RING FIXING DEVICE FOR AN AIRCRAFT TURBOMACHINE

Abstract

A device (88) for securing coaxial annular parts for an aircraft turbomachine (10), this device comprising: - at least one backing plate (90) extending circumferentially around a principal axis (A) of the parts and applied radially against a first part (34), - an annular plate (92) fixed to a second part (36) and extending radially outwards from the principal axis (A) at the level of said at least one backing plate (90), and - clamping elements (94) carried by the annular plate (92) and capable of applying a clamping force in a radial direction on the backing plate (90), each of these clamping elements (94) being movable about a clamping axis (B) parallel to said principal axis (A), independently of each other. Figure for the abbreviation: Figure 2

Description

Title of the invention: DEVICE FOR ATTACHING RINGS TO AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to a device for fixing coaxial annular parts for an aircraft turbomachine, as well as a module and a turbomachine comprising such a device. Technical background

[0002] An aircraft turbomachine includes a gas generator which conventionally comprises, from upstream to downstream, with reference to the flow of gases in the turbomachine, at least one compressor, an annular combustion chamber and at least one turbine.

[0003] In the case of a twin-spool turbofan engine, with low-pressure and high-pressure components respectively, the gas generator comprises successively a low-pressure compressor, a high-pressure compressor, the combustion chamber, a high-pressure turbine, and a low-pressure turbine. The gas generator defines a first annular flow path of gas, called the primary flow, which passes through the compressors, the combustion chamber, and the turbines.

[0004] The rotor of the high-pressure compressor is connected to the rotor of the high-pressure turbine by a high-pressure shaft. The rotor of the low-pressure compressor is connected to the rotor of the low-pressure turbine by a low-pressure shaft which passes through the high-pressure shaft and drives a shaft of a propulsion propeller generally located upstream of the gas generator.

[0005] A turbomachine is formed by the assembly of several parts that generally have rotational symmetry about the axis of the turbomachine. For example, annular parts are known to be coaxially fixed to one another by annular flanges. The parts have flanges that are axially fixed to one another by screws or bolts that pass through axial holes in the flanges.

[0006] Some parts overlap radially or are engaged with one another and must be radially clamped together. One solution for radially clamping one annular part against another annular part generally involves using radially oriented screws or bolts tightened from the outside of the parts. However, this solution is not always feasible because the environment around the parts may be relatively cluttered, preventing the installation and handling of these screws or bolts.

[0007] The invention provides a solution to this problem, which is simple, effective and economical. Summary of the invention

[0008] The invention relates to a device for fixing coaxial annular parts for an aircraft turbomachine, this device comprising:

[0009] - at least one plywood extending circumferentially around an axis main part and applied radially against a first part,

[0010] - an annular plate fixed to a second part and extending radially towards the exterior relative to the main axis at the level of said at least one plywood, and

[0011] - clamping elements carried by the annular plate and capable of applying a clamping force in the radial direction on the plywood, each of these clamping elements being movable around a clamping axis parallel to said main axis, independently of each other, between a first non-clamping position in which it does not apply clamping force on the plywood, and a clamping position in which it applies said clamping force.

[0012] The invention addresses the problem mentioned above. Since the environment around the parts to be fixed can be cluttered, the invention proposes using clamping elements that rotate about clamping axes parallel to the main axis, and are therefore axially oriented. This ensures optimal radial clamping of the first part without the need for bulky and difficult-to-access radial elements.

