Aero-engine accessory casing bearing fastening structure

Abstract

The invention belongs to the field of cartridge receiver design, and particularly relates to an aero-engine accessory cartridge receiver bearing fastening structure which comprises a cartridge receiver shell, a gear shaft, a first bearing, a second bearing, a first bush and a second bush. Flanges are arranged on the outer rings of the first bearing and the second bearing, the flanges are connected with the casing shell through threaded fasteners, and the first lining and the second lining are both of an aluminum alloy structure. A bearing fastening structure combining bearing outer ring flange fixation and an aluminum alloy lining avoids maintenance and scrapping of the casing shell, the repair cost is reduced, meanwhile, fretting wear of a bearing outer ring can be effectively restrained, the bearing positioning precision is improved, and early failure of a bearing and a gear is avoided; the bearing bush and the casing shell form an annular oil way, the oil supply hole is formed in the bush, the bearing is lubricated and cooled, and compared with oil spraying of an external nozzle, the structure is more compact and simpler, and reliability is high; the material is especially suitable for use under high environment temperature conditions.

Description

Technical Field

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

[0002] An aircraft engine accessory housing is a gear transmission box consisting of a series of cylindrical or bevel gears, accessory mounting seats, a housing shell, and support bearings. It is used to fasten lubricating oil accessories and starters to the aircraft and engine, transmit power from the engine main shaft to drive the accessories, and provide energy to the aircraft; it also transmits starter power to start the engine. Poor lubrication leading to premature bearing failure is a common fault in accessory housings. Wear and deformation of the housing shell after use result in a high scrap rate, which is a major factor affecting the maintenance cost of accessory housings. A typical fastening structure for the bearings inside the accessory housing is shown below. Figure 1 .

[0003] Bearings are typically equipped with forced lubrication nozzles, but the complex nozzle structure prevents complete coverage of the internal casing, limiting the use of this design. To facilitate maintenance, a bushing is usually placed between the housing and the bearing; however, during bearing operation, fretting wear between the outer ring and the bushing cannot be effectively suppressed, resulting in a significant decrease in bearing positioning accuracy.

[0004] Turbofan engines typically operate stably below Mach 1.8, while the accessory casing is subjected to ambient temperatures of 120°C for extended periods. Figure 1 The structure shown is adequate; however, for hypersonic vehicles, which generally operate at Mach 2 or higher, the accessory housing is subjected to an ambient temperature of 300°C for extended periods. Figure 1 The defects of the structure shown are becoming increasingly apparent.

[0005] Figure 1 An aluminum alloy bearing bushing is installed between the bearing and the casing in the structure. The purpose is to replace the bushing during repairs to avoid scrapping the casing and reduce repair costs. However, this structure cannot prevent fretting wear between the bearing outer ring and the bushing. Wear of the aluminum alloy bushing will lead to a decrease in bearing positioning accuracy, which in turn will cause premature fatigue damage to the gears and bearings. The bushing can be made of surface-hardened structural steel and titanium alloy to suppress wear, but its coefficient of linear expansion cannot be perfectly matched with the casing material (generally cast magnesium alloy or aluminum alloy) and bearing steel. Under high temperature conditions, it will still affect the bearing positioning accuracy.

[0006] In one specific design, the outer ring of the bearing is fastened to the casing using a flange structure, which avoids wear problems. However, the repair cost is relatively high. Since the outer ring of the bearing is in contact with the casing, it is inevitable that the casing needs to be re-machined during repair. After use under harsh conditions, the casing may become unusable.

[0007] Figure 1The structure shown has nozzles for oil lubrication on the outside or inside of the bearing. The lubricating oil between the bearing and the casing cannot be discharged efficiently. Under high temperature and high speed conditions, the bearing temperature rises too quickly due to the oil stirring, which can easily lead to high temperature discoloration.

[0008] Therefore, improving the wear resistance of the accessory housing is a problem that needs to be solved. Summary of the Invention

[0009] To address the aforementioned issues, this application provides a bearing fastening structure for an aero-engine accessory housing, thereby resolving the problem of accessory housings being prone to failure under hypersonic conditions in the prior art.

[0010] The technical solution of this application is: a fastening structure for an aero-engine accessory casing bearing, including a casing housing, a gear shaft, a first bearing, a second bearing, a first bushing, and a second bushing;

[0011] The casing housing consists of two sets, which are respectively located at both ends of the gear shaft. One end of the gear shaft is connected to one set of casing housings via a first bearing, and the other end is connected to the casing housing via a second bearing.

[0012] The first bushing is disposed between the first bearing and the casing housing, and the second bushing is disposed between the second bearing and the casing housing;

[0013] The outer rings of the first and second bearings are provided with flanges, which are connected to the housing by threaded fasteners. Both the first and second bushings are made of aluminum alloy.

[0014] Preferably, a first annular oil passage is provided between the first bushing and the casing housing, and a second annular oil passage is provided between the second bushing and the casing housing. Cooling oil can be introduced into the first annular oil passage and the second annular oil passage. The first bushing and the second bushing are provided with oil supply holes that communicate with the first annular oil passage or the second annular oil passage.

