JP2002093086A - Magnetic disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk drive in simple structure with high reliability by eliminating a part where a microactuator slides and decreasing the number of microactuators when an actuator using a piezoelectric element is actualized. SOLUTION: A carriage-side actuator fixation part and a magnetic-head-side actuator fixation part of a microactuator mount part are connected by a flexible connection part and a microactuator, and those are arranged at mount parts which are halved along the lengthwise center line of a suspension. Consequently, there is no part which comes into slide contact with the microactuator, so dust due to a slide is not produced and high reliability is obtained by the simple structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly, to a magnetic head support mechanism equipped with a microactuator for precisely positioning a magnetic head on a target track, and a magnetic disk drive using the same.

[0002]

2. Description of the Related Art With the recent increase in the capacity of magnetic disk drives, magnetic heads must be positioned with extremely high precision with respect to target tracks. for that reason,
In a magnetic disk drive, there has been proposed a drive mechanism having a structure in which a voice coil motor provided on a side opposite to a magnetic head with respect to a rotation center of a carriage coarsely moves and a suspension portion is provided with an actuator for fine movement.

For example, Japanese Patent Application Laid-Open No. H11-16311 discloses a configuration in which a microactuator is provided between a suspension having a load beam and a magnetic head in addition to a coarse actuator and driven.

[0004]

As the microactuator, an electromagnetic type using a coil and a magnet has been conventionally studied, but recently, from the viewpoint of rigidity and manufacturing cost, PZT has been studied.
A piezoelectric type using a piezoelectric element such as described above is being put to practical use.

However, since the piezoelectric element is a brittle material, it is susceptible to impact and sliding, and has a drawback that dust is likely to be generated from a sliding part or a part where stress is concentrated at the time of impact or driving of the piezoelectric element. . In magnetic disk devices, the distance (flying height) between the flying surface of the slider on which the magnetic head is mounted and the disk surface is very small, several tens of nanometers, from the viewpoint of improving the recording density. It is difficult to maintain the flying height and recording / reproduction becomes impossible. In the worst case, the slider and the disk may be damaged, leading to a decrease in the reliability of the magnetic disk device.
Therefore, when using a piezoelectric element, the sliding part must be eliminated as much as possible, and the stress generated when an external shock is applied or when the piezoelectric element is driven must be minimized. There is.

Another problem is that it is necessary to reduce the number of piezoelectric elements used in order to secure the above-mentioned reliability and mass productivity.

Further, in a magnetic disk drive which employs a load / unload mechanism for retracting the magnetic head to the outside of the disk when the operation of the magnetic disk drive is stopped, the disk and the suspension are deformed by an external impact so that they come into contact with each other. In order to avoid damaging the disk surface, it is necessary to completely retract the suspension outside the disk. For this reason, there is also a problem that it is desired to reduce the width of the microactuator.

An object of the present invention is to solve (at least one of) the above-mentioned problems, and to reduce the number of piezoelectric elements,
An object of the present invention is to provide an actuator configuration which has a simple configuration, has a small number of sliding portions, and can perform accurate positioning, and a magnetic disk device using the same.

[0009]

In order to achieve the above object, a window is provided in a microactuator mounting portion, and an outer frame portion that does not intersect the suspension longitudinal center line of the window can be extended and contracted in the suspension longitudinal direction. A flexible connecting member is provided, and the outer frame portion is arranged outside the microactuator with respect to the suspension longitudinal center line. Thus, the microactuator does not come into contact with other members at the time of operation and at the time of impact except at the fixed portion, so that generation of dust due to sliding can be avoided. Also,
At the time of impact, the connecting member shares the stress generated at the time of impact,
During operation, the connection member is freely deformed, so that the concentration of stress on the microactuator can be reduced, and the reliability of the magnetic disk device can be improved.

In order to reduce the number of piezoelectric elements to be used, a flexible connecting member which can be extended and contracted is provided on one of the mounting tables of the piezoelectric element divided into two by the longitudinal center line of the suspension, and a microactuator is provided on the other. Thus, the generation of dust due to the above-described sliding can be avoided, and the number of actuators can be reduced.

