Crankshaft bearings

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Plain bearing shell for a marine diesel crankshaft

A crankshaft bearing is a highly specialized bearing for mounting the crankshaft in the engine block of internal combustion engines and in reciprocating compressors .

Modern bearing designs are designed as plain bearings as well as ball bearings or roller bearings . The slide bearings, see the illustration of a bearing half-shell, work hydrodynamically - they are supplied with an oil flow from the oil pump . Inside the plain bearing, the frictional entrainment of the oil at the crankshaft bearing causes a wedge-shaped pressure film to build up, which is always designed so that there is as little metallic contact between the crankshaft as possible and the plain bearing. In the case of vehicle engines whose oil pump depends on the engine speed , mixed friction that causes wear cannot be completely avoided when starting . In marine engines, however, decoupled oil pumps are used, which are started with advance regardless of the engine speed, whereby a hydrostatic lifting of the crankshaft from the bearings and mixed friction-free start-up of the crankshaft is achieved before the engine is started.

Nowadays (2018) there are crankshafts with ball bearings or roller bearings in simple model construction internal combustion engines , in two-stroke engines for mopeds, in four-stroke engines for scooters and motorcycles through to automobile engines .


  • Wilfried Staudt: Handbook Vehicle Technology Volume 2. 1st edition, Bildungsverlag EINS, Troisdorf, 2005, ISBN 3-427-04522-6
  • Peter Gerigk, Detlev Bruhn, Dietmar Danner: Automotive engineering. 3rd edition, Westermann Schulbuchverlag GmbH, Braunschweig, 2000, ISBN 3-14-221500-X