Fireproof accessory transmission case and aircraft engine

Abstract

The invention discloses a fireproof accessory transmission casing and an aircraft engine, wherein the fireproof accessory transmission casing comprises a first casing body and a second casing body provided with an accessory mounting position for mounting engine accessories, the accessory mounting position is provided with a reversing sealing structure, the reversing sealing structure comprises a plurality of fitting sealing surfaces connected in sequence and arranged at an angle, and is used to clamp the engine accessories together through the plurality of fitting sealing surfaces for sealing; the accessory mounting position comprises a lubricating oil pump mounting position arranged on the first casing body, and a fuel pump mounting position and an oil filter unit mounting position arranged on the second casing body, the fuel pump mounting position and the oil filter unit mounting position are connected through a fuel high-pressure pipeline and a fuel low-pressure pipeline, the lubricating oil pump mounting position and the oil filter unit mounting position are connected through a lubricating oil pipeline, and the lubricating oil pipeline, the fuel low-pressure pipeline and the fuel high-pressure pipeline are arranged in sequence along a flame direction away from the expected engine fire. The invention can greatly improve the sealing effect and fireproof performance.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft engines, and in particular to a fireproof accessory transmission casing and an aircraft engine using the fireproof accessory transmission casing. Background Art

[0002] The main function of the aircraft engine accessory transmission case is to contain the gears for accessory transmission and provide an installation platform for the engine and aircraft accessories. On the premise of achieving the function, in order to improve the power-to-weight ratio of the aircraft engine, the accessory transmission case needs to be reduced in weight. Considering that the accessory transmission case is located at the cold end of the engine and the temperature is low when the engine is working normally, it is usually cast with aluminum alloy or magnesium alloy. In the accessory transmission case cavity, there is a lubricating oil mist condition for lubricating gears, bearings, splines, etc. Once a fire occurs in the aircraft, leakage from the accessory transmission case may cause the fire to spread, resulting in an uncontrollable fire, affecting flight safety. In addition, the accessory transmission case is installed with engine electrical system accessories, and abnormal electrical components may also cause positive and negative charges to accumulate and become a source of ignition, igniting the leaked lubricating oil from the accessory transmission case. Therefore, the accessory transmission case needs a fireproof design, and it needs to be tested and verified to show that it complies with the provisions of the Civil Aviation Administration of China's airworthiness regulations "Aircraft Engine Airworthiness Regulations" (CCAR-33-R2), that is, every external pipeline, joint and other component that retains or transports flammable liquids during normal engine operation must be confirmed to be fire-resistant or fireproof. Other components mentioned in the regulations include the accessory transmission gearbox. As the accessory transmission case is the direct impact part of the accessory transmission gearbox fire, its fire resistance is particularly critical.

[0003] The existing aircraft engine accessory transmission casing is still designed only according to functional requirements, and no specific protective measures are set to ensure its fire safety. According to airworthiness requirements, accessory transmission casings that are judged to be fire-resistant must withstand a fire test at 2000℉ (1100℃) for at least 15 minutes. For civil aviation engines, the 15-minute fire test is divided into two stages. The first stage is 5 minutes, simulating the normal operation of the engine; the second stage is 10 minutes, simulating the continuous rotation of the engine after shutdown. The accessory transmission casing made of aluminum alloy or magnesium alloy as raw materials has a melting point far lower than the fire test verification temperature, and it is difficult to pass the fire test assessment without using protection or heat dissipation methods.

[0004] In the fire test of the existing accessory transmission case, the lubricating oil mist sprayed into the accessory transmission case cavity flows and evaporates under two different engine states to provide heat dissipation conditions for the accessory transmission case. This method is applicable to fixed-wing aircraft engines such as turbofans and turboprops, but not to turboshaft engines used in rotorcraft, because in the 10-minute test of the second stage of the fire test, it is necessary to simulate the lubricating oil supply in the continuous rotation state after the engine is shut down, and the rotorcraft continues to rotate at an extremely low speed after the engine is shut down. The engine lubricating oil pump cannot provide enough lubricating oil flow to provide heat dissipation for the accessory transmission case. The lubricating oil mist remaining in the accessory transmission case cavity alone is not enough to support it to pass the 10-minute test of the second stage. Summary of the invention

[0005] The invention provides a fireproof accessory transmission casing to solve the technical problem that the accessory transmission casing in the prior art has poor fireproof performance.

