BLOWER MODULE EQUIPPED WITH AN OIL TRANSFER DEVICE
Patent Information
- Application Number
- FR2021002622
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-03-16
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2041-03-16
Smart Images
Figure 00000016_0000 
Figure 00000016_0001 
Figure 00000017_0000
Abstract
Description
Title of the invention: BLOWER MODULE EQUIPPED WITH AN OIL TRANSFER DEVICE Technical field of the invention
[0001] The present invention relates to a fan module for an aircraft turbomachine, this module comprising an oil transfer device. Technical background
[0002] An aircraft turbomachine conventionally comprises a gas generator comprising, from upstream to downstream in the direction of flow of the gases in operation, at least one compressor, an annular combustion chamber and at least one turbine.
[0003] The gases entering the gas generator are compressed in the compressor(s) and then mixed with fuel and burned in the combustion chamber. The combustion gases flow and expand in the turbine(s) to drive its rotor(s).
[0004] In the case of a twin-body turbomachine, respectively low pressure and high pressure, the rotor of the high pressure turbine is connected by a high pressure shaft to the rotor of the high pressure compressor, and the rotor of the low pressure turbine is connected by a low pressure shaft to the rotor of the low pressure compressor.
[0005] The turbomachine may be equipped with one or more propellers, shrouded or unshrouded. In the case of a shrouded propeller located upstream of the gas generator, this propeller is called a fan and is driven by the low pressure shaft of the gas generator.
[0006] The blower generates a gas flow in operation which divides into a first flow, called the primary flow which flows into the gas generator as discussed above, and a second flow, called the secondary flow, which flows around the gas generator.
[0007] The bypass ratio, which is the ratio between the flow rate of the secondary flow and the flow rate of the primary flow, is increasingly important in modern turbomachines, which results in an increase in the diameter of the fan and a reduction in the diameter of the gas generator.
[0008] To limit the rotation speed of the fan, in particular of turbomachines with a high bypass ratio, it is known to drive this fan via a reducer, generally of the epicyclic or planetary gear type. The low pressure shaft thus drives the fan via the reducer.
[0009] A fan, or a propeller in general, may comprise pitched blades variable, that is to say that each of the blades has an orientation around a radial axis which can be precisely adjusted. The blades are carried by a hub in the form of a polygonal ring and are moved in rotation around these axes by means of a common hydraulic actuator which is mounted inside the hub. This actuator is supplied with oil and can be located in a rotating reference when it is integral in rotation with the hub and the fan.
[0010] The turbomachine comprises a lubrication system comprising an oil reservoir and a pump, which is generally located in a fixed reference frame. It is therefore understood that the oil supply to the actuator from the lubrication system must be done by an oil transfer device from a fixed reference frame to a rotating reference frame. A device of this type is commonly called an OTB, an acronym for the English expression OU Transfer Bearing.
[0011] This type of device can be mounted in a fan turbomachine of the aforementioned type to supply the actuator with oil but also to supply the reducer with lubricating oil. This type of device can also be mounted in another type of turbomachine, such as for example a turbomachine equipped with an unducted propeller with variable-pitch blades, of the turboprop type.
[0012] In the current art, an oil transfer device comprises a stator ring which has an internal cylindrical surface and internal oil pipes which each open onto this internal cylindrical surface. These pipes are connected by conduits to the aforementioned lubrication system.
[0013] The device further comprises a shaft engaged in the ring and rotatable about an axis inside this ring. The shaft has an external cylindrical surface extending inside the internal cylindrical surface of the ring, and internal oil pipes which each open onto this external cylindrical surface. These pipes are connected by conduits to the actuator for its oil supply.
[0014] In the current technique, the external cylindrical surface of the shaft comprises annular grooves for housing annular sealing segments. These segments are capable of moving in the grooves and are configured to bear radially on the internal surface of the ring to limit and control oil leaks. The outlets of the aforementioned pipes are located between two adjacent segments which therefore ensure that a maximum of oil supplied by each pipe of the ring feeds a corresponding pipe of the shaft. The number of segments is equal to twice the number of pipes. Document GB-A-824,332 describes an oil transfer device of this type.
