DD143563A1 - METHOD FOR THE PRODUCTION OF CAVITIES IN PISTONS - Google Patents

Abstract

Method for producing cavities in pistons for internal combustion engines and a cooling cavity arranged in the region of the piston head and for castings with cavities, characterized in that the molding material of solid mixture of the mixture under pressure and temperature is formed into a salt core.

Description

21 28 61 "* -

Title of the invention

Method for producing cavities in pistons

Field of application of the invention

The invention relates to the production of cavities in pistons for internal combustion engines with a arranged in the piston head part cooling cavity and castings with cavities, which is formed by a molten above the molten metal molding material mixture during casting «, Preferably this material should be easily triggered by water v / earth and therefore a variety of structural design possibilities of the cavities in the piston head part and other castings allows »

Characteristic of the known technical solutions

In general, voids are produced by casting on the sand used in the molding process. "For the present application of cooling channel pistons for diesel engines, a residue-free purging of the cavity from the Forrastoff is required for a reusable molding material having a melting point above the casting temperature and a Solubility, is therefore proposed in the patents - Swiss Patent No. Hr. 246046 »French Patent Specification No. 1,339 * 372 and the Federal Republic of Germany Patent Nos. 1302940, No. 968822 -

To use mold materials based on potash, sodium chloride and potassium chloride compounds and alkali compounds with synthetic molding materials. These mold materials are 'either not remove residue or too hygroscopic and thus not dimensionally stable for use in foundries, or in the complicated complicated and expensive to manufacture in the case of a core of alkali silicates and a synthetic binder »

The molding material must satisfy the increasingly complicated cavity shapes for modern diesel engine pistons in addition to the mentioned properties by a simple manufacturability, easy handling in the preparation for the casting process and sufficient design strength * The molding material used for the present invention includes besides a special function in engine operation From the knowledge of the stresses of the cores for foundry purposes are the disadvantages of the solutions, disclosed in BRD Patent ITr · 1238623 »apparent * Der aus Sodium and potassium chloride existing molding material is heated and produced by casting the contour of the core * This salt core shows sufficient shape strength for the foundry stresses and does not correspond to the mechanical and thermal Beanspr Castings * The process for producing salt cores described in BFRD Patent No. 1302940 is based on a printing and sintering process in a prescribed temperature and pressure range. * The Federal Republic of Germany Patent Nos. 310364 and No. * 2017925 modify the molding material with additional elements and the scope of an arranged in the piston head part annular salt core channel, which is attached by means of electron beam welding, much more »

Object of the invention

The invention makes it possible to produce cavities arranged in the piston head part and in castings in a technologically simpler way.

Essence of the invention

The invention has for its object to produce water-soluble cores, consisting of a solid mixture, under pressure and temperature for forced-cooled pistons and castings »

The demands on the resistance and the absorption of the stresses, which are transferred by the shrinkage on the molding material, have led to the inventive solution, a molding material mixture consisting of

"91-98 weight percent rock salt 1-2.5 weight percent talc

1 - 3 »5% by weight slate flour ~ 0-1,5% by weight porcelain feed,

to compact under high pressure «

The molding material used according to the invention by its specific composition in a process of shaping by a pressure application to 100 N / mm, preferably in the range of 15 to 65 N / mm with simultaneous sintering process at temperatures <c 500 ° Ö, preferably 350- 450 ⁰ C. manufactured"

The previously described disadvantages of the inventive solutions are eliminated and the possibilities of an economical production of salt cores and salt core cooling channel pistons are created.

Claims (3)

claims 1. Process for the production of cavities in pistons for internal combustion engine !! and a cooling cavity arranged in the region of the piston head and for castings with cavities, characterized in that the molding material used is formed from solid components of existing mixture under pressure and temperature to form a salt core. 2. The method according to item 1, characterized in that the molding material used preferably from 91 to 98 percent by weight of rock salt 1 -2.5% by weight of talcum · 1 - J, 5% by weight slate flour O - 1.5% by weight porcelain batch consists. j 3. Method according to item 1 and 2 characterized j that the molding off at a pressure <100 Ή / mr, preferably 15 to 65 N / mm and a temperature <. 5oo ° G, preferably 35o ⁰ G - 45o ⁰ C are formed.