Patent ID: 7779727
Filing Date: 2010-08-24
Classification: F02N,F16H,Y10T

Abstract:
1. A power unit case for an internal combustion engine, said power unit case comprising: a crankcase for housing a crankshaft, and a transmission case for housing a transmission mechanism, said transmission mechanism comprising: wherein the main shaft is arranged above a space between the crankshaft and the counter shaft arranged at a position substantially horizontally behind the crankshaft; the gear-ratio selecting mechanism is arranged above the group of transmission gears on the counter shaft whose upper portion rotates toward a meshing portion of the group of transmission gears; and wherein the transmission case comprises a ceiling surface having a lubricating projection formed thereon and projecting downwardly above the transmission gears on the counter shaft, and at a location on a ceiling surface inside the transmission case where the gear-ratio selecting mechanism is supported, wherein the ceiling surface inside the transmission case where the gear-ratio selecting mechanism is supported is formed arcuate, and wherein the lubricating projection that projects downward is formed at a lowermost portion of the arcuate surface on a rear-half of the ceiling surface.