Patent ID: 7166051

Claim:
A speed transmission apparatus, arranged between a drive engine and a drivable receiving device, comprising a rotary casing ( 27 ) arranged so as to be able to turn about an axis of rotation ( 6 ) and to be driven in rotation by the drive engine, thus serving as a driving input for the apparatus, a first epicyclic gear train ( 29 , 31 , 33 , 34 ) and a second epicyclic gear train ( 35 , 31 , 34 , 37 ) which are arranged in said rotary casing, said first and said second epicyclic gear trains forming a double gear train located between said driving input connected to the drive engine and an output shaft ( 32 ) arranged so as to be able to rotate about said axis of rotation ( 6 ) and connected to the drivable receiving device, said double gear train establishing between the driving input and the output shaft a transmission ratio between an input rotation speed and an output rotation speed, the first epicyclic gear train comprising a first sun gear ( 29 ) mounted on an interposed output shaft ( 30 ), so as to rotate therewith, a central gear ( 31 ) mounted on the output shaft ( 32 ) so as to rotate therewith, and first planets ( 33 , 34 ) arranged between the first sun gear ( 29 ) and the central gear ( 31 ) so as to be able to rotate together with at least one pivot shaft ( 41 ) which is parallel to the rotation axis ( 6 ) and which makes a revolution about the latter during rotation of the first casing ( 27 ), the second epicyclic gear train comprising a second sun gear ( 35 ) mounted on a second interposed input shaft ( 36 ), said central gear ( 31 ) mounted on the output shaft ( 32 ) and second planets ( 34 , 37 ) arranged between the second sun gear ( 35 ) and the central gear ( 31 ) so as to be able to rotate together and with the first planets ( 33 , 34 ) and said at least one pivot shaft ( 41 ), a first rotation transmission which is arranged at an intermediate output of the first epicyclic gear train, and which comprises said interposed output shaft ( 30 ) able to rotate about said axis of rotation, a second rotation transmission arranged at an intermediate input of second epicyclic gear train and which comprises said interposed input shaft ( 36 ) able to rotate about said axis of rotation, a first electric motor brake ( 38 ) acting on said interposed output shaft and capable of modifying a speed of rotation thereof, and a second electric motor brake ( 34 ) acting on said interposed input shaft and capable of modifying a speed of rotation thereof, and control means electrically connected to and controlling the first and second motor brakes so as to be able continuously to modify the speed of rotation of said interposed output and input shafts on which the electric motor brakes act and, thus, also the transmission ratio between said input rotation speed and said output rotation speed.