ANNULAR PIECE FOR AN AIRCRAFT TURBOMACHINE

Abstract

Part for an aircraft turbomachine, this part comprising an annular flange (20, 22, 40) comprising: - orifices (50) opening axially and capable of receiving fixing elements, - an annular row of solid parts (P1) which comprise the aforementioned orifices (50), - an annular row of hollow parts (P2) alternating with the solid parts (P1), each of the hollow parts (P1) comprising a bottom (F) which is connected to the vertices (S) of the two solid parts (P2) between which the hollow part (P1) extends respectively by two concave curved joining edges (B1, B2), each of these joining edges (B1, B2) having a shape in the form of a portion of an ellipse (E). Figure for the abstract: Figure 3

Description

Title of the invention: ANNULAR PART FOR AN AIRCRAFT TURBO-MACHINE Technical field of the invention

[0001] The present invention relates to an annular part for an aircraft turbomachine, as well as to an aircraft turbomachine comprising such a part. Technical background

[0002] An aircraft turbomachine typically comprises from upstream to downstream, with reference to the flow of gases in the turbomachine in operation, a fan or propulsion propeller, at least one compressor, an annular combustion chamber, at least one turbine, and a combustion gas exhaust nozzle.

[0003] The turbine rotor is connected by a shaft to a compressor rotor to form a rotating body.

[0004] In the case of a twin-spool turbojet engine, respectively high pressure and low pressure, the turbojet engine comprises from upstream to downstream a low pressure compressor, a high pressure compressor, the combustion chamber, a high pressure turbine and a low pressure turbine.

[0005] The high pressure body comprises the rotors of the high pressure compressor and the high pressure turbine, and the high pressure shaft connecting these rotors.

[0006] The low pressure body comprises the rotors of the low pressure compressor and the low pressure turbine, and the low pressure shaft connecting these rotors. The low pressure shaft rotates the shaft of the fan or the propeller, either directly or via a mechanical reducer.

[0007] The bodies and the rotors rotate around the same axis which is generally the longitudinal axis of the turbomachine.

[0008] A rotor generally comprises several annular parts which extend around the same axis and which are fixed to each other by clamping.

[0009] A turbine rotor 10 as illustrated in [Fig. 1] comprises for example several rotor discs 12 fixed to each other by annular flanges 20, 22 which extend around an axis X.

[0010] A rotor disk 12 has an annular shape around the axis X and comprises at its external periphery cells 14 for mounting roots 16 of rotor blades 18. Alternatively, the blades 18 could be formed in a single piece with the disk 12.

[0011] The disc 12 comprises upstream a first annular flange 20 which is connected by a first web 24 to the disc 12, and downstream a second annular flange 22 which is connected by a second web 26 to the disc 12. The disc 12, the webs 24, 26 and the flanges 20, 22 are generally formed from a single piece of metal alloy.

[0012] The blades 18 carried by the disc 12 form a rotor blading E1 which is arranged between two stator bladings E2 located respectively upstream and downstream of the rotor blading E1.

[0013] A stator blade E2 comprises an annular row of stator blades 30 whose internal periphery is connected to a sealing ring 32. This ring 32 extends around the axis X, and generally around the flanges 20, 22, and carries an abradable annular coating 34.

[0014] As can be seen in the drawing, an annular flange 36 is located between two adjacent discs 12, and radially inside the stator blading E2.

[0015] The flange 36 comprises annular wipers 38 which extend radially outwards and are intended to cooperate by friction with the abradable coating 34 to form a labyrinth-type seal by baffle effect.

[0016] The flange 36 comprises an internal annular flange 40 which is interposed between the downstream flange 22 of an upstream disc 12 and the upstream flange of a downstream disc 12, and which is fixed to these flanges 20, 22 by fixing elements of the screw or bolt type 42.

[0017] The flange 36 may further comprise annular tabs 44 which bear axially on faces of the disc 12 for the purpose of retaining the roots 16 of the blades 18 with respect to the disc 12.

[0018] In the present application and in the description which follows, an “annular part” designates indifferently a rotor disk 12 or a flange 36 as illustrated in [Fig.l] for example.

[0019] The flange 20, 22, 40 carried by the “annular part” has a general orientation perpendicular to the axis X. It comprises orifices 50 opening axially and capable of receiving the fixing elements (figures 1 and 2).

[0020] As can be seen in [Fig.2], the flange 20, 22, 40 is scalloped and comprises an annular row of solid parts PI which comprise the aforementioned orifices 50, and an annular row of hollow parts P2 alternating with the solid parts PL

[0021] The flange 20, 22, 40 has an internal peripheral contour 52 which is corrugated and which comprises hollows 52a at the hollow parts P2 and bumps 52b at the solid parts PL

[0022] Each of the hollow parts P2 comprises a bottom F which is connected to the vertices S of the two solid parts PI between which the hollow part P2 extends respectively by two concave curved joining edges B1, B2.

