Compact aircraft engine accessory gearbox

Abstract

This application discloses a compact aircraft engine accessory gearbox, including a housing with internal oil flow channels and fuel flow channels. The housing also includes an oil pump mounting section, a fuel pump mounting section, an oil filter mounting section, a fuel filter mounting section, and a heat exchanger mounting section. Specifically, the oil pump has a sealing end face, with the oil pump suction port, oil pump supply port, and at least one return port coplanarly disposed on the sealing end face, and the sealing end face forming an end face seal with the oil pump by a common fastener; the fuel pump mounting section mounts the fuel pump by a radial seal; and the oil filter mounting section, fuel filter mounting section, and heat exchanger mounting section are also included. More specifically, the oil filter mounting section, heat exchanger mounting section, and oil pump mounting section are arranged adjacent to each other, such that the oil flow channel connecting the three is minimized; the fuel filter mounting section and fuel pump mounting section are arranged adjacent to each other, such that the fuel flow channel connecting the two is minimized.

Description

Technical Field

[0001] This invention relates to the field of aircraft engine accessory gearbox design, and more particularly to a compact aircraft engine accessory gearbox. Background Technology

[0002] The accessory gearbox of an aero-engine is a critical component that provides mounting interfaces and power transmission for major accessories such as the oil pump, fuel pump, regulator, starter generator, oil filter, and valves. Its shape and structure directly affect the overall external layout of the engine, significantly influencing its weight, size, and reliability. In related technologies, accessory gearboxes typically employ a multi-body or split design, with accessories such as oil filters, magnetic chip sensors, and heat exchangers distributed in different parts such as the pump housing and pipelines. This layout, to a certain extent, enables the installation and driving of various accessories.

[0003] However, the aforementioned existing technical solutions have significant drawbacks. First, due to the dispersed arrangement of accessories and pipelines, the overall structure of the gearbox lacks compactness, occupies a large space, and is not conducive to the optimal utilization of the engine's external space. Second, the dispersed design leads to complex internal pipeline layout, a large number of parts, and a risk of leakage at each connection point, resulting in a decrease in overall reliability. Furthermore, the dispersed interface of each accessory results in poor overall coordination, requiring the connection of multiple external pipelines during assembly, making maintenance operations inconvenient and affecting the engine's assembly efficiency and the convenience of daily maintenance.

[0004] Therefore, optimizing the layout and structure of accessory gearboxes, improving their compactness and integration, reducing the number of parts, and improving assembly and maintenance convenience have become urgent technical problems to be solved in this field. Summary of the Invention

[0005] In view of this, to solve at least one technical problem in related technologies and other aspects, this application proposes a compact aircraft engine accessory gearbox, including a housing with built-in lubricating oil flow channels and fuel flow channels. The housing also has a lubricating oil pump mounting section, a fuel pump mounting section, a lubricating oil filter mounting section, a fuel filter mounting section, and a heat exchanger mounting section. Specifically, the lubricating oil pump mounting section is suitable for mounting a lubricating oil pump and has a sealing end face. The lubricating oil pump's oil intake port, oil supply port, and at least one return port are coplanarly disposed on the sealing end face, and the sealing end face forms an end face seal with the lubricating oil pump through shared fasteners. The fuel pump mounting section is suitable for mounting a fuel pump by means of radial sealing. The lubricating oil filter mounting section, the heat exchanger mounting section, and the lubricating oil pump mounting section are arranged adjacently, such that the lubricating oil flow channel connecting the lubricating oil filter mounting section, the heat exchanger mounting section, and the lubricating oil pump mounting section is minimized. The fuel filter mounting section and the fuel pump mounting section are arranged adjacently, such that the fuel flow channel connecting the fuel filter mounting section and the fuel pump mounting section is minimized.

[0006] According to an embodiment of this application, the housing also includes a generator mounting portion, which is disposed at the far end of the oil filter mounting portion and the fuel filter mounting portion to avoid spatial interference with the oil flow channel and the fuel flow channel.

[0007] According to an embodiment of this application, the lubricating oil flow channel includes a supply sub-channel and a return sub-channel. One end of the supply sub-channel is connected to the lubricating oil pump supply port, and the other end is sequentially connected to the heat exchanger lubricating oil inlet of the heat exchanger mounting section, the heat exchanger lubricating oil outlet, and the lubricating oil filter interface of the lubricating oil filter mounting section. After flowing from the lubricating oil filter mounting section, it is connected to multiple sub-supply ports. One end of the return sub-channel is connected to at least one return oil pipe interface, and the other end is connected to the return oil port of the lubricating oil pump mounting section. After pressurization, it is connected to the main lubricating oil return outlet.

