Aircraft cabin entrance

Abstract

An air inlet for an aircraft cabin, comprising: a lip skin defining a curved surface of the inlet, the curved surface extending around a longitudinal axis of the inlet; a front bulkhead; an inner barrel having a radially inner surface defining a surface of the inlet, a radially outer surface, and a sound attenuation layer arranged between the radially inner surface and the radially outer surface; and a tie frame fixed to the lip skin and / or the front bulkhead; wherein a first portion of the tie frame extends over at least a portion of the sound attenuation layer of the inner barrel and is fixed to the radially outer surface of the inner barrel.

Description

Technical Field

[0001] The invention relates to an aircraft cabin entrance and to an aircraft cabin incorporating such an entrance. Technical Field

[0003] It is desirable to isolate the sound in one section of an aircraft from other sections of the aircraft and / or the exterior of the aircraft. This is particularly important for aircraft cabins, and especially for their inlets, where the noise generated by the engines and the airflow at the engine air intakes should be suppressed or attenuated to avoid excessive noise pollution.

[0004] Conventional sound attenuation is provided by a sound attenuating layer, which may be a non-structural layer. Known aircraft cabin inlet designs require the joint between the lip skin, forward bulkhead and inner barrel assembly (referred to as the A0 joint) to be formed as two separate joints, the joint between the forward bulkhead and the lip skin being separate from the joint between the lip skin and the inner barrel.

[0005] Known A0 joints have large areas without a sound attenuating layer or a sound attenuating layer of decreasing thickness, which may be referred to as being unacoustically treated, and thus may allow excessive noise to escape from the cabin's air inlet. Summary of the invention

[0006] The present invention can improve the acoustically treatable area between the lip skin and the acoustically treated inner barrel, thereby reducing the amount of noise leaving the cabin.

[0007] According to a first aspect of the present invention, there is provided an aircraft cabin inlet, comprising: a lip skin defining a curved surface of the inlet, the curved surface extending around a longitudinal axis of the inlet; a front bulkhead; an inner barrel having a radially inner surface defining a surface of the inlet, a radially outer surface and a sound attenuation layer arranged between the radially inner surface and the radially outer surface; and a connecting frame fixed to the lip skin and / or the front bulkhead; wherein a first portion of the connecting frame extends over at least a portion of the sound attenuation layer of the inner barrel and is fixed to the radially outer surface of the inner barrel.

[0008] With such an arrangement, the sound attenuation layer of the inner barrel may extend further forward and / or may not taper. Thus, the area that may be acoustically treated may be increased. In particular, providing a link frame extending over at least a portion of the sound attenuation layer of the inner barrel provides a solid mounting point for the acoustically treated inner barrel. This means that the sound attenuation layer between the radial inner and outer surfaces of the inner barrel does not need to taper to create a solid mounting point on the inner barrel, as is typically required using a conventional A0 joint. This increases the acoustically treated area of ​​the inner barrel and may reduce noise pollution.

[0009] Additionally or alternatively, by mounting the forward bulkhead to the inner barrel via a tie frame, the inner barrel and therefore the sound attenuation layer can also be extended forward. This increases the acoustic treatment area of ​​the inner barrel.

[0010] The lip skin and bulkhead may together define a compartment that may be used to provide an anti-icing function for the nacelle's air inlet by allowing hot gases to escape forward of the A0 junction, thereby preventing ice from accumulating on the radially inner surface of the inlet.

[0011] The inner barrel may have an end surface substantially perpendicular to the radial outer surface and / or radial inner surface of the inner barrel. Such an inner barrel with a square end surface can increase the acoustic treatment area of ​​the inner barrel, thereby improving acoustic attenuation, because the thickness of the acoustic attenuation layer may not be tapered.

[0012] The tie frame may also include a second portion, and the second portion of the tie frame may extend above the end surface of the inner barrel, thereby providing a secure connection between the inner barrel and the lip skin, and optionally between the radially outer surface of the inner barrel and the lip skin.

