JPH11238328A - Magnetic disk drive having magnetic circuit driving means - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a magnetic disk device capable of suppressing a rotational vibration of a magnetic disk device which is generated by a seek operation and adversely affecting the positioning of a head, and which enables high-speed access. . A magnetic circuit is rotatably supported on a base, a rotation axis of the magnetic circuit is positioned at a position passing through a center of gravity of the magnetic circuit, and magnetic circuit driving means for moving the magnetic circuit is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a magnetic disk drive.

[0002]

2. Description of the Related Art A magnetic disk drive is designed to increase the recording density to increase the storage capacity and to increase the head access speed to increase the data transfer rate.

The head access operation of the magnetic disk drive includes a seek operation for moving the head at high speed near the target position and a settling operation for positioning the head at the target position. In the seek operation, the voice coil motor of the head actuator serves as a driving force. Then, the magnetic disk device vibrates due to the reaction force of the driving force. This vibration is a rigid vibration caused by installing the magnetic disk device on a frame or the like inside the personal computer.

[0004] In other words, the frame or the like becomes a spring,
This is a vibration in which the magnetic disk device becomes a mass. The movement of the magnetic disk device when vibrating is mainly rotational movement.
As the device rotates, no moment is transmitted to the rotatably supported head actuator, so that the head is moved relative to the device. This causes a problem that the head positioning deteriorates and the time for the settling operation becomes longer.

[0005] As a conventional technique for realizing high recording density,
There is one disclosed in JP-A-59-210573.
This is a structure in which a magnetic circuit called a magnet assembly is rotatably supported coaxially with a rotation axis of a carriage including an arm or the like. According to this structure, the moment due to the reaction force of the head driving force is offset, the device vibration is reduced, and the head positioning accuracy is improved.

As a prior art similar to this, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent No. 128753. This is a structure in which the magnetic circuit is rotatably supported coaxially with the rotation axis of the carriage, and has a structure similar to that of JP-A-59-210573. The difference is that two sets of magnetic circuits and voice coils are provided. The effect is the same as in JP-A-59-210573. However, Japanese Patent Application Laid-Open No. 5-128753 discloses a structure for driving a magnetic circuit.

[0007]

However, the known technique disclosed in Japanese Patent Application Laid-Open No. Sho 59-210573 cannot completely cancel the moment. The moment of the above-described known technique will be described with reference to FIGS.

As described above, the carriage and the magnetic circuit are rotatably supported on the rotating shaft P. As shown in FIG. 9, when moving the head in the direction of the arrow, the coil 16
Generates a driving force of Fo. At this time, the reaction force acting on the rotation axis P is Fc, and Fc is transmitted to the base.

The reaction force acting on the magnetic circuit is Fcr,
The power is transmitted to the base via the rotation axis P. Fo, Fc and Fcr are the same size. However, the force Fp and Fcr transmitted to the base via a magnetic circuit shown in FIG. 10, Fp = Fcr relational expression {1- (m * Lg * Lc ) / (I + m * Lg 2)} is satisfied . Where m is the mass of the magnetic circuit, I
Is the moment of inertia of the magnetic circuit.

Lg and Lc are as shown in FIG.
In the known art, Fp and Fcr cancel each other on the rotation axis P. However, actually, a force of the difference between Fp and Fcr remains, and this force becomes a moment for rotating the magnetic disk device, so that the moment cannot be completely canceled.

In the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open No. HEI 5-128753, when no structure for driving the magnetic circuit is provided, most of the reaction force can be suppressed by the viscoelastic member. Cannot be offset. Further, in this structure, it is necessary to reduce the size of the magnetic circuit 2 in order to mount the device to the standard dimensions of the device, and there is a problem that the driving force of the VCM is reduced.

An object of the present invention is to provide a magnetic disk drive capable of canceling a reaction force generated by a seek operation without suppressing a VCM driving force, suppressing a rotational movement of the magnetic disk drive, and consequently providing high-speed access. Is to do.

[0013]

According to the present invention, a magnetic circuit is rotatably supported on a base, and the rotation axis of the magnetic circuit is set at a position passing through the center of gravity of the magnetic circuit. The provision of the magnetic circuit driving means for moving the circuit makes it possible to provide a magnetic disk drive capable of high-speed access.

That is, in the present invention configured as described above,
It is possible to provide a magnetic disk device in which the rotational movement of the magnetic disk device is suppressed, and thus high-speed access is possible.

