JP2000357376A - Head actuator mechanism - Google Patents

Abstract

(57) [Problem] Conventionally, two types of actuators, one for coarse movement and one for fine movement, have been required to coarsely and finely move a magnetic head. SOLUTION: A piezoelectric body 6 to which a predetermined AC voltage is applied.
And an elastic body 5 bonded to one surface of the piezoelectric body 6
A movable body 11 connected to the movement of the projected body 15, a support arm 2 connected to the movable body 11, and a magnetic head 3 provided on the support arm 2. A voltage is applied to the piezoelectric body 6 so that a predetermined standing wave is formed in a circumferential direction substantially at a predetermined point in the plane of the piezoelectric body 6, and the voltage is applied to the piezoelectric body 6 via the protrusion 15. The moving body 11 is rotated in a plane substantially perpendicular to the vibration direction of the wave, and the magnetic head 3 is rotated together with the rotating movement of the moving body 11. The amplitude of the AC voltage applied to the piezoelectric body 6 and / or
Alternatively, by controlling only the frequency, the magnetic head 3 can be coarsely moved or finely moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head actuator mechanism for moving a head for recording and reproducing information in a disk device such as a hard disk device using a disk as an information recording medium.

[0002]

2. Description of the Related Art In recent years, the precision of information equipment has been advanced.
There is an increasing demand for an actuator that can control the movement of a minute distance. For example, an actuator capable of controlling the movement of a minute distance is required for focus correction and tilt angle control of an optical system, position control of a printing device of a printer, and head position of a magnetic disk device.

[0003] Among such information devices, the magnetic disk device is one of the key devices of multimedia devices that have rapidly expanded in market in recent years. In multimedia equipment, in order to handle a large amount of images and sounds at a high speed, development of an apparatus having a larger storage capacity is desired. Increasing the capacity of a magnetic disk device as one of such devices is generally realized by increasing the storage capacity per disk. However, in order to increase the recording density of a magnetic disk drive without changing the disk diameter, it is essential to increase the number of tracks per unit length (TPI), that is, to narrow the track width. . As described above, when the storage density is rapidly increased, the track pitch is sharply reduced. Therefore, it is a technical problem how to accurately determine the position of the head element that performs reading and writing on the recording track. There is a need for a head actuator.

Conventionally, in a magnetic disk drive, in order to perform high-precision positioning, an attempt has generally been made to improve the rigidity of a movable portion such as a carriage and increase the main resonance frequency in the in-plane direction. However, there is a limit to the improvement of the resonance point, and even if the in-plane resonance point of the movable part can be greatly increased, resonance occurs because the bearing supporting the movable part exhibits spring characteristics. Therefore, it was difficult to increase the servo band.

As one of means for solving these problems, it has been proposed to provide a second actuator for track following at the tip of the arm of the head actuator. The second actuator is capable of minutely moving the head provided at the distal end of the arm independently of the operation of the head actuator.

For example, Japanese Unexamined Patent Publication No. 3-69072 discloses a disk drive 200 in which a second actuator 203 is provided at the tip of an arm 202 in addition to the main actuator 201 of the disk drive 200 as shown in FIG. ing. The second actuator 203 is provided with two laminated piezoelectric elements 207 which are formed by laminating a plurality of piezoelectric elements displaced in the thickness direction on the moving plane of the head 204. By using the piezoelectric element 207, the minute displacement control of the head 204 in the plane of the moving plane of the head 204 can be performed.

The piezoelectric element 207 will be further described. In the second actuator 203, the laminated piezoelectric element 20
7 are arranged in the extension direction of the arm 202, and 2
A swing center spring 205 is provided between the piezoelectric elements 207 as shown in FIG. The swing center spring 205 is provided with a plurality of slits 2 inward from both sides of the center arm 206 in a direction perpendicular to the longitudinal direction of the center arm 206.
08 are provided alternately. With the plurality of slits 208, the center arm 206 functions as a spring, and when the laminated piezoelectric element 207 is pressurized, it expands and contracts accordingly. In addition, the laminated piezoelectric element 2
07 and the arm 202 are electrically insulated by an insulating material. Further, although not shown, an electrode is provided on the piezoelectric element 207, and a lead wire is drawn out from the electrode and passed through the electrode. A drive voltage is applied to the laminated piezoelectric element 207.