[0006] According to one aspect of the present invention, there is provided a fireproof accessory transmission casing, comprising a first casing body and a second casing body, wherein the outer edge of the first casing body and the outer edge of the second casing body are connected by fasteners, and the first casing body and the second casing body are provided with accessory mounting positions for mounting engine accessories, and the accessory mounting positions are provided with a reversing sealing structure, the reversing sealing structure comprises a plurality of sequentially connected fitting sealing surfaces, and two adjacent fitting sealing surfaces are arranged at an angle, and the reversing sealing structure is used to engage the engine accessories together through the plurality of fitting sealing surfaces for sealing;

[0007] The accessory mounting positions include an oil pump mounting position arranged on the first casing body and a fuel pump mounting position and an oil filter unit mounting position arranged on the second casing body. The fuel pump mounting position and the oil filter unit mounting position are connected by a fuel high-pressure pipeline and a fuel low-pressure pipeline. The oil pump mounting position and the oil filter unit mounting position are connected by a lubricating oil pipeline. The lubricating oil pipeline, the fuel low-pressure pipeline and the fuel high-pressure pipeline are arranged in sequence along the width direction of the first casing body toward the direction of the flame away from the expected engine fire situation.

[0008] Furthermore, a lubricating oil pipeline interface connected to the lubricating oil pipeline is provided at the bottom of the outer wall of the second casing body, and the opening direction of the lubricating oil pipeline interface has an angle relative to the flame direction expected in the engine fire situation. The lubricating oil pipeline interface is used to communicate with the engine bearing cavity for oil return.

[0009] Furthermore, a nozzle mounting hole is provided on the lubricating oil pipeline, and the nozzle mounting hole is arranged at the bend of the lubricating oil pipeline and is used to segment the lubricating oil pipeline;

[0010] A nozzle is installed on the nozzle installation hole.

[0011] Furthermore, the accessory mounting position also includes a sensor mounting position, a starter mounting position, and a radiator mounting position arranged on the first casing body, and a generator mounting position and a fuel regulator mounting position arranged on the second casing body.

[0012] The surfaces of the sensor mounting position, the starter mounting position, the generator mounting position and the fuel regulator mounting position are provided with an insulating film layer, and the portion of the insulating film layer for contacting with the engine accessories is formed with a conductive layer through oxidation treatment.

[0013] Furthermore, a conductive component is provided between the conductive layer and the engine accessory, and the conductive component includes a bolt for fastening the engine accessory to the engine mounting position, and a conductive screw sleeve and a conductive washer sleeved outside the bolt.

[0014] The sensor mounting position, the starter mounting position, the generator mounting position and the fuel regulator mounting position are provided with connection holes, the conductive layer is arranged in the connection holes, and the conductive screw sleeve is passed through and fixed in the connection holes and abuts against the conductive layer.

[0015] Furthermore, radial sealing rings are provided on the generator mounting position, sensor mounting position, lubricating oil pump mounting position, fuel pump mounting position and oil filter unit mounting position. The radial sealing rings are used to radially abut the corresponding engine accessories. The radial sealing rings are provided on one of the fitting sealing surfaces in the reversing sealing structure. The reversing sealing structure is also provided with at least one fitting sealing surface on the outside of the fitting sealing surface.

[0016] Furthermore, the design tolerance of the shaft hole fitting clearance between the accessory mounting position and the engine accessory is set to 0.02mm~0.1mm.

[0017] Furthermore, the sensor installation position is provided with a chamfer at the connection end of two adjacent sealing surfaces, and the chamfer is used to enclose with the corner end of the sensor to form a space for installing the chamfered sealing ring to enhance the sealing.

[0018] Furthermore, the outer walls of the first casing body and the second casing body are provided with elastic fireproof coatings.

[0019] According to another aspect of the present invention, there is also provided an aircraft engine using the fireproof accessory transmission case.