[0015] However, this technology is not satisfactory for several reasons. Deformations in operation (linked to differential thermal expansions and efforts) and the manufacturing and assembly tolerances of the parts make it difficult to precisely control these leaks. The device includes many parts, which complicates assembly. The manufacture and assembly of such a device is therefore relatively long and expensive. Furthermore, the greater the number of pipes in the device, the greater the number of sealing segments, and the greater the axial dimension and therefore the axial size of the device to be able to mount these different segments. An oil transfer device can be complex to integrate into a turbomachine due to its size. Finally, the service life of such a device is generally limited due to potential misalignments between the shaft and the ring during operation and the wear of the sealing segments, which can be accentuated by these misalignments as well as by the rotation speed of the shaft.The larger the diameter of the device, the greater the peripheral speed of the shaft and the wear of the segments.
[0016] It would be advantageous to provide a plain bearing between the surfaces of the ring and the shaft. One solution would then be to mount a first hoop on the inner surface of the ring and a second hoop on the outer surface of the shaft, so that these hoops define the plain bearing between them. These hoops would then include oil passage orifices in fluid communication with the pipes of the ring and the shaft, in order to supply oil to the plain bearing. To maintain the clearance between the hoops and avoid misalignments between them, it could be useful to also provide rolling bearings on either side of the plain bearing, the inner and outer rings of which would be mounted on the shaft and the ring respectively.
[0017] However, this solution would not be satisfactory because the number of parts of the transfer device would be significant (bearings with rollers and rings, frets, etc.) and the assembly of the device would be complex and expensive to carry out.
[0018] The invention thus provides an improved oil transfer device which solves all or part of the problems of the prior art. Summary of the invention
[0019] The invention relates to a fan module for an aircraft turbomachine, this module comprising a fan which comprises a fan shaft and variable-pitch fan blades, and an oil transfer device configured to ensure oil transfer between a stator and an actuator which is rotationally integral with the fan shaft and which is configured to control the pitch of the fan blades, this device comprising:
[0020] - a stator ring comprising a first cylindrical surface, for example internal, and internal oil pipes which each open onto said first cylindrical surface, and
[0021] - a shaft engaged in or on said ring and comprising a second surface cy lindrique extending inside or around said first cylindrical surface, the shaft comprising internal oil channels which each open onto said second cylindrical surface,
[0022] characterized in that it further comprises:
[0023] - a plain bearing located between said first and second cylindrical surfaces, and
[0024] - rolling bearings mounted between the ring and the shaft, on either side of the bearing smooth, each of these rolling bearings comprising rolling elements between two annular rolling tracks,
[0025] in that one of the elements chosen from the ring and the shaft carries rings defining first tracks of the rolling bearings, the second tracks of these rolling bearings being integrated into the other of these elements,
[0026] and in that the plain bearing is produced by a single hoop inserted between the first and second cylindrical surfaces, and fixed on one of said elements.
[0027] The invention thus proposes an oil transfer device without sealing members or segments between the facing cylindrical surfaces of the stator ring and the shaft. Instead, a plain bearing is provided between these surfaces. Rolling bearings are mounted on either side of this plain bearing so as to guarantee the radial thickness of the plain bearing, whatever the speed of the turbomachine and the peripheral speed of the shaft of the transfer device. The rolling bearings are automatically lubricated by the oil which leaks from the plain bearing during operation. The rolling bearings also ensure the limitation of oil leaks outside the plain bearing and the device. The rolling bearings also make it possible to eliminate the risks of misalignment between the ring and the shaft and therefore the risks of contact between them and of wear.The sealing segments therefore no longer constitute wearing parts of the device, which therefore has an optimized lifespan compared to the prior art.
