CN113911314A

CN113911314A - Keel beam edge strip connecting structure and mounting method thereof

Info

Publication number: CN113911314A
Application number: CN202111359380.4A
Authority: CN
Inventors: 樊建超; 邓珊; 宋子玲; 于振波
Original assignee: Commercial Aircraft Corp of China Ltd
Current assignee: Commercial Aircraft Corp of China Ltd
Priority date: 2021-11-16
Filing date: 2021-11-16
Publication date: 2022-01-11
Anticipated expiration: 2041-11-16
Also published as: CN113911314B

Abstract

The invention relates to a keel beam edge strip connecting structure, which comprises: a first bead and a second bead aligned in a longitudinal direction; the compression-resistant pieces are engaged between the gaps of the ends of the first flanges and the second flanges which are close to each other; and an attachment structure for holding the first and second flanges together. By the connecting structure, the keel beam can adapt to the spacing change condition which cannot be accurately controlled between the ends of the keel beam flanges to be connected, and when the keel beam flanges are subjected to large compression load, the compression resisting piece and the attachment structure jointly transmit the load; when the flange strip is subjected to a small tensile load, the load is transmitted only by the attachment structure, so that a tension-compression asymmetric structure is formed, the attachment structure does not need to have strong structural strength, the structural weight is reduced, and the load transmission efficiency is improved. The invention also relates to a method for installing the keel beam edge strip connecting structure.

Description

Keel beam edge strip connecting structure and mounting method thereof

Technical Field

The invention belongs to the field of keel beam edge strip connection of civil aircrafts, and relates to a keel beam edge strip connecting structure, in particular to a keel beam edge strip connecting structure for a civil aircraft.

The invention also relates to a method for installing the keel beam edge strip connecting structure.

Background

The airframe structures of civil aircraft, such as civil passenger aircraft/airplanes, are composed of different parts, assemblies, components, which are not natural entities but are assembled together by various means of connection, so as to form the airframe structure of the entire aircraft. Airframe structures are subjected to various types of loads from the ground to the air during takeoff and/or descent of the aircraft.

Keel beams are usually located at the bottom of the central fuselage and are an important component of civil aircraft, are used to connect the front, middle and rear of the fuselage and are mainly used to transfer the large compressive loads of the lower part of the fuselage in the course of the heading, while also bearing a portion of the tensile loads. The connection forms of different models of aircraft are also different. For example, in some aircraft, the connection is made by overlapping the bead wall panels, i.e., by overlapping portions of the bead ends, while in other aircraft the connection is made by a butt joint, e.g., by flanges at the two bead ends. For example, two T-shaped ends (e.g., circular flanges) are joined together by fasteners. However, in the prior art connection forms described above, the keel beams are required to be staggered between fuselage sections, which is detrimental to fuselage segmentation and adversely affects fuselage assembly. In addition, in order to ensure that the keel beams can bear large compressive loads, these connection structures must ensure sufficient structural strength, so that prior art keel beam connection forms are heavy in weight and inefficient in load transfer, such as in particular the form of a split joint. In addition, the inventors have found that during assembly, due to the influence of other parts in the fuselage structure or the limitations of the assembly process, it is difficult to determine precisely the distance between the ends of the consecutive flanges to be connected, which further increases the difficulty of connection/assembly.

Accordingly, there remains a need for a keel beam flange connection which overcomes one or more of the disadvantages of the prior art to facilitate fuselage assembly, reduce the weight of the keel beam, thereby reducing the overall weight of the aircraft and improving keel beam load transfer efficiency.

Disclosure of Invention

The invention aims to provide a keel beam connecting form which is suitable for the structural arrangement characteristics of a machine body, beneficial to sectional assembly of the machine body, high in load transfer efficiency, simple, reliable and light in weight.

