SU1337193A1 - Apparatus for compacting elongated thin-walled bushes from powder - Google Patents

Abstract

The invention relates to the field of powder metallurgy, in particular, to devices for the pressing of long thin-walled bushings from powder. The aim of the invention is to improve the quality of the extruded products. Pre-cast paraffin forming element 5. The latter together with the centering element 3 is installed inside the matrix 2 on the lining 1. In the cavity formed by the matrix 2, the lining 1 and element 5, cover the mixture, and then install the cover 8 so that the holes 9 coincided with the corresponding holes 10. The lid is attached to the die with the help of pins 11. Heater 4 heats element 5 to a temperature of 35-40 ° C. Thereafter, an axial force is applied through the punch 6 to the molding element 5. Thus there is a uniform radial pressing of the charge to the specified dimensions of the sleeve. The bushing is pressed out together with the forming element. The device makes it possible to obtain sleeves with a uniform density of height with no surface waviness. 2 ill., 1 tab. tpuP.i

Description

113

The invention relates to powder metallurgy, in particular, to devices for the pressing of long thin-walled bushings from powder.

The aim of the invention is to improve the quality of the extruded products.

FIG. 1 shows schematically the device, the initial position; in fig. 2 - the same at the time of pressing the sleeve.

The device consists of a matrix 2 placed on a lining 1, inside of which there is a centering element 3 with a heater 4, covered by a forming element 5 made of paraffin. The mold also contains a punch 6, a stopper 7 and a cover 8 mating on the outer cylindrical surface with the die 2, and on the inner cylindrical surface - with a forming element 5. On the outer cylindrical surface of the knurl 8 and the lateral surface of the die 2 are made coaxial radial holes 9 and 10 in which P.'s pins are placed

The device works as follows.

A conventional mold in the mold is pre-molded or molded paraffin molding elements (100% density), the dimensions d and h of which correspond to the condition:

d V 3 d - 2 D

(one)

H (d - d..) 3 d 2,

D - d.

(2)

where d.

1 - respectively, the outer diameter and height of the paraffin element; d, O, H, respectively, the inner and outer diameters and the height of the long thin-walled sleeve in compressed form; dp is the outer diameter of the centering element. The obtained paraffin forming element 5 together with the centering element 3 is installed inside the matrix 2 on the lining 1. In the cavity formed by the matrix 2, the lining 1 and the forming element 5, cover the mixture, and then install the roof 10

371

932

8 so that the holes 9 on its outer cylindrical surface coincide with the corresponding holes 10 in the matrix 2. The cover 8 is attached to the matrix 2 by placing in the coaxial holes 9 and 10 of the pins 11. Next to the cover 8 set the limiter 7, whose height is equal to:

X

2H (P - d)

3 di - 2 D2 - d

(3)

five

0

five

0

45 50 55

a Forming element 5, made of paraffin, is a punch 6.

A heater 4 is connected to the mains, which heats the molding element 5 to 35-40 0. After that, an axial force is applied through the die 6 to the molding element 5.

In this case, the forming element 5, decreasing in height to a predetermined value H (height of the compressed sleeve), increases in diameter to the value d (internal diameter of the pressed sleeve). This increase in diameter due to the high ductility and fluidity of the paraffin heated by heater 4 to 35-40 ° C is uniform over the entire height of the compression sleeve. Thus, uniform radial pressing of the bristles to a given size of the compression sleeve takes place.

After pressing, the sleeve is extruded from the mold together with the forming element, after which it is heated to 90-100 seconds. In this case, the paraffin, melted, impregnates the pressed billet.

Example. In the proposed device, a batch of long thin-walled bushings of hard alloy VN20G2 was pressed. The outer diameter of the bushings is 50 mm, the internal diameter is 46 mm, and the height is 50 mm. The diameter of the centering element dj-T is 16 mm.

The molding element, molded from paraffin, had the dimensions determined from the expressions (O and (2): d 36.7 mm, h 81.9 mm. The heating temperature of the paraffin was 40 C. The pressed blanks had a uniform density distribution in height, and after sintering the correct geometrifig .2

Compiled by L, Gamayunova Editor K. Krupnin Tehred L. Oliynyk Proofreader I. Muska

4079/12

Circulation 740 Letter

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

Claim A device for pressing from powder of long thin-walled bushings containing a matrix placed on a lining, a punch, a paraffin forming element and a stopper, characterized in that, 35 in order to improve the quality of the molded products, it is equipped with a centering element with a heater and a cover placed in it, mating along the outer ₄ θ cylindrical surface with the matrix, and along the inner, mating with the forming element and fixed on the matrix. Compiled by L. Gamayunova Editor K. Krupnina Tehred L. Oliinyk Corrector I. Muska Order 4079/12 Circulation 740 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and printing company, Uzhhorod, st. Project, 4