DE823790C - Process for the manufacture of bodies containing cavities - Google Patents

Description

Those made from powders, e.g. B. from: metal or carbon powders to be produced So far, bodies have been pressed into molds in which to form the desired cavities either projections or depressions are provided or appropriately designed Cores are inserted, followed by sintering. When the cavities of the If the finished body is to be completely or approximately completely enclosed, the cores must or molds formed in several parts or the bodies themselves are pressed in parts, which are subsequently put together. All of these procedures are cumbersome and result in subsequent processing difficulties, especially when subdivided into partial pressed bodies.

These deficiencies can be avoided according to the invention in that the cores are completely enclosed by the powder mass and as a material such substances are used for the cores that during the pressing process at least to persist temporarily in a solid state, from which they later especially in the Sintering go into a liquid or gaseous state, in which they optionally can escape or be withdrawn via the pores of the pressed body.

The method according to the invention is in the "drawing for a sintered Bearing bush explained with a completely enclosed cavity, namely Fig. i the pressing process and FIG. 2 the finished bearing bush.

In the compression mold 2 provided with an annular recess i, an annular core 3 is inserted, which is formed, for example, by a ring made of oil or water or a suitable gas, which is converted into a solid state by supercooling. The metal powder d is introduced into the mold in such a way that it completely surrounds the core ring 3. The mass is then pressed together with the aid of the punch 5. At the latest during the subsequent sintering of the pressed body, the solid state of the core material is canceled, which evaporates and escapes through the pores of the pressed body or is optionally removed from the interior of the pressed body by blowing or suction. The result is an already dimensionally stable pressed body 6, which is particularly suitable for use as a bearing bushing without further processing, because it has a cavity 7 completely enclosed by the porous material, which can be filled with lubricating oil and releases it to the running surface during operation according to the invention does not require any special external lubrication during operation and has the further advantage that the permissible speed can be increased and the bushing has a longer service life.

The cross section of the core 3 is expediently chosen so that it is at a deformation occurring during the pressing process is what is desired for the cavity 7 Profile results.

Claims (2)

PATEN TANSPRL, CHE: i. Process for the production of bodies containing cavities, in particular sintered bushings for bearings, by pressing and sintering powdered starting materials using cores, characterized in that the cores are completely enclosed by the powder mass and such substances are used as 1Verkstoff for the cores, which during remain in the solid state of the pressing process, at least temporarily, from which they later change into a liquid or gaseous state during the subsequent sintering, in (lein they can escape or be withdrawn through the pores of the pressed body. 2. After Sintered bearing bush produced by the method according to claim i, characterized in that that their hollow roughness serves as a lubricant chamber.