The invention relates to a planetary gear two-
gear transmission and a working method thereof.The planetary gear two-
gear transmission comprises a transmission shell, a planetary
gear transmission mechanism arranged in the transmission shell, a normally-closed
clutch and a first
actuator driving the normally-closed
clutch, a top disc is arranged on the right side of the normally-closed
clutch, and the top disc is in transmission connection with the normally-closed clutch in the axial sliding and rotating direction; the right end of the top disc is slidably connected with a gear ring on the periphery of the planetary gear transmission mechanism, and a
brake concave part is arranged on the periphery of the left end of the top disc. A braking device is arranged on the transmission shell and comprises a braking block, the braking block is driven by a second
actuator to move in the direction perpendicular to the axis of the transmission to be wedged into the braking concave part, and the first
actuator and the second actuator share the same power. According to the invention, the
advantage of smooth and rapid power-interruption-free gear shifting of the planetary gear can be better exerted, the phenomenon of'locking '
chip burning caused by simultaneous combination of the two clutches is avoided, and the problem of power interruption caused by simultaneous separation of the two clutches can also be avoided.