Speed reducer for driving a turbine-engine fan

Abstract

The invention relates to a speed reducer (100) for driving a turbine-engine fan, comprising a sun gear (110), a ring gear (120), planet gears (130), and a planet carrier, the sun gear being configured to be mechanically connected to a turbine-engine turbine in order to be rotated by the latter, and the ring gear or the planet carrier being configured to be mechanically connected to a turbine-engine fan in order to rotate the latter; the planet gears are arranged as N stages of planet gears arranged between the sun gear and the ring gear, N being an even number, a first of said stages having its planet gears meshing with the sun gear and a last of said stages having its planet gears meshing with the ring gear, and, for the planet gears of an nth stage and an n+1th stage that are directly consecutive, with n ranging from 1 to N-1, each planet gear of the nth stage meshing with a planet gear of the n+1th stage.

Description

[0001] Description

[0002] Title: Speed ​​reducer for driving a turbomachine blower

[0003] Scope of the invention

[0004] The present invention relates to the field of aeronautics, and more specifically, to aircraft turbomachinery.

[0005] More specifically, the invention relates to a speed reducer for driving a turbomachine blower.

[0006] The invention also relates to a turbomachine, in particular a turbojet with an unfaired fan, comprising such a speed reducer.

[0007] The invention further relates to a set of turbomachines, one of which includes such a speed reducer, as well as an aircraft comprising such a set of turbomachines.

[0008] Prior art

[0009] It is known to use speed reducers to lower the rotational speed of a turbomachine shaft, particularly a low-pressure shaft of a turbojet engine, to drive a turbomachine fan at a reduced speed. This application is especially important for turbomachinery with a high bypass ratio, particularly those with very high bypass ratios.

[0010] In particular, we know of the technique of so-called planetary type speed reducers, which allow for high transmission ratios while being particularly compact.

[0011] A planetary gearbox typically consists of a gear set comprising a central pinion, called the sun gear, a peripheral gear, usually with internal teeth, called the ring gear, and a plurality of pinions arranged between the sun gear and the ring gear, called planet gears. In addition, such a gearbox includes a planet carrier on which the planet gears are mounted.

[0012] When used to reduce the rotational speed of one rotating element relative to another, such a speed reducer is connected at the input to a driving rotating element, which here is in particular a turbine, via its solar element, and connected at the output to a driven rotating element, which here is in particular a blower, via its ring gear or planet carrier.

[0013] A speed reducer connected at the output by the ring gear, with the planet carrier fixed in rotation (for example, attached to a turbine housing), is generally called a planetary gearbox. Conversely, a speed reducer connected at the output by the ring gear, with the ring gear fixed in rotation (for example, attached to a turbine housing), is generally called an epicyclic gearbox. The output of the speed reducer rotates in one direction or the other relative to the input direction of rotation, depending on the type of connection. Speed ​​reducers can also be of the differential type, meaning that no component is fixed in rotation.

[0014] We know, for example, from patent EP 3596360 B1, of a speed reducer for the rotational drive of a turbomachine blower, the speed reducer being in particular of the epicyclic type, with the blower rotating in the same direction as the turbine.

[0015] There is a need for a simple and convenient solution to adapt the direction of rotation of a turbomachine blower whose turbine rotates in a predetermined direction.

[0016] Description of the invention

[0017] The present invention aims to remedy all or part of the drawbacks of the prior art mentioned above.

[0018] The invention relates, according to a first aspect, to a speed reducer for driving a turbomachine fan, the speed reducer comprising a solar element, a ring, a plurality of satellites, and a satellite carrier supporting said satellites, the solar element being configured to be mechanically connected to a turbomachine turbine to be driven into rotation by it, and at least one of the ring or the satellite carrier being configured to be mechanically connected to a turbomachine fan to drive into rotation the latter, and in which speed reducer: the satellites are arranged according to / V stages of satellites disposed between the solar element and the ring, / V being even and preferably equal to 2, each nth stage, n going from 1 to N, comprising at least two satellites;a first of said stages, for which n=l, each having its satellites meshing with the solar and a last of said stages, for which n=N, each having its satellites meshing with the corona; and in that, for the satellites of an nth and an n+1th stage directly consecutive, n going from 1 to A / -1, each satellite of the nth stage meshes with a satellite of the n+1st stage.;

[0019] Thus, the speed reducer according to the invention makes it possible to drive a turbomachine fan in rotation either in the same direction of rotation as the turbomachine turbine, when the fan is connected to the ring, or in the opposite direction of rotation to that of the turbomachine turbine, when the fan is connected to the satellite carrier.