[0015] Preferably, the casing is provided with an oil drain port and a vent, the oil drain port being located in the lower part of the bearing cavity of the first bearing or the second bearing, and the vent being located in the upper part of the bearing cavity of the first bearing or the second bearing.

[0016] Preferably, the angle between the middle position of the oil leak and the vertical direction is: L2=(L3+L4) / 2;

[0017] In the formula, L2 is the distance from the first gear to the center of the gear, L3 is the outer ring diameter of the first gear, and L4 is the inner ring diameter of the first gear;

[0018] The cross-section of the gear at the oil leak port satisfies the following formula:

[0019] ;

[0020] In the formula, L1 is the length of the oil leak, L5 is the depth of the oil leak, and Q is the oil supply.

[0021] Preferably, the angle between the location of the vent and the vertical direction is within ±60°, and the cross-sectional area is not less than 1 / 2 of the cross-sectional area of ​​the oil leak.

[0022] Preferably, the first bushing and the first bearing, and the second bushing and the outer ring of the second bearing are all clearance fits; the first bushing and the second bushing are interference fits with the casing.

[0023] The aircraft engine accessory housing bearing fastening structure of this application has the following advantages:

[0024] The bearing fastening structure combining the outer ring flange fixation and the aluminum alloy bushing avoids the maintenance and scrapping of the casing, reducing repair costs. At the same time, it can effectively suppress the fretting wear of the outer ring of the bearing, improve the bearing positioning accuracy, and avoid premature failure of the bearing and gear.

[0025] The bearing bushing and the casing housing form an annular oil passage. An oil supply hole is provided on the bushing to lubricate and cool the bearing. Compared with external nozzle oil spraying, the structure is more compact, simple, and reliable; it is especially suitable for use under high ambient temperature conditions.

[0026] The bearing cavity is equipped with an oil drain port and a ventilation port to facilitate oil return and prevent oil churning. At the same time, a design method for the structural dimensions of the oil drain port is proposed, which is efficient, reliable and practical. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a bearing bushing made of aluminum alloy placed between the bearing and the casing in the background art.

[0028] Figure 2 This is a schematic diagram of a bearing outer ring fastened to the casing using a flange structure in the background art;

[0029] Figure 3 This is a schematic diagram of the overall structure of this application;

[0030] Figure 4 for Figure 3 Schematic diagram of the AA structure;

[0031] Figure 5 for Figure 4 Schematic diagram of the BB structure;

[0032] Figure 6 This diagram shows the arrangement of the first bushing, the casing, and the first annular oil passage in this application.

[0033] 1. First bushing; 2. Casing housing; 3. First bearing; 4. Threaded fastener; 5. Second bushing; 6. First annular oil passage; 7. Gear shaft; 8. Second bearing; 9. Second annular oil passage; 10. Oil supply nozzle. Detailed Implementation

[0034] 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.

[0035] The first aspect of this application provides a fastening structure for an aircraft engine accessory casing bearing, including a casing housing 2, a gear shaft 7, a first bearing 3, a second bearing 8, a first bushing 1, and a second bushing 5;

[0036] There are two sets of housing 2, which are respectively located at both ends of the gear shaft 7. One end of the gear shaft 7 is connected to one set of housing 2 through a first bearing 3, and the other end is connected to the housing 2 through a second bearing 8.

[0037] The first bushing 1 is located between the first bearing 3 and the casing 2, and the second bushing 5 is located between the second bearing 8 and the casing 2;

[0038] The outer rings of the first bearing 3 and the second bearing 8 are provided with flanges, which are connected to the casing 2 by threaded fasteners 4. The first bushing 1 and the second bushing 5 are both made of aluminum alloy.

[0039] The aluminum alloy bushing serves two purposes: it can be replaced during maintenance to reduce the scrap rate of the casing 2 and control maintenance costs; the bushing and the casing 2 form an annular oil passage to provide cooling for the bearings and the housing, which is especially suitable for use in high ambient temperatures.

[0040] The outer ring fretting wear is suppressed by setting up a flange.

[0041] The bearing fastening structure, which combines an outer ring flange and an aluminum alloy bushing, avoids the need for maintenance and scrapping of the casing 2, reducing repair costs. At the same time, it can effectively suppress fretting wear on the outer ring of the bearing, improve bearing positioning accuracy, and prevent premature failure of the bearing and gears.

[0042] Preferably, a first annular oil passage 6 is provided between the first bushing 1 and the casing 2, and a second annular oil passage 9 is provided between the second bushing 5 and the casing 2. Cooling oil can be introduced into the first annular oil passage 6 and the second annular oil passage 9. The first bushing 1 or the second bushing 5 is provided with an oil supply nozzle 10 that communicates with the first annular oil passage 6 or the second annular oil passage 9. The first bushing 1 and the second bushing 5 are provided with an oil supply hole that communicates with the first annular oil passage 6 or the second annular oil passage 9.