[0008] According to an embodiment of this application, the return oil sub-channel further includes at least one magnetic chip sensor, which is configured to be connected to the return oil pipe interface and the return oil port.

[0009] According to an embodiment of this application, one end of the fuel flow channel is connected to the outlet of the fuel pump in the fuel pump mounting section, and the other end is sequentially connected to the fuel inlet and fuel outlet of the heat exchanger mounting section, enters the fuel filter mounting section from the fuel filter interface, and is connected to the fuel supply interface.

[0010] According to an embodiment of this application, the housing further includes an oil filter bypass valve interface and / or a fuel filter bypass valve interface. The oil filter bypass valve interface is configured to be connected in parallel with the oil filter mounting portion in the oil supply sub-channel of the oil flow channel, suitable for bypassing oil flow when the oil filter is clogged; the fuel filter bypass valve interface is configured to be connected in parallel with the fuel filter mounting portion in the fuel flow channel, suitable for bypassing fuel flow when the fuel filter is clogged.

[0011] According to embodiments of this application, the housing further includes an oil filter clogging alarm interface and / or a fuel filter clogging alarm interface. The oil filter clogging alarm interface is configured to connect the oil flow channels on both the upstream and downstream sides of the oil filter mounting section, and is suitable for detecting the clogging status of the oil filter; the fuel filter clogging alarm interface is configured to connect the fuel flow channels on both the upstream and downstream sides of the fuel filter mounting section, and is suitable for detecting the clogging status of the fuel filter.

[0012] According to an embodiment of this application, the housing further includes a fuel-cooling lubricating oil inlet. One end of the fuel-cooling lubricating oil inlet is connected to the oil supply sub-channel, and the other end is adapted to connect to the bearing cooling inlet of the fuel pump mounted on the fuel pump mounting section, for supplying cooling lubricating oil to the bearing of the fuel pump.

[0013] According to an embodiment of this application, the housing also includes a ventilation pipe interface for connecting to an engine ventilation system to balance the internal pressure of the gearbox.

[0014] According to an embodiment of this application, the aforementioned compact aircraft engine accessory gearbox further includes a cover plate. The cover plate has integrally formed cross ribs on its inner side.

[0015] According to an embodiment of this application, in this compact aero-engine accessory gearbox, the housing incorporates internal lubricating oil and fuel flow channels, eliminating the need for external piping and related connectors, thus reducing the number of parts. The lubricating oil pump mounting section has a sealing end face, with the oil inlet, supply outlet, and return outlet coplanarly located on this end face. A shared fastener forms an end face seal, allowing multiple ports to be compressed simultaneously, resulting in a large sealing surface and uniform stress distribution, lowering the risk of leakage, and eliminating the need for connectors for multiple individual interfaces. The fuel pump mounting section employs a radial sealing method, adaptable to the installation characteristics of the fuel pump. The lubricating oil filter mounting section, heat exchanger mounting section, and lubricating oil pump mounting section are arranged adjacently, resulting in a shorter lubricating oil flow channel between them, which helps reduce flow resistance and pressure loss; the adjacent arrangement of the fuel filter mounting section and fuel pump mounting section also shortens the fuel flow channel. This adjacent layout further shortens the flow path of the medium within the housing, helping to maintain pump outlet pressure, while making the overall housing structure more compact and occupying less space. Attached Figure Description

[0016] Figure 1 This is a perspective view of the housing of the compact aircraft engine accessory gearbox in the embodiments of this application from a first-view perspective;

[0017] Figure 2 This is a perspective view of the housing of the compact aircraft engine accessory gearbox in the embodiments of this application from a second perspective.

[0018] Figure 3 This is a perspective view of the housing of the compact aircraft engine accessory gearbox in the embodiments of this application from a third-person perspective;

[0019] Figure 4 This is a perspective view of the cover plate of the compact aircraft engine accessory gearbox in the embodiments of this application from a first-view perspective.