[0020] Such a speed reducer is particularly compact, and can be integrated into a turbomachine under conditions similar or identical to those of a speed reducer known in the art.

[0021] In particular, depending on the requirements, a turbomachine can be equipped with a gearbox according to the invention or with a conventional speed reducer known in the art, without needing to adapt the turbomachine's configuration. This makes it possible to design a turbomachine with a large number of identical and standardized components, in which a gearbox according to the invention or a conventional speed reducer known in the art can be integrated interchangeably, without substantial modification of the other components. This results in increased productivity during the assembly and maintenance of the turbomachine, as well as cost savings, due in particular to the reduction in the number of different parts depending on the type of turbomachine.

[0022] The meshing between the solar and the satellites of the first of said stages, and the meshing between the satellites of the last of said stages and the corona, are arranged in the same plane orthogonal to an axial direction of the speed reducer, corresponding to a direction of axis of rotation of the solar and the corona as well as of revolution of the satellites around the solar.

[0023] Each satellite comprises a first set of teeth and a second set of teeth, said teeth being coaxial and distinct from one another, each of the meshes between two satellites of directly consecutive stages being formed by the first set of teeth of a satellite belonging to a first of said stages and the second set of teeth of a satellite belonging to a second of said stages.

[0024] Providing a meshing between the solar array and the first-stage satellites, and a meshing between the last-stage satellites and the ring in the same plane orthogonal to an axial direction of the speed reducer, as well as providing two teeth per satellite, makes it possible to obtain a large reduction ratio while reducing the axial and radial size.

[0025] Other preferential, particularly convenient and advantageous characteristics of the speed reducer are described below.

[0026] According to a preferred embodiment, in each satellite, the pitch radius of the first tooth is greater than the pitch radius of the second tooth.

[0027] According to a preferred embodiment, the sum of the pitch radius of a tooth of the sun gear, the pitch radii of the first tooth of each of the satellites of a gear series and the pitch radii of the second tooth of each of the satellites of a gear series is greater than the pitch radius of a tooth of the crown gear.

[0028] According to a preferred embodiment, in the same series of gears, the center distance between the satellites of an nth and an n+1th stage directly consecutive, n ranging from 1 to A / -1, is greater than the sum of the leading radius of the first tooth of the satellite belonging to the nth stage and the leading radius of the second tooth of the satellite belonging to the n+1st stage.

[0029] According to a preferred embodiment, the center distance between the solar array and each of the satellites of the first of said stages is less than the crown head diameter.

[0030] According to a preferred embodiment, the solar is configured to be driven in rotation by a low-pressure turbomachine shaft, and in which the first tooth of each of the satellites is a driven tooth and the second tooth of each of the satellites is a driving tooth.

[0031] According to a preferred embodiment, for each of the satellites of a 2p-1, or 2p, stage, where p ranges from 1 to N / 2, one of the first, or second, gear teeth, and the second, or first, gear teeth, comprises two distinct tracks arranged on either side of the other, which includes a central track. According to a preferred embodiment, for each of the satellites of a 2p-1, or 2p, stage, where p ranges from 1 to N / 2, the first, or second, gear teeth, comprise two distinct tracks arranged on either side of the second, or first, gear teeth, which includes a central track, and the crown gear comprises two distinct tracks, each meshing with one of the tracks of the second gear teeth of the 1 / 5th stage.

[0032] According to a preferred embodiment, each satellite stage comprises three satellites, and preferably each stage comprises the same number of satellites with the satellites of the nth stage meshing one by one with the satellites of the n+1st stage, n ranging from 1 to Nl.

[0033] According to a preferred embodiment, the transmission ratio between the solar array and the corona or the satellite carrier is less than or equal to 1 / 5 or 1 / 6.

[0034] According to a preferred embodiment, the number N of satellite stages is equal to 2, and the second-stage satellite, for which n = 2, is arranged offset from a direction of alignment of the solar and the first-stage satellite, for which n = 1, and arranged circumferentially on one side of said alignment which is oriented in the direction of rotation of the solar.

[0035] The invention also relates, according to a second aspect, to a turbomachine, preferably a turbojet with an unfaired fan, comprising a turbine, a fan and a speed reducer as described above, the speed reducer being connected at the inlet to the turbine via its solar element, so as to be able to be driven into rotation by the turbine, and connected at the inlet to the fan via at least one of its ring gear and its satellite carrier, so as to be able to drive the fan into rotation.

