CN116654240A - Cabin door of aircraft auxiliary power cabin - Google Patents

Abstract

A door for an auxiliary power compartment of a civil aircraft, comprising: a door body made of composite board; a sealing structure disposed along the junction of the door bodies; a lock assembly disposed at the door body; a hinge assembly for hinging the door body to the door frame; the liquid discharging components are arranged in the door bodies; the liquid draining interface is arranged at the door body and used for the cavity-separating system, wherein the sealing structure is arranged at the joint of the door body in a segmented mode and comprises at least two sealing units which are independent from each other and are connected through a baffle, and each sealing unit comprises a sealing piece, a first sealing pressing strip and a second sealing pressing strip. The segmented seal configuration enables better adaptation of the structure of the junction of the door body, avoiding the lock assembly, making the seal configuration easy to install, reducing overall weight, improving sealing effect, and avoiding affecting the aerodynamic profile of the door. The invention also proposes a civil aircraft comprising an auxiliary power pod and the aforementioned pod door for the auxiliary power pod.

Description

Cabin door of aircraft auxiliary power cabin

Technical Field

The present invention relates to a door suitable for a cabin of an auxiliary power (hereinafter referred to as "APU") of a civil aircraft, and to a civil aircraft comprising a door of such an auxiliary power cabin of an aircraft.

Background

The existing large civil aircraft are all provided with an APU system. The APU system is used to power the aircraft's climate control system and engine restart. Since the APU system may be in fire during operation of the aircraft, a fire protection structure such as APU doors needs to be arranged to envelope the APU system to avoid damage to the rest of the fuselage caused by flames in the APU cabin. The door of the APU cabin has fireproof requirement capable of withstanding high temperature of more than 1000 ℃ for 15 minutes.

In addition, the APU cabin may contain fuel, oil, water, and other liquids due to factors such as system pipeline breakage and operating temperature differences. In order to reduce the risk of corrosion, and in order to avoid fires of flammable liquids, it is necessary to drain the liquid in the cabin timely and effectively.

Further, to avoid combustible liquids entering the aircraft tail pipe after removal from the cabin and to avoid liquids outside the aircraft entering the APU cabin, it is also necessary to design specific liquid vents for the APU cabin and to isolate the liquids outside the cabin in areas other than these areas.

Existing APU hatches fall into three categories: the metal structure cabin door, the transverse longitudinal beam layout composite cabin door and the honeycomb sandwich composite structure cabin door. The weight of the metal structure cabin door is large, and the specific strength is poor. The composite hatch door structure with the transverse and longitudinal beam layout has higher height, but has limited weight reduction. The cabin door with the honeycomb sandwich composite material structure has the advantages of light weight, good specific strength and smaller internal occupied space. For example, CN105966631a (publication date: 28, 9) discloses a composite lay-up configuration for APU doors, but it does not take advantage of the light weight, compact structure, small space occupation of the honeycomb sandwich structure, and does not improve the door drainage and/or fire resistance.

From CN216186086U (publication date: 2022, 4, 5) a box firewall for APUs is known, in which a double-leaf, split APU door is described, made of a flame-retardant composite material, having a double-leaf, split structure and sealed with a surrounding firewall. However, in this firewall, a tongue-like seal is used, and the single side is fixed to the structure by a fastener to overlap the composite door body, so that the structure has the following drawbacks: 1. if an integrated sealing piece is adopted, the size of one circle of the APU cabin door is longer, the manufacturing cost and the installation cost of the sealing piece are higher, the appearance of the supporting structure is also required, otherwise, the problem of wrinkles and poor fitting degree can occur when the sealing piece is installed, and the sealing effect is affected; 2. if a split type sealing piece is adopted, the periphery of the sealing piece is not provided with a reinforcing structure, gaps or overlapping can occur in a splicing area of the sealing piece and an overlapping area of the sealing piece and the structure, and the problems of poor fireproof and liquid-tight capacity are caused; 3. when the sealing structure faces fireproof problems, the requirement on shape maintenance capability is high, the sealing piece in the APU cabin door can be directly exposed to flame, and the sealing piece is directly lapped on the composite board, even though the flame-retardant composite material is cured at the temperature of only 180 ℃, the composite board can deform and warp once the field temperature is higher than the temperature, and resin in the composite board can be cracked when the field temperature is higher than 600 ℃, so that the composite board is layered and damaged, and therefore, the fireproof performance of the firewall has hidden danger.

