Multi-way fluid transfer device comprising fluid transfer rings providing dynamic sealing

Abstract

The invention relates to a device (10) for transferring a plurality of fluid paths, the device comprising: a central portion (20); a peripheral portion (22) rotating about the central portion; and transfer chambers (24A-24C) between the central and peripheral portions. The central portion defines first fluid paths (FP1A-FP1C) connecting fluid inlets (14A, 14C) to the transfer chambers. The peripheral portion (22) defines second fluid paths (FP2A-FP2C) connecting fluid outlets (16A-16C) to the transfer chambers. The peripheral portion comprises a bushing (50) and at least two transfer rings (70A, 70B) floatingly radially mounted in the bushing (50) and each defining, together with the latter, at least some of the second fluid paths (FP2A-FP2C). The peripheral portion (22) comprises return means for axially urging each transfer ring (70A, 70B) against a corresponding shoulder (118A, 118B).

Description

[0001] Description

[0002] Title: Multi-way fluid transfer device comprising fluid transfer rings ensuring dynamic sealing

[0003] technical field

[0004] The present invention relates to the field of fluid transfer devices designed to transfer multiple fluid paths from a fixed frame of reference to a rotating frame of reference, or more generally between two frames of reference rotating relative to each other. Such frames of reference are in practice defined by parts or assemblies of parts.

[0005] In specific applications within the field of turbomachinery for aircraft propulsion, the fixed reference frame can be defined by a stator of such a turbomachine, while the rotating reference frame can be defined by its rotor. In such applications, the fluid is, for example, oil or another fluid intended for the hydraulic control of actuators. In specific applications, the device under consideration is of the type commonly referred to as an OTB (Oil Transfer Bearing), and is thus designed to supply a cylinder controlling the pitch of one or more propeller blades, as well as a blade safety actuator.

[0006] Prior art

[0007] Multi-channel fluid transfer devices between two relatively rotating reference frames, such as those used to control actuators in turbomachinery for aircraft propulsion, are generally bulky and heavy, which penalizes the overall performance of turbomachinery and results in a negative impact on climate change.

[0008] There is therefore a need for an improved multi-way fluid transfer device. 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.

[0009] Description of the invention

[0010] The invention proposes a device for transferring fluid through multiple channels, comprising:

[0011] - a central part having an external surface with a geometry of revolution about an axis; a peripheral part arranged around the external surface of the central part with the ability to rotate relative to the latter about the axis;

[0012] - an internal annular space defined between the external surface of the central part and the peripheral part, and transfer chambers defined as annular portions of the internal annular space; in which:

[0013] - the central part defines the first fluidic paths connecting respectively the fluidic inlets of the device to the transfer chambers through said external surface;

[0014] - the peripheral part defines secondary fluidic paths connecting respectively fluidic outputs of the device to the transfer chambers;

[0015] - the peripheral part includes a socket having an internal annular socket surface and comprising fluidic socket paths, each constituting a part of one of the corresponding second fluidic paths;

[0016] - the peripheral part comprises two structures forming respectively two shoulders projecting radially inwards from the internal annular surface of the socket;

[0017] - the peripheral part comprises two transfer rings respectively mounted radially floating between said external surface of the central part and the internal annular surface of the bushing so that each of the transfer rings externally delimits a corresponding part of the internal annular space including one of the corresponding transfer chambers;

[0018] - when each transfer ring is in a nominal position centered along the axis, an external radial clearance defined between each transfer ring and the internal annular surface of the bushing is greater than an internal radial clearance, defined between each transfer ring and the external surface of the central part and forming said corresponding part of the internal annular space;

[0019] - the peripheral part includes return means to axially stress each transfer ring against one of the two corresponding shoulders; each transfer ring includes at least one fluidic ring passage forming part of one of the corresponding second fluidic paths and communicating with one of the corresponding bushing fluidic paths.

[0020] The two transfer rings allow for both:

[0021] - to fluidly connect at least some of the first fluidic paths (defined within the central part) to corresponding socket fluidic paths (defined within the socket); and

[0022] - to achieve dynamic sealing around the external surface of the central part, at the axial ends of the internal annular space, in the manner of hydrodynamic bearings.

[0023] In general, the dynamic sealing provided by the transfer rings makes it possible to control fluid leaks through the axial ends of the internal annular space.

[0024] In preferred embodiments of the invention, these fluid leaks are used to lubricate bearings and are preferably limited to the flow rate necessary for this function.

[0025] In preferred embodiments of the invention, the internal annular surface of the bushing is provided with an annular rib arranged axially between the two transfer rings and spaced apart from them. In preferred embodiments of the invention, one of the bushing fluid paths, other than those communicating with the ring fluid passages, opens through an internal end surface of the rib.