[0020] The present invention has the following beneficial effects:

[0021] The fireproof accessory transmission casing of the present invention arranges the lubricating oil pipeline at one end of the casing body close to the flame expected in the engine fire so that the high-temperature parts of the casing body can be dissipated in time, and the low-pressure fuel pipeline and the high-pressure fuel pipeline with a lower boiling point and easier evaporation are arranged in sequence above the lubricating oil pipeline to avoid the high pressure generated by the evaporation of the oil in the low-pressure fuel pipeline and the high-pressure fuel pipeline causing the casing body to rupture, thereby optimizing the heat dissipation layout of the pipelines inside the casing body by arranging the lubricating oil pipeline, the low-pressure fuel pipeline and the high-pressure fuel pipeline in sequence in a direction away from the flame expected in the engine fire, thereby greatly improving the heat dissipation efficiency. The fireproof accessory transmission casing is provided with a reversing sealing structure on the accessory mounting position. Compared with the method of only using radial rubber rings for radial sealing in the prior art, the reversing sealing structure engages the engine accessory through a plurality of fitting sealing surfaces connected in sequence and arranged at an angle to seal the gap between the accessory mounting position and the engine accessory. This can not only prevent the oil inside the casing body from leaking from the gap due to high-temperature failure of the radial sealing ring, thereby greatly enhancing the sealing effect, but also has a certain protective effect on the radial sealing ring, preventing the flame outside the casing body from impacting the radial sealing ring through the gap, preventing the fire from increasing and spreading, thereby greatly improving the fireproof performance.

[0022] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 The structure of the fireproof accessory transmission case of the preferred embodiment of the present invention is shown in FIG. Figure 1 ;

[0025] Figure 2 The structure of the fireproof accessory transmission case of the preferred embodiment of the present invention is shown in FIG. Figure 2 ;

[0026] Figure 3 is a cross-sectional schematic diagram of a second casing body of a preferred embodiment of the present invention;

[0027] Figure 4 is a cross-sectional schematic diagram of a first casing body of a preferred embodiment of the present invention;

[0028] Figure 5 It is a cross-sectional schematic diagram of a reversing stage of a reversing sealing structure of a preferred embodiment of the present invention;

[0029] Figure 6It is a cross-sectional schematic diagram of a double reversing reversing seal structure of a preferred embodiment of the present invention;

[0030] Figure 7 It is a cross-sectional schematic diagram of a triple reversing reversing sealing structure of a preferred embodiment of the present invention;

[0031] Figure 8 is a schematic diagram of the installation position of the sensor in the preferred embodiment of the present invention;

[0032] Fig. 9 It is a cross-sectional schematic diagram of a conductive component according to a preferred embodiment of the present invention.

[0033] Legend:

[0034] 10. First casing; 11. Lubricating oil pump installation position; 12. Sensor installation position; 13. Starter installation position; 14. Radiator installation position; 20. Second casing; 21. Fuel pump installation position; 22. Oil filter unit installation position; 23. Generator installation position; 24. Fuel regulator installation position; 30. Reversing seal structure; 31. Fitting sealing surface; 40. Lubricating oil pipeline; 41. Lubricating oil pipeline interface; 42. Nozzle installation hole; 50. Low-pressure fuel pipeline; 60. High-pressure fuel pipeline; 70. Insulating film layer; 80. Conductive component; 81. Bolt; 82. Conductive screw sleeve; 83. Conductive gasket; 90. Radial sealing ring; 100. Chamfered sealing ring; 110. Pipe joint. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0036] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the fireproof accessory transmission case of this embodiment includes a first case body 10 and a second case body 20. The first case body 10 and the second case body 20 are arranged in a split type and fixedly connected by fasteners on the outer edges. The first case body 10 and the second case body 20 are provided with a plurality of accessory installation positions for correspondingly installing engine accessories. Figure 5 , Figure 6 and Figure 7As shown, a reversing seal structure 30 is provided on the accessory installation position, and the reversing seal structure 30 includes a plurality of sequentially connected fitting seal surfaces 31, and two adjacent fitting seal surfaces 31 are arranged at an angle, and are used to seal the engine accessories together through the plurality of fitting seal surfaces 31. Specifically, the accessory installation position is provided with a radial sealing ring 90, and the radial sealing ring 90 abuts against the corresponding engine accessories in the radial direction and is arranged on one of the fitting seal surfaces 31 of the reversing seal structure 30. The reversing seal structure 30 is also provided with at least one fitting seal surface 31 on the outer side of the radial sealing ring 90, so that the accessory installation position forms a plurality of sealing surfaces in different directions through the engagement of the reversing seal structure 30 with the engine accessories for multiple reversing seals, which greatly enhances the sealing effect. The number of fitting seal surfaces 31 of the reversing seal structure 30 and the angle between the two adjacent fitting seal surfaces 31 are set according to the oil pressure of the engine accessories. Preferably, the angle between the two adjacent fitting seal surfaces is 90°. Preferably, the number of fitting seal surfaces is set to 1 to 4. Compared with the sealing method in the prior art, the reversing sealing structure 30 seals the gap between the accessory mounting position and the engine accessory through multiple reversals, which can not only prevent the oil inside the casing from leaking from the gap due to the failure of the radial sealing ring 90 due to high temperature, thereby enhancing the sealing effect, but also has a certain protective effect on the radial sealing ring 90 between the accessory mounting position and the engine accessory, avoiding the flame outside the casing from passing through the gap to impact the radial sealing ring 90 and causing failure, preventing the fire from increasing and spreading, thereby greatly improving the fire protection performance.

