.5D, and has a more stable working margin and load-bearing capacity;

[0017] The tail shaft, gears, seals and other components form a unit structure, which can be replaced in the indoor and outdoor fields, and has better maintainability.

[0018] The tail shaft spline is located near the midpoint of the gear shaft support bearing to improve the wear resistance of the spline pair. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the flying attachment and launch attachment connection structure in the background art;

[0020] Figure 2 This is a schematic diagram of a fully constrained tail shaft structure in the background art;

[0021] Figure 3 This is a schematic diagram of the overall structure of this application.

[0022] 1. First bearing; 2. Gear shaft; 3. Tail shaft; 4. Second bearing; 5. Accessory housing; 6. Fastening nut; 7. Third bearing; 8. Bearing mount; 9. Sealing assembly; 10. Sealing mount; 11. Aircraft accessory housing; 12. Engine accessory housing; 13. Flexible coupling. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0024] The first aspect of this application provides a tail shaft fixing structure for an aircraft engine accessory casing, such as... Figure 3 As shown, settings Figure 3 The right side of the image represents the front end, and the left side represents the back end.

[0025] Includes rotor assembly, sealing unit, and accessory housing 5;

[0026] The rotor assembly and sealing unit are both located inside the accessory housing 5. The rotor assembly includes a gear shaft 2, a tail shaft 3, a first bearing 1, a second bearing 4, and a third bearing 7. The end of the tail shaft 3 is connected to the front end of the gear shaft 2. The first bearing 1 is connected to the gear shaft 2. The second bearing 4 and the third bearing 7 are connected to the tail shaft 3. The second bearing 4 is located between the first bearing 1 and the third bearing 7. The sealing unit is located at one end of the tail shaft 3.

[0027] The first bearing 1 and the second bearing 4 together bear the radial load generated by the gear meshing of the gear shaft 2, and the third bearing 7 bears the axial load generated by the reference load.

[0028] By connecting the gear shaft 2 to the tail shaft 3, the overall structure of the rotor assembly is lengthened, and an additional bearing is added, which improves the rigidity of the rotor system and increases the critical speed margin of the rotor.

[0029] The first bearing 1 and the second bearing 4 together bear the radial load, while the third bearing 7 bears the axial load, thus improving the load-bearing capacity.

[0030] Preferably, the distance between the first bearing 1 and the second bearing 4 is within a set range from the gear distance of the gear shaft 2. This set range is much smaller than the distance between the first bearing 1 and the second bearing 4, ensuring that the distance between the first bearing 1 and the second bearing 4 is comparable to the gear distance of the gear shaft 2, thereby achieving comparable load, compact structure, and strong load-bearing capacity.

[0031] Preferably, the third bearing 7 is a thrust bearing, which is connected to the tail shaft 3 by a fastening nut 6. The third bearing 7 avoids slippage under light loads by bearing the axial load generated by the reference load.

[0032] Preferably, the tail shaft 3 and the gear shaft 2 are connected by an involute spline pair. The spline pair is located at the midpoint of the first bearing 1 and the second bearing 4. The spline pair is provided with a cylindrical positioning surface to avoid slight wear of the spline pair.

[0033] Preferably, the sealing unit includes a sealing component and a sealing mounting seat 10; the sealing component is connected to the front end of the third bearing 7, the sealing mounting seat 10 is detachably connected to the tail shaft 3 and sleeved on the outside of the sealing component, and the sealing mounting seat 10 is fixed to the housing of the accessory housing 5 by threaded fasteners. While sealing the structure on the tail shaft 3, the tail shaft 3 component can be directly replaced in the inner and outer fields, which is convenient for maintenance.

[0034] Preferably, a bearing mounting seat 8 is provided on the outer side of the third bearing 7. The bearing mounting seat 8 is fixedly connected to the sealing mounting seat 10. The bearing bearing capacity of the third bearing 7 is enhanced by supporting the bearing mounting seat 8.

[0035] In summary, this application has the following advantages:

[0036] With a two-section structure and three bearing supports, this invention is applicable to Figure 3 The slender structure with L≥1.5D has a more stable working margin and load-bearing capacity;

[0037] The tail shaft, gears, seals and other components form a unit structure, which can be replaced in the indoor and outdoor fields, and has better maintainability.

[0038] The tail shaft spline is located near the midpoint of the gear shaft support bearing to improve the wear resistance of the spline pair.

[0039] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An aircraft engine accessory gearbox tail shaft fixation structure, characterized by, The rotor assembly, the sealing unit and the accessory case (5) are included. The rotor assembly and the sealing unit are arranged in the accessory case (5), the rotor assembly includes a gear shaft (2), a tail shaft (3), a first bearing (1), a second bearing (4) and a third bearing (7), the end of the tail shaft (3) is connected with the front end of the gear shaft (2), the first bearing (1) is connected with the gear shaft (2), the second bearing (4) and the third bearing (7) are connected with the tail shaft (3), the second bearing (4) is arranged between the first bearing (1) and the third bearing (7), and the sealing unit is arranged at one end of the tail shaft (3). The first bearing (1) and the second bearing (4) jointly bear the radial load generated by gear meshing of the gear shaft (2), and the third bearing (7) bears the axial load generated by the reference load.

2. The gas turbine engine accessory gearbox tail shaft fixation structure as in claim 1, wherein, The distance between the first bearing (1) and the second bearing (4) is within a set range from the gear distance of the gear shaft (2).

3. The gas turbine engine accessory gearbox tail shaft fixation structure as in claim 1, wherein, The third bearing (7) is a thrust bearing, and the thrust bearing is connected with the tail shaft (3) through a fastening nut (6).

4. The gas turbine engine accessory gearbox tail shaft fixation structure as in claim 1, wherein, The tail shaft (3) and the gear shaft (2) are connected through an involute spline pair, the spline pair is arranged at the midpoint position of the first bearing (1) and the second bearing (4), and a cylindrical positioning surface is arranged on the spline pair.

5. The gas turbine engine accessory gearbox tail shaft fixation structure as in claim 1, wherein, The sealing unit includes a sealing assembly and a sealing mounting seat (10), the sealing assembly is connected to the front end of the third bearing (7), the sealing mounting seat (10) is detachably connected with the tail shaft (3) and is sleeved outside the sealing assembly, and the sealing mounting seat (10) is fixed on the housing of the accessory case (5) through a threaded fastener.

6. The gas turbine engine accessory gearbox tail shaft fixation structure as in claim 5, wherein, An outer side of the third bearing (7) is provided with a bearing mounting seat (8), and the bearing mounting seat (8) is fixedly connected with the sealing mounting seat (10).

Images