[0026] In preferred embodiments of the invention, the return means comprise axially interposed compression springs between each transfer ring and the rib.

[0027] In preferred embodiments of the invention, the peripheral part includes angular indexing means for angularly indexing each transfer ring relative to the bushing.

[0028] In preferred embodiments of the invention, the angular indexing means comprise, for each transfer ring, at least one axial lug rigidly attached to one of the transfer ring considered and the rib, axially engaged with transverse clearance in a corresponding groove formed in the other of the transfer ring considered and the rib.

[0029] In preferred embodiments of the invention, the angular indexing means are configured to maintain angular coincidence between the ring fluidic passages and the corresponding bushing fluidic paths.

[0030] In preferred embodiments of the invention, two bearings, radially interposed between the central part and the sleeve axially on either side of the internal annular space to guide said central and peripheral parts in rotation relative to each other, comprise respective outer bearing rings mounted rigidly in the sleeve and constituting said structures forming said shoulders respectively.

[0031] The invention also relates to an aircraft turbomachine, comprising at least one device of the type defined above, 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.

[0032] The invention also relates to a method of implementing a device of the type defined above, comprising: - the selective supply of fluid to the first fluidic paths, by the fluidic inlets of the device;

[0033] - the circulation of the fluid in the first fluidic paths up to the transfer chambers;

[0034] - the circulation of the fluid in the second fluidic paths from the transfer chambers, up to the fluidic outlets of the device;

[0035] - the airtight closure of an external annular space, defined between each of the transfer rings and the internal annular surface of the sleeve, by a static contact between the transfer ring considered and the corresponding shoulder ensured by the return means;

[0036] - for each of the transfer rings, the establishment of a dynamic seal between the transfer ring in question and the external surface of the central part during the circulation of the fluid through the corresponding transfer chamber.

[0037] In preferred embodiments of the invention, the angular indexing means establish linear contacts between each transfer ring and the bushing.

[0038] In preferred embodiments of the invention, the method includes lubricating each of the bearings by an axial leakage of the fluid through said dynamic seal, from the corresponding transfer chamber.

[0039] The invention also relates to a method for manufacturing a device of the type defined above, comprising at least steps consisting of:

[0040] - A) make available the central part and the peripheral part; then

[0041] - B) mount the peripheral part around the central part so as to allow a relative rotation between these two parts and to connect the first fluidic paths and the second fluidic paths two-by-two.

[0042] In preferred embodiments of the invention, step B includes implementing a tight fit of the transfer rings around the external surface of the central part, the method comprising a subsequent step C consisting of rotating the central part and the peripheral part relative to create the internal radial clearance by lapping each transfer ring and the external surface of the central part.

[0043] Brief description of the drawings

[0044] 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:

[0045] [Fig. 1] is a schematic axial cross-sectional view of a device for transferring multiple fluid paths, according to a preferred embodiment of the invention;

[0046] [Fig. 2] is a view similar to figure 1, but in which transfer rings belonging to the device have been omitted;

[0047] [Fig. 3] is a schematic cross-sectional view of the device along the lll-lll plane of figure 1;

[0048] [Fig. 4A] is a schematic perspective view of a transfer ring and associated return means and angular indexing means, in a disassembled state;

[0049] [Fig. 4B] is a schematic perspective view of the transfer ring and associated return means and angular indexing means, in an assembled state;

[0050] [Fig. 5] is a schematic axial cross-sectional view of the transfer ring and associated return and angular indexing means, in the assembled state;

[0051] [Fig. 6] is a view similar to figure 4B, illustrating a variant of the invention;

[0052] [Fig. 7] is a view similar to figure 1, illustrating the same variant as figure 6;

[0053] [Fig. 8] is a schematic cross-sectional view of the device along plane VIII-VII I of figure 7;

[0054] [Fig. 9] is a schematic axial cross-sectional view of a turbomachine comprising a device for transferring several fluid paths according to the invention.

[0055] Throughout these figures, identical references may designate identical or analogous elements. Detailed exposition of preferred embodiments

[0056] I. General Information

[0057] Figure 1 illustrates a device 10 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 an 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.

[0058] In this 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.

[0059] The stator includes, for example, a fluid supply structure (not shown) having several fluid outlets, in this case three, intended to be connected respectively to fluid inlets 14A-14C of the device 10, while the rotor includes fluid receiving means (not shown) intended to be connected to fluid outlets 16A-16C of the device. Although this 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."

[0060] Referring to Figure 1, the device 10 generally comprises a central part 20 and a peripheral part 22 arranged around the central part 20, with the ability to rotate about the latter along axis 8. The central part 20 is, for example, intended to be fixed to the stator, which in this case is fixed to the aforementioned fluid supply structure, while the peripheral part 22 is, for example, intended to be fixed to 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 fixed to a rotor and the peripheral part being fixed to a stator.