The applicant has proposed a rectifying drain cover outside the machine body in CN206202705U (publication date: 2017, 5, 31), for realizing the drain function of APU system, and particularly meeting the requirement of the drain condition in the flying state. The device is arranged at the pneumatic outer surface of the APU cabin door, and two chambers are arranged in the device and are independent and sealed, so that liquid discharged by the system can be prevented from contacting the high-temperature region of the tail cone or entering the tail spraying region. Meanwhile, the wing-shaped appearance can reduce wind resistance. The applicant has proposed in conjunction therewith an aircraft bleed blocking device in CN206202703U (publication date: 2017, 5, 31), and a fire protection device for the APU tail jet of an aircraft in CN215245556U (publication date: 2021, 12, 21) to further ensure that combustible liquids in the rest of the aircraft (such as APU cabin bleed, rear fuselage front side liquid leak) do not enter the tail jet region, except for system bleed.

However, the fairing disclosed in CN206202705U needs to be used in combination with a seal having a split-cavity structure like that disclosed in US2015337993A1 (publication date: 2015, 11, 26) to achieve APU system drainage, i.e., to enable system combustible liquid to be discharged from the APU cabin and not into the aircraft tail jet area. If the APU cabin door provided with the fairing is not provided with a cavity-separating interface, even if the fairing is arranged on the cabin door, the system liquid can not be discharged in a partitioning way, and if the APU cabin door is not provided with a liquid discharging interface, the sealing piece can not be attached to the structure, so that the sealing is invalid.

Accordingly, there remains a desire in the art to provide a door for an auxiliary power pod of a civil aircraft having at least one of improved fire protection, drainage and sealing capabilities from the standpoint of structural weight saving and manufacturing and installation costs.

Disclosure of Invention

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a door for an auxiliary power compartment having at least improved fire resistance, drainage and sealing capabilities.

The above object is achieved by a door of an auxiliary power pod of a civil aircraft according to the invention comprising: the door body is constructed as a composite material and a honeycomb co-curing sandwich layer, and is preferably two door bodies respectively arranged on the left side and the right side; a sealing structure arranged along the joint of the door bodies; a lock assembly disposed at each door body; a hinge assembly for hinging each door body to the door frame; a liquid discharging assembly arranged in each door body and used for guiding and discharging liquid from the auxiliary power cabin to the outside of the cabin; and a drain port for a split-chamber system provided at least one door body, wherein a sealing structure is provided in sections at the junction of the door bodies, wherein the sealing structure comprises at least two sealing units independent of each other, each sealing unit being connected by a baffle, and wherein each sealing unit comprises a seal, a first sealing bead and a second sealing bead.

Therefore, the cabin door of the auxiliary power cabin of the civil aircraft realizes the sealing of the joint of the door bodies of the cabin door by means of the sealing structure arranged in a sectionalized way, and compared with the arrangement of the continuous sealing structure in the prior art, the sealing structure with the sectionalized structure can be better adapted to the structure of the joint of the door bodies, and avoids various structures arranged at the door bodies, such as a lock assembly, so that the sealing structure is convenient to install, and the total weight is reduced. Compared with the arrangement of dividing only a single sealing element entity into a plurality of sections, the sealing unit structure of the sealing structure improves the sealing effect through the mutual matching of the first sealing pressing strip, the second sealing pressing strip and the sealing element, and avoids the influence of the installation of the sealing structure on the aerodynamic appearance of the cabin door.

In particular, with the seal structure of the sectional type construction, by appropriately adjusting the number of individual seal units, it is possible to minimize the manufacturing cost of the seal structure while ensuring the sealing effect, while helping to reduce the manufacturing cost of the cabin door of the entire auxiliary power cabin.

In one non-limiting embodiment, the first sealing bead and the second sealing bead are asymmetric. In other words, the first sealing bead and the second sealing bead have different and asymmetric shapes after being respectively mounted to the door body. The arrangement is such that a better sealing effect can be produced by the compression between the door bodies when the cabin door is closed

In a preferred embodiment of the invention, the seal is arranged such that its direction of resilience is perpendicular to the opening direction of the hatch. The butt joint step difference between the bodies is not generated even under the condition that the compression amount of the sealing piece is large, so that the door bodies are aligned as much as possible at the joint, and obvious protrusion and recess of the door bodies relative to the whole aerodynamic profile surface due to the butt joint step difference are avoided, and the whole aerodynamic performance is further influenced.