[0037] like Figure 1 , Figure 2 and Figure 3 As shown, the accessory installation position includes a lubricating oil pump installation position 11 arranged on the first casing body 10, a fuel pump installation position 21 and an oil filter unit installation position 22 arranged on the second casing body 20, a fuel high-pressure pipeline 60, a fuel low-pressure pipeline 50 and a lubricating oil pipeline 40 are arranged between the first casing body 10 and the second casing body 20, a first cavity and a second cavity are arranged in the oil filter unit installation position 22, a lubricating oil cavity is arranged in the lubricating oil pump installation position 11, the lubricating oil pump is installed on the lubricating oil pump installation position 11 and communicates through the lubricating oil cavity, and the lubricating oil pipeline 40 is communicated with the first cavity and the lubricating oil cavity. A fuel high-pressure cavity and a fuel low-pressure cavity are arranged in the fuel pump installation position 21, the fuel high-pressure pump and the fuel low-pressure pump are installed on the fuel pump installation position 21 and communicate through the fuel high-pressure cavity and the fuel low-pressure cavity respectively, one end of the fuel high-pressure pipeline 60 and the fuel low-pressure pipeline 50 are both communicated with the second cavity, and the other end is respectively communicated with the fuel high-pressure cavity and the fuel low-pressure cavity.

[0038] like Figure 3As shown, the lubricating oil pipeline 40, the low-pressure fuel pipeline 50 and the high-pressure fuel pipeline 60 are arranged in parallel along the length direction of the first casing body 10, and are arranged in sequence at intervals along the direction of the flame away from the expected engine fire. The lubricating oil pipeline 40 is used to cool and lubricate the interior of the fireproof accessory transmission casing, and its pressure is the lowest. The lubricating oil pipeline 40 is arranged at the end of the casing body close to the expected engine fire flame, so that it can dissipate heat to the high-temperature parts of the casing body in time. The pressures of the low-pressure fuel pipeline 50 and the high-pressure fuel pipeline 60 increase in sequence and have low boiling points. The low-pressure fuel pipeline 50 and the high-pressure fuel pipeline 60 are arranged in sequence above the lubricating oil pipeline 40 to avoid the high pressure generated by the evaporation of the oil in the low-pressure fuel pipeline 50 and the high-pressure fuel pipeline 60 in a high-temperature environment, which may cause the casing body to rupture. Therefore, by adjusting the positions of the lubricating oil pipeline 40, the low-pressure fuel pipeline 50 and the high-pressure fuel pipeline 60, the heat dissipation layout of the internal pipelines of the casing body is optimized, and the heat dissipation efficiency is greatly improved. Preferably, there is no cross-overlap between the lubricating oil pipeline 40, the low-pressure fuel pipeline 50 and the high-pressure fuel pipeline 60, which is conducive to casting and ensures the strength and stability of the pipeline. Preferably, the high-pressure fuel pipeline 60, the low-pressure fuel pipeline 50 and the lubricating oil pipeline 40 are integrally cast with the first casing body 10 and the second casing body 20, which can eliminate process holes and reduce the use of connecting guide sleeves, thereby reducing the total weight of the fireproof accessory transmission casing; preferably, the high-pressure fuel pipeline 60, the low-pressure fuel pipeline 50 and the lubricating oil pipeline 40 are integrally cast, with fewer pipeline connection positions, effectively preventing oil leakage at the pipeline connection, and ensuring fireproof performance.

