Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record
Reexamination Certificate
2000-06-26
2002-04-16
Ometz, David L. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Disk record
Reexamination Certificate
active
06373654
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a disk device and an apparatus for writing a reference signal into the disk device or, in particular, to a housing structure of a disk device and an apparatus for writing a reference signal into the disk device, in which the unnecessary base vibration is reduced by improving the base rigidity to thereby realize a very close track pitch in the disk device.
2. Description of the Related Art
In recent years, disk devices such as magnetic disk devices and optical disk devices have found applications as an external storage units of computers. Signals are transmitted and received at ever-increasing speeds between the head and the control circuit of these disk devices and the storage capacity of the disk devices is increased every year. Once the disk size is fixed, the storage capacity is improved by increasing the TPI (tracks per inch) and hence reducing the pitch of the tracks on the disk.
With the increased density of the tracks due to an increased TPI, a slight vibration may displace the head from an intended track to deteriorate the reliability of the disk device. A disk device having a disk built therein having high-density tracks, therefore, is desirably improved in base rigidity to reduce vibration.
A conventional magnetic disk device which is a kind of a disk device generally comprises a bath-tub type of base housing therein at least a disk, a spindle motor for rotating the disk, a carriage with a head at the forward end thereof and an actuator having a voice coil motor. This base is enclosed by a cover through a gasket. In this magnetic disk device, the signal reproduced by the head is withdrawn out of the actuator by a flexible circuit board mounted on the side of the carriage and led to and demodulated by a circuit on a fixed board protruded from the bottom of the base.
The magnetic disk device requires work called a servo track write operation for writing the servo information as a reference signal into the disk at the time of manufacture thereof. This servo track write operation is performed with all the parts built into the magnetic disk device. At the time of servo track write operation, first, a reference head is inserted into the base from outside of the magnetic disk device, and a reference signal is written on the outermost peripheral portion of the disk on which nothing has been written. The outermost peripheral portion of the disk in which the reference signal is written is where nothing can be read from by the built-in head. Then, the reference signal thus written is reproduced by the reference head thereby to confirm the disk position, and the internal head is driven by an external source in accordance with the detected position thereby to write the servo information in the disk.
Generally, the disk in which the reference signal is written is located close to the base bottom. For this reason, a reference head insertion hole from which to insert the reference head is formed in the side of the base. Upon completion of the servo track write operation, the reference head is withdrawn out of the reference head insertion hole, which is then hermetically enclosed by attaching a seal over it.
In the conventional disk device, the base is vibrated by the rotation of the spindle motor at the time of servo track write operation, thereby deteriorating the quality of the servo signal written under that condition. There has not been available any means capable of writing the reference signal while suppressing the vibration of the disk device.
Further, in the case where the actuator of the conventional magnetic disk device is placed on a predetermined track while the device is in use, the vibration generated by the rotation of the spindle motor is transmitted to the base through the mounting end thereof thereby causes vibration of the base, or the base is vibrated due to the fact that the base bottom is flat, with the result that it becomes difficult for the actuator to remain stationary. In the worst case, the data cannot be read.
Furthermore, consider the conventional seek operation in which the actuator moves to a predetermined track of the disk while the disk device is in operation. The base is easily affected by the reaction force of the seek operation, so that the base is vibrated, thereby increasing the time required for moving to the predetermined track.
A higher density of track pitch is essential for the future realization of a high-capacity disk device. Nevertheless, the above-mentioned vibration problem makes it difficult to increase the density of the track pitch.
SUMMARY OF THE INVENTION
In view of this, a first object of the invention is to provide a housing structure of a disk device comprising a spindle motor with at least a recording disk mounted thereon, a carriage with at least a head mounted thereon for exchanging signals with the disk, an actuator for driving the carriage and a base of a bath-tub type having built therein the spindle motor, the carriage and the actuator, wherein the vibration of the base is reduced by improving the base rigidity, thereby making it possible to increase the density of track pitch.
A second object of the invention is to provide a housing structure having a reference head insertion hole for a disk device comprising a spindle motor with at least a recording disk mounted thereon, a carriage with at least a head mounted thereon for exchanging signals with the disk, an actuator for driving the carriage and a base of a bath-tub type having built therein the spindle motor, the carriage and the actuator, the disk device having such a configuration as to improve the rigidity of the base, wherein a reference signal can be written accurately in the disk at the time of manufacture of the disk device and the disk device is not adversely affected by the reference head insertion hole after writing the reference signal.
A third object of the invention is to provide an apparatus for writing a reference signal into a disk device having a housing structure for achieving the above-mentioned first and second objects.
In order to achieve the above-mentioned first object, according to the present invention, there is provided a housing structure of a disk device comprising a spindle motor with at least a recording disk mounted thereon, a carriage with at least a head mounted thereon for writing information into or reading information from the disk, an actuator for driving the carriage and a base of a bath-tub type having built therein the spindle motor, the carriage and the actuator, wherein the spindle motor, the carriage and the actuator are hermetically sealed by a cover mounted on the upper surface of the base, and the base includes a reference head insertion hole into which a reference head is inserted for writing the reference signal into the disk at the time of manufacture of the disk device, the housing structure further comprising at least a damping means mounted on the bottom of the base of a bath-tub type or on the base side adjacent to the bottom for reducing the vibration of the base.
In the first form of the damping means, the thickness of the base bottom plate is increased to a maximum within a specified base size. In the case where the disk device is of a 3.5-in. type, for example, the thickness of the base bottom plate can be increased to 5 mm or more.
According to the first form of the damping means, the increased thickness of the base bottom plate increases the base rigidity and thereby reduces the base vibration.
In a second form of the damping means, the hole for mounting the spindle motor formed in the base is reduced in size, a protrusion is formed on the base for accommodating the flange of the spindle motor, and a mounting hole of the required minimum size is formed at the forward end surface of the protrusion. In the case where the disk device is of 3.5 inch type, for example, the size of the mounting hole can be defined as 13.5 mm or less.
According to the second form of the damping means, the size of the mounting hole for the spindle
Arai Terushige
Aruga Keiji
Asao Yasuyoshi
Ino Tsuneyori
Iwahara Hiroyuki
Fujitsu Limited
Greer Burns & Crain Ltd.
Ometz David L.
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