RU2269393C2 - Honeycomb filler producing method - Google Patents

Abstract

FIELD: aircraft manufacture, namely projection of reduced-mass structures served for noise absorption.

SUBSTANCE: method comprises steps of cutting material for forming cross rows with notches along broken line. Said notches are different in odd and even rows. Then material is bent relative to lengthwise axis and it is crosswise bent for forming honeycomb block. Lines of notches and cross bending in even and odd rows are equidistant and pitch between them is constant.

EFFECT: lowered cost of honeycomb block due to waste free cutting out of material.

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Description

The invention relates to the field of designing structures to reduce the weight of the product and ensure noise absorption, and can be used in many industries, in particular in aircraft construction.

Currently, in aircraft, along with the existing stringer and monolithic panels, three-layer structures with honeycomb filler are used as power and non-power elements of the airframe.

Methods of manufacturing a honeycomb core are known. So, in the description to A.S. SU No. 1222368, class In 21 D 47/00, a method is presented that includes stitching rows of notches arranged in a checkerboard pattern, corrugating the material in the form of half cells of honeycombs, applying a binder to the strip material from two sides, bending it along the cut lines “into an accordion” to form a honeycomb block and fixing the binder. The strip material is arranged in two layers, making cuts, corrugation and bending of two layers simultaneously. The closest solution to the claimed m is the solution given in the description to A. with. SU No. 415177, class B 32 V 31/16. The method includes the operation of cutting material with the formation of the applied rows, in which the incisions are staggered, the operation of bending the material relative to the longitudinal axis with the formation of half-cell profiles and transverse bending "accordion" along the notches. In the profile direction, each incision is made along a broken line. The step between the incisions is performed by a variable changing through an even number of rows.

This sequence and the nature of the incisions provide a honeycomb, the axis of the cells of which are perpendicular to the horizontal plane. The resulting honeycomb in combination with two skins, one of which is perforated, is used in aircraft construction as a sound-absorbing structure.

It is known that the effect of sound attenuation increases if the cell walls are not located vertically, but at an angle to the skin. Honeycombs with sloping cell walls are obtained by cutting the surfaces of the honeycomb at an angle on both sides with a sufficient height, which leads to large waste.

The objective of the invention is to obtain a honeycomb from a sheet with inclined walls relative to the skin.

The problem is solved due to the fact that in the known method, which includes operations: cutting the material with the formation of transverse rows in which cuts are made along the broken line, the nature of which is different in even and odd rows, the bending of the material relative to the longitudinal axis and transverse bending accordion ”to the formation of a honeycomb, in the proposed method, the lines of incisions and transverse bending in the aggregate of even and odd rows are performed equidistant, and the step between the rows is constant.

Compliance with the conditions - the equidistance of the notch and bend lines in the aggregate in even and odd rows, the step between which is constant, ensures the production of honeycombs with inclined machines. With an unstable step, the parallelism of the end surfaces of the honeycomb changes.

In case of violation of the equidistance of the lines of cuts and bending in the rows, the flatness of the end surfaces of the honeycomb is broken.

The technical result of the invention is to reduce the cost of the resulting honeycomb core due to non-waste cutting.

Figure 1 shows a strip of material in plan with lines of longitudinal and transverse folds.

Figure 2 is the same with the profile shown in the process of adding cells.

Figure 3 shows the calculated parameters of the inclined cell.

The strip material for the honeycomb core may be steels and alloys joined by welding or soldering, or other materials joined to the skin by binders, in particular glue. To obtain a honeycomb, the initial data are set: the bandwidth, the nature of the cell, the distance between its faces, the required angle of inclination of the honeycomb and the height of the cells.

The manufacturing process of the honeycomb includes cutting the material with the marking of the transverse rows and lines of longitudinal folds. Set the step between the rows, which is determined by calculation and keep it constant between the rows. By marking determine the nature of the broken line, i.e. determine the value "C" of the displacement of the notches relative to the transverse folds. A cut is made in the even and odd rows, while the cuts in these rows are shifted by a. The lines of cuts and bends in the aggregate in even and odd rows are equidistant. The incised material is corrugated in the transverse direction, and then folded into an “accordion”, bending it along the notch lines with the formation of a honeycomb structure.

An example of a specific implementation. To obtain an inclined honeycomb, the initial data are given (Figs. 1, 2, 3):

- honeycomb regular hexagonal shape;

- the distance between the faces of the cells - 20 mm;

- cell height - 20 mm;

- the angle of inclination of cells - 60 °.

Determine the offset of the notches relative to the transverse folds "c" of Δ ABA (figure 2)

Determine the step between the notches on the sheet "t" from Δ ABC (figure 2)

The step between the cuts is constant.

On the blank sheet (if necessary, previously perforated), marking is made on the basis of the obtained calculations (s, t). Lines of longitudinal folds are applied at a distance equal to the distance between the faces of the honeycomb - 20 mm (figure 2).

An incision is made on the lines of transverse folds and the material is corrugated in this direction, folded into an “accordion”, bending it along the notch lines with the formation of a honeycomb structure.

The lines of incisions and transverse bending are collectively equidistant in all rows.

The application of the proposed method allows to obtain inclined honeycomb used as an element of sound attenuation, waste-free, which reduces the cost of manufacturing products.

Claims (1)

A method of manufacturing a honeycomb core from sheet material, including cutting the material with the formation of transverse rows, in which cuts along the broken line are performed, the nature of which is different in even and odd rows, bending the material relative to the longitudinal axis and transverse bending into an "accordion" before formation sotoblock, characterized in that the lines of incisions and transverse bending in the aggregate in even and odd rows are performed equidistant, and the step between the rows is constant.

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