RU2445207C1 - Mandrel for making articles from composite materials - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of parts from composite materials, namely, power plant shells, mainly, solid propellant engine nozzle unit parts. Proposed mandrel comprises forming section made up of truncated cone, cover and flange jointed to small and large faces of said forming section, respectively. Note here that flange is secured to detachable spring and pressure rings that embrace forming section and circular clearance. Chamber formed between spring ring inner surface and forming section outer surface communicates via section hole with unions arranged inside mandrel, said unions being furnished with shutoff valve. Note here that cover is jointed with ring embracing its peripheral surface, ring outer surface extending beyond forming section edges to make a ledge in joint zone.

EFFECT: higher quality of products, ease of hardened material carcass withdrawal from mandrel.

3 cl, 6 dwg

Description

The invention relates to the technology of manufacturing parts from composite materials (CM), namely shells for power structures, mainly parts of nozzle blocks of rocket engines for solid fuel (solid propellant rocket engines).

In the manufacture of parts from KM, the starting material frame is mounted on a forming mandrel for impregnation with a binder and subsequent curing in a hydroclave.

A known mandrel for the manufacture of products from composite materials containing a forming part made in the form of a hollow truncated cone, a cover and a flange connected, respectively, to the small and large ends of the forming part (see, for example, I.M. Bulanov, V.V. . Sparrow. Technology of rocket and aerospace structures from composite materials. - M.: Publishing House of MSTU named after NE Bauman, 1998 - pp. 197, 446, 449, 452) - the closest analogue.

The known design of the mandrel allows you to create a package of KM laying out or winding on the mandrel of the source material for impregnation with a binder in an impregnation machine and subsequent curing in a hydroclave.

However, the known design of the mandrel does not allow to provide the required quality of manufacturing products from composite materials in a hydroclave with an elastic diaphragm.

So, when impregnating the skeleton of the starting material in a hydroclave with an elastic diaphragm filled with a binder, it is impossible to ensure that the excess binder is removed from the cavity between the mandrel and the elastic diaphragm during the impregnation process.

Also, during curing of the starting material frame on such a mandrel in a hydroclave with an elastic diaphragm, it is difficult to fully remove the volatiles from the framework located in the cavity between the mandrel and the elastic diaphragm.

In addition, it is difficult to remove the workpiece from the forming part of the mandrel after curing of the frame, since, despite the use of various types of release coatings, the adhesion of the frame to the mandrel can be significant, especially in the manufacture of RDTT sockets, which cure under the influence of elevated temperature and pressure.

When removing the cured frame from the mandrel, partial destruction of the frame, for example, from impact, is possible, which is not permissible.

Thus, the known design of the mandrel is practically not applicable for the manufacture of products from composite materials in a hydroclave with an elastic diaphragm.

The technical task of this invention is to develop the design of the mandrel, which allows to provide the required quality of manufacturing products from composite materials in a hydroclave with an elastic diaphragm.

The technical result is achieved in that in the mandrel for the manufacture of products from composite materials containing a forming part made in the form of a hollow truncated cone, a cover and a flange connected, respectively, to the small and large ends of the forming part, the flange is fastened with removable squeezing and clamping rings covering the forming part with an annular gap, wherein the cavity formed between the inner surface of the squeezing ring and the outer surface of the forming part is communicated through holes made in its wall, with fittings placed inside the mandrel equipped with a shut-off valve, the lid being fastened to a ring covering its peripheral surface, the outer surface of which extends beyond the contour of the forming part, forming a ledge in the junction zone with it.

In addition, a series of through threaded holes are made in the squeeze ring for screwing the process screws all the way into the flange when removing the workpiece from the mandrel.

The squeeze ring is fastened to the flange with bolts, the heads of which are covered by a pressure ring, fastened to the squeeze ring by bolts, the heads of which, in turn, are covered by an additional ring, which are secured to the squeeze ring by countersunk screws.

The cover is fastened with a ring covering its peripheral surface with bolts, the heads of which are covered by a second ring, which are fastened to the first ring with countersunk screws.

The presence of a removable clamping ring allows you to securely fasten the frame of the material at the mandrel flange.

The presence of a removable squeeze ring, fastened to the flange when installing the material frame and detachable from the flange before removing the frame from the mandrel, allows the interaction of the squeeze ring with the flange to facilitate removal of the frame from the mandrel.

The installation of the clamping and squeezing rings with an annular gap relative to the forming part of the mandrel allows for reliable pinching by the clamping ring of the end of the material frame in the gap, as well as creating a cavity between the forming part and the squeezing ring for the accumulation and subsequent removal of excess binder during impregnation or for the accumulation and subsequent removal of volatile substances formed during curing.

The communication of the cavity formed by the inner surface of the squeezing ring and the outer surface of the forming part through openings made in the wall of the forming part with fittings located inside the mandrel allows simple and reliable removal of volatiles from the KM carcass during curing and the removal of excess binder during the carcass impregnation in the hydroclave.

Providing the fittings with a shut-off valve allows you to regulate the process of removing volatiles from the KM frame during curing and removing excess binder when the frame is impregnated in the hydroclave, opening or closing the valve at the right time.

The fastening of the cover with a ring covering its peripheral surface, the outer surface of which extends beyond the contour of the forming part, forming a ledge in the junction zone with it, allows for reliable fixing of the frame at the mandrel cover.

The execution of a series of threaded threaded holes in the squeeze ring for screwing the screws all the way into the flange when removing the material frame from the mandrel allows you to most easily move the squeeze ring from the flange after removing the clamping ring and, accordingly, separate the frame from the forming part of the mandrel without applying shock loads, which eliminates the possibility of violating the integrity of the frame.

