Turbine engine and associated aircraft

Abstract

The invention relates to an accessory drive gearbox (25), which comprises: - a casing; - a transmission shaft (32; 32a); and - a transmission system (40) comprising: a pinion (45) fixedly mounted on the transmission shaft and comprising external teeth (45a), a ring gear (46) suitable for being connected to an accessory drive shaft (27; 27a), and comprising internal teeth (48), engaging with the external teeth (45a), such that a rotation of the pinion (45) with respect to the casing (28) rotates the ring gear (46) with respect to the casing, a nozzle (55) able to be rotated relative to the casing and configured, when it is rotating, to expel lubricating oil, and an oil deflector (56) configured to guide the lubricating oil expelled by the nozzle (55) to the internal teeth (48) of the ring gear (46).

Description

[0001] DESCRIPTION

[0002] Turbomachine and associated aircraft

[0003] TECHNICAL FIELD

[0004] The present invention relates to an accessory drive housing for an aircraft propulsion system, such as for example a gas turbine engine or an aircraft turboprop.

[0005] STATE OF THE ART

[0006] An aircraft propulsion system, for example, comprises, from upstream to downstream in the direction of gas flow, a fan section, a compressor section which may include a low-pressure compressor and a high-pressure compressor, a combustion chamber, and a turbine section which may include a high-pressure turbine and a low-pressure turbine. The high-pressure compressor is driven in rotation by the high-pressure turbine via a high-pressure shaft. The fan, and where applicable the low-pressure compressor, are driven in rotation by the low-pressure turbine via a low-pressure shaft, and possibly also via a gear reducer. The high-pressure compressor, the combustion chamber, and the high-pressure turbine together form a high-pressure unit. The fan, the low-pressure compressor, and the low-pressure turbine together form a low-pressure unit.

[0007] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by different countries. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0008] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes these factors into account in all phases of design and development to obtain less energy-intensive and more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving aircraft energy efficiency.

[0009] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0010] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0011] Thus, in order to improve the propulsive efficiency of the propulsion system and reduce its specific fuel consumption, it has been found that, to obtain the same thrust, it is more advantageous to accelerate a large quantity of air less than to accelerate a smaller quantity of air more strongly. With this in mind, a new generation of propulsion systems, known as Open Fan, has been proposed, in which the fan blades are unshod and have variable pitch, as do the fan stator blades, generally called outlet guide vanes (OGVs).Open fan propulsion systems, designed to improve propulsion efficiency, offer a high bypass ratio (BPR, the ratio between the secondary airflow and primary airflow) by increasing the fan diameter and, consequently, the external dimensions of the propulsion system (and therefore its mass and drag). This makes integrating the propulsion system more difficult, in addition to increasing its mass and specific fuel consumption. The gas flow rate in the high-pressure section and the size of the high-pressure section are also reduced, and the low-pressure turbine occupies a forward position. Another aspect of the open fan propulsion system is the electric hybridization of the engine.The Open Fan propulsion system is expected to bring a 20% reduction in carbon dioxide emissions compared to the latest generation of propulsion systems known as LEAP, which itself achieved a 15 to 20% reduction in these emissions compared to the previous generation called CFM56.

[0012] Aircraft propulsion systems, whether open-fan or not, generally include an accessory gearbox, commonly referred to as an "AGB" for "Accessory Gear Box." The accessory gearbox is a component that includes a transmission system whose primary function is, during normal propulsion system operation, to draw some of the mechanical energy produced by the propulsion system to drive various auxiliary accessories necessary for the operation of the propulsion system or the aircraft, such as hydraulic pumps, oil pumps, fuel pumps, electric generators for generating electrical power, etc. The accessory gearbox may also be connected to a starter motor to mechanically start the propulsion system during startup.Typically, particularly in a ducted fan-driven gas turbine engine such as the CFM56 or LEAP, the accessory drive unit is located in the fan section, specifically around the fan housing. Some gas turbine engines, known as "open fan" engines, have an unducted fan. In these engines, the accessory drive unit is located in the compressor section, an area where space is limited.

[0013] Therefore, the compactness of the accessory drive unit becomes a crucial factor in order to optimize its integration and that of the accessories it drives. Optimal integration of the accessory drive unit is one that does not alter the ideal aerodynamic lines defined by the gas turbine engine manufacturer, since such a modification negatively impacts the gas turbine engine's performance and therefore its fuel consumption.

[0014] The compactness of the accessory drive gearbox is even more critical when the propulsion system is a hybrid system incorporating electric generators with rotational speeds significantly higher than conventional electric generators—typically 75% higher than the speeds of the fastest current accessory drives, and typically 600% higher than those of the slowest current accessories. These higher rotational speeds normally necessitate the addition of extra gear cascades to the accessory drive gearbox's gear train, thus reducing its overall compactness.

[0015] EXPOSED

[0016] One aim of this application is to propose a set of accessory drive housings including a compact gear configuration while allowing efficient gear lubrication.

