Patent ID: 7563187

Claim:
A belt drive system in which a drive belt is wrapped around a plurality of pulleys, wherein at least one of the plurality of pulleys is an auto belt alignment pulley comprising: a hollow cylindrical pulley body around which the drive belt is wrapped; and a support mechanism that supports the pulley body to allow the pulley body to rotate about its rotational axis and angularly move about a set pivot axis inclined at a predetermined angle forward in the direction of rotation of the pulley body with respect to the direction of a radial shaft load when viewed along the rotational axis, wherein the belt drive system is configured such that when the belt deviates to one side of the pulley body, the one side of the pulley body moves toward the direction of the radial shaft load and the pulley body moves angularly about the set pivot axis, and concurrently the one side of the pulley body moves forward in the travel direction of the drive belt toward the other side of the pulley body so that the pulley body contacts obliquely with the drive belt, and the length of a belt span between the auto belt alignment pulley and each of adjacent pulleys is set larger than the width of the drive belt.