Device comprising a bearing with a frangible support and limited footprint

Abstract

A device comprises a central portion (20) and a peripheral portion (22), and at least one bearing (110A) for guiding the central and peripheral portions in rotation relative to each other about an axis (8). The bearing comprises an inner ring (114A) and an outer ring (116A). One of the rings is rigidly connected to a first portion of the central and peripheral portions. The bearing (110A) includes, for rigidly connecting the second ring to the second portion of the central and peripheral portions, an annular row of support webs (115) extending longitudinally, distributed around the axis (8) and circumferentially spaced from each other. The support webs have first radial ends (115A) rigidly connected to the second ring and second radial ends (115B) rigidly connected to the second portion. The support webs (115) thus define a frangible support for the second ring.Figure for the abbreviation: Figure 1.

Description

Title of the invention: Device comprising a bearing with frangible support and limited space requirement Technical field

[0001] The present invention relates to the field of guiding two elements in rotation relative to each other by means of a bearing.

[0002] The present invention is the result of technological research conducted by the Applicant, aimed at significantly improving the performance of aircraft and, in this sense, contributing to reducing their environmental impact. State of the prior art

[0003] Bearings, whether plain or rolling, are widely used in devices comprising two elements which need to be guided in rotation relative to each other, for example a rotor element and a stator element.

[0004] In the event of seizure of such a bearing, a torque along the axis of rotation risks being transmitted between the two concentric rings of the bearing and therefore between the two elements via the bearing, which may in certain cases cause damage which it would be desirable to avoid.

[0005] This is particularly the case for bearings equipping fluid transfer devices designed to transfer several fluid paths from a fixed reference point to a rotating reference point, or more generally between two reference points in relative rotation with respect to each other, such reference points being in practice defined by parts or assemblies of parts.

[0006] In the field of turbomachines intended for aircraft propulsion, the fixed reference of such a device may be defined by a stator of such a turbomachine while the rotating reference may be defined by a rotor thereof. In such applications, the fluid is for example oil or another fluid intended for the hydraulic control of actuators. In particular applications, such a device, of the type commonly called OTB (from the English terminology "Oil Transfer Bearing"), is intended to supply a cylinder controlling the pitch of blades of one or more propellers as well as an actuator for securing the blades.

[0007] Bearings of the fluid film damped type, one of the rings of which is supported by an offset flexible structure, commonly called a "squirrel cage", are well known. Such a structure has the particularity of breaking if a sufficiently high torque is applied to it.

[0008] However, it is also generally desirable to limit as much as possible the mass and size of such devices, which is not possible with the aforementioned remote flexible structures.

[0009] Furthermore, these structures, designed to give one of the rings of such a bearing the radial freedom necessary for damping by fluid film, are not suitable in cases where such radial freedom is not desired. Statement of the invention

[0010] The subject of the invention is a device comprising a bearing making it possible to limit the risks of damage in the event of the latter seizing, and the mass and size of which can be limited.

[0011] The invention also relates to a device comprising a bearing whose rings are rigidly connected to the elements, hereinafter referred to as the central part and peripheral part, the bearing of which allows guidance in relative rotation.

[0012] The invention proposes for this purpose a device comprising a central part and a peripheral part and at least one bearing for guiding the central and peripheral parts in rotation relative to each other along an axis, the bearing comprising an inner ring and an outer ring, a first of said rings being rigidly connected to a first part among said central and peripheral parts, and in which the bearing comprises, to rigidly connect the second of said rings to the second part among said central and peripheral parts, an annular row of support webs extending longitudinally while being distributed around the axis and spaced circumferentially from each other, the support webs having respective first radial ends rigidly connected to the second ring and respective second radial ends rigidly connected to the second part.

[0013] The support sails intrinsically offer good resistance to radial forces but limited resistance to circumferential forces, which result, for each of the sails, in shear forces.

[0014] The support webs thus allow a rigid connection of the relevant ring of the bearing to the corresponding part of the device when the latter is operating normally, while allowing a cessation of this rigid connection by their rupture in the event of a sufficiently high applied torque, as is the case in a seizure situation. In this sense, the support webs define a frangible support for the relevant ring of the bearing.

[0015] In preferred embodiments, the support sails extend along planes containing the axis.

[0016] In preferred embodiments, the support sails are made of a material in which at least one of the second part and the second ring is made.

[0017] In preferred embodiments, the second ring is the outer ring of the bearing.

[0018] In preferred embodiments, the device comprises an annular row of rolling elements interposed between the inner ring and the outer ring.

[0019] In preferred embodiments, the central portion has an external surface with a geometry of revolution along an axis.

[0020] In preferred embodiments, the peripheral part has an internal surface with a geometry of revolution along the axis arranged around the external surface of the central part with the ability to rotate relative to the latter along the axis.

[0021] In preferred embodiments, transfer chambers are defined between the outer surface of the central portion and the inner surface of the peripheral portion.

[0022] In preferred embodiments, the central portion defines first fluid paths respectively connecting fluid inlets of the device to the transfer chambers through said external surface.

[0023] In preferred embodiments, the peripheral portion defines second fluid paths respectively connecting fluid outlets of the device to the transfer chambers through said internal surface.

[0024] In preferred embodiments, the device is configured to transfer multiple fluid paths between the fluid inlets and the fluid outlets.

[0025] The invention also relates to a turbomachine comprising at least one device of the type described above, and comprising a stator secured to one of the central and peripheral parts of the device and a rotor secured to the other of the central and peripheral parts of the device.

[0026] The invention also relates to a method for implementing a device of the type described above, comprising the breaking of the support webs under the effect of a torque along the axis applied by one of the central and peripheral parts to the annular row of support webs in the event of seizure of the bearing.

