Bypassable thrust reversing device for aircraft engine

Abstract

Thrust reversal device 5 by reversing the direction of rotation of a fan S, for a geared turbofan 1, comprising: a housing 90, a clutch drum 25, mounted rotatably around X and axially movable on X; a planetary reducer consisting of a first toothed gear 40 attached to a turbomachine 2, a second toothed gear 60 attached to a fan S via a geared fan module 12; a plurality of satellites 30 and a satellite carrier 50; characterized in that said planet carrier 50, driven in rotation by said clutch drum 25, is axially mobile, independently of the axial displacement of said clutch drum 25, to allow, a rigid coupling by mesh engagement, with said second toothed gear 60 and / or said first toothed gear 40 by translation of said planet carrier 50 in a first direction D, or with said housing casing 90 by translation in an opposite direction R."Figure for the abbreviation: Figure 5."

Description

Title of the invention: Bypassable thrust reversing device for aircraft engine

[0001] The present invention relates to the field of aircraft engines, and in particular to thrust reversal devices for turbofans, but may also be suitable more generally for all systems requiring reversing the direction of rotation of a mechanism driven in rotation by an engine, without reversing or stopping said engine.

[0002] A dual-flow turboblower can be defined globally as a gas turbomachine driving a blower module, shrouded or not, composed of either a single blower or two counter-rotating blowers.

[0003] For the sake of clarity, only the term blower will be used here to refer indifferently to either a single blower or a contrarotating doublet.

[0004] In modern turboblowers, the blower module is said to be "reduced" because it is supplemented by a high-power-density speed reducer interposed between the blower and the turbomachine, to optimize their respective rotational speeds and reduce energy consumption. Such a high-power-density speed reducer is herein called a blower reducer, and such a turboblower with a reduced blower module is called a reduced turboblower.

[0005] The cowling, also called a nacelle, which can be schematically represented as a tubular sleeve surrounding the fan, is not mandatory for the operation of a turbofan, but it is nevertheless widely used on current aircraft because it offers numerous advantages, such as the containment of the fan blades and noise, or the isolation and maximization of the fan's propulsive work. The nacelle also provides a volume that allows for the integration of a conventional thrust reversal system by deflecting cold gases, such as the device described in US publication 8109467.This system is used to improve aircraft braking during landing; however, it is known that the fairing, due to its weight and the drag it generates in flight, causes a significant decrease in the engine's propulsive efficiency; this decrease is even greater on modern turbofans with a high bypass ratio and a large fan diameter.

[0006] In cases where the aim is to maximize the propulsive efficiency of a turbofan, one solution is to consider an "open-fan" turbofan, that is, one with a fan module without a shroud, as described, for example, in US publication 2011 286842. This architecture is the most frugal, but apart from some major drawbacks such as the inability to contain a blower blade loss, this solution does not allow the integration of a conventional thrust reversal system into the aircraft engine, as previously described.

[0007] A second solution consists of retaining a fan shroud in order to preserve some of the aforementioned advantages, while seeking to reduce the weight and volume of said shroud as much as possible to minimize its negative impact on the engine's propulsive efficiency. This objective can be achieved with a very thin shroud, but such a thin shroud also does not allow for the integration into the aircraft engine of the conventional thrust reverser system, which requires a shroud of a certain thickness to be accommodated.

[0008] To address this problem, various thrust reversal systems not integrated into the cowling have been proposed in the prior art. One such system, called a "variable-pitch fan," as described, for example, in US publication 3873235, consists of rotating the fan blades around their respective longitudinal axes. By modifying the angular pitch of the fan blades, it is possible to generate thrust in one direction or the other. However, such a thrust reversal system is a complex mechanism that impacts reliability and complicates engine maintenance. Furthermore, if a thin cowling is desired, a large operating clearance between the tips of the fan blades and the cowling is required, which significantly impacts propulsive efficiency during other phases of flight and renders this solution suboptimal.

[0009] A second system has been proposed in the prior art for creating reverse thrust without a shroud. This system, which consists of reversing the direction of rotation of the fan, as described, for example, in publications EP 0940560 or EP 2955359, allows, in addition to better efficiency compared to the conventional system, that the operating clearance between the fan blades and the shroud remains optimal, in cases where a thin shroud is desired. However, for various reasons known to those skilled in the art, in such a high-power aircraft engine application, it is not feasible to reverse the direction of rotation of the operating gas turbomachine to reverse the direction of rotation of the fan. To achieve such a thrust reversal system by reversing the direction of rotation of the fan, it is necessary to use a device which allows, in a reversible and permanent manner, to switch safely and in a sufficiently short time from the normal or nominal operation of the fan, corresponding to the forward movement of the aircraft, to reverse operation, while ensuring a safe and robust power transmission between the turbomachine and the fan during the flight phase.

