CN117775264A - Connecting structure for connecting outer wing back beam and central wing back beam of aircraft - Google Patents

Abstract

A connection structure for connecting a centre wing back beam and an outer wing back beam of an aircraft, wherein the connection structure comprises a three-fork joint to which the centre wing back beam and the outer wing back Liang Fenbie are force-transmissively connected, a back beam frame being provided at the back beam region, and the connection structure comprises a diagonal bracing structure which is force-transmissively connected with the back beam frame for supporting the back beam frame, the connection structure further comprising a centre wing inner angle box and a centre wing outer angle box, wherein the centre wing inner angle box and the centre wing outer angle box are force-transmissively connected to the centre wing back beam, respectively, and the centre wing inner angle box and the centre wing outer angle box are oppositely arranged with respect to one fork of the three-fork joint. The diagonal strut panel structure is in force-transmitting connection with the central wing outer corner box, thereby sharing the primary lift load from the outer wing to the middle fuselage. The connecting structure has high structural efficiency and good maintainability, and the manufacturability and the economy are improved. An aircraft comprising the connection structure is also proposed.

Description

Connecting structure for connecting outer wing back beam and central wing back beam of aircraft

Technical Field

The present invention relates to a central wing part of a civil aircraft. Specifically, the invention provides a connecting structure for connecting an outer wing back beam and a central wing back beam of an airplane in a wing back beam area of the airplane, and belongs to a supporting structure of the central wing and a fuselage. The invention further provides an aircraft with the connecting structure.

Background

In civil aircraft, the connection of the wing beam root is a region in which the loads are significant and complex. To reduce the stress concentration level in this area, a gusset structure is typically designed to connect the wing back rail to the fuselage sidewall panel. However, the design of the diagonal strut panel structure can significantly affect the assemblability, structural efficiency, serviceability of the area structure, e.g., whether maintenance personnel are easily accessible during maintenance, whether components are easily replaced, etc.

Furthermore, a connection structure for connecting a center wing back beam to a fuselage is known from US 86722678 B2 (publication date: 18 in 3.2014). The connection structure continues from the fuselage.

A spar connection structure for an aircraft wing is known from CN 107416183A (publication date: 12/1/2017).

From CN 211685580U (work card date: 16 of 10 th 2020) a connection mechanism for connecting a central wing to a central fuselage is known.

The following three types of civil aircraft are currently known in the art as model A, B, C, and the connection structure of their rear beam regions will be explained below.

Fig. 1 shows a back beam region of the existing a-model. In the wing back spar region of model a, no fuselage frames are arranged, so that a diagonal strut AS must be arranged for carrying the lift load of the outer wing, see part (b) in fig. 1. AS can be seen in fig. 1, in model a, the interface between the center wing back beam and the outer wing back beam employs a three-prong joint which in turn connects with the tee AS shown in sections (a) and (b) of fig. 1 to form a four-prong structure. Here, the side edges of the diagonal strut AS are connected to the T-piece, while the underside of the diagonal strut AS is connected to the outer extension of the butt strap.

In the back beam area of the A model, the structure of the inclined supporting plate AS is larger, and the structure efficiency is low. Furthermore, as shown in parts (b) and (c) of fig. 1, at the lap joint on the center and outer wing back beams, the thickness of the beam may increase significantly, resulting in a large design gap AG with the trifurcated joint.

The back beam region of the existing B model is shown in fig. 2. Unlike the above-described model a, the model B is provided with a back beam frame BF in the back beam region. In model B, the interface between the center wing back beam BCB and the outer wing back beam BOB employs a four-pronged joint BFJ. In this model, too, a diagonal strut BS is provided. The side edges of the gusset BS are connected to the four-prong joint BFJ, while the underside of the gusset BS is connected to the extension of the lower edge strip of the aircraft rib No. 1 (the stiffening rib of the wing root). As can be seen in fig. 2, in this model, the back frame BF is disposed on the same side of the four-prong BFJ as the center wing back frame CBC, and the back frame BF is in direct contact with the center wing back BCB, which in turn is in direct contact with the four-prong BFJ. The outer wing back beam BOB is then connected to the other fork of the four-fork joint BFJ by means of the butt strap BDP.

