JPH10255413A - Head actuator device applied to disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the head positioning accuracy, by utilizing the minutely moving function of a head by an auxiliary actuator without preparing a special circuit for boosting the power source voltage and without bringing the magnetic field leaking state causing the external magnetic disturbance against the disk, in a system provided with a main actuator and auxiliary actuator for accurately making the head follow up to the objective position. SOLUTION: In the head actuator mechanism provided with the main actuator and the auxiliary actuator, an auxiliary supporting arm 32 constituting the auxiliary actuator, by which a suspension 4 is supported, is engaged with a main supporting arm 11 by an engaging part including a rotation mechanism 33. By the auxiliary supporting arm 32, the head 3 is minutely moved in the radial direction of the disk by an auxiliary VCM(voice coil motor) 30 which is arranged at the position away from the outer peripheral side of the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head actuator for positioning a target position by moving a head for recording and reproducing data in a disk radial direction in a disk recording and reproducing apparatus such as a hard disk drive. Related to the device.

[0002]

2. Description of the Related Art Heretofore, a particularly small hard disk drive (HDD) has been used as a built-in external storage device of a laptop or notebook personal computer. 2. Description of the Related Art In recent years, demands for a small-sized and large-capacity HDD have been increasing with the improvement in performance of personal computers.

In order to increase the storage capacity of an HDD, it is necessary to increase the track density and the linear recording density of a disk serving as a recording medium to increase the recording density of the disk. With the increase in recording density, a technique for positioning a head at a target position (track) to be accessed on a disk with high accuracy becomes important.

In the HDD, head positioning control is executed by a servo system which roughly performs speed control and position control. The servo system positions the head at a target position by controlling the drive of a head actuator that supports the head and moves the head in the radial direction of the disk. Therefore, in order to realize high-precision positioning control of the head, various contrivances on the mechanism of the head actuator have been attempted together with the control technology.

[0005] As shown in FIG. 12, a conventional small HDD has a rotary oscillation type head actuator 1, a disk 101, a spindle motor 102, and a voice coil, which constitute a disk drive, inside a case 100 made of aluminum alloy or the like. A motor (VCM) 2, a circuit board 103, and the like are built in. The disk 101 is a spindle motor 10
2 to rotate at high speed. The circuit board 103 mounts various circuit components such as a head amplifier for amplifying a read signal from the head 3 and supplying a write current for writing data to the disk 101 by the head 3.

The head actuator 1 supports a suspension 4 supporting the head 3, a support arm (head arm) 105 for supporting the suspension 4 and transmitting a rotational driving force, and supporting the support arm 105. V
And an actuator body 6 that is driven to rotate about the rotation shaft 6a by the driving force of the CM2.

Here, in the HDD, usually, a plurality of disks 101 are provided, and heads 3 are arranged on both surfaces of each disk 101, respectively. Therefore, the suspension 4 is provided for each head 3. The number of the support arms 5 is equal to or less than the number of the heads 3 according to the number of the heads 3. The head 3 is mounted on a slider.
The read / write operation is performed at a fixed minute interval from the surface of the first.

The VCM 2 comprises a drive coil provided on a coil frame having a substantially V-shaped structure, a permanent magnet, and an opposing yoke. The permanent magnet and the opposing yoke constituting the magnetic circuit are arranged vertically so as to sandwich the drive coil held on the coil frame of the support arm 105. The permanent magnet is supported by a holding yoke. V
The CM2 energizes a drive coil arranged in a magnetic field generated between the permanent magnet and the opposing yoke, and rotates the support arm 105 of the actuator about the rotation shaft 6a by the action of an electromagnetic force generated in the drive coil. Rock it. The actuator main body 6 is provided with a ball bearing (not shown for internal purposes) for rotationally swinging.

[0009] The servo system operates based on servo data prerecorded in a servo area of the disk 101.
The drive control of the head actuator is executed by controlling the drive current of the CM 2.

By the way, when the head actuator is driven with high accuracy and the head 3 is positioned at the target position with high accuracy, mechanical vibration generated in components such as the support arm 105 constituting the head actuator is one of the obstacles. And a spring characteristic due to a rolling friction force at the time of minute rotation of the ball bearing for rotating and swinging the actuator body 6. In addition, vibration from the outside of the HDD or H
Disturbance from the spindle motor 102 generated inside the DD also becomes an obstacle factor.