[0013] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • the clamping elements are regularly distributed around said main axis; • the annular plate is fixed to the second part via at least one fluidic fitting of said circuit; • the fluidic fitting comprises a tubular sleeve oriented parallel to the main axis, and at least one external tab attached to the sleeve and extending in a radial plane to the main axis, the sleeve having a first end engaged in a housing of the second part and a second end, opposite to the first end, which is in fluidic communication with a pipe, said at least one tab having at least one orifice for the passage of a screw screwed into a hole in the second part; • the annular plate is axially interposed between said at least one leg and the second piece; • the clamping elements are housed at least partially in at least one recess in the second part; • each of the clamping elements includes an eccentric and a screw for retaining the eccentric on the annular plate, the eccentric being movable around the screw which is centered on the clamping axis; • a plain bearing is mounted between the screw and the eccentric; • the plain bearing is formed by a cylindrical ring, one end of which includes an external annular rim, the ring being axially clamped by the screw against the annular plate and the annular rim being separated by an axial clearance from the eccentric; • the eccentric includes a recessed or projecting indentation suitable for cooperating with a tool for rotating the eccentric around its clamping axis; • the imprint is of the hexagonal or six-sided type; • The recess is raised and hollow to internally receive the screw and the said ring; • the eccentric has an external periphery comprising at least one cam surface, this cam surface possibly comprising at least one sharp edge forming a hard point when rotating the eccentric around its clamping axis; • the clamping device comprises several plywood pieces arranged one after the other around the main axis; • said at least one plywood comprises two cylindrical sectors of different diameters and connected together by a truncated conical sector; • said first part is elastically deformable, particularly in compression, and is for example made of elastomer; • said second part is a casing;

[0014] — the annular plate is not sectorized;

[0015] — the annular plate is sectorized and comprises two sectors of 180° each.

[0016] The present invention also relates to a module for a turbomachine aircraft, comprising three coaxial annular pieces and a device as described above, the annular plate being fixed to one of the pieces, called second piece, and the plywood being clamped radially against another of the pieces, called first piece, which is interposed radially between the clamping elements and another piece, called third piece.

[0017] Advantageously, the annular plate is fixed to an annular flange of the second part, and the first part is radially interposed between the clamping elements and an annular flange of the third part.

[0018] The present invention also relates to an aircraft turbomachine, comprising at least one device or module as described above. Brief description of the figures

[0019] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0020] [Fig-1] [Fig.1] is a schematic half-view in axial cross-section of a turbomachine aircraft,

[0021] [Fig.2] [Fig.2] is a schematic perspective view of a device according to the invention for fixing annular parts;

[0022] [Fig.3] [Fig.3] is a schematic perspective and cross-sectional view of the fixing device of [Fig.2], the cross-section being made at the level of a sleeve of a fluidic fitting;

[0023] [Fig.4] [Fig.4] is a schematic perspective and cross-sectional view of the fixing device of [Fig.2], the cross-section being made at the level of a leg of the fluidic fitting;

[0024] [Fig.5] [Fig.5] is a schematic perspective and cross-sectional view of the fastening device of [Fig.2], the section being made at the level of a clamping element;

[0025] [Fig.6] [Fig.6] is a schematic perspective, cross-sectional and larger scale view of the clamping element of [Fig.5];

[0026] [Fig.7] [Fig.7] is a schematic perspective view of the fastening device of [Fig.2], and shows an assembly step;

[0027] [Fig.8] [Fig.8] is a schematic perspective and cross-sectional view of the fastening device of [Fig.2], and shows the assembly step;

[0028] [Fig.9] [Fig.9] is a schematic perspective view of the fastening device of [Fig.2], and shows a tightening step;

[0029] [Fig. 10a-10c] Figures 10a to 10c are schematic front views of one of the clamping elements of the fastening device of [Fig. 2], and show several positions of this element around its clamping axis; and

[0030] [Fig. 11] [Fig. 11] is a very schematic view of an alternative embodiment of the eccentric of the clamping element. Detailed description of the invention

[0031] Figure 1 describes a turbomachine 1 which conventionally comprises a rotation axis A, a fan S, a low-pressure compressor 1a, and a high-pressure compressor The high-pressure compressor (1b) and the high-pressure turbine (1d) are connected by a high-pressure shaft (2) and together form a high-pressure (HP) unit. The low-pressure compressor (la) and the low-pressure turbine (le) are connected by a low-pressure shaft (3) and together form a low-pressure (LP) unit.

[0032] The blower S is driven by a blower shaft 4 which is driven to the BP shaft 3 by means of a reducer 6. This reducer 6 is generally of the planetary or epicycloidal type.

[0033] The following description relates to a planetary type reducer in which the ring is mobile in rotation.

