In a device and a method for operating a driven axle in a machine tool, in particular in an injection-molding machine, at least two different drives are coupled to form a common effective drive, wherein the performance and energy consumption data for each drive are stored in the form of characteristic values or characteristic curves. To use the effective drive as optimally as possible in terms of energy, it is proposed to determine the performance requirement for the driven axle, to determine the particular operational combination of the different drives that requires the least expenditure of energy based on the determined performance requirement and to drive the drives with the determined particular operational combination.