Study of the Influence of Macrogeometry Parameters on the Tightness of Shaft–Seal Joints

Abstract

The factors influencing the reliability and durability of the joint between a shaft and a rubber reinforced seal are analyzed. It has been established that the theory of tightness of such joints has not yet been developed. The quality of a joint is usually assessed by the amount of leakage. It has been revealed that the amount of leakage depends on the materials from which the shaft and seal are manufactured, the roughness of the shaft surface, the presence of dust in the friction zone, the quality of the sealed liquid, and the operating temperature. In addition, the durability of the work is influenced by macrogeometry parameters like deviation from the perpendicularity of the seal to the shaft, deviation from coaxiality, and radial runout of the shaft. A multifactorial experiment has been carried out, as a result of which an empirical relationship has been established between the radial runout of the shaft, rotational speed, and interference in the joint according to the criterion of the onset of leaks. Analysis of the obtained dependence showed that the radial runout should be compensated by interference in the joint, and with an increase in the rotation speed, the compensation value should be greater due to the fact that the working edge of the seal does not have time to follow the shaft. An empirical relationship between the amount of interference and leakage has been obtained, which indicates that with lower interference, leakage will be greater. The research results can be used at the stage of designing assembly units with seals to reduce the influence of radial runout and deviations from the coaxiality of the shaft relative to the seal.