[0061] The central part 20 has an external surface 20A with a geometry of revolution about axis 8, and preferably cylindrical in shape. The peripheral part 22 has an internal surface 22A with a geometry of revolution about axis 8, arranged around the external surface 20A of the central part 20. As will become clearer below, the internal surface 22A of the peripheral part 22 is formed jointly by several pieces belonging to the peripheral part 22 and, for this reason, exhibits discontinuities.

[0062] An annular space, hereinafter referred to as the internal annular space 23, is defined between the external surface 20A of the central part 20 and the internal surface 22A of the peripheral part 22.

[0063] For the purposes of this description, certain annular portions of the internal annular space 23 are designated as transfer chambers 24A-24C.

[0064] For each of the fluid paths to be transferred, the central part 20 comprises a fluidic path in fluidic communication with a corresponding fluidic path within the peripheral part 22, in order to allow the fluid of the path in question to flow from a corresponding fluidic inlet 14A-14C attached to the central part, to a corresponding fluidic outlet 16A-16C attached to the peripheral part. Furthermore, the pairwise communication between the fluidic paths of the central part 20, referred to as the first fluidic paths hereafter and referenced FP1A-FP1C, and the fluidic paths of the peripheral part 22, referred to as the second fluidic paths hereafter and referenced FP2A-FP2C, is implemented via the transfer chambers 24A-24C, defined between the external surface 20A of the central part 20 and the internal surface 22A of the peripheral part 22.Each first fluidic path FP1A-FP1C therefore connects a corresponding fluidic input 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 output 16A-16C.

[0065] The fluidic inlets 14A-14C are defined by a longitudinal end portion, hereinafter referred to as the connecting portion 32, of the central portion 20 located on a first axial side SI. The fluidic outlets 16A-16C can be arranged at a longitudinal end of the peripheral portion 22 located on a second axial side S2 opposite the first axial side SI and / or in an external surface 28 of the peripheral portion 22. In the illustrated example, a fluidic outlet 16B is arranged at the longitudinal end of the peripheral portion 22 on the second axial side S2, while two other fluidic outlets 16A and 16C are defined around an external surface 28 of the peripheral portion 22.

[0066] To connect the central part 20 and peripheral part 22 by allowing rotational guidance of one relative to the other, the device 10 includes two bearings 110A, 110B, for example rolling bearings, radially interposed between the central part 20 and the peripheral part 22, axially on either side of the internal annular space 23. Each of these bearings includes an inner ring 112A, 112B mounted on the central part 20, an outer ring 114A, 114B mounted in the peripheral part 22, and an annular row of rolling elements 116 interposed between the inner ring 112A, 112B and the outer ring 114A, 114B.

[0067] II. Central Part

[0068] The central part 20 comprises a main portion 30 defining the aforementioned external surface 20A, and, at one end of this located on the first axial side SI, the aforementioned connecting portion 32, and at another end of this located on the second axial side S2, a trunnion 34. The external surface 20A is, for example, separated from the connecting portion 32 by a shoulder 35B, while the trunnion 34 is separated from the external surface 20A by a shoulder 35A.

[0069] The inner ring 112A of the bearing 110A is, for example, axially mounted against the shoulder 35A in the direction of the first axial side SI. The inner ring 112B of the bearing 11OB is, for example, axially mounted against the shoulder 35B in the direction of the first axial side SI.

[0070] The central portion 20 generally comprises the first fluidic paths FP1A-FP1C, configured to connect the system's fluidic inlets 14A-14C to the transfer chambers 24A-24C, respectively, through the external surface 20A of the central portion 20. The means for achieving this result will not be described here and are outside the scope of the invention. Examples of configurations for the central portion are detailed in the patent application filed in France on October 20, 2023, under number FR2311395.

[0071] III. Peripheral part

[0072] With further reference to Figure 1, the peripheral part 22 generally comprises a bushing 50 (forming a main body of the peripheral part 22), and two rings, hereinafter referred to as transfer rings 70A, 70B.

[0073] III. A Socket

[0074] With particular reference to figure 2, the socket 50 has an internal surface with a geometry of revolution about the axis 8, for example cylindrical, hereafter referred to as the internal annular surface of the socket 52.

[0075] The internal annular surface of the socket 52 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 internal annular surface of the socket 52 thus has two shoulders 52D, 52E which axially delimit the intermediate portion 52C.

[0076] The sleeve 50 further comprises an annular rib 56, formed in radial projection inwards in the intermediate portion 52C, thus dividing the latter into a first part 52C1 located on the first axial side SI and a second part 52C2 located on the second axial side S2 (Figure 2). The rib 56 has two opposing flanks 56A, 56B connected to each other by an internal end surface 58 with a geometry of revolution, for example cylindrical, which helps to define the intermediate portion 52C of the internal annular surface of the sleeve 52, between the first and second parts 52C1, 52C2 of the latter.