[0039] like Figure 2 , Figure 3 As shown, the lubricating oil pipeline 40 is integrated and arranged at one end of the fireproof accessory transmission casing close to the flame expected in the engine fire, so as to dissipate heat inside the fireproof accessory transmission casing. The bottom of the outer wall of the second casing body 20 is provided with a lubricating oil pipeline interface 41 connected to the lubricating oil pipeline 40, which is used to connect with the engine bearing cavity for oil return and lubrication. The lubricating oil pipeline interface 41 is arranged at the bottom, so that the lubricating oil can be more easily returned to the lubricating oil tank during the circulation process under the action of gravity, thereby improving the recovery efficiency of the lubricating oil and reducing waste and leakage risks. The opening direction of the lubricating oil pipeline interface 41 has an angle with respect to the flame direction expected in the engine fire, so as to avoid the lubricating oil pipeline interface 41 being directly impacted by the flame expected in the engine fire, thereby ensuring fireproof performance. Preferably, the lubricating oil pipeline interface 41 is vertically arranged on the side of the second casing body 20.

[0040] like Figure 4As shown, the lubricating oil pipeline 40 is arranged between the first casing body 10 and the second casing body 20 and is integrally cast. A nozzle mounting hole 42 is opened on the lubricating oil pipeline 40 to segment the long curved lubricating oil pipeline 40, so that the lubricating oil pipeline 40 forms a straight and short structure, reduces the demand for process holes on the first casing body 10 and / or the second casing body 20, avoids the use of welding to seal the process holes resulting in low strength of the joint, ensures the structural stability of the fireproof accessory transmission casing, reduces the risk of leakage, improves the sealing performance, reduces the pressure loss of the lubricating oil pipeline 40, and ensures smooth flow of oil. The nozzle mounting hole 42 is arranged at the bend of the lubricating oil pipeline 40 with poor bonding strength, which can reduce the casting difficulty of the lubricating oil pipeline 40, improve the structural strength of the bend of the lubricating oil pipeline 40 and ensure the uniform wall thickness of the bend of the lubricating oil pipeline 40, avoid the breakage of the lubricating oil pipeline 40 at the turning point to cause oil leakage, ensure the smooth flow of oil in the lubricating oil pipeline 40, so as to timely dissipate heat inside the fireproof accessory transmission casing. At the same time, it is not necessary to arrange process holes on the first casing body 10 and / or the second casing body 20 to position and support the internal lubricating oil pipeline 40, and avoid the process holes blocked by welding due to the low strength of the bonding part with the first casing body 10 and / or the second casing body 20, resulting in poor structural stability of the fireproof accessory transmission casing. A nozzle is installed on the nozzle installation hole 42 to block the nozzle installation hole 42, effectively preventing oil leakage from the lubricating oil pipeline 40, and at the same time, the oil in the lubricating oil pipeline 40 is sprayed to the inside of the fireproof accessory transmission casing through the nozzle to lubricate the components. Preferably, one end of the nozzle is fixed to the inner wall of the first casing body 10 and / or the second casing body 20 to position the lubricating oil pipeline 40 and ensure the stability of the lubricating oil pipeline 40.

[0041] like Figures 1 to 4 as well as Fig. 9 As shown, the accessory mounting position also includes a sensor mounting position 12, a starter mounting position 13 arranged on the first casing body 10, and a generator mounting position 23 and a fuel regulator mounting position 24 arranged on the second casing body 20. The sensor mounting position 12, the starter mounting position 13, the generator mounting position 23 and the fuel regulator mounting position 24 are used to install electrical accessories of the engine. The surfaces of the first casing body 10 and the second casing body 20 are provided with an insulating film layer 70, and the insulating film layer 70 is formed by anodizing hot surface treatment. On the one hand, the insulating film layer 70 can form an electrical barrier on the surface of the first casing body 10 and the second casing body 20 to prevent current from leaking to the surface, thereby ensuring the safe operation of the fireproof accessory transmission casing. On the other hand, it can resist the erosion of media such as fuel and lubricating oil, enhance corrosion resistance and durability, and improve service life.