According to an aspect of the present invention, there is provided a keel beam flange connection structure, which may include: a first bead and a second bead aligned in a longitudinal direction (e.g., a lengthwise direction of the beads); the compression-resistant pieces are engaged between the gaps of the ends of the first flanges and the second flanges which are close to each other; and an attachment structure for holding the first and second flanges together.

By the connecting structure, the keel beam can adapt to the spacing change condition which cannot be accurately controlled between the ends of the keel beam flanges to be connected, and when the keel beam flanges are subjected to large compression load, the compression resisting piece and the attachment structure jointly transmit the load; when the flange strip is subjected to a small tensile load, the load is transmitted only by the attachment structure, so that a tension-compression asymmetric structure is formed, the attachment structure does not need to have strong structural strength, the structural weight is reduced, and the load transmission efficiency is improved.

According to the above aspect of the present invention, preferably, the gap between the ends of the first and second flanges may be V-shaped, and the pressure resistant member may be a wedge-shaped spacer and have an insertion portion tapered toward the tip. Therefore, the structure of each part is simple, the space is open, the butt joint surfaces are few, and the butt joint between the flanges is convenient to connect and assemble. Meanwhile, the compression resistant pieces are engaged in the gaps by the aid of gravity of the compression resistant pieces through the wedge-shaped structures, and the compression resistant pieces can be prevented from sliding down/out of the gaps between the flanges.

According to the above aspect of the present invention, preferably, the pressure-resistant member may be provided with a protrusion extending toward the first and second flanges and away from the pressure-resistant member in the longitudinal direction. The protrusion may serve as a secondary safeguard further preventing the pressure resistant member from falling out of the gap between the flanges when the flanges are pulled.

According to the above aspect of the present invention, preferably, the inclination of the inclined surface of the insertion portion of the compression resisting member may satisfy l/h < μ, where l is a distance in the longitudinal direction between the free end distant from the protrusion and the base near to the protrusion on the side of the insertion portion, h is a height of the insertion portion, and where μ is a coefficient of friction between the first rim or the second rim and the compression resisting member.

In this way, it is ensured that a friction force of sufficient magnitude exists between the first or second rim and the pressure-resistant element, which friction force cooperates with the weight of the pressure-resistant element itself, so that the pressure-resistant element, when subjected to the compressive forces of the rims on both sides, does not slip out of the interspace between the two ends, for example, up out of the interspace.

In accordance with the above-described aspect of the present invention, preferably, the area of abutment of the compression resistant member with the end portions of the first or second flanges may be greater than 2/3 of the area of the end faces of the end portions of the first or second flanges. Thereby further ensuring that the pressure-resistant member does not slip out of the gap between the two ends when subjected to the squeezing force of the flanges on the two sides.

According to the above aspect of the present invention, preferably, the attachment structure may include a strap and a fastener for securing the strap to the first and second flanges. In this way, the keel beam edge strip of the invention can be connected firmly and reliably only by a small number of structural members.

According to the above aspect of the present invention, preferably, in order to further increase the reliability of the connection, the lap plates may include 2, and the first flanges are attached to the second flanges by means of fasteners at both sides of the ends of the first flanges and the second flanges, respectively.

According to the above aspect of the present invention, preferably, in order to better withstand the compressive load and the tensile load in the longitudinal direction, the fastener may include a shear bolt and a cooperating nut.

According to another aspect of the present invention, there is provided a method of installing the keel beam flange connection structure according to the above aspect, the method may include the steps of: an alignment step in which the first bead and the second bead are aligned in the longitudinal direction X; a pressure-resistant piece placing step, in which a pressure-resistant piece is placed between the gaps of the ends of the first and second flanges which are close to each other; and a securing step in which the first bead is attached to the second bead by means of an attachment structure.