[0077] Furthermore, the bushing 50, for example, has a radial annular flange 62 intended for its attachment to the turbomachine rotor.

[0078] The socket 50 comprises fluidic paths from socket BFP-A to BFP-C which respectively contribute to defining each of the second fluidic paths FP2A-FP2C (Figure 2). Each of these fluidic paths from socket BFP-A to BFP-C includes at least one corresponding fluidic passage 64, or preferably a corresponding series of such fluidic passages 64. These fluidic passages 64 each have an internal end 66 (Figure 2) opening through the intermediate portion 52C of the internal annular surface of the socket 52, and an opposite end connected to - or forming - one of the corresponding fluidic outlets 16A-16C.

[0079] In the illustrated example concerning a three-way fluidic device, the aforementioned fluidic passages are distributed, for example, into a first series 64A of fluidic passages distributed annularly around the axis 8 and opening into the first part 52C1 of the intermediate portion of the internal annular surface of the sleeve so as to constitute a first fluidic path of the sleeve BFP-A, a second series 64B of fluidic passages distributed annularly around the axis 8 and opening into the second part 52C2 of the intermediate portion of the internal annular surface of the sleeve so as to constitute a second fluidic path of the sleeve BFP-B, and a third series 64C of fluidic passages distributed annularly around the axis 8 and opening through the internal end surface 58 of the rib 56 so as to constitute a third fluidic path of the sleeve BFP-C.In particular, the fluid passages of the third series 64C open into the transfer chamber 24C.

[0080] Furthermore, the outer ring 114A of the bearing 110A is, for example, axially mounted against the shoulder 52D in the direction of the second axial side S2. The outer ring 114B of the bearing 110B is, for example, axially mounted against the shoulder 52E in the direction of the first axial side SI. The peripheral part 22 is thus axially sandwiched between the two bearings 110A and 110B. The assembly thus formed is, for example, axially tightened by means of a nut 117 mounted on the axial end of the journal 34.

[0081] The outer rings 114A, 114B of the bearings have respective faces forming two shoulders 118A, 118B extending radially inward from the inner annular surface of the bushing 52, to the axial ends of the intermediate portion 52C of the inner annular surface of the bushing 52 (figure 2).

[0082] Alternatively, such shoulders 118A, 118B can be formed by structures other than outer bearing rings.

[0083] III. B Transfer Rings

[0084] The two transfer rings 70A, 70B (visible in Figure 1, and of which one 70B is visible in isolation in Figures 4A, 4B and 5) are made up of annular bodies which generally have respective external surfaces 72 which delimit them on the radially external side, and respective internal surfaces 74 which delimit them on the radially internal side and which, according to the terminology adopted in this description, form corresponding parts of the internal surface 22A of the peripheral part 22. In addition, the annular body forming each of the transfer rings 70A, 70B has two opposing flanks 75e and 75i which connect to each other the external surface 72 and internal surface 74 of the ring in question (Figure 1).For the purposes of this description, the flanks 75e are those located relatively close to the axial ends of the device 10 while the flanks 75i are those located relatively far from the axial ends of the device 10, i.e. towards the axial center of the internal annular space 23.

[0085] In cases where, as in the example described, the internal annular surface of the bushing 52 is provided with the rib 56, the latter is arranged axially between the two transfer rings 70A, 70B. Thus, the internal end surface 58 of the rib 5, together with the internal surfaces 74 of the rings, contributes to defining the internal surface 22A of the peripheral part. Furthermore, the flanks 75i are, in such cases, arranged opposite the flanks 56A, 56B of the rib 56.

[0086] The two transfer rings 70A, 70B have the main functions of: - participating in fluidly connecting at least some of the first fluidic paths

[0087] FP1A, FP1B (defined within the central part 20) to BFP- socket fluidic paths

[0088] A, BFP-B corresponding (defined within socket 50); and

[0089] - to achieve dynamic sealing around the external surface 20A of the central part 20, at the axial ends of the internal annular space 23, in the manner of hydrodynamic bearings.

[0090] To perform the first function mentioned above, each of the transfer rings 70A, 70B is arranged so as to externally delimit a corresponding part of the internal annular space 23 including one of the corresponding transfer chambers 24A, 24B.

[0091] In addition, each transfer ring 70A, 70B has at least one - and for example several - fluidic passages 76A, 76B, hereinafter referred to as ring fluidic passages, each having an internal end 78 (figure 5) which opens, through the internal surface 74 of the ring, into a corresponding transfer chamber 24A, 24C (figure 1).