[0008]

The head moving mechanism having the above-described structure requires two types of actuators, a rotary actuator for coarse movement and a piezoelectric actuator for fine movement, and furthermore, these two actuators. Have to be controlled simultaneously.

To use a piezoelectric actuator for fine movement, a laminated piezoelectric element 207, a pressurizing spring mechanism (a swing center spring 205 and a plurality of slits 208) machined with high precision, a piezoelectric element There is a problem that a lead wire or a wire for providing a driving voltage to the 207 is required. There is also a problem that it is difficult to manufacture the piezoelectric element 207.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a head actuator mechanism that solves the above-mentioned conventional problems and performs both coarse and fine movements of a head.

[0011]

In order to solve the above problems, a first aspect of the present invention (corresponding to claim 1) is to provide a piezoelectric substrate to which a predetermined voltage is applied, and one surface of the piezoelectric substrate. A moving body interlocked with the movement of the moving body, an arm member connected to the moving body, and a head provided on the arm member, wherein the moving body moves in a vibration direction of the piezoelectric substrate due to the application of the voltage. The head rotates in a plane substantially perpendicular to the moving body, and the head moves in a rotational movement plane of the moving body.
Alternatively, the head actuator mechanism moves on a plane substantially parallel to the rotational movement plane.

[0012]

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

(First Embodiment) First, a first embodiment of the present invention will be described.
The configuration of the head actuator mechanism according to the embodiment will be described together with the operation with reference to the drawings.

FIG. 1 is a plan view of a magnetic disk drive according to a first embodiment of the present invention. In FIG. 1, 1 is a head actuator, 2 is a support arm including a suspension, 3 is a magnetic head, and 4 is a magnetic recording disk. The magnetic head 3 attached to the tip of the support arm 2 moves on the magnetic recording disk 4 in the direction of the arrow by the rotational movement of the head actuator 1 attached to the other end of the support arm 2, and the information is moved to a predetermined position. Or read information recorded at a predetermined position.

Next, FIG. 2 shows a cross section of the head actuator mechanism according to the first embodiment of the present invention. In the drawing, 1 is a head actuator, 2 is a support arm including a suspension, 3 is a magnetic head, 5 is an elastic body, 6 is a piezoelectric body made of piezoelectric ceramic, 7 is an elastic body 5 and a piezoelectric body 6
, A vibration member, a support member, 9 a friction member, 10 an elastic member, 11 a moving member including the friction member 9 and the elastic member 10, 12 a pressure spring, 13 a bearing, 14
Is a retaining ring, and 15 is a projection formed on the surface of the vibrating body 7.

The vibrating body 7 is formed by bonding a disk-shaped piezoelectric ceramic as the piezoelectric body 6 to one of the disk surfaces of a disk-shaped elastic body 5 made of stainless steel or the like. FIG.
In the figure, the piezoelectric body 6 and the elastic body 5 are separately displayed on the left and right, but each of the piezoelectric body 6 and the elastic body 5 is a disk having a hole in the center. Further, the vibrating body 7 is held at the center by the support body 8. Although not shown in FIG. 2, electrodes are provided on both surfaces of the piezoelectric body 6. The electrodes will be described later.

A moving body 11 composed of a friction material 9 made of a wear-resistant material and an elastic body 10 made of stainless steel or the like is pressed on the vibrating body 7 via a friction material 9 by a pressure spring 12. Are in pressure contact with the projections 15 of FIG. Pressure spring 1
Numeral 2 is fixed in a state where a set amount of deflection is given so that a set pressing force is obtained by the retaining ring 14. In order to transmit the rotary motion to the moving body 11 without loss, the bearing 1
3 are arranged.