[0020] [Meaning of Labels in the Attached Image]

[0021] 101-Sealed end face, 102-Lubricating oil pump drive interface, 103-Lubricating oil pump suction port, 104-First return oil port, 105-Second return oil port, 106-Third return oil port, 107-Lubricating oil pump supply port, 108-First return oil pipe interface, 109-Second return oil pipe interface, 110-Heat exchanger lubricating oil inlet, 111-Heat exchanger lubricating oil outlet, 112-Lubricating oil filter interface, 113-Lubricating oil filter blockage alarm interface, 114-Lubricating oil filter bypass valve interface, 115-Fuel conditioning and cooling lubricating oil interface, 116-Ventilation pipe interface, 117-First sub-supply port, 118-Second sub-supply port, 119-Third sub-supply port, 120-Lubricating oil return main Outlet, 121-Lubricating oil extraction port, 122-Gearbox return port, 123-Gearbox vent, 124-Gear lubrication supply port, 125-First magnetic chip sensor, 126-Second magnetic chip sensor, 127-Gearbox exhaust port, 201-Fuel pump port, 202-Fuel pump outlet, 203-Fuel inlet, 204-Fuel outlet, 205-Fuel filter port, 206-Fuel filter blockage alarm port, 207-Fuel filter bypass valve port, 208-Fuel supply port, 301-Heat exchanger mounting positioning hole, 302-Gear plug, 303-Motor port, 304-Gearbox fixing bolt hole, 305-Cross rib. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0023] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0025] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0026] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] In the description of this application, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0028] Throughout the accompanying drawings, identical elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted where they may cause confusion in understanding this application. Furthermore, the shapes, dimensions, and positional relationships of the components in the drawings do not reflect their actual size, scale, or actual positional relationships. Additionally, any reference symbols placed within parentheses in this application should not be construed as limiting the scope of this application.

[0029] Similarly, to simplify this application and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of this application, various features of this application are sometimes grouped together into a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0032] In the process of developing this application, it was discovered that the related technologies for aero-engine accessory gearboxes mostly adopt a split design, with accessories and pipelines scattered in different parts such as the pump housing and pipelines. This results in a less compact structure, a large number of parts, and inconvenient assembly and maintenance. Further analysis revealed that the root cause of the above problems lies in two aspects: First, the connection methods between each accessory and the gearbox are not designed to differentiate them according to the characteristics of the accessories. The lubricating oil pump has a large number of interfaces, but they are connected in a decentralized manner, which limits the sealing reliability. Second, the spatial layout of the accessories lacks overall planning. The relative positions of key components such as pumps, filters, and heat exchangers are far apart, resulting in long and winding external or internal pipelines, which not only occupy space but also increase the risk of leakage and assembly complexity.

[0033] Based on this, this application proposes to arrange the multiple oil ports of the lubricating oil pump on the same plane and achieve end face sealing by using common fasteners. At the same time, according to the functional characteristics of the accessories, the fuel pump adopts radial sealing. The lubricating oil pump, lubricating oil filter, and heat exchanger are arranged adjacent to each other according to the principle of the shortest medium flow path, and the fuel pump and fuel filter are arranged adjacent to each other, so as to make the overall structure more compact, the internal flow channel shorter, and the number of parts fewer.

[0034] This application discloses a compact aircraft engine accessory gearbox, including a housing with built-in oil and fuel flow channels. The housing also includes an oil pump mounting section, a fuel pump mounting section, an oil filter mounting section, a fuel filter mounting section, and a heat exchanger mounting section. Specifically, the oil pump mounting section is suitable for mounting an oil pump and has a sealing end face 101. The oil pump's oil intake port 103, oil supply port 107, and at least one return port are coplanarly disposed on the sealing end face 101. The sealing end face 101 forms an end face seal with the oil pump through shared fasteners. The fuel pump mounting section is suitable for mounting a fuel pump using a radial sealing method. The oil filter mounting section, heat exchanger mounting section, and oil pump mounting section are arranged adjacently to minimize the oil flow channel connecting them. The fuel filter mounting section and fuel pump mounting section are arranged adjacently to minimize the fuel flow channel connecting them.

