Aircraft propulsion unit comprising a casing provided with a passive gravity lubricant recovery system and a piece of equipment traversed by a drain line

Abstract

The invention relates to an aircraft propulsion unit comprising an engine provided with a hub supporting blades and a casing, comprising: a. at least two arms distributed uniformly around the hub of the engine, b. a hub enclosure (20) arranged at the hub and arranged facing a first face of the casing, c. a drain box (24) arranged facing a second face of the casing, d. a drain line connecting the hub enclosure (20) to the drain box (24), e. a casing (30) for lubricating the inlet stage of the engine adjacent to at least one arm of the casing and arranged facing the second face of the casing, the propulsion unit comprising a piece of equipment adjacent to the casing and to the casing (30) for lubricating the inlet stage of the engine, the drain line extending through the piece of equipment.

Description

[0001] DESCRIPTION

[0002] TITLE: Aircraft propulsion unit comprising a crankcase equipped with a passive gravity-fed lubricant recovery system and equipment through which a drain line passes

[0003] technical field

[0004] The invention relates technically to propulsion systems, particularly those of aircraft, and in particular, the lubrication of such propulsion systems.

[0005] Previous techniques

[0006] Figure [Fig 1] illustrates a front view of a propulsion unit housing 1, in the center of which is arranged the hub 2 of a propulsion unit supporting blades, not shown in this figure. The hub is external to the engine and of the open-fan type. The housing 1 is equipped with a plurality of arms distributed evenly around the hub 2. Figure [Fig 1] illustrates a propulsion unit housing 1 equipped with eight arms, from the first arm 11 to the eighth arm 18. The fifth arm 15 is called the 6 o'clock arm, by analogy to the hands of a clock indicating 6 o'clock.

[0007] The propulsion unit housing 1 also includes a passive gravity-fed lubricant recovery system. In such a propulsion unit housing 1, lubricant recovery occurs primarily at the hub 2 of the propulsion unit. To achieve this, a hub housing 20 is provided near the hub 2 to collect any lubricant leaks at this point. This hub housing 20 must be connected to a drain mast 24 located on the opposite side of the propulsion unit housing 1.

[0008] To achieve this, a line of drains 21,23 is generally used following the fifth arm 15, called the 6 o'clock arm.

[0009] In the development of new bladed propulsion units, volume reduction has become particularly important. To develop more compact propulsion units, the drain line layout may need to be modified. In some extreme cases, a significant lack of space arises for its installation, notably due to the placement of lubricant reservoirs. Indeed, a lubrication chamber for the inlet stage, located at the 6 o'clock arm, is adjacent to an auxiliary lubricant reservoir 33, which limits the passage of the drain line. This space constraint is amplified when considering the minimum slope for lubricant drainage.

[0010] Figure [Fig 2] is a cross-sectional view of the powertrain housing 1, illustrating the location of the drain line outlets 21, 22, 23, the location of an auxiliary lubricant reservoir 33, and the location of the drain box 24. A first drain 21 connected to the hub housing 20 and a third drain 23 connected to the drain box 24 are also shown. Due to sizing, compactness, and placement constraints of the powertrain components, it is not possible to modify the location of these components, nor is it possible to modify the powertrain housing 1. The drain line 21, 22, 23 must therefore pass through a component, namely the auxiliary lubricant reservoir 33.

[0011] More specifically, the lubrication chamber of the propulsion engine's entry stage includes an inlet chamber 30 connected at its lower end to a general recovery line 34 leading to a main lubricant reservoir and located in the fifth arm 15, known as the 6 o'clock arm, of the propulsion unit casing 1. The inlet chamber 30 allows the recovery of lubricant normally intended for the bearings of the propulsion engine's entry stage for reuse in a lubrication cycle.

[0012] Finally, a casing extends in front of the lubrication chamber of the propulsion inlet stage.

[0013] The auxiliary lubricant reservoir 33 is located between the lubrication chamber of the inlet stage, the arm at 6 o'clock in which the general recovery line 34 is provided, and the casing. This reservoir also includes a filling line extending towards the hub 2.