[0042] like Fig. 9As shown, the insulating film layer 70 on the accessory installation position for contacting the electrical accessories is subjected to chemical conductive oxidation treatment, so that a conductive layer is formed locally on the insulating film layer 70 at the accessory installation position, and a conductive component 80 is arranged between the conductive layer and the engine accessories, and the conductive component 80 includes a bolt 81 and a conductive screw sleeve 82 and a conductive washer 83 sleeved on the outside of the bolt 81. A connection hole is arranged on the accessory installation position corresponding to the electrical accessories, and the conductive layer is arranged in the connection hole. The conductive screw sleeve 82 is fixed in the connection hole and abuts the conductive layer. Thus, the conductive component 80 can make the conductive screw sleeve 82, the conductive washer 83 and the bolt 81 contact with the conductive layer to form a conductive channel, realize the electrical connection between the electrical accessories and the accessory installation position, and facilitate the discharge of the charge generated by the electrical accessories, avoid the accumulation of positive and negative charges on the outer surface of the fireproof accessory transmission casing to become a fire source, and improve the fireproof performance. Optionally, electrical test points can be set at specific locations of the conductive layer to ensure conductivity by detecting resistance values, thereby facilitating fault detection and diagnosis. Preferably, the sensor mounting position 12, the starter mounting position 13, the generator mounting position and the fuel regulator mounting position 24 are provided with connection holes and a conductive layer.

[0043] like Figure 5 , Figure 6 and Figure 7 As shown, a radial sealing ring 90 is provided between the generator mounting position 23, the sensor mounting position 12, the lubricating oil pump mounting position 11, the fuel pump mounting position 21 and the oil filter unit mounting position 22 and the engine accessories. The radial sealing ring 90 is used to radially abut the corresponding engine accessories. The radial sealing ring 90 is provided on one of the fitting sealing surfaces in the reversing sealing structure. The reversing sealing structure 30 is also provided with at least one fitting sealing surface 31 on the outer side of the radial sealing ring 90.

[0044] Specifically, the reversing seal structure 30 is arranged on the accessory installation position, and includes a plurality of sequentially connected fitting seal surfaces 31, and two adjacent fitting seal surfaces 31 are arranged at an angle. The reversing seal structure 30 engages with the corresponding engine accessories through the plurality of fitting seal surfaces 31 to seal. Thus, the accessory installation position forms a plurality of sealing surfaces in different directions through the engagement of the reversing seal structure 30 with the engine accessories to perform multiple reversing seals, which greatly enhances the sealing effect. The setting of the reversing seal structure 30 can not only seal the gap between the accessory installation position and the engine accessories, but also prevent the oil inside the casing from leaking from the gap due to the failure of the radial sealing ring 90 due to high temperature, and can also have a certain protective effect on the radial sealing ring 90, so as to prevent the flame outside the casing from passing through the gap to impact the radial sealing ring 90, and prevent the fire from increasing and spreading, thereby greatly improving the fireproof performance.

[0045] The number of the fitting sealing surfaces 31 of the reversing sealing structure 30 and the angle between two adjacent fitting sealing surfaces 31 are set according to the oil pressure of the engine accessories. Preferably, the angle between two adjacent fitting sealing surfaces is 90°. Preferably, the number of fitting sealing surfaces is set to 1-4. Preferably, the sealing oil pressure between the generator mounting position 23 and the generator and between the sensor mounting position 12 and the sensor is relatively small, so the reversing sealing structure 30 there is only one fitting sealing surface 31 arranged outside the radial sealing ring 90, and the sealing and fire protection requirements can be met through one reversal. The sealing oil pressure between the lubricating oil pump mounting position 11 and the lubricating oil pump is relatively large, and the reversing sealing structure 30 there is two fitting sealing surfaces 31 arranged outside the radial sealing ring 90, and the sealing and fire protection requirements can be met through double reversal. The fuel regulator installation position 24 and the fuel regulator, the fuel pump installation position 21 and the fuel pump, and the oil filter unit installation position 22 and the oil filter unit accessories are all connected through the pipe joint 110. The reversing seal structure 30 therein is provided with three fitting sealing surfaces 31 on the outside of the radial sealing ring 90, and the sealing and fireproofing requirements are met through triple reversal. Optionally, there is an oil circuit connecting pipe structure connected to the lubricating oil tank at the installation position of the fireproof accessory transmission casing and the engine, and the sealing oil pressure is small, so the reversing seal structure 30 is provided therein to ensure its fireproof safety. Optionally, the reversing seal structure 30 therein adopts single reversal.

