RU2418999C1 - Procedure for connection of parts - Google Patents

Abstract

FIELD: machine building. ^ SUBSTANCE: procedure for connection of parts consists in alignment of parts so, that one parts envelopes another and in their fixation. Also, an element conjugated with a cavity in the enveloping part is made on the end of the enveloped part; this element increases in cross section in the direction to the end of the part. The distinguished feature of the claimed procedure is fabrication of the enveloped part out of composite material, while the enveloping part is made out of metal. The latter is compound and consists of straps with external thread and of a sleeve with internal thread. Parts are connected successively. First, straps are aligned with internal thread, further, the sleeve is aligned with the straps. ^ EFFECT: increased strength and reliability of connection of metal parts with parts out of composite materials; repair ability of connection. ^ 3 dwg

Description

The invention relates to methods for connecting metal parts with parts made of composite materials spanning one another (for example, a metal tip and a carbon fiber rod), used mainly in spacecraft in open space under the influence of tensile loads.

A known method of connecting parts covering one another and working in conditions of alternating temperatures, using the adhesive according to patent No. 2179268, in which glued parts covering one another are prepared and a heat-conducting mesh base is placed between them, on top of which an adhesive layer is applied, they are combined and fixed details, in this case, as a heat-conducting mesh base, a knitted cord-stocking of metal threads is used, the thickness of which in the stretched state is close, but not more than the thickness of the adhesive layer between the joined details that put on the male part to fit and fix the details before combining the edge from slipping.

The disadvantages of this connection are:

- if the dimensions of the female part are limited, due to structural considerations, the cross section of the male part and significant axial loads (for example, the length of the female part is 20 mm, the diameter of the female part is 9 mm, the diameter of the rod is 3 mm, the tensile load is 200 kg), this type of connection does not provide the required strength and reliability of the connection due to the small area of glue, especially at extreme positive temperatures;

- the quality of the adhesive joint depends on the uniformity of the mesh structure of the installed stocking cord, which may be impaired when installing the female part;

- if the female part or male part is damaged, the connection is not repairable.

A knot for connecting a tubular part to a flat one is described in SU 378667 A, F16B 17/00, 07/13/1973, in which, in order to enable the tubular part to have a collar at its ends, a sleeve installed in a flat part is made of elastic material with divided into sectors by an external protrusion, having an ovoid shape in cross section and clamping the tube collar (prototype).

The disadvantage of the prototype is that its use in limited small dimensions of the nodes operating in alternating temperatures when exposed to high tensile loads will lead to an increase in the dimensions of the connection at least in cross section due to the need to strengthen the elastic sleeve (with a diameter of 9 mm the elastic element will bear extremely small load, in addition, each sector of the sleeve works as a lever, and at the point of transition of the sector to the main solid part of the sleeve, the load increases, striving from tear sector. This phenomenon requires additional amplification elastic sleeve). In addition, when the nut is tightened, the elastic sleeve preloads the tubular element (in our case, the carbon fiber rod) in the direction of its axis, trying to crush it, which significantly reduces the bearing capacity of the joint when it has to withstand the working load. The presence of a large number of sectors in the sleeve does not guarantee equality of the pressure value of each sector of the sleeve on the tubular element (rod), which will lead to uneven loading over the cross section at the junction of the sleeve and the tubular element, and this will also affect the bearing capacity of the joint, since the parts are made of composite materials are sensitive to uneven loading. Also, uneven loading will result in the fact that when tightening the nuts of the sector, turning around their base, they will put more pressure on that part of the shoulder that is closer to the cylindrical part of the tubular element (rod) than its edge, thus the joint bearing capacity will decrease .

Finally, the elastic sleeve under the influence of space factors (radiation, extreme temperatures, vacuum) will quickly collapse.

The objectives of the proposed method for connecting metal parts with parts made of composite materials are:

- increasing the strength and reliability of the connection of metal parts with parts made of composite materials;

- ensuring maintainability of the connection.

The tasks are solved due to the fact that the parts are combined in such a way that one part covers another, at the end of which an element is made, increasing in cross section towards the end, mating with a cavity made in the covering part, after which they are fixed. The covered part is made of composite material, and the female part is made of metal, while it is made of a team consisting of overlays with an external thread and sleeves with an internal thread, and assembled sequentially, combining the overlays with the covered part first, and then the sleeve with overlays.

The invention is illustrated by drawings, where in Fig.1 shows a General view of the connection, Fig.2 is a covered part (rod) of composite material, Fig.3 is a covering part (metal tip).

The rod 1 is made in the form of a cylinder of unidirectional carbon fiber, interconnected by a binder. At the end of the rod during its manufacture, a reverse cone is formed in such a way that the fibers in the conical part of the rod are directed along the generatrix of the cone and are evenly distributed. The void in the conical part of the rod is filled with a binder with the chopped carbon fiber added to it, after which the rod is polymerized. The tip 2 consists of three parts - two inner linings 3 and 4 and an outer connecting lining, sleeve 5. Lining 3 and 4 are obtained from one body of revolution having an external thread, inside which is made a cone, repeating in shape a cone at the end of the rod, and cut along the plane of symmetry. The sleeve 5 is a body of revolution having an internal thread for interaction when assembling the connection with the plates.

The method is implemented as follows.

On the conical part of the covered part (rod), the plates are installed, after which the sleeve connecting the plates is installed.

The method of joining metal parts with parts made of composite materials implemented in this way allows us to solve the problems posed to increase the strength and reliability of the connection. Due to the fact that the connection is detachable, any failed part can be replaced.

This method is tested on a prototype at JSC ISS. The test results indicate the achievement of the objectives.

Claims (1)

The method of connecting parts, which consists in aligning the parts in such a way that one part covers the other and fixing them, while at the end of the male part an element increasing in cross section towards the end of the part mating with a cavity made in the female part is performed, characterized in that the male part is made of composite material, and the female part is made of metal, while it is performed by a team consisting of overlays with an external thread and sleeves with an internal thread, and assembled in sequence, first combining the plates with the male part, and then the sleeve with overlays.

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