[0014] In such a propulsion unit, it is necessary to connect the hub housing 20 to the drain box 24 located downstream of the lubrication chamber of the inlet stage via a drain line 21, 22, 23. Due to the compactness of the propulsion unit, the drain line 21, 22, 23 must be connected to a conduit located in the casing of the inlet stage lubrication chamber of the engine at the level of the fifth structural arm 15. Indeed, the fifth arm 15 allows for maximizing the flow velocity due to its 6 o'clock orientation.

[0015] However, the outlet of this pipe 32 is arranged in such a way that the auxiliary lubricant reservoir 33 is located on the path to the drain box 24.

[0016] There is a need for a drain routing to connect the outlet of line 32 to the drain box 24 despite the presence of the auxiliary lubricant reservoir 33.

[0017] Description of the invention

[0018] The invention relates to an aircraft propulsion unit comprising a casing and an engine equipped with a hub supporting blades. The casing comprises: a. at least two arms distributed uniformly around the engine hub; b. a hub enclosure arranged to collect lubricant leaks at the hub and located opposite a first face of the casing; c. a drain box located opposite a second face of the casing; d. a drain line connecting the hub enclosure to the drain box; e. a lubrication chamber for the engine inlet stage adjacent to at least one arm of the casing and located opposite the second face of the casing. The propulsion unit comprises equipment adjacent to the casing and the lubrication chamber for the engine inlet stage. The drain line extends through the equipment to provide a highly compact propulsion unit and a slope that promotes lubricant flow.

[0019] The drain line may successively comprise a first drain connected to the hub housing and a second drain connected to a third drain connected to the drain box and in which the first drain is connected to one end of a pipe disposed in an arm of the housing, the second drain being connected to the other end of the pipe via a connection.

[0020] The second drain and connection can be included in the equipment.

[0021] The connection can be placed on the outside of the equipment casing, while the second drain is placed at least partially inside the equipment.

[0022] The drain line may successively include a first drain connected to the hub enclosure directly connected to a third drain connected to the drain box, the drain line extending through the equipment.

[0023] An isolation conduit may be provided to isolate the drain line from the equipment, the isolation conduit then extending from a first wall of the equipment casing to a second wall and encompassing the connection where present.

[0024] The equipment can be an auxiliary lubricant tank or an air line.

[0025] Another object of the invention is a method of manufacturing a propulsion unit as described above, in which all or part of the equipment, the second drain passing through it as well as the connection, at least one passage provided in the equipment and, optionally, the isolation line can be made in one piece.

[0026] The lubrication enclosure of the entry stage in which all or part of the equipment, the second drain passing through it as well as the connection, at least one passage provided in the equipment and, possibly, the isolation line can be made of a single piece.

[0027] The single part can be produced by casting or, more advantageously, by additive manufacturing.

[0028] Brief description of the drawings

[0029] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0030] - Figure [Fig 1] illustrates a front view of a propulsion unit housing;

[0031] - Figure [Fig 2] is a cross-sectional view of a propulsion unit housing according to the prior art,

[0032] - Figure [Fig 3] is a cross-sectional view of a first embodiment of a propulsion unit housing according to the invention,

[0033] - Figure [Fig 4] is a cross-sectional view of a second embodiment of a propulsion unit housing according to the invention, and

[0034] - Figure [Fig 5] is a cross-sectional view of a third embodiment of a propulsion unit housing according to the invention.

[0035] Detailed description

[0036] In order to solve the technical problem, the inventors had the idea of ​​routing the drain line 21, 22, 23 through a piece of equipment in the propulsion group, specifically the auxiliary lubricant tank 33.