[0035] According to an embodiment of this application, in this compact aero-engine accessory gearbox, the housing incorporates internal lubricating oil and fuel flow channels, eliminating the need for external piping and related connectors, thus reducing the number of parts. The lubricating oil pump mounting section has a sealing end face 101, and the lubricating oil pump suction port 103, lubricating oil pump supply port 107, and return port are coplanarly disposed on this end face. A common fastener forms an end face seal, allowing multiple ports to be compressed simultaneously, resulting in a large sealing surface and uniform stress distribution, lowering the risk of leakage, and eliminating the need for connectors required for multiple individual interfaces. The fuel pump mounting section employs a radial sealing method, adaptable to the installation characteristics of the fuel pump. The lubricating oil filter mounting section, heat exchanger mounting section, and lubricating oil pump mounting section are arranged adjacently, resulting in a shorter lubricating oil flow channel length between them, which helps reduce flow resistance and pressure loss; the adjacent arrangement of the fuel filter mounting section and fuel pump mounting section also shortens the fuel flow channel. This adjacent layout further shortens the flow path of the medium within the housing, helping to maintain pump outlet pressure, while making the overall housing structure more compact and occupying less space.

[0036] In some specific embodiments, the sliding pump mounting part also includes a lubricating oil pump drive interface 102, which is suitable for transmitting the transmission torque inside the gearbox to the lubricating oil pump to drive the lubricating oil pump to work, so that the lubricating oil pump's functions of pumping, supplying and returning oil can be realized.

[0037] In some specific embodiments, the oil return port of the lubricating oil pump includes a first oil return port 104, a second oil return port 105, and a third oil return port 106.

[0038] In some specific embodiments, the fuel pump mounting part further includes a fuel pump interface 201, which is suitable for cooperating with the housing or mounting base of the fuel pump to achieve the connection between the fuel pump and the housing and the docking of the fuel flow passage through a radial sealing method.

[0039] In some specific embodiments, the heat exchanger mounting part also includes a heat exchanger mounting positioning hole 301, which is suitable for alignment with the mating structure on the heat exchanger to achieve precise positioning of the heat exchanger on the shell and ensure accurate docking of the lubricating oil inlet and outlet with the internal flow channel of the shell.

[0040] According to an embodiment of this application, the housing also includes a generator mounting portion, which is disposed at the far end of the oil filter mounting portion and the fuel filter mounting portion to avoid spatial interference with the oil flow channel and the fuel flow channel.

[0041] According to the embodiments of this application, since the lubricating oil pump, heat exchanger, fuel pump, and other accessories, along with their associated lubricating oil and fuel flow channels, are already concentrated near the lubricating oil filter mounting section and the fuel filter mounting section, the internal flow channels in this area are relatively dense. By placing the generator mounting section at the far end of the two mounting sections, i.e., away from this dense area, it can effectively prevent the generator interface 303 from spatially overlapping or interfering with the existing lubricating oil and fuel flow channels within the housing. This ensures reliable installation and transmission of the generator without affecting the integrity of the original flow channel layout, eliminating the need for detours in the flow channel design to avoid the generator, and helping to maintain the shortest path for the flow channels and the compactness of the housing structure.

[0042] According to an embodiment of this application, the lubricating oil flow channel includes a supply sub-flow channel and a return sub-flow channel. One end of the supply sub-flow channel is connected to the lubricating oil pump supply port 107, and the other end is sequentially connected to the heat exchanger lubricating oil inlet 110, the heat exchanger lubricating oil outlet 111, and the lubricating oil filter interface 112 of the lubricating oil filter installation section. After flowing from the lubricating oil filter installation section, it is connected to multiple sub-supply ports. One end of the return sub-flow channel is connected to at least one return oil pipe interface, and the other end is connected to the return oil port of the lubricating oil pump installation section. After pressurization, it is connected to the main lubricating oil return outlet 120.

[0043] According to an embodiment of this application, the oil supply sub-channel starts from the oil supply port 107 of the lubricating oil pump, passes sequentially through the lubricating oil inlet 110 of the heat exchanger, the lubricating oil outlet 111 of the heat exchanger, and then reaches the lubricating oil filter interface 112, before being branched to multiple sub-supply ports. This sequence ensures that the lubricating oil, after being pumped out, first enters the heat exchanger for cooling, then enters the lubricating oil filter for filtration, and only then is it distributed to each lubrication point, ensuring that the supplied lubricating oil is at a suitable temperature and clean. The oil supply sub-channel flows at the lubricating oil filter installation section, realizing simultaneous oil supply to multiple lubrication points. The oil return sub-channel collects the lubricated lubricating oil from at least one return oil pipe interface, leads it back to the return oil port of the lubricating oil pump installation section, and after being pressurized by the return oil pump inside the lubricating oil pump, it is discharged from the lubricating oil return main outlet 120. The pressurization process helps overcome the flow resistance in the return oil pipeline, ensuring smooth oil return. The oil supply and return sub-channels have a clear division of labor, forming a complete lubricating oil circulation path. All of them are integrated inside the housing, so the lubricating oil can be sent back to the pump body for recirculation without the need for an external return oil pipeline.