[0013] The tie frame may also include a third portion, and the third portion of the tie frame may extend or overlap at least a portion of the front bulkhead. This arrangement may improve load transfer from the front bulkhead to the inner barrel and may provide a more secure connection.

[0014] The link frame may further include a fourth portion, which is a curved surface of the link frame, referred to herein as a link frame curved surface, arranged to overlap the lip skin. This arrangement may provide a more secure joint between the link frame and the lip skin.

[0015] For example, the linking frame may include the first and fourth portions without necessarily also including the second and / or third portions. Likewise, the linking frame may include the first and third portions without necessarily also including the second portion. The presence of the third or fourth portions does not require the presence of the second or third portions, respectively.

[0016] The lip skin may have a flat surface extending radially outward from a curved surface defined by the lip skin, and at least a portion of the flat surface of the lip skin may overlap the tie frame, optionally overlapping a second portion of the tie frame. With this arrangement, loads may be transferred from the lip skin through the tie frame to the radially outer surface of the inner barrel. This arrangement allows additional acoustic treatment to be applied to the lip skin. Mounting the flat surface of the lip skin to the tie frame may reduce the space between the lip skin and the acoustic treatment area of ​​the inner barrel.

[0017] The first part of the connecting frame can be formed integrally with the second, third and / or fourth parts. Such an arrangement can improve the strength of the connecting frame.

[0018] The lip skin may include a structural sheet defining a lip skin curved surface and a lip skin acoustic attenuation layer arranged on the radially outer side of the structural sheet. With this arrangement, additional sound attenuation may be provided in front of the inner barrel.

[0019] The lip skin may also include an additional structural sheet on the radially outer surface of the lip skin sound attenuation layer, the additional structural sheet being fixed to the tie frame. This arrangement may provide improved lip skin strength and protection for the sound attenuation sheet.

[0020] The aircraft nacelle may also include a second attachment frame coupled to the additional structural sheet and the structural sheet of the lip skin. This arrangement may reduce any likelihood of layer separation on the lip skin. This arrangement may also improve the stress resistance of the lip skin portion including additional acoustic treatment.

[0021] The link frame and / or the second link frame may be annular. The link frame and / or the second link frame may be formed from a plurality of parts, each part being a segment of an annular shape, optionally two semi-annular parts. This may provide an arrangement that is easier to assemble.

[0022] The aircraft nacelle may also include ventilation holes through the skin of the nacelle in front of the tie frame. These may provide an anti-icing function for the inlet.

[0023] The inner cylinder may include a radially inner structural sheet defining a radially inner surface and a radially outer structural sheet defining a radially outer surface, and the sound attenuation layer is arranged between the radially inner structural sheet and the radially outer structural sheet. By such an arrangement, the strength of the inner cylinder can be improved.

[0024] According to a second aspect of the present invention, there is provided a nacelle comprising an air inlet according to any of the above aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0026] Figure 1 An aircraft cabin is shown;

[0027] Figure 2 A cross section of the air inlet of the nacelle is shown;

[0028] Figure 3 A cross section showing a known joint between the lip skin, forward bulkhead and inner barrel;

[0029] Figure 4 shows a cross section of an air inlet according to an embodiment of the present invention;

[0030] Figure 5shows a cross section of an air inlet according to an embodiment of the present invention;

[0031] Figure 6 shows a cross section of an air inlet according to an embodiment of the present invention;

[0032] Figure 7 shows a cross section of an air inlet according to an embodiment of the present invention;

[0033] Figure 8 shows a cross section of an air inlet according to an embodiment of the present invention;

[0034] Fig. 9 shows a cross section of an air inlet according to an embodiment of the present invention;

[0035] Fig.10 A linked frame according to the invention is shown. DETAILED DESCRIPTION

[0036] Figure 1 An aircraft nacelle 10 is shown, the exterior of which is formed by three main parts: an air intake 12 (also referred to as an air inlet 12), a fan housing 14, and a thrust reverser 16. The purpose of the air intake 12, which may be referred to as an inlet cowl, is to direct the airflow into the fan and into the engine and to create an aerodynamically smooth surface for the airflow over the exterior of the aircraft nacelle 10. The airflow entering the inlet cowl 12 generates a large amount of noise, so the inlet cowl 12 should function to attenuate the noise and prevent excessive noise pollution outside the aircraft.