Further, by making the shape of the expandable and contractible flexible connecting member convex in a direction away from the center of the disk, contact between the microactuator mounting portion and the disk can be avoided.

[0012]

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

FIG. 1 is a perspective view of a magnetic disk drive to which the present invention is applied, FIG. 2 is a perspective view of its suspension,
3 is a side view of the suspension, FIG. 4 is a top view of the suspension, FIG. 5 is an explanatory diagram of the operation of the microactuator, and FIG. 6 is a sectional view taken along line AA of FIG.

In this embodiment, a slider 3 having a magnetic head mounted on the tip of a load beam 1 via a flexure 2 is provided.
Is attached. The load beam 1 is fixed to one end of the microactuator mounting section 4 by welding or the like.
At the other end of the microactuator mounting section 4 is a mount 5
Are integrally formed. The mount 5 may be fixed separately by welding or the like. The sections from the load beam 1 to the mount 5 are referred to as a suspension herein. The mount 5 is fixed to the carriage 6 by swaging or the like.
The carriage 6 is driven by the driving force of the voice coil motor.
By rotating around the pivot shaft 7, the magnetic head can access any radial position on the disk 8. Further, a microactuator 9 composed of a piezoelectric element (piezo element) is fixed to the microactuator mounting section 4. By driving the microactuator 9, fine positioning of the magnetic head is performed.

The steps in FIGS. 2 and 6 are fixing places 45 for fixing the microactuator 9 to enable the microactuator to be easily fixed and to prevent the microactuator from protruding significantly upward. ing. The stepped portion is formed into a concave shape by pressing, etching, or the like so that the microactuator can be easily positioned. The microactuator mounting section 4 of this embodiment is integrally formed by an arm section 41, a magnetic head side microactuator fixing section 42, and a carriage side microactuator fixing section 43.

The arm portion 41 is disposed on the mounting portion 4 on the disk center side of the mounting portion 4 divided by the longitudinal center line 10 so as not to contact / slide with the microactuator 9. It is arranged on the actuator mounting section 4. By arranging the microactuator 9 and the arm portion 41 separately with the center line 10 as a boundary, they do not contact and slide. In other words, in the case of a structure in which the microactuator and the arm are overlapped in the height direction, contact / sliding that may occur can be prevented. Further, one end of the arm portion 41 is joined to the magnetic head side microactuator fixing portion 42, and the other end is joined to the carriage side microactuator fixing portion 43. The arm portion 41 has a convex shape in a direction away from the center of the disk so as to be flexible enough not to hinder the operation of the microactuator 9. The microactuator mounting section 4 is designed to prevent excessive deformation at the time of impact and to reduce the height of the entire suspension.
A thickness of about 15 mm to 0.3 mm is desirable.

The microactuator mounting section 4 is preferably formed by punching with a press or etching to reduce manufacturing tolerances and manufacturing costs.

The arm 41 must be flexible in the rotational direction and rigid in the plane direction, so as not to hinder the operation of the microactuator 9. To that end, it is effective to increase the path length of the arm (length along the center line of the shape) and to reduce the width of the arm. However, as the total width of the suspension (the distance from the suspension longitudinal center line to the farthest point of the arm) increases, the moment of inertia with respect to the suspension longitudinal center axis increases. And the magnetic head positioning operation is adversely affected. Therefore, it is desirable that the arm portion has a long path length while reducing the overall width of the suspension. In response to such a demand, the U-shape as shown in the present embodiment makes it possible to reduce the inertia moment about the longitudinal center axis of the suspension without increasing the moment of inertia as compared with, for example, a V-shaped arm shape. The length of the microactuator 9 can be increased.
Contact and sliding can be avoided.