[0010] The aforementioned prior art systems propose, by means of a clutch and a gear mechanism, such as an epicyclic gearbox, to reverse the direction of rotation of the fan during operation, while maintaining the same nominal direction of rotation of the turbomachine. However, the gearbox(s) of said prior art reversing systems also modify the fan's rotational speed in the nominal direction, which is not optimal.

[0011] Indeed, in order to maximize the reliability of the power transmission between the turbomachine and the fan module during flight, it is desirable that the reversing device allow, in the nominal direction of rotation of the fan, a direct, unreduced, reliable and robust power transmission, in the manner of a simple splined coupling sleeve, i.e. without going through the gears of said reversing reducers.

[0012] Such a direct and non-reduced transmission reversing device also allows, in the case where a blower reducer is desired, the use of such a reducer specifically adapted for this very demanding function.

[0013] Publications FR 3091905 and FR 3114622 propose a similar approach to the aforementioned patents while allowing direct, unreduced drive in the nominal operating direction of the turbofan. However, these systems are neither optimal nor realistic for the application targeted by this application, as such power transmission achieved solely by friction clutches is not feasible for such a high-power turbofan application with very high reliability requirements. Furthermore, disclosures FR 3091905 and FR 3114622 do not permit the use of a geared fan module, which would reduce the aircraft engine's energy consumption, one of the objectives of this application. Description of the invention

[0014] Since the energy performance and reliability of commercial aircraft engines are in constant need of improvement, the objective of the invention is to propose a thrust reversal device by reversing the direction of rotation of the fan of a reduced fan module, solving the problems previously mentioned.

[0015] To this end, the invention relates, according to its most general acceptance, to a thrust reversal device by reversing the direction of rotation of the blower, allowing a blower to switch from a nominal operating mode SI to a reverse operating mode S2, without stopping or reversing the nominal direction of rotation S1 of the turbomachine, by allowing; - A transitional phase of synchronizing the rotational speed of a planetary gearbox carrier, via a multi-disc clutch drum; - A robust and sustainable power transmission between the turbomachine and the geared blower module, outside of the said transient phase.

[0016] Said reversing device comprising a fixed housing; a clutch drum, composed of a cylindrical drum and clutch discs, mounted rotatably around X and axially movable along X; at least one first linear actuator clamping along X, said clutch drum by means of at least one first bearing; a planetary reducer conventionally composed of: a first toothed gear, with axis X, configured to be integral with a low-pressure shaft of said gas turbomachine; a second toothed gear, with axis X, larger than said first toothed gear, configured to be integral with a blower by means of said reduced blower module; a plurality of equally spaced satellites around X, each mounted rotatably around a trunnion, and cooperating simultaneously in mesh with said first toothed gear and said second toothed gear;and a satellite carrier, with axis of rotation X, cooperating with said plurality of satellites via said trunnions attached to it;

[0017] characterized in that said planet carrier, driven in rotation by said clutch drum, is axially mobile along X, independently of the axial displacement of said clutch drum, to allow, after rotational synchronization, a rigid coupling by mesh engagement, with said second toothed gear and / or said first toothed gear by translation of said planet carrier in a first axial direction D, or with said housing by translation of said planet carrier in an opposite axial direction R.

[0018] To achieve this, said planet carrier includes an external toothed ring configured to cooperate with the gear teeth of said second gear. This allows, by translation of the planet carrier in the axial direction D, the interlocking of all the teeth of said external toothed ring of the planet carrier into those of the second gear, and makes it possible to obtain a rotational coupling between the second gear and the planet carrier as rigid as a splined coupling sleeve.Alternatively or in combination, said planet carrier further comprises an internal toothed ring configured to cooperate with the gear teeth of said first gear, thus enabling, during said translation of the planet carrier in the axial direction D, the interlocking of all the teeth of said internal toothed ring of the planet carrier with those of the first gear, thereby enabling a rotational coupling between the first gear and the planet carrier as rigid as a splined coupling sleeve.

[0019] Preferably, the planet carrier comprises both said outer toothed ring and said inner toothed ring, so that the transmission of The power between the turbomachine and the geared fan module is as rigid as a double-spline coupling sleeve, bypassing the planetary gearbox's satellites. This double-spline coupling, bypassing the planetary gearbox's satellites, ensures safe and robust power transmission, particularly during flight.

[0020] In a manner identical to the meshed coupling between the planet carrier and the planetary reducer, said housing has an internal toothed ring configured to cooperate with said external toothed ring of the planet carrier, which allows by translating the planet carrier in the opposite axial direction R, the interlocking of all the teeth of said external toothed ring of the planet carrier, in those of the housing, and allows a rotational coupling between the housing and the planet carrier as rigid as a grooved coupling sleeve. As is known, with the planet carrier rigidly immobilized against rotation in this axial position by the housing attached to the turbomachine stator, the planetary gearbox of the reversing device of the present invention transmits power to the reduced blower module, having a direction of rotation reversed S2 with respect to the direction of rotation SI of the turbomachine.