[0028] Furthermore, the number of parts of the device is reduced by the use of a single hoop instead of two and by the use of rolling bearings with rings integrated into the ring or the shaft. This makes it possible to limit the stacking of assembly and machining tolerances. The invention makes it possible to facilitate the production and assembly of the device.
[0029] The module according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another:
[0030] — the rolling bearings are roller bearings,
[0031] - one of the elements carries the rings of the rolling bearings as well as the hoop;
[0032] - the fret has two cylindrical surfaces extending around each other, one of which cylindrical hooping surface and a cylindrical centering surface, this cylindrical centering surface having a diameter equal to the diameters of the second rolling tracks;
[0033] - the stator ring carries the rings and the hoop;
[0034] - the rings of the rolling bearings have identical internal diameters;
[0035] - one of the elements carries the rings and the other of the elements carries the hoop;
[0036] - the ring carries the hoop and the shaft carries the rings;
[0037] - the fret has two cylindrical surfaces extending around each other, one of which cylindrical hooping surface on the ring and a cylindrical centering surface on the shaft, the rings of the rolling bearings having internal diameters different from each other and different from the diameter of the internal cylindrical surface of the hoop;
[0038] - the hoop comprises orifices which are on the one hand located opposite the outlets pipes of one of the elements, and which are in fluid communication with the pipes of the other of the elements by means of annular grooves formed at the outlets of the pipes of this other element;
[0039] - the blower is driven in rotation by a reducer, said device being mounted upstream of the reducer and being configured to supply oil to the reducer as well as the actuator or even the reducer,
[0040] - the blower is driven by a shaft which is guided by rolling bearings which is coupled to the shaft of the device,
[0041] — the reducer is of the planetary type, that is to say with a stationary planet carrier in rotation and therefore with rotating mobile crown,
[0042] — the reducer is of the epicyclic type, that is to say with a crown which is immobile in rotation and therefore with a rotating mobile satellite carrier,
[0043] — the device supplies the reducer with lubricating oil, and in particular to the less part of its bearings and teeth,
[0044] — the device is configured to supply the actuator with an oil pressure between 2 and 200 bars, and preferably between 5 and 130 bars,
[0045] — the device is configured to supply the reducer with an oil pressure between 2 and 50 bars, and preferably between 5 and 20 bars.
[0046] The invention also relates to an aircraft turbomachine, comprising a module as described above. Brief description of the figures
[0047] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:
[0048] [fig. 1] [fig.l] is a half schematic view in axial section of a turbomachine equipped with an oil transfer device,
[0049] [fig.2] [fig.2] is a larger scale view of part of [fig.l],
[0050] [fig.3] [fig.3] is a half schematic view in axial section of a device for oil transfer according to the prior art,
[0051] [fig.4] [fig.4] is a half schematic view in axial section of a device of oil transfer according to a first embodiment of the invention, and
[0052] [fig.5] [fig.5] is a half schematic view in axial section of a device for oil transfer according to a second embodiment of the invention. Detailed description of the invention
[0053] [fig.l] shows a turbomachine 10 which comprises, in a conventional manner, a fan 12, a low pressure (LP) compressor 14, a high pressure (HP) compressor 16, an annular combustion chamber 18, a high pressure (HP) turbine 20, a low pressure (LP) turbine 22 and an exhaust nozzle 24.
[0054] The rotors of the high-pressure compressor 16 and of the high-pressure turbine 20 are connected to each other by a high-pressure shaft 26 and form with it a high-pressure (HP) body which is guided in rotation about the longitudinal axis A of the turbomachine by rolling bearings 28, 30. A first bearing 28 is mounted between an upstream end of the shaft 26 and of the HP body and an inter-compressor casing 32 located between the LP 14 and HP 16 compressors. A second bearing 30 is mounted between a downstream end of the shaft 26 and of the HP body and an inter-turbine casing 34 located between the LP 22 and HP 24 turbines.
