Counter-rotating blower module with high power density radial gearbox for turbo blower

Abstract

The invention relates to a counter-rotating fan module for equipping a turbofan (10) and cooperating with a gas turbomachine (2), the module being designed to be arranged axially upstream of a low-pressure compressor (2a). The module comprises, from upstream to downstream, a first fan (S), a counter-rotating radial reduction unit (50), and a second fan (S'). The reduction unit comprises a radial gearbox (5) with coaxial shafts (X) and intersecting axes, formed of three sub-assemblies (SE1, SE2, SE2') comprising a sun wheel (21) and a plurality of planet gears (22) cooperating simultaneously with two ring gears (30, 300) attached respectively to fan shafts (6, 60) driving the fans (S, S').A module support (80) ensures the attachment of the central hub (20a) of a planet carrier (20) to a housing (8) which can be considered as an element of the stator, so as to make the planet carrier fixed relative to said housing, the reduction unit being positioned in the front part of the turboblower. "Figure for abbreviation: Figure (2)".

Description

Title of the invention: High power density radial geared counter-rotating blower module for turbo blower

[0001] The present invention relates to the field of speed reducers for aircraft gas turbine engines, in particular for turbofans with a high bypass ratio.

[0002] A turbofan (or "turbofan") can be broadly defined as a gas turbomachine driving at least one enclosed fan (or "fan") of a fan module. Newer generations of turbofans with high bypass ratios include a mechanical speed reducer coaxially connected between the turbomachine output shaft and the fan shaft. Typically, the purpose of the speed reducer is to transform the high rotational speed of the turbomachine shaft into a slower rotational speed for the fan-driving shaft, thereby optimizing the turbomachine's rotational speed while maintaining a suitable fan speed. This allows, among other things, for increased propulsive efficiency and a reduction in engine noise.

[0003] For such a turboblower, with longitudinal axis of rotation X, it is known that the greater the power density the reducer allows (power transmissible by the reducer divided by its weight), as well as a high reduction ratio, the more efficient it is. However, an aircraft engine is an environment where operating conditions and reliability requirements are extremely severe, and in such a turbofan with a reduction gear, the highly stressed gear teeth are among the most sensitive mechanical parts of the engine.

[0004] To improve the reliability of such a turboblower reducer, it is advantageous to use a coaxial shaft reducer with intersecting axis gears, i.e. a reducer composed of a pair of toothed wheels coaxial to the axis of rotation X of the turboblower, connected by a plurality of toothed pinions whose axes of rotation are substantially transverse to the longitudinal axis of rotation X of the motor. This "radial" orientation of the toothed gears relative to the X axis of rotation of the motor allows the gear meshes to be much less sensitive to structural deflections of the turboblower, and therefore allows for improved reliability.

[0005] A high power density radial gearbox for turbo blowers is known from the international publication WO2021 245180 Al, which makes it possible to obtain both a reduction ratio and optimized power density, corresponding to the needs of current turboblowers. The aforementioned radial gear reducer with intersecting axes of the aforementioned patent is a "split torque" type reducer composed of a plurality of internal force paths which divides the torque and allows a maximized power density. To achieve this, the plurality of force paths, consisting of pairs of rotationally coupled toothed gears, also called satellites, with axis of rotation Y, are equidistant substantially transversely with respect to the axis of rotation X of the turbofan.

[0006] An advantage afforded by said high power density radial reducer is the transverse orientation of said satellites with respect to the axis of rotation X of the turbomachine. Indeed, this gear mesh orientation allows the gearbox to operate on the non-rigid shaft line of a turbofan, due to the possible misalignments of the rotation axes of the various rotating parts constituting said shaft line. Therefore, the radial gearbox does not necessarily need to be flexibly or "floating" attached to the fixed motor frame to compensate for these misalignments.

[0007] As specified in patent WO2021 245180 Al, another advantage permitted by said radial reducer is the possibility of said satellites being able to drive in rotation either a single blower, as detailed in a particular mode of the invention in provisional national application FR2203341, or to drive simultaneously two blowers in counter-rotation.

[0008] It is known to those skilled in the art that a pair of counter-rotating fans provides greater propulsion efficiency than a single fan rotating in one direction. Therefore, given the current strong trend towards the development of highly efficient aircraft engines, it is advantageous for a turbofan gearbox that optimizes the turbomachine's speed to also drive such counter-rotating fans in the most reliable way possible.

