Step-up gear box for wind power generator

The invention belongs to the field of mechanical transmission, and relates to a step-up gear box, in particular to a step-up gear box for wind power generation. A connecting flange of the step-up gear box is in interference with a front half section of a planetary carrier through a spline; cylindrical matching faces are in interference connection with each other to transmit loads; the cylindrical faces are in interference connection with each other, so that a spline pair is not influenced by a bending moment, and only a torque is transmitted; the spline pair adopts the interference connection, so that the problem that adverse factors such as opposite friction among keys and teeth influence the service life of the spline is solved during power transmission; a planetary gear train adopts a composite planetary gear train, so that the weight of the gear box is reduced, the quantity of bearings is reduced, and the processing and manufacturing costs of the gear box are lowered; the quantity of gear meshing pairs is reduced; and the transmission efficiency of the gear box is improved greatly.