According to the above aspect of the present invention, preferably, the step of placing the compression resistance element further comprises a grinding step in which the side of the insert portion of the compression resistance element is ground until the side of the insert portion has an area of abutment with the end of the first or second bead that is greater than 2/3 of the area of the end face of the end of the first or second bead. In this way, by grinding the compression resistance element, it is possible, on the one hand, to adjust the dimensions of the compression resistance element as a function of the distance between the ends of the first or second bead that are close to each other, so that the compression resistance element can fit as completely as possible into the space between the beads, and, on the other hand, to bring the side of the insertion portion of the compression resistance element into abutment with the ends of the beads, so as to ensure the friction therebetween.

In conclusion, the keel beam edge strip connecting structure according to the invention realizes simple interface/interface relationship among the front, middle and rear fuselage sections of the keel beam structure, realizes balance among the connecting strength, weight and process of the keel beam edge strip of the civil aircraft, and realizes the expected invention purpose.

Drawings

FIG. 1 is a schematic perspective view of a keel beam flange connection according to a non-limiting embodiment of the invention;

FIG. 2 is a schematic top view of a keel beam flange connection according to a non-limiting embodiment of the invention;

FIG. 3 is a schematic side view of a keel beam flange connection according to a non-limiting embodiment of the invention;

FIG. 4 is a schematic cross-sectional view of a keel beam flange connection according to a non-limiting embodiment of the invention;

FIG. 5 is a schematic elevation view of a compression resistance element according to a non-limiting embodiment of the present invention;

FIG. 6 is a schematic elevation view of a compression resistance element according to another non-limiting embodiment of the present invention; and

fig. 7 is a schematic view illustrating a method of installing a keel beam flange connection structure according to a non-limiting embodiment of the present invention.

The figures are purely diagrammatic and not drawn true to scale.

List of reference numbers in the figures and examples:

100-keel beam edge strip connecting structure; the method comprises the following steps:

10-first bead

11-first end

12-second end

13-first series of openings

20-second bead

21-first end

22-second end

23-second series of openings

30-compression resistant piece

31-insertion part

32-projection

33-pin hole

40-compression resistant member

41-strap

411-attachment hole

42-fastener

421-shear bolt

422-nut

X-longitudinal direction.

Detailed Description

It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the specification are simply exemplary embodiments of the inventive concepts disclosed and defined herein. Thus, unless otherwise expressly stated, specific paths of motion, directions, or other physical characteristics relating to the various embodiments disclosed should not be considered as limiting.

The inventive principle and advantageous effects of the present invention will be more clearly understood by describing in detail the keel beam flange connection structure 100 according to a non-limiting embodiment of the present invention with reference to the accompanying drawings.

Fig. 1-3 are schematic views of a keel rail connection 100 according to a non-limiting embodiment of the invention, viewed from different directions.

As shown and by way of non-limiting example, the keel beam edge strip connection structure 100 may comprise, for example: a first bead 10, a second bead 20, a compression resistant member 30, and an attachment structure 40.

The first and

second flanges

10, 20 may be flanges for a keel beam for a passenger aircraft, such as a civil aircraft, which keel beam may be located at the bottom of the mid-fuselage.

In the embodiment illustrated in the figures, the first and

second flanges

10 and 20, respectively, are shown as being elongated having a rectangular cross-section. For example, the first bead 10 may have a first end 11 and a second end 12, while the second bead 20 may have a first end 21 and a second end 22. However, it should be understood that the first and

second flanges

10, 20 may be any shape known in the art and may be formed from any material.

During the installation and attachment of the flanges, the gap between the flanges is less easily controlled precisely relative to the orientation of the flanges due to assembly process limitations, such that the gap between the ends of the first and

second flanges

10, 20 that are proximate to each other, such as the gap/gap between the second and first ends 12, 21, fluctuates in size, i.e., the dimension in the longitudinal direction X is not precisely controlled.