[0036] The invention also relates, according to a third aspect, to a set of turbomachinery, comprising:

[0037] - a first turbomachine as described above, and

[0038] - a second turbomachine comprising a turbine, a fan and a speed reducer, the speed reducer being connected at the inlet to the turbine via its solar, so as to be able to be driven in rotation by the turbine, and connected at the outlet to the fan via at least one of its ring and its satellite carrier, so as to be able to drive the fan in rotation, the speed reducer comprising an odd number of satellite stages, preferably a single satellite stage; the speed reducers of the first turbomachine and the second turbomachine having the same type of connection at the outlet to the fans, among an outlet connection via at least one of the ring or the satellite carrier;so that the fan of the first turbomachine and the fan of the second turbomachine are configured to rotate in opposite directions when the speed reducers of each of the turbomachines are driven in the same direction of rotation by said turbines.

[0039] The turbomachinery in the turbomachinery set is essentially identical, differing mainly in its speed reducers. This results in the numerous design and manufacturing advantages mentioned above.

[0040] In particular, in the turbomachinery set, the two speed reducers have the same dimensions and the same input and output connection configuration, allowing for undifferentiated mounting in the same turbomachine.

[0041] The invention also relates, according to a fourth aspect, to a fixed-wing aircraft comprising a pair of wings, and at least one set of turbomachines as described above, the first turbomachine and the second turbomachine being respectively arranged on a separate wing of said pair of wings.

[0042] In particular, when the turbomachines are turbojets with unfaired fans, the rotation of the fans in opposite directions makes it possible to cancel, or largely compensate for, the effect of rotational moment exerted on the aircraft by each of the fans.

[0043] Brief description of figures

[0044] The invention will be better understood, and other details, advantages and features thereof will become apparent from the reading of the following description given by way of non-limiting example and with reference to the accompanying drawings, in which: Figure 1 is a schematic cross-sectional view of a turbomachine comprising a speed reducer according to the invention; Figure 2 is a schematic cross-sectional view detailed of the turbomachine of Figure 1 at the level of the speed reducer; Figure 3 is a schematic perspective view of the speed reducer according to a first embodiment; Figure 4 is a schematic perspective view of the speed reducer according to a second embodiment; Figure 5 is a simplified kinematic diagram of the speed reducer of Figures 4 and 5.

[0045] Detailed description of preferred embodiments

[0046] The present description is given by way of non-limiting grammar, each feature of an embodiment being able to be advantageously combined with any other feature of any other embodiment, according to any technically functional combination.

[0047] It should be noted from the outset that the figures are not necessarily to scale.

[0048] Figure 1 schematically illustrates a turbomachine 1 of the turbojet type with a blower (called turbofan in English terminology) according to a half longitudinal cross-sectional view.

[0049] The turbomachine 1 extends along a longitudinal axis X, corresponding to an axis of rotation of the rotating elements of the turbomachine 1.

[0050] As is known, the turbomachine 1 here comprises a low-pressure stage and a high-pressure stage, and thus includes a low-pressure compressor 2 and a high-pressure compressor 3 together forming the compressor, a combustion chamber 4, a high-pressure turbine 5, and a low-pressure turbine 6 together forming the turbine. The turbomachine 1 includes a low-pressure shaft 7, to which the low-pressure compressor 2 and the low-pressure turbine 6 are connected, and together form an external propulsion coil. The turbomachine 1 also includes a high-pressure shaft 8, to which the high-pressure compressor 3 and the high-pressure turbine 5 are connected, and together form an internal propulsion coil. The low-pressure shaft 7 and the high-pressure shaft 8 are collinear along their longitudinal axis X and are mounted on bearings on a housing 9 within the turbomachine 1.

[0051] The turbomachine 1 also includes a fan 10 which is configured to be driven in rotation by means of the turbine, and in particular by the low-pressure shaft 7. The turbomachine 1 here includes a fan shaft 11, on which the fan 10 is mounted. In the illustrated example, the casing 9 includes a fairing 12 which surrounds the fan 10, which is said to be shrouded, however the casing 9 may also be without a fairing 12 and the fan is then said to be unshrouded.

[0052] The turbomachine 1 also includes a speed reducer 100, through which the blower 10 is driven into rotation with a reduced speed compared to the rotation speed of the low pressure shaft 7.

[0053] The 100 speed reducer is a planetary type speed reducer. It should be noted that its input and output connections can be of any type, including planetary, epicyclic, or differential.

[0054] Figure 2 represents a detailed view of Figure 1, at the level of the speed reducer 100, on which some elements have been omitted or simplified.

