RADIAL CAPILLARY SEAL FOR FLUID DYNAMIC BEARING MOTORS

摘要

A seal whose primary axis lies in the radial direction where the fluid bearing is primarily extending in the axial direction between the rotating shaft and surrounding sleeve. The capillary seal is positioned with an opening adjacent an end of the fluid bearing gap, and comprises two diverging walls, with the narrowest gap between the two generally radially extending walls being closely adjacent an end of the fluid gap. The walls diverge as they extend radially away from the fluid bearing. In this way, the fluid held in the radial capillary seal is maintained adjacent an end of the gap, while the size of the reservoir provided or defined by the diverging walls provides a relatively large reservoir volume. The seal uses an additional capillary which is defined by a narrow annulus between the rotating shaft and a radially inward end of one of the two walls of the seal adjacent the narrow end of the radial capillary seal. This very narrow gap provides a narrow annulus which establishes very high shock resistance to the loss of fluid past the outer axial wall of the radially capillary seal, as well as defining a small surface area from which evaporation can occur.