[0037] This solution is counterintuitive because it is generally preferable to keep liquids and equipment away from each other, even if the equipment is a lubricant reservoir. Indeed, in mechanical design, it is preferable to limit fluid connections to a reservoir, as these are a source of fatigue. This solution is also counterintuitive because the leak-tightness of the drain line 21, 22, 23 must be guaranteed to avoid damaging the equipment it passes through or mixing potentially different or incompatible lubricants. The effect of such a drain line 21, 22, 23 passing through equipment is to maximize the compactness of the propulsion unit while ensuring proper fluid flow within the drain line 21, 22, 23 due to a sufficient slope, particularly one greater than 2%.

[0038] An aircraft propulsion unit according to the invention is equipped with at least one component in which a passage is provided for a drain from a line of lubricant drains 21, 22, 23. The passage ensures the seal of the component with respect to lubricant while limiting the volume of the component occupied by the drain.

[0039] In particular embodiments, as illustrated in figures [Fig 3] to [Fig 5], the equipment is an auxiliary lubricant reservoir 33, attached to the lubrication chamber of the turbomachine inlet stage.

[0040] The drain line 21, 22, 23 passes from the hub housing 20 to the drain box 24 through the lubrication enclosure of the input stage and through the auxiliary lubricant reservoir 33. The drain line 21, 22, 23 is sectional in that it comprises at least two drains connected one after the other.

[0041] A first drain 21 is connected from the hub housing 20 to a line 32 provided in the lubrication chamber of the input stage. As described in the introduction, the line 32 is located within the casing of the lubrication chamber of the input stage. A second drain 22 is connected to the outlet of the line 32 provided in the lubrication chamber of the input stage, passing through the auxiliary lubricant reservoir 33. A third drain 23 is connected to the outlet of the second drain 22 and to the drain box 24.

[0042] The second drain 22 then passes through the wall of the auxiliary lubricant reservoir 33, in a sealed manner, for example thanks to the presence of a pre-formed junction in the wall, or thanks to the presence of seals surrounding the drains and compressed against the wall of the auxiliary lubricant reservoir 33.

[0043] In a first embodiment illustrated by the figure [Fig 3], the second drain 22 and the connection 35 of the second drain 22 to the conduit 32 provided in the casing of the lubrication chamber of the inlet stage are immersed in the lubricant of the auxiliary lubricant reservoir 33.

[0044] In a second embodiment illustrated by Figure [Fig 4], the connection 35 of the second drain 22 to the line 32 provided in the lubrication chamber of the inlet stage is not immersed in the lubricant of the auxiliary lubricant reservoir 33, while the second drain 22 is immersed in the lubricant of the auxiliary lubricant reservoir 33. To achieve this, the volume of the auxiliary lubricant reservoir 33 is slightly reduced at the end of the line 32 and a connection 35 is provided on the outside of the wall of the auxiliary lubricant reservoir 33. The connection 35 is made, for example, in the form of a passage through the wall of the auxiliary lubricant reservoir 33, provided with an external thread on the outside of the reservoir and an internal thread on the inside of the reservoir.The conduit 32, provided in the casing of the inlet stage lubrication chamber, is then screwed onto the external thread, while the second drain 22 is screwed into the internal thread. Gaskets are positioned so as to be compressed when screwed onto the internal and external threads to ensure a tight seal.

[0045] In an alternative embodiment, the slope of the conduit 32 formed in the lubrication chamber of the inlet stage is modified to improve lubricant flow in the drain line 21, 22, 23. This modification is particularly relevant when the lubrication chamber of the inlet stage is manufactured by molding. The conduit 32 is then arranged so that the second and third drains 23 have a steeper slope than in the embodiments illustrated in Figures [Fig. 3] and [Fig. 4]. To achieve this, the first drain 21 is connected directly to a connection 35 on the auxiliary lubricant reservoir 33, similarly to the first or second embodiment. The present embodiment differs from these in that the reservoir connection 35 is positioned closer to the hub 2 than in the first or second embodiment.Alternatively, an isolation line is provided to isolate the drain in the auxiliary lubricant reservoir 33 from the lubricant contained therein. The isolation line then extends from a first wall 15a to the second wall 15b of the reservoir and encompasses the connection 35 from the second drain 22 to the first drain 21.