[0015]

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

A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, a magnetic circuit which is a component of a motor for moving a head is rotatably supported on a base, and a rotation axis of the magnetic circuit is set at a position passing through a center of gravity of the magnetic circuit. The circuit driving means is provided.

FIG. 1 is a plan view of the magnetic disk drive according to this embodiment, FIG. 2 is a sectional view of the magnetic circuit shown in FIG. 1, and FIG. 3 is a perspective view. 4 to 7 show how the reaction force of the seek operation is transmitted.

The configuration of the magnetic disk drive will be described with reference to FIG. The housing of the magnetic disk drive includes a base 1 and a cover 9 (not shown). A spindle motor 3 that rotates at a predetermined speed is fixed to the base 1. A magnetic disk 6 as a recording medium is fixed to the spindle motor 3. Further, the shaft 2 of the bearing body 2 is attached to the base 1 in the lateral direction of the magnetic disk 6 fixed to the spindle motor 3 so that the axis is parallel to the spindle motor 3.
a is fixed. An arm 8 holding a slider (not shown) on which the magnetic head is mounted is fixed to the carriage 7.

Power for moving the magnetic head is generated by a voice coil motor. A coil (not shown), which is a component of the voice coil motor, is fixed to the carriage 7. Magnetic circuit 4 as another component
Is connected to the base 1 via the bearing 13 as shown in FIG.
And the cover 9.

The position of the rotation axis of the magnetic circuit 4 is arranged so as to pass through the center of gravity of the magnetic circuit 4. In the plan view of FIG. 1, the center of gravity of the magnetic circuit 4 coincides with the rotation axis. The lid 14 in FIG. 2 is a member for shutting off the inside and the outside of the apparatus, and is attached to the base 1. Preload member 15
Is for applying a preload to the bearing 13 and is attached to the cover 9.

As shown in FIG. 3, the magnetic circuit 4 includes an upper yoke 4a, a lower yoke 4b, a side yoke 4c, and a magnet 4d. One of the side yokes 4c is provided with a plane portion indicated by an arrow. is there. This flat portion is a surface on which one end of the piezoelectric element 12 is fixed. The other end of the piezoelectric element 12 is fixed to the base 1.

The magnetic circuit 4 can be minutely driven by slightly expanding and contracting the piezoelectric element 12 itself. The method of expanding and contracting the piezoelectric element 12 is to apply a predetermined bias voltage to the piezoelectric element 12 and change the voltage according to the amount of expansion and contraction. The direction of expansion and contraction of the piezoelectric element 12 is set to point to the center of gravity of the magnetic disk drive.

The voice coil motor controls the direction and magnitude of the moment acting on the carriage 7 by appropriately controlling the direction and time of energization of the coil 16 fixed to the carriage 7, thereby controlling the magnetic head. The magnetic disk 6 is positioned at a desired position.

An FPC (Fle) mounted in a curved shape
xible Printed Circuit) 5 has one end on the carriage 7,
The other end is fixed to the base 1 via the FPC fixing member 10. The FPC 5 includes a signal line of the magnetic head and a coil 1.
6 power lines are wired, and through the connector 11,
It is connected to a control circuit board (not shown).

The control circuit board is fixed to the base 1 together with spacers and the like. The spindle motor 3, magnetic disk 6, bearing 2, slider, arm 8, carriage 7, voice coil motor, FPC 5, FPC fixing member 10, connector 11, piezoelectric element 12, bearing 1
The components 3 and the like are housed in a closed space formed by the base 1, the cover 9, the screws, and the like.

4 to 7 show how the reaction force of the seek operation is transmitted. In these figures, only the lower yoke 4b of the magnetic circuit 4 is shown in these figures for easy understanding.
FIG. 4 shows the driving force Fco and the reaction forces Fc and Fcr when seeking in the direction of the arrow. Fc is a force transmitted from the carriage 7 to the base 1 via the bearing body 2, and
It is the same direction and the same size as. Fcr is a reaction force received by the magnetic circuit 4 and has the same magnitude in the opposite direction to Fo.