In this embodiment, a U-shape is used, but a U-shape may be used. However, a U-shaped shape is desirable because stress concentration is small. Further, by making the arm portion 41 convex toward the suspension longitudinal centerline 10, the moment of inertia around the suspension longitudinal centerline 10 can be reduced. Thereby, torsional vibration can be suppressed. Also, in a magnetic disk device that employs a load / unload mechanism for retracting the magnetic head out of the disk when the disk is stopped, the disk may partially contact the suspension due to an impact, and the disk surface may be damaged. To prevent this damage, the suspension must be completely retracted out of the disk. In the present embodiment, the entire width of the suspension can be reduced by making the arm portion 41 convex toward the center line 10. Therefore, the distance (angle) at which the suspension is completely retracted from the disk surface
May be small. That is, it is easy to evacuate as a result.

As for the width of the arm portion 41, the thickness of the microactuator mounting portion is about 0.15 to 0.3 mm. The thickness is preferably equal to or greater than the thickness, and a width of about 0.3 to 0.4 mm is desirable.

FIG. 5 shows an example of a deformed state of the suspension when the microactuator is driven. Arrows in the microactuator 9 indicate directions of expansion and contraction of the microactuator 9. The microactuator 9 is provided with an upper electrode (not shown) and a lower electrode (not shown), and is fixed to the microactuator mounting section 4 by a conductive adhesive (not shown).
The microactuator mounting section 4 is electrically at 0 potential via the mount 5 and the carriage 6.

As shown in FIG. 5, when a signal is input to the upper electrode, the microactuator 9 expands and contracts by the signal electrode (positive and negative). The direction of expansion and contraction can be determined by the combination of the direction of polarization and the signal electrode. The magnitude of expansion and contraction is controlled by the magnitude of the voltage of the signal. For example, as shown in FIG. 5A, when the microactuator 9 is deformed to contract in the longitudinal direction, the entire suspension is deformed downward with respect to the center line as shown in FIG. Thereby, the slider 3 (not shown) can also slightly move below the center line. FIG.
When the microactuator 9 is deformed to extend in the longitudinal direction as shown in (2), the entire suspension is deformed upward with respect to the center line as shown in FIG. 5 (2).
As a result, the slider 3 (not shown) can be finely moved in the direction opposite to the direction shown in FIG.

In this case, as shown in FIG. 5, the arm 41 of the microactuator mounting portion 4 has such a shape that it can be easily deformed in both the longitudinal direction and the width direction of the suspension. Absent.

With these configurations, the microactuator 9 does not have a portion that contacts the microactuator mounting portion 4 except for the fixed portion. Further, even if the microactuator 9 is deformed during operation or when a shock is applied to the magnetic disk device, the microactuator 9 slides because there is no place to contact between the microactuator 9 and the microactuator mounting portion 4. There is no fear, and there is no possibility that the reliability of the magnetic disk device will be reduced due to the generation of dust. In addition, when an impact force is applied, the inertia force of the load beam 1 is applied to the microactuator 9, but the arm 41 of the microactuator mounting portion 4 shares the inertia force, so that the stress generated in the microactuator 9 is reduced. . Therefore, the microactuator 9 is less likely to be damaged, and the reliability of the magnetic disk device can be improved.

In the structure disclosed in Japanese Patent Application Laid-Open No. H11-16311, the slider-side microactuator fixing portion rotates around the intersection of the three support beams. For this reason, the microactuator must also be deformed following the fixed part. As a result, the microactuator is deformed other than required for driving the slider, and the stress generated in the microactuator is increased. Therefore, there is a problem that dust is more likely to be generated from the stress concentration portion. However, in the present invention, as shown in FIG. 5, since the arm portion 41 can be made flexible in both the longitudinal direction and the width direction of the suspension, the deformation of the microactuator 9 is not restrained, so that the risk of dust generation is reduced. As a result, the reliability of the magnetic disk device can be improved.

Next, in FIG. 7, the shape of the arm 41 is changed from a U-shape to a V-shape.
A second embodiment in the form of a letter is shown. Also, FIG.
A third embodiment in which the shape is a straight line is shown.

