SU1751471A1 - Lap joint of sheet parts - Google Patents

Abstract

The use of riveting and assembly production, aircraft manufacturing, the manufacture of multi-shear rivet joints of increased resource The essence of the invention lap joint contains several sets of rivets the gap between the core of the rivet and the part is installed bushings of sealing material with a low modulus of elasticity 5 silt

Description

The invention relates to mechanical engineering, in particular to aircraft construction, and can be used in the manufacture of multi-shear rivet joints of sheet parts of increased resource.

Cut-off rivet joints are known, consisting of joined sheets and several rows of rivets. The fatigue failure of known compounds occurs along the extreme rows of rivet holes and is largely determined by the level of stresses seen along the walls of the holes. To reduce the force loading of the extreme rows of rivets, a reduction in their diameter is used as compared to the internal rows.

However, the effectiveness of the known solution is low, as this reduces the area of the cm.

Reduced force loading is also achieved when using stepwise or short connectors.

However, this greatly complicates the manufacturing technology of the joint and is applicable for relatively thick bags, for which the bolts are used.

The closest in technical solution and attainable distance is the connection of sheet metal parts, which implies the installation of extreme bolt rows in a welded joint with a tension in one connecting sheet and with a gap in the other. This design solution allows reducing the amount of bending stresses across the section extreme rows of joints. In addition, it allows the extreme rows of fasteners to be unloaded by stress, which increases the fatigue life of the joined sheets

However, the application of the known compound for riveted joints is very difficult, since the rivets of the extreme rows collapse when riveting without a backlash from the sheet. In addition, the tightness of any joint is impossible.

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This is done by eliminating the slotted channels between the fastener rod and the hole wall, as well as between the sheets to be joined. The known solution reduces the length of the slotted channel between the rod and the wall of the hole and almost completely opens the channel between the connecting sheets. This significantly reduces the tightness of the joints, which significantly reduces its scope. In addition, the installation of the extreme rows of fasteners (bolts, rivets) with a tension in one of the joined parts leads to the tightening of one joined sheet to another, inside the gap. This impairs the quality of the joint, disrupts its contour, which is unpleasant, especially for aerodynamic surfaces.

The purpose of the invention is to improve the quality of a predominantly riveted joint.

In order to achieve this goal, the connection of parts consists of overlapping sheets by means of several rows of fasteners, for example, rivets. Extreme rows of fasteners are installed with a gap in the part forming the edge of the overlap and with tension in the second part. A sleeve of low-modulus sealing material is installed in the gap between the core of the fastener and the wall of the hole.

FIG. Figure 1 shows the p-tyre single-rivet riveted joint of sheet metal parts, side view; in fig. 2 - a fragment of the joint structure in the region of the installation of the extreme rows of rivets; in fig. 3 - 5 - the technological process of assembling riveted joints of sheet metal parts.

The riveted joint of parts consists of overlapping sheets 1 and 2 by means of several rows of rivets 3. Fatigue failure of the joined sheets occurs along sections of the parts under the extreme rows of rivets, which are first with respect to the load on the joined sheet. For example, sheet 1 is destroyed by section A-A, and sheet 2 by section B-B (Fig. 1). It is advisable to increase the fatigue life of the joined sheets to reduce or even eliminate stresses on the extreme number of rivet holes. To achieve the desired effect, the rivets are installed with a gap in the part forming the overlap edge (part 2, fig. 2) and nat. in the reciprocal attachment part — detail 1. To prevent the rivet from being closed when it is being riveted

A low-modulus sleeve 4 having sealing properties is installed in the opening of a larger diameter.

Technological process of education

the rivet joint consists of the following operations: assembling the parts to be joined into a package, joint drilling of the joined sheets, disassembling the package, making the last holes in the joined sheet of a larger diameter, for example, reaming, deburring; assembling into a package of joined sheets, installing internal rows of rivets into the holes and riveting them, installing rivets in the extreme rows of holes (Fig. 3): installing a low-modular sealing sleeve 4 on the rivet rod (Fig. 4); Riveting of the extreme rows of rivets by the selected type of riveting process (Fig. 5).

Under the improvement of the quality of the rivet joint, the improvement of the following joint parameters should be reduced: reduction or even elimination of possible rivet fill up when it is riveted, especially if the closing head is located on the side of the larger hole; increased tightness of the joint, since the presence of a sleeve reduces the possibility of a slit leakage along

rod rivet due to sealing of the sleeve from the side of the rod and with the wall of the hole, and due to its sealing properties (high adhesion of the surface of the sleeve to the rod and

hole wall); reduction of the possible retraction of one joined sheet to the inside of the response sheet, which improves the quality of the joint surface (especially important for aerodynamic bearing surfaces); radial distribution of the rod in the hole of a larger diameter is significantly reduced, which reduces the rivet tendency to completely fill the hole of a larger diameter and allows

the most, to receive the unloading of the extreme number of holes on the voltage of cm see.

In aircraft construction, the implementation of riveted joints of sheet parts made of material D16T, B95 with rivets from B65, D18 has found wide application. For the manufacture of sleeves, it is possible to recommend plastics (for example, fluoroplastic) with applying an adhesive layer on the side surfaces of the sleeve, or sealed materials such as VER-1, VITEF-1, which are used to make a harness seal on the butt surfaces of the aircraft. It should be noted that the modulus of elasticity of the material of the sleeve with these combinations of pairs of materials

3-4 times lower than the modulus of elasticity of the material of the joined sheets and rivet.

Thus, the use of riveted joints of parts allows improving its quality, which reduces the safety factors of the joint when calculating it, or increases the lifetime of the joint while maintaining the specified quality.

Claims (1)

The invention of the Compound sheet details overlap, containing located on the bottom Several rows of fasteners are installed, with the fasteners in rows along the edges of the overlap set with a gap in the part forming the edge of the overlap and with a tension in the second part, characterized in that. in order to improve quality. Preferably, the rivet joint, in the aforementioned gaps, are installed bushings of sealing material with a low modulus of elasticity. s FIG. 3 m 4ИГ.4 FIG.5