Conclusions on the lubrication conditions in the sealing gap of rod seals can be drawn by measuring the oil film thickness on the rod after outstroke, for which ellipsometry is used in this paper. A commercially available U-cup rod seal made of polyurethane and a polished, hard-chrome-plated hydraulic rod were used. The film thickness was measured at various rod speeds (5–800 mms⁻¹), operating pressures (up to 25 MPa) and oil viscosities (ISO VG 15 - 460). Discrepancies between the inverse theory of hydrodynamic lubrication (IHL) and empirically measured film thickness are discussed in this paper. An approximation equation to calculate the film thickness of the analyzed sealing system based on the presented measurement data is provided.

杆密封件密封间隙的润滑条件可以通过测量外冲后杆上的油膜厚度得出，本文采用椭偏测量法。使用了由聚氨酯制成的市售 U 杯杆密封件和抛光的镀硬铬液压杆。在各种棒速（5-800 mms ^-1）、操作压力（高达 25 MPa）和油粘度（ISO VG 15 - 460）下测量薄膜厚度。本文讨论了流体动力润滑 (IHL) 的逆理论与经验测量的油膜厚度之间的差异。提供了一个近似方程，用于根据所提供的测量数据计算所分析的密封系统的膜厚。