A variable transmission may include a segmented pulley and a nested pulley located at least partially within the segmented pulley. The spacing between the components of the first segmented pulley may be varied to alter the transmission ratio of the variable transmission by altering the effective diameter of the segmented pulley. The nested pulley may also be a segmented pulley. In some embodiments, one of the pulleys may be rotationally fixed, and the variable transmission may comprise a compact infinitely variable transmission. The eccentricity of the compact infinitely variable transmission may be significantly less than the eccentricity of other infinitely variable transmission designs. In other embodiments, a nested pulley structure may be used to provide a compact continuously variable transmission.

A variable transmission may include a segmented pulley and a nested pulley located at least partially within the segmented pulley. The spacing between the components of the first segmented pulley may be varied to alter the transmission ratio of the variable transmission by altering the effective diameter of the segmented pulley. The nested pulley may also be a segmented pulley. In some embodiments, one of the pulleys may be rotationally fixed, and the variable transmission may comprise a compact infinitely variable transmission. The eccentricity of the compact infinitely variable transmission may be significantly less than the eccentricity of other infinitely variable transmission designs. In other embodiments, a nested pulley structure may be used to provide a compact continuously variable transmission.

A controller for a transmission including a continuously variable transmission mechanism including a primary pulley to which power of an engine is input, a secondary pulley that transmits the power to a drive wheel, and a belt that is wound around the primary pulley and the secondary pulley, increases a rotation speed of the secondary pulley as a torque transmission capacity of a lock-up clutch of a torque converter provided between the engine and the primary pulley increases, and the lock-up clutch is engaged, performs a gear shift process to change a gear ratio of the continuously variable transmission mechanism to a high side or a low side so as to cancel return movement of a drive shaft which has been twisted by the engagement of the lock-up clutch.

A controller for a transmission including a continuously variable transmission mechanism including a primary pulley to which power of an engine is input, a secondary pulley that transmits the power to a drive wheel, and a belt that is wound around the primary pulley and the secondary pulley, increases a rotation speed of the secondary pulley as a torque transmission capacity of a lock-up clutch of a torque converter provided between the engine and the primary pulley increases, and the lock-up clutch is engaged, performs a gear shift process to change a gear ratio of the continuously variable transmission mechanism to a high side or a low side so as to cancel return movement of a drive shaft which has been twisted by the engagement of the lock-up clutch.