In order to position the head 3 at the target position with high accuracy, it is necessary to minimize the off-track amount of the head 3 due to such a trouble factor. For this purpose, it is necessary to make the gain crossover frequency (frequency where the gain crosses 0 dB) in the open loop characteristic of the servo system as high as possible. As a method for increasing the gain crossover frequency in the open loop characteristic of the servo system, for example, the Transactions of the Institute of Electronics, Information and Communication Engineers (Vol. J75, No. 11,
(Pages 653 to 662), there is a method described in a paper entitled "Track following control of a magnetic disk device two-stage access servo system". In this document, a main actuator mechanism (the VCM described above) for integrally moving a plurality of heads over a long stroke is described.
2), and a method of providing an auxiliary (sub) actuator for fine movement independently for each head. In this method, a piezoelectric element is used for driving the auxiliary actuator.

Further, another document (INTERMAG 19)
Also in the digest version (FC-05, 1996), similar to the above-mentioned document, in addition to the main (main) actuator mechanism for integrally moving a plurality of heads over a long stroke, the individual heads are also independently moved minutely. Auxiliary (sub)
A method of providing an actuator is described. However,
In this method, the auxiliary actuator has a configuration in which the head is minutely moved by a VCM having a magnetic circuit provided on the arm.

Incidentally, the structure of the above-described head actuator mechanism has a mode in which the drive coil 20 and the coil frame (frame) 21 constituting the VCM 2 undergo large deformation and vibration as shown in FIG. The frequency of this vibrating mode is 4 kHz, and the head 3 becomes a main structure resonance mode having a vibration peak of about 30 dB by this vibration mode, which is a detrimental factor for achieving high-precision positioning. In a normal servo system, a achievable gain crossover frequency in consideration of device variations is about 1/10 of the main structure resonance frequency. That is, the frequency band in which the head 3 can follow the servo information recorded on the disk without error is about 400 Hz. However, as the track pitch on the disk becomes narrower due to the increase in recording density, it is necessary to increase the gain crossover frequency to 1 kHz in order to reduce the error. In the case of the current structural resonance, the stability cannot be secured, and the actuator oscillates.

[0014]

As described above, various methods for positioning the head with high precision have been proposed. However, in the former method using a piezoelectric element, it is necessary to drive the piezoelectric element. Therefore, the power supply voltage needs to be increased. H installed in recent notebook computers
The power supply voltage of the DD is usually 5 V, and at most 12 V. However, a driving voltage of about 50 V is required to drive the piezoelectric element. For this reason, when a piezoelectric element is used, the supply voltage of the HDD is boosted to generate a drive voltage for the piezoelectric element. However, there is a problem that power loss occurs in the power supply during the boosting. There is also a problem with the piezoelectric element itself. That is, a laminated type (a structure in which sintered piezoelectric elements are laminated) having excellent displacement characteristics is used for the piezoelectric element used for the minute movement as described above. In this type, the reliability of the element itself deteriorates due to aging (temperature / humidity, etc.), and in the worst case, the element cannot move.

In the latter system in which the VCM is provided on the arm, there is no adverse effect due to power loss or deterioration of the piezoelectric device as compared with the system using a piezoelectric element, but a magnetic circuit is provided on the arm. Therefore, the influence of the leakage of the magnetic field by the magnetic circuit on the data recorded on the disk cannot be ignored. In the worst case, the reliability of the disk may be impaired, such as data recorded on the disk being destroyed. Further, in recent years, in order to particularly improve linear recording density, an inductive type thin film head is used as a recording head and a recording / reproducing separation type head using an MR element (magnetoresistive element) is used as a reproducing head. It is getting. In such a head, it is usually necessary to apply a bias magnetic field to the MR element in a certain position direction. This is because the MR element has a property that the resistance changes depending on the direction of the magnetic field of the magnetic data recorded on the disk. For this reason, in the case of adopting the latter method, it is necessary to provide a configuration in which the MR element and the magnetic circuit are separated from each other by a predetermined distance.

Further, in any of the above-mentioned systems, since an auxiliary actuator is provided for each of the plurality of support arms for driving, the driving circuit of the entire actuator including the main actuator is greatly increased.

It is an object of the present invention to provide a head having a main actuator and an auxiliary actuator in order to accurately follow the target position without requiring a special power supply boosting circuit for driving the auxiliary actuator. Another object of the present invention is to improve the positioning accuracy of the head by utilizing the function of minute movement of the head by the auxiliary actuator without causing a magnetic field leakage which becomes a magnetic disturbance to the disk.

