Gear box ratio change controlling device for motor vehicle, has reversible planetary gearset provided for kinematical connection between shafts, and activated in reverse direction for positioning engagement control unit

摘要

The device has a speed reducer comprising a reversible planetary gearset (3) for kinematical connection between primary and secondary shafts (32, 34). The shaft (32) is rotatively connected to a control motor (30), and the shaft (34) drives an engagement control unit. The gearset is activated in a reverse direction, from a gear box, for positioning the control unit, in absence of torque on the motor (30).