[0021] At least one, second three-position linear actuator, fixed in translation along X, said planet carrier by means of at least one, second bearing, to allow the movement of said planet carrier in one or the other of said axial direction D or R. Said linear actuator being, for example, a three-position hydraulic annular cylinder.

[0022] Preferably, said clutch drum is fixed in rotation about X, said planet carrier by means of splines. Any other means allowing both rotational drive and free translation about X of the planet carrier would be conceivable.

[0023] Said cylindrical drum has, at mid-length, an inner annular wall, with axis X, comprising two annular friction surfaces extending radially towards its center. The interior of said cylindrical drum is thus divided into two compartments, each comprising a splined inner ring, with axis X, each coupling in rotation a plurality of clutch discs. Said clutch drum therefore encompasses two distinct sets of clutch discs. To complete said sets of clutch discs, said first toothed gear and said housing each comprise a splined ring, with axis X, coupling in rotation a plurality of clutch discs configured to cooperate with and complete said sets of clutch discs.

[0024] Said first actuator, translating the clutch drum in one direction or the other, thus compresses between them one or the other of said disc assemblies of the clutch, either between an annular friction surface of the cylindrical drum and an annular surface of said first toothed gear, or between an annular friction surface of the cylindrical drum and an annular surface of the housing. In doing so, the rotational speed of the clutch drum, and therefore of the planet carrier attached to it, synchronizes respectively, either with that of said first toothed gear driven in rotation by the turbomachine, or with that of the fixed housing, thus stopping the rotating planet carrier.

[0025] Regardless of the axial position of the clutch drum, which either brakes or accelerates the rotational speed of the planet carrier, said second actuator axially translates the planet carrier along the X axis, allowing at least three distinct axial positions: - A first axial position, allowing the planet carrier to be meshed with the second gear and / or the first gear, enabling direct power transmission in a nominal direction of rotation SI, without altering either the direction or the speed of rotation between the turbomachine and the geared blower module. This first axial position of the planet carrier corresponds to the nominal operation of the reversing device of the present invention, corresponding to the forward movement of the apparatus. - A second axial, transitional position, allowing the toothed ring gears of the planet carrier to be disengaged. This second axial transitional position allows the clutch disc assemblies to synchronize the rotational speed of the planet carrier, either with that of the first toothed gear, or to stop its rotation on the housing. - A third axial position, allowing the satellite carrier to be meshed together with the housing, enabling the transmission of power from the turbomachine to the geared blower module, with a reversed direction S2 and a modified rotational speed. This third axial position of the satellite carrier corresponds to the reverse operation of the reversing device of the present invention, corresponding to the thrust reversal phase for braking the aircraft.

[0026] Said first and second actuators are controlled and coordinated by all means guaranteeing the correct operation of the device. Thus, when the thrust reversal is triggered in order to brake the device, the planet carrier is first translated by the second actuator from said first to said second position, then the clutch drum is translated by the first actuator, in the axial direction R, to compress the clutch discs on said annular surface of the housing. The casing engages, causing the clutch drum, and therefore the planet carrier, to brake until it comes to a complete stop. After rotational synchronization with the casing, the planet carrier is moved to the third axial position to transmit the full power required for thrust reversal. The reverse steps are then performed to allow the device to operate in its nominal direction and to transmit the engine's full nominal power via a direct, unmodified, safe, and robust transmission.

[0027] DESCRIPTION OF FIGURES In these drawings: [Fig. 1] is a general schematic view in longitudinal half-section of a first example of the architecture of a geared, double-flow turboblower with a single blower, incorporating a blower reversing device according to the invention. [Fig. 2] is a general schematic view in longitudinal half-section of a second example of the architecture of a geared, double-flow turbofan with counter-rotating fans, incorporating a fan reversing device according to the invention. [Fig. 3] is a schematic view according to Figures 1 and 2, in longitudinal half-section, of a first simplified embodiment of a fan reversing device according to the invention, according to a first direct-drive operating mode. [Fig. 4] is a view according to [Fig. 3], according to a second reverse-drive operating mode. [Fig. 5] is a schematic view according to Figures 1 and 2, in a longitudinal half-section, of a second improved embodiment of a blower reversing device according to the invention, according to a first direct-drive operating mode. [Fig. 6] is a view according to [Fig. 5], according to a third transient operating mode. [Fig.7] is a view according to [Fig.5], according to a second operating mode in reverse drive

[0028] Figures 1 and 2 represent two non-limiting examples of a turboblower or geared turboblower (1) with double flow (A;B), equipped here with a fairing (10), and comprising a reverser (5) as described in the present invention. Fig. 1 represents a first example of a geared turboblower (1) comprising a geared blower module (12) having a single blower (S) driven by a blower reducer (11) and Fig. 2 represents a second example of a geared turboblower (1) comprising a geared blower module (12) having a doublet of counter-rotating blowers (S;S') driven by a blower reducer (H).