Further, an object of the present invention is to provide a method using a piezoelectric element, in which the head element oscillates when the head actuator oscillates, particularly by suppressing the vibration generated in the VCM which is the driving means of the head actuator by the piezoelectric element. An object of the present invention is to prevent a situation such that positioning accuracy is reduced.

[0019]

A first aspect of the present invention is a head actuator device applied to, for example, a disk recording / reproducing device such as a hard disk device. A first support arm member for moving a head in a radial direction of the disk, and a main member for applying a rotational driving force to the first support arm member for moving each head in a range from the inner circumference to the outer circumference of the disk. A driving means, a second support arm member for minutely moving each head in the radial direction of the disk, and a minute rotation driving force for minutely moving each head in the radial direction of the disk to the second support arm member. And an auxiliary driving means.

The second support arm member supports each suspension member, engages with the first support arm member by an engaging portion including a rotation mechanism, and rotates the disk with the rotation of the first support arm member. And a mechanism for rotating each head minutely in the radial direction of the disk by a rotating mechanism. The auxiliary driving means is arranged at a position where it does not interfere with the disk, specifically, at a position distant from the outer peripheral side of the disk, and provides, for example, a voice coil motor (VC
M).

With this configuration, the main actuator including the first support arm member and the main driving means,
It is possible to realize a head actuator mechanism having a second support arm member and an auxiliary actuator including an auxiliary drive unit, and a function of minutely moving the head. This head actuator mechanism is not a method using a piezoelectric element but corresponds to a method in which a VCM is provided on an arm. However, compared to the above-described conventional method, an auxiliary driving means such as a VCM does not interfere with a disk. It is a structure arranged in. Therefore, the magnetic circuit of the auxiliary drive means can reliably prevent the magnetic field leakage (magnetic disturbance) from affecting the disk. Further, since no piezoelectric element is used, a special power supply boosting circuit for driving the auxiliary actuator is not required.

A second aspect of the present invention is a head actuator device for a disk recording / reproducing device such as a hard disk device, for example, which includes a plurality of suspension members for supporting each of the heads, and a plurality of suspension members for supporting each of the suspension members. A support arm member for moving each head in the radial direction of the disk, and a drive for rotating the support arm member in the disk radial direction about the rotation axis, and constituting a voice coil motor (VCM) A main driving unit having a coil and a coil frame; and an auxiliary unit having a piezoelectric element disposed between the coil frame and the supporting arm member for eliminating vibration generated in the supporting arm member or the main driving unit. Have

With such a configuration, the vibration in the rotation direction generated particularly in the drive coil and the coil frame of the VCM is reduced.
This can be eliminated by the piezoelectric element of the auxiliary means, and the vibration transmitted to the head can be suppressed. Specifically, when vibration occurs in the piezoelectric element, strain energy is generated, and a voltage is generated by the strain energy. With the configuration in which the terminals where the voltage is generated are short-circuited, it is possible to dissipate the strain energy inside the piezoelectric element. With this, VCM
It is possible to reduce the vibration peaks generated in the drive coil and the coil frame, and to set the gain crossover frequency of the servo system to a high frequency. Therefore, the head can accurately follow the target position on the disk, and as a result, a disk recording / reproducing apparatus with a narrow track width and a high track density can be realized.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a main part of a head actuator mechanism related to the first embodiment, and FIG. 2 is a plan view showing a main part of an HDD related to the first embodiment. (Structure of HDD) The head actuator mechanism according to the first embodiment includes a voice coil motor (hereinafter referred to as an auxiliary VCM) 30 including a drive coil functioning as an auxiliary drive unit of an auxiliary (sub) actuator and a magnetic circuit. This is a rotary swing type mechanism provided with an auxiliary support arm (second support arm) 32 for slightly moving the head 3 in the radial direction of the disk by the auxiliary VCM 30.

As shown in FIG. 2, a small HDD applied to this embodiment includes a head actuator mechanism of this embodiment, a disk 101, a spindle motor 102, and a VCM (main drive) inside a case 100 made of aluminum alloy or the like. Means), a circuit board 103, flexible printed cables (FPC) 104a, 104b, and the like. Components other than the head actuator of the present embodiment described later are the same as those of the conventional HDD (FIG. 12).
See). The case 100 is covered with a cover (not shown) for sealing.

The disk 101 is a spindle motor 102
Makes high-speed rotation at a constant speed. Circuit board 103
Mounts various circuit components such as a head amplifier for amplifying a read signal from the head 3. The FPC 104a is
A cable for supplying a drive current to the drive coil 20 of the VCM 2 for driving the main actuator body 6. The FPC 104b includes a signal line for supplying a recording / reproducing signal to the head 3, and a wiring pattern such as a cable for supplying a driving current for driving the auxiliary VCM 30 which is an auxiliary driving unit. .

