Abstract: The reciprocating seal is a kind of commonly used seal forms. The mechanism of reciprocating seals under thin film lubrication state was researched. The various factors were considered and the computing formulas of leak quantity and friction coefficient were deduced. An actual example and its computing result were given，and the change trends were analyzed. The research result provides necessary foundations for applications of thin film lubrication seals.

Key words: Thin film lubrication, Reciprocating seal, Calculation

摘要： 往复式密封是密封技术中常用的密封形式，研究薄膜润滑条件下往复式密封的机理，考虑到各种因素，推导泄漏量、摩擦系数的计算公式，进行实例计算，给出计算结果并分析了变化趋势，为薄膜润滑密封的应用提供了十分必要的依据。

关键词: 薄膜润滑, 往复式密封, 计算