[0029] Said geared turboblower (1) comprising from upstream to downstream, in the direction of flow, at least one blower (S), a blower reducer (11), an inverter (5) and a turbomachine (2) comprising a low-pressure compressor (2a), a high-pressure compressor (2b), a combustion chamber (2c), a high-pressure turbine (2d), a low-pressure turbine (2e), and an exhaust nozzle (2f). The high-pressure compressor (2b) and the high-pressure turbine (2d) are connected by a high-pressure shaft (3). The low-pressure compressor (2a) and the low-pressure turbine (2e) are connected by a low-pressure shaft (4).

[0030] At least one blower (S) is driven in rotation by a blower reducer (11) connected to the low pressure shaft (4) of the turbomachine (2) by means of a reverser (5) with coaxial shafts (4a;4b) according to the invention.

[0031] The axes of the high pressure shaft (3), the low pressure shaft (4), the inverter (5), the blower reducer (11) and the blower shaft (6) are substantially coincident with the rotation axis X of the reduced turbo blower (1).

[0032] The inverter (5) is positioned in the front part of the geared turbofan (1). At least one bearing housing (7) is attached to a casing (8) surrounding or enclosing the inverter (5). The casing (8), which can be considered an element of the stator of the turbomachine (2), is attached to the fixed frame of the geared turbofan (1). Optionally, a fan shroud (10) is attached to the fixed frame of the geared turbofan (1), for example, by means of a plurality of profiled spokes (9).

[0033] As schematically shown in Figures 3 and 4,

[0034] The inverter (5) consists overall of two distinct sub-assemblies; a first sub-assembly which can be likened to a planetary type speed reducer, of axis X, well known to those skilled in the art, and a second sub-assembly corresponding to a clutch drum (25), of axis X, movable in translation on X. The said subsets being arranged among themselves and cooperating in the following manner;

[0035] In a first simplified embodiment of the invention, such as a planetary reducer solar gear, a first toothed gear (40) here called "sun", with axis of rotation X and mounted to rotate relative to the fixed frame of the turbomachine (2), comprises a toothed ring (40a), extending longitudinally along X, in meshed engagement and cooperating with a plurality of toothed pinions (30) here called "satellite" equidistributed around the axis X. Each of said satellites (30) is mounted to rotate about a trunnion (52), whose longitudinal axis is parallel to X and radially spaced from it, said trunnions (52) being attached, like a planetary reducer satellite carrier, to an annular wall (50), here called "carrier", extending radially around X, and said carrier (50) being mounted to rotate about X, on at least one bearing (73), connected to the fixed housing (90) of the inverter (5).

[0036] Upstream of the inverter (5), like an outer ring of a planetary reducer, a second toothed gear (60), here called "ring", with axis of rotation X, coaxial with said sun (40) and mounted to rotate relative to the fixed frame of the turbomachine (2), comprises a toothed ring (60a) extending longitudinally along X, encompassing the plurality of satellites (30), being in meshed engagement and cooperating with each of said satellites (30).

[0037] In the present simplified embodiment of the invention, the sun (40), the plurality of satellites (30), the carrier (50), and the ring (60) are fixed in translation, and behave together as a well-known planetary reducer.

[0038] Said sun (40) further comprises a grooved ring (40b), of axis X and extending longitudinally to it, radially smaller than said toothed ring (40a) and coaxial to the latter, cooperating in rotation with a plurality of friction disks (22) free in translation on X, so as to drive the latter, around the axis X, at the same speed and in the same direction of rotation as the sun (40).

[0039] Said sun (40) further comprises an annular wall (40d), of axis X, extending radially to X, attaching together said toothed ring (40a), said grooved ring (40b) and an annular friction surface (40c), of axis X, extending radially to X, coaxially arranged between the toothed ring (40a) and the grooved ring (40b), to be opposite said plurality of friction disc (22).

[0040] Downstream of the inverter (5), a housing casing (90) attached to the fixed frame of the turbomachine (2) by means of the casing (8), includes a grooved ring (90a), with axis X, extending longitudinally to it, and cooperating in rotation with a plurality of friction discs (24) free in translation on X. The housing (90) further comprises an annular friction surface (90c), with axis X extending radially to X, arranged, with said splined ring (90a), in a substantially symmetrical manner, with respect to an annular wall (20e) of a cylindrical drum (20), respectively with said annular friction surface (40c) and splined ring (40b) of the sun (40). An annular wall (90b), with axis X, of the housing (90), extending radially to X, connects said splined ring (90a) and said annular friction surface (90c).

[0041] Said cylindrical drum (20), globally consisting of an annular wall (20g), of axis X, extending longitudinally along X, is rotatably mounted on at least one bearing (72) and is movable in translation in the direction of the axis X. The said cylindrical drum (20) further comprises at mid-length, the said annular wall (20e), of axis X, extending radially at X, from the said annular wall (20g) towards the center of the said cylindrical drum (20), thus dividing the interior of the said cylindrical drum (20) into two compartments.

