HARD DISC DRIVE

摘要

An HDD in which the frictional resistance does not increase even if the rotational speed of the storage medium increases and stable operation even against humidity variation and temperature variation is possible. HDD constituent elements (4,5) are accommodated in a closed case (3) that is isolated from the outside atmosphere. The atmosphere inside the case (3) is kept at low humidity, that is the water vapor pressure is about 0.1 atmospheric pressure or less, preferably about 0.005 atmospheric pressure or less. When the atmospheric pressure is 1. Alternatively, the air is replaced a gas such as a nitrogen gas that contains no humidity and exhibits low frictional resistance. Further alternatively the pressure of the air inside the case (3) is reduced to about 0.9 to 0.5 atmospheric pressure, preferably 0.7 atmospheric pressure, to lower the air resistance. Under this reduced pressure, a case (3) made of a thick or high-rigidity material is used. The case has an element which can be anything capable of following or dinary variations of the atmospheric pressure and temperature, for example, an element comprising an expandable member (10) such as bellows and deformable with a variation of the atmospheric pressure.