Mahle International Gmbh

Jochen Kortas

Christof Geissler

Dieter Messmer

Joachim Schulz

Timo Estrum

A method for producing a piston may include producing a piston top part and a piston bottom part each including an inner support element having an inner joining surface and an outer support element having an outer joining surface. At least one of the joining surfaces may include a solder depository. The method may also include pre-machining at least one of the joining surfaces and introducing a high-temperature soldering material in at least one solder depository. The method may further include assembling the piston top part and the piston bottom part to form a piston body via creating at least one of circular contact and linear contact between the joining surfaces such that a gap width is 20 &#x3bc;m to 150 &#x3bc;m. The method may also include transferring the piston body into a soldering oven, melting the high-temperature soldering material via heating the piston body, and cooling the piston body.

Method for producing a piston

The present invention relates to a method for producing a multi-part piston () for an internal combustion engine, comprising the following method steps: producing an upper piston part () and a lower piston part (), each having an inner support element () having joining surfaces () and an outer support element () having joining surfaces (), applying a high-temperature solder material in the area of at least one joining surface (oror), assembling the upper piston part () and the lower piston part () to form a piston body by establishing a contact between the joining surfaces (oror), placing the piston body in a vacuum furnace and evacuating the vacuum furnace; heating the piston body at a pressure of at most 10mbar to a soldering temperature of at most 1300&#xb0; C.; cooling the soldered piston () at a pressure of at most 10mbar until the high-temperature solder material is completely solidified. The present invention further relates to a piston () that can be produced by means of the method.

Multi-part piston for an internal combustion engine and method for the production thereof

The invention relates to a two-part piston () for an internal combustion engine, consisting of an upper part () and a lower part () which is screwed to the upper part. The upper part () and the lower part () are in contact with each other, partially by means of inner bearing surfaces () defining the lower side of an upper ring rib () and the upper side of a lower ring rib (), and partially by means of outer bearing surfaces () defining the lower side of the ring wall () and the upper side of a collar () applied to the lower part (). In order to avoid frictional rubbing, frictional heat sealing and pressure-related material heat sealing, at least one of the bearing surfaces () is easily and economically provided with a chrome layer () which has a structured surface comprising a plurality of raised parts and recesses.

Two-part piston for an internal combustion engine

The invention relates to a two-piece piston () for an internal combustion engine, comprising a piston base body () and a ring element (), which is soldered to the piston base body () by an upper solder connection () having the length b, which is disposed on the radial inside of a piston crown () formed at least partially by the ring element (), and by a lower solder connection () having the length c, which is disposed radially outside on the top of a center part (). In order to improve the strength of the solder connections () and () due to pressure and temperature-related deformations of the upper piston part, the ring element () has a peripheral, upper, thinner wall region () in the region of the piston crown () radially outside the upper solder connection () and further a peripheral, lower, thinner wall region () between the ring section () and the lower solder connection (), wherein the thickness a and b of the thinner wall regions () and () has a lower value than the length b and c of the solder connections () and ().

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Murr, Germany

Jochen Kortas