[0042] Said annular wall (20e) supports two annular friction surfaces (20c;20d), with axis X, coaxial with said annular wall (20e) and symmetrical to each other with respect to the latter, extending radially to X to be opposite said plurality of friction disk (22) and (24).

[0043] Said annular friction surfaces (40c;20d;20c;90c), substantially identical diametrically to said friction discs (22) and (24), are arranged along the X axis, so that said plurality of friction discs (22) is located between said annular friction surfaces (40c) of the sun (40) and (20d) of the cylindrical drum (20); and that said plurality of friction discs (24) is located between said annular friction surfaces (90c) of the housing (90) and (20c) of the cylindrical drum (20).

[0044] The cylindrical drum (20) further comprises, on the inside of said annular wall (20g), two internal grooved rings (20a;20b), with axis X, extending longitudinally along X, and substantially symmetrical to each other with respect to said annular wall (20e). Each of said internal grooved rings (20a;20b) cooperates in rotation with a plurality of friction disks, free in translation about X, respectively (23) and (21), in order to drive the latter around the axis X, at the same speed and in the same direction of rotation as said cylindrical drum (20).

[0045] Said internal grooved rings (20a;20b), radially larger than said grooved ring (40b;90a), respectively of the sun (40) and of the housing casing (90), surround or encompass said plurality of friction disc (21;22) and (23;24).

[0046] Said plurality of friction disc (21;22) and said plurality of friction disc (23;24) are arranged to form two separate clutch assemblies.

[0047] A first upstream clutch assembly consisting of the plurality of friction discs (21) intercalated one after the other with said plurality of friction disc (22), and a second downstream clutch assembly consisting of the plurality of friction discs (23) intercalated one after the other with said plurality of friction disc (24). Said cylindrical drum (20) and said plurality of friction disc (21;22;23;24), thus forming said second clutch drum sub-assembly (25).

[0048] The rotational speed of the clutch drum (25) evolving between zero speed and a speed equal to that of the sun (40), a linear actuator, such as a cylinder (70), preferably, but not limited to, of the hydraulic type, attached to the fixed housing (90), fixed in translation along X, said clutch drum (25) by means of said bearing (72).

[0049] Therefore, when the cylinder (70) exerts a force in the axial direction (D), it, via the bearing (72), displaces the clutch drum (25) along X. The annular friction surface (20d) attached to the cylindrical drum (20) by the annular wall (20e), then compresses said first upstream clutch assembly on the annular friction surface (40c), rotating with the sun (40). In a symmetrical manner, when the cylinder (70) exerts a force in the axial direction (R), opposite to the axial direction (D), the annular friction surface (20c) attached to the cylindrical drum (20) by the annular wall (20e) compresses said second downstream clutch assembly on the annular friction surface (90c), of the fixed housing (90).

[0050] The cylindrical drum (20) further comprises, on the outside of said annular wall (20g), an external grooved ring (20f), with axis X and extending longitudinally along X, cooperating in rotation with a grooved ring (50a) of the carrier (50), allowing the clutch drum (25) movable in translation on X, to be able to drive around the axis X, in the same direction and at the same speed of rotation, the rotating carrier (50), which is fixed in translation in the present simplified embodiment of the invention.

[0051] With reference to [Fig.3], Downstream of the inverter (5), the shaft (4a) of the inverter (5) is connected to the low-pressure shaft (4) of the turbomachine (2), for example, via splines. Thus, the low-pressure shaft (4) drives the rotation and transmits the motive power of the turbomachine (2) to the rotationally mounted shaft (4a). The shaft (4a), coupled in rotation to the sun (40), drives the latter in rotation in one direction (SI), around the X axis, as well as the toothed ring (40a), the splined ring (40b) and the annular friction surface (40c) attached to it.

[0052] In a first operating mode in direct drive of the device according to the invention, corresponding to the forward direction of the aircraft; As described previously, the cylinder (70) exerts a force in the direction (D) to compress the first upstream friction disc clutch assembly (21;22) between said annular friction surfaces (20d) and (40c).

[0053] The compression of said upstream clutch assembly then generates a friction torque progressively coupling in rotation the plurality of discs (21) and (22), and therefore said splined rings (40b) and (20b) cooperating in rotation with the latter, until they rotate together, in the same direction and at the same speed of rotation, around the axis X. The grooved ring (20b) of the cylindrical drum (20), gradually coupling with the grooved ring (40b) of the sun (40), thus drives in the same direction (SI) and up to the same rotational speed as the sun (40), the clutch drum (25) and the carrier (50) constrained in rotation by the latter.