The fastening of the squeezing ring with the flange by bolts, the heads of which are covered by a clamping ring, fastened with the squeezing ring by bolts, the heads of which, in turn, are covered by an additional ring, which are secured to the squeezing ring by screws with countersunk heads, allows to close the holes for the bolt heads and to prevent unacceptable pressing in by elastic diaphragms in these areas under the influence of the pressure of the working medium when the frame is impregnated or cured.

The fastening of the cover with a ring covering its peripheral surface with bolts, the heads of which are covered by a second ring fastening to the first ring with countersunk screws, also allows you to close the holes for the bolt heads and exclude unacceptable indentation of the elastic diaphragm in these areas under the influence of the working medium pressure during impregnation or curing frame.

Figure 1 shows a diagram of the mandrel assembly.

Figure 2 shows a diagram of the withdrawal of excess binder or volatile.

Figure 3 shows a diagram of the interaction of the squeeze ring with the flange.

The mandrel for manufacturing products from composite materials contains a forming part 1 made in the form of a hollow truncated cone, a flange 2, and a cover 3.

The flange 2 is connected to the large end of the forming part 1 by bolts 4, and the cover 3 is connected to the small end of the forming part 1 by bolts 5.

The mandrel is equipped with a removable squeeze ring 6 and a removable clamp ring 7, fastened to the flange 2, while the rings 6 and 7 cover the forming part 1 with an annular gap D.

The cavity formed between the inner surface of the squeezing ring 6 and the outer surface of the forming part 1 is communicated through openings 8 made in the wall of the forming part 1 (Fig. 2), with two diametrically opposed fittings 9 located inside the mandrel, each of which is equipped with a shut-off valve 10.

A ring 11 is bonded to the cover 3 and encloses its peripheral surface 11, the outer surface of which extends beyond the contour of the forming part 1, forming a step E.

The squeezing ring 6 is fastened with a flange 2 by bolts 12, the heads of which are covered by a clamping ring 7, fastened with a squeezing ring 6 by bolts 13, the heads of which, in turn, are covered by an additional ring 14 attached to the clamping ring 7 by screws 15 with countersunk heads.

In the squeezing ring 6, a series of through threaded holes are made for screwing the process screws 16 all the way into the flange 2 when removing the workpiece from the mandrel (Fig. 3).

Ring 11, similar to fastening the clamping ring 7 to the squeezing ring 6, is fastened to the cover 3 by bolts (not shown in Fig.), The heads of which, like the heads of the bolts 5 of the fastening of the cover 3 to the forming part 1, are covered by a ring 17 attached to the ring 11 countersunk head screws 18.

When preparing the mandrel for work on the forming part 1 with a fixed flange 2, a pre-cut frame of the source material made by flashing coal fabric of the URAL-TM-4-22 type (not shown) is installed.

Set the squeeze ring 6, the clamping ring 7 and the additional ring 12, securing the material frame on the forming part 1 at the flange 2.

Then install the cover 3, the ring 11 and the ring 17, finally fixing the frame of the material on the forming part 1.

After that, a container for collecting a binder is placed in the cavity of the mandrel, the container is connected to the fittings 9 with acetylene hoses (not shown).

The mandrel prepared in this way is ready for use, both when impregnating the starting material skeleton in a hydroclave with an elastic diaphragm filled with a binder, in this case, excess binder is removed into the tank during the impregnation process, and when the material impregnated with a binder is cured in a hydroclave with an elastic diaphragm, In this case, from the cavity between the mandrel and the elastic diaphragm through openings 8 in the wall of the forming part 1 of the mandrel, connected with the fittings 9, the volatiles formed during the curing are removed tions.

After the binder is impregnated or after curing, the composite material frame is removed from the forming part 1 of the mandrel, while the mandrel is partially disassembled before removal, including removing the ring 11, removing the stop E, unfasten the clamping ring 7 from the squeezing ring 6 and disconnect the squeezing ring 6 from flange 2 by unscrewing bolts 12.

Technological screws 16 are screwed into the through threaded holes of the squeeze ring 6 until they stop in the flange 2, while the squeeze ring 6 moves away from the flange 2, acts on the material frame and tends to separate it from the forming part 1 of the mandrel, which greatly simplifies and simplifies the removal of the workpiece, strength the adhesion of which to the mandrel after curing can be significant.

The practical application of the invention has confirmed the high reliability of the mandrel for the manufacture of products from composite materials.

Claims (4)

1. A mandrel for the manufacture of articles of composite materials containing a forming part made in the form of a hollow truncated cone, a cover and a flange connected respectively to the small and large ends of the forming part, characterized in that the flange is fastened with removable squeezing and clamping rings covering an annular gap forming part, while the cavity formed between the inner surface of the squeezing ring and the outer surface of the forming part is communicated through openings made in its wall, with fittings placed inside the mandrel equipped with a shut-off valve, the lid being fastened to a ring covering its peripheral surface, the outer surface of which extends beyond the contour of the forming part, forming a ledge in the joint zone with it. 2. The mandrel for manufacturing products from composite materials according to claim 1, characterized in that a series of through threaded holes are made in the squeeze ring for screwing the screws all the way into the flange when removing the workpiece from the mandrel. 3. The mandrel for the manufacture of products from composite materials according to claim 1 or 2, characterized in that the squeeze ring is fastened to the flange by bolts, the heads of which are covered by a clamping ring, fastened to the squeeze ring by bolts, the heads of which, in turn, are covered by an additional ring, countersunk screws secured to the squeeze ring. 4. The mandrel for the manufacture of products from composite materials according to claim 1, characterized in that the lid is fastened with a ring covering its peripheral surface with bolts, the heads of which are covered by a second ring, mounted to the first ring with countersunk screws.

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