The only difference from the first embodiment is the shape of the arm 41. As the U-shape of the first embodiment is changed to the V-shape of the second embodiment and the straight type of the third embodiment, the center line distance of the arm portion 41 becomes shorter, and the rigidity in the longitudinal direction of the suspension increases. For this reason, when the displacement force of the microactuator is constant, the amount of minute displacement of the slider is reduced, so that a large amount of electric power is required to perform the same displacement as in the first embodiment. On the other hand, by improving rigidity,
The natural frequency of the suspension increases, and the suspension vibration caused by disturbance such as airflow caused by the rotation of the disk can be reduced. As a result, there is an advantage that the amplitude of vibration of the slider due to disturbance can be reduced. In addition, since the frequency of the eigenvalue increases, there is an advantage that control is easy.

In both the second embodiment and the third embodiment, as in the first embodiment, the microactuator 9 and the arm portion 41 are provided at different places, so that the two members slide and generate dust. There is no. Further, since the slider is minutely displaced by one microactuator, the reliability and the productivity (mass productivity) are excellent. Further, in the second embodiment, as in the first embodiment, the arm portion 41 has a V-shape and has a convex shape in the direction of the microactuator. Thereby, the rigidity of the arm portion 41 can be reduced, and
The overall width of the microactuator 9 can be reduced. In addition, since this has a convex shape in the direction away from the center of the disk, there is the same advantage as in the first embodiment, in that the microactuator mounting portion and the disk are unlikely to come into contact with each other due to an external impact.

When the displacement amounts in various arm shapes are obtained by calculation and are made dimensionless by the displacement of the first embodiment, the displacement of the first embodiment is about 0.8, and the displacement of the second embodiment is about 0.8. In the embodiment, only about 0.2 occurs. From this result, it can be seen that the U-shape of the first embodiment is the most flexible, and the displacement of the magnetic head is the largest when the piezoelectric element is driven. For this reason, the U-shape of the first embodiment is used when a large displacement of the slider is required, and the second shape is used when the eigenvalue (frequency) of the suspension is required to be higher than the displacement of the slider. What is necessary is just to select the shape of the arm part 41 of 3rd Example.

FIGS. 9 and 10 show a fourth embodiment of the present invention.
FIG. 13 is a top view showing a fifth embodiment. The difference between the first and second embodiments is that two arm portions 41 are provided on the microactuator mounting portion 4 for the purpose of improving the impact resistance. In the fourth embodiment, the arm 41 on the disk 8 side
It is convex in the direction away from the center of the disk. That is, it is directed to the suspension longitudinal centerline 10. For this reason, as shown in the figure, in a magnetic disk drive having a load / unload (L / UL) mechanism,
When the slider is retracted out of the disk, the arm 41 on the disk is completely retracted out of the disk 8, so that there is no contact between the two by an impact. This is the same as in the first embodiment.

Here, the L / UL mechanism of this embodiment is a mechanism in which the tab 11 provided at the tip of the suspension 1 rides on the ramp 20 and retracts, but the effect of this embodiment is limited to this mechanism. is not. The arm 41 farther from the disk includes a magnetic head side microactuator fixing part 42 and a carriage side microactuator fixing part 43.
In the direction away from the center of the disc (the arm on the disc side).
(Same direction as 41) and are connected in a U-shape that is convex. Thereby, the mounting position of the microactuator 9 is
As in the first embodiment, the arm 4 on the far side from the disk is kept outside the microactuator mounting section 4.
1 can be newly provided. By providing the microactuator 9 on the outside, a large displacement of the slider can be obtained with a small force.

The outer arm portion 41 can relieve the stress generated in the microactuator 9 when an external impact force is applied. Specifically, when a vertical impact is applied to the disk surface, the two arms 41
Accordingly, the inertia force of the suspension 1 at the time of impact is shared with the microactuator 9 and received, so that the stress generated in the microactuator 9 can be reduced as compared with the first embodiment. As a result, the shock resistance performance of the magnetic disk device can be improved, and the reliability can be increased. The effect of the arm portion 41 farther from the disk can be reduced by about 30% to 40% assuming that the maximum stress of the microactuator 9 in the absence thereof is 1. When the rigidity of the arm portion 41 is increased, the maximum stress of the microactuator 9 due to the impact can be reduced, so that the impact resistance can be improved.

