中文摘要：

针对螺杆钻具推力轴承易失效的问题，根据Hertz接触理论，利用有限元数值模拟技术建立了推力轴承接触模型，分析了多层向心推力球轴承的力学及运动特性。分析结果表明，螺杆钻具多列向心推力球轴承能有效地分担轴向载荷，每层轴承的各个滚球受力相对均匀；轴承上、下两端的内圈、外圈及滚球所承受的载荷较大，最容易破碎，建议两端使用更高性能材料，以延长推力轴承整体寿命；推力轴承每层滚球运动规律基本一致，外圈与滚球之间以滚动摩擦为主，而内圈与滚球之间存在滚动与滑动的复合摩擦，因此内圈的磨损更为严重。该项研究成果揭示了螺杆钻具推力轴承的承载特性及运动规律，为推力轴承的失效分析及结构改进提供了理论依据。

英文摘要：

The thrust bearing of screw drill is easy to fail. Therefore, according to Hertz contact theory, finite el- ement numerical simulation technology was applied to establish the contact model of thrust bearing. The mechanical and kinetic properties of multilayer centripetal thrust ball bearing were analyzed. The analysis shows that the multi- column centripetal thrust ball bearing of screw drill can effectively share axial load. The force of the bearing roiling balls of each layer is relatively even. The load of the inner ring, outer ring and rolling ball on the upper and lower ends of the bearing is relatively large. Thus, they are easy to crush. It is suggested that material of higher perform- ance should be used for both ends in order to lengthen the overall service life of thrust bearing. The motion law of the rolling balls of each layer is basically similar. Rolling friction exists between outer ring and rolling ball while composite friction of roiling and sliding exists between inner ring and rolling ball. Therefore, the damage to inner ring is more serious. The research findings disclose the loading property and motion law of the bearing, providing the theoretical basis for the failure analysis and structural modification of thrust bearing.