[0054] Said downstream clutch assembly, here uncompressed, is uncoupled, the plurality of friction discs (23) cooperating with the cylindrical drum (20) rotating freely relative to said plurality of friction discs (24), fixed.

[0055] During the coupling phase of the upstream clutch assembly, the plurality of satellites (30), both meshed and cooperating with the sun (40) and at the same time rotatably mounted on said trunnions (52), attached to the carrier (50) driven in rotation around X by the sun (40), adapt their relative rotation speed by also rotating around their respective trunnion (52), until at the end of the coupling phase, that is to say when the carrier (50) is synchronized with the rotation speed of the sun (40), they have a zero rotation speed around their respective trunnion (52).

[0056] Said plurality of satellites (30), cooperating further with the ring (60), therefore progressively drives the latter in the same direction (SI), up to the same rotation speed as the sun (40).

[0057] In this direct drive operating mode of the device, after a coupling phase of the upstream clutch assembly, the sun (40), the clutch drum (25), the carrier (50), the plurality of satellite (30), and the ring (60) then rotate together, as a single piece, around the X axis, in the same direction (SI) and at the same rotational speed.

[0058] The inverter (5) behaves here, according to the said first simplified embodiment of the present invention, as a direct friction coupling, allowing the shaft (4b), attached to the ring (60), to be driven by the shaft (4a) coupled to the turbomachine (2), at the same speed and in the same direction of rotation (SI).

[0059] With reference to [Fig.4], In a second operating mode, the device reverses its drive, corresponding to the direction of thrust reversal to brake the aircraft; The cylinder (70) exerts a force in the axial direction (R), opposite to said axial direction (D), to compress the second downstream friction disc clutch assembly (23);(24), between the annular friction surfaces (20c) and (90c). The compression of said downstream clutch assembly generates a friction torque progressively coupling in rotation the plurality of discs (23) and (24), and therefore said splined rings (20a) and (90a) cooperating in rotation with the latter.

[0060] The grooved ring (20a) of the cylindrical drum (20), gradually coupling with the grooved ring (90a) of the fixed casing (90), progressively immobilizes the clutch drum (25) and the carrier (50) in rotation by the latter. The said upstream clutch, here not compressed, is not coupled, the said plurality of friction disc (22), driven in rotation by the sun (40), in a direction of rotation (SI), rotate freely relative to the said plurality of friction disc (21).

[0061] In a manner symmetrical to the first mode of operation previously described, during the coupling phase of the downstream clutch assembly, said plurality of satellites (30) adapt their relative rotational speed by rotating around their respective trunnion (52), until, at the end of the coupling phase when the carrier (50) is immobilized in rotation, they only rotate on themselves around their respective trunnion (52), like a planetary reducer with a fixed satellite carrier, well known to those skilled in the art, where the ring and the sun rotate in opposite directions to each other.In said second reverse operating mode, said plurality of satellites (30), meshed with the ring (60), progressively drives the ring (60) in one direction (SI), from the first direct drive operating mode, up to a direction (S2), reversed with respect to the direction (SI) of the turbomachine (2), with a rotational speed different from that of the latter, due to the existing gear ratios between the sun, the satellites and the ring.

[0062] In this reverse drive operating mode of the device, after a coupling phase of the downstream clutch assembly, the sun (40) and the ring (60) rotate in opposite directions of rotation, respectively (S1; S2), and at different rotational speeds. The inverter (5) behaves here, according to the said first simplified embodiment of the present invention, as a planetary speed reducer having the planet carrier immobilized in rotation by a friction coupling, allowing the shaft (4b), attached to the ring (60), to be driven by the shaft (4a) coupled to the turbomachine (2), at a different speed and in a direction of rotation (S2), opposite to (SI).

[0063] With reference to figures 5, 6 and 7;

[0064] In order to satisfy the objectives of the present application and to allow, outside of said clutch coupling phase, a safer and more robust power transmission than a simple friction coupling, between the turbomachine (2) and at least one blower (S) of the geared turboblower (1);

[0065] In a second preferred improved embodiment of the invention, the carrier (50) further comprises two toothed rings (50b;50c), with axis X, coaxial, radially spaced from each other and extending longitudinally along X. Said toothed rings (50b;50c), larger than said grooved ring (50a), are arranged to be opposite said toothed ring, respectively, (60a) of the ring (60) and (40a) of the sun (40), so as to be able to mesh and cooperate in rotation with the latter.

[0066] Said second improved embodiment is preferably described here with two toothed crowns (50b;50c), but those skilled in the art will understand that an embodiment not shown here, having a single toothed crown, indifferently (50b) or (50c), would produce a less robust transmission, but having a similar effect to that obtained with the said two toothed rings (50b;50c).