In a normal magnetic disk drive, since the magnetic circuit 4 is firmly fixed to the base 1, Fcr is transmitted to the base 1 via the magnetic circuit 4. At this time, the two reaction forces Fc and Fcr have the same magnitude and are opposite to each other, and the couple (= Fcr * L0) is applied to the base 1, which is a housing.
Act as

As a result, the magnetic disk device rotates and vibrates. This vibration is a rigid vibration caused by installing the magnetic disk device on an internal frame of a personal computer or the like.
In other words, the vibration is such that the frame becomes a spring and the magnetic disk device becomes a mass. The movement of the magnetic disk drive when vibrating due to the action of a couple is mainly a rotational movement that adversely affects the positioning of the head. However, in this embodiment, since the magnetic circuit 4 is rotatably supported at the position of the center of gravity, and furthermore, the piezoelectric element 12 is provided, the reaction force transmitted to the base 1 is different from that of a normal magnetic disk device.

FIG. 5 shows the force acting on the base 1 due to Fcr in FIG. Fp is a force transmitted to the base 1 via the bearing 13, and has the same direction and the same magnitude as Fcr. That is, a couple having a magnitude of Fcr * (L0−L1) acts on the two reaction forces Fcr and Fp. Further, Fcr is a moment of rotating the magnetic circuit 4 of Fcr * L1.

This moment is received by the base 1 via the piezoelectric element 12. The size Fm is (L
1 / L2) * Fcr. However, in the present embodiment, as shown in FIG. 6, the direction of Fm (the direction of expansion and contraction of the piezoelectric element 12) is directed to the center of gravity of the magnetic disk device, and therefore, the moment for rotating the magnetic disk device is reduced. Not be. Therefore, the moment for rotating the device is Fcr * due to two reaction forces of Fcr and Fp.
There is only a couple having a magnitude of (L0-L1). By canceling out the couple, a moment for rotating the device can be eliminated.

In order to realize this, it is necessary to drive the magnetic circuit 4 by expanding and contracting the piezoelectric element 12. FIG. 7 shows a force generated when the magnetic circuit 4 is driven by energizing the piezoelectric element 12 and extending in the direction of the arrow.

The reaction force of the force Fd acting on the fixed position between the piezoelectric element 12 and the magnetic circuit 4 is applied to the base 1 via the piezoelectric element 12.
And Fdp acting on the base 1 via the bearing 13. These are couples of opposite directions and the same magnitude, and the magnitude is Fd * L2. Here, the energization of the piezoelectric element 12 is controlled in order to make Fd a predetermined size such that Fd * L2 = Fcr * (L0-L1).

As a control method, it is easy to make the energization waveform to the piezoelectric element 12 the same as the energization waveform to the coil 16, but it is not limited to this. Of course, the energization of the piezoelectric element 12 is synchronized with the energization of the coil 16. As a result, a moment for rotating the magnetic disk device can be eliminated.

A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the number of piezoelectric elements 12 is increased to two in the magnetic disk drive of the first embodiment. The two piezoelectric elements 12 are installed coaxially in the direction of expansion and contraction. When one is extended, the current is supplied to each piezoelectric element 12 so as to contract the other. According to this, the effect of eliminating the moment for rotating the magnetic disk device is the same as in the first embodiment. However, the fixing strength between the magnetic circuit 4 and the piezoelectric element 12 can be increased.

Next, a third embodiment of the present invention will be described. The present embodiment utilizes the characteristic of the piezoelectric element that an electromotive force is obtained when a load is applied in the magnetic disk drive of the second embodiment, and one of the piezoelectric elements 12 is used for power generation.
The other is expanded and contracted by the electric power. The structure is
This is the same as FIG. According to this, the effect of eliminating the moment for rotating the magnetic disk device is the same as in the first embodiment. However, it is not necessary to control the piezoelectric element 12 to be energized in synchronization with the coil 16.

FIGS. 9 and 10 show a fourth embodiment of the present invention.
This will be described below. This embodiment is different from the magnetic disk drive of the first embodiment in that the magnetic circuit 4 is supported by a bearing 13.
Instead, a plurality of leaf springs 17 are used.

FIG. 9 is a plan view of this embodiment. FIG.
The illustration of the upper yoke 4a and the coil 16 is omitted to make the leaf spring 17 easy to see. FIG. 10 shows a perspective view of the magnetic circuit 4 and the leaf spring 17. In order to support the rotation of the magnetic circuit 4 at the position of the center of gravity, the plurality of leaf springs 17 need to be installed toward the center of gravity of the magnetic circuit 4. According to this, the effect of eliminating the moment for rotating the magnetic disk device is the same as in the first embodiment. However, since the bearing 13 is not used, the thickness of the device can be reduced, so that the structure is suitable for a thin device.

