Power transmission device and process implementing such device

Process for a transmission of power between a shaft of an engine and a shaft of wheels implementing,

• two electric machines, and
• a mechanical assembly connecting with each other shafts of the two electric machines, the shaft of the engine, and the shaft of the wheels, the mechanical assembly comprising at least two epicycloids gear trains, the at least two epicycloidal gear trains comprising each three element which mesh reciprocally, and in which:
• the shaft of the first machine is connected to an element of one of the epicycloidal gear trains and the shaft of the second machine is connected to the shaft of the wheels, in a first mode of operation,
• the shaft of the first machine is connected to the element of one of the epicycloidal gear trains and the shaft of the second machine is connected to another element of one of the epicycloidal gear trains, in a second mode of operation,
• wherein
• in a third mode of operation, the shaft of the first machine is connected directly to the shaft of the engine and the shaft of the second machine is connected to said another element.