In the preferred embodiment, the inventors have devised a configuration that accommodates such fluctuations in the gap, such as by designing the gap between the ends (e.g., the second end 12 and the first end 21) of the first and

second flanges

10 and 20 in a V-shape. For example, the ends of the first and

second flanges

10, 20 that are adjacent to each other may be beveled and aligned in the longitudinal direction X. In this way, the orientation of first and

second flanges

10, 20 is more easily controlled, while the gap therebetween is less easily controlled, such that the gap always remains V-shaped, as reflected by the difference in the size of the V-shaped openings, with the slope of the bevels formed at their ends being constant, when the spacing between first and

second flanges

10, 20 is different.

Fig. 4 is a schematic sectional view of the keel beam edge connection structure 100 according to a non-limiting embodiment of the invention, which shows a cross-section of the keel beam edge connection structure 100 through the section a-a of fig. 2. In this fig. 4, the V-shaped void can be more clearly shown.

As described in the background section of the present application, since the keel beam flanges are subjected to a large compressive load, a compression resisting member 30 is provided between the gaps of the ends of the first and

second flanges

10 and 20 which are close to each other for this purpose. A non-limiting example of a compression resistance 30 is shown in fig. 5 and 6.

As shown and as a preferred embodiment of the present invention, the compression resistant member 30 may be a wedge-shaped pad and include an insert 31 having two opposing mating surfaces that mate with the ends of the first and

second flanges

10, 20. in a preferred embodiment, the compression resistant member 30 may also include a protrusion 32 (as described in more detail below).

The insert 31 may taper towards the tip to fit into the gap between the first and

second flanges

10, 20. In the preferred embodiment, the insert 31 is sloped on both sides facing the first and

second rims

10, 20, and the slope of these sloped surfaces corresponds to the slope of the end of the cooperating first and

second rims

10, 20, such as the slope of the surfaces of the second and first ends 12, 21.

On either side of the insertion portion 31, for example, with respect to the left side surface of the insertion portion 31 shown in fig. 5, the inclination of the inclined surface of the insertion portion 31 may satisfy l/h < μ. Where l is the distance of the insertion portion 31 in the longitudinal direction X between the free end remote from the projection 32 and the base near the projection 32, i.e. the distance between the projection of the maximum dimension point and the minimum dimension point of the insertion portion 31 in the longitudinal direction X (see fig. 5); h is the height of the insertion portion 31, e.g. the vertical dimension in the vertical direction perpendicular to the longitudinal direction X; and μ is the coefficient of friction between the first bead 10 and the pressure resistant member 30, for example, for the surface on the left side of the insertion portion 31, the coefficient of friction between the inclined surface of the second end 12 of the first bead 10 and the inclined surface on the left side of the pressure resistant member 30.

Likewise, for the right-hand inclined surface of the insertion portion 31 shown in FIG. 5, the slope thereof may also satisfy l/h < μ, where μ is the coefficient of friction between the inclined surface of the first end 21 of the second rim 20 and the right-hand inclined surface of the pressure resisting member 30.

Preferably, the height h of the insert 31 is greater than the depth of the gap between the first and

second flanges

10, 20 so as to be a full insertion fit into the gap and still ensure a tight engagement with the ends of the first and

second flanges

10, 20 when the gap is greater than desired. However, it will be appreciated that in any event, it is preferable to insert the insert 31 at least at 1/2 of the height of the void to ensure that the insert 31 can be reliably engaged in the void.

The inventors have discovered that when the area of the compression resistant member 30 that conforms to the end of the first or

second flanges

10, 20 is greater than 2/3 of the end face area of the end of the first or

second flanges

10, 20, the compression resistant member 30 can be unexpectedly retained in the gap between the first and

second flanges

10, 20 without escaping from the gap due to the compressive load between the first and

second flanges

10, 20.

In an alternative embodiment shown in fig. 6, the pressure resistant member 30 may further comprise a pin hole 33 provided near the insertion portion 31, the pin hole 33 being adapted to cooperate with a pin, not shown, so that after the pressure resistant member 30 is insert-fitted into the void, the pressure resistant member 30 is firmly held in the void by the pin so as not to accidentally fall out of the void. The pin hole 33 may be a through hole or a threaded hole and may be circular or other shapes without departing from the scope of the present invention.

