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 sails (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 a frangible support and limited size. 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 aircraft performance and, in this respect, contributing to the reduction of their environmental impact. 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 may be transmitted between the two concentric rings of the bearing and therefore between the two elements via the bearing, which in some cases may cause damage that 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 frame to a rotating reference frame, or more generally between two reference frames in relative rotation with respect to each other, such reference frames being in practice defined by parts or assemblies of parts.

[0006] In the field of turbomachinery for aircraft propulsion, the fixed reference frame of such a device can be defined by a stator of such a turbomachine, while the rotating reference frame can be defined by a rotor of the same turbomachine. In such applications, the fluid is, for example, oil or another fluid intended for the hydraulic control of actuators. In specific applications, such a device, of the type commonly referred to as an OTB (from the Anglo-Saxon terminology "Oil Transfer Bearing"), is intended to supply a cylinder controlling the pitch of one or more propeller blades, as well as a blade safety actuator.

[0007] Fluid film-damped bearings, one of whose rings is supported by a flexible, offset structure commonly called a "squirrel cage," are well known. Such a structure has the particular characteristic of breaking if a sufficiently high torque is applied to it.

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

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

[0010] The invention relates to a device comprising a bearing which limits the risk of damage in the event of the latter seizing, and whose mass and size 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 the peripheral part, whose bearing 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 about 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, for rigidly connecting the second of said rings to the second part among said central and peripheral parts, an annular row of support webs extending longitudinally, being distributed around the axis and circumferentially spaced 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 walls inherently offer good resistance to radial forces but limited resistance to circumferential forces, which translate, for each of the walls, into shear forces.

[0014] The support webs thus provide a rigid connection between the relevant bearing ring and the corresponding part of the device when the latter is operating normally, while allowing this rigid connection to break upon application of a sufficiently high torque, as occurs in a seizing situation. In this sense, the support webs define a flexible support for the relevant bearing ring.

[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 part has an external surface with geometry of revolution about an axis.

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

[0021] In preferred embodiments, transfer chambers are defined between the external surface of the central part and the internal surface of the peripheral part.

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

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

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

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

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

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

[0028] The invention will be better understood, and other details, advantages and features thereof will become apparent from the following description, given by way of non-limiting example and with reference to the accompanying 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 cross-sectional view of a device such as that of the [Fig.l], configured for the transfer of multiple fluid paths;

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

[0032] [Fig.4A] is a schematic axial cross-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 cross-sectional view of a peripheral part of the device of the [Fig.2];

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

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

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

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

[0039] [Fig.1OA] is a schematic axial cross-sectional view of the rings of the peripheral part, illustrating a step in the manufacturing process of the [Fig.9];

[0040] [Fig.1OB] is a view similar to [Fig.1OA], illustrating another step in the manufacturing process of [Fig.9];

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

[0042] [Fig.1OD] 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 cross-sectional view of a turbomachine comprising a device such as that of [Fig.1] or that of [Fig.2].

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

[0046] Figure 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 part 20 and peripheral part 22 in rotation relative to each other about an axis 8. In typical applications, one of the parts is fixed to a stator while that the other part is attached to a rotor, for example within a turbomachine, as will become clearer in what follows.

[0047] In the present description, the axial direction X is the direction of axis 8. The radial direction R is at every point a direction orthogonal to and passing through axis 8, and the orthoradial or circumferential direction C is at every point a direction orthogonal to the radial direction R and to axis 8. A transverse plane is a plane orthogonal to axis 8. Unless otherwise indicated, the terms "internal" and "external" refer respectively to a relative proximity and a relative distance of an element from 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 circumferentially spaced 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 made by pre-machining the second ring or outer ring 116A, or be welded to the latter by their first radial ends 115A.

[0052] The support webs 115 can be attached to the second part or peripheral part 22 by welding their second radial ends 115B to it. Alternatively, the second radial ends 115B of the support webs 115 can be rigidly connected to an intermediate ring, itself press-fitted into the second part or peripheral part 22, for example by shrink fitting. Alternatively still, the second ring or outer ring 116A, the support webs 115, and such an intermediate ring can be made as a single unit, for example by means of an additive manufacturing technique.

