# US 7,609,484 B2 · Magnetic disk device

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- Number: US 7,609,484 B2
- Document ID: US7609484B2
- Status: Granted
- Kind: B2
- Application number: 11/255,977
- Filed: 2005-10-24
- Published: 2007-02-01
- Granted: 2009-10-27
- Earliest claimed: 2005-07-28
- Assignees: Fujitsu Limited
- Inventors: Hiroyuki Iwahara
- Web page: https://patentgrep.com/patent/US7609484B2

## CPC

- G11B 5/4833: {Structure of the arm assembly, e.g. load beams, flexures, parts of the arm adapted for controlling vertical force on the head (G11B5/484 takes precedence)}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

In a magnetic disk device, a magnetic circuit drives an actuator carrying a magnetic head, so that the magnetic head is moved to a target track on a surface of a magnetic disk. A base has a threaded-hole part to which the magnetic circuit is fastened with a screw. A blocking member is provided to enclose a gap which is formed between the magnetic circuit and the threaded-hole part when the magnetic circuit is fastened to the threaded-hole part.

## Claims

### Claim 1

A magnetic disk device comprising:
a magnetic circuit including a lower yoke and an upper yoke, the upper yoke having a washer part formed in an outer area of the upper yoke and driving an actuator carrying a magnetic head, so that the magnetic head is moved to a target track on a surface of a magnetic disk;
a base mounting a spindle motor which rotates the magnetic disk and having a threaded-hole part opposing the washer part;
a screw being inserted to the washer part and the threaded-hole part and fastening the upper yoke to the base; and
a blocking member arranged between the washer part and the threaded-hole part, the blocking member enclosing a gap outside the lower yoke between a bottom surface of the washer part and a top surface of the threaded-hole part,
wherein the threaded-hole part is internally arranged in a column formation projection from a bottom plate of the base, and an inside surface of the blocking member is fitted in contact with an outside surface of the column formation of the base.

### Claim 2 (depends on 1)

The magnetic disk device according to claim 1 wherein the blocking member is a tubular member which is made of an elastic material.

### Claim 3 (depends on 2)

The magnetic disk device according to claim 2 wherein the tubular member comprises a fixed portion fixed onto the threaded-hole part, and a projecting portion upwardly projecting from the threaded-hole part and contacting the magnetic circuit with an elastic deformation.

### Claim 4 (depends on 2)

The magnetic disk device according to claim 2 wherein the tubular member is made of an elastic material which is either a rubber or a resin.

### Claim 5 (depends on 1)

The magnetic disk device according to claim 1 wherein a reference-height projection is formed on the base, and the magnetic circuit is placed on the reference-height projection so that positioning of the magnetic circuit in a height direction on the bottom plate of the base is performed.

### Claim 6 (depends on 1)

The magnetic disk device according to claim 1 wherein the blocking member is a packing member which is made of an elastic material.

### Claim 7 (depends on 1)

The magnetic disk device according to claim 1 wherein an inner diameter of the blocking member is smaller than an outer diameter of the column formation.