[0067] Furthermore, in said second improved embodiment, the carrier (50) is movable in translation about X, and is held in place by a three-position linear actuator, such as a three-position cylinder (71), preferably, but not exclusively, of the hydraulic type. Said three-position cylinder (71), attached to the fixed housing (90), moves the carrier (50) by means of at least one bearing (73). The housing (90) further comprises a toothed ring (90d), with axis X, extending longitudinally along X, coaxial and larger than the toothed ring (90a). Said toothed ring (90d) is arranged opposite the toothed ring (50b) of the carrier (50), so as to be able to mesh and cooperate in rotation with the latter.

[0068] According to [Fig.5],

[0069] In said first direct drive operating mode, of the present improved embodiment of the invention;

[0070] after said coupling phase of the upstream clutch assembly, as described previously in the simplified embodiment;

[0071] the sun (40), the carrier (50), the plurality of satellites (30) and the ring (60) rotating together in the same direction (SI) and at the same rotational speed;

[0072] The carrier (50) is translated along X by said three-position cylinder (71) into a first position (71a) to engage in meshed grip and couple in rotation, at the same time, the toothed ring (40a) of the sun (40) with the toothed ring (50c) of the carrier (50) and at the same time, the toothed ring (60a) of the ring (60) with the toothed ring (50b) of the carrier (50).

[0073] In this direct drive operating mode according to the present embodiment of the invention, the carrier (50) directly coupling in rotation the sun (40) and the ring (60), like a double-grooved sleeve, the driving power transmitted to the shaft (4a) by the turbomachine (2), is therefore directly transmitted from the sun (40) to the ring (60), via the two toothed rings (50b;50c) of the carrier (50), without passing either through the meshes of the plurality of satellites (30), or through the friction discs (21;22) of said upstream clutch, thus ensuring a direct, safe and robust transmission between the turbomachine (2) and at least one blower (S) of the turboblower (1), rotating together in the same direction (SI) and at the same rotational speed.

[0074] According to figure (7),

[0075] In said second mode of operation in reverse drive, of the present improved embodiment of the invention;

[0076] after said coupling phase of the downstream clutch assembly, as described previously in the simplified embodiment;

[0077] the sun (40) and the ring (60) rotating in opposite directions of rotation, respectively (S1;S2), at different rotation speeds and the carrier (50) being immobilized in rotation relative to the fixed casing (90);

[0078] The carrier (50) is translated by the three-position cylinder (71) into a third position (71c) to engage in meshed grip and couple in rotation the toothed ring (50b) of the carrier (50) with the toothed ring (90d) of the housing (90).

[0079] In this reverse drive operating mode according to the present embodiment of the invention, the motive power transmitted to the shaft (4a) by the turbomachine (2) is therefore transmitted from the sun (40) to the ring (60), via said plurality of satellites (30) rotating on themselves, like a known planetary speed reducer, the carrier (50) being immobilized in rotation directly by the casing (90), without passing through the friction discs (23;24) of said downstream clutch, thus ensuring a safe and robust transmission between the turbomachine (2) and at least one blower (S) of the geared turboblower (1), rotating at a different speed and in a direction of rotation (S2), opposite to (SI).

[0080] According to [Fig.6],

[0081] A third transient operating mode is represented, where, before piloting the cylinder (70) in either axial direction (D) or (R), the carrier (50) is translated to a second position (71b) of the three-position cylinder (71), to separate the meshed grips of said first direct operating mode, or of said second reverse operating mode, while awaiting the synchronization of said coupling phase of said upstream clutch assembly or said downstream clutch assembly, before being translated again to a position (71a) or (71c), as previously described in said first direct drive operating mode or said second reverse drive operating mode, of the present embodiment of the invention.

[0082] The inverter (5) as described in the present invention therefore allows, on the one hand; A direct drive operating mode where the turbomachine (2) drives the shaft (4b) of the inverter (5), at the same speed and in the same direction of rotation (SI), and a reverse drive operating mode where the turbomachine (2) drives the shaft (4b) of the inverter (5), in a direction of rotation (S2), opposite to (SI); On the other hand, allows the direction of rotation of the shaft (4b) of the inverter (5) to evolve, during said transient coupling phases, from a direction of rotation (SI) to a reversed direction of rotation (S2), in a progressive and reversible manner; And finally allows, outside of the aforementioned coupling or clutching phases, a safe and robust transmission of power in meshed taps, between the shafts (4a) and (4b) of the inverter (5).

[0083] Such a thrust reverser device with a clutch drum and movable planet carrier, dedicated solely to reversing the direction of rotation of an operating fan, as described by the present invention, makes it possible to take significant advantage of the reduced inertia of the fan generated by the fan reduction gear of the reduced fan module. This allows for a realistic number and diameter of friction discs, compatible with the materials, cooling, high sliding speeds, reaction times, and high power of the intended application, while reliably and permanently accepting the significant axial play generated by the cumulative wear of the discs over the service life of such an aircraft turbofan.