[0055] The speed reducer 100 comprises a central pinion, which is called the sun gear 110, an internally toothed gear, which is called the ring gear 120, and a plurality of pinions, which are called planet gears 130 and which are arranged between the sun gear 110 and the ring gear 120. The speed reducer 100 further comprises a planet carrier 140, on which the planet gears 130 are mounted freely in rotation, for example by means of bearings, which may be of the rolling or plain bearing type, preferably mounted under the teeth of the planet gears 130.

[0056] The speed reducer 100 is connected at the input to the low pressure shaft 7 via the solar 110.

[0057] In the illustrated example, the speed reducer 100 is connected at the output to the blower shaft 11 via the ring gear 120. The planet carrier 140 is fixed in rotation here, and is connected to the housing 9. The speed reducer 100 illustrated is thus said to be of the planetary type, with the blower 10 rotating in the same direction as the turbine.

[0058] However, according to an unillustrated variant, the speed reducer 100 can also be connected at the output to the blower shaft 11 via the planet carrier 140, with the ring 120 which is fixed in rotation, and connected to the casing 9. In this variant, the speed reducer 100 is said to be of epicyclic type, with the blower 10 which rotates in the opposite direction to that of the turbine.

[0059] According to yet another variant not illustrated, the speed reducer 100 can also be connected at the output to the blower shaft 11 via one of the ring gear 120 and the planet carrier 140, with the other of the ring gear 120 and the planet carrier 140 which is free to rotate, and in particular not connected to the housing 9. In this variant, the speed reducer 100 is said to be of the differential type (or compound in English terminology), and the blower 10 rotates in the same direction as the turbine if the blower 10 is connected to the ring gear 120, and in the opposite direction to that of the turbine if the blower 10 is connected to the planet carrier 140.

[0060] The speed reducer 100 comprises a plurality of satellites 130 arranged in an even number N of satellite stages. The satellite stages are subsequently referenced En, with n an integer from 1 to N.

[0061] In the illustrated example, N is equal to two, that is to say that the speed reducer 100 comprises two satellite stages 130, namely a first stage El and a second stage E2.

[0062] Each En stage comprises at least two 130 satellites, and preferably three 130 satellites.

[0063] The stages En are arranged between the solar element 110 and the ring 120. The first stage El has each of its satellites 130 that mesh with the solar element 110. The last stage EN has each of its satellites that mesh with the ring 120. Furthermore, for the satellites of a stage En and a stage En+1 that are directly consecutive, with n ranging from 1 to A / -1, each satellite of the stage En meshes with a satellite of the stage En+1. This results in a gearing system between the solar element 110 and the ring 120, comprising a plurality of gear sets formed by the meshing of each of the satellites 130 with each other, between the solar element 110 and the ring 120. Each gear set here comprises N+l meshes.

[0064] Thus, in the illustrated example, the 130 satellites of the first stage El mesh with the solar 110, the 130 satellites of the second stage E2 mesh with the crown 120, and the 130 satellites of the first stage El each mesh with a 130 satellite of the second stage E2 directly following the first stage El.

[0065] In particular, each stage En preferentially comprises the same number M of satellites 130, each satellite of the stage En meshing one by one with exactly one distinct satellite of the stage En+1. In such a case, the speed reducer 100 comprises M series of gears each comprising N+l meshes.

[0066] In the speed reducer 100, the satellites 130 of each stage are arranged on concentric circles, and the centers of the solar element 110, the ring 120, and the centers of said concentric circles coincide. Thus, the reducer includes an axial direction, which corresponds to the same axis of rotation of the solar element 110 and the ring 120, as well as the axis of revolution of the satellites 130 around the solar element 110. The axial direction of the speed reducer here corresponds to the longitudinal axis X of the turbomachine 1.

[0067] Figure 3 illustrates the speed reducer 100 according to a first example of embodiment, and Figure 4 illustrates the speed reducer 100 according to a second example of embodiment.

[0068] The speed reducers 100 illustrated in Figures 3 and 4 share a significant number of common components, which are designated by the same reference numerals in the following description. It should be noted that the planet carrier 140 is not shown in Figures 3 and 4.

[0069] The speed reducers 100 illustrated in Figures 3 and 4 each comprise a first stage El and a second stage E2 of satellites 130 (symbolized by concentric circles of the centers of the satellites 130 of each stage, shown in dashed lines), each stage here comprising three satellites 130. Each of the satellites 130 of the first stage El, hereafter referred to as satellites 130-1, meshes with exactly one other satellite 130 of the second stage E2, the satellites 130 of the second stage E2 being hereafter referred to as 130-2. The speed reducers 100 thus each comprise three sets of three meshes between the solar element 110 and the ring gear 120.

