JPH05342840

PURPOSE:To keep tight closure without blocking up a respiration passage and to promote assembling properties by taking the open air in from the respiration passage of a diaphragm structure, absorbing its moisture with a silica gel, passing it through a respiration filter and supplying it into a shroud and also securing the respiration passage with a groove of a cap. CONSTITUTION:A respiration chamber is arranged at a hole of a lower end of a base 12, and is composed of the respiration filter 13, the cap 16 having a diaphragm respiration passage, the silica gel 14 covered with a cover and a silica gel room cover 15. The cap 16 is formed in a two-stepped cylindrical shape, where the groove in a cruciate shape is engraved on its upper surface, having a diaphragm respiration ventilating through hole 22 in the center. A step part 23 of the cap 16 is inserted into a hole of the room cover 15 to introduce the air into the cover 15 from the ventilating hole 22. The ventilating hole of the cap 16 is made to be of a diaphragm structure to reduce the intrusion of the air containing moisture, and intruded moisture is absorbed by the silica gel 14, and then the air at low humidity is passed through the respiration filter 13 to remove dust and is taken into a magnetic disk chamber. The open air is secured in communication by the groove 21 even in case the silica gel 14 is scattered.