JP2012245895A - Shock absorbing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorbing structure in which a material, such as an aluminum honeycomb, which is superior in impact energy absorbing capacity to impact in a main axis direction but not superior in impact energy absorbing capacity to impact in a shear direction, is used to obtain a shock-absorbing effect favorable also for oblique collision.SOLUTION: In the shock absorbing structure, an impact energy absorbing member is arranged in a space configured with an inner wall under a floor of an airframe of an aircraft and an outer wall of the aircraft, and energy when the airframe receives impact from the outside is absorbed by the impact energy absorbing member. A protrusion is attached to the outside of the outer wall and further on a tip side of the airframe than a joint between the outer wall and the energy absorbing member.

Description

  The present invention relates to an impact absorbing structure for an aircraft fuselage.

  Taking an aircraft or ship as an example, an energy absorbing member made of fiber reinforced plastic (FRP) that relaxes the impact force from the outside by its own compression failure when they collide with another body at the tip of the aircraft or ship. In the following Patent Document 1, it is proposed that the front end portion is provided so as to face the impact force loading direction.

JP-A-7-224875

  Now, taking the case where the aircraft collides obliquely with the ground as an example, as a shock absorbing structure that absorbs the shock received by the airframe, the airframe is provided with an impact absorbing structure as shown in FIG. Suppose that In this impact absorbing structure, an impact energy absorbing member 14 for absorbing impact energy of an oblique collision with the ground 12 is attached to the inner wall of a plate-like airframe schematically shown as 10 in FIG. 14 is covered with an outer wall 16, and the end 22 of the extended portion 20 of the outer wall 16 in front of the edge 18 of the impact energy absorbing member 14 is fixed to the inner wall 10. In this way, the impact energy absorbing member 14 is attached to the inner wall 10, and this is covered with the outer wall 16, and the extended portion 20 of the outer wall 16 in front of the edge 18 of the impact energy absorbing member 14 is connected to the edge of the impact energy absorbing member 14. If the end 22 is fixed to the inner wall 10 and an appropriate tension is applied to the outer wall 16, the extension portion 20 functions as a tension spring, and the impact energy absorbing member 14 is moved to the inner wall. 10 can be attached to the body in a stable and stable state, but in this case, in order to function the extension portion 20 of the outer wall obliquely and function as a tension spring, As shown in the figure, a space portion 26 having a triangular cross section or a shape close to that is formed.

  However, in the shock absorbing structure as described above, when the airframe collides obliquely with another body such as the ground 12, the shock energy absorbing member 14 starts from the edge 18 as shown in FIG. Since the outer wall 16 is sandwiched between the outer body 16 and the other body such as the ground 12, the impact energy absorbing member 14 is moved along the surface in the direction of the arrow Q while being strongly pressed against the surface of the other body. The edge portion 18 is crushed in the thickness direction and simultaneously pushed in the direction opposite to the arrow Q, and the impact energy absorbing member 14 is subjected to shear deformation. As a material that is light and has a high impact energy absorption capability and is suitable for constituting the impact energy absorption member 14, there is a material such as an aluminum honeycomb, for example. Such a material exhibits a high impact energy absorption capability. This is when the impact acts in the direction of the main shaft, and the impact energy absorption capacity for the impact in the shear direction is greatly inferior to that. Therefore, in the impact absorbing structure as shown in FIG. 4, when the impact energy absorbing member 14 is made of a material such as an aluminum honeycomb, a shearing action is caused by an oblique collision as shown in FIG. 4B. When receiving, there exists a problem that a favorable impact-absorbing effect cannot be obtained.

  The present invention pays attention to the above situation in the shock absorbing structure as shown in FIG. 4 and, like an aluminum honeycomb, has an excellent shock energy absorbing ability for the impact in the main axis direction, but absorbs the shock energy for the shock in the shear direction. Even when an impact absorbing structure such as that shown in FIG. 4 is configured using a material that cannot be said to be superior in performance, a good impact can be obtained in an oblique collision as shown in FIG. 4B. An object of the present invention is to provide an impact absorbing structure capable of obtaining an absorbing action.