[0017] The invention relates to an accessory drive housing comprising:

[0018] - a casing comprising a first wall and a second wall opposite the first wall;

[0019] - a transmission shaft mounted to rotate relative to the housing, the transmission shaft extending transversely between the first wall and the second wall, and comprising one end;

[0020] - a transmission system arranged at the end of the transmission shaft and configured to transmit power from the transmission shaft to an accessory drive shaft, the transmission system comprising: a pinion fixedly mounted on the transmission shaft, the pinion having external teeth, a ring gear suitable for being connected to the accessory drive shaft, the ring gear having internal teeth, meshing with the external teeth of the pinion, so that a rotation of the pinion relative to the housing causes a rotation of the ring gear relative to the housing, a nozzle suitable for being driven into rotation relative to the housing and configured, when rotating, to expel lubricating oil, and an oil deflector configured to guide the lubricating oil expelled by the nozzle to the internal teeth of the ring gear.

[0021] Advantageously, the oil deflector is fixedly mounted on the crown, so that a rotation of the crown relative to the crankcase causes a rotation of the oil deflector relative to the crankcase.

[0022] Advantageously, the crown includes a cylindrical central part designed to be connected to the drive shaft of the accessory, the oil deflector being mounted on the cylindrical central part.

[0023] Preferably, the oil deflector includes:

[0024] - a central portion having a first guiding surface extending perpendicularly to an axis of rotation of the crown, and

[0025] - a peripheral portion surrounding the central portion, the peripheral portion having a second frustoconical guiding surface extending from the first guiding surface towards the internal teeth of the crown, so that the lubricating oil expelled by the oil jet is guided successively by the first guiding surface and then by the second guiding surface or only by the second guiding surface towards the internal teeth of the crown.

[0026] Advantageously, the oil deflector has a free edge located opposite the internal teeth of the crown, the peripheral portion extending to the free edge of the oil deflector.

[0027] Advantageously, the free edge has a diameter smaller than the crown head diameter, the crown head diameter being defined as the diameter of a circle passing through the apexes of the internal teeth.

[0028] Preferably, the free edge of the oil deflector is located less than 50 millimeters from the internal teeth of the crown.

[0029] In one embodiment, the peripheral portion comprises a plurality of guide teeth, the guide teeth being separated by an inter-tooth space between two successive guide teeth for the passage of oil between the two successive guide teeth, and being oriented so that each tooth of the internal teeth of the crown is located opposite an inter-tooth space of the peripheral portion.

[0030] Advantageously, the oil deflector comprises a tubular portion extending around the cylindrical central part of the crown and fixed to the cylindrical central part of the crown. Advantageously, the nozzle comprises a plurality of oil expulsion orifices extending radially about an axis of rotation of the crown.

[0031] The invention also relates to an accessory drive housing assembly, comprising a drive housing as defined above and an accessory comprising a drive shaft, the accessory drive shaft being connected to the ring gear of the transmission system.

[0032] Advantageously, the accessory is an oil pump, the oil pump being suitable for supplying the nozzle with lubricating oil.

[0033] Advantageously, the accessory is a first accessory, the accessory drive shaft is a first drive shaft and the end of the transmission shaft is a first end, the housing assembly comprising a second accessory comprising a second drive shaft, the transmission shaft comprising a second end opposite to the first end, the second end of the transmission shaft being configured to drive in rotation the second drive shaft of the second accessory.

[0034] The invention also relates to a gas turbine engine comprising a compressor section including a compressor rotor, a turbine section including a turbine rotor and a shaft connecting the turbine rotor to the compressor rotor so that in operation a rotation of the turbine rotor causes a rotation of the compressor rotor, an accessory drive housing assembly as defined above, a power transfer shaft and a radial drive shaft connecting the shaft to the accessory drive housing via the power transfer shaft to drive the accessory drive housing's transmission shaft in rotation.

[0035] The invention also relates to an aircraft comprising a fuselage and at least one gas turbine engine as defined above fixed to the fuselage.

[0036] DESCRIPTION OF THE FIGURES

[0037] Figure 1 is an example of an aircraft comprising at least one propulsion system;

[0038] Figure 2 is a schematic longitudinal cross-sectional view of a propulsion system according to a first embodiment of the invention;

[0039] Figure 3 is a schematic longitudinal cross-sectional view of a propulsion system according to a second embodiment of the invention;

[0040] Figure 4 is a schematic perspective view of an accessory drive housing assembly according to one possible embodiment of the invention;

[0041] Figure 5 is a schematic axial cross-sectional view of the accessory drive housing assembly of Figure 4; Figure 6 is an axial cross-sectional view of part of the accessory drive housing assembly of Figure 5;

[0042] Figure 7 is a partial enlarged view of figure 6;

[0043] Figure 8 is a perspective view of an oil deflector from the accessory drive housing assembly of Figure 6.

[0044] Across all figures, similar elements bear identical references.

