Dynamic magnetic information storage or retrieval – Head – Head accessory
Reexamination Certificate
2002-01-31
2004-08-24
Watko, Julie Anne (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Head accessory
C360S265100
Reexamination Certificate
active
06781791
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to disk drives, and in particular to a disk drive including a disk plate for modifying airflow adjacent a disk.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes the disk drive base, a cover, at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA) that includes a transducer head supported by a slider (collectively referred to as “head” or “slider”) for reading and writing data to and from the disk.
The spindle motor includes a spindle motor hub that is rotatably attached to the disk drive base. The spindle motor hub has an outer hub flange that supports a lowermost one of the disks. Additional disks may be stacked and separated with annular disk spacers that are disposed about the spindle motor hub. The spindle motor typically includes a spindle motor base that is attached to the disk drive base. A shaft is coupled to the spindle motor base and the spindle motor hub surrounds the shaft. The spindle motor hub may be rotatably coupled to the shaft and therefore the spindle motor base typically via a pair of bearing sets. A stator is positioned about the shaft and is attached to the spindle motor base. A magnet element is attached to the hub flange. The stator includes windings that selectively conduct current to create a magnetic field that interacts with the various poles of the magnet element. Such interaction results in forces applied to the spindle motor hub that tend to rotate the spindle motor hub and the attached disks.
The head stack assembly has an actuator assembly having at least one head or slider, typically several, for reading and writing data to and from the disk. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to the generated servo control signals from the disk controller. In so doing, the attached sliders are moved relative to tracks disposed upon the disk.
The head stack assembly includes the actuator assembly and a flex circuit cable assembly attached to the actuator assembly. A conventional “rotary” actuator assembly (also referred to as “rotary actuator” or simply “actuator”) typically comprises an actuator body, a pivot bearing cartridge, a coil portion that extends from one side of the actuator body to interact with one or more permanent magnets to form a voice coil motor, and one or more actuator arms which extend from an opposite side of the actuator body to a distal end of the actuator assembly. The actuator body includes a bore and the pivot bearing cartridge engaged within the bore for allowing the actuator body to rotate between limited positions. At least one head gimbal assembly (HGA) is distally attached to each of the actuator arms. Each head gimbal assembly biases a head towards the disk. In this regard, the actuator assembly is controllably rotated so as to move the heads relative to the disks for reading and writing operations with respect to the tracks contained on the disks.
A head gimbal assembly includes a suspension assembly, an electrical interconnection, and a head. The suspension assembly (also simply referred to as “suspension”) typically includes a base or swage plate, a load beam and a gimbal. The load beam is typically a thin elongate plate spring. One end of the load beam is affixed to a distal end of the actuator arm via a thin hinge plate and the base plate. This may be accomplished through a swage operation. The other end of the load beam supports the gimbal. The gimbal may be integrally formed with the hinge plate that extends from its attachment to the actuator arm and along the length of the load beam. The gimbal in turn supports the slider and is formed to flex in a hinge like manner in relation to the disk. In this regard, the load beam acts to suspend the slider from the actuator arm and therefore the load beam. The load beam transmits a biasing force known as a gram load to the slider to “load” it toward the disk. Because of the aerodynamic characteristics of the slider, rotation of the disks induces airflow that causes the slider to be lifted away from the disk in opposition of the gram load. The slider is said to be “flying” when in this state. A flexure in the form of a thin laminate may be overlaid upon the load beam. The gimbal may be integrally formed with the flexure. The flexure may include an interiorly open frame from which the gimbal is cantilevered to support the slider. The electrical interconnection may take the form of electrical leads that are embedded in the flexure for communicating data signals to and from the head embedded in the slider. In this regard, the electrical interconnection is connected with the flex cable assembly for communication with the printed circuit board assembly.
A topic of concern is the desire to reduce the effects of airflow generated within the disk drive due to rotation of the disks. Of particular concern is the occurrence of turbulent airflow that may tend to excite a resonance response of the actuator assembly. This results in an increase in the percent off-track values of the associated head. Further, such disk rotation induced airflow may result in a force applied to the actuator assembly, i.e., windage. In addition, such disk rotation induced airflow may result in vibration of the disk or disk flutter. Accordingly, there is a need in the art for an improved disk drive for mitigation of such disk rotation induced airflow in comparison to the prior art.
SUMMARY OF THE INVENTION
An aspect of the invention can be regarded as a disk drive that includes a disk drive base and a spindle motor hub rotatably coupled to the disk drive base. The disk drive further includes a disk disposed about the spindle motor hub. The disk drive further includes a rotary actuator rotatably coupled to the disk drive base. The rotary actuator includes a distal end and is formed to pivot for translating the distal end adjacent the disk to a parked position. The disk drive further includes a disk plate. The disk plate includes a plate body coupled to the disk drive base. The plate body is disposed substantially about and parallel with the disk for modifying air flow adjacent the disk during operation of the disk drive. The disk plate further includes a head limiter portion extending from the plate body. The head limiter portion is vertically aligned with the distal end with the distal end in the parked position.
According to various embodiments of the foregoing disk drive, the distal end may be disposed between the head limiter portion and disk with the distal end in the parked position. According to another embodiment, the head limiter portion is disposed between the distal end and disk with the distal end in the parked position. The head limiter portion may be engaged in sliding contact with the distal end with the distal end in the parked position. The distal end includes a suspension assembly, and the head limiter portion may be sized and configured to engage the suspension assembly in sliding contact with the distal end in the parked position. The disk plate may be formed of a metal material, and may include a nonconductive coating. The disk plate may be formed of a molded plastic material. The head limiter portion may be integrally formed with the plate body.
The disk plate may further include an inner disk limiter portion extending from the plate body towards the disk. The disk may include an inner annular non-data region, and the inner disk limiter portion may be vertically aligned with the inner annular non-data region. The inner disk limiter portion may be formed of a metal material, and the inner disk limiter portion may include a nonconductive coating. The inner disk limiter portion may
Griffin Gary C.
Gustafson John R.
C. Kim, Esq. Won Tae
Shara, Esq. Milad G.
Stetina Brunda Garred & Brucker
Watko Julie Anne
Western Digital Technologies Inc.
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