Planetary gear transmission with variable ratio

A planetary gear transmission with a variable transmission ratio, without a ring gear wheel, including:

• a first sun gear arranged on a first operating shaft and at least one first planetary gear connectable thereto;
• a second sun gear arranged on a second operating shaft and at least one second planetary gear connectable thereto;
• planetary shafts rigidly attaching each of the second planetary gears to one of the first planetary gears, in which case the first and second planetary gears form first planetary gear pairs, where the planetary gears rotate at the same angular velocity;
• and
• a planetary carrier common to the first and second planetary gears;
• the planetary gear transmission comprising, as a combination:
• at least one coupling means for taking out at least some rotary force from the planetary gear transmission, and/or for feeding the rotary force into the planetary gear transmission, via said first or second operating shaft, or via the planetary carrier;
• and
• at least one operation means for controlling the rotation velocity of the planetary carrier at least to a first mode, where the planetary carrier is locked to be stationary, and to a second mode, where the planetary carrier is freely rotatable
• a coupling transmission with:
• first and second axle gears thereof attached to said first operating shaft and to the second operating shaft respectively;
• and
• an actuating shaft and a running shaft thereof provided with movable first and second shifting gears, which are alternatively connectable to the first and second axle gears, in order to change the first operating shaft of the planetary gear transmission to operate with the actuating shaft or with the running shaft, and respectively in order to change the second operating shaft to operate with the running shaft or with the actuating shaft and vice versa.