In general, a plurality of disks 101 are provided. A plurality of heads 3 are arranged opposite to both sides of each disk 101. The head actuator mechanism is driven and controlled by a not-shown servo system (a servo circuit and a CPU are main components), and is configured to move in a radial direction with the head 3 floating above the disk 101. I have. The servo system executes head positioning control (servo system) including speed control and position control to position the head 3 at a target position on the disk 101 (finally at the track center). (Configuration of Head Actuator Mechanism) As shown in FIG.
A thin plate-shaped suspension 4 supporting at its tip,
Auxiliary support arm 32 for supporting suspension 4 at its tip and transmitting rotational driving force from auxiliary VCM 30
A rotation mechanism 33 for slightly rotating the auxiliary support arm 32; and a main support arm 11 integrated with the main actuator body 6 engaged with the auxiliary support arm 32 by the rotation mechanism 33. The main actuator body 6 supports the VCM 2 by supporting the main support arm 11.
With the driving force of the disk 10 around the rotation shaft 6a,
1 freely swings in the radial direction. Ball bearings 6b are provided at two locations above and below the rotating shaft 6a.

The head actuator mechanism of this embodiment has a VCM 2 as a main drive unit and an auxiliary VCM 30 as an auxiliary drive unit. The VCM 2 includes a drive coil 2 provided on a coil frame (frame) 21 having a substantially V-shaped structure.
0, a permanent magnet, and an opposing yoke. The permanent magnet and the opposing yoke constituting the magnetic circuit are arranged vertically so as to sandwich the drive coil 20 held on the coil frame 21.

As shown in FIGS. 1 and 2, the auxiliary VCM 30 is arranged at a position where it does not interfere with the outer diameter of the disk 101. The auxiliary VCM 30 includes a drive coil 31 disposed on an auxiliary support arm 32, and a magnetic circuit 35 fixed to the apparatus main body 100. The magnetic circuit 35 includes a permanent magnet and an opposing yoke. That is, the main actuator body 6 allows the head 3 to
1, the drive coil 31 and the magnetic circuit 3
5 is configured not to electromagnetically interfere with the data area of the disk 101. Note that, in principle, a configuration in which the drive coil 31 is fixed to the apparatus main body 100 and the magnetic circuit 35 is disposed on the auxiliary support arm 32 may be employed.

Here, the head actuator is shown in FIG.
As shown in (A), a plurality of main support arms 11 and auxiliary support arms 32 having a multilayer structure are provided. The plurality of suspensions 4 each support the head 3. One or two suspensions 4 are attached to each auxiliary support arm 32. The rotation mechanism 33
As will be described later, two thin plate springs 14 fixed to each auxiliary support arm 32 are configured by a cross spring mechanism in which the thin plate springs 14 are orthogonally arranged. In order to fix the thin plate spring 14 to the auxiliary support arm 32, the suspension 4
Each support member 15 is provided so as to be sandwiched between the support members 15. Further, the driving coil 31 of the auxiliary VCM 30 is
4 is fixed to the auxiliary support arm 32. Since the individual auxiliary support arms 32 are integrally formed by the fixing members 34, it is not necessary to provide the auxiliary VCM 30 for each auxiliary support arm 32 and control the driving. (Structure of Rotation Mechanism 33) The structure of the rotation mechanism 33 will be described with reference to FIGS.

FIG. 3 is a perspective view showing a schematic structure of the main actuator and the auxiliary actuator. The main actuator VCM2 generates a rotational driving force in the direction of arrow 200. Also, the auxiliary VCM3 of the auxiliary actuator
0 generates a rotational driving force in the direction of arrow 300. That is, in the main actuator, the main support arm 11 rotates in the direction of the arrow 200 about the rotation shaft 6a by the VCM2. On the other hand, in the auxiliary actuator, the auxiliary VC
The auxiliary support arm 32 is slightly rotated in the direction of arrow 300 by M30.