[0044] In some specific embodiments, the lubricating oil flows from the lubricating oil intake port 121 through an internal pipeline to the lubricating oil pump intake port 103, where it enters the lubricating oil pump for pressurization. The pressurized lubricating oil then enters the lubricating oil pump supply port 107.

[0045] In some specific embodiments, the return oil pipe interface of the return oil sub-channel includes a first return oil pipe interface 108 and a second return oil pipe interface 109.

[0046] In some specific embodiments, the sub-fuel supply port includes a first sub-fuel supply port 117, a second sub-fuel supply port 118, and a third sub-fuel supply port 119.

[0047] In some more specific embodiments, the oil supply sub-path starts from the oil pump supply port 107, passes through the internal pipeline of the gearbox to the heat exchanger oil inlet 110, and after passing through the heat exchanger, enters the internal pipeline of the gearbox from the heat exchanger oil outlet 111. It then enters the oil filter through the internal pipeline. The oil filter bypass is equipped with an oil filter blockage alarm and is connected to the front and rear of the oil filter through internal pipelines. The oil filter bypass is also equipped with an oil filter bypass valve, which is connected to the front and rear of the oil filter through internal pipelines. After passing through the oil filter, the oil is supplied to various lubrication points through the internal pipelines from the first sub-oil supply port 117, the second sub-oil supply port 118, the third sub-oil supply port 119, the fuel-cooling oil interface 115, and the gear lubrication oil supply port 124.

[0048] According to an embodiment of this application, the return oil sub-channel further includes at least one magnetic chip sensor, which is configured to be connected to the return oil pipe interface and the return oil port.

[0049] According to an embodiment of this application, after lubricating each lubrication point, the lubricating oil enters the return oil sub-channel through the return oil pipe interface. Along the path leading to the return oil port of the lubricating oil pump, it sequentially flows past the magnetic chip sensor to capture metal shavings carried in the lubricating oil. Since the return oil carries wear information from all lubrication points, the detection results are more representative. Therefore, the magnetic chip sensor is arranged in the return oil sub-channel. Furthermore, placing it before the return oil port and before the return oil pump pressurization avoids the impact of changes in lubricating oil flow rate or pressure after pressurization on the detection accuracy, thus improving the accuracy and reliability of monitoring.

[0050] In some specific embodiments, the wear debris in the return oil may originate from the wear of the gear meshing surface or the rolling elements of the bearing. Therefore, by detecting the content and morphology of wear debris in the lubricating oil, the wear condition of the transmission components inside the gearbox can be determined.

[0051] In some specific embodiments, the magnetic chip sensor includes a first magnetic chip sensor 125 and a second magnetic chip sensor 126.

[0052] In some more specific embodiments, the return oil is connected via pipelines to the first return oil port 108 and the second return oil port, which are then connected via internal pipelines to the first return oil port 104 and the second return oil port 105, respectively. A first magnetic chip sensor 125 and a second magnetic chip sensor 126 are installed on these two internal pipelines. The two return oil paths merge into one after passing through the return oil pump, return to the gearbox via the third return oil port 106, and then, after passing through internal pipelines, connect to an external pipeline at the lubricating oil return outlet 120 to return to the oil tank.

[0053] In some specific embodiments, the housing also includes a gearbox oil return port 122, which serves as a supplementary inlet for the oil return sub-channel. It is used to receive oil return from other lubrication points or chambers outside the gearbox, allowing it to flow into the internal oil return path and then to the lubricating oil pump oil return port.

[0054] According to an embodiment of this application, one end of the fuel flow channel is connected to the fuel pump outlet 202 of the fuel pump mounting section, and the other end is sequentially connected to the fuel inlet 203 and fuel outlet 204 of the heat exchanger mounting section, enters the fuel filter mounting section from the fuel filter interface 205, and is connected to the fuel supply interface 208.

[0055] According to an embodiment of this application, the fuel processing flow within the housing is as follows: after being output from the low-pressure fuel pump, the fuel first enters the heat exchanger to exchange heat with the lubricating oil, and is preheated to improve combustion efficiency; then it enters the fuel filter for filtration to remove impurities; finally, it is supplied to the downstream high-pressure fuel pump or fuel regulator through the fuel supply interface 208. Integrating all the aforementioned processing steps into the fuel flow channel within the housing eliminates the need for external piping connections, reducing leakage points and the number of parts. Furthermore, although the fuel flow channel and the lubricating oil supply sub-channel form a cross-heat exchange relationship at the heat exchanger, the fuel flow channel itself remains independent, avoiding the risk of fuel and lubricating oil mixing. This compact series path design results in a shorter fuel flow path within the housing, which is beneficial for maintaining fuel pressure.