[0053] The support sails 115 allow a rigid connection between the second ring or outer 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 a person skilled in the art will understand, the support webs 115 thus exhibit a tendency to break when a torque is applied to them along the axis 8, typically resulting from a bearing seizure. In such a situation, the rupture of the support webs 115 prevents 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 amount of material, and can therefore imply a limited mass, in particular compared with the squirrel cages of known devices.

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

[0057] Furthermore, 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 differential thermal expansion between these elements. Alternatively, the support webs 115 can be made of the same material as the second ring or outer ring 116A, or of a different material from the materials constituting the second part and the second ring.

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

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

[0060] Figure 2 illustrates such a device 10, intended for transferring several fluid paths between two frames rotating relative to each other, for example between a turbomachine stator, defining a fixed frame, and a turbomachine rotor, defining a frame rotating about axis 8. In the example described, the number of fluid paths is of three, but the principles described below are of course applicable regardless of the number of fluid paths.

[0061] The stator includes, 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 includes 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 fluid flow from the fluid inlets to the fluid outlets through the device 10, a reverse direction of flow is possible without departing from the scope of the invention. In this respect, the terms "inlet" and "outlet" should be considered, throughout this application, as synonymous with passage orifices or "fluid ports."

[0062] Still with reference to [Fig.2], the device 10 generally comprises 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 the peripheral part 22 may be reversed, with the central part then being integral with a rotor and the peripheral part being integral with a stator.

[0064] The central portion 20 has an external surface 20A with a geometry of revolution about axis 8, and preferably cylindrical in shape. The peripheral portion 22 has an internal surface 22A with a geometry of revolution about axis 8, arranged around the external surface 20A of the central portion 20, and preferably with a shape broadly similar to that of the external surface 20A up to a homothetic transformation, the two surfaces possibly differing further by the presence of different annular orifices and grooves, as will become clearer below. The internal surface 22A of the peripheral portion 22 may be formed jointly by several parts 50, 70A, 70B, 90 belonging to the peripheral portion 22, as will become clearer below.

[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] In general, the annular space 23 comprises, arranged axially in alternation, 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 fluid leakage between the central part 20 and the peripheral part 22 from the transfer chambers 24A-24C.

[0067] For each of the fluid paths to be transferred, the central part 20 includes a fluidic path in fluidic communication with a corresponding fluidic path within the peripheral part 22, in order to allow circulation of the fluid of the path considered from a corresponding fluidic inlet 14A-14C attached to the central part (figures 2 and 3), to a corresponding fluidic outlet 16A-16C attached to the peripheral part (figures 2 and 5). Furthermore, the two-to-two communication between the fluidic paths of the central part 20, referred to as first fluidic paths hereafter and referenced FP1A-FP1C ([Fig.4A]), and the fluidic paths of the peripheral part 22, referred to as second fluidic paths hereafter 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 become clearer in what follows. Each first fluidic path FP1A-FP1C therefore connects a corresponding fluidic inlet 14A-14C to a corresponding transfer chamber 24A-24C, while each corresponding second fluidic path FP2A-FP2C connects the corresponding transfer chamber 24A-24C to the corresponding fluidic outlet 16A-16C.

[0068] The fluidic inlets 14A-14C are preferably arranged at a longitudinal end of the device located on a first axial side SI, while the fluidic outlets 16A-16C are preferably arranged at a longitudinal end of the device located on a second, opposite axial side S2. In other embodiments, the fluidic inlets and outlets may 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 of this located on the first axial side S1, a connecting portion 32, and at another end of this located on the second axial side S2, a trunnion 34. The trunnion 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 fluidic paths FP1A-FP1C, the main portion 30 generally comprises corresponding fluidic channels 36A-36C, respectively connected, on the first axial side SI, to the fluidic inlets 14A-14C, and for each of the fluidic channels 36A-36C, at least one fluidic branch 38A-38C connected to the fluidic channel 36A-36C considered, on the second axial side S2, and opening through the external surface 20A.