[0046] like Figure 5 , Figure 6 and Figure 7 As shown, in this embodiment, the sealing oil pressure between the generator mounting position 23 and the generator and between the sensor mounting position 12 and the sensor is relatively small, so the reversing sealing structure 30 there is only provided with one fitting sealing surface 31, and the sealing and fire protection requirements can be met through one reversal.

[0047] In the present embodiment, a radial sealing ring 90 is provided between the accessory mounting position and the engine accessory. The radial sealing ring 90 is embedded in the engine accessory and abuts against the inner wall of the accessory mounting position to perform radial sealing, so that an axial hole fitting clearance is formed between the accessory mounting position and the engine accessory to ensure the installation of the radial sealing ring 90. In the present embodiment, the design tolerance of the axial hole fitting clearance is reduced to be controlled within 0.02mm~0.1mm. This design tolerance can not only ensure the normal installation and use of the radial sealing ring 90, but also improve the fireproof performance and prevent the radial sealing ring 90 from failing due to high-temperature carbonization, resulting in oil leakage from the axial hole fitting clearance. At the same time, this design tolerance can also protect the radial sealing ring 90 and prevent external flames from impacting the radial sealing ring 90 through the axial hole fitting clearance. Figure 5As shown, in one embodiment of the present invention, the fuel regulator installation position 24 is connected to the fuel regulator through a pipe joint 110, and radial sealing rings 90 are provided at both ends of the pipe joint 110, which are used to radially seal the fuel regulator installation position 24 and the fuel regulator, respectively, so that an axial hole matching clearance is formed between the pipe joint 110 and the fuel regulator installation position 24 and the fuel regulator, and the axial hole matching clearance is set to 0.02mm~0.1mm. Optionally, the axial hole matching clearance between the accessory installation position and the engine accessory can also range from 0.03mm~0.13mm.

[0048] like Figure 8 As shown, the sensor installation position 12 is arranged on the first casing body 10, and is used to install the sensor to monitor the state of the fireproof accessory transmission casing in real time. A radial sealing ring 90 for radial sealing is arranged between the sensor and the sensor installation position 12, and the shaft hole matching clearance between the sensor and the sensor installation position 12 is controlled to be 0.02mm~0.1mm. However, since the first casing body 10 is cast with aluminum alloy, and the sensor is made of stainless steel with a thermal expansion coefficient lower than that of the aluminum alloy, the shaft hole matching clearance between the sensor and the sensor installation position 12 will increase under high temperature environment, and the structure of the sensor is difficult to change. Therefore, a chamfer is arranged on the inner wall of the connecting end of the sensor installation position 12, so that the chamfer is arranged on the side of the radial sealing ring 90 away from the first casing body 10 and the corner end of the sensor to form a space for installing the chamfered sealing ring 100, so that the volume of the chamfered sealing ring 100 is compressed by setting the chamfer, and the sealing performance is enhanced by adding a chamfered sealing ring 100 outside the radial sealing ring 90. This method does not affect the maintenance of the sensor, does not need to change the original structure of the sensor, and has low development cost.

[0049] Preferably, the outer walls of the first casing body 10 and the second casing body 20 are provided with an elastic fireproof coating to prevent the fireproof accessory transmission casing from being ignited from the outside, thereby further improving the fireproof performance of the fireproof accessory transmission casing.