[0056] According to an embodiment of this application, the housing further includes an oil filter bypass valve interface and / or a fuel filter bypass valve interface 207. The oil filter bypass valve interface 114 is configured to be connected in parallel with the oil filter mounting portion in the oil supply sub-channel of the oil flow channel, suitable for bypassing oil flow when the oil filter is clogged; the fuel filter bypass valve interface 207 is configured to be connected in parallel with the fuel filter mounting portion in the fuel flow channel, suitable for bypassing fuel flow when the fuel filter is clogged.

[0057] According to an embodiment of this application, during normal operation, lubricating oil flows through the lubricating oil filter in the lubricating oil filter mounting section for filtration. When the lubricating oil filter becomes clogged due to impurities, the pressure difference in the oil supply sub-channel triggers the bypass valve to open, allowing lubricating oil to flow directly from the bypass valve interface around the filter element to the downstream, thereby ensuring the continuity of lubricating oil supply and preventing gear or bearing burnout due to lubrication interruption caused by filter element blockage. Similarly, the fuel filter bypass valve interface 207 is connected in parallel with the fuel filter mounting section in the fuel flow channel. When the fuel filter is clogged, fuel continues to be supplied downstream through the bypass valve interface, bypassing the fuel filter, ensuring uninterrupted engine fuel supply. The aforementioned bypass valve interface serves as a safety protection device, improving the operational reliability of the accessory gearbox in the event of filter element blockage. Furthermore, the parallel structure is integrated inside the housing, eliminating the need for external bypass pipelines and making the structure more compact.

[0058] According to embodiments of this application, the housing further includes an oil filter clogging alarm interface 113 and / or a fuel filter clogging alarm interface 206. The oil filter clogging alarm interface 113 is configured to connect the oil flow channels on both the upstream and downstream sides of the oil filter mounting portion, and is suitable for detecting the clogging status of the oil filter; the fuel filter clogging alarm interface 206 is configured to connect the fuel flow channels on both the upstream and downstream sides of the fuel filter mounting portion, and is suitable for detecting the clogging status of the fuel filter.

[0059] According to an embodiment of this application, during normal operation, the pressure difference between the upstream and downstream sides of the lubricating oil filter is small when the lubricating oil flows through it; as the lubricating oil filter gradually becomes clogged, the pressure difference across the filter element increases. The alarm interface connects the upstream and downstream lubricating oil channels to the same blockage alarm (e.g., a differential pressure indicator). When the pressure difference exceeds a set threshold, the alarm issues a blockage signal, prompting maintenance personnel to replace the filter element. Similarly, the fuel filter blockage alarm interface 206 connects the fuel channels on both the upstream and downstream sides of the fuel filter mounting section to detect the blockage status of the fuel filter. The design of the aforementioned alarm interface allows for real-time monitoring of the blockage status, avoiding frequent triggering of the bypass valve due to filter element blockage (the bypass valve only opens when completely blocked and does not pass through the filter), and preventing the filter element from being severely blocked but still being used without an alarm. This structure integrates the detection function inside the housing, eliminating the need for additional detection points on external pipelines, simplifying the layout and improving detection reliability.

[0060] According to an embodiment of this application, the housing further includes a fuel-cooling lubricating oil inlet 115. One end of the fuel-cooling lubricating oil inlet 115 is connected to the oil supply sub-channel, and the other end is adapted to connect to the bearing cooling inlet of the fuel pump mounted on the fuel pump mounting section, for supplying cooling lubricating oil to the bearing of the fuel pump.

[0061] According to an embodiment of this application, the fuel pump bearings generate heat during high-speed operation, requiring cooling to ensure normal operating life. The oil supply sub-channel carries clean lubricating oil that has been cooled by a heat exchanger and filtered by an oil filter; this oil has a low temperature and high cleanliness, making it suitable as a cooling medium. By drawing a lubricating oil path from the oil supply sub-channel and supplying it to the fuel pump bearing cooling inlet via the fuel conditioning cooling lubricating oil interface 115, the fuel pump bearing can be lubricated and cooled. This design eliminates the need for a separate external cooling pipeline or independent cooling oil source for the fuel pump bearing, fully utilizing the existing lubricating oil system of the accessory gearbox and reducing additional pipelines and interfaces. Furthermore, since the lubricating oil typically flows back to the return oil system or is separately recycled after cooling the fuel pump bearing, this interface demonstrates an expansion of the lubricating oil system's function, extending from merely lubricating internal gearbox components to lubricating and cooling external accessories, further improving system integration.