[0045] DETAILED DESCRIPTION

[0046] 1-axis turbine engine

[0047] Figure 1 illustrates an aircraft 100 conforming to an embodiment of the invention. The aircraft 100 comprises a fuselage on which at least one propulsion system is fixed. The propulsion system is a gas turbine engine 1.

[0048] The gas turbine engine 1 has a principal direction extending along a longitudinal axis X and comprises, from upstream to downstream in the direction of gas flow in the gas turbine engine 1 when in operation, a fan section 2 and a primary casing 3, often called the "gas generator," having a compressor section 4, 5, a combustion chamber 6, and a turbine section 7, 8, which form a hub 3a of the primary casing. The primary casing 3 also includes a primary casing 3b surrounding the compressor section 4, 5, the combustion chamber 6, and the turbine section 7, 8.

[0049] In this description, the axial direction with respect to a given axis corresponds to the direction of the axis, and a radial direction is a direction perpendicular to and passing through that axis. Unless otherwise specified, internal (respectively, inside) and external (respectively, outside) are used with reference to a radial direction such that the internal part or face of an element is closer to the axis than the external part or face of the same element.

[0050] In operation, an airflow entering the gas turbine engine 1 is divided between a primary airflow F1 and a secondary airflow F2, which flow from upstream to downstream in the gas turbine engine 1.

[0051] The primary airflow F1 flows in a primary channel 13a inside the primary body 3, passing successively through the compressor section 4, 5, the combustion chamber 6 where it is mixed with fuel to serve as an oxidizer, and the turbine section 7, 8. The passage of the primary airflow F1 through the turbine section 7, 8 receiving energy from the combustion chamber 6 causes a rotation of the rotor of the turbine section 7, 8, which in turn drives the rotation of the rotor of the compressor section 4, 5 as well as a rotor part 9 of the blower section 2.

[0052] In the case of a fan section 2 which is shrouded, the secondary airflow F2 (also called "bypass airflow") flows in a secondary channel 13b around the primary body 3. The secondary airflow F2 cools the periphery of the primary body 3 and is used to generate most of the thrust supplied by the gas turbine engine 1.

[0053] The gas turbine engine 1 can be a twin-spool gas turbine engine. In such a configuration, the compressor section 4, 5 can comprise a low-pressure compressor 4 and a high-pressure compressor 5. The turbine section 7, 8 can comprise a high-pressure turbine 7 and a low-pressure turbine 8. The rotor of the high-pressure compressor 5 is driven in rotation by the rotor of the high-pressure turbine 7 via a high-pressure shaft 10. The rotor of the low-pressure compressor 4 and the rotor portion 9 of the blower section 2 are driven in rotation by the rotor of the low-pressure turbine 8 via a low-pressure shaft 11.Although such an embodiment is not illustrated, the gas turbine engine 1 can also be a three-shaft gas turbine engine, the turbine section 7, 8 then further comprising an intermediate turbine, positioned between the high-pressure turbine 7 and the low-pressure turbine 8 and configured to drive the rotor of the low-pressure compressor 4 via an intermediate shaft. The blower rotor 9 and the rotor of the high-pressure compressor 5 remain driven by the low-pressure shaft 11 and the high-pressure shaft 10, respectively.

[0054] The low-pressure shaft 11 is generally housed, along a portion of its length, within the high-pressure shaft 10 and is coaxial with it. The low-pressure shaft 11 and the high-pressure shaft 10 may be co-rotating, that is, driven in the same direction around the longitudinal axis X. Alternatively, they may be counter-rotating, that is, driven in opposite directions around the longitudinal axis X. If applicable, the intermediate shaft is housed between the high-pressure shaft 10 and the low-pressure shaft 11. The intermediate shaft and the low-pressure shaft 11 may be co-rotating or counter-rotating.

[0055] The fan section 2 can be shrouded or unshrouded. Figures 2 and 3 illustrate two embodiments in which the gas turbine engine 1 comprises, respectively, a shrouded fan section 2 and an unshrouded fan section 2. In the case of a shrouded fan section 2, as illustrated in Figure 2, the fan section 2 includes a fan housing 12, and the fan rotor 9 is housed within the fan housing 12.

[0056] A shrouded blower section 2 includes a blower rotor 9 extending upstream of a blower stator 16. The blades 17 of the blower stator 16 are then generally referred to as outlet guide vanes (OGV) and have a variable pitch relative to the blower stator hub.

