Leakage Control Mechanisms and Strategies for Hydraulically Driven Controllable Rod Seals

Abstract

The primary function of rod seals in hydraulic systems is to prevent the leakage of the hydraulic medium, which would otherwise result in environmental pollution and the loss of energy. However, the leakage control performance of conventional rod seals is limited by the level of product design. As a result, the performance of these seals will gradually degrade during the service process. Furthermore, it is not possible to adaptively adjust the performance of these seals in response to changes in operating conditions. Hydraulically controllable rod seals (HCRS) can be driven hydraulically to adjust the internal stress distribution of the seal to regulate the sealing performance. This may be an effective solution, although the leakage control mechanism and strategy remain unclear. This paper employs a thermoelastohydrodynamic mixed lubrication model to comparatively analyze the behaviors and performances of the HCRS with or without a cavity structure. The leakage control mechanism of the HCRS is revealed, namely that it is achieved by increasing the interface contact pressure and reducing the fluid film thickness through external pressurization. Furthermore, the functional relationship between the sealing performance and the regulating variables under different operating conditions is obtained through multivariate regression analysis, thereby forming the quantitative leakage control strategy of the HCRS.