关键词: 牙轮钻头, 运动学, 钻头设计, CAD分析方法

Abstract: Tooth-row arrangement is an important part of rock bit design,and has great effects on bit performance.Based on rock bit kinematics,the relationships between tooth-row arrangement and bottomhole breakage are studied,a new method of tooth-row arrangement design anslysis is established in this paper.On the basis of analyzing tooth trajectory,the scraping distance and velocity of every tooth-row is calculated.According to the outline formed by the radial trajectory of every tooth-row,the bottomhole radial breakage chart is given,which improves the traditional bottom coverage layout and can audio-visually reflect the effects of cone offset and tooth radial scraping distance on bottomhole breakage.A new delimitation method of bottomhole breakage annuluses and the calculation method of cutting volume per tooth are set up.It is shown that cutting volume per tooth should be as well-distributed as possilbe in bit design.

Key words: rock bit, kinematics, bit design, CAD, analytical method