4.2.3 Crankshaft and main bearing
The crankshaft is made of forged carbon steel and axial diameter of the pin and journal is made larger to keep strength and rigidity that can bear high combustion pressure. The main bearing cap is fixed to the cylinder block with 2 pcs of bolt and side bolt and designed to increase combination rigidity and reduce vibration.
The tightening of the bolt of the main bearing cap is done by a hydraulic tightening tool to give sufficient and sure tightening force with a view to attempt better reliability and labor-saving to make exchange of the main bearing easier.
For the main bearing metal, aluminum metal which is rich in wear and abrasion resistance is introduced. By fixing 12 pcs of balance weight, sufficient oil film thickness is kept and makes it possible to run long time operation without overhauling.
Oil film analysis is made on the basis of finite journal bearing theory and calculation is made while considering oil groove of the metal, joining face of the upper and lower metal, lubrication pressure and heating value of the bearing operation.