[0062] According to an embodiment of this application, the housing also includes a ventilation pipe interface 116 for connecting to an engine ventilation system to balance the internal pressure of the gearbox.

[0063] According to embodiments of this application, during operation, the internal pressure of the gearbox may rise or fall due to factors such as gear meshing and oil churning, changes in lubricating oil temperature, and pressure fluctuations within the sealed chamber. Excessive pressure may cause lubricating oil leakage from the seals; insufficient pressure (negative pressure) may affect the smoothness of oil return or even draw in external impurities. Connecting the internal chamber of the gearbox to the engine ventilation system via the ventilation pipe interface 116 allows for a dynamic balance between the pressure inside the gearbox and the ventilation system pressure, maintaining it within a suitable operating range. This interface prevents the gearbox from becoming a closed pressure differential chamber, improving the reliability of the sealing system and helping to maintain normal oil flow in the return oil channel. It eliminates the need for an independent pressure regulating device, resulting in a simple and effective structure.

[0064] In some specific embodiments, the housing also includes a gearbox vent 123, which is connected to a ventilation pipe interface 116, together forming a gas passage between the internal chamber of the gearbox and the engine ventilation system, for achieving internal pressure balance and oil-gas separation.

[0065] In some specific embodiments, the compact aero-engine accessory gearbox arranges the interfaces of the lubricating oil pump, fuel pump, regulator, starter generator, oil filter, valve, etc. on the same gearbox body according to the principle of optimal space utilization, thus achieving an ultra-compact structure.

[0066] In some specific embodiments, the housing also includes a gearbox exhaust port 127, which is connected to the fuel flow passage and is used to vent the gas in the fuel line before engine start or after maintenance to prevent gas resistance from affecting fuel supply stability.

[0067] According to an embodiment of this application, the aforementioned compact aircraft engine accessory gearbox further includes a cover plate. The cover plate has an integrally formed cross rib 305 on its inner side.

[0068] According to embodiments of this application, the cover plate, as a sealing component of the gearbox, needs to withstand certain internal pressure and loads transmitted by accessories mounted on it. Providing cross ribs 305 on the inner side of the cover plate is equivalent to adding a reinforcing structure to the cover plate body. The grid-like or cross-shaped arrangement of the cross ribs 305 can significantly improve the bending stiffness and structural strength of the cover plate with a small increase in material usage. Since the cross ribs 305 are integrally formed with the cover plate (e.g., through casting or additive manufacturing), there is no connection interface between them, avoiding the stress concentration and connection failure risks that may arise from welding or riveting. The cover plate with cross ribs 305 allows for a thinner cover plate while maintaining high stiffness, thereby reducing the cover plate's weight and correspondingly reducing the overall size of the gearbox in the cover plate thickness direction (i.e., axial direction). The cross ribs 305 also enable the cover plate to evenly distribute loads when subjected to stress in different areas, improving the cover plate's resistance to deformation and helping to maintain the sealing reliability between the cover plate and the housing.

[0069] In some specific embodiments, there are no pipe connection interfaces between the housing and the cover, reducing the risk of sealing problems.

[0070] In some specific embodiments, the housing also includes gearbox fixing bolt holes 304, which are suitable for inserting fasteners to fix the entire accessory gearbox to the aircraft engine casing, ensuring the gearbox's positional stability and reliable connection during operation.

[0071] In some specific embodiments, the housing also includes a gear plug 302, which is suitable for sealing process holes on the housing for machining or assembling gears, preventing lubricating oil from leaking from the holes, and maintaining the internal sealing of the gearbox.

[0072] In some more specific embodiments, the arrangement of accessories can be optimized and adjusted according to the engine structure in different application scenarios. For example, the positions of pump accessories can be interchanged, and the internal flow channels can be adjusted and redundantly designed to adapt to aero engines with different power levels.

[0073] It should be noted that the described embodiments are merely some, not all, of the embodiments described in this application. Other embodiments obtained by those skilled in the art based on the embodiments described in this application without inventive effort are all within the scope of protection of this application.