[0034] The reducer 6 is positioned in the upstream part of the turbomachine. A fixed structure schematically comprising, here, an upstream part 5a and a downstream part 5b which make up the motor or stator housing 5 is arranged to form an enclosure E surrounding the reducer 6. This enclosure E is here closed upstream by seals at the level of a bearing allowing the passage of the blower shaft 4, and downstream by seals at the level of the passage of the BP shaft 3.

[0035] [Fig.2] shows a module 30 of the turbomachine, this module 30 comprising coaxial annular parts, these parts being aligned on the same axis which is not visible in [Fig.2] and which may be the main axis A of the turbomachine 1 of [Fig.1].

[0036] In the example shown, the parts are annular bearing supports 32, 34, an annular housing 36, and an annular skirt 80.

[0037] A first annular bearing support 32 extends around the axis A and includes a first annular fixing flange 32a.

[0038] A second annular bearing support 34 extends around the axis A and includes a second annular fixing flange 34a. The flanges 32a, 34a extend radially outwards and are suitable for being applied axially against each other and fixed together by screws not shown.

[0039] An annular housing 36 extends around the axis A and the second bearing support 34 is fixed to this housing 36 by screws not shown.

[0040] The housing 36 includes a flange 36a onto which the flange 34a is applied and fixed. The flange 34a of the second bearing support 34 is axially interposed between the flange 32a of the first bearing support 32 and the flange 36a of the housing 36.

[0041] The annular skirt 80 extends around the flanges 32a, 34a and includes a first axial end 80a to the first bearing support 32 and a second axial end 80b fixed to the second bearing support 34.

[0042] The skirt 80 is made of a deformable material, preferably elastically deformable such as an elastomer. The skirt 80 is, for example, made of Viton®.

[0043] The skirt 80 is preferably fiber-reinforced. The fibers are preferably oriented in the axial direction so that the skirt 80 has a bending deformation capacity and a tensile strength.

[0044] The skirt 80 is preferably suitable for ensuring a seal around the flanges 32a, 34a, between the first and second bearing supports 32, 34.

[0045] In the example shown, the skirt 80 has a generally convex shape with a concavity oriented radially inwards. The skirt 80 can define a free annular cavity 82 around at least a portion of the bearing support 32 and / or the bearing support 34.

[0046] In the example shown, the first end 80a of the skirt 80 is fixed to an annular rib 84 of the first bearing support 32. This rib 84 extends radially outwards, here at an axial distance from the flange 32a.

[0047] The first end 80a of the skirt 80 is clamped against an annular face, here downstream, of the rib 84 by means of an annular plywood 86. This plywood 86 can be sectored to facilitate its assembly.

[0048] The plywood 86 is fixed to the rib 84 by screws (not shown) which pass through holes in the rib 84, the end 80a of the skirt 80 and the plywood 86.

[0049] In the example shown, the second end 80b of the skirt 80 is fixed to the flange 34a of the second bearing support 34.

[0050] More particularly, the second end 80b of the skirt 80 is radially clamped onto the flange 34a by means of a fastening device 88 according to the invention.

[0051] Figures 2 to 10c illustrate a first embodiment of a fastening device 88 for the skirt 80.

[0052] Essentially, the fastening device 88 comprises

[0053] - at least one 90 plywood extending circumferentially around axis A and applied radially against the second axial end 80b of the skirt 80,

[0054] - an annular plate 92 fixed to the annular housing 36 and extending radially towards the outside relative to axis A at the level of the 90 plywood, and

[0055] - clamping elements 94 carried by the annular plate 92 and capable of applying a clamping force in the radial direction on the 90 plywood.

[0056] Within the framework of the present invention, the skirt 80, the housing 36 and the bearing support 34 form respectively first, second and third parts.

[0057] Insofar as the plywood 90 must be capable of applying or transferring a radial force onto the skirt 80, it must retain the ability to move freely in the radial direction and therefore cannot be annular and continuous over 360°. It thus has a circumferential orientation. The number of plywood 90s is not limiting and can be 1, 2, 3 or 4 for example. When using two 90 or more plywood sheets, they are placed end to end around axis A.

