Influence of the Band Spring Pressure on the Contact Load in the Shaft–Seal Connection

Abstract

Reinforced rubber lip seals are used in bearing assemblies. Their reliable operation is ensured by pressing the lip of the seal against the shaft. The produced contact load prevents the outflow of sealed medium and the penetration of an abrasive and of chemically aggressive substances into the assembly, which reduces the service life of the parts. The contact load in the connection is affected by the force generated by the band spring. The method presented here is used to determine the specific contact load of the seal lip on the shaft imposed by the band spring depending on the parameters of the lip seals and springs. To check the adequacy of the methodology, the authors studied a batch of twenty five 1.1-45x65-1 reinforced lip seals (GOST 8752-79). The theoretically calculated contact force exerted by the spring was 2.64 to 3.804 N, specific contact loads were 0.098 to 0.153 N/mm while those according to experimental data were 2.75 to 3.50 N and 0.102 to 0.141 N/mm, respectively. High convergence confirms the correctness of the presented calculated relationships. It was established that the parameters of the lip seals had a large spread, which hampered accurate calculation of the specific load in the shaft–seal connection. To increase the accuracy of readings, it is necessary to reduce the tolerances on the dimensions of rubber products.