Motorized drive ( 5 , 5" ) configured to open and/or close a wing of a barrier such as a door, main door, gate or swing shutter, a wall or sliding partition or other sliding wing, wherein the motorized drive comprises an electric motor , a first reduction unit ( 9, 9" ) through which the motor can operate the wing opening and/or closing the same, an auxiliary elastic energy motor ; and wherein: - the first reduction unit ( 9, 9" ) comprises a first ( 11 , 11" ) and a second toothed profile ( 13, 13" ) engaging together, thus realizing a gear with a variable transmission ratio depending on the angular and/or linear position of at least one of the two toothed profiles; and - at least one of the first ( 11 , 11" ) and of the second toothed profile ( 13 , 13" ) forms at least one toothed section having a pitch profile which is substantially non-circular or not formed by a simple arc of a circle or a straight line - the elastic energy auxiliary motor comprises a second reduction unit which in turn comprises a first and a second toothed profile engaged together to form a gear; - the first toothed profile of the second reduction unit and the second toothed profile of the first reduction unit are configured to be operated both by the electric motor and by the auxiliary elastic energy motor ; - the motorized drive ( 5, 5" ) is configured for operating the closure of the wing through the second reduction unit characterized in that - the elastic energy auxiliary motor can be connected to the wing through the second reduction unit ; - the first toothed profile of the second reduction unit and the second toothed profile of the first reduction unit are keyed onto the same shaft and/or integrally fixed to one another in such a way that the respective axes of rotation (AX 13) and (AX 11' ) coincide. - the first reduction unit ( 9, 9" ) comprises a first ( 11 , 11" ) and a second toothed profile ( 13, 13" ) engaging together, thus realizing a gear with a variable transmission ratio depending on the angular and/or linear position of at least one of the two toothed profiles; and - at least one of the first ( 11 , 11" ) and of the second toothed profile ( 13 , 13" ) forms at least one toothed section having a pitch profile which is substantially non-circular or not formed by a simple arc of a circle or a straight line - the elastic energy auxiliary motor comprises a second reduction unit which in turn comprises a first and a second toothed profile engaged together to form a gear; - the first toothed profile of the second reduction unit and the second toothed profile of the first reduction unit are configured to be operated both by the electric motor and by the auxiliary elastic energy motor ; - the motorized drive ( 5, 5" ) is configured for operating the closure of the wing through the second reduction unit characterized in that - the elastic energy auxiliary motor can be connected to the wing through the second reduction unit ; - the first toothed profile of the second reduction unit and the second toothed profile of the first reduction unit are keyed onto the same shaft and/or integrally fixed to one another in such a way that the respective axes of rotation (AX 13) and (AX 11' ) coincide. <EOS>