[0009] Therefore, a module of counter-rotating blowers driven in rotation by the radial reducer of patent WO2021 245180 Al must be proposed, as well as an example of attaching said module to a gas turbomachine of an aircraft engine.

[0010] 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 variant of the use of the radial reducer of the aforementioned patent, in which said reducer drives in rotation two counter-rotating fans, in a fan module that can be used in a dual-flow turbofan, as well as an example of attaching said module to a gas turbomachine of an aircraft engine.

[0011] To this end, the invention relates, in its most general sense, to a counter-rotating blower module for a turbofan, comprising two blowers driven in counter-rotation by a radial reducer according to the international publication WO2021 245180 Al, and the integration or incorporation of such a blower module into a turbofan, for the purpose of transferring the propulsion of said doublet of counter-rotating blowers to an aircraft.

[0012] DESCRIPTION OF FIGURES In these drawings: - [Fig. 1] is a general view in longitudinal half-section of an example of the architecture of a dual-flow turboblower, incorporating a counter-rotating blower module according to the invention - [Fig.2] is a detailed front view according to [Fig.1] - [Fig.3] is an exploded isometric detail view of a sub-assembly of the radial reducer according to [Fig.1] - [Fig.4] is an exploded isometric view of a counter-rotating radial reduction group of a blower module according to [Fig.1] - [Fig. 5] is a detailed front view in a longitudinal half-section of the counter-rotating blower module according to the invention

[0013] Figure (1) shows the counter-rotating fan-assisted turbofan (10) according to the invention, which comprises, from upstream to downstream in the flow direction (A; B), a fan shroud (9b) encircling a counter-rotating fan module comprising a first fan S, a counter-rotating radial reduction unit (50), herein referred to as "PGB-CR", and a second fan S'; 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).

[0014] The two blowers S and S' are driven in counter-rotation respectively by blower shafts (6) and (60), connected to the low pressure shaft (4) of the turbomachine (2) by means of a radial reducer (5) with coaxial shafts according to patent WO2021245180A1. The axes of the high-pressure shaft (3), the low-pressure shaft (4) and the blower shafts (6) and (60) are substantially coincident with the rotation axis X of the turbo blower (10).

[0015] The PGB-CR (50) is positioned in the front part of the turbo blower (10). A module support (80), incorporated into the PGB-CR (50), is attached to a housing (8) comparable to an element of the stator of the turboblower (10). Said casing (8) is attached by means of a plurality of profiled radii (9), to the fan shroud 9b corresponding to a fixed frame of the turboblower (10).

[0016] As illustrated in Figures 4 and 5, The said PGB-CR (50) is composed of six distinct sub-assemblies, from upstream to downstream, an upstream blower bearing support (7), sub-assemblies SE2, SE1 and SE2', a downstream blower bearing support (70), and a module support (80). The said subassemblies SE1, SE2 and SE2' together form the said radial reducer (5). The said upstream blower bearing supports (7) and downstream blower bearing supports (70) integrate or incorporate the said subassemblies SE1, SE2 and SE2' of the radial reducer (5), so as to substantially encompass the said radial reducer (5).

[0017] As illustrated in Figures 2, 3 and 4, Downstream of the radial reducer (5), the shaft (4b) of sub-assembly SE1 of the radial reducer (5) is connected to a flexible sleeve (4a), for example via splines (4bl). Thus, the low-pressure shaft (4), coupled to the flexible sleeve (4a), drives and transmits the motive power of the turbomachine (2) to the shaft (4b) of the radial reducer (5), which is rotatably mounted on a bearing support (4c) via, for example, a spherical bearing (4c 1), or, in another embodiment not shown, a pair of ball bearings. The shaft (4b) drives in rotation around the X axis, a first toothed wheel (21) here called "sun wheel", by means, for example, of splines (4b2) in contact with a rim (21a) attached, for example, by a plurality of screws to the sun wheel (21).

[0018] The solar wheel (21), located preferably in the present example, but not exclusively, on the upstream side of the radial reducer (5), is meshed and cooperates with a plurality of toothed pinion (22b;22b'), here called "internal satellite", for example, ten internal satellites (22b;22b'), each having their respective axis of rotation Y equidistant around the axis of rotation X of the turboblower, transverse to it.

[0019] In the present example, but not limited to it, said axes of rotation Y are perpendicular to the axis of rotation X of the turboblower. The said internal satellite (22b; 22b') furthermore forming an integral part of pairs of toothed gears (22) herein referred to as "satellites". Each of said satellites (22) being composed of an internal satellite (22b) or (22b') and a flexible coupling (22c), coupling in rotation a second toothed gear (22a) herein referred to as "external satellite".

