Crankshaft support structure in internal combustion engine

摘要

In a crankshaft support structure of an internal combustion engine, an oil pump can be miniaturized with miniaturizing the internal combustion engine by using a slide bearing. In the support structure for the crankshaft supported by right-left split crankcases 25 which are joined from both the sides in the axial direction of the crankshaft 41 so as to sandwich the crankshaft 41 therebetween, slide bearings 111 are applied to both crank bearings for supporting both the ends of the crankshaft 41, and a roller bearing 112 is applied to a bearing for a big end portion 42.

主权项

1. A support structure for a crankshaft of an internal combustion engine supported by right-left split crankcases that are joined from both sides in an axial direction of a crankshaft so as to sandwich the crankshaft therebetween, characterized in that both crank bearings for supporting both ends of the crankshaft comprise slide bearings, and a bearing for a con-rod big end comprises a roller bearing the slide bearings are bisectionally constructed, split faces passing through a crank axis line and both side surfaces in an axial direction of the slide bearing are configured to be flat, a bush having a higher rigidity than material of the crankcase is disposed in a bearing press-fit hole of the crankcase wherein an oil pump is disposed to be shifted to one side in the axial direction of the crankshaft, oil is introduced from the oil pump through a crankshaft end to the con-rod big end by a first oil path penetrating through the shaft, and oil is introduced from support member sides of the crankcases to the slide bearings by a second oil path.