[0092] In addition, the fluid passages 76A of the transfer ring 70A each have an external end 80 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 transfer ring 70B each have an external end 80 opening through the external surface 72 of the ring 70B, opposite the second series 64B of fluid passages of the sleeve 50. For this purpose, the respective external surfaces 72 of the transfer rings 70A, 70B are arranged opposite the portions of the internal annular surface of the sleeve 52 where the fluid passages 64A, 64B of the sleeve 50 open, in this case opposite the first and second parts 52C1, 52C2 of the intermediate portion 52C of the internal annular surface of the sleeve 52.

[0093] To perform the second function mentioned above, the two transfer rings 70A, 70B are mounted radially floating between the external surface 20A of the central part 20 and the internal annular surface of the sleeve 52. To ensure good mechanical decoupling of the transfer rings 70A, 70B from the sleeve 50 and the central part 20, the transfer rings 70A, 70B are dimensioned so that, in a nominal position centered about the axis 8, an external radial clearance RI (Figure 1) exists between each transfer ring 70A, 70B and the internal annular surface of the sleeve 52, while an internal radial clearance R2 exists between each transfer ring 70A, 70B and the external surface 20A of the central part 20. An external annular space 82, having as its radial extent the external radial clearance RI, is thus defined between each of the transfer rings 70A, 70B and the internal annular surface of the 52 socket.Furthermore, for each of the transfer rings 70A, 70B, the aforementioned corresponding part of the internal annular space 23 (delimited by the transfer ring considered) has a radial extent equal to the internal radial clearance R2.

[0094] In particular, to guarantee the radial buoyancy of the transfer rings 70A, 70B and to optimize the dynamic sealing provided by the latter around the external surface 20A of the central part, the external radial clearance RI defined between each transfer ring 70A, 70B and the internal annular surface of the bushing 52 is greater than the internal radial clearance R2 defined between each transfer ring 70A, 70B and the external surface 20A of the central part 20.

[0095] In cases where, as in the example described, the internal annular surface of the bushing 52 is provided with the rib 56, the latter is arranged axially between the two transfer rings 70A, 70B, as already indicated. A certain axial clearance is provided between the rib 56 and each of the transfer rings 70A, 70B to facilitate the mechanical decoupling of the transfer rings 70A, 70B from the bushing 50, allowing for a floating mounting of the transfer rings 70A, 70B.

[0096] Furthermore, return means are provided to axially load each transfer ring 70A, 70B against the corresponding outer bearing ring 114A, 114B, thus establishing a static (or quasi-static) sealing contact between each transfer ring 70A, 70B and the corresponding shoulder 118A, 118B (the latter being formed in this case by the corresponding outer bearing ring 114A, 114B). The transfer rings 70A, 70B thus ensure the sealing of the external annular space 82 defined between the external surface 72 of each of the rings and the intermediate portion 52C of the internal annular surface of the bushing 52, at the axial ends of this intermediate portion 52C.

[0097] In the illustrated example, the return means comprise compression springs 120 (Figures 1, 4A-4B and 5) axially interposed between each transfer ring 70A, 70B and the rib 56, more precisely between each of the flanks 56A, 56B of the rib 56 and the flank 75i of each of the transfer rings 70A, 70B. In this example, each transfer ring 70A, 70B is stressed by several such compression springs 120 regularly distributed around the axis 8.

[0098] Shoulders 118A, 118B can each be provided with a surface coating, for example a chromium or tungsten carbide-based coating, designed to harden the contact area with the corresponding transfer ring while ensuring an optimal surface condition to limit fluid leakage through possible roughness and form defects on the 75th flank of the transfer ring.

[0099] Due to the axial spacing between each transfer ring 70A, 70B and the rib 56, the flanks 75i of the rings are exposed to fluid pressure.

[0100] In particular, the transfer rings 70A, 70B are advantageously shaped so that their flanks 75i are more exposed to fluid pressure than their opposite flanks 75e. For this purpose, the flank 75e of each of the transfer rings 70A, 70B has, for example, a circumferential rib 122 formed at the radially external end of the flank 75e, axially projecting from a radially internal portion 124 of the flank 75e, to form the bearing surface of the transfer ring in question against the corresponding outer bearing ring 114A, 114B (Figures 1 and 5). The radially internal portion 124 of the flank 75e is therefore axially recessed with respect to the bearing surface defined by the circumferential rib 122. The radially internal portion 124 of the flank 75e is thus the only part of the flank 75e that may be exposed to fluid pressure.The fluid pressure thus contributes to the axial loading of the transfer rings 70A, 70B respectively on the outer bearing rings 114A, 114B, and therefore to maintaining the static sealing contact between each transfer ring 70A, 70B and the corresponding outer bearing ring 114A, 114B, from the moment the system is pressurized. Of course, such axial loading of the transfer rings 70A, 70B by the fluid pressure can also be achieved in embodiments not including a rib 56.