[0070] In the illustrated embodiments, the satellites 130 each comprise a first set of teeth 131 and a second set of teeth 132, which are coaxial and distinct from each other. It should be noted that in Figures 3 and 4, the teeth of the teeth 131 and 132 are not visible, and only the tracks of the teeth 131 and 132 are shown.

[0071] Each of the meshes between two satellites of directly consecutive stages is formed by the first tooth 131 of a satellite belonging to a first of the stages and the second tooth 132 of a satellite belonging to a second of the stages.

[0072] In the illustrated examples, the first tooth 131 of each of the satellites 130-2 of the second stage E2 meshes with the second tooth 132 of the satellites 130-1 of the first stage El.

[0073] The first tooth 131 of the satellites 130-1 of the first stage El meshes with the tooth of the solar 110, and the second tooth 132 of the satellites 130-2 of the second stage E2 meshes with the tooth of the ring 120.

[0074] Thus, the first gear 131 of the satellites 130 is a driven gear and the second gear 132 of the satellites 130 is a driving gear. In particular, the meshing between the solar element 110 and the satellites 130-1 of the first stage E1, and the meshing between the satellites 130-2 of the second and final stage E2 and the ring gear, are arranged in the same plane PI orthogonal to the axial direction of the speed reducer, and thus to the longitudinal axis X of the turbomachine 1.

[0075] The speed reducer 100 can be substantially symmetrical with respect to a plane of symmetry Ps substantially orthogonal to the axial direction of the speed reducer. In particular, the gears of the speed reducer 100 can be doubled, on either side of the plane of symmetry Ps.

[0076] In particular, for each of the satellites 130 of a 2p-l, or 2p, stage, where p ranges from 1 to N / 2, one of the first gear teeth 131, or second gear teeth 132, and the second gear teeth 132, or first gear teeth 131, respectively, comprises two distinct tracks arranged on either side of each other, one of the first gear teeth 131, or second gear teeth 132, and the second gear teeth 132, or first gear teeth 131, respectively, which comprises a so-called single or central track. The central track may be formed by two juxtaposed distinct tracks, particularly when the central track has a herringbone pattern, with each of the distinct tracks then forming a half-herringbone pattern.

[0077] In the first embodiment, illustrated in Figure 3, the speed reducer 100 has a so-called "spread-out" configuration, in which the meshing between the solar element 110 and the satellites 130-1 of the first stage El, and the meshing between the satellites 130-2 of the second and final stage E2 and the ring gear 120, are duplicated on either side of the symmetry plane Ps and arranged in the same planes Pl-1 and Pl-2 orthogonal to the axial direction of the speed reducer, located on either side of the symmetry plane Ps. The meshing between the satellites 130-1 of the first stage El and the satellites 130-2 of the second stage E2 is located in the same plane orthogonal to the axial direction, corresponding here to the symmetry plane Ps.

[0078] The first tooth 131 of each of the satellites 130-1 of the first stage El has a first track 131-1 and a second track 131-2 located on either side of the central track of the second tooth 132. In particular, tracks 131-1 and 131-2 are respectively located in the planes Pl-1 and Pl-2.

[0079] The second tooth 132 of each of the satellites 130-2 of the second stage E2 has a first track 132-1 and a second track 132-2 located on either side of the central track of the first tooth 131. In particular, tracks 132-1 and 132-2 are respectively located in the Pl-1 and Pl-2 planes.

[0080] In this embodiment, the ring 120 comprises a first track 120-1 and a second track 120-2, each meshing respectively with tracks 132-1 and 132-2 of the second gear set of each of the satellites 130-2 of the second stage E2. In particular, the ring 120 may comprise two distinct half-rings, each comprising one of the tracks 120-1 and 120-2. The two half-rings are here arranged here, each in one of the planes Pl-1 and Pl-2, on either side of the plane of symmetry Ps.

[0081] In the second embodiment, illustrated in Figure 4, the speed reducer 100 has a so-called "grouped" configuration, in which the meshing between the solar element 110 and the satellites 130-1 of the first stage El, and the meshing between the satellites 130-2 of the second and final stage E2 and the ring, are located in the same plane PI, corresponding to the plane of symmetry Ps. The meshing between the satellites 130-1 of the first stage El and the satellites 130-2 of the second stage E2 is here duplicated and located in the same planes Pl-1 and Pl-2 orthogonal to the axial direction of the speed reducer, situated on either side of the plane of symmetry Ps.

