中文摘要：

国内有关高造斜率井眼轨迹控制工具上、下两端轴承的研究主要是对主轴进行偏置试验，忽略了一些实际情况。为此，通过井下工具动态测试台架模拟了井下工况，针对滚针轴承的破坏失效进行了整体理论和有限元分析。依据井眼轨迹控制工具的原理，建立了旋转心轴的力学和数学模型，同时依据所得的主轴和滚针轴承数据，用Solidworks建立了它们的全尺寸仿真模型。分析结果表明，主轴在滚针轴承处的偏斜角度为0．0725°，滚针轴承要阻止轴的弯曲变形，在运行中主轴会给滚子施加一个向左的力；在试验中滚子的倾斜角度达到了0．0293°，这使滚针轴承的使用疲劳寿命急剧缩短。建议对井眼轨迹控制工具的结构进行改进，采用滚针和角接触球组合轴承，使得它能同时承受径向和轴向载荷，延长轴承的使用寿命。

英文摘要：

Domestic researches related to bearings on top and bottom ends of borehote trajectory control de- vices in highly deviated wells are mostly concentrated on offset tests of principal shaft with certain actual conditions neglected. In this regard, testing devices for dynamic performances of downhole tools have been deployed to simu- late in-situ conditions. In addition, overall theoretical and finite-element analyses have been performed for damages and failures of needle bearing. With consideration to working principles of borehole trajectory control tools, me- chanical and mathematic models for the rotating shafts have been constructed. Moreover, by using data related to the principal shaft and needle bearing, SolidWorks is deployed to construct full-sized simulation models for these elements. Relevant results show that the principal shaft may deviate at 0. 072 5° around the needle bearing, where-as the needle bearing may restrict curvature and deformation of the shaft. Consequently, the principal shaft may in-flect a leftward force on the roller during operation. During the test, it was found that the roller deviated up to 0. 029 3°, which may significantly reduce service life of the needle bearing due to fatigue. It is proposed to adopt certain improvements in structure of borehole trajectory-control devices. Through adoption of combined bearing with rollers and angular contact balls, the assembly may ensure bearing both radial and axial loads to prolong service life of the bearing.