[0027] Where appropriate, the method comprises: • the selective supply of fluid to the first fluid paths, via the fluid inlets of the device; • the circulation of the fluid in the first fluid paths up to the transfer chambers; • the circulation of the fluid in the second fluid paths from the transfer chambers to the fluid outlets of the device. Brief description of the drawings

[0028] The invention will be better understood, and other details, advantages and characteristics thereof will appear on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

[0029] [Fig-1] is a schematic cross-sectional view of a device according to the invention;

[0030] [Fig.2] is a schematic axial sectional view of a device such as that of the [Fig.l], configured for the transfer of several fluid paths;

[0031] [Fig.3] is a schematic perspective view of a central part of the device of [Fig.2];

[0032] [Fig.4A] is a schematic axial sectional view of the central part of [Fig.3];

[0033] [Fig.4B] is a schematic cross-sectional view of the central part of the [Fig.3], according to the IVB-IVB plan of [Fig.4A];

[0034] [Fig.5] is a schematic axial sectional view of a peripheral part of the device of [Fig.2];

[0035] [Fig.6] is a schematic perspective and axial sectional view of the peri-part spherical, and bearings, of the device of [Fig.2];

[0036] [Fig.7] is a schematic axial sectional view of a sleeve of the peri-part spherical of the device of [Fig.2];

[0037] [Fig.8] is a schematic perspective and axial sectional view of a fret of the peripheral part of [Fig.5];

[0038] [Fig.9] is a flowchart of a method of manufacturing a device such as that of [Fig.2];

[0039] [Fig.10A] is a schematic axial sectional view of the rings of the peripheral part, illustrating a step in the manufacturing process of [Fig.9];

[0040] [Fig.lOB] is a view similar to [Fig.lOA], illustrating another step in the manufacturing process of [Fig.9];

[0041] [Fig.10] is a view similar to [Fig.7], illustrating a step in the manufacturing process of [Fig.9];

[0042] [Fig.10D] is a view similar to [Fig.8], illustrating a step in the manufacturing process of [Fig.9];

[0043] [Fig. 11] is a view similar to [Fig.2], illustrating the implementation of the device;

[0044] [Fig. 12] is a schematic axial sectional view of a turbomachine comprising a device such as that of [Fig.l] or that of [Fig.2].

[0045] Throughout these figures, identical references may designate identical or similar elements. Detailed disclosure of preferred embodiments

[0046] [Fig. 1] illustrates, in general, a device 10 comprising a central part 20 and a peripheral part 22, and at least one bearing 110A for guiding the central 20 and peripheral 22 parts in rotation relative to each other along an axis 8. In typical applications, one of the parts is integral with a stator while the other part is integral with a rotor, for example within a turbomachine, as will appear more clearly in the following.

[0047] In the present description, the axial direction X is the direction of the axis 8. The radial direction R is at all points a direction orthogonal to the axis 8 and passing through the latter, and the orthoradial or circumferential direction C is at all points a direction orthogonal to the radial direction R and to the axis 8. A transverse plane is a plane orthogonal to the axis 8. In the absence of any indication to the contrary, the terms “internal” and “external” refer respectively to a relative proximity, and a relative distance, of an element with respect to the axis 8.

[0048] The bearing 110A comprises an inner ring 114A and an outer ring 116A. A first of said rings, for example the inner ring 114A, is rigidly connected to a first part among the central and peripheral parts, in this case the central part 20, for example by being mounted tightly around the latter.

[0049] To rigidly connect the second of said rings, in this case the outer ring 116A, to the second part among said central and peripheral parts, in this case the peripheral part 22, the device comprises an annular row of support webs 115 extending longitudinally, that is to say parallel to the axis 8, being distributed around the axis 8 and spaced circumferentially from each other.

[0050] The support sails 115 have respective first radial ends 115A rigidly connected to the second ring or outer ring 116A, and respective second radial ends 115B rigidly connected to the second part or peripheral part 22.

[0051] The support sails 115 can be produced by prior machining of the second ring or external ring 116A, or be welded to the latter by their first radial ends 115A.

[0052] The support webs 115 may be fixed to the second portion or peripheral portion 22 by welding their second radial ends 115B to the latter. Alternatively, the second radial ends 115B of the support webs 115 may be rigidly connected to an intermediate ring, itself mounted tightly in the second portion or peripheral portion 22, for example by shrink fitting. As a further variant, the second ring or outer ring 116A, the support webs 115, and such an intermediate ring, may be produced in a single piece, for example by means of an additive manufacturing technique.

[0053] The support webs 115 allow a rigid connection between the second ring or external ring 116A and the second part or peripheral part 22, in particular with respect to radially oriented forces in operation, while offering less resistance to circumferentially oriented forces.

[0054] With appropriate dimensioning, as will be understood by those skilled in the art, the support webs 115 thus have the ability to break when a torque is applied to them along the axis 8, typically resulting from a seizure situation. of the bearing. The breaking of the support webs 115 makes it possible, in such a situation, to prevent the rotating part 20 or 22 from exerting a torque on the other part and thus damaging the latter.

[0055] The annular row of support sails 115 also has the advantage of good compactness and requires a limited quantity of material, and can therefore involve a limited mass, in particular in comparison with the squirrel cages of known devices.

[0056] The support webs 115 preferably extend along planes containing the axis 8, i.e. axial-radial planes. The resistance of the support webs 115 to radial forces is thus maximized, because such radial forces stress the support webs 115 in tension or compression, while the resistance of the support webs 115 to circumferential forces is thus minimized, because such circumferential forces stress the support webs 115 in shear.

[0057] In addition, the support webs 115 are advantageously made of the same material as the second part or peripheral part 22, for example titanium, in order to limit the differential thermal expansions between these elements. Alternatively, the support webs 115 may be made of the same material as the second ring or external ring 116A, or even of a material different from the materials constituting the second part and the second ring.

[0058] The bearing 110A is for example a rolling bearing. In the example illustrated, the bearing 110A thus comprises an annular row of rolling elements 118, such as balls.

[0059] A device such as the device 10 of [Fig. 1] is described below, with reference to Figures 2 to 11, in the context of a particular application to the transfer of fluid within a turbomachine intended for the propulsion of an aircraft, in which such a device is particularly advantageous due to its mass and its reduced size. In this respect, [Fig. 1] can be considered as a simplified version of a section along plane II of [Fig. 2]. The invention is nevertheless not limited to this particular application. I. General information

[0060] [Fig. 2] illustrates such a device 10, intended for the transfer of several fluid paths between two reference points rotating relative to each other, for example between a turbomachine stator, defining a fixed reference point, and a turbomachine rotor, defining a reference point rotating along the axis 8. In the example described, there are three fluid paths, but the principles described below are of course applicable regardless of the number of fluid paths.

