带压电缆天滑轮密封圈挤出失效分析及结构优化

Extrusion Failure Analysis and Structural Optimization of SealingRing of Pulley under Pressure

针对带压电缆天滑轮在承受作业环境中的超高压时,密封圈被挤出失效而发生泄漏的问题,结合带压滑轮的密封结构、密封原理,通过建立密封结构的有限元分析模型,分析密封圈密封失效的原因,发现密封圈失效的主要原因为,带压滑轮的外壳与内壳体出于加工精度与加工成本的考虑,两者间为间隙配合,再加上在实际工况下因受到介质压力与电缆重力作用,造成内外壳体之间间隙过大,另外为便于装配,密封圈沟槽承压面设置的矩形挡圈与外壳体内壁也有一定间隙,因此造成间隙过大,O形圈无法补偿内外壳体之间产生的间隙,且会在介质压力作用下被挤进间隙中,并且会产生应力集中。针对失效根源提出将矩形挡圈替换为三角形挡圈的优化方案,通过有限元分析得出三角形挡圈能有效补偿内外壳体之间的间隙,防止密封圈发生被挤出损伤。

In response to the problem of leakage caused by the extrusion failure of the sealing ring when the pulley under pressure is subjected to ultra high pressure in the working environment,combining the sealing structure and sealing principle of the sealing pulley,the finite element analysis model of the sealing structure was established,and the cause of the sealing failure was analyzed.It is found that the main reason for the failure of the sealing ring is that the gap between the inner and outer shells is too large,because the outer shell and inner shell of the pulley under pressure are clearance fit due to considerations of machining accuracy and cost,the excessive clearance between the inner and outer shells is produced when subjected to medium pressure and cable weight under actual working conditions,and there is also a certain gap between the rectangular retaining ring set on the pressure bearing surface of the sealing ring groove and the inner wall of the shell for ease of assembly.The O-ring cannot compensate for the larger gap between the inner and outer shells,and it will be squeezed into the gap under the pressure of the medium,and a stress concentration is also produced.An optimization scheme was proposed to replace the rectangular retaining ring with a triangular retaining ring.Through finite element analysis,it is found that the triangular retaining ring can effectively compensate for the gap between the inner and outer shells,preventing the sealing ring from being squeezed out and damaged.