[0055] The rotors of the LP compressor 14 and the LP turbine 22 are connected to each other by a low-pressure shaft 36 and form with it a low-pressure (LP) body which is guided in rotation about the longitudinal axis A of the turbomachine by rolling bearings 38, 40. At least one bearing 38 is mounted between an upstream end of the shaft 36 and the LP body and an inlet casing 42 located upstream of the LP compressor 14. Other bearings 40 are mounted between a downstream end of the shaft 36 and the LP body and an exhaust casing 44 located downstream of the LP turbine 22.
[0056] The fan 12 is driven by a fan shaft 46 which is driven by the LP shaft 36 by means of a reducer 48. This reducer 48 is generally of the planetary or epicyclic type.
[0057] The following description concerns a planetary type reducer, the planet carrier and the sun gear of which are rotatable, the crown of the reducer being fixed in the motor reference frame.
[0058] The reducer 48 is positioned in the upstream part of the turbomachine. A fixed structure comprising schematically, here, an upstream part 50a and a downstream part 50b which composes the motor casing or stator 50 is arranged so as to form an enclosure E surrounding the reducer 48. This enclosure E is here closed upstream by a seal 52 at the level of a bearing 54 allowing the fan shaft 46 to pass through, and downstream by a seal 55 at the level of the bearing 38 allowing the LP shaft 36 to pass through.
[0059] The enclosure E is arranged inside the inlet casing 42 which is located between an inlet rectifier vane 56 and the LP compressor 14.
[0060] [Fig.2] shows the reducer 48 on a larger scale.
[0061] The reducer 48 comprises a sun gear 48a centered on the axis A and coupled to the BP shaft 36 for example by means of splines.
[0062] The reducer 48 comprises a ring gear 48b which is rotatable about the axis A and is connected to the fan shaft 46 for its rotational drive. The ring gear 48b is guided by two bearings 54, 58 carried by the input casing 42, these bearings 54, 58 being located upstream of the reducer 48.
[0063] The reducer 48 finally comprises satellites 48c which are arranged around the axis A and meshed with the sun gear 48a and the crown 48b. These satellites 48c are carried by a planet carrier 48d which is fixed to the input casing 42.
[0064] The fan 12 of [fig.l] comprises variable-pitch blades 12a and is associated with an actuator 62 which makes it possible to centrally control the positioning of the blades 12a around their axes B, which are generally radial axes relative to the axis A of the turbomachine.
[0065] Each of the blades 12a comprises a foot 12b forming a pivot which is housed in a housing of a hub 64 in the form of a polygonal ring, and which is connected by a connection system 66 to a piston of the actuator 62.
[0066] The actuator 62 extends along the axis A and its piston is movable in translation. along this axis, for example from a first position in which the blades 12a are feathered to a second position in which the blades 12a obstruct the passage of air through the fan 12.
[0067] The air flow F1 which passes through the fan 12 is divided into two annular and coaxial flows downstream of the fan, by an annular separator 68 which extends around the blading 56. A first air flow called primary flow F2 flows in a primary vein and passes through this blading 56 and flows into the compressors 14 and 16 to be compressed. This compressed air is then mixed with fuel and then burned in the combustion chamber 18. The combustion gases are then expanded in the turbines 20, 22 to drive their rotors and the LP 36 and HP 26 shafts, then flow into the nozzle 24.
[0068] A second air flow called secondary flow F3 flows in a secondary vein which is internally defined by an annular engine casing 70 which extends longitudinally around the compressors 14, 16, the combustion chamber 18 and the turbines 20, 22, and externally by an annular nacelle casing 72 which extends longitudinally around the fan 12 and a portion of the engine. This nacelle casing 72 is connected to the engine by outlet guide vanes 42a of the inlet casing 42. These guide vanes 42a are structural and are configured to straighten the airflow exiting the fan 12.