[0023] In the current technique, each of these junction edges B1, B2 has a portion of a circle shape ([Fig.2]).

[0024] In operation, the annular parts of a rotor are subjected to extremely high forces, which limits the number of flight cycles of these parts.

[0025] The service life of the parts is limited by the service life of the most stressed areas, which are generally the connection radii in most cases, and more specifically those of the joining edges of the flanges.

[0026] The present invention provides a simple, effective and economical solution to this problem. Summary of the invention

[0027] The invention relates to a part for an aircraft turbomachine, this part having a generally annular shape around an axis and comprising an annular flange which extends around this axis and which has a generally perpendicular orientation relative to this axis, the flange comprising orifices opening axially and capable of receiving fixing elements, the flange being scalloped and comprising an annular row of solid parts which comprise the aforementioned orifices, and an annular row of hollow parts alternating with the solid parts, each of the hollow parts comprising a bottom which is connected to the tops of the two solid parts between which the hollow part extends respectively by two concave curved joining edges, characterized in that each of these joining edges has a shape in the form of a portion of an ellipse.

[0028] The invention thus proposes to replace the shape of the joining edges of the flanges. The inventors have found that a shape in the form of a portion of an ellipse, rather than a portion of a circle, makes it possible to significantly reduce the forces in this area and to increase the service life of the part.

[0029] The part according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another: • said joining edges each have a quarter-elliptical shape; this specific shape is particularly advantageous for the distribution of forces in this area; • the ellipse has a larger dimension that extends tangentially to a circumference centered on the axis, and a smaller dimension that extends radially to the axis; this specific shape is particularly advantageous for the distribution of forces in this area; • a first of said joining edges has a shape in the form of a portion of a first ellipse, and a second of said joining edges has a shape in the form of a portion of a second ellipse, the first and second ellipses having identical dimensions and having centers which are at a distance from each other less than or equal to 20% of a largest dimension of these first and second ellipses; this specific distance is particularly advantageous for the distribution of forces in this zone; • the scalloped flange has an internal peripheral contour which is wavy, the ellipse having a smaller dimension which is greater than an amplitude of this internal peripheral contour; this specific configuration is particularly advantageous for the distribution of forces in this area; • the part being a rotor disc carrying on its external periphery rotor blades or rotor blade mounting cells, or being a rotor flange carrying on its external periphery annular sealing lips; • the flange comprises two radial faces between which the said orifices extend, one of these faces being connected to a cylindrical surface which extends around the axis by a fillet, this fillet extending around the axis and having in axial section a rounded concave shape in a portion of an ellipse; this specific configuration is particularly advantageous for the distribution of forces in this zone; • said connection fillet has a quarter-elliptical shape in axial section; this specific shape is particularly advantageous for the distribution of forces in this area; • the ellipse of the fillet has a larger dimension that extends parallel to the axis, and a smaller dimension that extends radially to the axis; this specific shape is particularly advantageous for the distribution of forces in this area.

[0030] The present invention also relates to an aircraft turbomachine comprising at least one part as described above. Brief description of the figures

[0031] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0032] [Fig-1] [Fig.l] is a partial schematic half-view in axial section of a tur aircraft engine, and in particular a turbomachine turbine,

[0033] [Fig.2] [Fig.2] is a partial schematic view of a flange of an annular part of aircraft turbomachine, such as that of [Fig.l],

[0034] [Fig.3] [Fig.3] is a view similar to that of [Fig.2] and illustrating a flange of an annular part according to the invention, and

[0035] [Fig.4] [Fig.4] is a partial schematic view in axial section of a flange of a annular part according to the invention. Detailed description of the invention

[0036] Figures 1 and 2 have already been described in the above.

[0037] [Fig.l] may illustrate an environment of the present invention and in particular several types of annular parts in accordance with the invention.

[0038] As mentioned above, the “annular part” may be a rotor disk 12 or a flange 36 even if the invention is not limited to these two parts.

[0039] Generally, the part has a general annular shape around an axis X and comprises an annular flange 20, 22, 40 which extends around this axis X and which has a general orientation perpendicular to this axis.

[0040] The flange 20, 22, 40 comprises orifices 50 which open axially and are capable of receiving fixing elements such as screws or bolts 42.

[0041] The flange 20, 22, 40 is scalloped and comprises an annular row of solid parts PI which comprise the aforementioned orifices 50, and an annular row of hollow parts P2 alternating with the solid parts PL

[0042] The flange 20, 22, 40 has an internal peripheral contour 52 which is corrugated and which comprises hollows 52a at the hollow parts P2 and bumps 52b at the solid parts PL

[0043] Each of the hollow parts P2 comprises a bottom F which is connected to the vertices S of the two solid parts PI between which the hollow part PI extends respectively by two concave curved joining edges B1, B2.

