A bearing device for internal combustion engines, comprising a crankshaft of
an
internal combustion engine and bearings supporting the crankshaft, and wherein
the crankshaft is made of steel having not been subjected to surface hardening
and having a structure, which is mainly composed of pearlite having the pro-eutectoid
ferrite fraction of at most 3%, and is processed to have the surface roughness
Rz of at most 0.8 m, and wherein the bearings have an aluminum bearing alloy
bonded to a back plate thereof and contain, as an alloy component thereof, at least
Si particles of less than 4 mass %, whereby early abrasion and scratches of the
crankshaft are suppressed to be equivalent to or less than abrasion loss and scratches
of conventional DCI shafts.