[0069] The actuator 62 is hydraulic and operates with a fluid, oil, which comes from a lubrication system generally located in the nacelle or between the compressors 14, 16 and the casing 70 (i.e. in the engine) and therefore in a fixed reference frame of the turbomachine. On the contrary, the actuator 62 is located in a rotating reference frame.
[0070] As can be seen in [fig.2], the turbomachine 10 comprises a device 74 for transferring oil from the fixed reference mark of the engine to the rotating reference mark in which the actuator 62 is located.
[0071] In the example shown, the device 74 is located upstream of the reducer 48 and comprises one or more oil supply channels 76 to supply the actuator 62 or also to possibly lubricate the reducer 48.
[0072] The dotted line in [fig.2] symbolizes one of these paths along its entire route, from the fixed reference point to the actuator 62: crossing the primary vein to the device 74, crossing the reducer 48 (between its satellites or through the axes of these satellites), and routing along the planet carrier s then the fan shaft 46.
[0073] [Fig. 3] illustrates an oil transfer device 74 which comprises:
[0074] - a stator ring 80 comprising an internal cylindrical surface 80a and channels internal oil outlets 80b which each open onto said internal cylindrical surface 80a,
[0075] - a shaft 82 engaged in the stator ring 80 and movable in rotation around the axis Inside this ring 80, the shaft 82 comprising an external cylindrical surface 82a extending inside the surface 80a, and internal oil pipes 82b which each open onto the surface 82a.
[0076] A plain bearing P is arranged between the surfaces 80a, 82a. For this, a first hoop 84a is mounted in the ring 80 and covers its internal surface 80a, and a second hoop 84b is mounted on the shaft 82 and covers its external surface 82a.
[0077] The frets allow precise machining of the surfaces of the plain bearing, this machining being more difficult when it is carried out directly on a part, in particular inside the ring. These frets 84a, 84b define between them the plain bearing P and comprise orifices 86 for the passage of oil in fluid communication with the pipes 80b, 82b of the ring 80 and of the shaft 82, in order to supply the plain bearing P with oil.
[0078] Rolling bearings 88, 90 are mounted between the ring 80 and the shaft 82, on either side of the plain bearing P. Each of these bearings 88, 90 comprises an inner ring 88a, 90a which is mounted on the hoop 84b and an outer ring 88b, 90b which is mounted in ring 80.
[0079] This technology has many of the problems described above.
[0080] The present invention makes it possible to remedy all or part of these problems thanks to an oil transfer device, a first embodiment of which is illustrated in [fig.4],
[0081] The reference numbers used in the above to designate certain elements are repeated in the description which follows and in Figures 6 and 7 to the extent that they designate these same elements.
[0082] The oil transfer device 174 of [fig.4] also comprises a stator ring 180 and a shaft 182 engaged in the stator ring 180 and rotatable about the axis A inside this ring 180.
[0083] The ring 180 comprises an internal cylindrical surface 180a and internal oil pipes 180b which each open onto the surface 180a. The pipes 180b all have a radial orientation and are arranged one behind the other along the axis A. There are three of them in the example shown.
[0084] Although the pipes 180b are here shown in the same axial plane, they could be located respectively in different axial planes. This depends in particular on the pipes 192 to which they are connected and on the arms 42b through which these pipes pass. In yet another variant, the pipes 180b could comprise radially external ends located in the same axial plane and ends distributed angularly around the axis A and opening onto the surface 180a.
[0085] Each of the pipes 180b comprises a radially internal end which forms the aforementioned outlet and a radially external end which forms a port 190 for connection to an oil pipe 192. The port 190 forms a female part and one end of the pipe 192 forms a male part engaged in a sealed manner in the port 190. These pipes 192 are intended to pass through the stator of the reducer 48, tubular arms 42b of the inlet casing 42 which are located in the flow path of the primary flow F2 then guide vanes 42a which are located in the flow path of the secondary flow F3, to reach the lubrication system located in the nacelle (see [fig.l]). An alternative is to mount the lubrication system in the engine (between the primary stream - compressors 14 and 16) and the casing 70 of the secondary stream, so that these pipes 192 do not cross the secondary flow F3.