[0058] In the example shown, the plywood 90 is not perfectly cylindrical. For example, it has a general flattened S-shape, as in Figures 2 and 5. In this case, it may comprise two cylindrical sectors 90a and 90b of different diameters connected by a frustoconical sector 90c. The cylindrical sector 90b with the smaller diameter (with respect to axis A) is located downstream of the cylindrical sector 90a with the larger diameter (with respect to axis A). In the variant shown in Figures 3 and 4, the plywood 90 comprises only two sectors: a frustoconical sector 90c upstream and a cylindrical sector 90b downstream, with the cylindrical sector 90b defining the smaller diameter of the plywood, measured from axis A.

[0059] The drawings show that these particular shapes of the plywood 90 allow it to conform as closely as possible to the shape of the outer periphery of the flange 34a around which the plywood 90 is arranged. It can also be seen that the end 80b of the skirt 80 is radially interposed between the plywood 90 and the outer periphery of the flange 34a and adopts a similar shape due to the elastic deformation capacity of the skirt 80.

[0060] The plate 92 can be non-sectorized and therefore continuous over 360° around the main axis A. It is preferably flat and extends in a radial plane to the main axis A. Alternatively, the plate 92 could be sectorized and comprise two sectors of 180° each, to facilitate its assembly.

[0061] The plate 92 includes axially through holes 96 which are of three types: first holes 96a, second holes 96b and third holes 96c.

[0062] The first and second ports 96a, 96b allow for the mounting of at least one fluid connection 98 of said supply circuit 40 (Figures 3 and 4). The number of fluid connection(s) 98 is not limited.

[0063] Advantageously, it is this fluidic fitting 98 which allows the annular plate 92 to be fixed to the annular housing 36.

[0064] The fluidic fitting 98 comprises a tubular sleeve 100 oriented parallel to the axis A, and at least one external tab 102 integral with the sleeve 100 and extending in a radial plane to the axis A.

[0065] The fluidic fitting 98 can be formed from a single piece.

[0066] The sleeve 100 has a first end 100a engaged in a housing 103 of the annular casing 36 through the first orifice 96a or one of the first orifices 96a of the plate 92 ([Fig. 3]). The drawing shows that this first end 100a may be of the male type and may carry an annular sealing gasket 101 which cooperates with the female-type housing 103 of the casing 36.

[0067] The annular plate 92 is axially intercalated between the or each leg 92 and the annular housing 36.

[0068] The sleeve 100 has a second end 100b, opposite the first end 100a, which is in fluidic communication with a conduit 104. It can be seen in the drawing that the conduit 104 can be of the male type and can carry an annular sealing gasket 101' which cooperates with the second end 100b of the female type of the sleeve 100.

[0069] The or each leg 102 has at least one orifice 106 for the passage of a screw 108 screwed into a hole 110 of the annular housing 36 through the second orifice 96b or one of the second orifices 96b of the plate 92 ([Fig.4]).

[0070] The third orifices 96c of the plate 92 are used for mounting the clamping elements 94.

[0071] The clamping elements 94 are preferably regularly distributed around the axis A ([Fig.5]).

[0072] The number of clamping elements 94 can be equal to the number of fusible screws 42 in the module.

[0073] Each of the clamping elements 94 is movable around a clamping axis B parallel to the axis A, independently of each other, between a first non-clamping position in which it does not apply any clamping force on the plywood 90, and a clamping position in which it applies a clamping force on the plywood 90.

[0074] We can see in [Fig.5] in particular that the clamping elements 94 are housed at least in part in at least one recess 112 of the annular housing 36.

[0075] As can be seen more clearly in [Fig.6], each of the clamping elements 94 includes an eccentric 114 and a screw 116 for retaining the eccentric 114 on the annular plate 92, the eccentric 114 being movable around the screw 116 which is centered on the clamping axis B.

[0076] The screw 116 passes through one of the aforementioned third holes 96c of the annular plate and is screwed into a nut 118 which can be crimped into the hole 96c, which can be captive mounted, or simply attached.

