Method for manufacturing a structural and/or acoustic panel for a nacelle of an aircraft propulsion unit, and corresponding device

Abstract

A method and a device for manufacturing a structural and/or acoustic panel for a nacelle of an aircraft propulsion assembly involves heating, by producing electromagnetic radiation, at least one skin of the structural and/or acoustic panel in such a way as to assemble this skin with a cellular structure of the structural and/or acoustic panel, by diffusion brazing or welding. This heating device can also be used to shape the skin to the cellular structure prior to assembly.

Claims

1. A method for manufacturing a structural and/or acoustic panel for a nacelle of an aircraft propulsion unit, the structural and/or acoustic panel comprising two metallic skins and a metallic cellular structure, the method comprising an arrangement of one of the two metallic skins, called a working skin, such that the working skin delimits a first volume and a second volume of an enclosure, and an arrangement of the metallic cellular structure within the second volume of the enclosure, wherein the method further comprises: placing the working skin, which is not deformed at all, by pinching between pinch areas of the enclosure; applying a gas pressure in the first volume of the enclosure so as to press and hold the working skin against the metallic cellular structure; deforming the working skin in the enclosure by heating the working skin with electromagnetic radiation when the first volume of the enclosure is pressurized by a gas such that the working skin is deformed into a shape conforming to a shape of the metallic cellular structure, the heating by the electromagnetic radiation during the deforming being carried out by selectively heating the working skin from ends up to a center of the working skin so as to uniformize deformation of the working skin; and heating the working skin by infrared electromagnetic radiation by a first heating device placed in the first volume of the enclosure so as to assemble the working skin to the metallic cellular structure by at least one of brazing and diffusion-welding.

2. The method according to claim 1, further comprising a vacuuming of at least one of the first volume and the second volume of the enclosure using a pump.

3. The method according to claim 1, further comprising providing infrared electromagnetic radiation by a second heating device to a tooling on which the other of the two metallic skins is disposed.

4. The method according to claim 3, further comprising placing the second heating device in the second volume of the enclosure.

Description

DRAWINGS

(1) In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

(2) FIG. 1 is a schematic view of a nacelle of an aircraft turbojet engine to which the teachings of the present disclosure are applied;

(3) FIG. 2 illustrates an ejection nozzle of an ejection conduit of a nacelle of an aircraft turbojet engine to which the teachings of the present disclosure are applied;

(4) FIG. 3 illustrates an inner fixed structure of a nacelle of an aircraft turbojet engine, in the form of two half-barrels with their 12 o'clock and 6 o'clock islands to which the teachings of the present disclosure are applied;

(5) FIGS. 4 to 7 illustrate devices according to the present disclosure adapted for the manufacture of panels with different shapes; and

(6) FIG. 8 illustrates a heater implemented in a device according to the present disclosure.

(7) The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

(8) The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

(9) The present disclosure relates to a method and a device for manufacturing a structural and/or acoustic panel for a nacelle of an aircraft propulsion unit.

(10) An example of a nacelle 9 is illustrated in FIG. 1. This nacelle 9 hangs from a pylon 8 intended to be fastened to a wing (not represented) of an aircraft (not represented). The nacelle 9 comprises an upstream section 71 provided with a lip 70 forming an air inlet 99, a middle section 72 receiving a fan (not represented) of a bypass turbojet engine (not represented), and a downstream section 73.

(11) The downstream section 73 includes an inner fixed structure 93 surrounding an upstream portion of the turbojet engine (not represented) and an outer fixed structure 94. The inner fixed structure 93 and the outer fixed structure 94 delimit an annular flow path defining a passage for a main air flow penetrating into the nacelle 9 at the level of the air inlet 99.

(12) The nacelle 9 comprises an ejection conduit including an ejection plug 91 and an ejection nozzle 92. The ejection nozzle 92 is represented in FIG. 2. The ejection plug 91 and the ejection nozzle 92 of the ejection conduit define a passage for a hot air flow coming out of the turbojet engine (not represented).

(13) FIG. 3 shows two parts 931 and 932 of the inner fixed structure 93. The two parts 931 and 932 have a half-barrel like shape so that, once assembled, they confer to the inner fixed structure 93 a barrel like shape.

(14) The inner fixed structure 93 also comprises parts 933, 934, 935, 936 to provide a structural linkage between the inner fixed structure 93 and the outer fixed structure 94. The parts 933 and 934 constitute a so-called 12 o'clock island placed vertically above the barrel. The parts 935 and 936 constitute a so-called 6 o'clock island placed vertically below the barrel.

(15) The present disclosure covers the manufacture of structural and/or acoustic panels in particular for an ejection nozzle 92 of an ejection conduit as illustrated in FIG. 2, for an inner fixed structure 93 as illustrated in FIG. 3, or for any other part of the nacelle 9.

(16) An acoustic panel 1 is illustrated in particular in FIG. 4 which shows a device according to the present disclosure. The acoustic panel 1 comprises two metallic skins 11 and 12 and a honeycomb-type metallic cellular structure 13. As a non-limiting example, the elements 11, 12 and 13 may be made of the same material such as titanium. Alternatively, the elements 11, 12 and 13 may be made of different materials: for example, the elements 11 and 12 may be made of a first metallic material and the element 13 may be made of a second metallic material; or else, the elements 11, 12 and 13 may be made respectively of a first, a second and a third material.

(17) The examples of FIGS. 4 to 7 illustrate a simultaneous assembly of the elements 11, 12 and 13. Nonetheless, the present disclosure allows assembling these elements separately, for example only the elements 11 and 13.

