Patent ID: 7874949
Filing Date: 2011-01-25
Classification: F16H

Abstract:
1. A power unit comprising: an internal combustion engine including: an auxiliary machine located below the separating plane, and a transmission mechanism for driving an auxiliary machine with an endless transmission belt wound around a drive sprocket and a driven sprocket to drive the auxiliary machine; and a transmission including: an input shaft which receives power from the crank shaft; and an output shaft which lies below the input shaft and outputs power after gear shift, in which the input shaft and the output shaft are parallel to the crank shaft, wherein the drive sprocket is placed on the input shaft located above and away from the separating plane, the driven sprocket is placed on a drive shaft of the auxiliary machine located below and away from the separating plane, the transmission mechanism slidably touches the endless transmission belt and has a slender long first guide along a running direction of the endless transmission belt wound around the drive sprocket and the driven sprocket, an engaging part protrudes from the long slender first guide at a position centrally located between opposite ends of the long slender first guide, the engaging part for engaging with a pin which is provided on the upper crankcase in position between the drive sprocket and the separating plane, the first guide is fitted only to the upper crankcase by a fitting part formed on the first guide, and stretches across the separating plane between the upper crankcase and the lower crankcase.