[0086] The ring 180 has a generally cylindrical shape and comprises an upstream cylindrical rim 200a and a downstream cylindrical rim 200b. These rims 200a, 200b have identical or similar diameters.
[0087] As shown schematically in [fig.2], the ring 180 can be connected by a flexible connection to the planet carrier 48d. In the example shown, this flexible connection comprises a bellows-shaped wall 202.
[0088] A hoop 204 is fixed inside the ring 180 so as to cover its surface 180a. This hoop 204 extends over a major part of the length of the ring 180 and comprises a radially external annular rim 204a at its upstream end which is in axial support on a cylindrical bearing surface of the ring 180. As its name indicates, the hoop 204 is mounted by hooping in the ring 180. The hooping associated with the support of its rim 204a ensures the immobilization of the hoop 204 with respect to the ring 180.
[0089] The hoop 204 comprises an annular row of radial orifices 206 in line with each of the pipes 180b. Furthermore, an annular groove 208 is formed at the internal periphery of the ring 180 and in line with each of the pipes 180b, this groove 208 being closed on the inside by the hoop 204. It is therefore understood that each pipe 180b supplies a groove 208 and that each groove 208 distributes oil to the orifices 206 of the hoop 204.
[0090] The hoop 204 comprises an external cylindrical hooping surface which is in contact with the internal surface 180a of the ring 180, and an internal cylindrical centering surface intended to be separated by a predetermined radial distance from the external surface 182a of the shaft 182 to define the plain bearing P.
[0091] The shaft 182 does not carry a hoop. This removal makes it possible to reduce the number of tolerance stacking interfaces by three. Consequently, the resulting tolerance on the clearances is greatly reduced by reducing the number of contributors and therefore the resulting clearances are reduced, in particular between the rotor and the stator.
[0092] The shaft 182 comprises an external cylindrical surface 182a extending inside the surface 180a and internal oil pipes 182b which each open onto the surface 182a. The pipes 182b all have a radial orientation and are arranged one behind the other along the axis A. There are three of them in the example shown.
[0093] An annular groove 210 is formed at the external periphery of the shaft 182 and in line with each of the pipes 182b.
[0094] Each of the pipes 182b is connected to a conduit 212 which can be integrated into the shaft 182. The conduits 212 extend axially in the shaft 182 and each of these conduits 212 comprises a downstream end connected to one of the pipes 182b. The upstream ends of the conduits 212 open upstream of the shaft 182 and one of these conduits 212, for example the one visible in section in the figures, is for example connected to the aforementioned actuator 62.
[0095] A first rolling bearing 220 is mounted between the rim 200b of the ring 180 and the downstream end of the shaft 182.
[0096] The bearing 220 is here a rolling bearing and comprises rollers which are arranged between two rolling tracks, respectively internal and external.
[0097] The internal raceway of the bearing 220 is integrated into the shaft 182, that is to say that there is no internal ring attached to the shaft 182 for the bearing 220.
[0098] The outer raceway of the bearing 220 is formed by an outer ring 224 mounted inside the rim 200b. This ring 224 bears axially on a cylindrical bearing surface of the inner periphery of the rim 200b, located upstream. Downstream, the ring 224 is retained axially by a nut 226 screwed to the inner periphery of the rim 200b or a hoop engaged in this rim.
[0099] The internal raceway of the bearing 230 is integrated into the shaft 182, that is to say that there is also no internal ring attached to the shaft 182 for the bearing 230.
[0100] The outer raceway of the bearing 230 is formed by an outer ring 234 mounted inside the rim 200a. This ring 234 bears axially on a cylindrical bearing surface of the inner periphery of the rim 200a, located downstream. Upstream, the ring 234 is retained axially by a nut 228 screwed to the inner periphery of the rim 200a or a hoop engaged in this rim.
