Speed transforming transmission device of drilling machine

The utility model discloses a speed transforming transmission device of a drilling machine. The device comprises a gear box body, wherein an input shaft, a transition shaft, an output shaft and a shifting fork are arranged in the gear box body; two driving gear wheels on the input shaft are respectively meshed with three transition gear wheels on the transition shaft; the transition gear wheels on the transition shaft are respectively meshed with two driven gear wheels on the output shaft, so that the output shaft has the four-shift revolving speed; two reverse gear wheels are arranged on a reversing shaft; one reversing gear wheel can be meshed with the driving gear wheels, and the other reversing gear wheel can be meshed with the transition gear wheels; and the driven gear wheels can be driven by the transition gear wheels to drive the output shaft to rotate reversely. In the speed transforming transmission device of the drilling machine, the output shaft has four positive rotating shifts and reversing shifts; the chosen speed range is wider in the drilling construction, so that the requirement of field construction can be met; and a sub-power winch rotating shaft is arranged in the gear box body; therefore, a winch can be directly driven by the winch rotating shaft to rotate.