Dynamic model of roller bit with nine degrees of freedom;

Computer simulation for the side-cutting of roller bits;

Model to determine rock drillability by roller bit;

The calculation of contact stress of rock bit floating ring journal bearing under disalignment;

Application of computer simulating technology in rock bit floating-ring journal bearings;

The coupling function analysis of the thread-locking ring of rock bit on axial load;

There are many causes inducing rock bit cone break, in which the effect of its machining on the cone is more serious.