CVT Mechanical Description

Continuously variable transaxle (CVT) can vary the actual gear ratio continuously and stepless from low-speed to high-speed range depending on the driving conditions. The CVT allows an improved driveability with reduced shift-shock in comparison with an existing A/T (Automatic Transaxle).

This transaxle is an electronic control fully automatic transaxle with forward continuously variable and reverse 1-speed.

The torque converter is a 3-element, 1-step and 2-phase type and is equipped with an automatically controlled lock-up mechanism.

The gear change device consists of a ravigneaux type planetary gear unit, multiple disc type clutch, multiple disc type brake, steel belt, primary pulley and secondary pulley.

The hydraulic pressure control device consists of a valve body assembly, line pressure control solenoid valve (linear solenoid), secondary pressure control solenoid valve (linear solenoid), TCC solenoid valve (linear solenoid) and lock-up/select switching solenoid valve. Optimum line pressure complying with engine torque is produced by the pressure control solenoid valves in dependence upon control signal from TCM. This makes it possible to control the line pressure with high accuracy in accordance with the engine power and running conditions to achieve smooth shifting characteristics and high efficiency.

The TCM can change the dimension between the two pulley surfaces. To continuously vary its gear ratio, the TCM simultaneously adjusts the diameter of the primary pulley that transmits torque from engine and the secondary pulley that transfers torque to the wheels. With continuously shifting of gear ratio, the CVT can avoid the shift-shock and deliver smooth driving.