Preferably, in one sealing unit, the seal is fixed at the first sealing bead and a first portion of the first sealing bead fixed at the first door body extends freely over a first portion of the second sealing bead fixed at the second door body.

Preferably, the first portion of the first sealing bead extends obliquely upward relative to the first portion of the second sealing bead. Here, a gap is formed between the first part of the first sealing bead and the first part of the second sealing bead, through which gap the seal can be contacted. The first and second sealing beads are arranged such that, when the hatch is closed, the gap is closed due to the compression deformation of the first portions of the first and second sealing beads, thereby closing the passage of liquid into the space in which the seal is arranged, preventing corrosion of the seal by the liquid.

In another embodiment of the invention, a reinforcement, for example a metal edge seal, is provided at the edge of the door body. By metal edge sealing the door body made of the composite sheet, it is possible to make the door body in the case of high temperature, for example, 600 ℃ or above, or in the case of fire, to avoid deformation, warpage, reduction or even reduction of rigidity of the composite sheet due to cracking failure of the adhesive used in the composite sheet at high temperature.

In another embodiment of the invention, a lock assembly provided at a door of an auxiliary power compartment is used for locking each door body, comprising a first lock abutment, a second lock abutment and a fire protection cover, wherein the fire protection cover is locally arranged to cover the lock abutments from outside. The fire-proof cover is made of a fire-proof metal material, and by arranging the fire-proof cover in a cladding arrangement outside the lock support, parts made of a material which does not prevent fire, such as a light material, can be arranged in the first and second lock supports, thereby contributing to the light weight of the lock assembly and thus to the light weight of the overall structure of the door of the auxiliary power compartment.

Preferably, the second lock abutment engages with a second sealing bead of a sealing unit of the sealing arrangement arranged thereabout, and an elongated flange is provided at the location where the closure abutment engages with the second sealing bead. The provision of the elongated flange further prevents liquid from the auxiliary power compartment from escaping into the enclosed area of the sealing unit of the sealing structure surrounded by the seal, the first seal bead and the second seal bead. Such a construction makes it possible to avoid the accumulation of combustible liquid in the structural gaps of the door of the auxiliary power compartment, which would increase the risk of corrosion and fire.

In yet another embodiment of the invention, a drain assembly for a hatch of an auxiliary power pod includes a drain and a receptacle. The receiving portion is provided at the intersection of the doors and the liquid discharge port is provided at the lowest of the doors, wherein the receiving portion on one door is in fluid communication with the liquid discharge port, so that liquid from the auxiliary power compartment is collected in the receiving portion and directed to the liquid discharge port and discharged out of the auxiliary power compartment via the liquid discharge port, thereby achieving the liquid discharge capability of the door of the auxiliary power compartment according to the present invention.

Optionally, the receptacle is configured as a continuous groove provided at a lower portion of each door for collecting liquid from within the auxiliary power compartment.

Preferably, in order to enhance the liquid collecting ability of the liquid discharge port and to enhance its deformation resistance, the liquid discharge assembly further comprises a reinforcing member provided at the liquid discharge port. The reinforcement may be made of metal and formed to include a recess. The reinforcement, at the door body mounted to the door, contributes to the resistance to deformation that may occur at the lowest point of the door body provided with the liquid discharge port when the door body is subjected to a load, so as to avoid that the liquid discharge port affects its liquid passing capacity due to deformation, for example, the cross section through which the liquid can flow becomes narrower. The concave part of the reinforcement is also provided with a through hole which is respectively aligned with the liquid outlet arranged on the door body.

Optionally, on the other side of the door, i.e. opposite to the side where the reinforcement is provided, a drain is provided, one end of which is in fluid communication with the drain, and the other end of which is connected to a further pipe for guiding the flow of liquid from the drain therethrough and further out of the auxiliary power compartment. Such an arrangement makes it possible to prevent liquid from outside the auxiliary power compartment from flowing back into the auxiliary power compartment through the liquid discharge port accidentally. In one non-limiting embodiment, the drain is configured as a cylinder having two ends of different diameters, with the larger diameter end being in fluid communication with the drain and the smaller diameter end being connected to a further tube.

In yet another embodiment of the invention, the hinge assembly for hingedly connecting the door body to the door frame includes a plurality of hinge arms, such as configured as gooseneck hinges. Of the plurality of gooseneck hinges, only one of the gooseneck hinges is constrained in translational freedom in the axial direction for each door body. The arrangement can avoid the stress in the hinge assembly caused by over constraint when the door body is installed, and is convenient for adjusting the position of the door relative to the door frame, thereby simplifying the installation of the door body.