[0071] The fluidic channels 36A-36C are concentric channels extending along the axis 8. The aforementioned external surface 20A surrounds all of these fluidic 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 with respect 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 trunnion side 34, i.e., the second axial side, the channels 36A-36C have ends 39A-39C staggered along the axis 8 ([Fig. 4A]) such 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 channel that extends furthest towards the trunnion 34, while the third channel 36C is the channel that extends the least towards the trunnion 34.

[0074] In the preferred example illustrated, the main portion 30 comprises, for each fluidic channel 36A-36C, a corresponding series of fluidic branches 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 fluidic branches of each series 38A-38C thus originate from the corresponding channel 36A-36C.

[0075] To this end, 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 trunnion 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 trunnion 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 spigots 38A-38C of each series are for example arranged in the form of an annular row of spigots regularly distributed around the axis 8. The spigots 38A-38C preferably extend each in the radial direction R.

[0077] The connection portion 32 comprises fluidic 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 fluidic inlets 14A-14C of the device and intended to be connected to corresponding connection means on the fluid supply board 12 ([Fig.2]). More specifically, each second end forms, for example, a connection plug adapted to be connected to a corresponding plug on the fluid supply board 12.

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

[0079] Furthermore, the concentricity of the fluidic channels 36A-36C limits deformations of the central portion 20 due to fluid pressure in the first fluidic paths FP1A-FP1C during operation. The central portion 20 can therefore have a lighter design without compromising the overall operation of the device 10.

[0080] Alternatively, the first fluidic paths FP1A-FP1C can be constituted in a different way than 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 fret 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 these, an intermediate portion 52C also of annular shape, with a cross-section smaller than that of the end portions 52A, 52B. The internal surface which delimits the bore 52 thus has two shoulders 52D, 52E which axially delimit the intermediate portion 52C between them.

[0084] The sleeve 50 further comprises an annular rib 56 formed in radial projection inwards 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 geometry of revolution, for example cylindrical, which helps to delimit the intermediate portion 52C of the bore between the first and second parts 52C1, 52C2.

[0085] The sleeve 50 has an external threaded 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 fluidic paths FP2A-FP2C, the sleeve 50 comprises at least one corresponding fluidic passage 64 for each second fluidic path, and preferably a corresponding series of such fluidic passages 64 for each second fluidic path. These fluidic passages 64 each have an internal end opening through the internal surface of the sleeve 50 into the intermediate portion 52C of the bore, and an external end opening through the external surface 54 of the sleeve.

[0087] In the illustrated example which concerns a three-way fluidic device, the aforementioned fluidic passages are distributed 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 fluidic passages of the second series 64B open into the transfer chamber 24B ([Fig.2]). mB Rings

[0089] The rings 70A, 70B (visible on [Fig.2] and, in more detail, on figures 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 this description, form corresponding parts of the internal surface 22A of the peripheral part.

[0091] In the illustrated example, the rings 70A, 70B have respective flanks 75B, 75C (figures 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 intercalated between the internal surfaces 74 of the rings, jointly defines 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 part 22 generally facilitates the grinding operations of the internal surface 22A and / or the application of a protective coating to it, by dividing the latter into several sections that can be treated independently of each other. Each ring 70A, 70B has a smaller axial extent compared to the total axial extent of the internal surface 22A, so that certain grinding tools and certain tools for spraying protective coatings, which would be unsuitable for treating the internal surface 22A in its entirety due to the latter's axial extent, can instead be used to treat the internal surface 74 of each ring 70A, 70B taken individually, as well as, in the illustrated example, the internal end surface 58 of the annular rib 56. In the absence of the rings, access to the latter is also facilitated by the larger internal diameter of the first and second parts 52C1, 52C2 of the intermediate portion 52C of the bore 52, compared to the internal diameter of the internal surface 22A.

[0093] This makes it possible to obtain a particularly small gap between surfaces 20A and 22A. As a result, a satisfactory seal can be achieved between the central part 20 and the peripheral part 22, even when the overlap length, i.e., the axial extent of the annular space 23 defined between these parts, is relatively small compared to what is required in devices not using such rings. Furthermore, reducing the overlap length required to achieve a satisfactory seal offers the particular advantage of reduced mass and size for the device 10.

