RU2455162C1 - Device for fabricating tubes from composite materials - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and may be used in production of reinforced tubes. Proposed device comprises outer case, inner core, thin shell arranged there between, and conical gates to seal cavity between thin-wall shell and inner core. Note here that said cavity serves to accommodate workpiece fitted in squeezer inserts. Note also that device is furnished with two lock rings with inner cylindrical bore changing into open taper press-fitted onto thin-wall shell tightly to tube billet ends so that inner bore taper is located on opposite side.

EFFECT: higher yield and quality.

2 dwg

Description

The invention relates to mechanical engineering and can be used in all sectors of the economy for the manufacture of reinforced pipes.

A device for the manufacture of pipes from fiber composite materials [A.S. No. 721306].

The device comprises a coaxially mounted external power clip, an inner rod made with a channel facing the outer surface, a thin-walled shell placed between them, and also conical gates that seal the cavity between the thin-walled shell and the inner rod. In the cavity between the thin-walled shell and the holder, a pipe blank is placed, enclosed in segments made in the form of a pair of half-cylinders and facilitating the assembly of the device.

The last operation of the assembly of the device is the preload of the conical valves axial force.

The assembled device is placed in a vacuum oven, heated to the desired temperature. In the cavity between the thin-walled shell and the inner rod, pressure is created using the working fluid (gas, water) supplied through the channel of the inner rod. Moreover, due to the pressure of the working fluid and high temperature, the pipe billet is compacted for a given exposure time.

This design has the following disadvantages:

At the final assembly of the device, uncontrolled gaps remain between the cone valves and the pipe blank, the value of which is affected by the mechanical wear of the cone valves, which displays their dimensions as the maximum deviations, and the degree of preload of the cone valves during assembly of the device. The remaining gaps can lead to the displacement of the parts of the pipe billet during tilting of the device, the violation of the design of the connection of the parts of the pipe billet, and a change in the linear dimensions of the resulting pipes due to the plastic flow of the pipe billet material into uncontrolled gaps.

The objective of the invention is to increase the stability of the linear dimensions and design of the resulting pipes.

The technical result is an increase in the yield of the product and the exclusion of the plastic flow of the material of the pipe billet.

This is achieved by the fact that the device for manufacturing pipes from composite materials containing an outer casing, an inner rod, a thin-walled shell and conical gates between them, sealing the cavity between the thin-walled shell and the inner core, and the cavity between the thin-walled shell and the holder serves to accommodate the workpiece, enclosed in crimp liners, while it is equipped with two tabs in the form of rings with an inner cylindrical hole, on the one hand turning into an open cone, Formation with interference on a thin-walled shell close to the ends of the blank tube so that the conical part of the internal opening positioned at the opposite side ..

Figure 1 shows the proposed device for the manufacture of tubular elements, General view; figure 2 is the same, in section, where

1 - inner core;

2 - thin-walled shell;

3 - pipe billet, including 3a - composite part, 3b - unreinforced ends;

4 - segment;

5 - a clamp;

6 - conical lock;

7 - external power clip;

8 - a cavity between the inner core and the thin-walled shell;

9 - sealing surface with conical valves;

10 - channel in the inner rod for supplying the working fluid.

The device in assembled form contains an inner rod 1, a thin-walled shell 2, a pipe billet 3 (consisting of a composite part 3a and end unarmoured ends 3b), segments 4, retainers 5, conical closures 6, made in the form of rings with a conical inner surface, an external power clip 7.

The device operates as follows.

A thin-walled shell 2 is put on the inner rod 1 with the pipe blank drawn on it. Then the composite part of the workpiece is enclosed in segments 4 and on both sides close to the ends of the workpiece, clamps 5 are installed so that the conical part of the inner hole is facing away from the pipe workpiece 3. The clamps are installed with an interference fit to prevent the workpiece from shifting during subsequent assembly and tilting of the device. Behind the clamps on a thin-walled shell, conical shutters 6 are installed with gaps that take into account the subsidence of the conical shutters during their subsequent preload. The resulting assembly is enclosed in an external power cage 7, after which the conical gates are pressed axially (tightening with nuts), thereby sealing the cavity 8 between the thin-walled shell and the inner shaft over surface 9.

The device is placed in a vacuum furnace, where it is heated, at the same time, the working fluid, which creates isostatic pressure in the cavity 8, is fed into the sealed cavity 8 through the channel 10 of the inner rod 1, through a thin-walled shell 2, through its plastic deformation, the pressure is transmitted to the pipe blank 3 and clips 5.