[0061] The stator comprises for example a three-way fluid supply plate 12 ([Fig.2]), intended to be connected to fluid inlets 14A-14C of the device ( [Fig. 3]), while the rotor comprises fluid receiving means (not shown) intended to be connected to fluid outlets 16A-16C of the device ([Fig. 6]). Although the present description provides, for convenience, a direction of circulation of fluid from the fluid inlets to the fluid outlets through the device 10, a reverse direction of circulation is possible without departing from the scope of the invention. In this regard, the terms "inlet" and "outlet" must be considered, throughout the present application, as synonymous with passage orifices or "fluid ports".

[0062] Still with reference to [Fig. 2], the device 10 comprises, in general, the central part 20 (also visible, alone, in Figures 3 and 4A-4B), and the peripheral part 22 (also visible, alone, in Figures 5 and 6) arranged around the central part 20 with the ability to rotate relative to the latter along the axis 8.

[0063] The central part 20 is for example intended to be integral with the stator, while the peripheral part 22 is for example intended to be integral with the rotor. In other application examples, the roles of the central part 20 and peripheral part 22 can be reversed, the central part then being integral with a rotor and the peripheral part being integral with a stator.

[0064] The central part 20 has an external surface 20A with a geometry of revolution along the axis 8, and preferably of cylindrical shape. The peripheral part 22 has an internal surface 22A with a geometry of revolution along the axis 8, arranged around the external surface 20A of the central part 20, and preferably of a shape generally similar to the shape of the external surface 20A apart from a homothetic transformation, the two surfaces being able to further differ by the presence of different annular orifices and grooves as will appear more clearly in the following. The internal surface 22A of the peripheral part 22 can be jointly constituted by several parts 50, 70A, 70B, 90 belonging to the peripheral part 22, as will appear more clearly in the following.

[0065] An annular space 23 ([Fig.2]) is defined between the external surface 20A of the central part 20 and the internal surface 22A of the peripheral part 22.

[0066] Generally, the annular space 23 comprises, arranged axially alternately, first annular regions defining transfer chambers 24A-24C, and second annular regions 26A-26D, with a restricted cross-section compared to the transfer chambers 24A-24C, to separate the latter, on the one hand, from each other, and, on the other hand, from the outside of the annular space 23. Thus, a second annular region 26B, 26C is arranged between any pair of consecutive transfer chambers 24A-24B and 24B-24C, and second annular regions 26A, 26D are arranged respectively at two opposite axial ends of the annular space 23. Due to their relatively restricted cross-section, the second annular regions 26A-26D have the function of limiting and controlling the fluid leaks between the central portion 20 and the peripheral portion 22 from the transfer chambers 24A-24C.

[0067] For each of the fluid paths to be transferred, the central part 20 comprises a fluid path in fluid communication with a corresponding fluid path within the peripheral part 22, in order to allow circulation of the fluid of the path considered from a corresponding fluid inlet 14A-14C secured to the central part (figures 2 and 3), to a corresponding fluid outlet 16A-16C secured to the peripheral part (figures 2 and 5). In addition, the two-by-two communication between the fluid paths of the central part 20, called first fluid paths in the following and referenced FP1A-FP1C ([Fig.4A]), and the fluid paths of the peripheral part 22, called second fluid paths in the following and referenced FP2A-FP2C ([Fig.5]), is implemented via the annular transfer chambers 24A-24C ([Fig.2]) defined between the external surface 20A of the central part 20 and the internal surface 22A of the peripheral part 22, as will appear more clearly in the following. Each first fluid path FP1A-FP1C therefore connects a corresponding fluid inlet 14A-14C to a corresponding transfer chamber 24A-24C, while each corresponding second fluid path FP2A-FP2C connects the corresponding transfer chamber 24A-24C to the corresponding fluid outlet 16A-16C.

[0068] The fluid inlets 14A-14C are preferably arranged at a longitudinal end of the device located on a first axial side S1, while the fluid outlets 16A-16C are preferably arranged at a longitudinal end of the device located on a second opposite axial side S2. The fluid inlets and outlets may, in other embodiments, be arranged on the same side. II. Central part

[0069] The central part 20 (figures 2-4B) comprises a main portion 30 defining the aforementioned external surface 20A, and, at one end thereof located on the first axial side S1, a connecting portion 32, and at another end thereof located on the second axial side S2, a journal 34. The journal 34 is for example separated from the external surface 20A by a shoulder 35A, while the external surface 20A is separated from the connecting portion 32 by a shoulder 35B.

[0070] To define the first fluid paths FP1A-FP1C, the main portion 30 generally comprises corresponding fluid channels 36A-36C, respectively connected, on the first axial side S1, to the fluid inlets 14A-14C, and for each of the fluid channels 36A-36C, at least one fluid tapping 38A-38C connected to the fluid channel 36A-36C in question, on the second axial side S2, and opening through the external surface 20A.

[0071] The fluid channels 36A-36C are concentric channels extending along axis 8. The aforementioned external surface 20A surrounds all of these fluid channels 36A-36C.

[0072] Thus, the main portion 30 comprises, for example, a first channel 36A with a circular cross-section (i.e., disc-shaped) centered relative to the axis 8, a second channel 36B with a ring-shaped cross-section, extending around the first channel 36A, and a third channel 36C also with a ring-shaped cross-section, extending around the second channel 36B ([Fig.4B]).

[0073] On the side of the journal 34, that is to say on the second axial side, the channels 36A-36C have ends 39A-39C staggered along the axis 8 ([Fig.4A]) so that the further a channel is located from the axis 8, the less it extends towards the second axial side S2 (and, in this case, the shorter this channel is). Thus, the first channel 36A is the one of the channels which extends the furthest towards the journal 34 while the third channel 36C is the one of the channels which extends the least far towards the journal 34.

[0074] In the preferred example illustrated, the main portion 30 comprises, for each fluid channel 36A-36C, a corresponding series of fluid tappings 38A-38C each having an internal end connected to the channel 36A-36C in question and an external end opening through the external surface 20A. The fluid tappings of each series 38A-38C thus start from the corresponding channel 36A-36C.

[0075] For this purpose, the taps 38A of a first series, which connect the external surface 20A to the first channel 36A, are arranged beyond the second channel 36B in the direction of the journal 34. Similarly, the taps 38B of a second series, which connect the external surface 20A to the second channel 36B, are arranged beyond the third channel 36C in the direction of the journal 34. More generally, for each of the channels 36A-36C, the tap(s) connected to it extend(s) beyond any other channel formed around the channel in question, in the direction of the second axial side S2.

