Schaeffler Technologies Ag & Co .kg

Stefan Dupke

Peter Sailer

Horst Gredy

Oliver Witter

Serge Kursawe

Holger Pätzold

Michael Schewe

Klaus Feldner

Jochen Blasch

Frank Schlerege

David Lang

Markus Wiedmann

A method for producing a reduced friction sliding surface on a machine element includes applying a coating comprising amorphous carbon to a surface of the machine element and locally heating the coating with a laser. The coating is heated to a temperature below an evaporation temperature of the coating to achieve a local volumetric increase in the coating and a local increase in a layer thickness of the coating. A surface structure of the coating includes a multiplicity of elevations resulting from a local phase transformation of the coating from amorphous carbon into graphite due to the locally heating.

Method for producing a sliding surface

A cam follower for a valve train of an internal combustion engine, the cam follower being formed as a lever, which is U-shaped in cross-section, and produced from steel sheet without machining, and which has a floor wall () and lateral walls (and) extending therefrom, wherein a valve stem support () is disposed as a groove () at one end of the lever in a surface of the floor wall () facing away from the lateral walls (and). Lateral guide walls (and) of the valve stem support () are formed by chipless shaping so as to extend from and counter to the lateral walls (and) and are connected to a support wall () that forms a valve stem support surface (). The valve stem support surface () extends in a first plane (), which is spaced from a second plane (), which extends through an internal transition () between the lateral walls (and) and the adjacent guide walls (and), in the direction of ends () of the lateral walls (and). In order to reduce stress and resulting cracks, an inner radius R is provided at the transition (and), by which radius a free space () is created between the lateral wall () and the guide wall (), which free space narrows towards the end () of the respective lateral wall ().

Cam follower for a valve train of an internal combustion engine

A support element for the valve train of an internal combustion engine, having a hollow cylindrical housing that holds a displaceable piston. The piston has a hollow cylindrical pressure part and a pot-shaped work part axially adjacent thereto. An inner space of these parts forms a storage space for hydraulic medium. A high pressure space is defined by a base of the work part and the housing. The storage space and the high pressure space are connected hydraulically by a non-return valve with a ball for automatic lash compensation of the valve train. The piston is supported by a compression spring on the housing base, and a retaining ring is arranged radially between the pressure part and the housing, which limits axial travel of the piston. The ball is movably held in the base of the work part in an axial ball guide having first and second integrally formed ball seats.

Support element for a valve train of an internal combustion engine, and method for production of support element

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Kodnitz, Germany

Stefan Dupke