In this arrangement of type B, although it is more direct to the sharing of outer wing load, the stress condition of the four-fork joint BFJ is complex and, due to its stress condition, relatively more material is used to ensure structural reliability. In addition, the maintainability of the connection structure is low. In particular, as shown in fig. 2, if the four-way joint BFJ is to be serviced or replaced, it is necessary to first remove the individual components mounted thereon, and disconnect them from the four-way joint BFJ. This makes the maintenance process complicated and time consuming.

The back beam region of the existing C-model is shown in fig. 3. Similarly to the B model, the C model is also provided with a back beam frame CF in the back beam region. The butt joint between the center wing back beam CCB and the outer wing back beam COB is realized in the model C by means of the three-fork joint CTJ. As can be seen in fig. 3, the center wing back beam CCB and back frame CF are connected in the back beam region by a butt strap CDP to a fork of the furcation CTJ and they are located on either side of the butt strap CDP. The outer wing back beam COB is then connected to the other fork of the three fork joint CTJ by means of the other butt strap CDP, similar to the B model. The side edges of the gusset CS provided in the back beam region of the C-type are connected to the back beam frame CF, and the lower side CS thereof is connected to a further pair of butt strap plates, not shown in the figure.

In this arrangement of the C-type, the maintainability of the structure is also low and the structure of the gusset CS is also large, which in turn results in a low structural efficiency of the connection structure. In addition, in this structure, the back frame CF is also subjected to a complicated bending moment load, and is more likely to fail due to stress concentration.

Accordingly, it is desirable in the art to provide a new connection structure for connecting an outer wing back rail and a center wing back rail of an aircraft that can improve at least one of the drawbacks of the above-described existing type connection structure, improve the structural efficiency of the connection structure, and/or improve the maintainability of the connection structure.

Disclosure of Invention

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a connection structure for connecting a center wing back beam and an outer wing back beam of an aircraft. The structure efficiency of the connecting structure is improved, in other words, the load transfer is smoother, and the maintainability of the connecting structure is also improved.

The connection structure according to the invention for connecting a centre wing back rest and an outer wing back rest of an aircraft is realized in such a way that the connection structure comprises a three-fork joint, a bracing plate structure, a centre wing inner angle box and a centre wing outer angle box, wherein the three-fork joint comprises a first fork, a second fork and a third fork, wherein the centre wing back rest is force-transmissively connected to the second fork of the three-fork joint and the outer wing back rest is force-transmissively connected to the third fork of the three-fork joint, the aircraft is further provided with a back rest frame at the back rest region, and wherein the bracing plate structure is force-transmissively connected with the back rest frame for supporting the back rest frame, wherein the centre wing inner angle box and the centre wing outer angle box are force-transmissively connected to the centre wing back rest, respectively, and the centre wing inner angle box and the centre wing outer angle box are oppositely arranged with respect to the second fork of the three-fork joint.

According to the connecting structure, the central wing external corner box and the central wing internal corner box are arranged to form double-shear force transmission of the butt joint mechanism of the central wing back beam and the external wing back beam, so that the structural efficiency of the connecting structure is improved.

In the context of the present invention, "force-transmitting connection" means that a load can be further transmitted to other components or structures by the two components being connected. In this context, such connection is typically achieved by means of a fastener connection, unless otherwise indicated.

For example, in one non-limiting embodiment of the invention, the center wing inner angle box may be connected to the web of the center wing back beam by fasteners, while the center wing inner angle box may be fixedly connected to the two prongs of the trifurcated joint and fixedly connected to the rim of the center wing back beam.

Preferably, in the connection structure according to the invention, the gusset is connected in force transmitting relation with the central wing outer corner box, for example by means of fasteners, so as to share the main lift load transmitted from the outer wing and transmit it to the central fuselage of the aircraft.