In a further embodiment of the invention, a drain port for a cavity-divided drain system is provided in at least one of the door bodies of the hatch. The liquid discharge interface is the only part of the proposed cabin door which is not sealed and isolated from liquid except the liquid discharge port of the liquid discharge assembly. The drain port is preferably made of a fire-resistant material and is provided with a plurality of openings that are not mutually penetrated. The liquid discharge fairing of the cavity-separating system is matched with the liquid discharge fairing of the cavity-separating system at the outer side of the cabin door through the cabin door wall plate.

Therefore, the cabin door of the auxiliary power cabin adopts a composite material, titanium/steel and other fireproof metal materials, wherein each door body of the cabin door adopts a honeycomb sandwich co-curing structure, and the cabin door has the advantages of high strength-weight ratio, compact structure and small occupied space. The interfaces such as the sectional sealing structure, the fireproof reinforcing structure and the liquid discharge interface adopted by the cabin door can effectively ensure the fireproof performance of the cabin door and the liquid sealing and isolating capacity except the liquid discharge interface while reducing the manufacturing and mounting cost of the cabin door, and the structure arrangement is more flexible and the mounting and debugging are easier.

The invention furthermore proposes a civil aircraft comprising an auxiliary power pod (APU) and a door according to any of the above-mentioned solutions for the auxiliary power pod.

Drawings

The above features and other features of the invention will be further explained below in connection with embodiments shown in the drawings. The drawings are to be regarded as illustrative in nature and not as restrictive. The drawings show:

figure 1 shows in perspective view an APU door according to an embodiment of the present invention;

fig. 2A shows a partial schematic view of the door body of the APU door;

FIG. 2B shows a cross-section taken along line A-A in FIG. 2A;

fig. 3A shows the sealing structure of the APU door in a perspective view;

FIG. 3B shows a cross-section taken along line B-B in FIG. 3A;

fig. 4 shows in perspective view the lock assembly with the partial fire shield of the APU door;

FIG. 5 shows the lock assembly with a partial fire shield in a perspective view from another angle;

FIG. 6 shows in perspective view the lock assembly of the APU door and a partial sealing arrangement;

FIG. 7 illustrates a single gooseneck hinge in a hinge assembly in a perspective view;

FIG. 8 shows the liquid discharge path of the APU door in perspective view;

FIG. 9 shows in perspective view the stiffener provided at the drain port of the APU door;

fig. 10 shows in perspective view a tube for draining liquid arranged outside the AUP hatch; and figure 11 shows the chambered system drain interface of the APU door.

List of reference numerals:

1L and 1R door body

1b (door body) reinforcing structure

2. Sealing structure

2a seal

2b first sealing bead

2b1 first portion (of first sealing bead)

2b2 second portion (of first sealing bead)

2b3 third part (of first sealing bead)

2c second sealing bead

2c1 first portion (of second sealing bead)

2c2 second portion (of second sealing bead)

2c3 third portion (of second sealing bead)

2d barrier strip

2e flanging

2f (sealing Structure) sealing Unit

3. Lock assembly

3a first Lock support

3b fireproof cover

3c second lock support

4. Hinge assembly

41. Gooseneck hinge

5. Liquid draining assembly

5a stiffener

5a1, 5a2 through holes

5a3, 5a4 recess

5b1, 5b2 liquid discharge tube

5c1, 5c2 pipe fitting

5L and 5R liquid drain

6. Liquid discharge interface

7. Fuselage seal structure

D APU hatch.

Detailed Description

Reference will now be made in detail to the various embodiments of the invention, examples of which are illustrated in the accompanying drawings and described below. While the present invention will be described in conjunction with the exemplary embodiments shown in the drawings, those skilled in the art will recognize that the present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

For convenience in explanation and accurate definition in the appended claims, the terms "upper", "lower", "inner" and "outer" are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

Fig. 1 shows the structure of an APU door of a civil aircraft, generally given the reference D.

As shown in fig. 1 to 2B, APU door D mainly comprises door bodies 1L, 1R located on both sides, which are made of honeycomb sandwich composite material; a seal structure 2 provided in sections along the joint of the door body 1L and the door body 1R; a lock assembly 3; a hinge assembly 4; the drain assembly 5 of APU door D and the drain port 6 of the chambered system.

