Air bearing surface design for inducing roll-bias during...

Details Air bearing surface design for inducing roll-bias during... Air bearing surface design for inducing roll-bias during...

2001-01-16

2003-06-03

Tupper, Robert S. (Department: 2652)

Dynamic magnetic information storage or retrieval

Fluid bearing head support

Disk record

C360S235600, C360S235700, C360S235800, C360S236300

Reexamination Certificate

active

06574074

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates in general to an improved disk drive, and in particular to an improved air bearing design for a transducer in a disk drive.
2. Description of the Related Art
Generally, a data access and storage system consists of one or more storage devices that store data on magnetic or optical storage media. For example, a magnetic storage device is known as a direct access storage device (DASD) or a hard disk drive (HDD) and includes one or more disks and a disk controller to manage local operations concerning the disks. Disks are rigid platters that are usually made of aluminum alloy or a mixture of glass and ceramic, and are covered with a magnetic coating. Typically, two or three disks are stacked vertically on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm).
The only other moving part within a typical HDD is the head stack assembly. Within most HDDs, one magnetic read/write head or slider is associated with each side of each platter and flies just above the platter's surface. Each read/write head is mounted on a suspension to form a head gimbal assembly (HGA). The HGA is then attached to a semi-rigid arm apparatus that supports the entire head flying unit. Several semi-rigid arms may be combined to form a single armature unit.
Each read/write head scans the surface of a disk during a “read” or “write” operation. The head and arm assembly is moved utilizing an actuator that is often a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which the spindle is also mounted. The base casting is in turn mounted to a frame via a compliant suspension. When current is fed to the motor, the VCM develops force or torque that is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head approaches a desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop directly over the desired track.
To successfully achieve file performance, the read/write head must fly steadily at a given fly height over the disk with minimal variations. Since the variations in fly height are dependent on the various sensitivities of the fly height to the process parameters as well as the variability of the parameters, a state-of-the-art air bearing surface (ABS) design technology and tight process control are mandatory to minimize such variations. Common dominant process parameters affecting fly height include head-gimbal assembly moments, crown and etch depths.
In the prior art, the disk and carbon overcoat on the slider are subject to extensive wear during start/stop cycles. Recent designs have employed load/unload technology to reduce this problem, where a ramp is provided for each slider/suspension assembly at the inner or outer diameter of the disk where the slider is parked. However, during the loading/unloading sequence, the sliders may still contact the disks. In order to read or write data in the load/unload zone (near the outer radial edges of the disks), the inner diameter corners/edges of the slider must not contact the disk surface. Even for systems that do not write data in the load/unload zone, it is desirable to avoid the inner diameter edges of the slider contacting the disk surface since the slider will need to fly over this zone. Thus, further improvements for disk drive components are needed to enhance performance and reduce the potential for data erasure.
SUMMARY OF THE INVENTION
One embodiment of a recording head for a disk drive with a load/unload mechanism has an air bearing on one surface. The air bearing suitably comprises a patterned set of three air bearing pads, and at least one etch surface. The three air bearing pads are spaced apart from each other, with two of the air bearing pads located on the leading edge, and the other pad on the trailing edge. The air bearing also has an offset pad at one of the trailing corners of the air bearing surface. This configuration gives the air bearing superior performance characteristics over prior art designs with load/unload mechanisms, particularly in regard to contact with the disk during loading and unloading sequences.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the preferred embodiment of the present invention, taken in conjunction with the appended claims and the accompanying drawings.


REFERENCES:
patent: 5796551 (1998-08-01), Samuelson
patent: 5973880 (1999-10-01), Hashimoto et al.
patent: 6128162 (2000-10-01), Kameyama
patent: 6351345 (2002-02-01), Kameyama

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