Continuously variable transmission

A continuously variable transmission comprising:

• a first pulley including a first fixed sheave that is fixed to a first rotating shaft and a first movable sheave that rotates integrally with the first rotating shaft and is movable along the first rotating shaft, the first pulley being configured such that power from a power source mounted in a vehicle is transmitted to the first pulley through the first rotating shaft;
• a first thrust-force generating device configured to generate a thrust force that pushes the first movable sheave toward the first fixed sheave;
• a second pulley including a second fixed sheave that is fixed to a second rotating shaft and a second movable sheave that rotates integrally with the second rotating shaft and is movable along the second rotating shaft, the second pulley being configured to transmit power to a drive wheel of the vehicle through the second rotating shaft;
• a second thrust-force generating device configured to generate a thrust force that pushes the second movable sheave toward the second fixed sheave;
• and
• a transmission belt configured to transmit power by being wrapped around a first belt wrapping groove formed in the first pulley by tapered surfaces, facing each other, of the first fixed sheave and the first movable sheave and around a second belt wrapping groove formed in the second pulley by tapered surfaces, facing each other, of the second fixed sheave and the second movable sheave,
• wherein the continuously variable transmission is configured to steplessly change a gear ratio within a range between a maximum gear ratio and a minimum gear ratio by continuously changing a width of the first belt wrapping groove and a width of the second belt wrapping groove,
• wherein, in a belt track for the transmission belt to run on at the minimum gear ratio, a coefficient of friction of each of the tapered surfaces of the first fixed sheave and the first movable sheave relative to the transmission belt at a portion in contact with the transmission belt is lower than a coefficient of friction of each of the tapered surfaces of the second fixed sheave and the second movable sheave at a portion in contact with the transmission belt, and
• wherein a coefficient of friction of each of the tapered surfaces of the second fixed sheave and the second movable sheave relative to the transmission belt at a radially inner portion is higher than a coefficient of friction of each of the tapered surfaces of the second fixed sheave and the second movable sheave relative to the transmission belt at a radially outer portion.