Next, FIG. 3 illustrates an example of an electrode provided on the surface of the piezoelectric body 6 of the head actuator mechanism shown in FIG. 2 which is not opposed to the elastic body 5 and an example of polarization of the piezoelectric body 6. FIG. The electrodes are arranged in each of the fan-shaped regions 61 to 66 in FIG. In addition, each area 61-6
The symbols “+” and “−” written in the
The polarization directions of the regions 61 to 66 are all in the thickness direction of the piezoelectric body 6, but the polarization directions of the “−” regions 61, 63, 65 and the “+” region 62, 6
The polarization directions of 4, 66 mean that they are opposite to each other. In this example, a vibration mode (hereinafter, referred to as a zero-order mode) having no nodal circle in the radial direction and a standing wave of three waves in the circumferential direction are provided for a circle having the center substantially at the point 60 of the piezoelectric body 6. Is an example designed to be excited. Also,
Although not shown, electrodes are disposed on substantially the entire surface of the piezoelectric body 6 facing the elastic body 5.

Next, with reference to FIG. 4, the position where the projection 15 formed on the surface of the vibrating body 7 is arranged will be described. FIG. 4 is a diagram obtained by adding a portion for explaining the position where the protrusion 15 is arranged to FIG. The protrusions 15 are located on the surface of the elastic body 5 on the side not facing the piezoelectric body 6 and are within the two concentric circles 15a to 15a indicated by broken lines in FIG.
It is provided at a position facing the hatched area described as 5l. That is, each of the protrusions 15a to 15l is provided at a position apart from each of the nodes of the above-described standing wave by a predetermined length shorter than a quarter wavelength of the standing wave.

When a voltage V ₁ represented by the following equation (1) is applied to the electrodes arranged on both sides of the piezoelectric body 6 of the actuator mechanism configured as described above, the vibration body 7 is subjected to the following equation (2). A standing wave of bending vibration represented by

[0021]

(Equation 1)

[0022]

(Equation 2) FIG. 5 shows the protrusion 1 when a standing wave is excited on the vibrator 7.
5 shows a state of exercising. FIG. 2 shows a cross section of one standing wave in the circumferential direction. Specifically, FIG.
Protrusions 15a provided at positions corresponding to 5a and 15b
15a and 15b show a cross section showing the movement. In FIG.
For convenience of explanation, the protrusions 15g and 15h are not shown.

As described above, the projection 15 is
Above, it is formed at a position shifted in the circumferential direction by a distance of less than 1/4 wavelength from the circumferential electrode boundary portion of the piezoelectric body 6 constituting the vibrating body 7, so that the vibrating body 7 is excited. The tip of the projection 15 reciprocates as indicated by the black arrow in the drawing due to the bending vibration. Since the moving body 11 is in pressure contact with the projection 15, the moving body 11 moves in a fixed direction (in the direction indicated by the white arrow in FIG. 5) in a plane substantially perpendicular to the vibration direction of the piezoelectric body 6. Exercise). That is, it rotates counterclockwise in FIGS. Further, the movable body 11 has a support arm 2 having a magnetic head 3 attached to its tip.
Is attached, the magnetic head 3 can be moved.

Up to this point, the rotation of the moving body 11 in one direction has been described with reference to FIG. 5, but as shown in FIG. 6, the projections 15g and 15h reciprocate as indicated by black arrows. Therefore, it also rotates in the direction opposite to the white arrow in FIG. 5, that is, clockwise in FIGS. Therefore, moving body 1
The magnetic head 3 attached to the support arm 2 connected to the magnetic disk 1 can be rotated clockwise or counterclockwise on a plane parallel to the magnetic recording disk 4 with the head actuator 1 shown in FIG. It will rotate. In FIG. 6, the projections 15a and 15b are not shown for convenience of explanation.

