Patent ID: 7163476

Claim:
A belt type continuously variable transmission comprising a variable width drive pulley, a variable width driven pulley, and a V belt, which is disposed around said drive and driven pulleys; wherein: a contour of a contact surface being in contact with said V belt in a cross-sectional view through axes of said drive and driven pulleys is an arc that has a first radius of curvature rp and is convex to said V belt; a contour of a contact surface being in contact with said drive and driven pulleys in a cross-sectional view perpendicular to a longitudinal direction of said V belt is an arc that has a second radius of curvature re and is convex to the contact surface of said drive and driven pulleys; and a contact point moving on the contact surfaces of said drive and driven pulleys and said V belt for a speed ratio change satisfies the following equation: Δ le/Δlp=re/rp the Δlp being a distance over which said contact point migrates in the cross-sectional view through the axes of said drive and driven pulleys, and the Δle being a distance over which said contact point migrates in the cross-sectional view perpendicular to the longitudinal direction of said V belt, wherein the center Op of the arc having said first radius of curvature rp, which forms the contact surface in contact with said V belt in the cross-sectional view through the axes of said drive and driven pulleys, is positioned away from the axes of said drive and driven pulleys, and wherein said center Op is positioned on another side across the axes of said drive and driven pulleys opposite to a side of the contact surface in contact with said V belt.