In order to solve the above-mentioned problems, the present invention is arranged in a space constituted by an inner wall under the floor of an aircraft body and an outer wall of the aircraft, and the energy when the body receives an impact from the outside. An energy absorbing member to absorb,
Proposing an impact absorbing structure comprising: a projection attached outside the outer wall and on a front end side of the airframe with respect to a coupling portion between the outer wall and the energy absorbing member. is there.

  In the above-described shock absorbing structure, the protrusion may be disposed so as to face the outside of the outer wall with a space formed by the inner wall, the outer wall, and the energy absorbing member as a back. In this case, when the airframe collides with another body, the outer wall may be deformed to the inside of the space portion by the collision between the protrusion and the other body.

  In the above shock absorbing structure, the protrusion may be arranged to face the lower front side of the aircraft.

  As described above, the aircraft is disposed in a space formed by the inner wall under the floor of the fuselage and the outer wall of the fuselage, and the energy absorbing member absorbs energy when the fuselage receives an external impact. If the shock absorbing structure is provided on the outer side of the outer wall and on the front end side of the airframe with respect to the connecting portion between the outer wall and the energy absorbing member, the shock absorbing structure is provided. In parallel with the structure, the impact energy absorbing member collides obliquely with the other body from the front edge portion of the impact energy absorbing member, and the impact energy absorbing member starts from the front edge portion and is gradually pressed more strongly against the other body. Since the projecting end contacts the other body and gradually deforms the forward extension portion of the outer wall to the inside gradually, it is suppressed that the front edge portion of the impact energy absorbing member shifts backward with respect to the inner wall, Shock Front edge of the conservation absorbing member is simply compressed, spared from exposure to shear loads.

  When the impact energy absorbing member starts from its front edge and is gradually squeezed more and more, the projecting portion acts as a slack in the front extending portion of the outer wall. This action is to cancel the slack by deforming to the side, so that the projecting part is installed so that the space part composed of the inner wall, the outer wall, and the energy absorbing member is facing away from the outer wall. If done, it is most effectively achieved. According to this structure, when the airframe collides with another body, the outer wall is deformed into the space due to the collision between the projection and the other body. Further, if the projection is arranged so as to face the lower front side of the fuselage, the impact energy absorbing member in the shock absorbing structure can be accurately operated when the aircraft strikes the ground obliquely from the front end of the fuselage. Can do.

The cross-sectional view similar to FIG. 4 which shows the 1st Example of the impact-absorbing structure by this invention. The cross section similar to FIG. 1 which shows the 2nd Example of the impact-absorbing structure by this invention. The cross-sectional view similar to FIG. 1 or 2 which shows the 3rd Example of the impact-absorbing structure by this invention. 1 is a cross-sectional view showing a shock absorbing structure that is a basis of the shock absorbing structure according to the present invention and is considered within the scope of the prior art.

  In FIG. 1 showing the first embodiment of the shock absorbing structure according to the present invention, the parts corresponding to the respective parts in the structure shown in FIG. 4 are given the same reference numerals as those in FIG. These parts operate in the same manner as the parts in FIG. 4 except for some changes in function caused by the addition of the protrusions 28 according to the present invention. Therefore, the basic description of each of these parts is based on the description given with reference to FIG. 4, and the same description is not repeated to avoid redundancy of the specification.