[0037] like Figure 1 As shown, the nacelle may have a longitudinal axis A1 extending through the nacelle. The longitudinal axis A1 may be generally aligned with the intended direction of movement of the nacelle. The term "radial direction" as used herein is defined relative to the longitudinal axis A1, with radially inner regions being closer to the longitudinal axis A1 and radially outer regions being further away from the longitudinal axis A1. The longitudinal axis A1 may also be considered as the longitudinal axis A1 of the air inlet 12.

[0038] Figure 2 A cross section of a portion of the air inlet 12 is shown. The air inlet 12 comprises a lip skin 18 forming an air inlet lip 20 which extends around the periphery of the nacelle and forms the leading edge of the nacelle. The lip skin 18 has a curved surface 22 extending circumferentially around the longitudinal axis A1 of the nacelle, which defines the radial inner surface of the lip 20. In this way, the forwardmost part of the inner surface of the annular inlet of the nacelle is defined by the curved surface 22 of the lip skin 18.

[0039] Figure 2The air inlet 12 also includes an inner barrel 24. The radial inner surface of the inner barrel 24 is aligned with the curved surface 22 of the lip skin 18, so that the curved surface 22 of the lip skin and the radial inner surface 24 of the inner barrel create an aerodynamically smooth surface for the airflow entering the nacelle. In this way, the upstream portion of the inlet to the nacelle is defined by the curved surface 22 of the lip skin 18, and the downstream portion of the inlet to the nacelle is defined by the radial inner surface of the inner barrel 24. At the rear end of the inner barrel 24, the inner barrel 24 is connected to the fan case 14.

[0040] The inner barrel 24 is acoustically treated in that it includes a sound attenuating layer, which may be a honeycomb sheet or a different low-density material, such as a honeycomb foam or sponge. The sound attenuating layer is disposed between the radial inner surface and the outer surface of the inner barrel 24.

[0041] like Figure 2 As shown, the air inlet 12 also includes a forward bulkhead 26 extending across the interior of the air inlet lip 20, so that the lip skin 18 and the forward bulkhead together define a compartment 28. The compartment 28 can contain hot air, or a duct for delivering hot air, and can have vents 19 arranged radially inward of the leading edge of the nacelle 10, which are used to discharge hot air, which in turn can pass through the radial inner surface of the inlet 12 to prevent ice accumulation on the surface of the nacelle.

[0042] Figure 3 A cross section of a known joint between the lip skin 18, the inner barrel 24, and the forward bulkhead 26 of the cabin air inlet 12 is shown in more detail (this area is referred to as the A0 joint). In this design, the forward bulkhead 26 is directly connected to the lip skin 18, and in a separate connection, the lip skin 18 is connected to the inner barrel 24. The lip skin 18 may be connected to the inner barrel 24 via a first web 17a at a thinner portion of the inner barrel 24a, and the forward bulkhead 26 may be connected to the lip skin 18 via a second web 17b. The first web 17a connecting the inner barrel 24 and the lip skin 18 may be mounted above the second web 17b, as shown in FIG. Figure 3 shown.

[0043] like Figure 3 As shown, this requires a tapered portion 24t of the inner barrel 24 for transitioning from a thick portion having a sound attenuating layer to a thinner region 24a. This results in an area that cannot be acoustically treated because the tapered portion 24t may have suboptimal sound attenuation due to having a thinner sound attenuating layer. In addition, the first and second connecting plates 17a, 17b cannot be easily attached to the sound attenuating sheet, which results in an area A that is not acoustically treated.