[0082] The second tooth 132 of each of the satellites 130-1 of the first stage El has a first track 132-1 and a second track 132-2 located on either side of the central track of the first tooth 131. In particular, tracks 132-1 and 132-2 are respectively located in the Pl-1 and Pl-2 planes.

[0083] The first tooth 131 of each of the satellites 130-2 of the second stage E2 has a first track 131-1 and a second track 131-2 located on either side of the central track of the second tooth 132. In particular, tracks 131-1 and 131-2 are respectively located in the Pl-1 and Pl-2 planes.

[0084] In this embodiment, the 120 ring is in one piece, and is arranged in the plane of symmetry Ps.

[0085] Regardless of the embodiment, gears comprising a central race, located in the plane of symmetry Ps, are preferably of the straight, helical, or herringbone type. Gears comprising two distinct raceways, located in planes Pl-1 and Pl-2, are preferably of the straight or herringbone type.

[0086] In a planetary configuration, in which the solar 110 and the corona 120 are co-rotating, the speed reducer 100 is preferably configured so that the absolute transmission ratio between the solar 110 and the corona 120 is less than or equal to approximately 1 / 5. In other words, the reduction ratio between the solar 110 and the corona 120 is greater than or equal to 5.

[0087] In an epicycloidal configuration, in which the solar 110 and the satellite carrier 140 are counter-rotating, the speed reducer 100 is preferentially configured so that the absolute transmission ratio between the solar 110 and the satellite carrier 140 is less than or equal to approximately 1 / 6. In other words, the reduction ratio between the solar 110 and the ring 120 is greater than or equal to 6.

[0088] As mentioned above, the satellites 130 can be mounted on the satellite carrier 140 via bearings, for example, roller or plain bearings. The bearings can be mounted in the satellites 130, under the gear teeth 131 and 132.

[0089] Figure 5 is a kinematic and geometric diagram of the speed reducer 100, on which only a series of gears, including the solar, a satellite 130-1 of the first stage El, a satellite 130-2 of the second stage E2, and the ring 120, has been shown.

[0090] The speed reducer 100 can be configured to cancel, or minimize, the moments of force exerted on the bearings of the satellites 130.

[0091] As is known, the gear elements of the speed reducer 100, which are in particular circular toothed elements, can be defined in particular by the dimensions of their leading circle, passing through the top of the teeth, and their pitch circle, passing through the points of the same tangential velocity of a meshing.

[0092] In the illustrated speed reducer 100, for each of the planet gears 130, the pitch radius of the first gear 131, which is driven, is greater than the pitch radius of the second gear 132, which is driving. This results in a reduction of the output speed relative to the input speed of the speed reducer 100.

[0093] Moreover, here, the center-to-center distance between the solar 110 and each of the satellites 130 of the first stage El is less than the crown head diameter 120.

[0094] In the illustrated example, in particular, the sum of the pitch radius of the teeth of the sun gear 110 and the pitch radii of the first teeth 131 of each of the satellites 130 in a gear set is greater than the pitch radius of the teeth of the ring gear 120. As can be seen in Figure 5, the satellite 130-2 of the second stage E2 extends beyond the pitch diameter of the ring gear 120. Structurally, as can be seen in Figures 3 and 4, this also means that the satellites 130-2 of the second stage E2, and final stage, can extend radially between or on either side of the ring gear 120. This results in a high radial compactness of the speed reducer 100.

[0095] Furthermore, the center distance between the satellites 130 of two stages En and En+1 directly consecutive of the same series of gears, n going from 1 to Nl, is greater than the sum of the leading radius of the first tooth 131 of the satellite belonging to stage En and the leading radius of the second tooth 132 of the satellite belonging to stage En+1. This avoids any collision of teeth of satellites of consecutive stages, which are not intended to cooperate.

[0096] In the illustrated example, the center distance between the satellites 130-1 of the first stage El and the satellites 130-2 of the second stage E2 is greater than the sum of the head radius of the first tooth 131 of the satellite 130-1 and the head radius of the second tooth 132 of the satellite 130-2.

[0097] Figure 5 also illustrates a particularly advantageous arrangement of the satellites in the plane orthogonal to the axial direction of the speed reducer 100. Such an arrangement makes it possible to at least partially cancel the meshing forces on each of the satellites, and to reduce or even cancel the resultant force on the bearings of the satellites 130.

[0098] In the illustrated example, the lines connecting respectively the center of solar 110 to the center of satellite 130-1 of the first stage El, and the center of solar 110 to the center of satellite 130-2 of the second stage E2, form an angle, in other words, solar 110 and satellites 130-1 and 130-2 are not aligned but form a triangle.

