三牙轮钻头轮体速比仿真模型研究

三牙轮钻头轮体速比对进行仿真研究，指导钻头结构设计、钻头选型等都起着关键性的作用。从理论上分析了三牙轮钻头的几何结构与牙齿受力的关系，确定牙轮存在一个主动齿圈，并结合最小功原理建立了求解轮体速比的模型，结合钻压以及岩石性质对轮体速比的影响，对该模型进行了修正。将钻头钻进砂岩时的台架试验牙轮/钻头速比实验值和利用模型计算所得牙轮/钻头速比计算值进行了对比，结果表明，该仿真模型能够有效地预测三牙轮钻头的轮体速比。

Research on cone/bit speed ratio simulation model of tri-cone bits

The cone/bit speed ratio of tri-cone bits play an important role in conduction simulation research, directing drill bits design and selection. Theoretically, the correlation of the geometrical structure of and the load on teeth of the bits is analyzed. It is determined that there is a driving tooth row on the roller cone. A computer simulation model is established based on the minimum power theory. Subsequently, the model is modified because of the influence of bit load and rock properties on ratio. Finally, the experiment of drilling is conducted to measure the actual value of the cone/bit speed ratio when the rock bits break sand rock, and the computer simulation model is used to compute the cone/bit speed ratio of the same bits. The simulation results are compared with the experimental data. Results show that the simulation model can be used to compute the cone/bit speed ratio accurately.