Desirably, in a preferred embodiment of the present invention, the connection structure according to the present invention further comprises an outer wing inner angle box and an outer wing outer angle box, wherein the outer wing inner angle box is fixedly connected with the two prongs of the trifurcated joint similarly to the central wing inner angle box and is force-transitionally connected with the outer wing back beam. The outer wing outer corner box is arranged on the outer side of the three-fork joint, and one fork part of the three-fork joint is arranged opposite to the outer wing inner corner box.

In particular, the outer-wing inner corner box has a first flange and a second flange. The inner corner box of the outer wing is arranged such that the first flange is fixedly connected to the outer wing back beam, for example the web of the outer wing back beam, and the second flange is fixedly connected to the outer wing back Liang Mengpi, thereby providing load transfer and support to the outer wing back beam.

Desirably, in a further preferred embodiment of the present invention, the connection structure according to the present invention comprises a central wing outer corner box having a first side cuff, a second side cuff and a lower cuff. In this case, the diagonal strut structures of the connection structure are respectively connected to the first side flange and the lower flange of the center wing outer corner box, and the second side flange of the center wing outer corner box is fixedly connected to the center wing back rail, thereby providing load transfer and support to the center wing back rail.

Desirably, in a preferred embodiment of the present invention, the gusset structure of the connection structure is formed of a gusset and a gusset support, as opposed to the single piece of gusset construction as in the B, C version described initially.

In the gusset structure of the connection structure according to the invention, the gusset is connected at the side edge to the back frame of the aircraft and to the first side flange of the centre wing skin angle box, i.e. the side flange of the centre wing skin angle box which is not fixedly connected to the web of the centre wing back beam, and the gusset support is connected at its bottom to the lower flange of the centre wing skin angle box by means of a fastener, preferably a plurality of fasteners.

The modular construction of the diagonal bracing plate structure improves the manufacturability and economy of the structure compared to the prior art models described above.

Still preferably, in a preferred embodiment of the present invention, the length of the portion of the gusset plate of the gusset structure of the connecting structure that is connected to the back frame of the aircraft on the side edge is smaller than the length of the portion that is connected to the first side flange of the center wing skin angle box. That is, the side edges of the diagonal brace panels are mainly connected with the first side flanges of the center wing outer corner box for load transfer, and the side edges of the back frame are partially connected with the side edges of the back frame for supporting the back frame. Thus, the strut plate structure is started to bear the lift load from the lower end of the outer wing back beam. The connecting structure according to the invention has a high lift load efficiency.

In an alternative embodiment of the invention, the diagonal strut plates in the diagonal strut plate structure are configured as triangular plates.

In another alternative embodiment of the invention, the diagonal strut supports in the diagonal strut plate structure are configured as hexagons.

Preferably, the hexagonal configuration of the diagonal strut supports in the diagonal strut plate structure is such that two opposite sides are parallel respectively.

Optionally, the bottom edge of the hexagonal diagonal strut supports supported at the central wing outer corner box is one of the shortest set of sides of the hexagon.

Preferably, a plurality of reinforcing ribs are provided inside the diagonal brace plate of the diagonal brace plate structure for reinforcing the strength of the diagonal brace plate and the transmission of load.

In a further preferred embodiment of the invention, the connection structure according to the invention further comprises a connection strap connecting the central wing lower wall skin and the outer wing lower wall skin of the aircraft. In particular, a first end of the connection strap is fixedly connected to a central wing lower wall skin of the aircraft, and a second end of the connection strap opposite the first end is fixedly connected to an outer wing lower wall skin of the aircraft.

Preferably, the connection strap is disposed under rib No. 1 of the aircraft.

Further preferably, the bottom of the diagonal strut panel support, the partial extension of the central wing lower wall skin and the partial extension of the connecting band panel are connected together by means of one or more fasteners, such that the connection structure according to the invention effectively shares the shear load transferred from the outer wing lower wall panel, reduces the shear load of the central wing lower wall panel, and improves the efficiency of the area structure

It is also preferable that at the second end where the connection band plate is connected to the outer wing lower wall skin, the second flange of the outer wing outer corner box, the local extension of the outer wing lower wall skin and the local extension of the connection band plate are fixedly connected together to improve the structure of the local extension of the connection band plate, so that the shear load generated by the outer wing torque can be smoothly transferred to the central wing lower wall plate and the diagonal brace plate, stress concentration is avoided, load transfer is smooth, and structural efficiency is improved.