[0057] In an unshod fan section 2, corresponding to the second type of engine illustrated in Figure 3, the fan section 2 is not enclosed by a fan casing. Because the fan section 2 is unshod, the blades 14 of the fan rotor 9 have variable pitch. Propulsion systems comprising at least one unshod fan rotor 9 are known as "open rotor" or "unducted fan." The gas turbine engine 1 may include two unshod, counter-rotating fan rotors 9. Such a gas turbine engine 1 is known by the acronym CROR for "Contra-Rotating Open Rotor" or UDF for "Unducted Double Fan." The blower rotor(s) 9 can be placed at the rear of the primary body 3 so as to be of the pusher type or at the front of the primary body 3 so as to be of the tractor type.Alternatively, the gas turbine engine 1 may comprise a single unducted fan rotor 9 and an unducted fan stator 16 (rectifier). Such a gas turbine engine 1 is known by the English acronym USF for "Unducted Single Fan". In the case of a USF-type gas turbine engine 1, the blades 17 of the rectifier 16 are fixed in rotation relative to the X-axis of rotation of the upstream fan rotor 9 and therefore do not experience centrifugal force. The blades 17 of the rectifier 16 also have variable pitch.

[0058] Accessory drive housing assembly

[0059] The gas turbine engine 1 comprises structural arms 20, a radial drive shaft 21, a power transfer shaft 22, and an accessory drive housing assembly 23. The primary runner 13a, and the secondary runner 13b if present, are traversed by the structural arms 20, which extend radially with respect to the longitudinal axis X. In the example in Figure 2, the structural arms 20 connect the fan housing 12 and the hub 3a of the primary body. In the example in Figure 3, the structural arms 20 connect the housing 3b of the primary body and the hub 3a of the primary body. The radial drive shaft 21 is housed in a structural arm 20 and extends substantially radially with respect to the longitudinal axis X. A radially internal end of the radial drive shaft 21 is coupled to the high-pressure shaft 10 by means of bevel gears.In this way, the radial drive shaft 21 is rotated by the high-pressure shaft 10 when the gas turbine engine 1 is running, as illustrated in Figures 2 and 3. In an alternative embodiment, the radial drive shaft 21 could be rotated by the low-pressure shaft 11. The radially external end of the radial drive shaft 21 is coupled to one end of the power transfer shaft 22. The radial drive shaft 21 rotates a gear train of the accessory drive housing assembly 23 of the gas turbine engine 1. The accessory drive housing assembly 23 is conventionally arranged in a casing forming a peripheral enclosure of the gas turbine engine 1.Preferably, the accessory drive housing assembly 23 is located upstream of the combustion chamber 6, even more preferably axially between the low pressure compressor 4 and the high pressure compressor 5 along the longitudinal axis X of the gas turbine engine 1 so as not to be subjected to excessively high temperatures at the combustion chamber 6.

[0060] The accessory drive housing assembly 23 includes an accessory drive housing 25, at least one accessory 26, and at least one drive shaft 27 connecting the accessory 26 to the accessory drive housing 25.

[0061] As illustrated in Figure 5, the accessory drive housing 25 comprises a housing 28 having a first wall 30 and a second wall 31 opposite the first wall 30. The accessory drive housing 25 also comprises a gear train mounted inside the housing 28, between the first wall 30 and the second wall 31.

[0062] The gear train comprises a plurality of gears 29 meshing with each other, each gear 29 being supported by a respective drive shaft 32. Each drive shaft 32 is rotatably mounted relative to the housing 28. The drive shafts 32 each extend along an axis X' which is possibly, but not necessarily, parallel to the longitudinal axis X of the gas turbine engine 1. The axes X' of the drive shafts 32, which are also the axes of rotation of the gears 29, are thus optionally parallel to each other.

[0063] The accessories 26 are arranged at the ends of the transmission shafts 32. Each accessory 26 is fixed to one of the first wall 30 and the second wall 31 of the housing 28. Each accessory 26 includes a drive shaft 27 (not shown in figures 4 and 5) which is rotationally coupled to a transmission shaft 32 of the gear train.

[0064] Each drive shaft 32 of the gear train defines a line of the accessory drive housing 25.

[0065] The gears 29 of the gear train mesh with each other, so that a rotation of one of the gears 29 simultaneously causes the other gears 29 to rotate around their respective axes of rotation. Each gear 29 has a diameter adapted to transmit a given rotational speed to the drive shaft 32 of its line in the accessory drive housing 25, for example, depending on the accessory 26 of that line which is driven by the drive shaft 32. As illustrated in Figures 2 and 3, the power transfer shaft 22 forms a power input for the gear train. In operation, the power transfer shaft 22 provides input power to the gear train, which enables the gear wheels 29 and their respective transmission shafts 32 to rotate, and consequently the accessories 26 coupled to the transmission shafts 32.

[0066] Figures 6 and 7 illustrate on a larger scale a line of the accessory drive housing 25 comprising a drive shaft 32a of the plurality of drive shafts 32 and a gear 29a of the plurality of gears 29. The drive shaft 32a is connected to an accessory 26a of the plurality of accessories 26 via a transmission system 40. The accessory 26a comprises a drive shaft 27a connecting the accessory 26 to the accessory drive housing 25. The power transmission system 40 is shown in Figure 5 in a recess 15 of the first wall 30 of the housing 28, said recess 15 extending towards the second wall 31. It may, however, be located partially or totally outside the housing 28.

[0067] For clarity, the housing 28 is not shown in figures 6 and 7.

