Seagate Technology Incorporated

Ryan T Ratliff

Nigel Frank Misso

Roy Lynn Wood

Lealon Ray McKenzie

Kenneth Lee Pottebaum

Curtis A Trammell

Steve Scott Eckerd

Otis L Funches

Mohammad Noman Ahmad

A disc drive includes a base and a voice coil magnet attached to the base. The voice coil magnet has a first portion for providing a magnetic field having a first direction and magnitude, and a second portion for providing a magnetic field having a second direction and magnitude. The voice coil magnet also has a transition zone between the first portion and the second portion of the voice coil magnet where the magnetic field from the first portion substantially cancels the magnetic field from the second portion of the voice coil magnet. The disc drive also includes an actuator assembly rotatably attached to base. The actuator assembly includes a yoke, and a voice coil attached to the yoke of the actuator. The voice coil is positioned within the magnetic field of the voice coil magnet such that passing a current through the voice coil generates a second magnetic field to position the actuator assembly. A ferromagnetic material is attached to the actuator assembly. The ferromagnetic material is positioned within the magnetic field of the voice coil magnet to induce a force from the magnetic field of the voice coil magnet to drive the actuator to a park position.

Passive actuator for assisting commutational ramp loading

An inductive rotational accelerometer for assisting in servo control of a hard disc drive using a torsional mass-spring system in combination with an inductance sensitive circuit to detect and measure the rotational vibrations imposed on a hard disc drive. The inductive rotational accelerometer includes a frame member coupled to the disc drive, the frame member supporting a pin on which is disposed a rotational mass. The rotational mass supports conductive blocks which with the rotational mass and the frame member provide a path for inductance.

Rotational inductive accelerometer

An apparatus and associated method for providing a strain relief in support of a medial portion of a terminal end of an electrical wire that is used in the construction of an actuator coil for a disc drive assembly. The strain relief apparatus has a base that is attached to the actuator assembly, an upstanding post around which the electrical wire is wrapped to provide a frictional engagement between the wire and the post, and a flange depending from a distal portion of the post to urge the wire onto the post and retain the wire about the post during routing of a distal portion of the terminal end that is associated with manufacturing steps of electrically connecting the actuator coil to the disc drive control system. In a preferred embodiment the strain relief has a pair of posts so that each terminal end is wrapped individually about one of the posts. In an alternative preferred embodiment the strain relief has a single post about which both terminal ends are wrapped.

Strain relief for an actuator coil

A bobbin for providing a heat sink for an actuator coil of a voice coil motor, the actuator coil having a plurality of windings arranged about a central aperture, the bobbin having a body member supported within the central aperture of the actuator coil. The body member has a plurality of fins which increase the surface area within the actuator coil to provide enhanced heat dissipation. The bobbin is formed from a thermally conductive, dielectric material to facilitate the dissipation of heat generated in response to the application of current to the actuator coil to reduce the operational temperature thereof while preventing detrimental eddy currents, thereby allowing an increased current flow to effectuate a decrease in seek time.

Heat sink for a voice coil motor

A damper for dampening resonance created by a voice coil motor of a disc drive and transmitted to a supporting enclosure, the resonance capable of creating noise signals to the disc drive servo control system. The damper has a dampening member and a liner, the liner being a magnetically permeable member that is magnetically attracted to the voice coil motor and thereby pressingly engaging a magnet housing of the voice coil motor. In a preferred embodiment the dampening member is an acrylic polymer. In an alternative embodiment the dampening member is a fluoroelastomer. The magnet housing has characteristic features that increase the magnetic flux to the liner.

Disc drive magnet housing electro mechanical resonance dampening system

Apparatus and method for increasing sweep angle of a rotary actuator in a disc drive. The actuator supports a head adjacent a surface of a disc and an actuator coil adjacent a permanent magnet assembly. The actuator coil has first and second active lengths which magnetically interact with adjacent first and second magnet portions of the permanent magnet assembly, with the permanent magnet assembly generating a magnetic flux reversal at a transition zone between the first and second magnet portions. The head is moved by applying current in a first direction to move the actuator coil in a selected coil direction, thereby causing a selected one of the first and second active lengths to cross the transition zone. The polarity of the current is then reversed so that the current is applied in a second direction opposite the first direction, which causes the actuator coil to continue to move in the selected coil direction.

Extending actuator range through magnetic flux reversal detection

An apparatus and method for detecting rotational vibration applied to a disc drive having a rotary actuator adjacent a rotatable disc. The actuator supports a head adjacent a recording surface of the disc and an actuator coil in a magnetic field of a magnetic circuit of a voice coil motor. A second, velocity sense coil is further coupled to the actuator and immersed in the magnetic field of the magnetic circuit, with the velocity sense coil being electrically isolated from the actuator coil. Rotational vibration is detected in relation to a sense voltage induced across the velocity sense coil as the magnetic circuit is moved relative to the velocity sense coil. A data transfer operation between the head and a host device is interrupted when the magnitude of the rotational vibration exceeds a specified magnitude. A servo circuit applies current to the actuator coil to position the head relative to the disc recording surface in relation to servo information transduced by the head, as well as in relation to the sensed voltage from the velocity sense coil.

Rotational vibration detection using a velocity sense coil

An actuator latch for latching an actuator of a disc drive having a rotating disc that induces airflow when the disc drive is operational, the actuator latch having a shaft supported by a baseplate, the shaft supporting a plurality of vanes to rotate the shaft in response to airflow generated by disc rotation. A locking member is operably engaged with the shaft and moveable thereby to a latched position and to an unlatched position, the actuator being secured by the locking member in the latched position and the actuator being released to move freely in the unlatched position. The locking member is caused to be positioned in the unlatched position when airflow rotates the vanes and shaft, and a biasing member reverse rotates the shaft when the airflow ceases, thus returning the locking member to the latched position when the disc drive becomes non-operational.

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Oklahoma City, OK, United States of America

Ryan T Ratliff