In summary, the connection structure according to the present invention can avoid the situation that the stress concentration is caused by the excessive concentration of the load transferred by the local outer wing, and thus the local fatigue or fracture failure is caused, and by improving the load transfer situation, the amount of materials used in the manufacturing process of the connection structure can be reduced, the manufacturing cost is reduced, and the weight reduction is realized to a certain extent compared with the connection structure used in the existing model.

The invention thus advantageously increases the structural and assembly efficiency of the aircraft. Furthermore, the use of separate inner and outer corner boxes improves the maintainability of the connection structure according to the invention, so that the structure or parts thereof become more accessible to maintenance personnel when maintenance is required than in connection structures of the prior art. Particularly, the use of the external corner box effectively promotes the transmission of upward lifting load.

Furthermore, the connection structure according to the invention allows the fuselage frame end structure to avoid potential fatigue problems.

Thus, the connection structure according to the invention is very well balanced in terms of economy, reliability and practicality.

In addition, the invention also provides an aircraft. The aircraft has a center wing back spar and an outer wing back spar, and the aircraft has a connection structure for connecting the center wing back spar and the outer wing back spar, the connection structure being constructed as described in any of the preceding aspects.

Drawings

The above technical and other features of the present invention will be explained hereinafter with reference to the embodiments shown in the drawings, which are intended to be understood as illustrative and not limiting.

Fig. 1 is a perspective view showing a connection structure of a center wing back beam and an outer wing back beam of a model a in the prior art;

fig. 2 is a cross-sectional view showing a connection structure of a center wing back beam and an outer wing back beam of another model B in the related art;

FIG. 3 is a cross-sectional view showing a connection structure of a center wing back beam and an outer wing back beam of another model C according to the prior art;

fig. 4A shows a perspective view of the connection structure of the present invention in a connected state with the center wing back beam and the outer wing back beam;

fig. 4B shows a perspective view of the center wing back beam, the outer wing back beam, and the trifurcated joint in the connecting structure in the connected state;

FIG. 5 shows a cross-sectional view taken along line A-A of FIG. 4A;

FIG. 6 shows a cross-sectional view taken along line B-B of FIG. 4A;

FIG. 7 illustrates a diagonal strut structure in the connection configuration shown in FIG. 4A;

FIG. 8 illustrates the connection structure shown in FIG. 4A in a perspective view from another angle;

FIG. 9 shows the diagonal strut plate structure of FIG. 7 in a connected state in a perspective view;

FIG. 10 shows the center wing outer angle box and back frame in a connected state in a perspective view;

fig. 11 is a perspective view, viewed at another angle, showing the outer-wing outer-angle box and the central-wing outer-angle box in a connected state;

FIG. 12 shows in perspective view the outer corner box of the outer wing and the connection details between the outer corner box of the central wing and the lower wall skin;

FIG. 13 is a perspective view, viewed at another angle, showing details of the connection between the outer corner box of the outer wing and the central wing outer corner box and the lower wall skin; and

fig. 14 shows the connection detail between the connection band plate and the lower wall skin from below.

List of reference numerals:

AG (of prior art type a) gap

AS (of the prior art A model) diagonal bracing

AT (in prior art model A) tee

BCB center wing back (of prior art B model)

BDP (of prior art model C) butt strap

Back beam frame of BF (in B model of the prior art)

Four-prong joints (of type B prior art)

BOB (of type B prior art) outer-wing trailing beam

BS (of type B prior art) diagonal bracing

Center wing back beam of CCB (of prior art type C)

COB (of type C prior art) outer wing back beam

CDP (of prior art model C) butt-joint band plate

Back beam frame of CF (of prior art type C)