As for the door bodies 1L, 1R, taking the door body 1L as an example, as seen in fig. 2A and 2B, in the edge region of the door body 1L made of composite material, a reinforcing structure 1B made of fire-resistant metal resistant to high temperature is provided. The reinforcing structure 1b is fixedly connected to the composite plate of which the door body 1L is made by means of a fastener not shown. The provision of the reinforcing structure 1b makes it possible to avoid or at least slow down the delamination of the composite material of the door body 1L of the APU door D, which is produced by the cracking of the resin at high temperature, and thus the buckling deformation, and eventually the reduction, even loss, of the rigidity of the door body 1L, at high temperatures above 600 ℃ even in the event of, for example, a fire.

In particular, in the embodiment shown, when the APU door D is in the closed condition, the edge region of the door body 1L made of composite sheet material provided with the reinforcing structure 1B is engaged with the fuselage sealing structure 7, the fuselage sealing structure 7 being shown in broken lines in fig. 2B.

The reinforcing structure 1b formed by the metal edge seal in the edge region of the door body 1L, 1R of the APU door D may be arranged only on the outside of the door body, only on the inside of the door body or on both the inside and outside of the door body, depending on the use requirements and design requirements.

The construction of APU door D is explained in more detail below in connection with fig. 3A to 11.

In fig. 3A and 3B a sealing structure 2 for APU door D is shown. In operation, to avoid leakage of the liquid inside the APU compartment via other structures in addition to the draining of the liquid drain assembly 5, and to ensure liquid tightness inside and outside the compartment, a sealing structure 2 is provided for the APU compartment door D.

In the embodiment shown, the sealing structure 2 is arranged in segments. In the context of the present invention, a seal arrangement or seal arrangement is intended to indicate that the seal is not formed between the junctions of the door bodies 1L, 1R by separate, continuous seals. In contrast, as shown in fig. 3A, the sealing structure 2 is constituted by a plurality of discrete, independent sealing units 2f and a barrier 2d connecting these sealing units 2 f.

Specifically, in fig. 3A, the seal structure 2 is constituted by four seal units 2f and three baffles 2d connecting the four seal units 2 f. It should be noted that in use, it is possible to provide a sealing structure 2 consisting of more or less sealing units 2f and baffles 2d connecting the sealing units 2f, depending on the specific configuration of the hatch. The intervals between the sealing units 2f may be uniformly arranged or non-uniformly arranged.

In fig. 3B, a cross section of the sealing unit 2f is shown, which is taken along the line B-B in fig. 3A. As can be seen in fig. 3B, one sealing unit 2f of the sealing structure 2 comprises a seal 2a, a first seal bead 2B and a second seal bead 2c. In the present embodiment, the first sealing bead 2b is also called "high sealing bead", and the second sealing bead 2c is also called "low sealing bead". The high sealing bead 2b and the low sealing bead 2c are respectively provided with a first part 2b1 and a second part 2c1; second portions 2b2, 2c2; the third portions 2b3, 2c3, and the two seal beads 2b, 2c are mounted at the two door bodies 1L, 1R, respectively. The two sealing beads 2b, 2C are configured asymmetrically, wherein the high sealing bead is configured in the embodiment shown as a "Z" and the low sealing bead is configured in the embodiment shown as a "C" and the first part 2b1 of the high sealing bead 2b is longer than the first part 2C1 of the low sealing bead 2C, and with both sealing beads in place the first part 2b1 of the high sealing bead 2b extends obliquely upwards above the first part 2C1 of the low sealing bead 2C, so that an opening G is formed between them through which opening G the seal 2a fixed at the second part 2b2 of the first sealing bead 2b can be accessed. In an embodiment not shown, the seal 2a may alternatively be fixed at the second sealing bead 2c.

It should also be noted here that the portion of the seal 2a shown in fig. 3B that exceeds the second portion 2c2 of the second sealing bead 2c is only a dimension that schematically shows the seal 2a in the unpressed condition. In actual use, the seal 2a is entirely located only in the gap between the second portion 2b2 of the first sealing bead 2b and the second portion 2c2 of the second sealing bead 2c.

When the door D is closed, the first sealing bead 2B located on the right side in fig. 3B is closed first, and then the second sealing bead 2c located on the left side in the drawing starts to press the sealing member 2a along with the closing of the door D, finally, the sealing fixation of the second sealing bead 2 c-sealing member 2 a-first sealing bead 2B is obtained, and as can be seen in the broken line part in fig. 2B, the gap G between the first sealing bead 2B and the second sealing bead 2c is closed, so that the liquid is prevented from entering the space to corrode the sealing member 2a and accumulating in the space to cause risks.