[0046] In each of the embodiments illustrated above, the auxiliary lubricant reservoir 33 can advantageously be constructed so that the wall of the auxiliary lubricant reservoir 33, the second drain 22 passing through it, the connection 35, the passages in the wall of the auxiliary lubricant reservoir 33, and, optionally, the isolation line are formed as a single piece. The risk of leakage is thus reduced at the expense of the complexity of the component. Alternatively, the reservoir, the second drain 22, and the lubrication chamber of the inlet stage are formed as a single piece.

[0047] When the reservoir, the second drain 22, and possibly the lubrication chamber of the inlet stage are made from a single piece, this can be produced conventionally by casting. However, such a part can be more advantageously manufactured by additive manufacturing. Geometric complexity is then no longer a limitation to its production.

[0048] Finally, the invention was illustrated when the equipment traversed by a drain is an auxiliary lubricant reservoir 33. However, the invention is not limited to such equipment. The equipment can be a computer, an air duct, oil or fuel pumps, see the pad inputs of an accessory gear box (AGB), air-to-air or air-to-fluid heat exchangers.

[0049] Similarly, the invention is not limited to a lubricant drain passing through equipment. The drain can be replaced by a fluid conduit, such as for air, water, lubricant, etc.

Claims

DEMANDS 1. Aircraft propulsion unit comprising a casing (1) and an engine having a hub (2) supporting blades, the casing (1) comprising: a. at least two arms distributed uniformly around the hub (2) of the engine, b. a hub enclosure (20) disposed to collect lubricant leaks passively by gravity at the hub (2) and disposed opposite a first face of the casing, c. a drain box (24) disposed opposite a second face of the casing, d. a drain line connecting the hub enclosure (20) to the drain box (24), the drain line comprising a first drain (21) connected to the hub enclosure (20) and a third drain (23) connected to the drain box (24), e.an engine inlet stage lubrication enclosure adjoining at least one crankcase arm and positioned opposite the second crankcase face, the propulsion unit comprising equipment adjacent to the crankcase and the engine inlet stage lubrication enclosure, the propulsion unit being characterized by the fact that the drain line extends through the equipment to provide high compactness of the propulsion unit as well as a slope promoting lubricant flow, the equipment being a lubricant reservoir or an air line.

2. Aircraft propulsion unit according to claim 1, wherein the drain line successively comprises the first drain (21) connected to the hub housing (20) and a second drain (22) connected to the third drain (23) connected to the drain box (24) and wherein the first drain (21) is connected to one end of a conduit (32) disposed in an arm of the casing, the second drain (22) being connected to the other end of the conduit (32) via a connection (35).

3. Aircraft propulsion unit according to claim 2, wherein the second drain (22) and the connection (35) are included in the equipment.

4. Aircraft propulsion unit according to claim 2, wherein the connection (35) is disposed on the outside of the equipment housing, while the second drain (22) is disposed at least partly in the equipment.

5. Aircraft propulsion unit according to claim 1, wherein the first drain (21) connected to the hub enclosure (20) is directly connected to the third drain (23) connected to the drain box (24), the line of drains extending through the equipment.

6. Aircraft propulsion unit according to any one of claims 1 to 5, wherein an isolation conduit is provided to isolate the drain line of the equipment, the isolation conduit then extending from a first wall (15a) of the equipment casing to a second wall (15b) and encompasses the connection (35) when present.

7. Method of manufacturing the aircraft propulsion unit according to any one of claims 1 to 6, wherein all or part of the equipment, the second drain (22) passing through it and the connection (35), at least one passage provided in the equipment and, optionally, the isolation line are made of a single piece.

8. Method of manufacturing the aircraft propulsion unit according to any one of claims 1 to 6, wherein the lubrication enclosure of the inlet stage in which all or part of the equipment, the second drain (22) passing through it and the connection (35), at least one passage provided in the equipment and, optionally, the isolation line are made of a single piece.

9. Method of manufacturing the aircraft propulsion unit according to any one of claims 7 or 8, wherein the single part is produced by casting or by additive manufacturing.

Images