DE1138301B - Inlay ring for a light metal piston for internal combustion engines to be produced by die pressing - Google Patents

Description

LIBRARY
f OF THE GERMAN VpATEJJTAMTES J

NOTICE THE REGISTRATION ANDOUTPUTE

Publication: OCTOBER 18, 1962

The invention relates to an insert ring in a light metal piston for internal combustion engines is poured. The ring is located in the piston head behind the piston ring grooves or else still above the same and serves to create a cavity for the coolant. The light alloy piston is produced from a cast blank by forming by means of die presses.

In the case of die-pressed pistons, it is known to work out the cavity from the outside by cutting and subsequently welding or shrinking on a cover piece. Deliver these measures however, no secure seal, because the cover piece under the influence of thermal Alternating stress can either tear or become loose.

A not previously known proposal is to pour a massive ring body where the Cavity should arise. This insert ring has the height of the cavity, but only a small wall thickness and consists of a material that does not weld to that of the casting. The cast blank is then die-pressed. Then the insert ring is drilled from the outside and the compact is heated. The cavity is thereupon by widening the gap between the insert ring and the material of the Generated compacts by means of a pressurized liquid or a gas. The insert ring needs not to be removed. However, the implementation of such an expansion process requires connection special supply and discharge means together with devices such as pump units and measuring instruments. This results in high manufacturing costs for the piston.

Furthermore, it is z. B. for the manufacture of gas turbine blades known to pour a massive insert into a blank, which is followed by a Takes part in hot forming. The filler is then removed by etching. Etching out a massive insert in the form of a self-contained ring with the cross section of a coolant cavity would, however, involve an unsustainable expenditure of time and resources.

Therefore, it is proposed according to the invention to choose a hollow ring as the insert ring, which with regard to its cross section is adapted to the ring cavity to be produced. The required surface of the annular coolant space is easy by etching out the metallic Material of the hollow ring, for. B. by nitric acid to achieve. The etchant is the option given to flow through the annulus and insert ring for one by die pressing light metal pistons to be produced

for internal combustion engines

Applicant:
Karl Schmidt GmbH,

Neckarsulm (Württ.),
Christian-Schmidt-Str. 10

Dipl.-Ing. Friedrich Wilhelm Rabenau,

Neckarsulm (Württ.),
has been named as the inventor

to run around there so that the material of the hollow ring can be removed on all sides.

So that when the insert ring is poured in, its position in the axial direction is precisely maintained to choose the dimensions of the ring so that the cross-sectional area of its wall becomes his total area cross-section such as the specific weight of the piston material to the specific weight of the ring behaves. In other words, the weight of the insert ring should be equal to the weight of a full ring of the same overall cross-section made of the piston material. For example, if the Inlay ring made of iron, the aforementioned aspect ratio must be 2.7 to 7.9 behavior. The hollow ring can also, for. B. made of copper.

About the atmospheric equilibrium of the hermetically sealed hollow ring at the melting temperature of the piston material, the enclosed air content should only produce the room pressure at this point result. The creation of atmospheric equilibrium should create an overpressure in the cavity of the ring and tearing of the latter when pouring can be prevented.

The air in the ring body can be removed by making a small hole and heating the Remove the ring to above the melting point of the piston material.

The heating temperature can be 700 ° C., for example. To check the atmospheric Equilibrium becomes an evaporating substance,

209 677/118

such as paraffin, introduced into the ring. When heated, the steam and its Whistling sound perceptible, which lasts until equilibrium is reached. Then the Opening of the hollow ring closed.

There is also the possibility of avoiding deformation of the insert ring during During the swaging process, fill the cavity with rosin or zinc or some other easily fusible To fill in material with a melting point below that of aluminum. After the pressing process has been completed, the cavity of the ring is drilled from the outside and the piston is brought to the melting temperature of the substance introduced into the cavity is heated so that it can flow out.

Claims (4)

PATENT CLAIMS: 1. Inlay ring, which is cast into a cast blank to be formed into a light metal piston for internal combustion engines to create an annular cavity for the coolant in the piston head part at the desired location behind the later grooves for the sealing rings, characterized in that it has a cross-section of the ring cavity is adapted hollow ring made of fabric that can be etched away. 2. insert ring according to claim 1, characterized in that its weight is a massive Ring of the same overall cross-section from the piston material corresponds. 3. insert ring according to claim 1 and 2, characterized in that its enclosed air content the room pressure only results at the melting temperature of the piston material. 4. insert ring according to claim 1 to 3, characterized in that it with a substance whose Melting point is below 500 ° C, is filled in. Considered publications:
German patent specification No. 1 056 908. Legacy Patents Considered:
German Patent No. 1127181. © 209 677/118 10.62