On the other hand, providing two arms 41 and increasing the rigidity of the arms 41 can be achieved by the microactuator 9.
May hinder expansion and contraction. To avoid this,
In this embodiment, the shape of the arm portion 41 is U-shaped. Further, by making the arm 41 farther from the disk 8 convex in the direction away from the disk 8, there is no restriction on the size of the U-shape, and the arm 41 having low rigidity in the direction of expansion and contraction of the microactuator 9 can be used. Can be provided. As a result, the micro-actuator 9
Thereby, it is possible to obtain a sufficient slider displacement.

The difference between the fourth embodiment and the fifth embodiment is that in the fifth embodiment, the two arm portions 41 are formed in a U-shape protruding toward the suspension longitudinal center line 10.
By forming the arm 41 farther from the disk 8 into a U-shape protruding toward the center line 10 in the longitudinal direction of the suspension, the suspension mounting portion 4 around the center line 10 is formed.
Inertia force can be reduced. Thereby, the torsional vibration of the suspension 1 can be reduced. Also, in this embodiment, as in the fourth embodiment, the maximum stress of the microactuator 9 can be reduced by the arm portion 41, so that the impact resistance can be improved.

In FIG. 10, the arm 41 on the opposite side of the microactuator 9 with respect to the center line 10 may be connected in a straight line without forming a U-shape as described above.
In this case, the displacement amount generated by driving the actuator 9 becomes smaller when the same amount as the drive current of the configuration in FIG. 10 is applied. However, there is an advantage that the rigidity in the surface direction can be improved.

FIG. 11 shows a sixth embodiment. FIG.
The difference from this embodiment is that an arm 50 having substantially the same shape as the microactuator 9 is provided as a dummy actuator at a position facing the microactuator 9 across the center line 10. By providing the arm portion 50, it is possible to balance the left and right masses with respect to the center line 10. In this way, by adjusting the balance, the external force of the suspension (external force such as airflow generated due to the rotation of the disk)
Thereby, the torsional vibration generated in the torsional direction with respect to the center line can be suppressed. The torsional vibration degrades the positioning accuracy for moving the magnetic head in the disk radial direction. With the configuration of the present embodiment, there is a problem in the case of configuring with one microactuator.
Since the mass imbalance can be eliminated and the torsional vibration can be suppressed, the magnetic head can be positioned with high positioning accuracy.

Further, even when an external impact is applied by the dummy microactuator, the dummy actuator can share and receive a part of the impact, so that the impact force applied to the microactuator 41 can be reduced.
That is, the impact resistance performance can be improved. For example, when the magnetic disk drive is dropped, acceleration acts in a direction in which the suspension approaches or moves away from the disk surface. The microactuator is composed of a piezo element or the like, and the piezo element is a brittle material made of ceramics, so it is weak to an impact force, and there is a problem that the impact force causes cracks or the like and loses its function. For this reason, by providing the arm portion 50 as a dummy actuator, there is also an advantage that the impact force can be reduced as described above and the life of the device can be extended. It is needless to say that this configuration can be applied not only to the embodiment of FIG. 10 but also to other embodiments.

[0038]

According to the present invention, since the microactuator does not come into contact with other members during operation or impact except at the fixed portion, the generation of dust due to sliding can be avoided. In addition, at the time of impact, the connecting member shares the stress generated at the time of impact, and at the time of operation, the connecting member is freely deformed, so that the concentration of stress on the microactuator can be reduced. In addition, the number of microactuators used can be reduced. In addition, contact between the microactuator mounting portion and the disk due to external impact can be avoided. From these matters, the reliability of the magnetic disk device can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a magnetic disk drive on which a suspension according to a first embodiment of the present invention is mounted.

FIG. 2 is a perspective view of the suspension according to the first embodiment of the present invention.

