RU2368482C2 - Method of producing permanent joint - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: external part inner surface is furnished with 2 to 5 mm-pitch teeth. Assembly is carried out to make a clearance between external and internal parts. Internal part is subjected to upsetting.

EFFECT: higher quality and strength of joint, simplified assembly.

4 dwg, 1 ex

Description

The invention relates to the automotive industry and is used in the manufacture of blanks for the hubs of domestic cars or other parts that transmit torque.

A known method of assembly of parts, carried out by installing with a gap of one part in the hole of another with subsequent heating of the covered part to compensate for the gap between the parts. In the contact zone of the mating parts, cylindrical holes are made and elastic fixing elements are installed in them (SU 353808 A1, 10/09/1972).

The disadvantage of this method is the low build quality.

Also known is a method of fixedly connecting parts, which consists in placing rod elements on the mating surface of one of the parts to be joined, which are oriented along the axis of the parts to be joined and fixed in this position, then the parts are assembled by pressing, during which the rod elements are introduced into the body both parts to be joined. To increase the alignment accuracy of the shaft and the sleeve, an even number of rod elements is used, the elements of each pair being placed diametrically opposite to the axis of the parts to be joined. Orientation and fixation is carried out, for example, by fixing the rod elements in the holes or slots of the washer, which is installed on the end surface of one of the connected parts (RU 2093334 C1, 10.20.1997).

The disadvantages of this method are the high complexity of the method, and hence the high cost of the connection, and low build quality.

Closest to the proposed invention is a method of permanent connection of parts, which consists in the fact that one part is inserted into another and the female part is crimped by applying pressure to it from the working medium. At the same time, the pressure on the inner surface of the covered part is affected by the pressure of the working medium equal in magnitude and opposite to the pressure acting on the covering part (SU 389906 A1, 07/11/1993).

The disadvantage of this method is the low build quality, which does not allow the transmission of torque.

The objective of the proposed invention is the creation of such a method of permanent connection, which would eliminate the disadvantages listed above, and would allow to create a connection to transmit large torques.

The technical result achieved by the implementation of the invention is to provide a permanent connection made under conditions of stress (above the elastic limit) of all parts and capable of transmitting torque of more than 700 N / m (70 kgm), with high quality and durability of the assembly, as well as to simplify assembly technology and to improve the economic performance of the connection.

The specified technical result is achieved in that in the method of one-piece connection for transmitting torque, which includes assembly with a gap of the female and male parts and the subsequent settlement of the male parts, teeth with a 2-5 mm module are performed on the internal mating surface of the female component before assembly.

The invention is confirmed by drawings, where figure 1 shows a covered part; figure 2 - covering part; figure 3 - connection after precipitation; figure 4 is a photograph of the connection after precipitation.

The claimed method begins with the preparation of assembly parts: covered 2 and covered 1 parts. The male part 2 is made of a metal bar, which is cut into measured workpieces. The covering part 1 is cut out of the steel sheet in the form of a washer with a hole.

The size of the hole depends on the transmitted connection, torque.

On the inner surface of the mating enclosing part 1, teeth with a large module are cut. The size of the tooth depends on the torque and is determined by the empirical formula for calculating the collapse of the splined joint:

где

Where

σ _cm - stress on crushing, kg / mm ² ;

[σ _cm ] is the allowable stress on collapse, 8-12 kg / mm ² ;

M _cr.max - torque transmitted by the connection, kg · mm;

Ψ - coefficient taking into account the uneven distribution of efforts, (Ψ = 1);

F is the area of the lateral surface of one tooth on one side, mm ² ;

- количество зубьев в соединении, шт.;

- the number of teeth in the connection, pcs .;

r _cf. - average radius of application of force, mm.

The bar is installed in the washer 1 with a small certain clearance relative to each other. The prepared joint is installed under the press, for example, on the stamp of the hydraulic press, and the bar 2 is upset. The force developed by the press during the upsetting of the bar should be sufficient for filling the tooth cavities with metal by 90-100%. In this case, the height of the rod is determined from the condition of the coefficient of draft 50% and the deposited hub part of a particular product.

With a force greater than that required during two-sided compression, the joint is destroyed during upsetting. At lower pressures, tooth cavities do not completely fill, which subsequently, during further processing, will lead to destruction of the joint.

Draft is carried out under conditions of stress state of the parts, above the elastic limit. During deformation during the draft process, the average bar diameter increases and the bar takes a barrel-shaped form. The rod material is distributed in the radial direction on both sides of the washer along the cavities between the teeth until the entire inner mating surface of the washer comes into contact and the joint accepts the design dimensions of the final product.

The result is a compound 3, which by means of the teeth on the washer and the distributed material of the rod provides strength and the ability to transmit torque of more than 700 N / m (70 kgm).

If the tooth sizes of the female parts are incorrectly calculated, the hole diameter and the gap, the tooth cavities of the male part are not completely filled, which sharply reduces the strength of the connection or leads to the destruction of the connection.

Next, the resulting compound is sent for further machining.

Example. Assembly of an integral connection for the manufacture of the hub.

The measured workpiece of the covered part is cut from a steel bar - structural steel - a circle.

A covering blank in the form of a washer with a hole of 2-4 mm is cut from a sheet of structural steel. On the inner surface of the washer, large teeth are cut with a 2-4 mm module.

Parts are installed in each other with a certain gap between them and laid on the stamp of the hydraulic press.

With a force of 180.0 t.s. the rod is upset with a diameter of 36 mm in the radial direction from two sides of the washer, at which its average diameter increases to the design dimensions and fills the cavities between the teeth. Thus, a blank is formed for the manufacture of the hub.

Next, the resulting workpiece is sent to further machining, which results in the final product 4 (figure 4).

Correctly calculated values of the hole sizes of the covered part, the size of the teeth, as well as the size of the gap allow the permanent connection obtained by the claimed method to transmit large torques in excess of 700 N / m (70 kgm), and also to implement the claimed method without destroying the parts, i.e. without defective compounds, which affects the improvement of economic indicators.

This method simplifies the manufacturing technology of one-piece joints designed to transmit large torques, excluding pre-heating of parts or the use of additional parts, such as rod elements, which also affects the reduction in the cost of the finished product.

Simplicity and economic feasibility allows the claimed method to be widely used in industry, in particular in the automotive industry, in the production of clutch hubs for domestic cars.

Claims (1)

A method of integral joining of parts, including assembly with a gap of the female and male parts and subsequent settlement of the male part, with teeth with a 2-5 mm module being performed on the internal mating surface of the female component before assembly.

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