Aircraft propulsion system comprising a crankcase equipped with a passive gravity-fed lubricant recovery system and equipment through which a line of drains passes.

Abstract

An aircraft propulsion system comprising an engine with a hub supporting blades and a casing, including: a. at least two arms uniformly distributed around the engine hub, b. a hub enclosure (20) located at the hub and opposite a first face of the casing, c. a drain box (24) located opposite a second face of the casing, d. a line of drains connecting the hub enclosure (20) to the drain box (24), e. an engine inlet stage lubrication housing (30) adjacent to at least one arm of the casing and opposite the second face of the casing, the propulsion system including equipment adjacent to the engine inlet stage lubrication housing (30), the line of drains extending through the equipment. Figure for the abstract: [Fig 3]

Description

Title of the invention: Aircraft propulsion unit comprising a crankcase equipped with a passive gravity-fed lubricant recovery system and equipment through which a drain line passes. Technical field

[0001] The invention relates technically to propulsion systems, particularly aircraft propulsion systems, and in particular, the lubrication of such propulsion systems. Previous techniques

[0002] 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 housing 1 is provided with a plurality of arms distributed uniformly 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.

[0003] The propulsion unit housing 1 also includes a passive gravity-fed lubricant recovery system. In such a propulsion unit housing 1, lubricant recovery occurs, in particular, at the hub 2 of the propulsion unit. To this end, a hub housing 20 is provided near the hub 2 to collect lubricant leaks at this point. This hub housing 20 must be connected to a drain box 24 (a "drain mast") located on the other side of the propulsion unit housing 1.

[0004] To achieve this, a line of drains 21,23 is generally used following the fifth arm 15, called the 6 o'clock arm.

[0005] In the context of the development of new paddle propulsion groups, the reduction in volume has become particularly important.

[0006] In order to develop more compact propulsion units, the layout of the drain line may need to be changed. In some extreme cases, a significant lack of space arises for its installation, particularly due to the placement of lubricant reservoirs. Indeed, a lubrication chamber for the inlet stage, located at the 6 o'clock position on the arm, is adjacent to an auxiliary lubricant reservoir 33, which limits the passage of the drain line. This space constraint is amplified when the minimum slope for lubricant drainage is taken into account.

[0007] 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 is connected to the hub housing 20, and a third drain 23 is connected to the box. Drains 24 are also illustrated. Due to sizing, compactness, and placement constraints of the propulsion unit components, it is not possible to modify the location of these components, nor is it possible to modify the propulsion unit casing 1. The drain line 21, 22, 23 must therefore pass through a piece of equipment, specifically the auxiliary lubricant reservoir 33.

[0008] More specifically, the lubrication chamber of the inlet stage of the propulsion system comprises 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, referred to 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 inlet stage of the propulsion system in order to reuse it in a lubrication cycle.

[0009] Finally, a casing extends in front of the lubrication enclosure of the inlet stage of the propulsion system.

[0010] The auxiliary lubricant reservoir 33 is located between the lubrication chamber of the input stage, the arm at 6 o'clock in which the general recovery line 34 is provided, and the housing. This reservoir also includes a filling line extending towards the hub 2.

[0011] In such a powertrain, 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 powertrain, the drain line 21, 22, 23 must be connected to a conduit located in the housing of the lubrication chamber of the inlet stage of the propulsion system at the level of the fifth structural arm 15. Indeed, the fifth arm 15 allows the flow velocity to be maximized due to its orientation at 6 o'clock.

[0012] However, the outlet of this conduit 32 is arranged in such a way that the auxiliary lubricant reservoir 33 is arranged on the path to the drain box 24.

[0013] There is a need for a drain routing to connect the outlet of the line 32 to the drain box 24 despite the presence of the auxiliary lubricant reservoir 33. Description of the invention

[0014] The invention relates to an aircraft propulsion unit comprising a casing and an engine equipped with a hub supporting blades, the casing comprising:

[0015] a. at least two arms evenly distributed around the motor hub,

[0016] b. a hub enclosure arranged to collect lubricant leaks at the hub and positioned opposite a first face of the housing,

[0017] c. a drain box arranged opposite a second face of the casing,

[0018] d. a line of drains connecting the hub housing to the drain box,

[0019] e. a lubrication chamber for the engine input stage adjacent to at least one arm of the crankcase and positioned opposite the second face of the crankcase,

[0020] The propulsion unit includes equipment adjacent to the crankcase and lubrication chamber of 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.

[0021] 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 conduit disposed in an arm of the housing, the second drain being connected to the other end of the conduit by means of a connection.

[0022] The second drain and the connection may be included in the equipment.