  In the embodiment shown in FIG. 1, it extends in the center of the extending portion 20 of the outer wall 16 in front of the edge 18 of the impact energy absorbing member 14 in a direction perpendicular to the cross section and perpendicular to the drawing sheet. A band-like projection 28 is attached at the base, and when the shock absorbing structure strikes the other body 12 at an angle, it comes into contact with the other body at the projecting end, and to the root by the other body. As it is pushed, the extending portion 20 of the outer wall 16 is deformed into an inverted V shape when viewed in a cross section into the space portion 26. In this case, the height of the protrusion 28 is based on the design of the impact absorbing structure, particularly the thickness a of the impact energy absorbing member 14 and the distance b between the edge 24 of the impact energy absorbing member 14 and the end 22 of the outer wall 16. Thus, when the shock absorbing structure is obliquely pressed against the other body 12 and the shock energy absorbing member 14 starts to reduce its thickness starting from the edge 18, What is necessary is just to make it the height which the slack which arises in the extension part 20 of an outer wall by the deformation | transformation with respect to the inner wall 10 is canceled. At this time, if the projection 28 comes into contact with the other body 12 and is pushed to the space portion 26 together with the extending portion 20 of the outer wall 16, the projection portion 28 is impacted. The impact absorbing action of the energy absorbing member 14 is not disturbed. Of course, the angle at which the shock absorbing structure travels obliquely with respect to the other body 12 is not determined, but the above-described collision with the shock absorbing structure against the other body 12 due to the traveling angle within a roughly expected range is described above. The height of the projecting portion 28 only needs to be determined so that the extension portion slack canceling action can be accurately obtained.

  FIG. 1 shows the moment when the oblique collision of the shock absorbing structure to the other body 12 has progressed somewhat, and a part of the figure shows the extension 20 of the outer wall in the shock absorbing structure before contact and The initial position of the attached protrusion 28 is indicated by a virtual line. In the illustrated embodiment, the base of the protrusion 28 is such that when the protrusion 28 deforms the extended portion 20 of the outer wall 16 into the space portion 26 in a cross-section and is inverted V-shaped, It is attached to the extended part 20 of the outer wall at a position facing the innermost part 30 of the part, and the slackness of the extended part 20 can be canceled to the largest value.

  In FIG. 2 showing the second embodiment of the shock absorbing structure according to the present invention, the parts corresponding to the respective parts in the structure shown in FIG. 4 are given the same reference numerals as in FIG. The repetition of the same description for each part will be omitted for the same reason as described for the embodiment of FIG.

  In the embodiment shown in FIG. 2, in the central portion of the extending portion 20 of the outer wall 16 in front of the edge 18 of the impact energy absorbing member 14, the bottom surface is flat and the top portion is arc-shaped in cross section. A projection 32 extending perpendicularly to the plane of the drawing and attached in the direction perpendicular to the plane of the drawing is mounted on the flat bottom surface, and the projection 32 crosses the extension 20 of the outer wall 16 into the space 26 in a cross section. As seen, it is deformed into a mountain shape having a flat top at the center. Also in this case, the height of the protrusion 32 is the same as the design of the shock absorbing structure, particularly the thickness a of the shock energy absorbing member 14 described with reference to FIG. 1 and the edge 24 of the shock energy absorbing member 14 to the end 22 of the outer wall 16. Based on the distance b between them, when the shock absorbing structure strikes the other body 12 at an angle and the shock energy absorbing member 14 reduces its thickness starting from the portion of the edge 18, it contacts the other body 12 at the tip. What is necessary is just to make it the height which cancels the slack which arises in the extension part 20 of an outer wall by the deformation | transformation with respect to the inner wall 10 of the protrusion part 32 which contact | connected. Also in this case, the dimensional design of the projecting portion 32 is such that the extension portion slack canceling action is accurately performed against the collision of the shock absorbing structure with the other body 12 due to the traveling angle within a roughly expected range. If the protrusion 32 collides with the other body 12 and is pushed toward the space portion 26 together with the extending portion 20 of the outer wall 16, the size of the protrusion 32 can be accommodated in the space portion. The protrusion 32 does not interfere with the impact absorbing function of the impact energy absorbing member 14.

  FIG. 2 also shows the moment when the oblique collision of the shock absorbing structure to the other body 12 has progressed somewhat, and a part of the figure includes an extension portion 20 of the outer wall in the shock absorbing structure before the collision. The initial position of the protrusion 32 attached thereto is indicated by a virtual line. In this embodiment, since the protrusion 32 may be fixed to the outer wall over the entire area of a relatively wide flat bottom surface, the protrusion can be easily attached to the outer wall, and the stability of the attachment state is increased.