[0068] The transmission shaft 32a comprises a first part 42 oriented from the gear 29a towards the first wall 30 and which includes a first end 44a of the transmission shaft 32a. The transmission shaft 32a further comprises a second part 43 oriented from the gear 29a towards the second wall 31 and which includes a second end 44b of the transmission shaft 32a.

[0069] The first part 42 of the transmission shaft 32a has a frustoconical wall 41 with a decreasing cross-section towards the first wall 30 and extending towards the first wall 30 by the first end 44a. The first end 44a is cylindrical and may include splines on its external wall relative to the X' axis of the transmission shaft 32a.

[0070] The transmission system 40 is arranged at the first end 44a of the transmission shaft 32a, so as to transmit the rotational torque of the gear 29a to the drive shaft 27a of the accessory 26a.

[0071] 40 Transmission System

[0072] The transmission system 40 includes a pinion 45 and a crown 46.

[0073] The pinion 45 has external teeth 45a. The pinion 45 is fixedly mounted on the transmission shaft 32a, preferably on the first cylindrical end 44a. The pinion 45 may include a radially internal surface provided with splines cooperating along the X' axis of the transmission shaft 32a with splines in the external wall of the first end 44, such that a rotation of the transmission shaft 32a relative to the housing 28 causes a rotation of the pinion 45 relative to the housing 28 around the X' axis.

[0074] The crown 46 has a rotation axis Y parallel to the rotation axis X' of the transmission shaft 32a.

[0075] The ring 46 includes a cylindrical portion 47 surrounding the pinion 45. The cylindrical portion 47 of the ring 46 includes a first portion 47a having internal teeth 48 which mesh with the external teeth 45a of the pinion 45, such that a rotation of the pinion 45 relative to the housing 28 causes a rotation of the ring 46 relative to the housing 28. The first portion 47a of the cylindrical portion 47 of the ring 46 includes an annular rim 49 which extends radially outwards relative to the Y-axis from a first end 47c of the proximal cylindrical portion 47 of the first wall 30.

[0076] The cylindrical portion 47 further comprises a second portion 47b extending the first portion 47a around the Y axis in a direction opposite to the transmission shaft 32a, towards the accessory 26a. The second portion 47b extends axially along the Y axis to a second end 47d opposite the first end 47c.

[0077] The crown 46 further includes a hub 50 with a diameter smaller than the cylindrical part 47, and a frustoconical part 51 with a decreasing cross-section extending from the second end 47d of the cylindrical part 47 to the hub 50.

[0078] Opposite walls of the pinion 45, the second portion 47b of the first cylindrical part 47, the frustoconical wall 51 and the hub 50 of the ring 46 define a lubrication cavity 52.

[0079] The hub 50 extends axially along the Y axis from a first end 50a opposite the pinion 45 to a second opposite end 50b, which forms a downstream axial end of the ring 46.

[0080] The lubrication cavity 52 is more precisely defined by the interior of the second portion 47b and by the interior of the frustoconical wall 51, and is axially delimited by the pinion 45 upstream and by the first end 50a of the hub 50 downstream.

[0081] The hub 50 includes a central through opening 53 extending along the Y axis, in which the drive shaft 27a of the accessory 26a is mounted.

[0082] The ring gear 46 comprises a central cylindrical portion 54 extending into the lubrication cavity 52 from the first end 50a of the hub 50 towards the transmission shaft 32a, so as to axially extend the central opening 53 of the hub 50. The central cylindrical portion 54 extends into the lubrication cavity 52 to a free end 54a. The free end 54a can be located axially along the Y-axis at the level of the second portion 47b of the cylindrical portion 47. A free space is thus defined in the lubrication cavity 52 between the free end 54a and the pinion 45 and the internal teeth 48 in the lubrication cavity 52. The diameter of the central cylindrical part 54 is less than that of the hub 50, although the central opening 53 has a constant diameter from the free end 54a of the central cylindrical part 54 to the second opposite end 50b of the hub 50.

[0083] The transmission system 40 is designed to receive the drive shaft 27a of the accessory 26a. More specifically, the ring gear 46 is designed to be connected to the drive shaft 27a of the accessory 26a. This drive shaft 27a is engaged in the central opening 53 and comprises external teeth meshing with internal teeth of the central opening 53.

[0084] In operation, the gears 29 of the gear train drive in rotation the gear 29a, then the transmission shaft 32a, the pinion 45, then the ring gear 46, and finally the accessory 26a via the drive shaft 27a. The external diameter of the pinion 45 is optionally smaller than the diameter of the central opening 53, so that the transmission system 40 allows a speed reduction between a first rotational speed œ1 of the transmission shaft 32a and a second rotational speed OÜ2 of the drive shaft 27a of the accessory 26a in a compact space.

[0085] The transmission system 40 also includes a lubrication oil nozzle 55.

[0086] The lubricating oil jet 55 can be formed in the drive shaft 27a of the accessory 26a, or alternatively be connected to an axial end of the drive shaft 27a in the central opening 53 so as to be driven in rotation relative to the housing 28 by the drive shaft 27a.