[0101] Advantageously, as can be seen in [fig.4], the external surface 182a of the shaft 182 and the internal rolling tracks of the bearings 220 (integrated into the shaft 182) have the same diameter DI and extend without discontinuity in the extension of each other. It is thus understood that the shaft 182 can be mounted inside the ring 180 by axial translation, the ring 180 being able to be pre-equipped with the hoop 204 and the rings 224, 234 and the rollers of the bearings 220, 230 just before this translation.
[0102] A second embodiment of the invention is shown in [fig.5]. This embodiment is very close to the previous embodiment and differs from it essentially in that the external rolling tracks of the bearings 220, 230 are integrated into the ring 180 and it is on the contrary the internal rolling tracks of these bearings which are formed by internal rings 224', 234' mounted on the shaft 182.
[0103] The upstream bearing 230 has an external diameter D3 defined by the raceway integrated into the ring 180, and an internal diameter D3' defined by the internal ring 234'. The downstream bearing 220 has an internal diameter D4 defined by the raceway integrated into the ring 180, and an internal diameter D4' defined by the internal ring 224'.
[0104] In the example shown, D2 is between D3 and D3', and D2 is less than D4 and D4'. Furthermore, D3' < D4' < D3 < D4.
[0105] It can thus be seen that the shaft 182 is stepped and comprises sections of different diameters on which the rings 224', 234' of the bearings 220, 230 are mounted and around which the hoop 204 extends. The shaft 182 comprises an upstream section T1 of smaller diameter D3' for mounting the bearing 230, an intermediate section of diameter D2 for forming the plain bearing P, and a downstream section of diameter D4' for mounting the 220 bearing.
[0106] In the same way, the ring 180 is stepped and comprises sections of different internal diameters in which the bearings 220, 230 and the hoop 204 are mounted. The cylindrical rims 200a, 200b thus have different internal diameters.
[0107] This embodiment makes it possible to reduce the number of tolerance contributors. Consequently, the resulting tolerance on the clearances is greatly reduced by reducing the number of contributors and therefore the resulting clearances are reduced, in particular between the rotor and stator.
[0108] In the example shown in Figures 2 and 5, it can be seen that the blower 12 is driven by a shaft 46 which is guided by bearings 54, 58 and which is coupled to the shaft 182 of the device 174.
[0109] The device 174 of [fig.5] can be mounted in the following manner. The ring 224' and the rollers of the bearing 220 are first mounted on the shaft 182, by axial translation from upstream, until they come into axial abutment on a cylindrical shoulder of the shaft 182. The shaft 182 is then engaged in the ring 180 by axial translation from downstream, until the rollers of the bearing 220 are engaged in the rim 200b of the ring 180. The ring 234' and the rollers of the bearing 230 are then mounted on the shaft 182, by axial translation from upstream, until they come into axial abutment on a cylindrical shoulder of the shaft 182. The rollers of this bearing 230 are then engaged in the rim 200a of the ring 180. Finally, the shaft 46 is mounted on the shaft 182, by axial translation from upstream, until it comes into axial abutment on the internal ring of the bearing 130. The shafts 46, 182 being secured in rotation by sets of complementary splines 46'.Shafts 46, 182 are attached to actuator 62 to supply oil to its chambers.
[0110] The plain bearing P is supplied with oil directly by the pipes 180b of the ring 180. It is understood that the thickness of the space is calculated so that controlled leaks take place at the interfaces between the pipes 180b, 182b, so as to supply the plain bearing P. The oil then spreads over the entire axial extent of the plain bearing P and as far as the rolling bearings 220, 230 for the purpose of lubricating them.
[0111] The radial thickness of the plain bearing is for example between 20 and 40 qm.