[0076] The taps 38A-38C of each series are for example arranged in the form of an annular row of taps regularly distributed around the axis 8. The taps 38A-38C preferably each extend in the radial direction R.

[0077] The connection portion 32 comprises fluid connection means 40A-40C ([Fig. 3]) respectively dedicated to the different fluid paths and having respective first ends (two of which, 42A and 42B, are visible in [Fig. 4A]) opening respectively into the channels 36A-36C, and respective second ends ([Fig. 3]) defining the fluid inlets 14A-14C of the device and intended to be connected to corresponding connection means on the fluid supply plate 12 ([Fig. 2]). More precisely, each second end forms for example a connection plug adapted to be connected to a corresponding plug on the fluid supply plate 12.

[0078] The configuration of concentric fluid channels 36A-36C associated with the tappings 38A-38C corresponding to the device 10 make it possible to limit in a particularly effective manner the size of the central part 20 and the number of parts constituting the device 10.

[0079] In addition, the concentricity of the fluid channels 36A-36C makes it possible to limit the deformations of the central part 20 due to the pressure of the fluid in the first fluid paths FP1A-FP1C in operation. The central part 20 can thus have a lightweight design without this harming the general operation of the device 10.

[0080] Alternatively, the first fluid paths FP1A-FP1C may be constituted in a manner different from that described above. III. Peripheral part

[0081] The peripheral part 22 (visible in [Fig. 2] and, in more detail, in figures 5 and 6) generally comprises a sleeve 50 or main body, rings 70A, 70B, and a hoop 90, rigidly assembled to each other. IILA Sleeve

[0082] With reference to [Fig.7], the sleeve 50 (shown isolated from the rest of the device) has an internal surface with a geometry of revolution, for example substantially cylindrical, delimiting a bore 52 extending along the axis 8, and an external surface 54 also with a geometry of revolution, for example substantially cylindrical.

[0083] The bore comprises two end portions 52A, 52B of annular shape and, between the latter, an intermediate portion 52C also of annular shape, of smaller cross-section than that of the end portions 52A, 52B. The internal surface which delimits the bore 52 thus has two shoulders 52D, 52E axially delimiting between them the intermediate portion 52C.

[0084] The sleeve 50 further comprises an annular rib 56 formed in radially inward projection in the intermediate portion 52C of the bore and thus dividing the latter into a first part 52C1 located on the second axial side S2 and a second part 52C2 located on the first axial side SL. The annular rib 56 has an internal end surface 58 with a revolution geometry, for example cylindrical, which contributes to delimiting the intermediate portion 52C of the bore between the first and second parts 52C1, 52C2.

[0085] The sleeve 50 has a threaded external surface 60 at one of its axial ends, for example that located on the first axial side SI, and a radial annular flange 62 at its opposite axial end.

[0086] To help define each of the second fluid paths FP2A-FP2C, the sleeve 50 comprises at least one corresponding fluid passage 64 for each second fluid path, and preferably a corresponding series of such fluid passages 64 for each second fluid path. These fluid passages 64 each have an inner end opening through the inner surface of the sleeve 50 in the intermediate portion 52C of the bore, and an outer end opening through the outer surface 54 of the sleeve.

[0087] In the illustrated example which concerns a device with three fluidic channels, the aforementioned fluidic passages are divided for example into a first series 64A of fluidic passages opening into the first part 52C1 of the intermediate portion of the bore, a second series 64B of fluidic passages opening through the internal end surface 58 of the annular rib 56, and a third series 64C of fluidic passages opening into the second part 52C2 of the intermediate portion of the bore.

[0088] In particular, the fluid passages of the second series 64B open into the transfer chamber 24B ([Fig.2]). mB Rings

[0089] The rings 70A, 70B (visible in [Fig. 2] and, in more detail, in FIGS. 5 and 6), which are for example two in number, have respective external surfaces 72 mounted tightly in the bore 52, in this case in the first and second parts 52C1, 52C2 of the intermediate portion 52C of the bore.

[0090] The rings 70A, 70B have respective internal surfaces 74 which, according to the terminology adopted in the present description, form corresponding parts of the internal surface 22A of the peripheral part.

[0091] In the example illustrated, the rings 70A, 70B have respective flanks 75B, 75C (FIGS. 5 and 6) applied respectively against two opposite flanks 56A, 56B of the annular rib 56. Thus, the internal end surface 58 of the annular rib 56, which is axially interposed between the internal surfaces 74 of the rings, defines jointly with the latter the internal surface 22A of the peripheral part.

[0092] The use of such rings 70A, 70B to partially define the internal surface 22A of the peripheral portion 22 generally makes it possible to facilitate the operations of grinding the internal surface 22A and / or the operations of depositing a protective coating on the latter, by dividing the latter into several sections which can be treated independently of one another. Each ring 70A, 70B in fact has a smaller axial extent compared with the total axial extent of the internal surface 22A, so that certain grinding tools and certain tools intended to spray protective coatings, which would be unsuitable for treating the internal surface 22A in its entirety due to the axial extent of the latter, can instead be used to treat the internal surface 74 of each ring 70A, 70B taken individually, as well as, in the example illustrated, the internal end surface 58 of the annular rib 56. In the absence of the rings, access to the latter is in fact also facilitated due to the larger internal diameter of the first and second parts 52C1, 52C2 of the intermediate portion 52C of the bore 52, compared with the internal diameter of the internal surface 22A.

[0093] Obtaining a particularly reduced clearance between the surfaces 20A and 22A is thus made possible. This results in the possibility of obtaining a satisfactory seal between the central 20 and peripheral 22 parts even in cases where the overlap length, that is to say the axial extent of the annular space 23 defined between these parts, would be relatively small in comparison with what is necessary in devices not using such rings. However, the reduction in the overlap length required to obtain a satisfactory seal offers in particular the advantage of a reduced mass and a reduced size with regard to the device 10.

[0094] To help define some of the second fluid paths FP2A-FP2C, each ring 70A, 70B comprises fluid passages 76A, 76B each having an inner end 78 opening, through the inner surface 74 of the ring, into a corresponding transfer chamber 24A, 24C. The inner surface 74 of each ring 70A, 70B defines two sealing tracks 79A, 79B, of annular shape, for example cylindrical, arranged axially on either side of the fluid passages 76A, 76B of the ring in question. These sealing tracks 79A, 79B are provided to extend a short distance from the outer surface 20A of the central part 20 and thus limit axial leaks of fluid from the corresponding transfer chamber 24A, 24C ([Fig.2]).