[0101] Furthermore, angular indexing means are provided to angularly index each transfer ring 70A, 70B relative to the bushing 50, that is to say to ensure that each transfer ring 70A, 70B is rotationally fixed, or substantially rotationally fixed, to the bushing 50.

[0102] Thus, in the case where, as in the example described, the bushing 50 is intended to be integral with a rotor, the angular indexing means ensure that each transfer ring 70A, 70B rotates in unison with the bushing 50 and the rotor.

[0103] In the illustrated example, with reference to Figures 1 and 3-5, the angular indexing means comprise, for each transfer ring 70A, 70B, an axial pin 130 rigidly fixed to the transfer ring 70A, 70B in question and axially engaged, with a transverse clearance T1 (Figure 3), in a corresponding groove 132 formed in the rib 56 (Figure 2). With reference to Figures 1-3, such a groove 132 is a longitudinal groove with an inverted U-shaped cross-section, i.e., open radially inward. Furthermore, the groove 132 has one axial end open toward the corresponding transfer ring 70A, 70B, while the opposite axial end of the groove, located toward the interior of the rib 56, is closed, the groove 132 being blind in the axial direction.Each axial pin 130 is, for example, attached to the annular body of the transfer ring 70A, 70B by being partially engaged in an opening formed in the corresponding flank 75i of the ring, for example by shrink fitting. Alternatively, each axial pin 130 can be formed as a single piece with the annular body of the corresponding transfer ring 70A, 70B.

[0104] An inverse configuration of the angular indexing means is of course possible as an alternative, the axial pins 130 being in this case integral with the rib 56, and the grooves 132 being in this case formed in the transfer rings 70A, 70B.

[0105] Due to the transverse clearance Tl between each axial pin 130 and the corresponding groove 132 (Figure 3), the contact between each axial pin 130 and the groove 132 during operation is a linear contact, which ensures the buoyancy of the transfer rings 70A, 70B. The angular indexing means, such as the axial pins 130 and grooves 132, are advantageously configured to maintain angular coincidence between the fluidic passages of the rings 76A, 76B and the corresponding fluidic paths of the sleeves BFP-A, BFP-B. Thus, in the illustrated example, the axial pins 130 and grooves 132 are arranged so that the external end 80 of each of the fluidic passages of ring 76A, 76B opens radially opposite the internal end 66 of a corresponding fluidic passage 64 of the sleeve 50.The angular indexing means thus allow efficient fluid transmission between each transfer ring 70A, 70B and the bushing 50, even in the absence of provisions allowing annular distribution of the fluid between each transfer ring 70A, 70B and the bushing 50, such as grooves to enlarge the cross-section of the external annular space 82 at locations where the fluid passages 76A, 76B of the rings communicate with the fluid passages 64A, 64B of the bushing 50.

[0106] In general, the dynamic sealing provided by the transfer rings 70A, 70B allows the control of fluid leakage through the axial ends of the internal annular space 23. These fluid leaks are advantageously used to lubricate the bearings 110A, 110B and are, in this case, preferably limited to the flow rate necessary for this function.

[0107] In addition to ensuring the two functions explained above, the use of transfer rings 70A, 70B to partially define the internal surface 22A of the peripheral part 22 generally makes it easier to rectify the internal surface 22A and / or to apply a protective coating to it, by dividing it into several sections that can be treated independently of each other.Each transfer ring 70A, 70B has a smaller axial extent compared to the total axial extent of the internal surface 22A. Therefore, certain grinding tools and tools for spraying protective coatings, which would be unsuitable for processing the internal surface 22A as a whole due to its axial extent, can instead be used to process the internal surface 74 of each transfer ring 70A, 70B 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 internal annular surface of the sleeve 52, compared to the internal diameter of the internal surface 22A.

[0108] The limitation of the internal radial clearance R2 between surfaces 20A and 22A is thus facilitated. This results in the possibility of obtaining a satisfactory seal between the central part 20 and the peripheral part 22, even in cases where the overlap length, i.e., the axial extent of the internal annular space 23 defined between these parts, would be relatively small compared to what would be required in a device not employing such transfer rings. Furthermore, the reduction in the overlap length required to obtain a satisfactory seal offers, in particular, the advantage of reduced mass and size for the device 10.

[0109] Figures 6 to 8 illustrate a variant in which the angular indexing means comprise, for each transfer ring 70A, 70B, an axial key 134 extending outward from the transfer ring 70A, 70B and engaged radially, with a transverse clearance T2, in a corresponding groove 136 formed in the rib 56. The axial key 134 extends radially, for example, so as to present a radially internal end flush with the internal surface 74 of the transfer ring. A reverse configuration of such angular indexing means is, of course, also possible here.

[0110] The axial pin 130 of figures 1 and 3-5 and the axial key 134 of figures 6-8 are examples of axial lugs that can form the indexing means.