It can also be noted in fig. 3B that the mounting direction of the seal 2a in the segmented seal structure 2 of the APU door D, i.e. the direction of the resilience of the seal 2a, is arranged perpendicular to the opening direction of the APU door D. This makes it possible to avoid an additional abutment step between the door bodies 1L, 1R of the APU door D even if the compression of the seal 2a is large. The gap between the door bodies 1L and 1R of the APU cabin door D is shielded by the sealing piece 2a of the sealing structure 2, so that the aerodynamic appearance of the APU cabin door D is not influenced, and the adverse influence on the overall aerodynamic performance of the aircraft due to the APU cabin door D in the aircraft flight is avoided.

The seal-shaped surface in the seal structure 2 of the sectional construction employed in this embodiment is simpler and facilitates mass production and lower manufacturing costs than conventional seal structures arranged in whole segments along the door body of the APU door.

Due to the segmented arrangement of the sealing elements of the sealing arrangement 2, it is not necessary to avoid or bypass the region of the APU door D on which the lock assembly 3 is provided when the sealing arrangement 2 is arranged. In other words, the sealing structure 2 of the segmented construction is better able to conform to the construction of the junction of the door bodies 1L, 1R of the APU hatch, and the support structure modification for the sealing structure 2 is also simplified, and the sealing structure 2 is compact in shape and lighter in weight. The overall installation space requirement of the sealing structure 2 is smaller, the sealing structure is more convenient to install, and meanwhile, the liquid isolation capability of the inside and the outside of the APU cabin is ensured.

Returning to fig. 1, as shown, a lock assembly 3 is provided in the middle of the door bodies 1L, 1R. In the embodiment shown, the lock assembly 3 is provided with a partial fire protection cover 3b, as can be seen in fig. 4, 5 and 6.

Turning to fig. 4 to 6, the lock assembly 3 comprises a first lock abutment 3a and a second lock abutment 3c, which are formed in a housing-like manner, the parts of the lock assembly 3 constituting the locking mechanism being enclosed by the first lock abutment 3a and the second lock abutment 3c, which are not explained in more detail here for the sake of brevity, since they are not relevant to the subject matter of the present invention.

The first support 3a adopts a known configuration. The first lock bearing 3a and the second lock bearing 3c are each itself made of a fire-resistant metallic material. A fire protection cover 3b is provided on the outside of the first lock support 3a in a cladding manner. The fire-proof cover 3b is relatively small and made of fire-proof metal. The provision of a small fire protection cover 3b allows the mechanism of the lock assembly 3 to be externally covered with fire protection, thereby enabling the use of lightweight but non-fire resistant parts, such as aluminum alloys or the like, for the mechanism parts of the specific area of the APU door D. Such parts include, but are not limited to, a mechanism adjustment shim in the lock assembly 3. In this way, while guaranteeing the fire resistance of the APU door D, the weight of the APU door D as a whole is reduced and the manufacturing cost is reduced. The mechanism of the lock assembly 3 is thus protected from exposure to flames in the event of a fire and allows parts of the lock assembly 3 that are not fire-proof to be protected, at least for a certain period of time.

Compared with the prior integral fireproof blanket adopted for the APU cabin door D, the locally arranged fireproof cover 3b is more flexible in arrangement, occupies less space, is lighter in structure weight and is lower in cost.

Also thanks to the sealing structure 2 of the above-described segmented construction and to the lock assembly 3, which can be made of a lightweight but non-fireproof material, an overall weight reduction of the APU door D is achieved, and thanks to the low weight index of the door body 1L, 1R made of composite material, the hinge assembly 4 for connecting the APU door D to the door frame, shown in fig. 1, can take the form of a single point of limited axial freedom. The construction is such that the relative positions of the door bodies 1L, 1R in the axial direction of the hinge can be controlled by adjusting the relative positions of the hinge at a single place in the hinge assembly 4 and the door frame base of the APU door D, so that the overall installation cost of the APU door D is low.