FIGS. 4 and 5 show a range 44 shown by a dotted line in FIG.
FIG. 8 is a diagram illustrating a rotation mechanism 33 which is 0, that is, an engagement portion between a main actuator and an auxiliary actuator. Auxiliary VCM
30 is a position that does not interfere with the disk as described above,
That is, it is arranged at a position where the magnetic interference of the drive coil and the magnetic circuit does not reach the data area of the disk. An engaging portion between the main support arm 11 of the main actuator and the auxiliary support arm 32 of the auxiliary actuator is a thin plate spring 14 which is arranged vertically for each arm and orthogonal to each other on a plane.
And a cross-spring mechanism.
With such a cross-spring mechanism, the auxiliary actuator is driven around the rotation center 33a of the rotation mechanism 33 as an axis.
The disk is slightly rotated in the radial direction of the disk. (Operation and Effect of First Embodiment) As described above, with the structure of the head actuator mechanism of the same embodiment, the auxiliary VCM 30 for driving the auxiliary actuator is arranged at a position that does not interfere with the disk 101. . The auxiliary actuator uses the rotation driving force of the auxiliary VCM 30 to rotate the rotation mechanism 33 that is an engagement portion with the main actuator.
Thus, the head 3 is moved in the radial direction of the disk 101. At this time, since the drive coil 31 and the magnetic circuit 35 constituting the auxiliary VCM 30 are located at a position distant from the disk 101, the leakage of the magnetic field due to the magnetic circuit 35 causes magnetic interference to data recorded on the disk 101. Such a situation can be reliably prevented. Further, even when a recording / reproducing separation type head using an MR element as a reproducing head is used as the head 3, since the head 3 and the auxiliary VCM 30 are separated from each other, the auxiliary VCM 3
It is possible to prevent a situation where the magnetic interference of 0 exerts on the MR element.

Further, the structure of the head actuator mechanism of the embodiment has the following excellent effects on vibration characteristics. 7 to 9 are diagrams showing analysis models of the head actuator mechanism of the embodiment. 8 and 9 are vibration mode diagrams based on the real eigenvalue analysis. FIG.
FIG. 13 is a diagram illustrating a mode (a natural frequency is about 70 Hz) in which the auxiliary actuator vibrates around the rotation center 33a in a state where the main actuator hardly moves. This is a rigid body vibration mode based on the cross-spring mechanism arranged for each arm and the mass characteristics of the auxiliary actuator (mass and moment of inertia of rotation of the rotation center 33a of the auxiliary actuator).

FIG. 9 is a diagram showing a vibration mode (natural frequency is about 3.5 KHz) attributable to the structure of the main actuator which is also found in a conventional actuator. This achieves the vibration mode achieved by the frame supporting the main actuator VCM2 and the radial spring of the ball bearing supporting the main actuator. As described above, due to this vibration mode, in the structure of the conventional actuator, it is a factor that the frequency band cannot be increased in the following control for following a narrow track (high track density).

FIGS. 10 and 11 show transmissions from the respective driving sources (VCM2 and auxiliary VCM30) to the head 3 in the track direction based on the eigenvector and the eigenvalue information obtained as a result of the above-described actual eigenvalue analysis. It is a figure showing a characteristic.
In each of FIGS. 10 and 11, (A) shows the gain characteristic with respect to the frequency, and (B) shows the phase characteristic with respect to the frequency.

In FIG. 10, the main actuator VCM
FIG. 4 is a transfer characteristic diagram showing the displacement of the head 3 in the track direction by inputting the coil generation force in the drive generation direction 200 of FIG. 2 into the analysis model (see FIG. 3). Frequency is several tens Hz
In the vicinity, the rolling spring characteristic of the ball bearing has an effect of the rotation spring characteristic. In the vicinity of 3.5 KHz, the main resonance achieved with the frame supporting the main actuator VCM2 or the radial spring of the ball bearing appears. (See FIG. 9). On the other hand, in FIG. 11, the rigid body vibration mode by the cross-spring mechanism is 7
Although it is seen around 0 Hz, no large vibration peak appears in the track direction up to around 8 KHz. In addition, auxiliary VCM3
Since the reaction force of 0 is not transmitted to the main actuator, the main resonance mode of the structure of the main actuator around 3.5 KHz shown in FIG. 10 does not appear, so that an unnecessary vibration peak does not appear.

Here, in the arrangement of the auxiliary support arm 32 of the auxiliary actuator and the drive coil 31 of the auxiliary VCM 30, the position of the center of gravity is set to the center position of the rotation mechanism 33 in order to minimize the movement against external translational acceleration. Must match.