[0111] Other types of return means for axially loading each transfer ring 70A, 70B against the corresponding outer bearing ring 114A, 114B may also be provided within the scope of the invention, instead of or in addition to the compression springs 120 described above. These return means may thus include other types of springs, such as wave springs, or more generally other types of elastic parts such as Belleville washers or washers made of elastomer material. The return means may also include magnets configured to exert a magnetic force on each transfer ring 70A, 70B, loading the transfer ring 70A, 70B against the corresponding outer bearing ring 114A, 114B, in a manner analogous to that described above. Such a variant is particularly advantageous in cases where there is no rib 56.

[0112] IV. Manufacturing Process

[0113] A manufacturing process for device 10 generally includes the following steps:

[0114] A) make available the central part 20 and the peripheral part 22; then

[0115] 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 two-to-two the first fluidic paths FP1A, FP1B and the second fluidic paths FP2A, FP2B respectively.

[0116] Step B may include the implementation of a tight fit of the transfer rings 70A, 70B around the external surface 20A of the central part, in which case the process includes a subsequent running-in step C, consisting of rotating the central part 20 and the peripheral part 22 relative to create the internal radial clearance R2 by running in the respective surfaces of the transfer rings 70A, 70B and the external surface 20A of the central part 20, initially in tight contact around each other.

[0117] V. Implementation Procedure

[0118] A method for implementing a device of the type described above generally includes:

[0119] - selective fluid supply to the first fluidic paths FP1A-FP1C, via the fluidic inlets 14A-14C of the device;

[0120] - 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, up to the fluidic outlets 16A-16C of the device.

[0121] Furthermore, as explained above, the process includes the sealing of the external annular space 82 defined between each of the transfer rings 70A, 70B and the internal annular surface of the sleeve 52, by the static (or quasi-static) contact between the transfer ring 70A, 70B considered and the corresponding shoulder 118A, 118B, ensured by the return means (such as the compression springs 120).

[0122] The process further includes establishing a dynamic seal between each of the transfer rings 70A, 70B and the external surface 20A of the central part 20, by means of the floating mounting of the transfer rings 70A, 70B around the external surface 20A, allowing the transfer rings 70A, 70B to act in the manner of hydrodynamic bearings.

[0123] Where appropriate, the process further advantageously includes the lubrication of each of the bearings 110A, 110B by an axial leakage of the fluid through said dynamic seal, from the corresponding transfer chamber 24A, 24B.

[0124] VI. Turbomachine

[0125] Figure 9 illustrates a turbomachine 310, for example a twin-spool turbofan engine for aircraft, generally comprising a fan 312 for the intake of an airflow Fl which divides downstream of the fan into a primary flow F2 flowing in a primary flow channel, hereafter referred to as the primary flow PV, and a secondary flow F3 flowing in a secondary flow channel, hereafter referred to as the secondary flow SV, arranged around the primary flow PV.

[0126] The turbomachine comprises, for example, a low-pressure compressor 314, a high-pressure compressor 316, a combustion chamber 318, a high-pressure turbine 320, and a low-pressure turbine 322, which together define the primary flow PV. 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 a shaft 328 of the turbomachine.

[0127] The turbomachine includes a device 10 of the type described above, with an axis 8 for example coinciding with the axis 328 of the turbomachine 310. A stator 330 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 340 of the turbomachine is integral with the other part, in this case the peripheral part 22, of the device.

[0128] Device 10, schematically illustrated in Figure 9, is arranged, for example, so that its fluidic outlets 16A-16C are connected to fluidic chambers of actuators mounted on the aforementioned rotor 340 to enable the control of such actuators. In particular, the device is, for example, of the type commonly known as an OTB (Oil Transfer Bearing) and is designed to supply a cylinder controlling the pitch of the fan blades or, more generally, one or more propellers, as well as a blade safety actuator.