CS (of type C prior art) diagonal bracing

CTJ (of type C prior art) trifurcated joint

PCS connection structure

101. Central wing back beam

102. Inner corner box with central wing

103. Central wing trailing beam edge strip

104. Central wing back beam web

105. Central wing external corner box

1051 Side flanging (of central wing external corner box)

1052 Lower flange (of central wing outer corner box)

1053 and diagonal strut 401 connection

1054 to the gusset support 402 connection

106. Central wing lower wall skin

201. Outer wing back beam

202. Inner corner box with outer wing

203. Outer wing and outer corner box

2031 Lower flange (of outer wing outer corner box)

204. Outer wing lower wall skin

301. First butt-joint band plate

302. Second butt-joint band plate

40. Diagonal bracing plate structure

401. Inclined supporting plate

4011 Reinforcing rib (of inclined supporting plate)

4012 Lower side edge (of inclined supporting plate)

4013 Side edge connection (of diagonal strut)

402 diagonal bracing plate support

4021 Upper side edge (of diagonal strut support member)

4022 Reinforcing bar (of diagonal bracing plate support member)

4023 Bottom attachment zone (of diagonal strut support)

501 back beam frame

5011 and diagonal brace 401 joint

701. Three fork joints

7011. A first fork part

7012. A second fork

7013. Third fork part

801. Upper edge strip

901. Fastening piece

Detailed Description

While the invention will be described in conjunction with the exemplary embodiments, those skilled in the art will appreciate that the present description is not intended to limit the invention to such exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiment but also various alternatives, modifications, equivalents, and the like, 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, unless otherwise indicated.

Hereinafter, a connection structure for connecting an outer wing back beam with a center wing back beam according to the present invention will be explained in detail with reference to fig. 4 to 10, and is generally given the reference numeral PCS.

Fig. 4A shows a perspective view of a connection structure PCS, in the back beam region of an aircraft provided with this connection structure PCS, a back beam frame 501 is provided. The connection between the center wing back rail 101 and the outer wing back rail 201 is achieved in the connection structure PCS by means of a trifurcated joint 701. As explained in more detail below in connection with fig. 4A through 14.

Only the center wing back spar 101, the outer wing back spar 201, and the trifurcated joint 701 of the aircraft are shown in fig. 4B for clarity.

Reference is first made to fig. 5 and 6, which are sectional views taken along lines A-A and B-B, respectively, in fig. 4.

It should be noted that the above references to fig. 2, 3 illustrating the connection structure in the existing model B and the existing model C are also cross-sectional views cut in a similar way at the corresponding positions of the connection structure of the center wing back and the outer wing back of the respective model, with the purpose of clearly showing the connection between the trifurcate or tetrafork joint in the respective connection structure and the center wing back BCB, CCB and the outer wing back BOB, COB and also the back frames BF, CF of the respective model aircraft.

Turning now to fig. 5, the cross-section taken along section line A-A shown in fig. 5 is closer to upper rim 801 than the cross-section taken along section line B-B shown in fig. 6.

The three-fork joint 701 here connects the central wing back spar 101 and the outer wing back spar 201 of the aircraft.

Here, the center wing trailing edge strip 103 of the center wing trailing beam 101 is connected to the trifurcated joint 701 by the center wing inner angle box 102 and the center wing trailing beam web 104, wherein the center wing inner angle box 102 is flanged against the first prong 7011 of the trifurcated joint 701 on one side and the second prong 7012 of the trifurcated joint 701 on the other side.

Here, the outer wing back beam 201 is connected to the third prong 7013 of the three prong joint 701 by the first butt strap 301. In addition, the connection structure PCS is further provided with an outer wing inner corner box 202 abutting against the three-fork joint 701. Specifically, one side flange of the outer wing inner corner box 202 abuts against the first prong 7011 of the trifurcated joint 701, while the other side flange of the outer wing inner corner box connects to the outer wing back 201 and abuts against the third prong 7013 of the trifurcated joint 701. In the illustrated embodiment, the outer wing inner corner box 202 and the center wing inner corner box 102 are each connected to the trifurcate joint 701, for example, by fasteners.

Here, a back beam frame 501 is provided in the back beam region, the back beam frame 501 being supported by the diagonal strut 401 in the diagonal strut plate structure 40, as will be explained in more detail below with reference to fig. 10.

