Continuously variable transmission with control of switching between forward and reverse

A continuously variable transmission system for speed change of rotation received from an engine output shaft and for transmitting that rotation, at the changed speed, to vehicle wheels, said system comprising:

• an input shaft for receiving engine torque from the engine output shaft;
• an output shaft for outputting torque to the vehicle wheels;
• a belt type continuously variable transmission unit having a first pulley for receiving engine torque from said input shaft, a second pulley, a belt trained around both of said first and second pulleys and axial force actuating means for changing the pulley ratio of said first and second pulleys by applying axial forces to said first and second pulleys;
• a planetary gear unit having a first rotary element rotatable with said input shaft, a second rotary element rotatable with said second pulley and a third rotary element rotatable with said output shaft;
• selection means for selecting between forward travel wherein torque is transmitted from said second pulley to said first pulley with forward rotation output at said output shaft and reverse travel wherein torque is transmitted from said first pulley to said second pulley with reverse rotation output at said output shaft;
• control means for controlling said axial force actuating means so that axial forces acting on said first and second pulleys produce a difference corresponding to the pulley ratio of said first and second pulleys;
• and
• switching means, responsive to operation of said selection means selecting between said forward travel and said reverse travel, for reversing relative magnitudes of the axial forces acting on said first and second pulleys, under control of said control means, thereby switching between said forward travel and said reverse travel.