Abstract: A rotary valve comprises a stator member with a stator face, the stator member having at least two stator channels for conducting a fluid and opening into the stator face; a rotor member with a rotor face facing and in contact with the stator face, the rotor member having a rotor channel in the rotor face, wherein the rotor member is rotatable with respect to the stator member about a rotation axis, such that in a conducting position, the rotor channel interconnects the at least two stator channels to be in fluid communication; and a rotary encoder assembly adapted for determining a rotary position of the rotor member, the rotary encoder assembly comprising an encoder member and an encoder module, which is adapted to sense a rotary position of the encoder member. The encoder member is rigidly connected to the rotor member and surrounds the rotor member.

Abstract: A servo track writer for a head disk assembly and a method of making the head disk assembly using the servo track writer are disclosed. The head disk assembly includes an enclosure having an opening and a base and an actuator arm coupled to the base and having a servo writer positioning arm facing surface. The servo track writer includes a platform for supporting the head disk assembly. The platform includes a base portion, a column extending substantially perpendicular to the base portion, and an elongated servo writer positioning arm for protruding through the opening and supported by the column. The positioning arm includes a main body, a tip having an actuator arm facing surface for abutting the positioning arm facing surface, and a vibration damper positioned between the main body and the tip. The vibration damper damps vibrations induced in the actuator arm by dissipating energy transferred between the platform and the actuator arm.

Abstract: A head disk assembly (HDA) for a hard disk drive includes vibration damping structure. The HDA also includes an enclosure, a disk, a pivot bearing cartridge, and a head stack assembly (HSA). The enclosure includes a base that preferably includes integral side walls. The disk has a recording surface that has an annular landing zone. The pivot bearing cartridge includes a shaft fixed to the enclosure, and the head stack assembly is connected to the pivot bearing cartridge for rotation relative to the shaft. The HSA includes a head supported to be moved radially relative to the recording surface and to be brought to rest at a position in the landing zone. The base has a plurality of interior-facing surfaces including a major interior-facing surface parallel to the recording surface. Significantly, one of the interior-facing surfaces of the base serves as a bearing surface against which the vibration damping structure is compressed.