As described above, according to the present embodiment, the inertia moment of the auxiliary actuator can be reduced, and the mechanical resonance frequency can be increased in the transmission characteristic from the rotation generation force of the auxiliary VCM 30 to the head 3. Further, the head 3 can follow the target track on the disk 101 without being affected by the rolling friction characteristics in the minute rotation region generated by the ball bearing 6b of the arm body 6 of the main actuator. Further, as described above, since the auxiliary VCM 30 is arranged at a position away from the disk 101 and not affected by magnetic interference, a magnetic disturbance component due to magnetic leakage is applied to the MR element of the head 3 and the data area of the disk. Is suppressed. Therefore, as a result, a higher recording density can be achieved in the linear recording density direction. (Modification of this Embodiment) FIG. 6B is a diagram showing a modification of the configuration of the leaf spring 14 in the rotation mechanism 33 of the auxiliary actuator of this embodiment. In this modification, one leaf spring 14 is attached to the auxiliary support arm 32 of the auxiliary actuator.
The direction of the leaf spring is 4
It is configured to be shifted by 5 degrees. In the present embodiment, the number of the auxiliary support arms 32 is an odd number, the central auxiliary support arm 32 becomes unnecessary, the inertia moment of the main actuator on the coarse movement side is reduced, and the feed control time of the head actuator is reduced. Reduction can be achieved. Although the case where the number of the auxiliary support arms 32 is an odd number has been described, the leaf springs 14 may be configured at least two at positions shifted by 45 degrees, and the configuration may be changed as appropriate. (Second Embodiment) FIGS. 13 and 14 are diagrams related to the second embodiment. The head actuator mechanism of the present embodiment is a rotation swing mechanism in which a VCM composed of a drive coil and a magnetic circuit is used as a main drive unit and an auxiliary drive unit using a piezoelectric element is added.

As shown in FIG. 14, a small HDD applied to the present embodiment includes a head actuator mechanism, a disk 101, a spindle motor 102, a VCM 2 and a circuit board in a case 100 made of an aluminum alloy or the like. 103, a flexible cable (FPC) 104, and the like. The components other than the head actuator of the present embodiment, which will be described later, are the same as those of the conventional HDD (see FIG. 12). The case 100 is covered with a cover (not shown) for sealing.

The disk 101 is a spindle motor 102
Makes high-speed rotation at a constant speed. Circuit board 103
Implements various circuit components such as a head amplifier for amplifying a reproduction signal from the head 3 and writing the data on a disk. The FPC 104 is for driving a drive current on the drive coil 20 of the VCM 2 for driving the main actuator body 6, and for driving signals used for recording and reproduction of the head 3 and for driving the piezoelectric elements 8 a and 8 b as auxiliary driving means. And a wiring pattern such as a cable. Usually, a plurality of disks 101 are provided. A plurality of heads 3 are arranged opposite to both sides of each disk 101. The head actuator mechanism is driven and controlled by a not-shown servo system (a servo circuit and a CPU are main components), and is configured to move in a radial direction with the head 3 floating above the disk 101. I have. The servo system executes head positioning control (servo system) including speed control and position control to position the head 3 at a target position on the disk 101 (finally at the track center). (Structure of Head Actuator Mechanism) As shown in FIG. 13, the head actuator mechanism of this embodiment has a thin plate-shaped suspension 4 supported at the tip by a head 3.
And a support arm 11 for supporting the suspension 4 at the distal end and transmitting a driving force, and an actuator body 6. The actuator body 6 supports the support arm 11 and rotates the rotation shaft 6 a by the driving force of the VCM 2.
About the disk 101 in the radial direction of the disk 101. Ball bearings 6b are provided at two locations above and below the rotary shaft 6a.

The head actuator mechanism of the present embodiment has a structure in which VCM 2 as main driving means and piezoelectric elements (piezo elements PZT) 8a and 8b as auxiliary driving means are provided. The VCM 2 includes a drive coil 20 and a coil frame (frame) 21 for holding the drive coil 20.
And a magnetic circuit including a permanent magnet and a facing yoke. The permanent magnet and the opposing yoke constituting the magnetic circuit are arranged vertically so as to sandwich the drive coil 20 held by the coil frame 21. Each coil frame 21 is joined at both ends of the drive coil frame 20.

Piezoelectric elements 8a and 8b serving as auxiliary driving means
Are arranged at a total of two places on both sides of the coil frame 21,
It is joined so as to be connected between the actuator main body 6 and the coil frame 21. That is, the piezoelectric element 8
Reference numerals a and 8b denote bending vibration modes in the access direction generated by the coil frame 21 and the drive coil 20, and are arranged at the base of the actuator body 6 at a location where the strain energy is large.