[0095] To define the transfer chambers 24A-24C, the internal surfaces 74 of the rings 70A, 70B and the internal end surface 58 of the annular rib 56 each form a corresponding annular groove 80A, 80B, 80C (FIGS. 5 and 6), into which the corresponding fluid passages 76A, 64B, 76B open. The annular groove 80A, 80C of each ring is thus defined between the sealing tracks 79A, 79B of the ring in question. Alternatively or additionally, the transfer chambers 24A-24C may be defined by annular grooves formed on the external surface 20A of the central portion 20.

[0096] The aforementioned second annular regions 26A-26D are thus respectively delimited externally by the sealing tracks 79A, 79B of each of the rings 70A, 70B.

[0097] A compressible annular sealing gasket 82 projects from a groove formed in the aforementioned flank 75B, 75C of each of the rings 70A, 70B, in the direction of the annular rib 56, so as to bear against the flanks 56A, 56B of the latter and thus avoiding fluid leaks between each ring 70A, 70B and the rib 56. Alternatively or additionally, grooves for the seals 82 may be respectively formed in the flanks 56A, 56B of the rib 56.

[0098] Furthermore, the fluid passages 76A of the ring 70A each have an external end 84 opening through the external surface 72 of the ring 70A, opposite the first series 64A of fluid passages of the sleeve 50 (i.e. axially at the same level as this series 64A of fluid passages). Similarly, the fluid passages 76B of the ring 70B each have an external end 84 opening through the external surface 72 of the ring 70B, opposite the third series 64C of fluid passages of the sleeve 50.

[0099] To allow fluid circulation between the passages 76A, 76B of the rings 70A, 70B and the corresponding passages 64A, 64C of the sleeve, annular distribution cavities 86A, 86B are defined by grooves formed in the surface of the sleeve 50 which delimits the bore 52 so that the aforementioned passages open into these distribution cavities 86A, 86B. Alternatively or in a complementary manner, the distribution cavities 86A, 86B may be defined by grooves formed in the external surfaces 72 of the rings 70A, 70B.

[0100] A compressible annular sealing gasket 88A, 88B is interposed between each ring 70A, 70B and the sleeve 50, on an axial side opposite the annular rib 56 relative to the corresponding distribution cavity 86A, 86B, to limit fluid leaks out of the intermediate portion 52C of the bore.

[0101] Each of the annular sealing joints 88A, 88B projects, for example, from a groove formed in the external surface 72 of each of the rings 70A, 70B, so as to bear against the internal surface of the sleeve 50 delimiting the bore 52. As a variant or in a complementary manner, such a groove may be formed, for each joint 88A, 88B, in the internal surface of the sleeve 50.

[0102] In order to reduce the mass of the device as much as possible, the opposite flanks 75A, 75B and 75C, 75D of the rings 70A, 70B have recesses 89. The rings thus have, for example, an axial half-section forming a radial median portion, in which the corresponding fluid passages are formed, and two axial annular heels each extending in projection towards the first axial side and towards the second axial side, respectively from each of the radial ends of the median portion of the ring in question.

[0103] Alternatively, the number of rings may be greater than two.

[0104] In addition, the sleeve 50 may be devoid of the annular rib 56, in which case the entire internal surface 22A of the peripheral portion may be defined by the rings.

[0105] In the terminology adopted in the present description, the assembly consisting of the sleeve 50 and rings 70A, 70B constitute a transfer sleeve DT ([Fig.5]). Thus, the transfer sleeve DT and the hoop 90 together constitute the peripheral part 22.

[0106] Alternatively, the transfer sleeve DT may be formed in one piece. In other words, the device 10 may be devoid of the rings 70A, 70B, in which case the sleeve 50 is devoid of the rib 56 and defines the entirety of the internal surface 22A of the peripheral portion. IIIC. Fret

[0107] The hoop 90 (visible in figures 2, 5 and 6, and shown isolated from the device in [Fig.8]) has an internal surface 92A, with a geometry of revolution, for example cylindrical or, more generally, of a shape substantially complementary to the shape of the external surface 54 of the sleeve 50, and also called the hoop interface surface in the following.

[0108] The hoop 90 is mounted with a sliding fit around the sleeve 50, or more generally around the transfer bushing DT, so that the inner surface 92A of the hoop, or hoop interface surface, surrounds the outer surface 54 of the sleeve, or bushing interface surface, being in tight contact with the latter.

[0109] The hoop 90 comprises fluid conduits defining, in the terminology of the invention, redirection fluid paths RFP-A to RFP-C ([Fig.8]), which each constitute a part of a second corresponding fluid path FP2A-FP2C within the hoop 90. In the illustrated example, each redirection fluid path RFP-A to RFP-C is defined by a corresponding pair of diametrically opposed fluid conduits 94A, 94B, 94C.

[0110] Each fluid conduit 94A, 94B, 94C has a first end 96A-96C ([Fig.8]) opening through the internal surface 92A of the hoop, preferably opposite a corresponding series 64A-64C of the fluid passages 64 (figures 2, 5 and 6) defined in the sleeve 50 (that is to say axially at the same level as this series of fluid passages).

[0111] To allow fluid circulation between the fluid passages 64 of the sleeve 50 and the fluid conduits 94A-94C of the hoop 90, annular distribution cavities 98A-98C are provided in the form of grooves formed in the outer surface 54 of the sleeve so that the outer ends of the fluid passages 64 and the first ends 96A-96C of the fluid conduits 94A-94C open into these distribution cavities 98A-98C (FIGS. 5 and 6). Alternatively or additionally, grooves may be formed in the inner surface 92A of the hoop to define the distribution cavities 98A-98C.

[0112] The sealing of the distribution cavities 98A-98C is for example ensured by means of compressible annular sealing gaskets 100 interposed between the external surface 54 of the sleeve and the internal surface 92A of the hoop, axially on either side of each of the distribution cavities 98A-98C. To best limit the risks of damage to the seals 100 during assembly and disassembly operations of the device, the external surface 54 of the sleeve and the internal surface 92A of the hoop advantageously have a stepped shape resulting in a slightly decreasing diameter after each of the distribution cavities 98A-98C, in the direction going from the second axial side S2 towards the first axial side SI.