As a non-limiting example of the present invention and as a preferred embodiment, the protrusion 32 may be provided at the top of the compression resistance 30, for example extending away from the compression resistance 30 in the longitudinal direction X toward the first and

second flanges

10 and 20, respectively, forming a boss or nose form. The projection 32 functions as a stopper member, and when the clearance is too large, the projection 32 functions to prevent the compression resistance member 30 from falling into the clearance or falling out of the clearance.

It should be appreciated that the compression resistant member 30 may be made of any material by any machining method, and preferably the compression resistant member 30 is made of the same material as the first or

second flanges

10, 20, such as an aluminum alloy, a titanium alloy, or a composite material.

With continued reference back to FIGS. 1-3, as shown, the attachment structure 40 may include a strap 41 and a fastener 42, with the attachment structure 30 serving to securely hold the first and

second flanges

10, 20 together.

As a non-limiting example of the present invention and as a preferred embodiment, the first and

second flanges

10 and 20 may be provided with a first series of openings 13 and a second series of openings 23, respectively, while the strap 41 includes attachable holes 411 for attaching the first flange 10 to the second flange 20, such as at the ends of the first and

second flanges

10 and 20, by way of fasteners 42 passing through the openings and attachment holes.

In the embodiment shown in the figures, the first series of openings 13 comprises 3 circular openings close to the second end 12, while the second series of openings 23 likewise comprises 3 circular openings close to the first end 21, while the strap 41 comprises 6 attachment holes 411. In addition, lap plates 31 are shown as comprising 2 and gripping them from both sides of the first and

second flanges

10, 20 to hold them firmly together while avoiding lateral shifting of the compression resistance elements 30 in the voids.

The fasteners 42 may be any bolts, studs, etc. known in the art, but preferably include shear bolts 421 and cooperating nuts 422 to cooperate with the compression members 30 to withstand large compressive loads between the keel beams, or to withstand small tensile loads alone.

It should be understood that the number and form of the straps 41 and the openings or apertures are merely illustrative and that a person skilled in the art may envision other numbers or types of connection structures, such as crimping structures, snap-engagement structures, etc., without departing from the scope of the invention.

Fig. 7 is a schematic view illustrating a method of installing the keel beam flange connection structure 100 according to a non-limiting embodiment of the present invention.

As schematically shown in the figure, the method may comprise the steps of:

(1) an alignment step in which the first and

second flanges

10, 20 are aligned in the longitudinal direction X, specifically, for example, such that the second end 12 of the first flange 10 and the first end 21 of the second flange 20 are aligned up and down and right and left.

(2) A step of placing a pressure-resistant member, in which the pressure-resistant member 30 is placed between the gaps of the ends of the first and

second flanges

10, 20 that are close to each other; preferably, the step of placing the compression resistant member may further include a grinding step in which the side of the insert 31 of the compression resistant member 30 may be ground, for example, by means of a grinder/grinding wheel or the like, until the side of the insert 31 abuts the end of the first bead 10 or the second bead 20 over an area 2/3 greater than the area of the end face of the end of the first bead 10 or the second bead 20.

(3) A securing step in which the first bead 10 is attached to the second bead 20 by means of the attachment structure 40. For example, the strap 41 is clamped on both sides to the first and

second flanges

10, 20 and the clamping is tightened by means of shear bolts 421 passing through openings therein and cooperating nuts 422.

At this time, if there is no desired opening on the first bead 10, the second bead 20, and/or the lap plate 41, a drilling step may be further included in the fixing step.

It should be understood that the above installation steps are illustrative, and one skilled in the art may add or subtract one or more steps as appropriate, and may adjust the order between the steps. For example, the drilling may be performed in a fixing step, or in a previous alignment step, without departing from the scope of the inventive concept.