[0043] By setting up the first annular oil passage 6 and the second annular oil passage 9, the casing 2, the first bearing 3 and the second bearing 8 can be cooled simultaneously. Compared with external nozzle oil spraying, the structure is more compact, simple and reliable; it is especially suitable for use under high ambient temperature conditions.

[0044] Preferably, the first bushing 1 and the first bearing 3, and the second bushing 5 and the outer ring of the second bearing 8 are all fitted with clearance; the first bushing 1 and the second bushing 5 are fitted with the casing 2 with interference fit.

[0045] Preferably, the casing 2 is provided with an oil drain port and a vent. The oil drain port is located in the lower part of the bearing cavity of the first bearing 3 or the second bearing 8, and the vent is located in the upper part of the bearing cavity of the first bearing 3 or the second bearing 8. By providing an oil drain port and a vent, oil return is facilitated and oil churning is avoided. At the same time, a design method for the structural dimensions of the oil drain port is proposed, which is efficient, reliable, and practical.

[0046] The angle between the middle position of the oil leak and the vertical direction is: L2=(L3+L4) / 2;

[0047] In the formula, L2 is the distance from the first gear to the center of the gear, L3 is the outer ring diameter of the first gear, and L4 is the inner ring diameter of the first gear;

[0048] The cross-section of the gear at the oil leak port satisfies the following formula:

[0049] ;

[0050] In the formula, L1 is the length of the oil leak, in mm; L5 is the depth of the oil leak, in mm; and Q is the oil supply rate, in L / min.

[0051] The angle between the location of the vent and the vertical direction is within ±60°, and the cross-sectional area is not less than 1 / 2 of the cross-sectional area of ​​the oil leak.

[0052] In summary, this application has the following advantages:

[0053] The bearing fastening structure combining the outer ring flange fixation and the aluminum alloy bushing avoids the maintenance and scrapping of the casing, reducing repair costs. At the same time, it can effectively suppress the fretting wear of the outer ring of the bearing, improve the bearing positioning accuracy, and avoid premature failure of the bearing and gear.

[0054] The bearing bushing and the casing housing form an annular oil passage. An oil supply hole is provided on the bushing to lubricate and cool the bearing. Compared with external nozzle oil spraying, the structure is more compact, simple, and reliable; it is especially suitable for use under high ambient temperature conditions.

[0055] The bearing cavity is equipped with an oil drain port and a ventilation port to facilitate oil return and prevent oil churning. At the same time, a design method for the structural dimensions of the oil drain port is proposed, which is efficient, reliable and practical.

[0056] 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. A fastening structure for an aero-engine accessory housing bearing, characterized in that, It includes a casing (2), a gear shaft (7), a first bearing (3), a second bearing (8), a first bushing (1), and a second bushing (5); The casing (2) has two sets and is respectively located at both ends of the gear shaft (7). One end of the gear shaft (7) is connected to one set of casing (2) through a first bearing (3), and the other end is connected to the casing (2) through a second bearing (8). The first bushing (1) is disposed between the first bearing (3) and the casing (2), and the second bushing (5) is disposed between the second bearing (8) and the casing (2); The outer rings of the first bearing (3) and the second bearing (8) are provided with flanges, which are connected to the casing (2) by threaded fasteners (4). The first bushing (1) and the second bushing (5) are both made of aluminum alloy.

2. The aircraft engine accessory housing bearing fastening structure as described in claim 1, characterized in that, A first annular oil passage (6) is provided between the first bushing (1) and the casing (2), and a second annular oil passage (9) is provided between the second bushing (5) and the casing (2). Lubricating oil for cooling can be introduced into the first annular oil passage (6) and the second annular oil passage (9). The first bushing (1) and the second bushing (5) are provided with oil supply holes that communicate with the first annular oil passage (6) or the second annular oil passage (9).

3. The aircraft engine accessory housing bearing fastening structure as described in claim 2, characterized in that, The casing (2) is provided with an oil drain port and a ventilation port. The oil drain port is located in the lower part of the bearing cavity of the first bearing (3) or the second bearing (8), and the ventilation port is located in the upper part of the bearing cavity of the first bearing (3) or the second bearing (8).

4. The aircraft engine accessory housing bearing fastening structure as described in claim 3, characterized in that, The angle between the middle position of the oil leak and the vertical direction is: L2=(L3+L4) / 2; In the formula, L2 is the distance from the first gear to the center of the gear, L3 is the outer ring diameter of the first gear, and L4 is the inner ring diameter of the first gear; The cross-section of the gear at the oil leak port satisfies the following formula: ； In the formula, L1 is the length of the oil leak, L5 is the depth of the oil leak, and Q is the oil supply.

5. The aircraft engine accessory housing bearing fastening structure as described in claim 1, characterized in that, The angle between the location of the vent and the vertical direction is within ±60°, and the cross-sectional area is not less than 1 / 2 of the cross-sectional area of ​​the oil leak.

6. The aircraft engine accessory housing bearing fastening structure as described in claim 1, characterized in that, The first bushing (1) and the first bearing (3), and the second bushing (5) and the outer ring of the second bearing (8) are all clearance fits; the first bushing (1) and the second bushing (5) are interference fits with the casing (2).

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