JPH097321A - Magnetic disk device and coil - Google Patents

Abstract

PURPOSE: To make a resonant point of a mechanism system of a driving part be of a high frequency, thereby improving the positioning precision of a magnetic head and an access time thereof, by improving the rigidity of a coil part of a coil movable type actuator. CONSTITUTION: A metal member 6 which has a ring-shaped part along the direction of a winding and wherein a notch is provided in a part of the ring- shaped part is fitted to the inside of a coil 5 of a driving part 4 of a coil movable type actuator. Thereby realizing an improvement in the rigidity of a coil part of the coil movable type actuator inexpensively without causing deterioration of other performances and a resonant point of a mechanism system can be made to be of a high frequency. Thereby improving the positioning precision of a head and an access time thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device, and more particularly to a structure of a rotatable coil drive type actuator for moving and positioning a head on a magnetic disk by a voice coil motor.

[0002]

2. Description of the Related Art A magnetic disk drive is a high-performance personal computer or workstation and a large-scale computer.
With the downsizing of computers, there is an increasing demand for large capacity, downsizing, and high-speed access.

In the magnetic disk drive which is required to have these performances, the position control information recorded on the magnetic disk is read back and controlled by the magnetic head mounted on the actuator. These actuaries
A voice coil motor is mainly used to drive the motor.
There are two types of the method, a linear type and a swing type. In particular, the oscillating actuator driven by rotation is very excellent in terms of reducing inertial momentum, and is very useful for improving access time and reducing power consumption with a fox space. It is valid. In order to reduce inertial momentum, these actuators usually have a magnetic circuit on the side of the fixed part and are structured to be driven by a coil.

As an example of this kind, the structure of a rotatable coil drive type actuator of a magnetic disk device is as described in Japanese Patent Laid-Open No. 6-251511.

[0005]

In the above prior art, when the actuator is driven, force is applied to the coil from the magnetic circuit by the Fleming's left-hand rule, but the coil has a structure in which a wire made of aluminum or copper is wound. Therefore, the mechanical system resonance frequency is reduced due to insufficient rigidity in the magnetic head position control direction.

As described above, in the magnetic disk device, the position control information recorded on the magnetic disk is read out by the magnetic head mounted on the actuator, and the feedback control is performed. A decrease in system resonance frequency causes an increase in position control error of the magnetic head and deterioration of access time.

An object of the present invention is to solve these problems easily and inexpensively.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention aims to improve the rigidity of the coil portion of a rotatable coil drive type actuator in which movement and position are controlled by a voice coil motor. , To prevent the mechanical system resonance in the actuator drive unit from decreasing.

As a means for specifically implementing the present invention, a metal member having an annular shape along the winding direction inside the coil and having a notch provided in a part of the annular portion is attached. Alternatively, the metal member of the actuator drive unit may have a structure in which the coil periphery is surrounded in an annular shape along the winding direction and a part of the annular part is cut out. These structures can be realized more easily and cheaply than using a metal member or a part of the actuator driving part.

[0010]

According to the present invention, the force is applied to the coil from the magnetic circuit by the Fleming's left-hand rule when the actuator is driven, but the rigidity in the magnetic head position control direction is improved and the mechanical system resonance frequency is prevented from lowering. . Also, by having an annular type along the winding direction, it is possible to suppress the increase of inertia moment as much as possible to improve rigidity and reduce the generation of eddy current loss, and the notch shape provided in a part of the annular part This prevents the short-circuit effect due to the back electromotive force generated in the annular portion.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1, FIG. 2 and FIG. 3 are views showing the internal structure of a magnetic disk device according to an embodiment of the present invention. The magnetic disk 1 for describing the position control information and data is fixed to a spindle motor-2 which is a means for rotationally driving the magnetic disk, and the position control information and data can be read and written. A head assembly 3 including a magnetic head to be performed, a circuit portion 9 for transmitting a signal, a coil 5, and a metal member 6 having an annular shape along the coil winding direction and having a notch 11 in a part of the annular portion. An actuator drive unit 4 rotatable by a rotating shaft 12 is contained in a housing 10 together with a magnetic circuit unit 8 of a voice coil motor. The magnetic circuit section 8 of the voice coil motor has magnets 7a and 7b. FIG.
FIG. 4 is a sectional view showing the relationship between the magnetic circuit portion 8 of the voice coil motor and the coil 5. In this figure, the magnets 7a and 7b have their magnetic polarities (N pole and S pole) reversed, and
The magnetic circuit is formed by the flow of the magnetic flux indicated by the arrow, to which the magnet 15 is attached. The arrow 12 shown in FIG. 2 shows an example of the direction of the current flowing through the coil 5. As a result, as can be seen from FIG. 4, a force is transmitted to the actuator drive unit 4 through the coil 5, and the rotary shaft 12 Centered on arrow 14
Move in the direction of. At this time, in the actuator drive section that does not have the metal member 6 as shown in FIG. 5, the mechanical system resonance frequency is lowered because the rigidity of the coil section 5 that transmits the force is low. This phenomenon is also shown in the resonance mode by the eigenvalue analysis by the finite element method as shown in FIG. 6, and in FIG. 7 the mechanical system transfer characteristics (head position acceleration / coil input) in the actuator state of FIG. FIG. 8 shows the actual measurement value of the electric current) and the actual measurement value of the transmission characteristic of the mechanism system of the actuator drive unit according to the present invention shown in FIG. It is apparent that the mechanical system resonance frequency is improved ((300 Hz) according to the present invention.