Specifically, in the illustrated embodiment, the hinge assembly 4 includes a plurality of gooseneck hinges 41. Turning to FIG. 7, a single gooseneck hinge 41 is shown. The body of the gooseneck hinge 41 is configured with an elongated bend shaped like a gooseneck. The door bodies 1L, 1R of the APU door D are each provided with a hinge assembly 4 for hinging the door body to the door frame. Each hinge assembly 4 includes a plurality of hinge arms in which only one gooseneck hinge 41 is limited in its freedom of translation in the axial direction, while the remaining hinge arms are free to translate in the axial direction.

This arrangement can prevent the occurrence of assembly stress due to over-constraint during the installation of the APU door D. When the APU door D with such a hinged arrangement adjusts its position in the direction of the axis of rotation, it is only necessary to adjust the position of a single gooseneck hinge 41 on the door frame. In this way, the assembly process of the APU door D is simplified and the cost is reduced.

Furthermore, the fire shield 3b, the baffle plate 2d, the first lock support 3a and the second lock support 3c provide shielding of the door structure opening and provide flow guiding functions, thereby preventing liquid in the APU compartment from leaking out of the gap of the lock assembly 3. Such an arrangement achieves a local liquid isolation function.

Returning to fig. 6, in the embodiment shown, a baffle plate 2d is provided in the region of the connection of the sealing structure 2 with the lock assembly 3 in a segmented configuration. The baffle plate 2d, the first sealing bead 2b and the second sealing bead 2c are arranged in a structure from high to low so as to realize shielding of the internal structure. The arrangement is such that liquid leaking from the system in the upper part of the APU door D will be led along the baffle 2D, the first seal bead 2b to the door body 1L, 1R, which is made of composite material on both sides.

The second sealing bead 2c is provided with an elongated flange 2e at the point of engagement with the second lock abutment 3c of the lock assembly 3. The provision of the bead 2e prevents liquid from escaping into the area sealed by the seal 2a, the first seal bead 2b and the second seal bead 2c. Such a structure may avoid the accumulation of combustible liquid in the crevices of the structure of APU door D, which would increase the risk of corrosion and fire.

Turning finally to fig. 8 to 11, the liquid discharge arrangement of APU door D is shown.

In the shown embodiment the APU compartment door D is provided with a continuous recess at the lower point of the door bodies 1L, 1R of the two compartment doors, respectively, for receiving liquid from the APU compartment. The received liquid here continues to flow along the two grooves to the liquid discharge openings 5L, 5R of the liquid discharge assembly 5 arranged at the lowest point of the door body 1L, 1R of the APU door and is discharged outside the APU door via these liquid discharge openings 5L, 5R, whereby the risk of liquid remaining in the structural gap of the door D causing corrosion is reduced. The flow path of the liquid from the APU compartment along the two grooves provided at the lowest of the two doors 1L, 1R of the APU compartment D, eventually to the liquid discharge ports 5L, 5R is shown by arrows in fig. 8, respectively.

Further, in order to ensure the liquid collecting effect of the liquid discharge ports 5L, 5R regions and to promote their resistance to deformation, a reinforcement 5a for the liquid discharge ports 5L, 5R is provided in the region of the liquid discharge ports 5L, 5R of the APU compartment door D, which is shown separately in fig. 9. The reinforcement 5a is fastened to the door bodies 1L, 1R by means of fasteners not shown in the drawings. The reinforcement 5a of one-piece construction is made of metal. The reinforcement 5a is provided with two through holes 5a1, 5a2. When the reinforcing member 5a is attached to the door bodies 1L, 1R, the through holes 5a1, 5a2 are aligned with the liquid discharge ports 5L, 5R provided at the door bodies 1L, 1R, respectively. In the embodiment shown, the reinforcement 5a is formed with two downwardly concave parts 5a3, 5a4. In other embodiments, the stiffening members may also be manufactured separately for the liquid discharge openings of the door body of the APU door, as desired, the shape of the stiffening members being configured to adapt to the surface shape of the region of the door body of the APU door where the liquid discharge openings are provided.

As shown in fig. 10, liquid discharge pipes 5b1 and 5b2 are provided in the corresponding areas outside the APU door D. The drain pipes 5b1, 5b2 are installed to completely cover the drain ports 5L, 5R, respectively, and are in fluid communication with the drain ports 5L, 5R, respectively, and further connected with the pipe members 5c1, 5c 2. The arrangement of the liquid discharge pipes 5b1 and 5b2 can prevent liquid from the front side of the machine body from reversely flowing into the APU cabin through the liquid discharge ports 5L and 5R, so that the liquid isolation inside and outside the APU cabin is ensured.