[0044] The first embodiment of the present invention is Figure 41 is shown in cross section. Here, the lip skin 118 is connected to the inner barrel 124 via a connecting frame 130. The inner barrel 124 has a radially outer surface 124a defined by a radially outer structural sheet 125a and a radially inner surface 124b defined by a radially inner structural sheet 125b. The structural sheets 125a, 125b can each be a composite sheet or a metal sheet, such as aluminum. The sound attenuation sheet 132 can be positioned between the structural sheets 125a and 125b. The radially inner sheet 125b can have holes so that sound waves from the inlet 12 can enter and be absorbed by the sound attenuation sheet 132. For this reason, the radially outer structural sheet 125a can carry greater forces.

[0045] The first portion 130a of the tie frame extends over the radially outer surface 124a of the inner barrel 124 and is fixed to the radially outer surface 124a of the inner barrel 124, in particular the radially outer sheet 125a, so that the first portion 130a extends at least partially over the sound attenuation layer 132, which is positioned between the radially inner sheet 125b and the radially outer sheet 125a of the inner barrel 124. The inner barrel 124 extends behind the tie frame 130.

[0046] The second portion 130b of the link frame 130 extends over a front surface 124c of the inner barrel 124, which front surface 124c (which may also be referred to as an end surface) is an annular surface that is substantially perpendicular to the radially inner and outer surfaces 124a, b.

[0047] The second portion 130b of the tie frame 130 is secured to the lip skin 118, and in particular to the radially extending annular surface 118b of the lip skin 118. The overlapping portions of the tie frame 130 and the lip skin 118 may provide a secure joint between the lip skin 118 and the inner barrel 130.

[0048] and Figure 3 Compared to the known arrangement shown in , the thickness of the sound attenuation layer 132 at the end surface 124c, and therefore the distance between the radially outer sheet 125a and the radially inner sheet 125b at the end surface 124c, can be the same as the thickness of the rest of the inner barrel 124 (i.e., the inner barrel thickness does not taper toward the end surface). As described above, this means that the acoustic attenuation loss toward the end surface 124c can be reduced.

[0049] The second portion 130b of the tie frame 130 may be substantially perpendicular to the first portion 130a and may define a flat surface extending radially outward from the curved surfaces 124a,b of the inner barrel 124. In this embodiment, the forward bulkhead 126 may be secured to the lip skin 118 as in known arrangements.

[0050] exist Figure 5 A second embodiment of the present invention is shown in FIG. Figure 5 1 and 12. A cross section of the connection between the forward bulkhead 126 and the inner barrel 124 via the connecting frame 130 is shown. The first portion 130a of the connecting frame is shown in FIG. Figure 4 The third portion 130c of the tie frame 130 may overlap and be secured to at least a portion 126c of the forward bulkhead 126.

[0051] In this embodiment, the inner barrel 124 may include a tapered portion terminating in a thin portion 124d that may be connected to the lip skin 118 via a web 117b as in known arrangements. However, in this arrangement, the inner barrel 124 may have a substantially constant thickness from the fan case 14 to the forward bulkhead 126 and may therefore provide improved sound attenuation.

[0052] exist Figure 6 A third embodiment of the present invention is shown in FIG. Figure 6 A cross section of an integral A0 joint between the inner barrel 124 , the lip skin 118 , and the forward bulkhead 126 via an integral tie frame 130 is shown. Figure 6 Including the above references Figure 4 and 5 The connection of the lip skin to the inner barrel can be similar to that of the reference Figure 4 The connection between the front bulkhead and the inner barrel can be the same as described in reference Figure 5 Same as described.

[0053] By integrating Figure 5 and 6 In accordance with aspects of both embodiments, greater sound attenuation can be achieved, and the one-piece link frame 130 in which the first, second and third portions 130a, 130b and 130c are all formed as a single piece can provide improved strength and / or reduced weight. The link frame can also include multiple components to facilitate assembly, each component defining a portion of the link frame 130, such as a segment of a ring, each ring segment can include an integrally formed first, second and third portion 130a, 130b, 130c. In this way, the first, second and third portions 130a, 130b, 130c of each link frame 130 can be formed together as a single piece.

