METHOD OF DETERMINING WHEN A CRITICAL FILM THICKNESS WILL BE REACHED IN A GREASE-LUBRICATED SEAL

摘要

The present invention provides a method of determining a time, tc, at which an oil film separating a sliding contact interface (130) between a counterface and an axial lip (115) of a seal will reach a critical film thickness. One of the axial lip and the counterface is provided on a rotational part (125) of the seal and the other of the axial lip and the counterface is provided on a non-rotational part (110) of the seal. Further, the seal is grease lubricated and the oil film is formed by base oil, which bleeds from a grease reservoir (140) on the rotational part of the seal and which flows towards the contact interface (130) under the action of centrifugal force. According to the invention, the method comprises steps of - determining a rotational speed of the rotational part of the seal, - determining a viscosity of the base oil, - determining the time, tc, based on the rotational speed, the viscosity of - the base oil, a cross-sectional area of the grease reservoir and a diameter of the contact interface.