[0074] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A compact aircraft engine accessory gearbox, comprising: A housing having an oil flow channel and a fuel flow channel, the housing comprising: The lubricating oil pump mounting part is suitable for mounting a lubricating oil pump and has a sealing end face. The lubricating oil pump suction port, the lubricating oil pump supply port and at least one return port of the lubricating oil pump are coplanarly disposed on the sealing end face. The sealing end face forms an end face seal with the lubricating oil pump through the common fastener. A fuel pump mounting part, suitable for mounting a fuel pump by means of a radial seal; and, Oil filter mounting section, fuel filter mounting section, and heat exchanger mounting section; among which... The lubricating oil filter mounting part, the heat exchanger mounting part, and the lubricating oil pump mounting part are arranged adjacent to each other, so that the lubricating oil flow path connecting the lubricating oil filter mounting part, the heat exchanger mounting part, and the lubricating oil pump mounting part is the shortest. The fuel filter mounting part and the fuel pump mounting part are arranged adjacent to each other, so that the fuel flow path connecting the fuel filter mounting part and the fuel pump mounting part is the shortest.

2. The compact aircraft engine accessory gearbox according to claim 1, wherein, The housing also includes a generator mounting section, located at the far end of the oil filter mounting section and the fuel filter mounting section, to avoid spatial interference with the oil flow channel and the fuel flow channel.

3. The compact aircraft engine accessory gearbox according to claim 1, wherein, The lubricating oil flow channel includes an oil supply sub-flow channel and an oil return sub-flow channel; One end of the oil supply sub-channel is connected to the oil supply port of the lubricating oil pump, and the other end is connected in sequence to the lubricating oil inlet of the heat exchanger installation part, the lubricating oil outlet of the heat exchanger installation part, and the lubricating oil filter interface of the lubricating oil filter installation part, and then flows from the lubricating oil filter installation part to multiple sub-oil supply ports respectively. One end of the oil return sub-channel is connected to at least one oil return pipe interface, and the other end is connected to the oil return port of the lubricating oil pump mounting part. After being pressurized, it is connected to the main lubricating oil return outlet.

4. The compact aircraft engine accessory gearbox according to claim 3, wherein, The return oil sub-channel also includes at least one magnetic chip sensor, which is configured to connect to the return oil pipe interface and the return oil port.

5. The compact aircraft engine accessory gearbox according to claim 1, wherein, One end of the fuel flow channel is connected to the fuel pump outlet of the fuel pump mounting section, and the other end is sequentially connected to the fuel inlet and fuel outlet of the heat exchanger mounting section, enters the fuel filter mounting section from the fuel filter interface, and is connected to the fuel supply interface.

6. The compact aircraft engine accessory gearbox according to claim 1 or 5, wherein, The housing also includes: The oil filter bypass valve interface is configured to be connected in parallel with the oil filter mounting part in the oil supply sub-channel of the oil flow channel, and is suitable for bypassing the oil flow when the oil filter is blocked. The fuel filter bypass valve interface is configured to be connected in parallel with the fuel filter mounting part in the fuel flow passage, and is suitable for bypassing fuel flow when the fuel filter is clogged.

7. The compact aircraft engine accessory gearbox according to claim 3 or 5, wherein, The housing also includes: The lubricating oil filter blockage alarm interface is configured to connect the lubricating oil flow channels on the upstream and downstream sides of the lubricating oil filter mounting part, and is suitable for detecting the blockage status of the lubricating oil filter; The fuel filter clogging alarm interface is configured to connect the fuel flow channels on the upstream and downstream sides of the fuel filter mounting section, and is suitable for detecting the clogging status of the fuel filter.

8. The compact aircraft engine accessory gearbox according to claim 3, wherein, The housing also includes: A fuel-cooling lubricating oil inlet is provided, one end of which is connected to the oil supply sub-channel, and the other end is adapted to be connected to the bearing cooling inlet of the fuel pump installed in the fuel pump mounting part, for supplying cooling lubricating oil to the bearing of the fuel pump.

9. The compact aircraft engine accessory gearbox according to claim 1, wherein, The housing also includes: A ventilation duct interface is used to connect to the engine ventilation system to balance the internal pressure of the gearbox.

10. The compact aircraft engine accessory gearbox according to claim 1, further comprising: The cover plate has an integrally formed cross rib on its inner side.

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