[0094] To help define some of the secondary fluid paths FP2A-FP2C, each ring 70A, 70B has fluid passages 76A, 76B, each having an internal end 78 opening, through the internal surface 74 of the ring, into a corresponding transfer chamber 24A, 24C. The internal 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 designed to extend a short distance from the external surface 20A of the central portion 20 and thus limit axial fluid leakage 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 (Figures 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 complementaryly, the transfer chambers 24A-24C can 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 7OA, 70B.

[0097] A compressible annular sealing gasket 82 protrudes from a groove formed in the aforementioned flank 75B, 75C of each of the rings 70A, 70B, towards the annular rib 56, so as to bear against the flanks 56A, 56B of the latter and thus prevent fluid leakage between each ring 70A, 70B and the rib 56. Alternatively or in addition, grooves for the gaskets 82 may respectively be 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 that delimits the bore 52, such that the aforementioned passages open into these distribution cavities 86A, 86B. Alternatively or complementaryly, 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 leakage out of the intermediate portion 52C of the bore.

[0101] Each of the annular sealing gaskets 88A, 88B, for example, projects 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. Alternatively or in addition, such a groove may be formed, for each gasket 88A, 88B, in the internal surface of the sleeve 50.

[0102] In order to minimize the mass of the device, the opposing sides 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 flanges, each extending in projection towards the first axial side and towards the second side axial, respectively from each of the radial ends of the middle portion of the ring under consideration.

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

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

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

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

[0107] The fret 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 referred to as the fret interface surface in what follows.

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

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

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

[0111] To allow fluid circulation between the fluid passages 64 of the sleeve 50 and the fluid conduits 94A-94C of the ferrule 90, annular distribution cavities 98A-98C are provided in the form of grooves formed in the external surface 54 of the sleeve so that the external 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 (Figures 5 and 6). Alternatively or additionally, grooves can be formed in the internal surface 92A of the sleeve to define the distribution cavities 98A-98C.

[0112] The sealing of the distribution cavities 98A-98C is ensured, for example, by means of compressible annular sealing gaskets 100 interposed between the external surface 54 of the sleeve and the internal surface 92A of the collar, axially on either side of each of the distribution cavities 98A-98C. To best limit the risk of damage to the gaskets 100 during assembly and disassembly operations of the device, the external surface 54 of the sleeve and the internal surface 92A of the collar 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 to the first axial side SI.

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

[0114] Furthermore, each fluidic conduit 94A, 94B, 94C has a second end 102A-102C, opposite the first end 96A-96C, arranged at an axial end of the ferrule 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 fluidic outlets 16A-16C of the device 10.

[0115] Each of the fluidic conduits 94A-94C has, for example, an angled 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 with the second end 102A-102C of the conduit. The radial portions 104A-104C of the different pairs of conduits are staggered axially, like the series 64A-64C of fluidic passages of the sleeve 50. The axial portions 106A-106C of the conduits are for example defined within corresponding ribs 107A-107C, formed in radial projection outwards from an external surface 92B of the fret, and extending longitudinally.

[0116] Furthermore, the fret 90 is rigidly linked 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 external threaded surface 60 of the sleeve 50 against an axial end 90A of the fret, on the first axial side SI (figures 5 and 6).

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

[0118] Splitting the peripheral part 22 into the transfer sleeve DT and the collar 90 makes it easier to drill the fluidic transfer paths, in this case the drilling of the fluidic passages 64 of the sleeve 50. Indeed, 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 opposite the interface surface of sleeve 54, without it being necessary to then plug the radially external end of these fluidic transfer paths (or passages 64) since this external end is intended to be connected to the conduits 94A-94C of the collar 90.These conduits can be easily made, including their first ends 96A-96C and, where appropriate, their radial portions 104A-104C, because the inner diameter of the fret is larger than that of the bore 52, making it possible to pass a radial drilling tool from inside the fret 90.