Turning now to fig. 6, the cross-section shown in fig. 6 is taken along line B-B at a lower elevation.

As can be noted by comparing fig. 5 and 6, a central wing outer corner box 105 is also provided at the lower level of the connecting structure PCS. In addition, a diagonal strut plate support 402 is provided for the diagonal strut plate 401.

Here, the central wing outer angle box 105 is disposed between the second prong 7012 of the trifurcated joint 701 and the diagonal strut plate 401, being force-transmissively connected to the trifurcated joint 701 by the central wing back web 104.

In the connection structure PCS, by providing the central wing outer corner box 105, the double shear force transmission in the connection structure PCS of the central wing rear beam and the outer wing rear beam is formed with the central wing inner corner box 102, thereby making the structure reasonable and the structure efficient, wherein the central wing outer corner box 105 and the central and inner corner boxes 102 are respectively arranged at both sides of the second fork 7012 of the trifurcate joint 701.

The diagonal strut plate structure 40 used in the connection structure PCS is explained in detail next. Referring first to fig. 7, a diagonal strut plate structure 40 of the present invention, unlike the diagonal strut plates BS, CS of the prior art type described at the outset, is a combined structure which is composed of a diagonal strut plate 401 and a diagonal strut plate support member 402. Such a combined structure can improve manufacturability and economy of the diagonal strut plate structure.

As shown in fig. 7, in the present embodiment, the gusset 401 is triangular in shape, and a plurality of reinforcing ribs 4011 are provided thereon. The diagonal strut plate support member 402 is a hexagonal diagonal strut structure, six sides of the diagonal strut structure are divided into three groups, opposite sides in each group are parallel to each other, and a plurality of reinforcing ribs 4022 are also included in the diagonal strut plate support member 402. At the time of installation, the upper side 4021 of the gusset support 402 is connected against the lower side 4012 of the gusset 401 by, for example, fasteners, thereby forming the gusset structure 40. When the connection structure PCS needs to be replaced or maintained, for example, the corresponding diagonal brace plates 401 or the diagonal brace plate supports 402 are replaced according to the positions of specific fault positions or failure positions, the whole diagonal brace plate structure 40 is not required to be replaced, the use cost of the connection structure PCS can be reduced to a certain extent, and the maintenance efficiency is improved.

The connection of the gusset structure 40 to other surrounding components is further explained below in connection with fig. 8-14. As shown in fig. 8, 9 and 10, the gusset 401 is connected at its side connection region 4013 to the back frame 501 and the center wing outer corner box 105, with the side edge of the gusset 401 being connected in large part to the side edge 1051 of the center wing outer corner box 105 for primary force and load transfer, and the side edge of the gusset 401 being connected in small part to the side edge of the back frame 501 for providing support to the back frame 501.

Fig. 10 shows the connection of the connection structure PCS to the diagonal strut panel structure 40 at the back frame 501 and the center wing outer corner box 105. The diagonal strut 401 and diagonal strut support 402 are omitted herein for clarity.

As shown in fig. 10, the back frame 501 and the center wing outer corner box 105 are arranged from top to bottom. The gusset 401 is fixedly connected at its side connection regions 4013 to the connection 5011 of the back frame 501 by, for example, fasteners as described above. At the side flanges 1051 of the center wing exterior angle box 105, a majority of the side attachment regions 4013 of the gusset 401 are attached to the center wing exterior angle box 105 for load transfer. Further, at the lower flange 1052 of the center wing outer corner box 105, as will be explained in detail below, the gusset support 402 of the gusset structure 40 is fixedly connected thereto. The connection of the gusset supports 402 to the lower flanges 1052 of the central wing outer corner box 105 can also be accomplished, for example, by means of threaded fasteners.

Thus, the strut plate structure 40 is initially loaded with lift loads from the lower end of the outer wing back spar 201, thereby enabling the connecting structure PCS to efficiently share the lift loads.