Furthermore, the APU hatch D of the present invention is also provided with a drain interface 6 of a chambered system, which is shown in fig. 11. The drain port 6 is also made of a fire-proof material to meet fire-proof requirements. The arrangement of the drain port 6 allows the APU system to drain excess liquid in separate chambers. In particular, in the embodiment shown in fig. 11, the drain connection 6 is provided with two openings which do not pass through each other, which are matched by the door wall of the APU cabin to the drain fairing of the chambered system outside the door, and the cabin interior is in contact with the system chambered seal.

The present invention can be freely combined with each other, or can be appropriately modified and omitted within the scope of the present invention.

Claims (11)

1. A door (D) of an auxiliary power compartment of a civil aircraft, comprising:

a door body (1L, 1R) made of a composite plate material;

a sealing structure (2) arranged along the junction of the door bodies (1L, 1R);

a lock assembly (3) provided at the door body (1L, 1R);

a hinge assembly (4) for hinging the door body (1L, 1R) to a door frame;

a liquid discharge assembly (5) provided in each of the door bodies (1L, 1R); and

a liquid discharge interface (6) arranged at least one door body and used for a cavity-separating system,

the door is characterized in that the sealing structure (2) is arranged at the joint of the door bodies (1L, 1R) in a sectionalized manner, wherein the sealing structure (2) comprises at least two sealing units (2 f) which are independent from each other, the sealing units (2 f) are connected through a baffle plate (2 d), and each sealing unit (2 f) comprises a sealing piece (2 a), a first sealing pressing strip (2 b) and a second sealing pressing strip (2 c).

2. Cabin door (D) of an auxiliary power cabin according to claim 1, characterized in that the first sealing bead (2 b) and the second sealing bead (2 c) are formed asymmetrically.

3. Cabin door (D) of an auxiliary power cabin according to claim 2, characterized in that the seal (2 a) is fixed at the first sealing bead (2 b) and that a first part (2 b 1) of the first sealing bead (2 b) extends over a first part (2 c 1) of the second sealing bead (2 c), that a gap (G) is formed between the first part (2 b 1) of the first sealing bead (2 b) and the first part (2 c 1) of the second sealing bead (2 c), through which gap (G) the seal (2 a) is accessible, and that the gap (G) is closed when the cabin door (D) is closed.

4. A door (D) of an auxiliary power compartment according to claim 3, characterized in that the lock assembly (3) comprises a first lock abutment (3 a) and a fire protection cover (3 b), the fire protection cover (3 b) being arranged to encase the first lock abutment (3 a) on the outside.

5. Cabin door (D) of an auxiliary power cabin according to claim 4, characterized in that the lock assembly (3) further comprises a second lock abutment (3C), which second lock abutment (3C) engages with the second sealing bead (2C) and that an elongated flange (2 e) is provided at the location where the second lock abutment (3C) engages with the second sealing bead (2C).

6. Cabin door (D) of an auxiliary power cabin according to any one of claims 1 to 5, wherein the drain assembly (5) comprises a drain (5L, 5R) arranged at the lowest part of the door body (1L, 1R).

7. Cabin door (D) of an auxiliary power cabin according to claim 6, characterized in that the door bodies (1L, 1R) are provided with receiving portions, respectively, for receiving liquid from the auxiliary power cabin and that the receiving portions are in fluid communication with the liquid discharge openings (5L, 5R).

8. Cabin door (D) of an auxiliary power cabin according to claim 7, characterized in that a reinforcement (5 a) is provided at the drain (5L, 5R), which reinforcement comprises a recess (5 a3, 5a 4), and that a through-hole (5 a1, 5a 2) is provided in the recess (5 a3, 5a 4), which through-hole (5 a1, 5a 2) is aligned with the drain (5L, 5R), respectively.

9. Cabin door (D) of an auxiliary power cabin according to claim 8, characterized in that on the outside of the cabin door (D) there is a drain (5 b1, 5b 2) in fluid communication with the drain (5L, 5R) and that the drain (5 b1, 5b 2) and the reinforcement (5 a) are arranged on opposite sides of the drain (5L, 5R).

10. Cabin door (D) of an auxiliary power cabin according to any one of claims 1 to 5, wherein the hinge assembly (4) comprises a plurality of gooseneck hinges (41), wherein the translational freedom of one of the gooseneck hinges (41) in the axial direction is constrained.

11. Civil aircraft, characterized by comprising an auxiliary power pod and a door (D) according to any of claims 1 to 10 for said auxiliary power pod.