[0113] Each of the annular sealing gaskets 100 projects, for example, from a groove formed in the external surface 54 of the sleeve 50, so as to bear against the internal surface 92A of the hoop. Alternatively or additionally, such a groove may be formed, for each gasket 100, in the internal surface 92A of the hoop.

[0114] Furthermore, each fluid conduit 94A, 94B, 94C has a second end 102A-102C, opposite the first end 96A-96C, arranged at an axial end of the hoop 90, for example located on the second axial side ([Fig.8]). The respective second ends 102A-102C of the conduits (in this case of each pair of conduits) define the corresponding fluid outlets 16A-16C of the device 10.

[0115] Each of the fluid conduits 94A-94C has, for example, a bent shape ( [Fig.8]). Thus, each conduit 94A-94C has a radial portion 104A-104C forming, at an internal end, the aforementioned first end 96A-96C of the conduit, and connected, at an external end, to an axial portion 106A-106C of the conduit ending in the second end 102A-102C of the conduit. The radial portions 104A-104C of the different pairs of conduits are axially staggered, like the series 64A-64C of fluid passages of the sleeve 50. The axial portions 106A-106C of the conduits are for example defined within corresponding ribs 107A-107C, formed to project radially outward from an external surface 92B of the hoop, and extending longitudinally.

[0116] Furthermore, the hoop 90 is rigidly connected to the sleeve 50 by being sandwiched between the radial annular flange 62 of the sleeve 50, on the second axial side S2, and a nut 108 screwed onto the threaded external surface 60 of the sleeve 50 against an axial end 90A of the hoop, on the first axial side SI (figures 5 and 6).

[0117] In the illustrated example, the second ends 102A of the pair of fluid conduits 94A open out through passage orifices formed in the radial annular flange 62 of the sleeve 50.

[0118] The fact of splitting the peripheral part 22 into the transfer sleeve DT and the hoop 90 makes it easier to drill the transfer fluid paths, in this case the drilling of the fluid passages 64 of the sleeve 50. In fact, these can be drilled radially through the transfer sleeve DT, in this case the sleeve 50, from the outside of this sleeve, by placing a drilling tool in facing the sleeve interface surface 54, without it being necessary to subsequently plug the radially external end of these transfer fluid paths (or passages 64) since this external end is intended to be connected to the conduits 94A-94C of the hoop 90. These conduits can be easily produced, including their first ends 96A-96C and, where appropriate, their radial portions 104A-104C, because the internal diameter of the hoop is larger than that of the bore 52, which makes it possible to pass a radial drilling tool from the inside of the hoop 90.

[0119] In the terminology adopted in the present description, the assembly consisting of the sleeve 50 and the hoop 90 constitutes a receiving sleeve DR ([Fig.5]). This receiving sleeve DR therefore defines the bore 52. Thus, the receiving sleeve DR and the rings 70A, 70B together constitute the peripheral part 22.

[0120] Alternatively, the receiving sleeve DR may be formed in one piece. In an embodiment in which the peripheral portion 22 does not include the hoop 90 or the rings 70A, 70B, the sleeve 50 alone defines the second fluid paths FP2A-FP2C.

[0121] IV. Connection between central and peripheral parts

[0122] With reference to figures 2 and 5, the central 20 and peripheral 22 parts are connected by being guided in rotation relative to each other by means of at least one bearing such as the bearing 110A described above, radially interposed between the central part 20 and the peripheral part 22, in this case by means of two similar bearings 110A and 110B.

[0123] As explained above with reference to [Fig. 1], each bearing 110A, 110B allows a rigid connection between one of its rings, for example the external ring 116A, 116B, and one of the parts, in this case the peripheral part 22, in normal operation, and allows a break in this connection in the event of seizure so as to avoid or at least limit the risks of damage to the part 20 linked to the stator by the part 22 linked to the rotor.

[0124] In addition, each of the bearings 110A, 110B is advantageously housed in a respective enclosure 112A, 112B in fluid communication with a corresponding second annular region 26A, 26D among the aforementioned second annular regions of the annular space 23.

[0125] Such an arrangement makes it possible to lubricate each bearing by means of fluid leaks from the transfer chambers 24A-24C and passing through the corresponding second annular region 26A, 26D, into the enclosure 112A, 112B of the bearing. The flow rate of such leaks is determined in particular by the cross-section of the second annular regions 26A-26D.

[0126] Although conceivable within the framework of the present disclosure, the use of dis positive spraying or injection of lubricant towards the bearings can thus be avoided, which has the advantage in particular of a corresponding reduction in the mass and size of the device 10 and, where appropriate, of the turbomachine which would be equipped with it.

[0127] In the example illustrated, the inner rings 114A, 114B and outer rings 116A, 116B of each bearing delimit a region 120 of the enclosure 112A, 112B in fluid communication with the corresponding second annular region 26A, 26D and in which the annular row of rolling elements 118 of the bearing is housed.

[0128] In addition, the bearings 110A, 110B are arranged axially on either side of the annular space 23, so that the enclosures 112A, 112B are axially adjacent to the second annular regions 26A, 26D respectively. In particular, the bearings 110A, 110B are respectively arranged in the end portions 52A, 52B of the bore 52 of the sleeve 50.

[0129] The bearings 110A, 110B are advantageously of the oblique contact type and arranged in an “O” arrangement.

[0130] With reference to [Fig.2], the bearing 110B, located on the first axial side SI, is for example arranged so that its inner ring 114B is axially in abutment, on the first axial side SI, against the shoulder 35B which is formed at one end of the outer surface 20A of the central part 20 located on the first axial side SI, and so that the shoulder 52E of the sleeve 50 is axially in abutment, on the first axial side SI, against the outer ring 116B of the bearing.

[0131] The bearing 110A, located on the second axial side S2, is for example arranged so that its inner ring 114A is mounted on the journal 34 of the central part 20 and its outer ring 116A is axially in abutment, in the direction of the first axial side S1, against the shoulder 52D of the sleeve 50. In addition, a nut 122 is screwed onto the journal 34 of the central part 20 so as to be axially in abutment, in the direction of the first axial side S1, against the inner ring 114A of this bearing. A shim 124 is advantageously interposed between the inner ring 114A and the shoulder 35B arranged at the end of the outer surface 20A located on the second axial side S2. Such a shim 124 can be specifically machined or ground during assembly operations of the device 10 in order to compensate for the manufacturing tolerances of the various constituents of the latter in the axial direction and guarantee a determined axial preload of the bearings 110A, 110B.