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

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

[0121] IV. Connection between central and peripheral parts

[0122] With reference to figures 2 and 5, the central part 20 and peripheral part 22 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 outer 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] Furthermore, each of the bearings 110A, 110B is advantageously housed in a respective enclosure 112A, 112B in fluidic communication with a second annular region 26A, 26D corresponding among the aforementioned second annular regions of annular space 23.

[0125] Such an arrangement allows each bearing to be lubricated by means of fluid leaks from the transfer chambers 24A-24C and passing through the corresponding second annular region 26A, 26D, into the housing 112A, 112B of the bearing. The flow rate of such leaks is determined in particular by the cross-sectional area of ​​the second annular regions 26A-26D.

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

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

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

[0129] The bearings 110A, 110B are advantageously of the angular 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 butted, on the first axial side SI, against the shoulder 35B which is formed at one end of the external 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 butted, 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 trunnion 34 of the central part 20 and its outer ring 116A is axially abutted, in the direction of the first axial side SI, against the shoulder 52D of the sleeve 50. In addition, a nut 122 is screwed onto the trunnion 34 of the central part 20 so as to be axially abutted, in the direction of the first axial side SI, 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 external 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 components of the latter in the axial direction and to guarantee a determined axial preload of the bearings 11 OA, 110B.

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

[0133] With reference to [Fig. 9], a manufacturing process for device 10 of [Fig. 2] generally comprises the steps of: • A) make available the central part 20 and the peripheral part 22; then • B) mount the peripheral part 22 around the central part 20 so as to allow a relative rotation between these two parts and to connect the first fluidic paths and the second fluidic paths in pairs.

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

[0135] Step A may include a step A2 consisting of: • A2a) make available the DR receiving socket and the 70A, 70B rings; • A2b) rectify 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 using a rectifying tool 125 ([Fig.1OA]); then • A2c) Optionally, apply a protective coating to the inner surface 74 of each of the rings 70A, 70B by spraying using a spray tool 126 ([Fig.1OB]) for example configured to spray a fluid intended to form the coating at an angle of approximately 45 degrees onto the inner surface 74; then • A2d) mount the rings 70A, 70B in the bore 52 tightly so that the internal surface 74 of each of the rings 70A, 70B contributes to forming the internal surface 22A of the peripheral part 22.

[0136] Grinding the rings 70A, 70B before assembling them to the receiving sleeve DR allows the use of precision tools, making it possible, in one embodiment, to achieve a tolerance of less than approximately ±0.005 mm with regard to concerns 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 in operation and to protect this surface in case of unintentional contact between the central part 20 and peripheral part 22.

[0138] The application of this coating in step A2c is for example implemented, for each ring, by means of a nozzle oriented at 45 degrees with respect to the axis of the ring, from each side of the ring, so as to obtain a deposit of the coating on the entire internal surface 74 of each ring.

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

[0140] Step A3a includes, for example, on the one hand, drilling the fluid passages 64 (or, more generally, at least a portion of the fluid transfer paths TFP1A to TFP1C) radially through the transfer sleeve DT from outside the sleeve, by placing a drilling tool 127 opposite the sleeve interface surface 54 ([Fig. 10 ... axial portions 106A-106C of the conduits, by means of a drilling tool 129 placed opposite the corresponding axial end of the fret 90 ([Fig.lOD]).

[0141] Step A3b includes for example bringing the fret against the radial annular flange 62 of the sleeve 50, on the second axial side, then screwing the nut 108 onto the external threaded surface 60 of the sleeve 50 against the axial end 90A of the fret, 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 fret 90 on the sleeve 50 can be carried out in any order.