FIG. 3 is a side view of the suspension according to the first embodiment of the present invention.

FIG. 4 is a top view of the suspension according to the first embodiment of the present invention.

FIG. 5 is a modified view of the first embodiment of the present invention when the microactuator is operating.

FIG. 6 is a sectional view taken along line AA of FIG. 2;

FIG. 7 is a perspective view of a suspension according to a second embodiment of the present invention.

FIG. 8 is a top view of a microactuator mounting portion according to a third embodiment of the present invention.

FIG. 9 is a top view of a suspension according to a fourth embodiment of the present invention.

FIG. 10 is a top view of a suspension according to a fifth embodiment of the present invention.

FIG. 11 is a top view of a suspension according to a sixth embodiment of the present invention.

[Explanation of symbols]

1 ... load beam, 2 ... flexure, 3 ... slider, 4
… Micro actuator mounting part, 5… Mount, 6…
Carriage, 7: pivot shaft, 8: disk, 9: microactuator, 41: arm.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiromitsu Masuda 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. F term in the system division (reference) 5D042 LA01 MA15 5D059 AA01 BA01 CA25 CA26 DA19 DA26 EA07 5D096 NN03 NN07

Claims (6)

[Claims] A slider mounted with a magnetic head for writing and reading information to and from a magnetic disk; a flexure for flexibly supporting the slider; and a load beam for applying an appropriate load to the slider. A microactuator mounting unit connected to the load beam,
In a head support mechanism having a microactuator provided on the microactuator mounting portion and a fixing portion for fixing the microactuator mounting portion to an arm of a carriage, an actuator fixing portion on the carriage side of the microactuator mounting portion may be magnetic. A head support, wherein a head-side actuator fixing portion is provided on one side with respect to the center line in the longitudinal direction of the load beam, and is connected to the other side of the center line by one flexible arm which can be extended and contracted. mechanism. 2. The head supporting mechanism according to claim 1, wherein said arm portion is formed in a convex shape toward said micro-actuator. 3. A flexure for flexibly supporting a slider equipped with a magnetic head for writing and reading information to and from a magnetic disk, a load beam for applying an appropriate load to the slider, and a In a head support mechanism having a connected microactuator mounting portion and a fixing portion for fixing the microactuator mounting portion to an arm of a carriage, the microactuator mounting portion has a width with respect to a load beam longitudinal center line. One side is divided into two in the direction
A head support mechanism comprising: a carriage-side actuator fixing portion; and a magnetic head-side actuator fixing portion, and a flexible arm portion capable of extending and contracting in a longitudinal direction is provided on the other side. 4. A slider having a magnetic head for writing and reading information to and from a magnetic disk, a flexure for flexibly supporting the slider, and a load beam for applying an appropriate load to the slider. A microactuator mounting unit connected to the load beam,
In a head support mechanism having a microactuator provided on the microactuator mounting portion and a fixing portion for fixing the microactuator mounting portion to an arm of a carriage, the microactuator mounting portion includes several arms and one arm.
The micro-actuator is provided on one side divided into two in the width direction with respect to the center line in the longitudinal direction of the load beam, and the arm portion has a shape convex in the micro-actuator direction. Head support mechanism. 5. A disk for recording information, a magnetic head for writing and reading information on and from the disk, a suspension for supporting the magnetic head, a carriage for holding the suspension, and a coarse actuator for driving the carriage. A magnetic disk drive having a microactuator for fine movement for driving a magnetic head, wherein a microactuator mounting portion is provided between a carriage and a suspension, wherein a window portion is provided in the microactuator mounting portion; An outer frame portion that does not intersect with the direction center line is formed of a flexible connecting member that can expand and contract in the suspension longitudinal direction, the microactuator is installed between the outer frame portions, and the mounting position of the microactuator is set at the center of the suspension longitudinal direction. Divided by line A magnetic disk device provided on one side of a mounting portion. 6. The magnetic disk drive according to claim 5, wherein the outer frame portion on the center side of the disk has a convex shape in a direction away from the center of the disk.