新型井下牵引器步进机构动态特性分析

针对井下牵引器步进机构滚珠丝杠副做运动分析的传统计算方法并未考虑滚动体惯性载荷的问题,采用矢量分析法对滚珠丝杠副进行了运动学分析,得出其轴向运动的影响因素,并运用球轴承拟静力学的分析方法,结合往复作业的实际工况,建立了只受纯轴向力的滚珠丝杠副拟静力学简化分析模型,解出相关影响参数,并研究了不同轴向载荷和转速下步进机构的运动规律。研究结果表明:丝杠轴向移动速度曲线呈现负正弦变化趋势,且转速对其影响显著,轴向载荷一定时,转速与轴向移动速度成倍增长;而对比轴向载荷的影响就略小,一定转速下,在机构的带载能力范围内,随着轴向载荷的递增,轴向移动速度会产生极小的差值;与传统计算方法对比,该轴向速度数值及变化规律有明显的出入。研究结果对于牵引器在水平井井下作业的精确进给和控制具有一定的指导意义。

Dynamic Behavior Analysis on a New Type of Downhole Tractor Stepping Mechanism

The traditional calculation method for the motion analysis of the ball screw pair of the downhole tractor stepping mechanism does not consider the inertial load of the rolling element.The vector analysis method is used to perform a kinematic analysis on the ball screw pair,and the influencing factors of axial direction motion is obtained.Combining the quasi-static analysis method for ball bearings with the actual working conditions of reciprocating operation,a simplified quasi-static analysis model of the ball screw pair subjected to pure axial force is established.The relevant influencing parameters are solved,and the motion law of the stepping mechanism under different axial loads and RPM is studied.The results show that the axial movement speed of the screw shows a negative sinusoidal change,and is significantly influenced by the RPM.When the axial load is constant,the axial movement speed increase linearly with RPM.While the axial load has a smaller effect.Under a given RPM,within the range of the loading capacity of the mechanism,as the axial load increases,the axial movement speed shows a very small difference.Compared with the traditional calculation method,the axial speed and its change law show a significant difference.The study has certain guiding significance for the precise feed and control of the tractor's downhole operation in horizontal wells.