Hitachi, Ltd.

Jun Naruse

Tsuyoshi Takahashi

Hiroshi Nishida

Kazuo Nakagoshi

Jyousei Shimizu

Kenji Mori

Masami Suzuki

Takuji Ogawa

Yuji Nishimura

Yoshiyuki Hirano

Katsumi Kawamura

Hiroshi Fukui

Yuzo Kadomukai

Yutaka Sugita

Masaaki Matsumoto

Shinji Narishige

Yozo Nakamura

Hajime Aoi

Masanobu Hanazono

Yokuo Saitoh

Hiromu Hirai

Hirotsugu Fukuoka

Tomio Suzuki

Shunichi Mitsuya

Toshio Akatsu

Masayuki Katsumoto

Kazuto Kinoshita

Haruaki Otsuki

Naoki Maeda

Fujio Yamamoto

Susumu Ebihara

Mikio Higashi

Muneo Kawamoto

Takeo Hayakawa

Kunihiro Motoyoshi

The spacing between a magnetic disk surface and a magnetic head tends to greatly decrease with an increasing request for higher density records. Measuring and controlling the small spacing is important for stabilized recording or reading. A substrate is attached to a side of a support which supports the magnetic head. Light is irradiated onto a surface of the substrate and totally reflected thereby. The small spacing is measured by measuring the quantity of the totally reflected light. An actuator is controlled such that the measured small spacing is maintained at a target value to thereby realize constant small-spacing control.

Method and apparatus for controlling a small spacing between a magnetic

In a magnetic disk apparatus, a head positioning signal is written on a magnetic disk, the written positioning signal is read out, the read positioning signal is demodulated to produce a position signal, and a data write/read head is positioned to a predetermined track in responses to the produced position signal. A head positioning signal is written into write tracks adjacent to each other along a radial direction of the magnetic head, the positioning signal is read out by tracing a read track bridging the write tracks, and a positioning error of the head positioning signal is generated from a shift of the read positioning signal with respect to the read track. Furthermore, the position signal is over-written by actuating the write head in the radial direction according to the positioning error.

Method and apparatus for writing magnetic head positioning signal

A magnetic disk apparatus includes a magnetic disk, a magnetic head which performs information recording and reproducing for the magnetic disk, a load spring for supporting the magnetic head, a head arm for fixing the load spring, a housing for housing these components, a shaft which fixes the head arm, bearings for supporting the shaft rotatably on the housing, and a motor which is coupled to the shaft. The motor comprises a motor cover, a permanent magnet which is divided into a plurality of segments and fixed on the shaft, and a coil which is fixed on the interior surface of the motor cover by being spaced with a certain gap from the permanent magnet. The shaft is included with a counter weight so as to complement the weight of the head arm, load spring and magnetic head. The coil has linear conductor sections parallel to the shaft, with the total number of linear sections being set equal to the total number of segments of permanent magnet.

Magnetic disk apparatus using a rotary actuator for magnetic head

A magnetic head disk apparatus has a housing with one thicknesswise end providing the front side and the other thicknesswise end providing the rear side of the apparatus. The apparatus further has a plurality of head disk assemblies each including at least one combination of a magnetic head and a magnetic disk. The head disk assemblies are arranged in a plurality of rows not only in heightwise and breadthwise directions but also in the thicknesswise direction of the housing. With this arrangement, it is possible to accommodate a multiplicity of head disk assemblies with a high space factor in the housing.

Magnetic disk apparatus having improved arrangement of head disk

A magnetic disk system utilizes both of voice coil motor and a piezoelectric element provided on a head supporting arm to precisely position a head to a predetermined position on a disk. The piezoelectric element is built in the distal end portion of the head supporting arm and is restricted in respect of its movement by a resilient mechanism which has low rigidity in the driving direction of the piezoelectric element and high rigidity in the other directions. The resilient mechanism is formed by pairs of doubled parallel leaf springs so arranged that each pair is disposed on either side of the piezoelectric element.

