Abstract: In a disk drive device having a double cover structure with low-density gas enclosed therein, embodiments of the present invention help to securely perform leak inspection on an outer cover and to prevent defects caused in joining the outer cover. According to one embodiment, a hard disk drive (HDD) comprises a flow amount adjuster on a base-facing side of its inner cover. Helium gas in an enclosure goes out through a ventilation hole via diffusion channel of a flow amount adjuster. The emitted helium gas remains in the space between the inner cover and an outer cover. This achieves easier detection of the leakage of helium gas from the joining section of the outer cover and prevention of emission of too much helium gas from the enclosure.

Abstract: Embodiments of the invention reduce disk fluttering while ensuring good assemblability in a magnetic disk apparatus. A magnetic disk apparatus comprises a recording disk that is an information medium configured by one or plural disks; a motor causing the recording disk to rotate; a carriage supporting a head that records information to, or plays back information from, the recording disk; a casing housing the recording disk; and a shroud disposed surrounding an outer periphery of the recording disk. A groove that extends along the recording disk is formed, vertically asymmetrical with respect to an outer peripheral surface of the recording disk, in the shroud surface at a position where a corner portion formed by the outer peripheral surface and a top surface or bottom surface of the recording disk extends in a radial direction.

Abstract: In a disk drive device having a double cover structure with low-density gas enclosed therein, embodiments of the present invention allow a more reliable leak inspection to be performed on the second cover and to prevent defects caused by joining the secondary cover. An HDD according to an embodiment of the present invention comprises a ventilation path from a ventilation hole on an inner cover to a space between the inner cover and an outer cover. An outer peripheral end of an adhesive layer is apart from a joining section, which is exposed in the space. Helium gas flowing out of the ventilation hole flows to the space via the ventilation path and remains within the space. This enables detection of leakage of the helium gas from the joining section to be performed more easily.

Abstract: Embodiments of the present invention help to prevent leakage of low-density gas during low-density gas injection into a disk drive device and to perform low-density gas injection efficiently. In a hard disk drive (HDD) according to one embodiment of the present invention, an injection hole filter with a valve function is attached to a helium injection hole in order to inject helium gas in an enclosure. The injection hole filter has a valve member configured to operate in an open state or closed state. The open state is a state while the helium gas is being injected and the closed state is a state after the helium gas has been finished to be injected. The valve member is in the open state if the outside pressure is higher than the inside pressure and is in the closed state if the inside pressure is higher than the outside pressure.

Abstract: Embodiments of the invention reduce disk fluttering while ensuring good assemblability in a magnetic disk apparatus. In one embodiment, a magnetic disk apparatus comprises a recording disk that is an information medium configured by one or plural disks; a motor causing the recording disk to rotate; a carriage supporting a head that records information to, or plays back information from, the recording disk; a casing housing the recording disk; and a shroud disposed surrounding an outer periphery of the recording disk. A groove that extends along the recording disk is formed, vertically asymmetrical with respect to an outer peripheral surface of the recording disk, in the shroud surface at a position where a corner portion formed by the outer peripheral surface and a top surface or bottom surface of the recording disk extends in a radial direction.