Research On Optimization Design Of Cutting Parts Of Rotary Drilling Rig

The cutting parts of rotary drilling rig are composed of the cutting gear and the cutting seat,which often work under high load condition in cutting.Bad working conditions improve the probability of failure of cutting parts: 70% of the failure of the pick seat is caused by weld cracking,especially in areas with bad welding conditions;The failure of the pick tooth is basically due to the wear,fall off,edge collapse,deformation and fracture of the cemented carbide head.In this paper,optimization design is carried out for the failure of cutting parts caused by weld cracking.In view of the failure problem of the carbide head of the pick tooth,the taper PDC tooth was adopted and the impact resistance analysis and cutting analysis were carried out to reduce the probability of the damage of the taper tooth.The research results of this paper mainly include the following aspects:A new type of cutting parts structure has been designed.This structure by introducing a square plate with bolts change tooth and connection between the drill cylinder,is expected to decrease the difficulty of welding in the process of cutting parts installation convenient for cutting vulnerable parts replacement,increase work efficiency of the rotary digging,alpine hypoxia for region of the rotating drill cut tooth replacement with new ideas.The finite element simulation shows that the whole structure including the bolt is within the allowable stress range and conforms to the strength criterion.After the field test,the main body of the new structure is feasible without damage.Some bolts are deformed,and the bolt design needs to increase the strength.The tangential impact resistance of large taper PDC teeth was analyzed,and the influence of matrix diameter on impact resistance of taper teeth was studied.According to the results of previous experiments,the control group and experimental group were determined and the impact analysis scheme was designed.The scheme is divided into simulation part and field test part.Simulation analysis shows that the tangential impact resistance of D20 series cones is better than that of D14.Field tests verify that the fracture impact energy range of D20 series PDC teeth with cone Angle of 68° is 1200J-1800 J.It is estimated that the fracture impact energy of D20 series PDC teeth with cone Angle of 71° is 1200 J,and that of D20 series PDC teeth with cone Angle of 74° is 855 J.The results show that increasing the matrix diameter can greatly improve the tangential impact resistance of conical PDC teeth.The conical PDC teeth were analyzed and the application conditions of different specifications of cone teeth were evaluated.Finite element analysis shows that the cutting area,cutting resistance and cutting surface stress of D20 series are greater than those of D14 series,and the cutting difficulty increases with the increase of cone Angle in the same series.Field tests show that the wear circle area of D14 cone teeth is 2.89mm2 and the maximum radius is 1.13 mm.The wear circle area of D20 cone teeth is 9.35mm2 and the maximum radius is 2.69 mm.Generally speaking,when cutting and breaking rock in uniform strata,the cutting resistance is the main factor affecting the life of cone teeth,and it is more appropriate to apply small-size cone PDC teeth.In the construction of uneven rock strata,tangential impact force is the main factor affecting the life of cone teeth,so it is more suitable to apply large cone PDC teeth.