Disk system with sub-actuators for fine head displacement

An electronic apparatus, such as a disk apparatus, has a plurality of electronic units such as magnetic head-disk units and at least one power source unit for supplying power to the electronic units. The arrangement of the electronic apparatus is such that, on a frame of the apparatus, the plurality of electronic units are vertically arranged in such a manner as to form a first arrangement system, while the at least one power source unit is arranged in such a manner as to form a second arrangement system above the first arrangement system. The apparatus has an air flow passage for causing cooling air to flow from a lower portion of the electronic apparatus to the inside thereof, pass through the first arrangement system, thereby pass through the second arrangement system, and then be discharged to the outside of the apparatus. This arrangement enables cooling air to flow in a simplified manner, which in turn enhances the cooling efficiency, and also enables electrically connecting cables to be arranged in a simple wiring system.

Disk apparatus having an improved cooling structure

This invention provides a magnetic disk device having a total memory capacity of 30 giga bytes or more, or more desirably 30.about.40 giga bytes. The magnetic disk used in this magnetic disk device has a plane record density of 45.about.80 mega bits per square inch. The thin film magnetic head has a pole thickness (P.sub.T), a magnetic flux density (B.sub.s), a magnetic gap depth (G.sub.d) and a record wavelenth (.lambda.) which satisfy the formula

Magnetic disk device and method of recording/retrieving information

A magnetic disk apparatus capable of reducing the vibration thereof is disclosed, in which a linear access mechanism for driving a magnetic head is provided with anti-reaction force generating means for generating an anti-reaction force capable of offsetting a reaction force generated in driving a carriage mounted with the magnetic head.

Linear access mechanism with driving force reaction cancelling device

An axial force exerting in the axial direction of a rotary actuator is uniformly applied to a plurality of axially arranged ball bearings of a bearing set to hold inner and outer rings of each ball bearing in optimum position, thereby heightening the rigidity of the bearing set. A waved washer is interposed between the ball bearings and distributes the axial force so as to axially slide the ball bearings. While being slidden to the optimum positions, the ball bearings are bonded for fixing.

Rotary actuator and bearing support therefor

Rotary actuator and fabrication process therefor

A linear actuator assembly for linearly the reciprocatingly moving magnetic heads in a magnetic disk storage apparatus. This linear actuator has a carriage for supporting magnetic heads, and a voice coil for moving the carriage. The sectional configurations of the carriage and the voice coil are equalized, thereby enabling the transmission of the driving force from the voice coil to the carriage without any eccentricity. This linear actuator also has a vibration absorbing mechanism for absorbing vibrations caused when the linear actuator operates, and a runaway prevention mechanism for limiting the movable range of the carriage.

Linear actuator assembly for accessing a magnetic memory disc

A disc memory device has a disc memory assembly comprised of a disc, head and a head actuator. The assembly is movably mounted to a base of the disc memory device such that it can move in the same direction as an operative direction of the head actuator, thereby ensuring that vibrations generated in response to acceleration/deceleration of the actuator can be absorbed by the whole of the disc memory assembly.

Vibration absorbing support assembly for a disc memory

A spindle assembly for magnetic disks of both-end support type has a hub for fixing the disks, a shaft to which the hub is fixed, a pair of bearings which are spaced in vertical or horizontal direction, a pre-loading spring for pre-loading one of the bearings, and a housing composed of housing parts which accommodates the hub, shaft, bearings and the pre-loading spring. The spindle assembly further has an axial reference surface formed on the hub at a right angle with respect to the shaft, and another axial reference surface formed on one of the housing parts at a right angle with respect to the vertical portion of the bearing associated with the one of the housing parts. When the shaft is mounted in the one of the housing parts with the hub and the pre-loading spring fitted therearound, the hub is axially urged by the spring such that the axial reference surface thereon is brought into abutment with the axial reference surface on the one of the housing parts. As a result, the axis of the spindle assembly is determined by the abutment between the reference surfaces and by the bearing in the one of the housing parts. The bearing in the other of the housing parts is axially aligned with the thus determined axis of the spindle assembly.

Spindle assembly for magnetic disks

A magnetic head loading apparatus serves to load a magnetic head on the surface of a disc-shaped magnetic recording medium rotating continuously so as to perform the recording and reproduction of data. The magnetic head is shifted from unload to load position by means of a drive means. In order to prevent damage to the recording medium due to the collision of the magnetic head with the recording medium, the drive means is so controlled as to cause the magnetic head to decellerate as the magnetic head approaches the load position.

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Odawara, Japan

Jun Naruse