As used herein, the terms "first" or "second", etc., used to indicate a sequence, are only for the purpose of making the concept of the present invention shown in the form of preferred embodiments better understood by those of ordinary skill in the art, and are not intended to limit the present invention. Unless otherwise specified, all sequences, orientations, or orientations are used for the purpose of distinguishing one element/component/structure from another element/component/structure only, and do not imply any particular sequence, order of installation, direction, or orientation, unless otherwise specified. For example, in an alternative embodiment, "first bead" may be used to represent "second bead," and "left side surface" may alternatively be "right side surface," or the like.

In summary, the keel beam edge strip connection structure 100 according to the embodiment of the invention overcomes the disadvantages of the prior art and achieves the intended purpose.

Although the keel beam flange connection structure of the present invention has been described above in connection with the preferred embodiment, it will be appreciated by those skilled in the art that the above examples are intended to be illustrative only and not to be construed as limiting the invention. Therefore, various modifications and changes can be made to the present invention within the spirit and scope of the claims, and these modifications and changes will fall within the scope of the claims of the present invention.

Claims

1. A keel beam edge connection structure (100), said keel beam edge connection structure (100) comprising:

a first bead (10) and a second bead (20) aligned in a longitudinal direction (X);

a compression resistance (30) engaged between the interstices of the mutually close ends of the first and second flanges (10, 20); and

an attachment structure (40), the attachment structure 30 for holding the first bead (10) and the second bead (20) together.

2. Keel beam and rim connection structure (100) according to claim 1, wherein said gap between the ends of said first rim (10) and said second rim (20) is V-shaped, while said compression resistance element (30) is a wedge-shaped pad and has an insertion portion (31) tapering towards the tip.

3. Keel rail connection structure (100) according to claim 2, wherein said compression resistance (30) is provided with a projection (32) extending in said longitudinal direction (X) towards said first and second rail (10, 20) and away from said compression resistance (30).

4. Keel rail connection structure (100) according to claim 3, wherein the inclination of the inclined surface of the insertion portion (31) of the compression resistance (30) satisfies l/h < μ, wherein l is the distance in the longitudinal direction (X) between the free end distal from the protrusion (32) and the base proximal to the protrusion (32) on the side of the insertion portion (31), h is the height of the insertion portion (31), and wherein μ is the coefficient of friction between the first or second rail (10, 20) and the compression resistance (30).

5. The keel beam edge connection structure (100) of claim 4, wherein the compression resistance element (30) has a greater area of abutment with the end of the first or second edge (10, 20) than 2/3 of the area of the end face of the end of the first or second edge (10, 20).

6. The keel beam flange connection structure (100) according to any one of claims 1-5, wherein said attachment structure (40) comprises a strap (41) and a fastener (42) for securing the strap to the first and second flanges (10, 20).

7. The keel beam and flange connection structure (100) according to claim 6, wherein said lap plates (31) comprise 2, and said first flange (10) is attached to said second flange (20) by means of said fasteners (42) at both sides of the ends of said first flange (10) and said second flange (20), respectively.

8. The keel beam edge connection structure (100) according to claim 7, wherein said fastener (42) comprises a shear bolt (421) and a cooperating nut (422).

9. A method of installing a keel beam edge strip connection structure (100) according to any one of claims 1-8, said method comprising the steps of:

(1) an alignment step in which the first bead (10) and the second bead (20) are aligned in the longitudinal direction (X);

(2) a compression element placing step, in which the compression element (30) is placed between the gaps of the ends of the first bead (10) and the second bead (20) that are close to each other; and

(3) a fixing step in which the first bead (10) is attached to the second bead (20) by means of the attachment structure (40).

10. The method of claim 9, wherein the step of placing a compression resistance element further comprises a grinding step in which the sides of the insert portion (31) of the compression resistance element (30) are ground until the side of the insert portion (31) conforms to the end of the first bead (10) or the second bead (20) in an area greater than 2/3 of the area of the end face of the end of the first bead (10) or the second bead (20).