[0084] In addition to a significant weight and drag reduction provided by the replacement, by the present invention, of conventional cold gas deflection thrust reversers, another advantage of the present device is that it also allows greater efficiency of the aircraft's thrust reversal, achieved directly by the fan itself, such as for example increasing the time of use of thrust reversal on landing, the engine being less sensitive to FOD.

Claims

1. Demands Thrust reversing device (5) with planetary reduction gear, by reversing the direction of rotation of a blower (S) in operation, in particular for a geared turbo blower (1) with longitudinal axis X composed of a gas turbomachine (2) driving a geared blower module (12) via said reversing device (5); said reversing device (5) comprising: - a fixed (90) casing; - a clutch drum (25), consisting of a cylindrical drum (20) and clutch discs (21;22;23;24), mounted to rotate around X and movable axially along X; - at least one, first linear actuator (70) binding according to X, said clutch drum (25) by means of at least one, first bearing (72); - a planetary reducer composed classically of: of a first toothed gear (40), of axis X, configured to be integral with a low pressure shaft (4) of said gas turbomachine (2); of a second toothed gear (60), of axis X, larger than said first toothed gear (40), configured to be integral with a blower (S) by means of said reduced blower module (12); of a plurality of satellites (30) equally distributed around X, each mounted rotatably around a trunnion (52), and cooperating simultaneously in meshing with said first toothed gear (40) and said second toothed gear (60); and of a satellite carrier (50), with axis of rotation X, cooperating with said plurality of satellites (30) through said trunnions (52) attached to it; characterized in that said planet carrier (50), driven in rotation by said clutch drum (25), is axially mobile along X, independently of the axial displacement of said clutch drum (25), to allow, after rotational synchronization, a rigid coupling by mesh engagement with said second toothed gear (60) and / or said first toothed gear (40) by translation of said planet carrier (50) in a first axial direction (D), or with said housing casing (90) by translation of said satellite carrier (50) in an opposite axial direction (R).

2. Reversing device (5) according to claim 1, characterized in that said planet carrier (50) comprises an external toothed ring (50b) configured to cooperate with the gear teeth (60a) of said second toothed gear (60), allowing after interlocking of the links into each other, by axial translation of said planet carrier (50), a rigid rotational coupling between the planet carrier (50) and said second toothed gear (60).

3. Reversing device (5) according to the preceding claims, characterized in that, in alternative or combination, said planet carrier (50) comprises an internal toothed ring (50c) configured to cooperate with the gear teeth (40a) of said first toothed gear (40), allowing after interlocking of the links into each other, by axial translation of said planet carrier (50), a rigid rotational coupling between said planet carrier (50) and said first toothed gear (40).

4. Reversing device (5) according to the preceding claims, characterized in that said housing (90) has an internal toothed ring (90d) configured to cooperate with said external toothed ring (50b) of said planet carrier (50), allowing after interlocking of the links into each other, by axial translation of said planet carrier (50), a rigid rotational coupling between the planet carrier (50) and said housing (90).

5. Reversing device (5) according to the preceding claims, characterized in that said planet carrier (50) is fixed in rotation around X by said clutch drum (25), by means of splines (20f;50a) or any other means allowing both a rotational drive and a free translation along X.

6. Reversing device (5) according to the preceding claims, characterized in that said cylindrical drum (20) has at mid-length, an inner annular wall (20e) comprising two annular surfaces (20d;20c), of axis X, extending radially towards its center, separating two inner grooved rings (20b;20a) of axis X, each coupling in rotation a plurality of clutch discs (21;23).

7. Reversing device (5) according to the preceding claims, characterized in that said first toothed gear (40) and said housing (90) each comprise, symmetrically to said wall (20e), a splined ring of axis X (40b;90a), respectively coupling in rotation, a first plurality of clutch disc (22), and a second plurality of clutch disc (24), configured to cooperate by clutching, with said plurality of clutch disc (21;23) being associated with them.

8. Reversing device (5) according to the preceding claims, characterized in that said clutch disc assemblies (21;22) and (23;24), alternately compressed by said first actuator (70) between said annular surface (20d;20c) of the cylindrical drum (20), and annular surfaces (40c;90c) of the first toothed gear (40), or of the housing (90), synchronize the planet carrier (50) to the rotational speed of said first toothed gear (40), or stop it on said housing (90).

9. Reversing device (5) according to the preceding claims, characterized in that, a second three-position linear actuator (71) translates on X, via a second bearing (73), said planet carrier (50), to a position (71a) allowing direct power transmission in the nominal direction (SI), or to a transient position (71b) disengaging said toothed rings (50b;50c) of the planet carrier (50) from all meshed grips, or to a position (71c) allowing power transmission in the reverse direction (S2).

10. Reversing device (5) according to the preceding claims, characterized in that said first and second actuator (70;71) are coordinated by any means guaranteeing the operation of the device, in particular by ensuring, via said transient position, that the engagement of said meshed interlocks occurs only after synchronization of the appropriate rotation speed of said satellite carrier (50).

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