SU1691589A1 - Method for making bolted joint of parts - Google Patents

Abstract

The invention relates to machine parts and can be used in the manufacture of multi-section bolted joints of aircraft structures. The purpose of the invention is to increase the fatigue life of the parts being joined. A method for obtaining part joining involves manufacturing parts with a series of holes, fasteners, and two gaskets. Each of the gaskets is made with a bending section and recesses at the ends. Connect the parts and gaskets in the package, and the gaskets are installed extreme in the package on one side. In addition, each of the gaskets is installed in the zone of the outermost and adjacent with it a number of holes of parts with a bend in the direction of the package. Install the fasteners into the holes of the package and tighten them. At the same time, the gaskets spread out and redistribute the load between the extreme and adjacent rows of fasteners. 5 il.

Description

The invention relates to machine parts and can be used in the manufacture of multi-section bolted joints of aircraft structures.

The purpose of the invention is to increase the fatigue life of the parts being joined.

FIG. Figure 1 shows the design of a single-bolt bottom bolt assembly before axial tightening of bolts; in fig. 2 - the same, the nature of the contact interaction of the extreme bolts with the joined sheets after axial tightening of the bolts; in fig. 3 - the same, after application of the operational load; in fig. 4, 5 - the construction of a high-strength gasket and its geometric characteristics in a plan view and a profile section.

According to the method, parts 1 and 2 are made with a series of holes, fastening elements 3, 4, 5 and a unloading element, which is made of two gaskets 6.

Each gasket is made with a curved section and recesses at the ends. Parts 1, 2 and gaskets 6 are connected to the bag, while gaskets 6 are installed on one side of the bag in the zone of the outermost and adjacent row of holes of the parts with a bend in the side of the bag. Bolts 3 are installed in the package holes and washers 4 are put on them, which are bolted 5.

Place of probable fatigue damage and. The connections are aaa alemeta section 1 and section bb for sheet 2. The bolts in the sections indicated are, relative to the operating load Pz applied to the sheet, first: the bolts in section aa are the first for sheet 1, and in section bb - for sheet 2. In the areas between the extreme rows of bolts (between the first and second rows of bolts) there is a gasket 6 made of a more durable material than the joined sheets (Fig. 1). After osEO 00

SP 00)

the first bolts of the extreme rows in the joined sheets create preliminary contact stresses: over the first row

bolts, and on the second row (Fig. 2). In this case, the magnitude and direction of action

oji stresses are opposite to the actions of future operating stresses, see wsm. After the application of the operational load on the connection Re, a redistribution of the stress of smi occurs. But for a destructible sheet in a dangerous section, there is a decrease in the level of operating stresses by the amount previously created. So, for example, for sheet 1 in section aa:

SGSme1 SG / m1, (1)

where Osm.1 is the magnitude of the operating voltage of the smith without the use of high-strength gasket.

In the construction of the joint of parts, the second row of bolt holes are reloaded. For example, for sheet 1 through the second row of holes Ј

Osm.e2 - Omm.2

Ok2

(2)

However, this loading in fatigue is not dangerous, since the second row of holes reduces the level of tensile stresses in the sheet and the joined sheet in this section is not destroyed. This is also true for the case of sheet 2 being reloaded in section aaa, since the sheet along the last row of bolts is not destroyed, the gasket b must be bent so that the direction of the deflection is in the direction of the sheet in contact with it, otherwise is implemented. The execution of the thrust requires that the pitch of the holes in the flat gasket (before its bending) tpf be greater than the pitch of the corresponding holes in the joined sheets ti1. The difference in these steps will determine the necessary thrust force.

This method of obtaining a bolt joint is characterized by a greater magnitude of bolt thrust, since the clamping force does not overcome the contact-resistance of the gasket-sheet; less weight of the joint; for single-joint joints, the magnitude of the bending stresses in the joining sheets is reduced due to

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outside the eccentricity of the transfer of the run-off, as the gasket being placed on top bends the sheet in the opposite direction to the operational bending (when loading the operational load, the sheet is stretched on the contact surface with the response sheet).

For aircraft construction, the use of duralumin alloys of the type D16T, B95 for joined sheets and steel fasteners of ZOHGSA, ZOHGSNA, 16ХСН or titanium BT-16 is typical. For the manufacture of gaskets, it is advisable to use the same materials as for the manufacture of bolts. The size of the thrust (the difference in the pitch of the holes in the gasket and sheets) of the bolts must be chosen so that the condition

oЈi about | m 1,

In this case, the technical efficiency of the developed joint of parts will be greatest. The developed connection of parts is advisable to use for connecting packages of medium and large thickness of multibore (4-8 rows) bolted joints. It is advisable to increase the magnitude of the axial tightening of the extreme bolt ranges by 15–20% compared to the average bolts. The manufacturing technology of the joint does not differ from the serial one: the drilling of a package of connected parts, the installation of internal rows of bolts and their tightening, the installation of gaskets, the installation of extreme rows of bolts and their tightening.

Claims (1)

Claim Method A method for producing a bolted joint of parts, in which parts with rows of holes are made, fasteners, a relief element with four rows of grooves and two bending sections, connect the parts and the relief element into a package, combining the notches of the relief element with the ends and adjacent They have rows of holes in the parts, and between these rows of holes, the flexible sections of the unloading element, install the fastening elements in the holes and tighten them, which is different from the fact that increase service life by increasing the fatigue life of the joined parts, unload member is performed in two gaskets iegibnoy portion and two rows of recesses is performed on each of the gaskets which usta- nazlivayut extremes in the package with the bending direction towards the package, 6 SG fig 2 figl physical 6-6 FIG. five