[0020] In the present example, but not limited to, said pinions and gears are spiral bevel gear pairs. Said solar wheel (21) driven by the shaft (4b), drives in rotation said internal satellite (22b;22b') which in turn drive in rotation said external satellite (22a) by means of said coupling (22c).

[0021] The plurality of satellites (22) are held in their respective positions by a satellite carrier (20) consisting of a central hub (20a), to which are attached as many trunnions (20b) as there are satellites (22), i.e., in this example, ten trunnions (20b). Each of said trunnions (20b) is arranged so that each of said satellites (22) pivots substantially coaxially about a trunnion (20b). The axes of revolution of said trunnions (20b) are therefore coincident with the axes of rotation Y of the satellites (22).

[0022] On an end proximal to the axis X, the trunnions (20b) are attached to the central hub (20a) and extend radially in order to be attached, on their distal end, to an outer annular ring of said satellite carrier (20), encompassing the plurality of satellite (22).

[0023] Said outer annular ring further comprising two circular flat faces (201) and (202) extending radially, coaxial with the X axis, parallel and symmetrical to each other with respect to a median plane passing through the rotation axes Y of said plurality of satellite (22); Two cylindrical walls (204) and (203), coaxial with the X axis, encompassing said plurality of toothed pinion (22a), and extending longitudinally symmetrically with respect to said median plane, from said circular plane faces (201) and (202) respectively; The said outer annular band further comprising, in addition, perforations for screw passages, passing through said circular flat faces (201) and (202).

[0024] On [Fig.4], we can see the subset SE2 and the subset SE2', substantially symmetric with respect to the aforementioned median plane described above, and therefore with respect to the rotation axes Y of the plurality of toothed gear (22a). The said sub-assembly SE2 is globally composed of a second toothed wheel (30), here called "crown", attached to the blower shaft (6). The said SE2' sub-assembly is globally composed of a third toothed wheel (300), here called "CR crown", attached to the blower shaft (60).

[0025] With reference to figures (4) and (5), in order to incorporate said radial reducer (5) between said upstream blower bearing supports (7) and downstream blower bearing supports (70), said subassemblies SE2 and SE2' of the radial reducer (5) are respectively mounted rotatably on the pair of bearings (7a) and (7b), and on the pair of bearings (70a) and (70b). The bearings in question are preferably, but not exclusively, of the tapered roller type arranged head-to-tail for the intended application. Other mountings Bearings not shown but well known to the skilled man could be used such as, for example, a pair of ball bearings or a ball bearing combined with a roller bearing.

[0026] Furthermore, in order to connect together the fixed parts of said PGB-CR (50), namely said upstream blower bearing support (7) and downstream blower bearing support (70), with said planet carrier (20) of subassembly SE1; The upstream blower bearing support (7) includes, among other things, a cylindrical wall (73), with axis of revolution X, encompassing the subassembly SE2 and extending longitudinally, up to a circular flat face (72) having holes for screw passage, and orthogonal to said cylindrical wall (73), so that when said circular flat face (72) and (202) are coplanar with each other, and said cylindrical wall (73) and (203) are coaxial with each other, the plurality of said toothed pinion (22a) of the satellites (22) of the subassembly SE1 mesh and cooperate with said ring (30) of the subassembly SE2, the axes of rotation of the shaft (4b) and the blower shaft (6) of the subassembly SE2 being substantially coincident.

[0027] The two sub-assemblies SE1 and SE2 meshed and cooperating together operationally thus form a first upstream part of the radial reducer (5) integrated or incorporated into the upstream blower bearing support (7).

[0028] The downstream blower bearing support (70) includes, among other things, a cylindrical wall (703), with axis of revolution X, encompassing the subassembly SE2' and extending longitudinally to a circular flat face (702) having holes for screw passage, and orthogonal to said cylindrical wall (703), so that when said circular flat face (702) and (201) are coplanar with each other, and said cylindrical wall (703) and (204) are coaxial with each other, the plurality of said toothed pinion (22a) of the satellites (22) of the subassembly SE1 mesh and cooperate with said ring CR (300) of the subassembly SE2', the axes of rotation of the shaft (4b) and the blower shaft (60) of the subassembly SE2' being substantially coincident.

[0029] The two sub-assemblies SE1 and SE2' meshed and cooperating together operationally thus form a second downstream part of the radial reducer (5) integrated or incorporated into the downstream blower bearing support (70).