In this case, the thin-walled shell 2 enters the conical part of the clamps 5, preventing their shift and thereby the flow of the material of the pipe 3 during pressing.

At the end of the pressing, the heating and the vacuum pumping system are turned off, the pressure in the cavity is relieved 8. The device is cooled, the pipe is taken apart and the finished pipe is removed.

An example of the operation of the device is the manufacture of a pipe ⌀40 mm with a wall thickness of 1.5 mm, a length of 800 mm from a fibrous composite material of boralumin with aluminum end endings for connecting pipes in the structure.

The starting material for the assembly of the composite part of the pipe billet is a semi-finished aluminum-boron tape in the form of an ordered monolayer of boron fibers bonded with a 500 × 1000 mm aluminum layer (TU 92-04.06.010-90).

2 aluminum end caps made in the form of rings 50 mm high with an outer diameter of 60 mm. The inner diameter of the endings is 35 mm, on one side the hole is bored to a depth of 25 mm to a diameter of 41 mm for interfacing with the composite part of the pipe billet.

Prefabricated tape is cut into measuring segments 750 mm long so that their total width is 1256 mm.

On the middle part of a thin-walled shell in the form of a pipe segment of ⌀35 mm and a length of 1000 mm from stainless steel GOST 10498-82, measured sections of the semi-finished product tape (10 layers) are sequentially wound, thus obtaining a composite part of the pipe blank.

On both sides, aluminum ends are put on a thin-walled shell and thrust them onto the composite part of the pipe billet so that the composite part fits into the bored part of the inner end of the tip to the entire depth of 25 mm.

A thin-walled shell with the pipe blank on it is put on the inner core, after which the composite blank is enclosed in steel segments.

On both sides with an interference fit close to the ends of the pipe billet, clamps are installed in the form of steel rings, the inner hole of which is made with a cylindrical inlet part ⌀35Н7 / m6 and a conical outlet part. An open cone with an angle of 3 ° 30 'provides an increase in the output diameter by 2 mm (37 mm). The latches are set so that the conical part of the inner hole is facing away from the pipe blank.

Behind the clamps, conical valves are installed on both sides of the thin-walled shell with gaps of 2-3 mm. The resulting assembly is enclosed in a power cage, after which the cavity between the thin-walled shell and the inner shaft is sealed with axial force (tightening the nuts of the cone locks).

The device is placed in a shaft vacuum furnace, where argon is fed to the initial pressure P = 15-20 MPa and the device is heated to T = 550-600 ° C through the channel of the inner tube during continuous evacuation of the pipe billet, through the channel of the inner rod.

During heating, the pressure in the cavity between the inner core and the thin-walled shell increases to P = 30-40 MPa and is transmitted through the thin-walled shell through its plastic deformation to the pipe billet and clamps.

At the end of pressing, the heating and the vacuum pumping system are turned off, and the pressure is released. The device is removed from the furnace, cooled in air, disassembled, the pipe is removed along with the thin-walled shell and the thin-walled shell is removed mechanically.

The length of the ends is 50 mm, the length of the composite part between the ends is 700 mm, the overlap length of the composite part of the pipe and the end is 25 mm and the total length of the resulting pipe is 800 mm exactly correspond to the specified dimensions.

The proposed device for the manufacture of tubular elements in comparison with the known design has the advantages of:

1. Visually uncontrolled gaps between the pipe billet and the cone closures arising after the cone valves are pulled together when the device is fully assembled are replaced by visually controlled gaps between the pipe billet and the clamps.

This eliminates the displacement of the parts of the workpiece, the flow of pipe material into the gaps, violation of the design and dimensions of the obtained tubular elements, i.e. increase yield.

The resulting device is used in the manufacture of cylindrical tubular elements from composite materials.

Claims (1)

A device for manufacturing pipes from composite materials containing an outer cage, an inner rod, a thin-walled shell and conical valves placed between them, sealing the cavity between the thin-walled shell and the inner rod, and the cavity between the thin-walled shell and the cage serves to accommodate a workpiece enclosed in crimp liners, characterized in that it is provided with two clamps in the form of rings with an inner cylindrical hole, on the one hand turning into an open cone, installed tightened on a thin-walled shell close to the ends of the pipe billet so that the conical part of the inner hole is located on the opposite side.

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