Referring next to fig. 11, an outer wing angle box 203 may also be provided at the outer wing lower wall skin 204 of the aircraft opposite the central wing angle box 105, as shown. As further shown in fig. 12, the lower flange 2031 of the outer wing exterior corner box 203 is fixedly connected to the outer wing lower wall skin 204, for example, by means of threaded fasteners. Similarly, the turndown 1052 of the center wing exterior angle box 105 is fixedly attached to the center wing lower wall skin 106. The outer wing lower wall skin 204 and the center wing lower wall skin 106 are in turn connected to each other by a second butt strap 302, as shown in fig. 14.

In the connection structure PCS, by connecting the outer wing outer corner box 203, the partial extension of the outer wing lower wall skin 204, and the partial extension of the lower second butt strap 302 (also referred to as "No. 1 under-rib butt strap"), the structure of the extension end of the second butt strap 302 is improved so that the shear load generated by the outer wing torque can be smoothly transmitted to the center wing lower wall panel and the diagonal brace panel structure 40. This improves the load transfer efficiency of the overall connection structure PCS, avoiding breakage or failure caused by possible stress concentrations at the protruding end of the second butt strap 302.

Fig. 14 shows the connection of the second connection band plate 302 to the center wing lower wall skin 106 and the outer wing lower wall skin 204, as seen from below.

Another connection of the gusset structure 40, i.e., its connection with the center wing outer corner box 105 at the turndown 1052, is described next in connection with fig. 13.

As shown, the lower edge of the gusset support 402, i.e., the bottom attachment 4023 at the shortest side of the hexagonal gusset support 402 in this embodiment, is attached to the lower flange 1052 of the center wing outer angle box 105 and the partial extension of the center wing lower wall skin 106, and the partial extension of the second butt strap 302 below the center wing lower wall skin 106.

In the illustrated embodiment, the connection of the gusset supports 402 to the center wing exterior angle box 105, center wing lower wall skin 106, and second butt strap 302 is accomplished by a number of fasteners 901. Here, the fastener 901 is, for example, a bolt fastener.

With the above arrangement, the connecting structure PCS, and in particular the diagonal strut panel structure 40 therein, can effectively share the shear load transmitted from the outer wing lower wall panel, thereby reducing the shear load of the center wing lower wall panel and thereby improving the regional structure efficiency.

When installing the connection structure PCS, the specific sequence is as follows:

1. in the aft spar region of the aircraft, a trifurcated joint 701 is placed between the center wing aft spar 101 and the outer wing aft spar 201;

2. the central wing outer corner box 105 is fixedly installed on the central wing lower wall skin 106, so that the lower flange 1052 of the central wing outer corner box is in abutting contact with the central wing lower wall skin 106, the first side flange of the central wing outer corner box is abutted against the central wing rear beam 101, and the second side flange 1051 is reserved for the subsequent installation of the inclined strut plate 401;

3. mounting a second butt-strap 302 under the aircraft rib No. 1, a first end of the second butt-strap 302 abutting the central wing lower wall skin 106, preferably abutting a partial extension of the central wing lower wall skin 106, and a second end thereof opposite the first end abutting the outer wing lower wall skin 204;

4. installing a gusset structure 40, fixedly connecting the side edges of the gusset 401 to the side flanges 1051 of the center wing outer corner box 105 at a side edge connection region 4013;

5. the diagonal brace support 402 of the diagonal brace panel structure 40 is fixedly connected to the down flange 1052 of the center wing outer angle box 105 and the first end of the second butt strap 302 at the bottom connection 4023 of the bottom edge by means of fasteners 901;

6. the side edge of the gusset 401 is fixedly connected to the connection 5011 of the side edge of the back frame 501 at a position above the side edge connection area 4013.

The present invention thus proposes a new type of connection structure for connecting the central wing back-rest of an aircraft to the fuselage, which mainly comprises a connection to the back-rest frame of the aircraft and to the central wing external corner box, the former for support, the latter for load bearing, realized by the lateral connection of the diagonal strut structure 40; and includes being connected to the center wing outer corner box, center wing lower wall skin by the underside of the gusset structure 40, i.e., by the bottom connection of the gusset support 402, and to the outer wing lower wall skin by a second connection strap.

