SU220683A1 - Method of fastening metal parts - Google Patents

Description

A known method of bonding metal parts, such as steel, is that one part, such as a bearing sleeve, is cooled to a temperature of minus 100-140 ° C, and then combine it with a sleeve that has a normal temperature. When the temperature rises, the sleeve is cooled. The sleeve increases in diameter: and, as a result, it is pressed against the surrounding part, and this results in their bonding. The proposed stitch is different from the fact that by this method steel and bronze parts are fastened, for example, sleeves of a sliding bearing. For this purpose, the bronze bushing is cooled to a temperature of minus 30-60 ° C, and then it is combined with a steel bushing. At the same time, as the temperature of the bronze bushing increases, it is expanded with the help of a device that allows a certain contact pressure to be created between the surfaces of the bushing sleeves. The drawing shows in section this device. Its base 1 has a recess into which a steel bushing 2 is installed, enclosing a bronze bushing 3, mounted on a mandrel 4 with longitudinal cuts 5 and an inner conical surface 6. Moving by means of a press (not shown). A comparative calculation of the bonding strength of bronze and steel parts was carried out using the proposed and known methods. A steel sleeve with an outer diameter of d.QQ mm and an inner diameter of c / 83 mm was supposed to be pressed into a bronze bushing with an inner diameter (mm and a wall thickness of 1.5 mm with a maximum tension of a medium-press fit 6.085 mm. At that, the module elasticity and Punch coefficient, respectively: for bronze 1 11000 kg / cm2,, 35, and for steel 0 21000 kg / cm, 0.3. The strength of such a connection depends on the contact pressure, which according to the theory of elasticity (problem L me-Gadolin) according to the generally accepted formula P F + f). / 832 i 802 where Ci - 832 - 802 - (f 4 26.83, C,

then

0.085

 0.38 KZlmf.

R -26, 83, 5.73, g

11,000 21,000

So minor

contact pressure can not provide a nightly fastening of the sleeves.

According to the proposed method, co-tact pressure is obtained many times more, since the bronze bushing is applied to steel with help, and tools and presses. This contact pressure can be determined by the formula

,

where a is the coefficient of linear dissolution

for bronze, 0.000017 MMJMM. hail. The temperature difference is determined by the formula

Af 0.085 ad 0.000017.83

then P aMEi 0.000017-60-11000

 11.2 kg / ml12. Thus, the specific contact pressure between the sleeves according to the proposed 11, 2PA method increased by a factor of 30,

0.38

which ensures reliable connection performance.

Experienced checking of bonding of bopzovaya and steel bushings showed good results.

Subject invention

The method of bonding metal parts by cooling one of them and their subsequent combination, characterized in that, in order to increase the quality of bonding, the bronze part is cooled to minus 30-60 ° C, and then, simultaneously with its expansion from temperature increase, said part at the fixture is pressed against the steel part.