[0143] Step B includes 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 specifically, step B includes, for example, successively: • Bl) the mounting of a first of the bearings 110B around the external surface 20A of the central part 20, so that the internal ring 114B of it is axially in butt, 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 butt, on the first axial side SI, against the outer ring 116B of the first bearing 110B; • B3) the mounting of the second bearing 110A around the trunnion 34 of the part central, so that the outer ring 116A of this second bearing is axially against the shoulder 52D of the sleeve 50, in the direction of the first axial side S1; • B4) the mounting of the nut 122 on the trunnion 34 of the central part to axially pre-stress 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 process advantageously includes 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 Procedure

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

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

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

[0149] The method further includes 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] Figure 11 illustrates, for example, the device 10 in a phase where only the fluidic inlet 14A is supplied with fluid 130. The fluid thus circulates in the first channel 36A and then in the first series 38A of fluidic outlets. Passing through the transfer chamber 24A, the fluid continues its circulation through the fluidic passages 76A of the ring 70A, the passages 64A of the sleeve 50, and the conduits 94A of the ferrule 90, until it exits the device through the fluidic outlet 16A. A minor portion 132 of the fluid leaks from the transfer chamber 24A, circulating in the annular space 23 towards 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 turbofan engine for aircraft, generally comprising a fan 212 for the intake of an airflow Fl which divides downstream of the fan into a primary flow F2 flowing in a primary flow channel, hereinafter referred to as the primary flow PV, and a secondary flow F3 flowing in a secondary flow channel, hereinafter referred to as the secondary flow SV, arranged around the primary flow 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 together define the primary PV stream.

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

[0154] The turbomachine includes a device 10 of the type described above, with an axis 8 for example coinciding with the 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 schematically in [Fig. 12], is arranged, for example, so that its fluidic outlets 16A-16C are connected to fluidic chambers of actuators mounted on the aforementioned rotor to enable the control of these actuators. In particular, the device is, for example, of the type commonly known as an OTB (Oil Transfer Bearing) and is intended to supply a cylinder controlling the pitch of one or more propeller blades, as well as a blade safety actuator.

Claims

1.

2.

3.

4.

5.

6. Demands A device comprising a central part (20) and a peripheral part (22) and at least one bearing (110A, 110B) for guiding the central and peripheral parts in rotation relative to each other about 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 part among said central and peripheral parts, characterized in that the bearing (110A, 110B) comprises, for rigidly connecting the second of said rings to the second part among said central and peripheral parts, an annular row of support webs (115) extending longitudinally, distributed around the axis (8) and circumferentially spaced from each other, the support webs having respective first radial ends (115A) rigidly connected to the second ring and second radial ends (115B) respectively rigidly connected to the second part,the support webs being dimensioned to break under the effect of shear forces resulting from a couple 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 bearing seizure, the support webs thus constituting a frangible support for the second ring. Device according to claim 1, wherein the support sails (115) extend along planes containing the axis (8). Device according to claim 1 or 2, wherein the support sails (115) are made of a material in which at least one of the second part and the second ring is made. A device according to any one of claims 1 to 3, wherein the second ring is the outer ring (116A) of the bearing. A 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). A device according to any one of claims 1 to 5, wherein: • the central part (20) has an external surface (20A) with a geometry of revolution about the axis (8); • The peripheral part (22) has an internal surface (22A) with a geometry of revolution about the axis (8) arranged around the external surface (20A) of the central part, with the ability to rotate relative to the latter about 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) connecting fluidic 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 fluidic paths (FP2A to FP2C) connecting fluidic 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 multiple fluid paths between the fluidic inlets (14A to 14C) and the fluidic outlets (16A to 16C).

7. Aircraft turbomachine (210), comprising at least one device according to any one of claims 1 to 6, and comprising a stator integral with one of the central (20) and peripheral (22) parts of the device and a rotor integral with the other central (20) or peripheral (22) part of the device.

8. Method of 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 about 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 bearing seizure.

9. Method of implementing a device (10) according to claim 6, comprising: • selectively supplying fluid to the first fluidic paths (FP1A to FP1C), by the fluidic inlets (14A to 14C) of the device; the circulation of the fluid in the first fluidic paths up to the transfer chambers (24A to 24C); the circulation of the fluid in the second fluidic paths (FP2A to FP2C) from the transfer chambers (24A to 24C), to the fluidic outlets (16A to 16C) of the device; and the breakage of the support sails 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 sails (115) in case of bearing seizure.

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