However, the moving body 1 is attached to the projections 15a to 15f.
When rotating 1, the protrusions 15 g to 15 l
It is necessary to perform control to prevent the rotation of the moving body 11 when rotating the moving body 11 to the projections 15g to 15l, and to prevent the rotation of the projections 15a to 15f when the moving body 11 is rotated. There is. In other words, when the projections 15a to 15f are to be brought into contact with the moving body 11, the projections 15g to 15l are prevented from being brought into contact with the moving body 11, and the projections 15g to 151 are attached to the moving body 11. When trying to contact, protrusions 15a to 15
It is necessary to perform control so that f does not contact the moving body 11. For example, in FIG.
4 and 66, and “−” regions 61 and 6
The magnitude of the voltage to be applied to the electrodes arranged at 3, 65 is changed according to the direction in which the moving body 11 is to be rotated, or, for example, at a certain timing, the “+” area 62,
A voltage is applied to 64 and 66, and at that timing, voltage application is controlled such that no voltage is applied to the “−” regions 61, 63 and 65. Further, for example, when all the projections 15a to 15l are formed of a piezoelectric material and one of the projections 15a to 15f is to be brought into contact with the moving body 11,
By increasing the length of the projections 15a to 15f,
1 while the projections 15g to 15l
Voltage control to shorten the length of the projections 15g to 15l so as not to contact with the projections 15a to 15l,
Similarly, when the projections 15g to 15l are to be brought into contact with the moving body 11, the lengths of the projections 15g to 15l are increased and the projections 15g to 15l are brought into contact with the moving body 11, and the other projections 15a to 15l are provided.
So that the projections 15a to 15
The voltage application control for shortening the length of each of the protrusions 15a-1
Perform 5 l.

In the above-described configuration, the minimum value of the amount of extrusion by which the vibrating body 7 pushes the moving body 11 in the rotation direction is determined by the finishing limit of the surface roughness in the processing of the vibrating body 7 and the moving body 11, In consideration of the elastic deformation of the friction material 9, it is generally about 0.01 μm. That is, the minimum rotation angle of the head actuator 1 is 0.000046
Degree. In this configuration, the support arm 2 is attached to the head actuator 1. Assuming that the length of the support arm 2 is 40 mm, the minimum movement amount of the magnetic head 3 attached to the tip of the support arm 2 is about 0.03 μm. Thus, an actuator mechanism having a very small resolution can be realized.

Further, the present actuator mechanism continuously excites the vibration on the vibrating body 7 so that
Since a rotation speed of rpm can be realized, it can also function as an actuator for moving the magnetic head 3 in the range of 8.3 to 12.4 mm in 1 ms.

From the above, it is possible to realize a high-performance actuator mechanism that can simultaneously perform fine movement and coarse movement.

In addition, in the conventional actuator using a piezoelectric body, the resonance frequency of the actuator in the direction in which the magnetic head 3 is moved restricts the control frequency, but the actuator according to the first embodiment of the present invention In the mechanism, since there is no resonance vibration of the actuator in the direction in which the magnetic head 3 is moved, the control frequency of the actuator mechanism is limited only by the resonance frequency of the support arm 2. , It has a function of enabling high-speed seek.

Further, when the magnetic head 3 shown in FIG. 1 is disposed vertically above the moving body 11 and the piezoelectric body 6, that is, the magnetic recording disk 4 surface is made perpendicular to the ground surface. When installed, a large rotational moment is generated due to the weight of the support arm 2 and the magnetic head 3. In that case, in the actuator mechanism of the first embodiment shown in FIG. 1, the movable body 11 is rotated in consideration of a rotational moment generated by the support arm 2 and the magnetic head 3 being affected by gravity. It is necessary to respond to.

Therefore, as shown in FIG.
And a balancer 16 for suppressing a rotational moment generated when the magnetic head 3 is affected by gravity.
Is disposed at a position symmetrical to the combined center of gravity of the support arm 2 and the magnetic head 3 with respect to the substantially center of rotation of the head actuator 1, so that the rotational moment due to weight can be significantly reduced, and a small starting torque The magnetic head 3 can be moved even by the head actuator 1 having only the holding torque. Further, since the pressing force for bringing the moving body 11 into pressure contact with the protrusion 15 formed on the vibrating body 7 can be reduced, wear of the tip of the protrusion 15 and the friction material of the moving body 11 is also reduced. There is also an advantage that the life can be greatly extended because it is suppressed.