Further, due to the arrangement of the metal member 6 and the magnets 7a and 7b shown in FIGS. 1 and 2, when the actuator 4 moves as shown by an arrow 14, the metal member 6 has a notch 11. If not present, a counter electromotive current similar to that generated in the coil will also be generated in the metal member 6, but the movement of the actuator drive unit 4 will be hindered because it is short-circuited.

FIG. 9 is a diagram showing an actuator drive portion of another embodiment of the present invention. In this embodiment, an actuator drive unit 4'made of metal surrounds the coil in an annular shape along the winding direction, and has a structure in which a notch 16 is provided in a part of the annular portion. Has the same effect as the embodiment shown in FIG.

[0015]

According to the present invention, the rigidity in the magnetic head position control direction is improved, the mechanical system resonance frequency in the actuator drive section can be increased, and the magnetic head positioning accuracy and access time can be improved. Enable improvement.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal configuration of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an actuator which is an embodiment of the present invention.

FIG. 3 is a diagram showing an actuator drive unit according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the relationship between the coil and the magnetic circuit of the voice coil motor.

FIG. 5 is a diagram showing a conventional actuator drive unit.

FIG. 6 Resonance mode diagram by eigenvalue analysis by finite element method

FIG. 7: Mechanical system transmission characteristic of a conventional actuator drive unit

FIG. 8 is a mechanical system transmission characteristic of an actuator drive unit according to the present invention.

FIG. 9 is a diagram showing an actuator drive unit according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Magnetic disk 2 ... Spindle motor 3 ... Head assembly 4 ... Actuator
Motor drive unit 5 ... coil 6 ... metal member 7a, b ... magnet 8 ... voice coil motor magnetic circuit unit 9 ... signal transmission circuit 10 ... housing 11 ... metal member notch 12 ... rotary shaft 13 ... current Flow direction arrow 14 ... Actuator moving direction 15 ... Magnetic circuit section yoke 16 ... Metal cue actuator cutout section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Ishibashi 2880, Kozu, Odawara-shi, Kanagawa Stock Company Hitachi Storage Systems Division

Claims (7)

[Claims] 1. A magnet having a magnetic disk, a driving means for rotating the magnetic disk, a magnetic head and a rotatable coil drive type actuator for positioning the magnetic head on the previous magnetic disk by a voice coil motor. In the disk device, a magnetic disk having an annular shape along the winding direction inside the coil of the actuator drive part, and a metal member having a notch provided in a part of the annular part is attached. apparatus. 2. A magnetic disk device according to claim 1, wherein the metal member is fixed by a polymer adhesive. 3. The magnetic disk device according to claim 1, wherein the metal member is integrated with the coil by using a polymer material. 4. A magnetic disk, a drive means for rotating the magnetic disk, a magnetic head and a rotatable coil movable actuator for controlling the movement and position of the magnetic head on the magnetic disk by a voice coil motor. In a coil used in a magnetic disk device having a magnetic disk device, a magnetic member having an annular shape along the winding direction inside the coil, and a metal member having a notch provided in a part of the annular portion is attached. Coil for. 5. A coil for a magnetic disk device according to claim 4, wherein the metal member is fixed by a polymer adhesive. 6. A coil for a magnetic disk device according to claim 4, wherein the metal member is integrated with the coil by using a polymer material. 7. A magnetic disk and a driving means for rotating the magnetic disk, a magnetic head and a rotatable coil movable actuator for moving and controlling the position of the magnetic head on the magnetic disk by a voice coil motor. A magnetic disk device having a structure in which a metal member of the actuator drive part surrounds the coil in an annular shape along the winding direction and a part of the annular part is cut off. .