[0087] The lubrication oil nozzle 55 is mounted in the cylindrical central part 54, more precisely in the central opening 53 of the hub 50. The lubrication oil nozzle 55 includes an expulsion portion 55a extending axially along the Y axis in the lubrication cavity 52 beyond the cylindrical central part 54.

[0088] The expulsion portion 55a of the lubricating oil nozzle 55 includes one or more oil expulsion orifices 55b, which extend radially with respect to the Y axis of rotation of the ring 46. Preferably, the lubricating oil nozzle 55 includes between two and five orifices, for example 4 orifices in order to allow uniform lubrication regardless of the rotational speed of the lubricating oil nozzle 55.

[0089] The lubricating oil nozzle 55 is designed to be supplied with lubricating oil via the drive shaft 27a. More specifically, the drive shaft 27a may include an internal conduit 55c connected to a lubricating oil reservoir, which carries the lubricating oil from the reservoir to the lubricating oil discharge ports 55b of the lubricating oil nozzle 55. Preferably, the accessory 26a is thus an oil pump designed to supply the lubricating oil nozzle 55.

[0090] When the lubricating oil nozzle 55 rotates due to the rotation of the drive shaft 27a, the lubricating oil is expelled radially from the lubricating oil expulsion ports 55b in the form of jets into the lubrication cavity 52 by centrifugal force. Thus, the lubricating oil nozzle 55 is configured, when rotating, to expel the lubricating oil.

[0091] In addition, the transmission system 40 includes an oil deflector 56 configured to guide the lubricating oil expelled by the lubricating oil nozzle 55 to the internal teeth 48 of the crown 46.

[0092] The oil deflector 56 is fixedly mounted on the ring 46, so that a rotation of the ring 46 relative to the housing 28 causes a rotation of the oil deflector 56 relative to the housing 28. The oil deflector 56 is located in the lubrication cavity 52. ​​It can be fixedly mounted on the cylindrical central portion 54 of the ring 46.

[0093] The oil deflector 56 includes a tubular portion 56a extending around the cylindrical central part 54 and fixed to this cylindrical central part 54, for example by screwing or shrink fitting or any other suitable fixing, so that the oil deflector 56 is rotationally fixed to the ring 46.

[0094] The oil deflector 56 further includes a central portion 57 having a first guiding surface 57a extending perpendicularly to the Y-axis of rotation of the ring 46, i.e., radially with respect to this Y-axis. The central portion 57 includes a central hole in which the lubricating oil nozzle 55 is mounted so that the lubricating oil expulsion portion 55a is surrounded by the oil deflector 56. Alternatively, the central portion 57 may include several holes so that several lubricating oil nozzles 55 can be used, for example, to better distribute the lubricating oil on the oil deflector 56.

[0095] The oil deflector 56 finally includes a peripheral portion 58 surrounding the central portion 57 and having a second guiding surface 58a. The peripheral portion 58 and the second guiding surface 58a are frustoconical in shape with a cross-section increasing from the central portion 57 towards the internal teeth 48 of the ring gear 46.

[0096] The oil deflector 56 has a free edge 59 located opposite the internal teeth 48. The peripheral portion 58 and the second guiding surface 58a thus extend respectively from the central portion 57 and the first guiding surface 57a towards the internal teeth 48 of the ring 46 to the free edge 59.

[0097] The free edge 59 is located at an axial distance along the Y axis from the internal teeth 48 of the crown 46 of less than 50 millimeters, preferably between 1 and 25 millimeters.

[0098] The free edge 59 has a diameter less than the crown head diameter 46, defined as the diameter of a circle passing through the apexes of the teeth of the internal teeth 48 of the crown 46.

[0099] Since the lubricating oil expulsion orifices 55b extend radially with respect to the Y-axis of rotation of the ring gear 46, and therefore of the drive shaft 27a and the lubricating oil nozzle 55, the lubricating oil is expelled from the nozzle 55 in jets in a radial direction, regardless of the rotational speed of the lubricating oil nozzle 55. In other words, the rotational speed of the drive shaft 27 does not change the direction of the lubricating oil jets. The orientation of the lubrication oil expulsion orifices 55b in a radial direction with respect to the Y axis therefore allows better control of the direction of the lubricating oil jets expelled from the different orifices 55b, whereas a non-radial orientation of the orifices 55b would produce jets in very different directions depending on the rotation speed of the lubricating oil expulsion nozzle 55.Depending on the rotational speed of the nozzle 55, the lubricating oil jets then come into contact either with the first guide surface 57a or directly with the second guide surface 58a. Then, due to the centrifugal force resulting from the rotation of the ring gear 46 and thus the oil deflector 56, the lubricating oil is guided successively by the first guide surface 57a and then by the second guide surface 58a, or solely by the second guide surface 58a if applicable, towards the internal teeth 48 of the ring gear 46. Upon reaching the free edge 59 of the second guide surface 58a, the lubricating oil is forced, by centrifugal force, onto the internal teeth 48 of the ring gear 46, consequently spreading via the contact of the internal teeth 48 with the external teeth 45a of the pinion 45, to effectively lubricate these internal teeth. 48 and external 45a.