[0023] The connection can be disposed on the outside of the equipment casing, while the second drain is disposed at least partly in the equipment.

[0024] The drain line may successively comprise 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.

[0025] 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 enclosure to a second wall and encompassing the connection where present.

[0026] The equipment may be an auxiliary lubricant reservoir or an air line.

[0027] 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.

[0028] The lubrication enclosure of the inlet stage in which all or part of the equipment, the second drain passing through it and the connection, at least one passage provided in the equipment and, possibly, the isolation line can be made of a single piece.

[0029] The single part can be produced by casting or, more advantageously, by additive manufacturing. Brief description of the drawings

[0030] 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:

[0031] - Figure [Fig.1] illustrates a front view of a propulsion unit housing;

[0032] - Figure [Fig.2] is a cross-sectional view of a propulsion unit housing according to the state of the technique,

[0033] - Figure [Fig.3] is a cross-sectional view of a first embodiment of a housing propulsion unit according to the invention,

[0034] - Figure [Fig.4] is a cross-sectional view of a second embodiment of a propulsion unit casing according to the invention, and

[0035] - Figure [Fig. 5] is a cross-sectional view of a third embodiment of a housing propulsion group according to the invention. 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, in particular the auxiliary lubricant tank 33.

[0037] This solution is counterintuitive because it is generally preferable not to place liquids and equipment in close proximity, even when the equipment is a lubricant reservoir. Indeed, in mechanical design, it is preferable to limit fluid connections to a reservoir, which are a source of fatigue. This solution is also counterintuitive because the sealing of the drain line 21, 22, 23 must be guaranteed to avoid damaging the equipment through which it passes or mixing potentially different or incompatible lubricants.

[0038] The effect of such a line of drains 21,22,23 passing through equipment is to maximize the compactness of the propulsion group while ensuring proper flow of liquids in the line of drains 21,22,23 due to a sufficient slope, in particular greater than 2%.

[0039] 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 sealing of the component with respect to lubricant while limiting the volume taken from the overall volume of the component and devoted to the drain passage.

[0040] In particular embodiments, as illustrated in figures [Fig.3] to [Fig.5], the equipment is an auxiliary lubricant reservoir 33, attached to the lubrication enclosure of the turbomachine inlet stage.

[0041] 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.

[0042] A first drain 21 is connected from the hub housing 20 to a conduit 32 provided in the lubrication chamber of the input stage. As described in the introduction, The line 32 is located in the housing of the inlet stage lubrication chamber. A second drain 22 is connected to the outlet of the line 32 provided in the inlet stage lubrication chamber 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.

[0043] 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.

[0044] In a first embodiment illustrated by the figure [Fig.3], the second drain 22 as well as 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.

[0045] 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 arranged so as to be compressed when screwed onto the internal and external threads to ensure the sealing of the assembly.

[0046] In an alternative embodiment, the slope of the conduit 32 formed in the lubrication chamber of the inlet stage is modified to improve the flow of lubricant 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 connection 35 of the reservoir is positioned closer to the hub 2 than in the first or second embodiment.

[0047] 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.

[0048] 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, as well as the connection 35, the passages in the wall of the auxiliary lubricant reservoir 33, and, optionally, the isolation line, are made of a single piece. The risk of leaks is then reduced at the expense of the complexity of the component to be manufactured. Alternatively, the reservoir, the second drain 22, and the lubrication chamber of the inlet stage are made of a single piece.

[0049] When the reservoir, the second drain 22, and optionally 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 produced by additive manufacturing. Geometric complexity is then no longer a limitation to its production.

[0050] Finally, the invention has been illustrated when the equipment through which a drain passes is an auxiliary lubricant reservoir 33. However, the invention is not limited to such equipment. The equipment may be a computer, an air duct, oil or fuel pumps, see the PADs of an accessory gear box (AGB), air-to-air or air-to-fluid heat exchangers

[0051] 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) arranged to collect lubricant leaks 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 line of drains connecting the hub enclosure (20) to the drain box (24), e.an engine inlet stage lubrication chamber adjacent to 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 chamber, 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.

2. Aircraft propulsion unit according to claim 1, wherein the drain line successively comprises a first drain (21) connected to the hub housing (20) and a second drain (22) connected to a 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 drain line comprises successively a first drain (21) connected to the hub enclosure (20) directly connected to a third drain (23) connected to the drain box (24) the drain line 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. Aircraft propulsion unit according to any one of claims 1 to 6, wherein the equipment is a lubricant tank or an air line.

8. Method of manufacturing the aircraft propulsion unit according to any one of claims 1 to 7, 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.

9. Method of manufacturing the aircraft propulsion unit according to any one of claims 1 to 7, 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.

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

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