The connecting structure has high manufacturability, economy and structural efficiency resultant force. The central wing inner angle box 102, the central wing outer angle box 105, the outer wing inner angle box 202 and the outer wing outer angle box 203 are all independent components, which are convenient for manufacturing, replacement and maintenance, and therefore the maintainability of the connecting structure PCS is higher.

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 connection structure (PCS) for connecting a centre wing back spar (101) and an outer wing back spar (201) of an aircraft, characterized in that,

the connection structure (PCS) comprises a three-fork joint (701), wherein the three-fork joint (701) comprises a first fork (7011), a second fork (7012) and a third fork (7013), wherein the center wing rear beam (101) is force-transmissively connected to the second fork (7012) of the three-fork joint (701) and the outer wing rear beam (201) is force-transmissively connected to the third fork (7013) of the three-fork joint (701),

the aircraft is provided with a back beam frame (501) at a back beam region and the connection structure (PCS) comprises a diagonal strut plate structure (40), wherein the diagonal strut plate structure (40) is connected with the back beam frame (501) in a force transmission manner for supporting the back beam frame (501),

the connection structure (PCS) comprises a central wing inner corner box (102) and a central wing outer corner box (105), wherein the central wing inner corner box (102) and the central wing outer corner box (105) are respectively force-transmissively connected to the central wing back beam (101), and the central wing inner corner box (102) and the central wing outer corner box (105) are oppositely arranged with respect to a second fork (7012) of the trifurcated joint (701), and

the gusset structure (40) is force-transmissively connected to the center wing outer corner box (105).

2. The connection structure (PCS) according to claim 1, characterized in that the centre wing outer corner box (105) has a first side flange (1051), a second side flange and a lower flange (1052), wherein the gusset structure is connected to the first side flange (1051) and the lower flange (1052), respectively, and the second side flange is fixedly connected to the centre wing back rail (101).

3. The connection structure (PCS) according to claim 2, characterized in that the gusset structure (40) comprises a gusset plate (401) and a gusset plate support (402), wherein the gusset plate (401) is laterally connected to the back frame (501) and the first side flange (1051) of the center wing outer corner box (105), and the gusset plate support (402) is connected at the bottom to the down flange (1052) of the center wing outer corner box (105) by means of a fastener (901).

4. The connection structure (PCS) of claim 3 wherein the length of the portion of the gusset (401) that is laterally connected to the back frame (501) is less than the length of the portion of the first side flange (1051) that is connected to the center wing outer box (105).

5. The connection structure (PCS) of claim 4 wherein the diagonal strut plates (401) are configured as triangles.

6. The connection structure (PCS) of claim 4 wherein the diagonal strut plate (401) is internally provided with a plurality of reinforcing ribs (4011).

7. The connection structure (PCS) according to any of the claims 1-6, characterized in that the connection structure (PCS) further comprises a connection strap (302), a first end of the connection strap (302) being fixedly connected to the aircraft center wing lower wall skin (106) and a second end of the connection strap (302) opposite the first end being fixedly connected to the aircraft outer wing lower wall skin (204).

8. The connection structure (PCS) of claim 7 wherein the connection strap (302) is disposed under rib No. 1 of the aircraft.

9. The connection structure (PCS) according to claim 8, characterized in that the bottom of the gusset support (402), the partial extension of the center wing lower wall skin (106), the partial extension of the connection band plate (302) are connected together by means of the fastener (901).

10. The connection structure (PCS) of claim 9 further having an outer-wing outer-corner box (203) having an outer-wing outer-corner box side flange and an outer-wing outer-corner box down flange, wherein the outer-wing outer-corner box side flange is fixedly connected to the outer-wing back-rail (201) and the outer-wing outer-corner box down flange opposite the side flange is fixedly connected to the outer-wing lower-wall skin (204).

11. An aircraft having a centre wing back spar (101) and an outer wing back spar (201), characterized in that the aircraft has a connection structure (PCS) for connecting the centre wing back spar (101) and the outer wing back spar (201), which connection structure is constructed as claimed in any one of claims 1 to 10.