Patent ID: 7273030

Claim:
A crankshaft support structure of an internal combustion engine, comprising: a cylinder block; a crankshaft having journal portions assembled to a lower portion of the cylinder block; wall-shaped journal support bases formed in the lower portion of the cylinder block and extending along a direction crossing with an axis of the crankshaft; semi-circular bearing portions respectively formed to undersurfaces of the journal support bases, the bearing portions accommodating half parts of each of the journal portions; and saddle-shaped bearing caps respectively mounted on the undersurfaces of the journal support bases in such a manner as to straddle the journal portions being accommodated in the bearing portions, whereby the journal portions are rotatably supported, wherein, each undersurface has a recessed portion that opposes a mount surface of the saddle-shaped bearing cap, and the undersurface, including the recessed portion, is provided with a thick portion thicker than other portion of the undersurface, the mount surface also has a thickness that corresponds to a thickness of the thick portion.