[0077] A plain bearing 120 is advantageously mounted between the screw 116 and the eccentric 114. This plain bearing 120 can be formed by a cylindrical ring 122 having one end comprising an external annular rim 124. The ring 120 is adapted to be axially clamped by the screw 116 against the annular plate 92 and the annular rim 124 is adapted to be separated by an axial clearance J1 from the eccentric 114 in order to allow it freedom of movement in particular in rotation around the clamping axis B.

[0078] The eccentric 114 includes a recessed or projecting imprint 126 adapted to cooperate with a tool for rotating the eccentric 114 about its axis of clamping B. This 126 socket can be of the hexagonal or six-sided type, as in the example shown.

[0079] This recess 126 is for example projecting and is preferably hollow to receive internally the screw 116 and the ring 120, as illustrated in the drawings.

[0080] The eccentric 114 has an external periphery comprising at least one cam surface 128.

[0081] In the embodiment of figures 2 to 10c, the cam surface 128 has at least one sharp edge 130 forming a hard point when the eccentric 114 is rotated around its clamping axis B. The or each sharp edge is straight and extends parallel to the clamping axis B.

[0082] The cam surface 128 may include chamfered edges 132 between two adjacent sharp edges 130. In the example illustrated in Figures 2 to 10c, the cam surface 128 includes a cylindrical surface 134 extending over approximately 180° and comprising, over the remaining 180°, three consecutive chamfered edges 132 connected to each other and to the cylindrical surface 134 by sharp edges 130.

[0083] The radial distance RI between the clamping axis B and the cylindrical surface 134 varies along this surface 134 and is maximum at the circumferential ends of the surface 134 (Figure 10a). The radial distance R2 between the intermediate chamfered face 132 and the clamping axis B is greater than the radial distances R3 between the other two chamfered faces 132 and the clamping axis B (Figure 10a).

[0084] In the embodiment shown in [Fig. 11], the cam surface 128 does not have a sharp edge and has a generally elliptical or teardrop shape. The radial distance between the clamping axis B and the surface 128 varies around the axis B and also has a maximum.

[0085] We will now describe the assembly of the fastening device 88 according to the invention with reference to figures 7 to 10c.

[0086] The annular plate 92 is first attached to the housing 36 by the fluidic fitting(s) 98. The clamping elements 94 are mounted on the annular plate 92 as shown in the drawings, by inserting each screw 116 into the ring 120 and then inserting the assembly into the recess of the eccentric 114. The screw 116 is screwed into the nut 118 so as to axially clamp the ring 120 against the annular plate 92. Alternatively, the mounting of the clamping elements 94 on the plate 92 could be carried out before the plate 92 is attached to the housing 36 by the fluidic fittings 98.

[0087] The eccentrics 114 are then in the unclamping position of Figure 10a in which they do not apply any clamping force on the plywood 90. It can be seen in this figure that the cylindrical surface 134 is opposite the plywood 90 and is separated by a radial clearance J2 from the plywood 90. In other words, the radial distance between the clamping axis B and the plywood 90 is greater than the aforementioned distance RI.

[0088] Each of the eccentrics 114 is then rotated about its clamping axis B to a second clamping position illustrated in Figure 10c, in which it applies a clamping force to the plywood 90 to radially clamp the skirt 80 against the flange 34a. This figure shows that the intermediate chamfered edge 132 is radially pressed against the plywood 90. In other words, the aforementioned radial distance between the clamping axis B and the plywood 90 is less than the aforementioned distance R2.

[0089] To move from the unclamped position in Figure 10a to the clamped position in Figure 10c, the eccentric 114 passed through intermediate positions such as those illustrated in Figures 9 and 10b, for example. In Figure 10b, for example, one of the chamfered edges 132 can be seen opposite and at a distance from the plywood 90, the aforementioned radial distance between the clamping axis B and the plywood 90 being greater than the aforementioned distance R3.

[0090] Although Figures 2 and following illustrate a particular use of the fastening device 88 according to the invention, it is understood that this device can be used for fastening other annular and coaxial parts.