Claims

Demands 1. Device (10) for transferring fluid through multiple channels, comprising: - a central part (20) having an external surface (20A) with a geometry of revolution about an axis (8); - a peripheral part (22) arranged around the external surface (20A) of the central part, with the ability to rotate relative to the latter along the axis (8); an internal annular space (23) defined between the external surface (20A) of the central part and the peripheral part (22), and transfer chambers (24A to 24C) defined as annular portions of the internal annular space (23); wherein: - the central part (20) defines first fluidic paths (FP1A to FP1C) connecting respectively 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 respectively fluidic outputs (16A to 16C) of the device to the transfer chambers (24A to 24C); - the peripheral part (22) includes a sleeve (50) having an internal annular sleeve surface (52) and comprising sleeve fluidic paths (BFP-A to BFP-C) each constituting a part of one of the corresponding second fluidic paths (FP2A to FP2C); - the peripheral part (22) comprises two structures forming respectively two shoulders (118A, 118B) projecting radially inwards from the internal annular surface of the socket (52); - the peripheral part (22) comprises two transfer rings (70A, 70B) respectively mounted radially floating between said external surface (20A) of the central part (20) and the internal annular surface of the socket (52) such that each of the transfer rings (70A, 70B) externally delimits a corresponding part of the internal annular space (23) including one of the corresponding transfer chambers (24A, 24B); - when each transfer ring (70A, 70B) is in a nominal position centered along the axis (8), an external radial clearance (RI) defined between each transfer ring (70A, 70B) and the internal annular surface of the bushing (52) is greater than an internal radial clearance (R2), defined between each transfer ring (70A, 70B) and the external surface (20A) of the central part (20) and forming said corresponding part of the internal annular space (23); the peripheral part (22) includes return means for axially stressing each transfer ring (70A, 70B) against one of the two corresponding shoulders (118A, 118B); Each transfer ring (70A, 70B) has at least one ring fluidic passage (76A, 76B) forming part of one of the corresponding second fluidic paths (FP2A, FP2B) and communicating with one of the corresponding bushing fluidic paths (BFP-A, BFP-B).

2. Device according to claim 1, wherein the internal annular surface of the sleeve (52) is provided with an annular rib (56) arranged axially between the two transfer rings (70A, 70B) and spaced from the latter.

3. Device according to claim 2, wherein one of the bushing fluidic paths (BFP-C), other than those communicating with the ring fluidic passages (76A, 76B), opens through an internal end surface (58) of the rib (56).

4. Device according to claim 2 or 3, wherein the return means comprise compression springs (120) axially interposed between each transfer ring (70A, 70B) and the rib (56).

5. Device according to any one of claims 1 to 4, wherein the peripheral part (22) comprises angular indexing means for angularly indexing each transfer ring (70A, 70B) relative to the bushing (50) 6. Device according to any one of claims 2 to 4 combined with claim 5, wherein the angular indexing means comprise, for each transfer ring (70A, 70B), at least one axial lug (130; 134) rigidly attached to one of the transfer ring (70A, 70B) considered and the rib (56), axially engaged with a transverse clearance (T1; T2) in a corresponding groove (132; 136) formed in the other of the transfer ring (70A, 70B) considered and the rib (56).

7. Device according to claim 5 or 6, wherein the angular indexing means are configured to maintain angular coincidence between the ring fluidic passages (76A, 76B) and the corresponding bushing fluidic paths (BFP-A, BFP-B).

8. Device according to any one of claims 1 to 7, wherein two bearings (110A, 110B), radially interposed between the central part (20) and the bushing (50) axially on either side of the internal annular space (23) to guide said central (20) and peripheral (22) parts in rotation relative to each other, comprise respective outer bearing rings (114A, 114B) rigidly mounted in the bushing (50) and constituting said structures forming said shoulders respectively.

9. Aircraft turbomachine (310), comprising at least one device (10) according to any one of claims 1 to 8, a stator (330) integral with one of the central (20) and peripheral (22) parts of the device, and a rotor (340) integral with the other of the central (20) and peripheral (22) parts of the device.

10. A method for implementing a device (10) according to any one of claims 1 to 8 comprising: - selective fluid supply of 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), up to the fluidic outlets (16A to 16C) of the device; - the tight closure of an external annular space (82), defined between each of the transfer rings (70A, 70B) and the internal annular surface of the socket (52), by a static contact between the transfer ring (70A, 70B) considered and the corresponding shoulder (118A, 118B) ensured by the return means; - for each of the transfer rings (70A, 70B), the establishment of a dynamic seal between the transfer ring (70A, 70B) considered and the external surface (20A) of the central part (20) during the circulation of the fluid through the corresponding transfer chamber (24A, 24B).

11. Method according to claim 10, wherein the device (10) is a device according to any one of claims 5 to 7, and the angular indexing means establish linear contacts between each transfer ring (70A, 70B) and the bushing (50).

12. Method according to claim 10 or 11, wherein the device (10) is a device according to claim 8, the method comprising the lubrication of each of the bearings (110A, 110B) by an axial leakage of the fluid through said dynamic seal, from the corresponding transfer chamber (24A, 24B).

13. A method for manufacturing a device (10) according to any one of claims 1 to 8 comprising at least 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 (FP1A to FP1C) and the second fluidic paths (FP2A to FP2C) in pairs.

14. Method according to claim 13, wherein step B comprises implementing a tight fit of the transfer rings (70A, 70B) around the external surface (20A) of the central part, the method comprising a subsequent step C consisting of rotating the central part (20) and the peripheral part (22) relative to create the internal radial clearance (R2) by lapping each transfer ring (70A, 70B) and the external surface (20A) of the central part (20).

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