摘要 |
When the rotational speed of an engine 11 is equal to or higher than 4000 rpm, the rotational fluctuation ratio of a crank shaft pulley 13 at an outer circumferential surface thereof is sometimes equal to or greater than 6%. Moreover, in the layout in which a V-ribbed belt 20 is wound on a plurality of pulleys 14, 15, at least one of span lengths is equal to or longer than 220 mm. The V-ribbed belt 20 includes a back reinforcement fabric. |