  In FIG. 3 showing the third embodiment of the shock absorbing structure according to the present invention, the portions corresponding to the respective parts in the structure shown in FIG. 4 are given the same reference numerals as in FIG. The repetition of the same description for each part will be omitted for the same reason as described for the embodiment of FIG.

  In the embodiment shown in FIG. 3, the bottom surface and the top of the extending portion 20 of the outer wall 16 in front of the edge 18 of the impact energy absorbing member 14 are arcuate in the cross section and perpendicular to the cross section. A soot projection 34 extending in a direction perpendicular to the paper surface of the figure is attached along the center 36 of the arc-shaped bottom surface, and the projection 34 extends the extension 20 of the outer wall 16 into the space 26. When viewed in cross section, it is deformed into a mountain shape having an arcuate top at the center. In this case as well, the height of the protrusion 34 depends on the design of the shock absorbing structure, particularly the thickness a of the shock energy absorbing member 14 described with reference to FIG. 1 and the end edge 24 of the shock energy absorbing member 14 to the end 22 of the outer wall 16. Based on the distance b between them, when the shock absorbing structure strikes the other body 12 at an angle and the shock energy absorbing member 14 reduces its thickness starting from the portion of the edge 18, it contacts the other body 12 at the tip. The height of the protruding portion 34 may be set so as to cancel the slackness generated in the extending portion 20 of the outer wall due to the deformation of the protruding portion 34 with respect to the inner wall 10. As long as it is set to fit within the space when pushed together with 20 into the space 26, the projection 34 does not hinder the impact absorbing function of the impact energy absorbing member 14.

  FIG. 3 also shows a moment when the oblique collision of the shock absorbing structure to the other body 12 has progressed somewhat, and a part of the figure includes an extension portion 20 of the outer wall in the shock absorbing structure before contact. The initial position of the protrusion 34 attached thereto is indicated by a virtual line. In this case as well, the dimensional design of the protrusion 34 is such that the extension portion slack canceling action is accurately performed against the collision of the shock absorbing structure with the other body 12 due to the traveling angle within a roughly expected range. What is necessary is just to be determined so that it may be obtained. In this embodiment, when the projecting portion 34 deforms the extending portion 20 of the outer wall into the space portion 26, the projecting portion 34 is smoothly curved without being bent in the middle of the extending portion 20 of the outer wall. It is possible to more reliably eliminate the fear that the existing portion 20 may be broken.

  While the present invention has been described in detail with respect to several embodiments thereof, it will be apparent to those skilled in the art that various modifications can be made to these embodiments within the scope of the present invention. .

  DESCRIPTION OF SYMBOLS 10 ... Inner wall, 12 ... Other body, 14 ... Impact energy absorption member, 16 ... Outer wall, 18 ... Edge of impact energy absorption member, 20 ... Extension part of outer wall, 22 ... Termination of outer wall extension part, 24 ... Impact energy Edge of absorbing member, 26 ... space, 28 ... projection, 30 ... innermost part of space, 32, 34 ... projection, 36 ... center of arc-shaped bottom surface of projection 34

Claims (4)

An energy absorbing member disposed in a space formed by an inner wall under the floor of an aircraft fuselage and an outer wall of the aircraft, and absorbing energy when the aircraft is subjected to an external impact;
An impact absorbing structure comprising: a protrusion attached outside the outer wall and closer to the distal end side of the airframe than a coupling portion between the outer wall and the energy absorbing member.   2. The shock absorption according to claim 1, wherein the protrusion is installed so as to face the outside of the outer wall with a space formed by the inner wall, the outer wall, and the energy absorbing member as a back. Construction.   3. The shock absorbing structure according to claim 2, wherein when the airframe collides with another body, the outer wall is deformed to the inside of the space portion by the collision between the protrusion and the other body.   The impact-absorbing structure according to any one of claims 1 to 3, wherein the protrusion is disposed so as to face a lower front side of the body.

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