[0099] In particular, the angle formed between the line connecting the center of solar 110 to the center of satellite 130-1 of the first stage E1, and the line connecting the center of solar 110 to the center of satellite 130-2 of the second stage E2, is oriented in the direction of rotation of solar 110. Thus, satellite 130-2 of the second stage E2 is circumferentially offset with respect to the first satellite 130-1 in the direction of rotation of solar 110.

[0100] An equivalent "optimal" arrangement can be determined by calculating the resultant forces on the landings for any other even number n of floors.

[0101] It is generally recalled that the speed reducer 100 can include any even number n of stages, and any number of satellites per stage, the embodiments described above being adapted accordingly.

[0102] Furthermore, the invention relates to a set of turbomachines, one of which corresponds to a turbomachine 1 as described above, comprising a speed reducer 100 including for example two stages, here connected to the blower 10 in a planetary configuration, i.e. by its ring 120.

[0103] The turbomachinery set further includes a second turbomachine, the second turbomachine being in particular able to be identical in every respect to the first turbomachine 1, except with regard to the speed reducer.

[0104] In the second turbomachine, the speed reducer is of the same type as in the first turbomachine 1, and is here connected to the fan 10 in a planetary configuration, i.e. by its ring 120. However, the speed reducer of the second turbomachine has an odd number of satellite stages, and in particular only one satellite stage, such as a conventional speed reducer known in the art.

[0105] As a result, the blowers of each of the turbomachines in the turbomachinery set rotate in opposite directions, while their turbines rotate in the same direction.

[0106] Since the gearboxes of each turbomachine have the same type of connection—here planetary, but also epicyclic or differential—it is possible to integrate either gearbox in the same way into otherwise identical turbomachines. Furthermore, as described above, the gearbox 100 according to the invention can be designed in a particularly compact manner, especially with two planetary gear stages, and have the same overall dimensions as the gearbox of the other turbomachine, which is, in particular, a conventional single-stage planetary gearbox. This results in easier integration into the turbomachine.

[0107] Such a set of turbomachinery can be advantageously used in an aircraft, in particular a fixed-wing aircraft comprising a pair of wings, such as an airplane (not shown), especially of the airliner type.

[0108] Each of the aircraft's wings, which are positioned opposite each other with respect to the fuselage, houses one of the turbomachinery from the turbomachinery set. Thus, the fans located on either side of the aircraft fuselage rotate in opposite directions. This reduces or even eliminates the torques exerted on the aircraft by the reaction forces to the rotation of the fans.

[0109] Preferably, the turbomachinery in the turbomachinery set has unducted fans, meaning the turbomachinery is of the propfan or open-fan type (according to English terminology). Specifically, the aircraft is twin-engine, but could also be four-engine and have two sets of turbomachinery, with one pair of turbomachinery per wing having fans rotating in the same direction, and the other pair having fans rotating in the opposite direction. It should be noted more generally that the invention is not limited to the examples described and illustrated.

[0110] According to other, unillustrated, variant implementations:

[0111] - Satellite stages include different numbers of satellites.

[0112] - The meshing between the solar system, the satellites and the corona can be ensured by contact, by friction, or by magnetic field, rather than by gearing.

[0113] - The teeth of the solar, and / or satellites and / or crown can be of the straight tooth type, helical tooth type, or chevron tooth type.

Claims

Demands 1. Speed ​​reducer (100) for driving a turbomachine blower, the speed reducer comprising a solar element (110), a ring (120), a plurality of satellites (130), and a satellite carrier (140) supporting said satellites, the solar element (110) being configured to be mechanically connected to a turbomachine turbine to be driven into rotation by it, and at least one of the ring or the satellite carrier being configured to be mechanically connected to a turbomachine blower to drive into rotation the latter, the satellites (130) are arranged according to / V stages of satellites disposed between the solar element and the ring, / V being even and preferably equal to 2, each nth stage, n from 1 to N, comprising at least two satellites;a first of said stages, for which n=l, each having its satellites meshing with the solar and a last of said stages, for which n=N, each having its satellites meshing with the corona (120); and in that, for the satellites of an nth and an n+1th stage directly consecutive, n going from 1 to A / -1, each satellite of the nth stage meshes with a satellite of the n+1st stage, the speed reducer being characterized in that the meshing between the solar (110) and the satellites of the first of said stages, and the meshing between the satellites of the last of said stages and the corona (120), are arranged in the same plane orthogonal to an axial direction of the speed reducer (100), corresponding to a direction of the axis of rotation of the solar and the corona as well as of revolution of the satellites around the solar;and in that the satellites (130) each comprise a first set of teeth (131) and a second set of teeth (132), said teeth being coaxial and distinct from each other, each of the meshes between two satellites of directly consecutive stages being formed by the first set of teeth of a satellite belonging to a first of said stages and the second set of teeth of a satellite belonging to a second of said stages.; 2. Speed ​​reducer (100) according to claim 1, wherein in each satellite (130), the pitch radius of the first tooth (131) is greater than the pitch radius of the second tooth (132).