[0030] A plurality of screws (41), of which only a part is shown for clarity, passing through said screw passages, the annular wall (72) of the upstream blower bearing support (7), said outer annular ring of the planet carrier (20) of subassembly SE1, and the annular wall (702) of the downstream blower bearing support (70), connects said fixed parts of the PGB-CR (50).

[0031] Furthermore, in order to attach said fixed parts of the PGB-CR (50) to the stator of the turboblower (10), a module support (80), with axis of revolution X, composed overall of a cylindrical wall (80b) and a conical wall (80a) flaring radially from said cylindrical wall (80b) towards said housing (8), is attached to the housing (8), for example, by a plurality of screws (82), and is attached in the upstream part, to the central hub (20a) of the satellite carrier (20), for example, by a plurality of screws (81) and splines (20al) and (80bl) cooperating with each other.

[0032] In the downstream part of said PGB-CR (50), the downstream blower bearing support (70) incorporates a bearing (70c), in order to allow a transfer of forces between the downstream blower bearing support (70) and the module support (80), passing through the blower shaft (60), mounted rotatably. The said bearing (70c) is preferably, but not exclusively, a single ball bearing for the intended application. Other bearing arrangements not shown but well known to those skilled in the art could be used, such as, for example, a pair of ball bearings, a ball bearing combined with a roller bearing, or two tapered roller bearings mounted back-to-back.

[0033] As a result, when the solar wheel (21) of the radial reducer (5) is set in rotation by the turbomachine (2), it drives in rotation the plurality of satellites (22), consisting among other things of said toothed pinion (22a), each rotating around their respective trunnions (20b), of axis Y, said trunnions (20b) being held in their position by said satellite carrier (20), fixed with respect to the stator of the turboblower (10). Said toothed pinion (22a), meshed and cooperating on an upstream side with the ring (30) and meshed and cooperating simultaneously on a downstream side with the ring CR (300), simultaneously drive in rotation, around the X axis of the turboblower, the ring (30) and the ring CR (300), one in a direction of rotation opposite to the other.

[0034] Reduction ratios existing between the different gears (21);(22b);(22b'); (22a);(30) or (300), of the radial reducer (5), cause the ring (30) and the ring CR (300) to rotate at a slower rotational speed than the rotational speed of the shaft (4b).

[0035] Depending on the more or less transverse orientation angle of the Y rotation axes of the satellites (22), relative to the X axis of the turbofan, the rotational speed of the ring (30) and the CR ring (300) may be identical or different. In the case of the present example, where the Y rotation axes are substantially perpendicular to the X rotation axis of the turbofan, the rotational speed of the ring (30) and the CR ring (300) are substantially identical. The said ring (30) and ring CR (300) being coupled respectively to the blowers S and S', the latter are driven simultaneously in counter-rotation with respect to each other, at a rotational speed slower than the rotational speed of the turbomachine (2).

[0036] Numerous advantages are provided by such an aircraft engine incorporating a counter-rotating fan module reduced according to the present invention, including a substantial gain in propulsive efficiency, compactness and increased reliability of the counter-rotating reducer, provided by the fact that many forces oppose and cancel each other out, thus limiting the loads on the internal components of said counter-rotating reducer.

Claims

1. Demands Counter-rotating blower module, X-axis, for turboblower (10), said module being configured to cooperate with a gas turbomachine (2) with a longitudinal axis coinciding with said axis (X), and intended to be arranged axially upstream of said turbomachine (2) comprising a low-pressure compressor (2a), said counter-rotating blower module comprising, from upstream to downstream: - a first blower (S), a counter-rotating radial reducing group (50), and a second blower (S'); - said counter-rotating radial reduction group (50) comprising a module support (80) and a radial speed reducer (5), with coaxial shafts of X axis, with gears with intersecting axes, formed of three sub-assemblies SE1, SE2 and SE2'; - said sub-assembly SE2 being globally composed of a ring (30) mounted to rotate around the X axis, coaxial and integral with a blower shaft (6) connected to said blower (S); - said subassembly SE2' being globally composed of a CR ring (300) mounted to rotate about the X axis, coaxial and integral with a blower shaft (60) connected to said blower (S'); - said subassembly SE1 comprising, among other things, a solar wheel (21), of axis (X), configured to transmit the motive power of said gas turbomachine (2), and a plurality of satellites (22) equally distributed about the axis (X), of rotation axis (Y) transverse to said axis (X), cooperating simultaneously in mesh mesh with said ring (30) and said CR ring (300), said plurality of satellites (22) being mounted to rotate on a satellite carrier (20) comprising a central hub (20a); characterized in that said blowers (S) and (S') are arranged on either side of said radial reducer (5), respectively upstream and downstream, and in that said module support (80) is configured to attach said central hub (20a) of the planet carrier (20) to a housing (8) belonging to a fixed structure of the turbo blower (10), so as to make said planet carrier (20) fixed relative to said housing (8), said counter-rotating radial reduction unit (50) being intended to be positioned in the front part of the turbo blower (10).