With the head actuator mechanism having such a structure, when a vibration mode is generated in the drive coil 20 and the coil frame 21 by driving the VCM 2 (see FIG. 16), the piezoelectric elements 8a and 8b vibrate. Drive to eliminate components. Therefore, the vibration generated on the VCM 2 side is canceled by the piezoelectric elements 8a and 8b, and is not transmitted to the actuator main body 6 side. As a result, the transmission characteristic of the head 3 with respect to the rotational driving force generated from the VCM 2 becomes a flat characteristic up to a high frequency region. That is, the vibration peak generated in the drive coil 20 and the coil frame 21 of the VCM 2 can be reduced, and the gain crossover frequency of the servo system can be set to a higher frequency. Therefore, the head 3 can accurately follow the target position on the disk 101, and as a result, a disk recording / reproducing apparatus having a narrow track width and a high track density can be realized. (Modification 1 of this embodiment) The modification 1 has the same structural configuration as that of this embodiment. That is, the piezoelectric elements 8a and 8b, which are auxiliary driving means, are arranged at two places on both sides of the coil frame 21, and the actuator body 6 and the coil frame 2
1 is connected. further,
Although not shown, the first modification has a configuration in which the electrodes of the piezoelectric elements 8a and 8b are short-circuited. Hereinafter, the piezoelectric elements 8a,
8b will be described.

As described above, when the vibration mode is excited in the drive coil 20 and the coil frame 21 by driving the VCM 2 (see FIG. 16), the piezoelectric elements 8a, 8b generates strain energy. The distortion energy is converted into a voltage by the piezoelectric elements 8a and 8b as a piezoelectric effect. Here, by short-circuiting the electrodes of the piezoelectric elements 8a and 8b, the converted voltage is fed back to the piezoelectric elements 8a and 8b, and distortion energy is generated inside the piezoelectric elements 8a and 8b. Therefore, in the piezoelectric elements 8a and 8b, a phenomenon occurs in which the generated distortion components cancel each other, and
As a result, the strain energy is dissipated inside the piezoelectric elements 8a and 8b. This makes it possible to reduce the vibration peaks generated in the drive coil 20 and the coil frame 21 of the VCM 2 and to set the gain crossover frequency of the servo system to a high frequency. Therefore, the head 3 can accurately follow the target position on the disk 101, and as a result, a disk recording / reproducing apparatus having a narrow track width and a high track density can be realized. (Modification 2 of this embodiment) FIG. 15 is a diagram showing Modification 2 of this embodiment. In the second modification, as shown in FIG. 15, the piezoelectric elements 8a and 8b serving as auxiliary ratchet driving means are arranged at positions orthogonal to the coil frame 21. Even with such an arrangement of the piezoelectric elements 8a and 8b, the effects described above can be obtained.

[0045]

As described above, according to the first aspect of the present invention, in order to cause a head to accurately follow a target position, a method for driving an auxiliary actuator in a system having a main actuator and an auxiliary actuator is provided. Improves the positioning accuracy of the head by using the head's small movement function with the auxiliary actuator, without the need for a special power supply booster circuit and without causing a magnetic field leakage that may cause magnetic disturbance to the disk Can be done. Further, the moment of inertia of the auxiliary actuator can be reduced, and the mechanical resonance frequency can be increased in the transmission characteristic from the rotation generating force of the auxiliary driving means to the head. Therefore, as a result, a higher recording density can be achieved in the linear recording density direction.

According to the second aspect of the present invention, in a system using a piezoelectric element, the head element oscillates by suppressing the vibration particularly generated in the VCM which is the driving means of the head actuator by the piezoelectric element. Thus, it is possible to prevent a situation such that the positioning accuracy of the head is reduced. In other words, the vibration peak generated from the actuator driving means is reduced, and the open loop characteristic of the head positioning control system from the main actuator has no mechanical main resonance mode and has a flat characteristic up to a high frequency band. Can be. By realizing a good servo system up to the high frequency band, the head can accurately follow the target position on the disk, and as a result, a disk recording / reproducing device with a narrow track width and a high track density can be realized. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a head actuator mechanism according to a first embodiment of the present invention.

FIG. 2 is an exemplary view showing a main part of the HDD related to the embodiment.

FIG. 3 is an exemplary perspective view for explaining the structure of an auxiliary actuator related to the embodiment;

FIG. 4 is an exemplary perspective view for explaining the structure of an auxiliary actuator related to the embodiment;

FIG. 5 is an exemplary view for explaining the structure of an auxiliary actuator according to the embodiment;

FIG. 6 is a side view showing the main part of the head actuator mechanism related to the embodiment.

