Large rock breaking hob bit

The utility model discloses a large rock breaking hob bit which comprises a rotary disc located below a drill rod, a pilot cylinder is arranged in the middle of the lower surface of the rotary disc ina protruding mode, and a plurality of first cone hobs are arranged on the bottom ring face of the pilot cylinder. An annular face is formed on the lower surface of the rotary disc on the outer edge of the pilot cylinder, a plurality of wheel carriers are arranged on the annular face of the rotary disc, each wheel carrier is connected with a circular truncated cone hob through a shaft, and an acute angle is formed between the shaft of each circular truncated cone hob and the vertical direction. The large rock breaking hob bit is high in drilling efficiency and good in guidance quality. 本实用新型公开了一种大型破岩滚刀钻头，它包括位于钻杆下方的转盘，转盘下表面中部凸有先导筒，先导筒底环面设有多个第一牙轮滚刀；先导筒外沿的转盘下表面形成环面，转盘环面设有多个轮架，每个轮架经一根轴连接有一个圆台体滚刀，且每个圆台体滚刀的轴与竖直向呈锐角。该大型破岩滚刀钻头钻进效率高且导向性好。