Magnetic fluid seal containment shield

A magnetic seal for a disk drive data storage unit is described where the magnet assembly comprising an annular magnet and two annular pole pieces are adhesively attached with the magnet intermediate the pole pieces and the assembly thereof then forcibly inserted, creating a force fit, into a shield which is formed as an annulus with an interior cylindrical surface engaging the exterior cylindrical surfaces of the magnet assembly. The force fit insures electrical continuity between the shield and the pole pieces. The shield extends into close proximity with the shaft being sealed and is provided with a relieved region immediately adjacent the interior cylindrical surface of the pole pieces to form a reservoir for receiving, trapping and retaining any ferromagnetic fluid which may escape from the gap between the pole pieces and the shaft. A mating shield is then assembled onto the previously assembled components after the introduction of the ferromagnetic fluid into the seal gaps. All elements of the seal assembly are adhesively sealed to adjacent elements to prevent the formation of gaps or capillaries which may act to attract and transport ferromagnetic fluid away from the seal gap between the pole pieces and the shaft. At least one of the shields is in reliable electrical contact with the hub into which the entire assembly is inserted.