[0054] Figure 7A cross section of a fourth embodiment is shown in which an alternative connection is incorporated between the lip skin 118 and the inner barrel 124 via a tie frame 130. Here, the tie frame 130 includes a fourth portion 130d that is arranged to overlap with the portion 118d of the lip skin 118. The fourth portion 130d of the tie frame 130 has a curved surface of the tie frame having a shape that is arranged to extend over the curvature of the lip skin 118. The fourth portion 130d may be substantially parallel to the inner and / or outer surfaces 124a, 124b of the inner barrel 124 and / or the first portion 130a of the tie frame 130. The fourth portion 130d may extend substantially perpendicularly from the second portion 130b. The fourth portion 130d may be connected to the first, second and / or third portions 130a, 130b, 130c in the same manner as described above with respect to Figure 5 and Figure 6 The same method is used to form an integral body.

[0055] Figure 8 Shown with Figure 6 A fifth embodiment is substantially similar to the embodiment of the present invention, which incorporates a lip skin sound attenuation layer 134, which can further reduce the noise escaping from the inlet 12. The lip skin sound attenuation layer 134 can be on the radially outer side of the lip skin 118, which can be a structural sheet. An additional structural sheet 136 can be disposed above the lip skin sound attenuation layer 134. The additional structural sheet 136 can be secured to the tie frame 130 and the lip skin 118 at a location forward of the lip skin sound attenuation sheet 134, as shown in FIG. Figure 8 shown.

[0056] To allow sound waves to enter the lip skin sound attenuation layer 134 , at least a portion of the lip skin 118 may be perforated similar to the radially inner structural sheet 125 b of the inner barrel 124 , and the majority of the lip skin's structural strength may be provided by additional structural sheets 136 .

[0057] Fig. 9 A cross section of a sixth embodiment is shown. Fig. 9In the embodiment of the present invention, the lip skin provides an acoustic treatment section 134, which includes a radially inner structural sheet 134a, a radially outer structural sheet 134b and a sound attenuation layer 135 between the radially inner structural sheet 134a and the radially outer structural sheet 134b. The inner structural sheet 134a may have a number of holes to allow sound waves to enter the lip skin sound attenuation sheet 135 and be absorbed thereby. The fourth portion 130d of the tie frame 130 overlaps and is fixed to the radially outer structural sheet 134b, which extends above the lip skin sound attenuation layer 135. In this arrangement, the second portion 130b of the tie frame 130 only partially extends above the end surface 124c of the inner barrel 124 (the second portion 130b may be otherwise the same as described in the previous embodiment).

[0058] The second connecting frame 138 connects the additional acoustic treatment segment 134 to the lip skin 118. The first portion 138a of the second connecting frame 138 can overlap the radially outer portion of the acoustic treatment segment so that it extends above the sound attenuation sheet 135 and is secured to the radially outer structural sheet 134b. The second portion 138b of the second connecting frame 138 can overlap a portion of the lip skin 118 and thereby be secured to the lip skin 118. The third portion 138c of the second connecting frame 138 can extend above the end surface 134c of the acoustic treatment segment 134. Fig. 9 As shown, the second tie frame 138 is positioned at the forward end of the acoustic treatment section 134 , opposite the end adjacent the inner barrel 134 .

[0059] Fig.10 A link frame 130 is shown. Although the link frame 130 shown corresponds to Figure 7 , but the concepts apply to any of the embodiments discussed above and to Fig. 9 The second link frame 138. The link frame 130 is a substantially circular component that may be a single piece or may be formed from multiple pieces, such as two annular portions 142a, 142b that may be connected via shorter connecting pieces 144a, 144b.

[0060] The tie frame described in any of the above embodiments has the advantage of improving the load transfer between the inner barrel and the lip skin and / or the forward bulkhead. In any of the above embodiments, the connection between the tie frame 130 and any other element of the nacelle can be by means of mechanical fasteners and / or splice plates, or using any other method known to those skilled in the art, such as welding or adhesive bonding.

