Crankshaft assembly for an engine of a portable tool

摘要

A portable tool such as a motor-driven chain saw is disclosed which includes a cylinder, a piston, a connecting rod and a crankshaft. The crankshaft is rotatably journalled in crankshaft bearings and a crankcase made of plastic is provided. The bearing shells of the crankshaft bearings are releasably connected only to the cylinder and independently of the plastic crankcase. The plastic crankcase is likewise attached to the cylinder in such a manner that a housing arrangement is provided which is free of transmitted forces and is fully independent of the crankshaft bearings.