2. Blower module according to claim 1, characterized in that said satellite carrier (20) is composed of a central hub (20a), of axis X, on which are attached a plurality of trunnions (20b), of axis Y transverse to the axis X, extending radially in order to be attached, on their distal end to the axis X, to an external annular ring of said satellite carrier (20), encompassing the plurality of said satellites (22).

3. Blower module according to any one of claims 1 and 2, characterized in that said support module (80), of axis of revolution (X), is composed of a cylindrical wall (80b) and a conical wall (80a) flaring radially from said cylindrical wall (80b), and is configured to be attached to a housing (8) of the turbo blower (10).

4. Blower module according to any one of claims 1 to 3, characterized in that said module support (80) is attached, in its upstream part, to said central hub (20a) of the planet carrier (20) by splines (20a 1 ; 80b 1) and / or by a plurality of screws (81), so as to make said planet carrier (20) fixed relative to a housing (8) belonging to a fixed structure of the turboblower (10).

5. Blower module according to any one of claims 1 to 4, characterized in that it comprises a shaft (4b) integral with the solar wheel (21), mounted rotatably about the axis (X), and configured to receive and transmit motive power to said solar wheel (21), the latter rotating said plurality of satellites (22).

6. Blower module according to any one of claims 1 to 5, characterized in that each satellite (22), with axis of rotation (Y), consists of a pair of rotationally coupled conical gears, comprising an inner gear (22b, 22b') cooperating in mesh engagement with the sun wheel (21), and an outer gear (22a) cooperating in mesh engagement with the rings (30) and (300), so that each satellite (22) cooperates simultaneously with the sun wheel (21) and the two rings (30, 300).

7. A blower module according to any one of claims 1 to 6, characterized in that an upstream blower bearing support (7) incorporates said SE2 subassembly rotatably mounted about the X-axis, such that said ring (30) meshes with said plurality of gears (22a) to form a first upstream part of said radial reducer (5) incorporated into the counter-rotating radial reducer group (50).

8. Blower module according to any one of claims 1 to 7, characterized in that a downstream blower bearing support (70) incorporates said SE2' subassembly rotatably mounted about the X axis, so that said CR ring (300) cooperates in mesh mesh with said plurality of toothed gears (22a), to form a second downstream part of said radial reducer (5) incorporated into the counter-rotating radial reducer group (50).

9. Blower module according to claims 2, 4, 7 and 8, characterized in that said upstream blower bearing support (7) and downstream blower bearing support (70) are attached to said outer annular ring of the planet carrier (20) by a plurality of screws (41).

10. Blower module according to claim 8, characterized in that the downstream blower bearing support (70) incorporates a bearing (70c) configured to transmit forces between said downstream blower bearing support (70) and the module support (80), via the blower shaft (60) integral with the ring (300).

11. Blower module according to any one of claims 1 to 10, characterized in that the blower (S) coupled to the ring (30) and the blower (S') coupled to the ring CR (300) rotate in contra-rotation with respect to each other, at a rotational speed slower than the rotational speed of the shaft (4b) integral with the sun wheel (21).

12. Blower module according to any one of claims 1 to 11, characterized in that the blowers (S, S') rotate in counter-rotation with each other at substantially identical rotational speed only when the axes (Y) of the satellites (22) are substantially perpendicular to the axis (X).

13. Turbofan (10) comprising, from upstream to downstream in the flow direction, a fan shroud (9b) encircling a counter-rotating fan module according to any one of claims 1 to 12, and a gas turbomachine (2) disposed downstream of said module, said turbomachine (2) comprising a low-pressure compressor (2a), said module being disposed axially upstream of said low-pressure compressor (2a), said counter-rotating radial reduction unit (50) of the module being positioned in the front portion of the turboblower (10), the module support (80) being attached to a housing (8) belonging to a fixed structure of the turboblower (10), said housing (8) being attached to the blower fairing (9b) by means of a plurality of profiled radii (9).

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