[0132] Of course, a gap is advantageously maintained between each ring 70A, 70B and the bearing 110A, 110B adjacent to it, or more generally between the transfer sleeve DT and each bearing 110A, 110B, to allow the circulation of the fluid, coming from the annular space 23, into the enclosure 112A, 112B of each bearing. V. Manufacturing method

[0133] With reference to [Fig.9], a method of manufacturing the device 10 of [Fig.2] generally comprises the steps of: A) providing the central part 20 and the peripheral part 22; then B) mounting the peripheral part 22 around the central part 20 so as to allow relative rotation between these two parts and to put the first fluid paths and the second fluid paths into communication two by two.

[0134] Step A may comprise a step A1 of manufacturing the central part 20 by means of an additive manufacturing method, in particular of the powder bed fusion type by laser beam, or by means of a foundry method, in particular of the lost wax type using soluble cores to constitute the fluidic channels of the central part 20.

[0135] Step A may comprise a step A2 consisting of: A2a) providing the receiving sleeve DR and the rings 70A, 70B; A2b) grinding the internal surface 74 of each of the rings 70A, 70B according to the geometry of the external surface 20A of the central part 20 by means of a grinding tool 125 ([Fig.10A]); then A2c) optionally, apply a protective coating to the internal surface 74 of each of the rings 70A, 70B by spraying using a spraying tool 126 ([Fig.10B]) for example configured to spray a fluid intended to form the coating at an incidence of approximately 45 degrees on the internal surface 74; then A2d) fitting the rings 70A, 70B tightly into the bore 52 so that the inner surface 74 of each of the rings 70A, 70B contributes to forming the inner surface 22A of the peripheral portion 22.

[0136] The grinding of the rings 70A, 70B before the assembly of the latter to the receiving sleeve DR allows the use of precision tools, making it possible, in an exemplary embodiment, to achieve a tolerance of less than approximately ±0.005 mm with regard to the geometry of the internal surface 74 of the rings, and therefore of the internal surface 22A of the peripheral part.

[0137] The coating applied in the optional step A2c makes it possible to harden the internal surface 74 of each ring, to prevent erosion of this surface during operation and to protect this surface in the event of involuntary contact between the central 20 and peripheral 22 parts.

[0138] The application of this coating in step A2c is for example carried out, for each ring, by means of a nozzle oriented at 45 degrees relative to the axis of the ring, from each side of the ring, so as to obtain a deposition of the coating over the entire internal surface 74 of each ring.

[0139] Instead of step A2 or in addition to it, step A may comprise a step A3 consisting of: • A3a) provide the DT transfer sleeve and the 90 hoop; then • A3b) mount the hoop 90 around the transfer sleeve DT so that the hoop interface surface 92A surrounds the sleeve interface surface 54, being in close contact with the latter.

[0140] Step A3a comprises, for example, on the one hand, drilling the fluid passages 64 (or, more generally, at least part of the transfer fluid paths TFP1A to TFP1C) radially through the transfer sleeve DT from the outside thereof, by placing a drilling tool 127 opposite the sleeve interface surface 54 ([Fig. 10C]), and, on the other hand, drilling the fluid conduits 94A-94C within the hoop 90, comprising drilling the first ends 96A-96C of the conduits, as well as, where appropriate, the radial portions 104A-104C of the conduits, by means of a drilling tool 128 placed inside the hoop 90, and drilling the second ends 102A-102C of the conduits ([Fig. 10D]), as well as, where appropriate, the radial portions 104A-104C of the conduits ([Fig. 10D]). where appropriate, axial portions 106A-106C of the conduits, by means of a drilling tool 129 placed facing the corresponding axial end of the hoop 90 ([Fig.10D]).

[0141] Step A3b comprises for example bringing the hoop into abutment against the radial annular flange 62 of the sleeve 50, on the second axial side, then screwing the nut 108 onto the threaded external surface 60 of the sleeve 50 against the axial end 90A of the hoop, on the first axial side.

[0142] In cases where steps A2 and A3 are both implemented, the assembly of the rings 70A, 70B on the sleeve 50 and the assembly of the hoop 90 on the sleeve 50 can be carried out in any order.

[0143] Step B comprises the interposition of the two bearings 110A, 110B between the central part 20 and the peripheral part 22, on either side of the annular space 23.

[0144] More precisely, step B comprises for example successively: • Bl) mounting a first of the bearings 110B around the external surface 20A of the central part 20, so that the internal ring 114B thereof is axially in abutment, on the first axial side SI, against the shoulder 35B of the central part; • B2) the installation of the peripheral part 22 around the central part 20, so that the shoulder 52E of the sleeve 50 is axially in abutment, on the first axial side SI, against the outer ring 116B of the first bearing 110B; • B3) the assembly of the second bearing 110A around the journal 34 of the part central, so that the outer ring 116A of this second bearing is axially in abutment against the shoulder 52D of the sleeve 50, in the direction of the first axial side S1; • B4) mounting the nut 122 on the pivot 34 of the central part for axially prestress the assembly formed, on the one hand, by the two bearings 110A, 110B, and, on the other hand, by the sleeve 50 and the rings 70A, 70B or, more generally, by the peripheral part 22.

[0145] Before step B4, the method advantageously comprises determining the appropriate dimensions for the shim 124, then machining it to said dimensions, and finally interposing the shim 124 between the inner ring 114A of the other bearing 110A and the shoulder 35A of the central part 20. VI. Implementation process

[0146] A method of implementing a device of the type described above generally comprises: • the selective supply of fluid to the first fluid paths FP1A-FP1C, via the fluid inlets 14A-14C of the device; • the circulation of the fluid in the first fluid paths FP1A-FP1C up to the transfer chambers 24A-24C; • the circulation of the fluid in the second fluid paths FP2A-FP2C from the transfer chambers 24A-24C, to the fluid outlets 16A-16C of the device; and • the rupture of the support webs 115 under the effect of a torque along the axis 8 applied to the annular row of support webs 115 by one of the central 20 and peripheral 22 parts, in this case the peripheral part 22, in the event of seizure of the bearing.

