A hard disk drive unit constituted in the following manner can prevent
leaks of gas caused by a deformed gasket assembly, can enhance operational
performances of the hard disk drive unit in accordance with using purposes
and can be assembled more easily. A monolithically constituted gasket
assembly with a cover for fitting to a case of the hard disk drive unit
comprises: a cover plate constituting the cover made of aluminum, plastics
and the like having piercing holes at predetermined positions; a gasket
fitted to the cover plate via the piercing holes; and a ring constituting
the cover arranged around an outer periphery of the gasket. A gap formed
between the cover plate and the ring, and a gap formed between the cover
plate and the case for the hard disk drive unit are sealed by the gasket.