[0100] Thus, the oil deflector 56 is configured to guide the lubricating oil expelled by the lubricating oil nozzle 55 to the internal teeth 48 of the ring gear 46. The oil deflector 56 allows better control of the lubrication of the transmission system 40 by reducing the distance between the internal teeth 48 and the lubricating oil nozzle 55.

[0101] In an embodiment illustrated in Figure 8, the oil deflector 56, and more specifically its peripheral portion 58, may comprise a plurality of guide teeth 60 formed at the free edge 59 on the second guide surface 58a. The guide teeth 60 are uniformly distributed around the entire periphery of the second guide surface 58a around the Y-axis and are separated by a plurality of inter-tooth spaces 61, each inter-tooth space 61 separating two successive guide teeth 60. The guide teeth 60 and the inter-tooth spaces 61 are dimensioned so that each tooth of the internal teeth 48 of the ring gear 46 is positioned opposite an inter-tooth space 61.

[0102] Thus, during the guidance of the lubricating oil on the second guiding surface 58a by centrifugal force resulting from the rotation of the ring gear 46 and therefore of the oil deflector 56, the lubricating oil concentrates in the inter-tooth spaces 61, and more effectively lubricates each tooth of the internal teeth 48 of the ring gear 46 located opposite the inter-tooth spaces 61. Consequently, less oil reaches an undesired area, i.e., a different tooth of the ring gear 46, so that the same quantity of lubricating oil provides more effective lubrication of the transmission system 40. Finally, for the support of the transmission system 40, a first bearing 62 can be arranged around the first cylindrical portion 47 of the ring gear 46.It can thus include a ring radially internal with respect to the Y axis in radial contact with the first cylindrical part 47 of the crown 46 and in axial abutment against the annular rim 49 of the first cylindrical part 47. It can also include a ring radially external and bearings, for example of roller type, which are mounted radially with respect to the Y axis between the inner ring and the outer ring.

[0103] An internal nut 63 can be mounted on the first cylindrical portion 47, for example between the radially internal ring of the first bearing housing 62 and the second end 47b of the first cylindrical portion 47. The internal nut 63 can be screwed onto the first cylindrical portion 47, and allows the first bearing housing 62, and more particularly its radially internal ring, to be held against the annular rim 49 of the first cylindrical portion 47.

[0104] A second bearing support 64 can be arranged around the second cylindrical portion 50. It can thus comprise a ring radially internal to the Y-axis in radial contact with the frustoconical portion of the ring 46, a ring radially external, and bearings, for example, of the roller or ball type. The second bearing support 64, and more particularly its radially internal ring, is axially abutted along the Y-axis against an external wall of the frustoconical wall 51.

[0105] To retain the radially external rings of the first and second bearing housings 62 and 64, and to retain the ring 46 axially, the transmission system includes a ring support 65 fixed to the first wall 30, to which the radially external rings 52b and 53b are attached. The ring support 65 surrounds at least partially the ring 46. More specifically, it comprises a first radial surface 65a, a second radial surface 65b, and a frustoconical wall 65c of decreasing cross-section connecting the first radial surface 65a and the second radial surface 65b. The first radial surface 65a has a larger diameter than the second radial surface 65b.The first radial surface 65a is located axially on the Y axis around the first bearing support 62, and the second radial surface 65b is located axially on the Y axis in contact with the second bearing support 64 in order to hold it axially against the frustoconical wall 51.

[0106] Finally, a second accessory 26b may be mounted on the drive shaft 32a, on the end 44b of the second part 43. This second accessory 26b may be any accessory that can be driven by an accessory drive unit, such as a pump for hydraulic power generation, fuel supply, lubrication, or an electric generator for electrical power generation, etc. The second accessory 26b includes a drive shaft 27b that is rotationally fixed to the drive shaft 32a, such that a rotation of the drive shaft 32a causes a rotation of the drive shaft 27b. The second accessory 26b is mounted against the second wall 31 of the housing 28.