Claims

Demands

1. A device (88) for securing coaxial annular parts for an aircraft turbomachine (10), said device comprising: - at least one plywood (90) extending circumferentially around a principal axis (A) of the parts and applied radially against a first of the parts, - an annular plate (92) fixed to a second of the parts (36) and extending radially outwards with respect to the principal axis (A) at the level of said at least one plywood (90), and - clamping elements (94) carried by the annular plate (92) and capable of applying a clamping force in a radial direction on the plywood (90), each of these clamping elements (94) being movable about a clamping axis (B) parallel to said principal axis (A), independently of each other, between a first non-clamping position in which it does not apply a clamping force on the plywood (90),and a clamping position in which it applies said clamping force.

2. Device (88) according to claim 1, wherein the clamping elements (94) are regularly distributed around said axis (A).

3. Device (88) according to claim 1 or 2, wherein the annular plate (92) is fixed to the second part (36) via at least one fluidic fitting (98).

4. Device (88) according to claim 3, wherein the fluidic fitting (98) comprises a tubular sleeve (100) oriented parallel to the main axis (A), and at least one external tab (102) integral with the sleeve (100) and extending in a radial plane to the main axis (A), the sleeve (100) having a first end (100a) engaged in a housing (103) of the second piece and a second end (100b), opposite the first end (100a), which is in fluidic communication with a conduit (104), said at least one tab (102) having at least one orifice (106) for the passage of a screw (108) screwed into a hole (110) of the second piece.

5. Device (88) according to claim 4, wherein the annular plate (92) is axially intercalated between said at least one leg (102) and the second piece.

6. Device (88) according to any one of the preceding claims, wherein the clamping elements (94) are housed at least in part in at least one recess (112) of the second part.

7. Device (88) according to any one of the preceding claims, wherein each of the clamping elements (94) comprises an eccentric (114) and a screw (116) for retaining the eccentric (114) on the annular plate (92), the eccentric (114) being movable around the screw (116) which is centered on the clamping axis (B).

8. Device (88) according to claim 7, in which a plain bearing (20) is mounted between the screw (116) and the eccentric (114).

9. Device (88) according to claim 8, in which the plain bearing (120) is formed by a cylindrical ring (122) one end of which includes an external annular rim (124), the ring (122) being axially clamped by the screw (116) against the annular plate (92) and the annular rim (124) being separated by an axial clearance (J2) from the eccentric (114).

10. Device (88) according to any one of claims 7 to 9, wherein the eccentric (114) comprises a recessed or projecting imprint (126) adapted to cooperate with a tool for rotating the eccentric (114) around its clamping axis (B).

11. Device (88) according to claim 10, wherein the impression (126) is of the hexagonal or six-sided type.

12. Device (88) according to claim 10 or 11, depending on claim 9, wherein the recess (126) is projecting and hollow to internally receive said screw (116) and said ring (120).

13. Device (88) according to any one of claims 7 to 12, wherein the eccentric (114) has an external periphery comprising at least one cam surface (128), this cam surface (128) being able to comprise at least one sharp edge (130) forming a hard point when rotating the eccentric (114) around its clamping axis (B).

14. Device (88) according to any one of the preceding claims, wherein the clamping device (88) comprises several plywood pieces (90) which are arranged one after the other around the main axis (A).

15. Device (88) according to any one of the preceding claims, wherein said at least one plywood (90) comprises two sectors cylindrical (90a, 90b) of different diameters and connected together by a truncated conical sector (90c).

16. Device (88) according to any one of the preceding claims, wherein said first part is elastically deformable, in particular in compression, and is for example made of elastomer.

17. Device (88) according to any one of the preceding claims, wherein said second part is a housing (36).

18. Module (30) for an aircraft turbomachine, comprising three coaxial annular pieces and a device (88) according to any one of the preceding claims, the annular plate (92) being fixed to one of the pieces, called the second piece, and the plywood (90) being radially clamped against another of the pieces, called the first piece, which is radially interposed between the clamping elements (94) and another piece, called the third piece.

19. Module (30) according to claim 18, wherein the annular plate (92) is fixed to an annular flange (36a) of the second part, and the first part is radially interposed between the clamping elements (94) and an annular flange (34a) of the third part.

20. Turbomachine (10) for an aircraft, comprising at least one device (88) according to any one of claims 1 to 17 or a module according to claim 18 or 19.

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