[0112] By “path” of the device 174 is meant the association of a pipe 180b of the ring 180 with a pipe 182b of the shaft 182. In the example shown, the device 174 comprises three paths. Preferably, one of the paths is used for the oil supply of the actuator 62, and another of the paths is used for the oil return of the actuator 62. Finally, the last path can be used for the hydraulic protection of the actuator or for supplying oil to the reducer 48.
[0113] In an alternative embodiment not shown, the device could be mounted downstream of the reducer. The shaft of the device would then be coupled in rotation to the carrier. satellites of the reducer for example, in the case where the latter is mobile in rotation.
[0114] The device 174 is for example configured to supply the actuator 62 with an oil pressure of between 2 and 200 bars, and preferably between 5 and 130 bars.
Claims
Claims
1. Fan module for an aircraft turbomachine, this module comprising a fan (12) which comprises a fan shaft (46) and variable-pitch fan blades (12a), and an oil transfer device (174) configured to ensure oil transfer between a stator and an actuator (62) which is rotationally fixed to the fan shaft (46) and which is configured to control the pitch of the fan blades, this device comprising: - a stator ring (180) comprising a first cylindrical surface (180a), for example internal, and internal oil pipes (180b) which each open onto said first cylindrical surface (180a), and - a shaft (182) engaged in or on said ring (180) and comprising a second cylindrical surface (182a) extending inside or around said first cylindrical surface (810a),the shaft comprising internal oil pipes (182b) which each open onto said second cylindrical surface (182a), characterized in that it further comprises: - a plain bearing (P) located between said first and second cylindrical surfaces (180a, 182a), and - rolling bearings (220, 230) mounted between the ring (180) and the shaft (182), on either side of the plain bearing (P), each of these rolling bearings comprising rolling elements between two annular rolling tracks, in that one of the elements chosen from the ring (180) and the shaft (182) carries rings (224, 234, 224', 234') defining first tracks of the rolling bearings, the second rolling tracks of these rolling bearings being integrated into the other of these elements, and in that the plain bearing (P) is produced by a single hoop (204) interposed between the first and second cylindrical surfaces (180a, 182a), and fixed on one of said elements.,
2. Module according to claim 1, in which one of the elements carries the rings (224, 234) of the rolling bearings as well as the hoop (204).
3. Module according to claim 2, in which the hoop has two cylindrical surfaces extending around each other, including a cylindrical hooping surface and a cylindrical centering surface, this cylindrical centering surface having a diameter (Dl) equal to the diameters of the second rolling tracks.
4. Module according to claim 2 or 3, in which the ring (180) carries the rings (224, 234) and the hoop (204).
5. Module according to claim 4, in which the rings (224, 234) of the rolling bearings (220, 230) have identical internal diameters (Dl).
6. Module according to claim 1, in which one of the elements carries the rings (224', 234') and the other of the elements carries the hoop (204).
7. Module according to claim 6, in which the ring (180) carries the hoop (204) and the shaft (182) carries the rings (224', 234').
8. Module according to claim 7, in which the hoop (204) has two cylindrical surfaces extending around each other, including a cylindrical hooping surface on the ring (180) and a cylindrical centering surface on the shaft (182), the rings (224', 234') of the rolling bearings (220, 230) having internal diameters (D3', D4') different from each other and different from the diameter (D2) of the internal cylindrical surface of the hoop (204).
9. Module according to one of the preceding claims, in which the hoop (204) comprises orifices (206) which are on the one hand located opposite the outlets of the pipes (180b, 182b) of one of the elements, and which are in fluid communication with the pipes of the other of the elements by means of annular grooves (208, 210) formed at the outlets of the pipes of this other element.
10. Module according to one of the preceding claims, in which the blower (12) is driven in rotation by a reducer (48), said device being mounted upstream of the reducer and being configured to supply oil to the reducer as well as the actuator, or even also to the reducer.
11. Module according to the preceding claim, in which the blower (12) is driven by a shaft (46) which is guided by rolling bearings (54, 58) and which is coupled to the shaft (182) of the device (174).