Abstract: The variable speed hydraulic unit has the peculiarity of comprising a fixed body and a rotatable body with hydraulic actuation and fixed displacement, which are operatively interconnected. The output shaft of the fixed body is rigidly associated with the input of the rotatable body in turn operatively associated with a terminal output shaft. A flow divider is furthermore provided for dividing the flow of working fluid fed at a constant flow-rate, having its deliveries connected respectively to the fixed body and to the rotatable body, the percentual distribution between the deliveries determining the direction and speed of rotation of the terminal output shaft.