| 摘要 |
To provide a power unit (20) in which the flow of cooling air being taken in can be made smooth and the quantity of cooling air introduced into a transmission chamber (50C) can be enlarged. A power unit (20) wherein a fixed pulley half (51s) disposed on the transmission case cover (24) side of a drive pulley (51) provided on a crankshaft (40) of a belt type non-stage transmission (50) is equipped with a cooling fan (51F), a transmission case cover (24) is provided with an annular bearing part (24Fa) for rotatably supporting an end part of the crankshaft (40) through a bearing (43), an outer periphery side wall in the outer periphery of the annular bearing part (24Fa) is provided with cooling airflow inlet ports (24Fe) for introducing a cooling airflow into the transmission chamber (50C), and an inner-side side wall on the inner side of the annular bearing part (24Fa) bulges to the outside in the axial direction to form a bulging wall (24Fb) for covering the end of the crankshaft (40). |
