三牙轮钻头运动学仿真模型及其运动特点研究

根据钻头几何学和运动学建立起了随钻运动的三牙轮钻头的计算机运动学仿真模型，该仿真模型既表示出了钻头上各牙齿的形状、大小和在钻头上的分布情况，又可真实反映钻头钻进过程中各牙齿的瞬时位置和相互关系。该研究不但为钻头与岩石互作用仿真建模做好了准备，也是分析研究牙轮钻头工作行为的基础。最后根据所建立的运动学仿真模型建立起了牙轮上发生纯滚动点的曲面方程，并分析了牙轮上各齿圈牙齿的运动特点和钻头的几何结构对牙轮／钻头速比（简称轮头速比）的影响，能更加清楚地认识钻头上各齿圈牙齿的刮削破岩方式；同时把牙轮的运动分解为各个齿圈的运动，也为建立钻头几何结构与轮头速比之间的关系提供了新途径。

Research on Kinematics Simulation Model and Motion Characteristic about Tri-cone Bits

In this paper, the kinematics simulation model of tri-cone bits was established according to the roller cone bit geometry and kinematics. This model could be used to describe not only shape, size and distribution of every tooth on bits, but also their instantaneous location and correlation during work. The model is a basic simulation modeling for interaction simulation between bits and rock, and also for analyzing working model of roller bits. Finally,according to the geometry structure of bits,the motion characteristic of tooth in each row was analyzed, including their scraping mode influenced on the cone/bit ratio. As a result, the relationship was established between geometry structure and the cone/ bit ratio.