(18) The device according to the present disclosure comprises an enclosure 20 adapted to receive at least one of the two skins, called the working skin 11, so that the working skin 11 delimits a first volume 20A and a second volume 20B of the enclosure 20. This delimitation may be achieved by pinching the working skin 11 between pinch areas (not represented) of the enclosure 20.

(19) Furthermore, the enclosure 20 is adapted to receive the cellular structure 13 within the second volume 20B. In the examples of FIGS. 4 to 6, the second volume 20B of the enclosure 20 receives both the cellular structure 13 as well as the skin 12.

(20) The device according to the present disclosure comprises a heating device 3 represented separately in FIG. 8. The heating device 3 is arranged so as to produce an electromagnetic radiation 31 which may be an infrared radiation, a laser radiation, or other.

(21) Referring to FIG. 4, the heating device 3 comprises a heater 3a arranged so as to heat the working skin 11 by electromagnetic radiation so as to assemble the working skin 11 and the cellular structure 13 by brazing or diffusion-welding during an assembly step. For this purpose, the heater 3a is placed in the first volume 20A of the enclosure 20. In other words, the method according to the present disclosure comprises such an assembly step during which the working skin 11 is heated by electromagnetic radiation 31 so as to assemble the working skin 11 and the cellular structure 13 by brazing or diffusion-welding.

(22) In this example, the heating device 3 also comprises a heater 3b. During the assembly step, a tooling 21 on which the skin 12 is resting, is also heated by electromagnetic radiation 31, using the heater 3b. This allows improving the assembly of the panel and in particular of the skin 12 with the cellular structure 13. Nonetheless, heating of the tooling 21 is optional.

(23) In one form, the first volume 20A of the enclosure 20 is placed under gaseous pressure so as to press and hold the working skin 11 against the cellular structure 13 and where appropriate the cellular structure 13 against the skin 12.

(24) In this example, the skin 12 is made permeable to air for example using piercings (not represented). Hence, vacuuming is also obtained within the cellular structure 13.

(25) In the example of FIG. 4, the elements 11, 12 and 13 are planar and form, after assembly, a planar panel.

(26) It arises from the examples of FIGS. 2 and 3 that some parts of the nacelle 9 have non-planar and/or relatively complex shaped surfaces. Hence, the acoustic panels equipping or forming such parts should have such non-planar and/or relatively complex shaped surfaces which may include completing the forming of a skin before the assembly thereof with the preformed cellular structure.

(27) FIGS. 5 to 7 show devices comprising non-planar elements that are to be assembled to which reference is made in the following.

(28) According to the present disclosure, a forming step may be carried out before the assembly step. During this forming step, the working skin 11 is heated by electromagnetic radiation 31, in the example of FIGS. 5 to 7 using the heater 3a, so as to conform the working skin 11 to the cellular structure 13. During this forming step, the first volume 20A of the enclosure 20 is placed under gaseous pressure, which allows pushing the working skin 11 against the cellular structure 13. When the skin 12 is present, this also allows better pressing the skin 12 on the tooling 21 throughout the cellular structure 13 and the working skin 11.

(29) Hence, the working skin 11 is in one form a solid skin, that is to say airtight, so as to enable a differential pressurization of the first volume 20A and of the second volume 20B of the enclosure 20.

(30) In a form that is compatible with the different variations illustrated in FIGS. 4 to 7, the heating by electromagnetic radiation during the forming step is carried out by selective heating of the working skin 11 from ends up to a center of this working skin 11, so as to uniformize its deformation during the forming step.

(31) In the example of FIG. 6, the acoustic panel 1 corresponds to half of the inner fixed structure as illustrated in FIG. 3, for example that comprising the part 931 (the half barrel) and the two parts 933 and 935.

(32) In order to inhibit the oxidation of the elements to be assembled and provide contact between these elements, the second volume 20B of the enclosure 20 may be vacuumed using a pump during the thermal cycle.

(33) The first volume 20A of the enclosure 20 may also be vacuumed using a pump during the thermal cycle, in the forms that do not involve placing this first volume 20A under gaseous pressure. In the variations in which the first volume 20A is placed under gaseous pressure, the first volume 20A may also be vacuumed using a pump before placing it under gaseous pressure.

(34) As a non-limiting example, with reference to FIGS. 4 to 6, an inert gas pressure is applied in the first volume 20A and therefore on the working skin 11 as soon as the temperature reaches 800? C. and is maintained until the end of the thermal cycle. Optionally, the pressure may be reduced after solidification of the brazed joint.

(35) FIG. 7 illustrates the case of an enclosure 20 arranged so as to assemble an acoustic panel 1a in the form of a rotationally symmetrical part, this acoustic panel 1a comprising the working skin 11, the cellular structure 13 and the skin 12. For example, the acoustic panel 1a manufactured according to the present disclosure may include an ejection nozzle 92 as illustrated in FIG. 2.

(36) Unlike the forms of FIGS. 4 to 6, the enclosure 20 is delimited by the tooling 21 and by walls 22, this enclosure 20, itself, may be placed into a chamber 29 receiving a heater 3b for the heating of the tooling 21.

(37) Of course, the present disclosure is not limited to the examples that have just been described and numerous arrangements may be brought to these examples yet without departing from the scope of the present disclosure. For example, the present disclosure also allows manufacturing structural panels that are not intended for an acoustic treatment function.

(38) Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word about or approximately in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

(39) As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean at least one of A, at least one of B, and at least one of C.

(40) The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.