Semi-closed type forging die used for forging of bevel gear and forging method thereof

The invention discloses a semi-closed type forging die used for forging of a bevel gear and a forging method thereof. The die comprises a toothed die, an upper punch, a back cone die and a lower punch, wherein the toothed die and the upper punch are installed in a matched mode; the back cone die and the lower punch are installed in a matched mode; a closed space formed by matching of the toothed die and the back cone die comprises a cavity and a shunting structure located at the big-end part of the toothed die; the shunting structure communicates with the cavity and is a narrow interval; and when the bevel gear is forged, blanks fill the cavity firstly under the action of the upper punch and then are pressed into the shunting structure, so that the filling richness of tooth profiles is ensured. The semi-closed type forging die is of a semi-closed type forging structure, namely the back cone die and the toothed die are closed to form the closed cavity, but the shunting structure is designed on the top of the b