Speed-changing excavator

The utility model discloses a speed-changing excavator which comprises an excavator body, a coal mining device and a coal conveying device, wherein the coal mining device comprises a coal cutting device, a cutting arm connected with the coal cutting device and a connecting frame connected with the excavator body; a speed-changing device which is connected with a drive machine and comprises a speed-changing mechanism and a speed-reducing mechanism is arranged between the cutting arm and the connecting frame; a box body and an output shaft of the speed-changing mechanism are connected with a box body and an input shaft of a speed reducer; the speed-changing mechanism is provided with three classes of gear-shifting and speed-changing mechanisms; and the speed-changing device can also be an automatic speed-changing device. The utility model can change the rotating speed of the coal cutting device according to the soft and hard condition of a coal layer, at least realizes three-class speed change, can realize three working states of low speed, normal speed and high speed in a simple structure and greatly improves the application range of the excavator and the working efficiency.