FIG. 7 is a view showing an analysis model of a head actuator mechanism related to the embodiment.

FIG. 8 is a view showing an analysis model of a head actuator mechanism related to the embodiment.

FIG. 9 is a view showing an analysis model of a head actuator mechanism related to the embodiment.

FIG. 10 is a vibration characteristic diagram showing a displacement response result of the head related to the embodiment.

FIG. 11 is a vibration characteristic diagram showing a displacement response result of the head related to the embodiment.

FIG. 12 is a perspective view showing a main part of a conventional HDD.

FIG. 13 is a view showing a main part of a head actuator mechanism related to the second embodiment.

FIG. 14 is an exemplary view showing a main part of an HDD related to the second embodiment;

FIG. 15 is a diagram showing a modification of the second embodiment.

FIG. 16 is a diagram showing a deformation vibration mode of a VCM of a conventional head actuator mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Head actuator mechanism 2 ... Voice coil motor (VCM) 3 ... Head 4 ... Suspension 6 ... Actuator main body 6a ... Rotating shaft 6b ... Ball bearing 8a, 8b ... Piezoelectric element (auxiliary drive means) 11 ... Main support arm (1st 14 ... leaf spring (cross-spring mechanism) 30 ... auxiliary VCM (auxiliary drive means) 31 ... magnetic circuit 32 ... auxiliary support arm (second support arm) 33 ... rotating mechanism 35 ... magnetic circuit 101 ... disk 100: Case 102: Spindle motor 103: Circuit board 104a, 104b: Flexible printed cable (FPC)

Claims (7)

[Claims] 1. A head actuator device of a disk recording / reproducing apparatus for mounting a plurality of heads for recording / reproducing data on a disk and moving each of the heads in a radial direction of the disk to position the head at a target position. A plurality of suspension members for supporting the respective heads; a first support arm member for moving the respective heads in the radial direction of the disk by rotational driving; and a first support arm member. A main drive unit for applying a rotational driving force for moving each of the heads in a range from the inner circumference to the outer circumference of the disk; a main support unit that supports the suspension members, and the first support arm member includes a rotation mechanism. The first support arm member is driven to rotate in the radial direction of the disk along with the rotation of the first support arm member; and Second to minute movement of the respective head by rolling mechanism in the radial direction of said disk
And a support arm member that is disposed at a position where the disk does not interfere with the disk and that applies a minute rotation driving force to the second support arm member to slightly move each head in the radial direction of the disk. A head actuator device comprising: a driving unit. 2. The head actuator device according to claim 1, wherein said main driving means and said auxiliary driving means are each constituted by a voice coil motor having a coil and a magnetic circuit. 3. The head actuator device according to claim 1, wherein the engaging portion is configured by a cross spring mechanism in which leaf springs are arranged orthogonally. 4. The second support arm member has a substantially linear shape, engages with the first support arm member at a predetermined angle, and is disposed at a position distant from the outer peripheral side of the disk. 3. The device according to claim 1, wherein said auxiliary driving means is configured to be engaged with said auxiliary driving means.
The head actuator device according to claim 3. 5. A method according to claim 1, wherein said auxiliary driving means comprises a voice coil motor having a coil attached to said second support arm member and a magnetic circuit attached to a main body of said disk recording / reproducing apparatus. The head actuator device according to claim 1 or 2, wherein 6. A head actuator device of a disk recording / reproducing apparatus for mounting a plurality of heads for recording / reproducing data on a disk, moving each head in a radial direction of the disk, and positioning the head at a target position. A plurality of suspension members for supporting each of the heads; a support arm member for supporting each of the suspension members and moving each of the heads in a radial direction of the disk around a rotation axis; Main driving means for driving the supporting arm member to rotate in the radial direction of the disk about a rotation axis, the main driving means having a driving coil constituting a voice coil motor and a coil frame supporting the driving coil, The support arm member is disposed between the coil frame and the support arm member. Head actuator device characterized by being provided with an auxiliary means having a piezoelectric element for eliminating the vibrations generated in the main drive means. 7. The auxiliary means has means for short-circuiting between terminals at which a voltage is applied to the piezoelectric element due to vibration generated in the support arm member or the main driving means, and dissipates distortion energy generated in the piezoelectric element. 7. The head actuator device according to claim 6, wherein the vibration is suppressed from being transmitted to each of the heads by dissipating the head.