SU1252045A1 - Apparatus for pressing articles from pulverulent materials - Google Patents

Description

The invention relates to powder metallurgy, in particular to press molds for pressing long thin-walled bushings.

The purpose of the invention is to improve the quality of products and the reliability of the device.

FIG. 1 shows the device, a general view in section; in fig. 2 is a section A-A in FIG. I.

The device consists of a detachable ferrule 1 of a collapsible matrix 2 in which lining 3 is placed, deforming elements D, made in the form of ring sectors, between which a wedge 5 is located, claws 6 of a loading element 7, in contact with deforming elements 4 and wedges 5 along conical surface m Oppositely located one to the other deforming elements 4 are interconnected by elastic elements 8 passing through grooves 9 made in loading element 7. The angle of inclination of the generatrix of the conical surface over which the loading element 7 contacts the bearing surface of the wedges 5 exceeds the angle of inclination of the conical surface loading element in contact with the supporting surface of the sector, by

arctgg-, - Htgf / 2

 SQ; 5rT til727rD d7

where H, D and d are the height, are the outer and inner diameters of the loading cavity, respectively; f- wedge angle.

The pressing device works as follows.

In the loading cavity of the device formed by the matrix 2 and the deforming elements 4, it is filled up

powder mixture. Thereafter, the molding cavity is closed by a cover 6 and the device is placed on the press table. Pressure is applied to load member 7. As a result of this, he, moving down, acts on the deforming elements 4 and the wedge 5 located between them. At the same time, the speed of movement of the wedges 5 is greater than the speed of movement of the deforming elements 4 due to the fact that the angle of inclination of the generatrix of the conical surface of the loading element,

in contact with the supporting surface of the wedges, exceeds the angle of inclination of the generatrix of the conical surface of the loading element in contact with the supporting surface of the deforming elements. In the process of moving the deforming elements 4 and the wedges 5, a radial molding of the powder mixture occurs. After that, the loading element 7 is retracted upwards, and the deforming elements 4 are returned to their original position by the action of the elastic elements 8. Due to the fact that the angle is chosen by a large self-locking angle (t arctan f, where f is the coefficient of friction of steel against steel), the return to the initial position of the deformed elements 4 entails a return to the same position and wedges 5. Further, the product is easy removed from collapsible die 2 when the clip 1 is removed.

The long-length, thin-sleeve bushings pressed by the proposed device have a uniform height tolerance; there are no digging and chipping on their inner surface. This makes it possible to reduce the gaps assigned to their further machining, in connection with which it becomes possible to save hard metal and reduce labor costs.

to

.

Compiled by G. Zagorsk Editor N, Bobkova Tehred L. Serdyukova Proofreader C, Shekmar

Order 4565/12 Circulation 757 Subscription

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 (2)

I. DEVICE FOR PRESSING PRODUCTS FROM POWDER MATERIALS, mainly thin-walled long bushings, containing a matrix, deforming elements made in the form of ring sectors and placed. in the matrix with the formation of a loading cavity and with the possibility of radial movement, and a loading element installed with the possibility of continuous contact with deforming elements on a conical surface, characterized in that, in order to improve product quality and reliability of the device, it is equipped with wedges placed between annular sectors with the possibility of continuous contact with them, contact with the loading element on a conical surface and radial movement, and of inclination of the generatrix of the conical surface of the charging member in contact with the wedges, the tilt angle exceeds the generatrix of the conical surface of the loading member contacting the annular sectors by an amount BTCigg- ^ g-g-y 'H -tg f / 2 - _a r _C tg_- _3n --_ 7-K ₅ - _H p where Η is the height of the loading cavity; D is the outer diameter of the boot cavity; <1 - inner diameter of the loading cavity; 8 - angle of the wedge. 2. The device pop. 1, characterized in that the loading element is made with grooves, and the oppositely located deforming elements are interconnected by elastic elements placed in the grooves. SU .... 1252045