[0044] According to the invention, these junction edges B1, B2 have a shape in the form of a portion of an ellipse E as illustrated in [Fig.3].

[0045] The joining edges B1, B2 preferably have a quarter-ellipse shape E as visible in the drawing.

[0046] Advantageously, the ellipse E has a larger dimension Ea which extends tangentially relative to a circumference centered on the X axis, and a smaller dimension Eb which extends radially relative to the X axis.

[0047] In the example shown, a first of the joining edges B1 has a shape in the form of a portion of a first ellipse E1, and a second of the joining edges B2 has a shape in the form of a portion of a second ellipse E2.

[0048] The first and second ellipses El, E2 have identical dimensions Ea, Eb and have centers Cl, C2 which are at a distance D from each other less than or equal to 20% of a largest dimension Ea of these first and second ellipses El, E2.

[0049] Preferably, the ellipse E has a smaller dimension Eb which is greater than an amplitude A of the internal peripheral contour 52.

[0050] [Fig.4] shows an axial sectional view of a flange 20, 22, 40 such as that of the [Fig.3].

[0051] The flange 20, 22, 40 comprises two radial faces 60, 62 between which the orifices 50 extend, one of these faces 60 being connected to a cylindrical surface 64 which extends around the axis X by a connecting fillet 66. This surface 24 can for example be used to cooperate by abutment with flats of the bolts 42 in order to im- rotate in the 50 holes of the flanges.

[0052] The connecting fillet 66 extends around the axis X and has in axial section a rounded concave shape in the form of a portion of an ellipse F.

[0053] Preferably, the connecting fillet 66 has in axial section a quarter-ellipse shape F.

[0054] Advantageously, the ellipse F of the fillet 66 has a larger dimension Fa which extends parallel to the axis X, and a smaller dimension Fb which extends radially to the axis X.

[0055] The invention allows in particular: - to reduce mechanical constraints in areas where they are significant, - to increase the lifespan of parts.

[0056] Since the geometric modifications of the parts are limited, their production process is little impacted and can remain identical.

Claims

Claims

1. Part for an aircraft turbomachine, this part having a generally annular shape around an axis (X) and comprising an annular flange (20, 22, 40) which extends around this axis (X) and which has a generally perpendicular orientation relative to this axis (X), the flange (20, 22, 40) comprising orifices (50) opening axially and capable of receiving fixing elements, the flange (20, 22, 40) being scalloped and comprising an annular row of solid parts (PI) which comprise the aforementioned orifices (50), and an annular row of hollow parts (P2) alternating with the solid parts (PI), each of the hollow parts (PI) comprising a bottom (F) which is connected to the tops (S) of the two solid parts (P2) between which the hollow part (PI) extends respectively by two joining edges (B1, B2) concave curved, characterized in that each of these joining edges (Bl, B2) has a portion of an ellipse (E) shape.

2. Part according to claim 1, in which said joining edges (B1, B2) each have a quarter-ellipse shape (E).

3. A part according to claim 1 or 2, wherein the ellipse (E) has a larger dimension (Ea) which extends tangentially to a circumference centered on the axis (X), and a smaller dimension (Eb) which extends radially to the axis (X).

4. Part according to one of the preceding claims, in which a first of said joining edges (B1) has a shape in the form of a portion of a first ellipse (El), and a second of said joining edges (B2) has a shape in the form of a portion of a second ellipse (E2), the first and second ellipses (El, E2) having identical dimensions and having centers (C21, C2) which are at a distance (D) from each other less than or equal to 20% of a largest dimension (Ea) of these first and second ellipses (El, E2).

5. Part according to one of the preceding claims, in which the scalloped flange (20, 22, 40) has an internal peripheral contour (52) which is wavy, the ellipse (E) having a smallest dimension (Eb) which is greater than an amplitude (A) of this internal peripheral contour (52).

6. Part according to one of the preceding claims, the part being a rotor disc (12) carrying at its external periphery rotor blades (18) or cells (16) for mounting rotor blades (18), or being a rotor flange (26) carrying at its external periphery wipers an- sealing rings (38).

7. Part according to one of the preceding claims, in which the flange (20, 22, 40) comprises two radial faces (60, 62) between which said orifices (50) extend, one of these faces (60) being connected to a cylindrical surface (64) which extends around the axis (X) by a fillet (66), this fillet (66) extending around the axis (X) and having in axial section a rounded concave shape in a portion of an ellipse (F).

8. Part according to claim 7, in which said fillet (66) has in axial section a quarter-ellipse shape (F).

9. A part according to claim 7 or 8, wherein the ellipse (F) of the fillet (66) has a larger dimension (Fa) which extends parallel to the axis (X), and a smaller dimension (Fb) which extends radially to the axis (X).

10. Aircraft turbomachine, comprising at least one part according to one of the preceding claims.

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