Patent ID: 7547254

Claim:
A drive shaft for All-Terrain Vehicles (ATVs) which is installed in a mounted type vehicle designed to traverse uneven terrains and which transmits drive power to front wheels through a constant velocity joint on an inboard side and a constant velocity joint on an outboard side, wherein a boot for at least the outboard side constant velocity joint is made of chloroprene rubber whose hardness, in terms of JISK6253 Durometer Hardness A Type, is 65 or less at normal temperature (25° C.) and is 77 or less at low temperature (−20° C.), and wherein the constant velocity joint on the outboard side comprises: an outer ring having a plurality of axially extending track grooves disposed circumferentially of an inner spherical surface, an inner ring having a plurality of axially extending track grooves disposed circumferentially of an outer spherical surface, torque transmitting balls which engage the track grooves of the outer and inner rings, and a cage interposed between the inner spherical surface of the outer ring and the outer spherical surface of the inner ring and having pockets for receiving the torque transmitting balls, wherein a groove center of the track grooves of the outer ring and a groove center of the track grooves of the inner ring are axially offset by equal spacings in mutually opposite directions on opposite sides of a joint center, as viewed in a longitudinal joint section, wherein a track groove offset angle between 4° and 6° is defined between the groove center of either the track groove of the outer ring or the track groove of the inner ring, a center of the torque transmitting ball, and the joint center, and wherein an opening-side end of the track grooves of the outer ring is provided with a straight section, and an opposite opening-side end of the track grooves of the inner ring is provided with a straight section.