3. Speed ​​reducer (100) according to any one of claims 1 or 2, wherein the sum of the pitch radius of a tooth of the sun gear (110), the pitch radii of the first tooth (131) of each of the satellites of a gear series and the pitch radii of the second tooth (132) of each of the satellites of a gear series is greater than the pitch radius of a tooth of the ring gear (120).

4. Speed ​​reducer (100) according to claim 3, wherein, in the same series of gears, the center distance between the satellites of an nth and an n+1st stage directly consecutive, n ranging from 1 to A / -1, is greater than the sum of the leading radius of the first tooth of the satellite belonging to the nth stage and the leading radius of the second tooth of the satellite belonging to the n+1st stage.

5. Speed ​​reducer (100) according to any one of claims 3 or 4, wherein the center distance between the solar (110) and each of the satellites of the first of said stages is less than the head diameter of the ring (120).

6. Speed ​​reducer (100) according to any one of claims 3 to 5, wherein the solar (110) is configured to be driven in rotation by a low pressure turbomachine shaft, and wherein the first toothing (131) of each of the satellites is a driven toothing and the second toothing (132) of each of the satellites is a driving toothing.

7. Speed ​​reducer (100) according to any one of claims 3 to 6, in which, for each of the satellites of a 2p-l stage, respectively 2p, p ranging from 1 to N / 2, one of the first gear (131), respectively second gear (132), and the second gear (132), respectively first gear (131), comprises two separate tracks arranged on either side of the other of the first gear (131), respectively second gear (132), and the second gear (132), respectively first gear (131), which comprises a central track.

8. Speed ​​reducer (100) according to claim 7, in which, for each of the satellites of a 2p-1, respectively 2p, p ranging from 1 to N / 2 stage, the first toothing (131), respectively second toothing (132), comprises two separate tracks arranged on either side of the second toothing (132), respectively first toothing (131), which comprises a central track, and the ring gear (120) comprises two separate tracks each meshing with respectively one of the tracks of the second toothing (132) of the / V-th stage.

9. Speed ​​reducer (100) according to any one of claims 1 to 8, wherein each satellite stage (130) comprises three satellites, and preferably each stage comprises the same number of satellites with the satellites of the nth stage meshing one by one with the satellites of the n+1st stage, n ranging from 1 to N1.

10. Speed ​​reducer (100) according to any one of claims 1 to 9, wherein the transmission ratio between the solar (110) and the ring (120) or the satellite carrier (140) is less than or equal to 1 / 5 or 1 / 6.

11. Turbomachine (1), preferably a turbojet with an unfaired fan, comprising a turbine, a fan (10) and a speed reducer (100) according to any one of claims 1 to 10, the speed reducer being connected at the inlet to the turbine via its solar (110), so as to be able to be driven in rotation by the turbine, and connected at the outlet to the fan (10) via at least one of its ring and its satellite carrier, so as to be able to drive the fan in rotation.

12. Turbomachinery set, comprising: - a first turbomachine (1) conforming to claim 11, and - a second turbomachine comprising a turbine, a fan and a speed reducer, the speed reducer being connected at the inlet to the turbine via its solar, so as to be able to be driven in rotation by the turbine, and connected at the inlet to the fan via at least one of its ring and its satellite carrier, so as to be able to drive the fan in rotation, the speed reducer comprising an odd number of satellite stages, preferably a single satellite stage; the speed reducers of the first turbomachine and the second turbomachine having the same type of connection at the outlet to the fans, among an outlet connection via at least one of the ring or the satellite carrier;so that the fan of the first turbomachine and the fan of the second turbomachine are configured to rotate in opposite directions when the speed reducers of each of the turbomachines are driven in the same direction of rotation by said turbines.

13. Fixed-wing aircraft comprising a pair of wings, and at least one set of turbomachines according to claim 12, the first turbomachine (1) and the second turbomachine being respectively arranged on a separate wing of said pair of wings.

Images