[0050] In addition, the present invention also discloses an aircraft engine, which comprises the above-mentioned fireproof accessory transmission casing.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fireproof accessory transmission case, characterized in that: The invention comprises a first casing body (10) and a second casing body (20), wherein the outer edge of the first casing body (10) and the outer edge of the second casing body (20) are connected by fasteners, and the first casing body (10) and the second casing body (20) are provided with accessory mounting positions for mounting engine accessories, and the accessory mounting positions are provided with a reversing sealing structure (30), and the reversing sealing structure (30) comprises a plurality of sequentially connected abutting sealing surfaces (31), and two adjacent abutting sealing surfaces (31) are arranged at an angle, and the reversing sealing structure (30) is used to engage the engine accessories together through the plurality of abutting sealing surfaces (31) to perform sealing; The accessory mounting position comprises a lubricating oil pump mounting position (11) arranged on the first casing body (10) and a fuel pump mounting position (21) and an oil filter unit mounting position (22) arranged on the second casing body (20); the fuel pump mounting position (21) and the oil filter unit mounting position (22) are connected via a fuel high-pressure pipeline (60) and a fuel low-pressure pipeline (50); the lubricating oil pump mounting position (11) and the oil filter unit mounting position (22) are connected via a lubricating oil pipeline (40); the lubricating oil pipeline (40), the fuel low-pressure pipeline (50) and the fuel high-pressure pipeline (60) are arranged in sequence along a flame direction away from an expected engine fire condition.

2. The fireproof accessory transmission case according to claim 1, characterized in that: The bottom of the outer wall of the second casing (20) is provided with a lubricating oil pipeline interface (41) which is in communication with the lubricating oil pipeline (40); the opening direction of the lubricating oil pipeline interface (41) has an angle with respect to the flame direction expected in the engine fire situation; the lubricating oil pipeline interface (41) is used to communicate with the engine bearing cavity for returning the lubricating oil.

3. The fireproof accessory transmission case according to claim 1, characterized in that: The lubricating oil pipeline (40) is provided with a nozzle mounting hole (42), and the nozzle mounting hole (42) is arranged at a bend of the lubricating oil pipeline (40) and is used to divide the lubricating oil pipeline (40) into sections; A nozzle is installed on the nozzle installation hole (42).

4. The fireproof accessory transmission case according to claim 1, characterized in that: The accessory mounting positions also include a sensor mounting position (12), a starter mounting position (13), and a radiator mounting position (14) arranged on the first casing body (10), and a generator mounting position (23) and a fuel regulator mounting position (24) arranged on the second casing body (20). The surfaces of the sensor mounting position (12), the starter mounting position (13), the generator mounting position (23) and the fuel regulator mounting position (24) are provided with an insulating film layer (70), and a conductive layer is formed on the portion of the insulating film layer (70) that is used for contacting the engine accessories through oxidation treatment.

5. The fireproof accessory transmission case according to claim 4, characterized in that: A conductive component (80) is provided between the conductive layer and the engine accessory, the conductive component (80) comprising a bolt (81) for fastening the engine accessory to the engine mounting position, and a conductive screw sleeve (82) and a conductive washer (83) sleeved outside the bolt (81). The sensor mounting position (12), the starter mounting position (13), the generator mounting position (23) and the fuel regulator mounting position (24) are all provided with connection holes, the conductive layer is arranged in the connection hole, and the conductive screw sleeve (82) is passed through and fixed in the connection hole and abuts against the conductive layer.

6. The fireproof accessory transmission case according to claim 4, characterized in that: The generator mounting position (23), the sensor mounting position (12), the lubricating oil pump mounting position (11), the fuel pump mounting position (21) and the oil filter unit mounting position (22) are all provided with radial sealing rings (90), the radial sealing rings (90) are used to radially abut against corresponding engine accessories, the radial sealing rings (90) are arranged on one of the abutting sealing surfaces (31) in the reversing sealing structure (30), and the reversing sealing structure (30) is also provided with a abutting sealing surface (31) on the outer side of the radial sealing ring.

7. The fireproof accessory transmission case according to claim 1, characterized in that: The design tolerance of the shaft hole matching clearance between the accessory mounting position and the engine accessory is set to 0.02mm~0.1mm.

8. The fireproof accessory transmission case according to claim 4, characterized in that: The sensor installation position (12) is provided with a chamfer at the connection end of two adjacent fitting sealing surfaces (31), and the chamfer is used to enclose with the corner end of the sensor to form a space for installing the chamfered sealing ring (100) to enhance the seal.

9. The fireproof accessory transmission case according to claim 1, characterized in that: The outer walls of the first casing body (10) and the second casing body (20) are provided with elastic fireproof coatings.

10. An aircraft engine, characterized in that: A fireproof accessory transmission case comprising the fireproof accessory transmission case according to any one of claims 1 to 9.

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