A fifth embodiment of the present invention will be described with reference to FIGS.
2 will be described. This embodiment is different from the magnetic disk drive of the first embodiment in that the magnetic circuit 4 is supported by a bearing 1.
3, a guide 18 and a sliding member 19 are used.

FIG. 11 is a plan view of this embodiment. The guide 18 is installed on the base 1. The sliding member 19 is provided between the magnetic circuit 4 and the base 1, cover 9 and guide 18, but is not shown in FIG. In order to rotate and support the magnetic circuit 4 at the position of the center of gravity, the center of the arc of the guide 18 needs to coincide with the center of gravity of the magnetic circuit 4.

FIG. 12 is a sectional view of the magnetic circuit 4 and the guide 18. Base 1, cover 9, magnetic circuit 4, and guide 1
A sliding member 19 is fixed to 8. Due to the expansion and contraction of the piezoelectric element 12, the opposing sliding member 19 slips and the magnetic circuit 4
Is a moving structure. As the sliding member 19, a slippery material such as Teflon is used.

According to this, the effect of eliminating the moment for rotating the magnetic disk drive is the same as that of the first embodiment. However, since the bearing 13 is not used, the thickness of the device can be reduced, so that the structure is suitable for a thin device.

With the above configuration, the rotational movement of the magnetic disk drive can be suppressed, and a magnetic disk drive capable of high-speed access can be provided.

[0043]

According to the present invention, it is possible to eliminate the moment for rotating the magnetic disk drive, suppress the rotational vibration of the magnetic disk drive, and provide a magnetic disk drive capable of high-speed access.

[Brief description of the drawings]

FIG. 1 is a plan view of a magnetic disk drive according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a magnetic circuit of the magnetic disk device shown in FIG.

FIG. 3 is a perspective view of a magnetic circuit of the magnetic disk device shown in FIG. 1;

4 is an explanatory diagram showing a driving reaction force of the magnetic disk device shown in FIG.

FIG. 5 is an explanatory diagram showing a force applied to a base by a driving reaction force shown in FIG. 4;

FIG. 6 is an explanatory diagram showing a moment for rotating the magnetic disk device by the force shown in FIG. 5;

FIG. 7 is an explanatory diagram showing a moment for canceling the moment shown in FIG. 6;

FIG. 8 is a plan view of a magnetic disk drive according to a second embodiment of the present invention.

FIG. 9 is a plan view of a magnetic disk drive according to a fourth embodiment of the present invention.

10 is a perspective view of a magnetic circuit of the magnetic disk device shown in FIG.

FIG. 11 is a plan view of a magnetic disk drive according to a fifth embodiment of the present invention.

12 is a sectional view of a magnetic circuit of the magnetic disk device shown in FIG.

FIG. 13 is an explanatory diagram showing a driving reaction force of a magnetic disk device according to a conventional technique.

FIG. 14 is an explanatory diagram showing the driving reaction force and the force received by the base shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base, 2 ... Bearing body, 3 ... Spindle motor, 4
... magnetic circuit, 5 ... FPC, 6 ... magnetic disk, 7 ... carriage, 8 ... arm, 9 ... cover, 10 ... FPC fixing member, 11 ... connector, 12 ... piezoelectric element, 13 ... bearing, 14 ... lid, 15 ... Preload member, 16 ... coil, 17
... leaf spring, 18 ... guide, 19 ... sliding member.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiko Shimizu 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. Inside the Machinery Research Laboratory (72) Inventor Shozo Saegusa 2880 Kozu, Odawara-shi, Kanagawa Prefecture Storage Systems Division, Hitachi, Ltd. (72) Inventor Masahiko Sega 2880 Kozu, Kozuhara, Odawara-shi, Kanagawa Storage Systems Division, Hitachi, Ltd.

Claims (1)

[Claims] A magnetic disk as a recording medium; a head for performing recording and reproducing operations on the magnetic disk; a motor for generating a driving force for moving the head;
A movable member and a fixed member that are components of the motor,
A carriage on which the head and the movable member are mounted,
In a magnetic disk drive including a bearing body rotatably supporting the carriage and a base to which the bearing body is fixed, the fixing member is rotatably supported by the base, and a rotation axis of the fixing member is A magnetic member having a fixed member driving means for rotating the fixed member at a position passing through a center of gravity of the fixed member, wherein a driving direction of the fixed member driving means is directed to a center of gravity of the magnetic disk device; Disk device.