In the first embodiment described above, as described with reference to FIG. 3, the case where the wave formed on the vibrating body 7 is a 0-order mode wave in the radial direction has been described.
There is no need to stick to the 0th order in the radial direction. Also, the circumferential direction is 3
There is no need to stick to the waves.

In the first embodiment described above, the polarization directions of the “+” region and the “−” region of the piezoelectric body 6 in FIG. 3 are opposite to each other. There may be. In this case, the phase of the AC voltage applied to the area of “+” is set to be one phase less than the phase of the AC voltage applied to the area of “−”.
Must be delayed or advanced by 80 degrees. Even in such a case, a standing wave is generated in the vibrating body 7. In short, a voltage is applied to the piezoelectric body 6 so that a predetermined standing wave is formed in the circumferential direction substantially at the point 60 of the piezoelectric body 6, and the voltage is applied in the circumferential direction of the vibrating body 7. What is necessary is just to generate a standing wave.

Further, in the above-described first embodiment,
Although the installation position of the protrusion 15 has been described with reference to FIG. 4, the installation position of the protrusion 15 is not limited to the position described with reference to FIG. The number, shape, and material of the projections 15 are not limited. In short, the protrusion 15 only needs to rotate the moving body 11 in conjunction with the standing wave excited by the vibration body 7.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The configuration of the head actuator mechanism according to the embodiment will be described together with the operation with reference to the drawings.

FIG. 8 shows a cross section of a head actuator mechanism according to a second embodiment of the present invention. In FIG.
Is an elastic body, 6 is a piezoelectric body made of piezoelectric ceramic, 7 is a vibrating body formed by bonding the piezoelectric body 6 to the elastic body 5, 8
Is a support, 9 is a friction material, 10 is an elastic body, and 11 is a friction material 9
A pressure spring, 13 a bearing, 14 a retaining ring, and 15 a protrusion formed on the surface of the vibrator 7. The configuration of the head actuator mechanism according to the second embodiment of the present invention is the same as that of the first embodiment of the present invention.
Although the configuration of the head actuator mechanism of the second embodiment is the same as that of the first embodiment, the operation of the piezoelectric body 6 and the operation of a portion affected by the operation are different from those described in the first embodiment.

The vibrating body 7 is formed by bonding a disk-shaped piezoelectric ceramic as the piezoelectric body 6 to one of the disk surfaces of a disk-shaped elastic body 5 made of stainless steel or the like. Each of the piezoelectric body 6 and the elastic body 5 is a disk having a hole at the center. Further, the vibrating body 7 has a support 8
Is held by Although not shown, electrodes are provided on both surfaces of the piezoelectric body 6.

A moving body 11 composed of a friction material 9 made of a wear-resistant material and an elastic body 10 made of stainless steel or the like is pressed on the vibrating body 7 via a friction material 9 by a pressure spring 12. Is in pressure contact with the protrusion 15 formed on the substrate.
The pressurizing spring 12 is fixed with a set amount of deflection so that a set pressing force is obtained by the retaining ring 14.
A bearing 13 is provided to transmit the rotary motion to the moving body 11 without any loss.

Next, FIG. 9 illustrates an example of the electrodes provided on the surface of the piezoelectric body 6 of the head actuator mechanism shown in FIG. 8 which is not opposed to the elastic body 5 and an example of the polarization of the piezoelectric body 6. FIG. The electrodes are arranged in each of the fan-shaped regions 91 to 102 in FIG. In addition, each region 91 to
The symbols "+" and "-" written in 102 are shown in FIG.
Is a symbol having the same meaning as that described using.
That is, the regions 91 to 102 of the piezoelectric body 6 are each “+”.
This is a region where the polarization of the region and the region of “−” are opposite to each other in the thickness direction of the piezoelectric body 6. Note that FIG.
0 in the radial direction with respect to a circle having the point 90 substantially at the center.
Next, it is a diagram showing an example designed so that a third-order elastic wave is excited in the circumferential direction. In the figure, an electrode group A represented by a white background and an electrode group B represented by hatching are circles. They are displaced in the circumferential direction by an amount corresponding to １ ／ wavelength. Also,
Although not shown, electrodes are disposed on substantially the entire surface of the piezoelectric body 6 facing the elastic body 5.

