Rock Breaking Mechanism And Experimental Research Of Rotary Cutting Bit

In order to improve the drilling speed and service life of bit, a lot of research has been carried out by domestic and foreign experts and scholars. Based on the analysis of rock breaking for various types of drill bits, the results show that the low efficiency of rock breaking exists in most drill bits. To solve the problem, a new type of drill bit (called rotary-cutting bit) is proposed in this paper, the following research on the swirling cutting bit has been carried out using mathematics, mechanics, computer programming, experiments and other methods.Structure design of swirling cutting bit and establishment of coordinate system are introduced. The performance characteristics of the drill are analyzed. Therefore, the rotary-cutting method of the rotary-cutting bit has high rock-breaking efficiency of drill center, good effect on gage protection, high ROP (Rate of Penetration), improved working condition of bearings, uniform cutter wear and long service life of bit.A kinetics analysis model of the rotary-cutting bit cutter is established, which provides a theoretical basis for the rock-breaking analysis of the cutter. And the main focus of the research is to establish the component model of radial, tangential and vertical velocity, and acceleration.According to the kinematics model, through the modern design methods, such as computer programming, the different parameters in the kinematic model are studied in detail, at the same time, according to the establishment of the kinematic model, the influence of the key parameters (such as ?, s, gear ring, different cutting performance, etc.) on the movement behavior of bit is analyzed. The curves and conclusions of the key parameters are obtained, providing a theoretical basis for the structure design and performance optimization of the rotary-cutting bit. When ? is 30 angle, s is 10mm, and the wheel speed ratio is 0.46, the cutters of the rotary-cutting bit will gradually cover the whole bottom of well, which is conducive to improve the rock-breaking efficiency and all the gear rings can realize the function of cutting well wall at the same time.According to the above analysis results and optimal parameters with the specific working conditions, the rock-breaking characteristics of the different gear rings are analyzed based on the kinematics model of the cutters in the paper. At the same time, based on the above research, the dynamics model of the rotary-cutting bit is established. On this basis, a theoretical model of a rotary-cutting bit that breaks rock is established, and the rock-breaking mechanism of the different gear rings is further analyzed. So the cutters of the rotary-cutting bit can realize the effect from the inside out and the bottom up, and in the rock-breaking process, the tangential cutting is the main factor for rock breaking, the impact force of the center gear rings is relatively large, the rock-breaking efficiency is relatively high, and the wear of the gear ring 1 is the most serious.The experimental study on the rotary-cutting bit is carried out, different types of drill bits in the respects of the bottom hole model, rock debris, drilling pressure and torque, drilling pressure and ROP, and the rock-breaking and wear of the rotary-cutting bit are studied in detail, this experiment provides a theoretical basis for the research on the rock-breaking mechanism of the rotary-cutting bit and the failure mechanism of the cutters.In summary, this paper focuses on the structure design and coordinate system of the rotary-cutting bit; the kinematic model of the rotary-cutting bit is established, and the different parameters in the kinematic model are analyzed; the research on the rock-breaking mechanism of the rotary-cutting bit is carried out. Based on the kinematics model, dynamics model and rock-breaking theory model, the rock-breaking mechanism of the rotary-cutting bit is carried out. Based on the theoretical research, the experiment verifies the accuracy of the theoretical model, which provides some reference for the perfection of the rock-breaking theory system of drill bits.