Claims

DEMANDS 1. Accessory drive housing (25) comprising: - a casing (28) comprising a first wall (30) and a second wall (31) opposite the first wall (30); - a transmission shaft (32; 32a) mounted to rotate relative to the housing (28), the transmission shaft (32; 32a) extending transversely between the first wall (30) and the second wall (31), and comprising an end (44a); - a transmission system (40) arranged at the end (44a) of the transmission shaft (32; 32a) and configured to transmit power from the transmission shaft (32; 32a) to a drive shaft (27; 27a) of an accessory (26; 26a), the transmission system (40) comprising: a pinion (45) fixedly mounted on the transmission shaft (32; 32a), the pinion (45) comprising external teeth (45a), a ring gear (46) adapted to be connected to the drive shaft (27; 27a) of the accessory (26;26a), the ring (46) comprising an internal toothing (48), in contact with the external toothing (45a) of the pinion (45), such that a rotation of the pinion (45) relative to the housing (28) causes a rotation of the ring (46) relative to the housing (28), a nozzle (55) adapted to be driven in rotation relative to the housing (28) and configured, when in rotation, to expel lubricating oil, and an oil deflector (56) configured to guide the lubricating oil expelled by the nozzle (55) to the internal toothing (48) of the ring (46).; 2. Accessory drive housing (25) according to claim 1, in which the oil deflector (56) is fixedly mounted on the ring (46), such that a rotation of the ring (46) relative to the housing (28) causes a rotation of the oil deflector (56) relative to the housing (28).

3. Accessory drive housing (25) according to claim 2, in which the ring (46) includes a cylindrical central part (54) adapted to be connected to the drive shaft (27; 27a) of the accessory (26; 26a), the oil deflector (56) being mounted on the cylindrical central part (54).

4. Accessory drive housing (25) according to any one of claims 1 to 3, wherein the oil deflector (56) comprises: - a central portion (57) having a first guiding surface (57a) extending perpendicularly to an axis of rotation of the ring (46), and - a peripheral portion (58) surrounding the central portion (57), the peripheral portion (58) featuring a second guide surface (58a) of frustoconical shape, extending from the first guide surface (57a) towards the internal teeth (48) of the ring (46), so that the lubricating oil expelled by the nozzle (55) is guided successively by the first guide surface (57a) and then by the second guide surface (58a) or only by the second guide surface (58a) towards the internal teeth (48) of the ring (46).

5. Accessory drive housing (25) according to claim 4, in which the oil deflector (56) has a free edge (59) located opposite the internal teeth (48) of the ring gear (46), the peripheral portion (58) extending to the free edge (59) of the oil deflector (58).

6. Accessory drive housing (25) according to claim 5, in which the free edge (59) has a diameter less than the crown head diameter (46), the crown head diameter (46) being defined as the diameter of a circle passing through the apexes of the teeth of the internal teeth (48).

7. Accessory drive housing (25) according to any one of claims 5 and 6, wherein the free edge (59) of the oil deflector (56) is separated from the internal teeth (48) of the ring gear (46) by a distance of less than 50 millimeters.

8. Accessory drive housing (25) according to any one of claims 5 to 7, wherein the peripheral portion (58) comprises a plurality of guide teeth (60), the guide teeth (60) being separated by an inter-tooth space (61) between two successive guide teeth (60) for the passage of oil between the two successive guide teeth (60), and being oriented so that each tooth of the internal teeth (48) of the ring (46) is located opposite an inter-tooth space (61) of the peripheral portion (58).

9. Accessory drive housing (25) according to any one of claims 1 to 8 in combination with claim 3, wherein the oil deflector (56) comprises a tubular portion (56a) extending around the cylindrical central part (54) of the ring (46) and fixed to the cylindrical central part (54) of the ring (46).

10. Accessory drive housing (25) according to any one of the preceding claims, in which the nozzle (55) comprises a plurality of oil expulsion orifices (55b) extending radially with respect to a rotation axis (Y) of the ring (46).

11. Accessory drive housing assembly (23), comprising an accessory drive housing (25) according to any one of the preceding claims and an accessory (26; 26a) comprising a drive shaft (27; 27a), the drive shaft of the accessory (27; 27a) being connected to the ring (46) of the transmission system (40).

12. Accessory drive housing assembly (23) according to claim 11, wherein the accessory (26;26a) is an oil pump, the oil pump being suitable for supplying the nozzle (55) with lubricating oil.

13. Accessory drive housing assembly (23) according to any one of claims 11 and 12, wherein the accessory (26; 26a) is a first accessory, the accessory drive shaft (27; 27a) is a first drive shaft and the end of the drive shaft (44a) is a first end, the housing assembly (23) comprising a second accessory (26b) comprising a second drive shaft (27b), the drive shaft (32; 32a) comprising a second end (44b) opposite the first end (44a), the second end (44b) of the drive shaft being configured to drive in rotation the second drive shaft (27b) of the second accessory (26b).

14. Gas turbine engine (1) comprising a compressor section (4;5) including a compressor rotor, a turbine section (7;8) including a turbine rotor and a shaft (10;11) connecting the turbine rotor to the compressor rotor so that in operation a rotation of the turbine rotor drives a rotation of the compressor rotor, an accessory drive housing assembly (23) according to any one of claims 11 to 13, a power transfer shaft (22) and a radial drive shaft (21) connecting the shaft (10;11) to the accessory drive housing (25) via the power transfer shaft (22) to drive the transmission shaft (32;32a) of the accessory drive housing (23) into rotation.

15. Aircraft (100), comprising a fuselage and at least one gas turbine engine (1) according to claim 14, fixed to the fuselage.

Images