[0061] It should be noted that the above embodiments illustrate rather than limit the present invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the present invention as defined by the appended claims. In the claims, any figure marks placed in brackets should not be understood as limiting the claims. The word "comprise" does not exclude the presence of components or steps other than those listed in any claim or specification as a whole. The singular reference to a component does not exclude the plural reference to these components, and vice versa. The various components of the present invention may be implemented by means of hardware comprising several different elements. In a device claim that lists several components, several of these components may be implemented by one or the same hardware. The fact that specific measures are described in mutually different dependent claims does not mean that a combination of these measures cannot be used to produce good results.

Claims

1. An air inlet for an aircraft cabin, comprising: a lip skin (118) defining a curved surface of the inlet, the curved surface extending about a longitudinal axis of the inlet; forward bulkhead (126); an inner cylinder (124) having a radially inner surface (124b) defining a surface of the inlet, a radially outer surface (124a), and a sound attenuation layer (132) disposed between the radially inner surface and the radially outer surface; and a connecting frame (130) secured to the lip skin and the forward bulkhead; wherein a first portion (130a) of the link frame extends over at least a portion of the sound attenuation layer of the inner barrel and is secured to the radially outer surface (124a) of the inner barrel, and wherein the second portion (130b) of the link frame is substantially perpendicular to the first portion and defines a flat surface extending above the end surface of the inner barrel, The connecting frame (130) further comprises a third portion (130c), the third portion extending above at least a portion (126c) of the front bulkhead (126), and wherein the third portion (130c) extends from the first portion (130a) and the second portion (130b), wherein the connecting frame (130) is Y-shaped as shown in cross section, and the first, second and third portions of the connecting frame respectively constitute three different legs of the Y-shape.

2. The air inlet according to claim 1, characterized in that The inner cylinder has an end surface that is substantially perpendicular to the radially outer surface and / or the radially inner surface.

3. The air inlet according to claim 1, characterized in that The tie frame also includes a fourth portion that is a tie frame curved surface extending over at least a portion of the lip skin.

4. The air inlet according to claim 3, characterized in that The first portion of the link frame is integrally formed with the second portion, the third portion and / or the fourth portion.

5. The air inlet according to claim 4, characterized in that The lip skin has a flat surface extending radially outward from the curved surface, and at least a portion of the flat surface of the lip skin overlaps the tie frame.

6. The air inlet according to claim 5, characterized in that The lip skin and the bulkhead together define a compartment.

7. The air inlet according to claim 6, characterized in that The lip skin includes a structural sheet defining the curved surface and a lip skin sound attenuation layer disposed on a radially outer side of the structural sheet.

8. The air inlet according to claim 7, characterized in that The lip skin further comprises a further structural sheet on a radially outer surface of the lip skin sound attenuating layer, the further structural sheet being secured to the tie frame.

9. The air inlet according to claim 8, characterized in that Also included is a second tie frame coupled to the additional structural sheet and the structural sheet of the lip skin.

10. The air inlet according to claim 9, characterized in that The link frame and / or the second link frame are annular.

11. The air inlet according to claim 10, characterized in that The link frame and / or the second link frame are formed from a plurality of parts, each part being a segment of an annular shape.

12. The air inlet according to claim 11, characterized in that The connecting frame and / or the second connecting frame are formed by two semi-annular parts.

13. The air inlet according to claim 1, characterized in that Also included is a vent through the lip skin, the vent disposed forward of the tie frame and configured to exhaust hot gas to heat a radially inner surface of the inlet.

14. The air inlet according to claim 1, characterized in that The inner cylinder includes a radially inner structural sheet defining the radially inner surface and a radially outer structural sheet defining the radially outer surface, and the sound attenuation layer is disposed between the radially inner structural sheet and the radially outer structural sheet.

15. An aircraft cabin comprising an air inlet according to any one of claims 1 to 14.

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