旋转导向工具多列块式滑动轴承载荷研究

Load Characteristics of Multi-Row Block Sliding Bearing for Rotary Steerable System

多列块式径向滑动轴承是推靠式旋转导向工具轴承系统新近采用的一种轴承形式。为了研究近钻头端径向滑动轴承摩擦副的载荷特性,采用Augmented Lagrange摩擦接触非线性算法,考虑旋转导向工具几何非线性效应,利用ANSYS Workbench软件,进行了滑动轴承各列摩擦块的力学分析。对钻头压力为200 kN、翼肋推力分别为10和25 kN的2种载荷工况下摩擦副应力分析结果表明:选用材料满足载荷工况强度要求;轴承内、外圈各列摩擦块的最大应力分布以半周分界呈现2种变化规律,近翼肋和近钻头的2列摩擦块应力水平及分布受外载荷影响较大,近钻头列摩擦副的载荷明显高于其他3列;翼肋推力的增大导致内圈各列摩擦块在2种载荷工况下的最大应力比值达6倍以上,远高于外圈摩擦块,使内、外圈摩擦块的最高应力水平接近相等;轴承内圈近翼肋和近钻头的两列摩擦块在工作中承受较高应力幅的周期性交变载荷,易发生疲劳破坏。研究结果为推靠式旋转导向工具多列块式滑动轴承的设计与合理使用提供了理论支持。

Multi-row block radial sliding bearing is a new type of bearing used in the bearing system of push-the-bit rotary steerable system.In order to investigate the load characteristics of the friction pair of radial sliding bearing near the drill bit,considering the geometric nonlinear effect of rotary steerable system,the mechanical analysis was conducted for each row of friction blocks of radial sliding bearing by using the ANSYS Workbench software with Augmented Lagrange friction contact nonlinear algorithm.The stress on the friction pairs was analyzed under two load conditions,that is,the bit pressure is 200 kN and the rib pushing force is 10 kN and 25 kN,respectively.The results show that the material meets the strength requirements under load conditions.The maximum stress distribution of each row of friction blocks in the inner and outer rings of the bearing presents two kinds of variation rules with half circle as the boundary.The stress levels and distributions of two rows of friction blocks near the rib and near the bit are greatly affected by the external load,and the load of the friction pair in the row near the bit is obviously higher than that of other 3 rows.As the rib pushing force increases,the maximum stress ratio of each row of friction blocks in the inner ring under two load conditions is more than 6 times,which is much higher than that of the friction blocks in the outer ring.As a result,the maximum stress values of friction blocks in the inner and outer rings are nearly equal.The two rows of friction blocks near the rib and the bit in the bearing inner ring bear the periodic alternating load with high stress,prone to fatigue failure.The results provide theoretical support for the design and rational use of multi-row block sliding bearing for the push-the-bit rotary steerable system.