[0147] In normal operation, the circulation of the fluid in the first fluid paths FP1A-FP1C comprises the circulation of the fluid in the fluid channels 36A-36C and, from the latter, in the fluid tappings 38A-38C.

[0148] The circulation of the fluid in the second fluid paths FP2A-FP2C comprises the circulation of the fluid in the fluid passages 76A, 76B of the rings 70A, 70B, in the fluid passages 64 of the sleeve 50, and in the fluid conduits 94A, 94B, 94C of the hoop 90.

[0149] The method further comprises circulating a leakage flow of the fluid, from at least one of the transfer chambers 24A-24C, into the enclosure 112A, 112B of each bearing 110A, 110B, passing through the corresponding second annular region 26A, 26D, and lubricating the bearing by means of the leakage flow of the fluid.

[0150] [Fig. 11] illustrates for example the device 10 in a phase where only the fluid inlet 14A is supplied with fluid 130, the latter therefore circulating in the first channel 36A then in the first series 38A of fluid tappings, then, passing through the transfer chamber 24A, the fluid continues its circulation through the fluid passages 76A of the ring 70A, the passages 64A of the sleeve 50, and the conduits 94A of the hoop 90, until it leaves the device through the fluid outlet 16A. A minor portion 132 of the fluid leaks from the transfer chamber 24A by circulating in the annular space 23 in the direction of the two axial sides C1 and C2 until it reaches the enclosure 112A, 112B of each bearing 110A, 110B and lubricates each bearing. VII. Turbomachine

[0151] [Fig. 12] illustrates a turbomachine 210, for example a twin-spool, dual-flow turbojet engine for aircraft, generally comprising a fan 212 intended for the suction of an air flow F1 dividing downstream of the fan into a primary flow F2 circulating in a primary flow channel, hereinafter referred to as the primary vein PV, and a secondary flow F3 circulating in a secondary flow channel, hereinafter referred to as the secondary vein SV, arranged around the primary vein PV.

[0152] The turbomachine generally comprises a low pressure compressor 214, a high pressure compressor 216, a combustion chamber 218, a high pressure turbine 220 and a low pressure turbine 222 which jointly define the primary stream PV.

[0153] The respective rotors of the high pressure compressor and the high pressure turbine are connected by a shaft called a "high pressure shaft", while the respective rotors of the low pressure compressor and the low pressure turbine are connected by a shaft called a "low pressure shaft", in a well-known manner. These rotors are rotatably mounted around an axis 228 of the turbomachine.

[0154] The turbomachine comprises a device 10 of the type described above, with axis 8 for example merged with axis 228 of the turbomachine 210.

[0155] A stator of the turbomachine is integral with one of the central 20 and peripheral 22 parts of the device, in this case the central part 20. A rotor of the turbomachine is integral with the other part, in this case the peripheral part 22, of the device.

[0156] The device 10, illustrated very schematically in [Fig. 12], is for example arranged so that its fluid outlets 16A-16C are connected to fluid chambers of actuators carried by the aforementioned rotor to allow the latter to be controlled. In particular, the device is for example of the type commonly called OTB (“Oil Transfer Bearing”) and intended to supply a cylinder controlling the pitch of blades of one or more propellers as well as an actuator for securing the blades.

Claims

Claims

1. Device comprising a central portion (20) and a peripheral portion (22) and at least one bearing (110A, 110B) for guiding the central and peripheral portions in rotation relative to each other along an axis (8), the bearing comprising an inner ring (114A, 114B) and an outer ring (116A, 116B), a first of said rings being rigidly connected to a first portion among said central and peripheral portions, characterized in that the bearing (110A, 110B) comprises, for rigidly connecting the second of said rings to the second portion among said central and peripheral portions, an annular row of support webs (115) extending longitudinally while being distributed around the axis (8) and circumferentially spaced from each other,the support sails having respective first radial ends (115 A) rigidly connected to the second ring and respective second radial ends (115B) rigidly connected to the second part.,

2. Device according to claim 1, in which the support sails (115) extend along planes containing the axis (8).

3. Device according to claim 1 or 2, in which the support webs (115) are made of a material in which at least one of the second part and the second ring is made.

4. A device according to any one of claims 1 to 3, wherein the second ring is the outer ring (116A) of the bearing.

5. Device according to any one of claims 1 to 4, comprising an annular row of rolling elements (118) interposed between the inner ring (114A) and the outer ring (116A).

6. Device according to any one of claims 1 to 5, in which: • the central part (20) has an external surface (20A) with a geometry of revolution along the axis (8); • the peripheral part (22) has an internal surface (22A) with a geometry of revolution along the axis (8) arranged around the external surface (20A) of the central part with the ability to rotate relative to the latter along the axis (8); • transfer chambers (24A to 24C) are defined between the external surface (20A) of the central part and the internal surface (22A) of the peripheral part; • the central part (20) defines first fluidic paths (FP1A to FP1C) respectively connecting fluid inlets (14A to 14C) of the device to the transfer chambers (24A to 24C) through said external surface (20A); • the peripheral part (22) defines second fluid paths (FP2A to FP2C) respectively connecting fluid outlets (16A to 16C) of the device to the transfer chambers (24A to 24C) through said internal surface (22A); whereby the device is configured for the transfer of several fluid paths between the fluid inlets (14A to 14C) and the fluid outlets (16A to 16C).

7. Turbomachine (210) for aircraft, comprising at least one device according to any one of claims 1 to 6, and comprising a stator secured to one of the central (20) and peripheral (22) parts of the device and a rotor secured to the other central (20) or peripheral (22) part of the device.

8. Method for implementing a device (10) according to any one of claims 1 to 5, comprising breaking the support webs (115) under the effect of a torque along the axis (8) applied by one of the central (20) and peripheral (22) parts to the annular row of support webs (115) in the event of seizure of the bearing.

9. Method for implementing a device (10) according to claim 6, comprising: • selectively supplying fluid to the first fluid paths (FP1A to FP1C), via the fluid inlets (14A to 14C) of the device; • circulating the fluid in the first fluid paths into the transfer chambers (24A to 24C); • circulating the fluid in the second fluid paths (FP2A to FP2C) from the transfer chambers (24A to 24C), to the fluid outlets (16A to 16C) of the device; and • breaking the support webs under the effect of a torque along the axis applied by one of the central (20) and peripheral (22) parts to the annular row of support webs (115) in the event of seizure of the bearing. 24

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