The roller bit acts on the bottom hole rock jointly by a vertical indentation and a level shave shear during the rotary drilling. For its analysis, this paper establishes a prediction model for the rate of penetration based on the revolving indentation theory of the roller bit, and through the laboratory tests, obtains the influence coefficient for rock breaking caused by the chisel teeth true rolling pluridentate linkage. The prediction error for the rate of penetration is 4.1% in average. The model provides a theoretical basis for the accurate prediction of the rate of penetration of the roller bit in the rotary drilling. It is concluded that, taking the level shave shear force into consideration, the intrusive depth of the roller bit is increased as compared with the case of only vertical pressing. The difference is smaller for the case of small frictional coefficient and cutting tip angle. However, it becomes greater with the increase of the frictional coefficient and cutting tip angle, so the effect of the horizontal scrapping cannot be ignored.

roller bit  /  revolving indentation  /  rate of penetration  /  level shave shear force  /  shearing breakup