The protrusion 15 formed on the surface of the vibrating body 7 is a surface of the elastic body 5 which is not opposed to the piezoelectric body 6 and is indicated by "+" or "-" in FIG. It is provided at a position facing the place where the symbol is attached.

The voltage V represented by (Equation 1) is applied to the electrode group A of the piezoelectric body 6 of the actuator mechanism configured as described above.
_{When 1} is applied and a voltage V ₂ expressed by (Equation 3) is applied to the electrode group B, a traveling wave of a bending vibration traveling in the circumferential direction expressed by (Equation 4) is applied to the vibrating body 7. Get excited.

[0042]

(Equation 1)

[0043]

(Equation 3)

[0044]

(Equation 4) FIG. 10 shows a state in which the moving body 11 is driven by frictional force by the traveling wave excited on the vibrating body 7 to move.

A point C on an arbitrary surface of the vibrating body 7 makes an elliptical motion of a long axis 2w and a short axis 2u by the traveling wave of the bending vibration.
When the moving body 11 pressurized on the vibrating body 7 comes into contact with the vicinity of the apex of the ellipse, the moving body 11 rotates at a speed of ω × u in a direction opposite to the traveling direction of the wave. I do. Since the ratio of the major axis to the minor axis of the elliptical motion can be controlled by the thickness of the vibrating body 7 and the height of the projection 15, the projection 15
Is increased, the moving speed of the moving body 11 can be improved. Furthermore, since the support arm 2 having the magnetic head 3 attached to the tip thereof is attached to the moving body 11, the magnetic head 3 can be moved.

In order to reverse the rotation direction of the moving body 11, a voltage may be applied to each part of the piezoelectric body 6 so as to reverse the traveling direction of the traveling wave formed on the vibrating body 7.

As described above, in the present embodiment, the first
In addition to obtaining the same effects as those of the first embodiment, the traveling wave is excited on the vibrating body 7, so that the rotation of the moving body 11 can be made smooth. Therefore, the movement of the magnetic head 3 can be made smoother, and a higher-performance head actuator mechanism can be provided.

Further, by disposing a balancer in the same manner as in the first embodiment, the same effect as in the first embodiment can be obtained, that is, in a case where the surface of the magnetic recording disk 4 is in the vertical direction. Also the support arm 2 and the magnetic head 3
Can be suppressed the rotational moment caused by the influence of gravity.

Further, in this embodiment, the case where the wave formed on the vibrating body 7 is a traveling wave of the 0th-order mode in the radial direction has been described, but it is not necessary to stick to the 0th-order mode in the radial direction. Similarly, it is not necessary to stick to three waves in the circumferential direction. In short, a voltage is applied to the piezoelectric body 6 so that a predetermined traveling wave is formed in the circumferential direction substantially at the point 90 of the piezoelectric body 6, and the traveling wave is applied in the circumferential direction of the vibrating body 7. Only needs to be generated.

In the above-described second embodiment, the moving body 11 is rotated by the projection 15 provided on the vibrating body 7. However, the distance between the vibrating body 7 and the moving body 11 is set to an appropriate distance. In this case, there is no need to provide the projection 15. Because, when a traveling wave is excited in the vibrating body 7, all points of the vibrating body 7 make similar elliptical motions with different timings,
This is because all points of the vibrating body 7 can be brought into contact with the moving body 11 periodically.

Further, in the above-described second embodiment,
The protrusion 15 formed on the surface of the vibrating body 7 is
It is assumed that the projections are provided on the surface of the side not facing the piezoelectric body 6 and opposed to the location marked with “+” or “−” in FIG. The installation position of 15 is not limited to the position described with reference to FIG. The number, shape, and material of the projections 15 are not limited. In short, the protrusion 15 only needs to rotate the moving body 11 in conjunction with the traveling wave excited by the vibration body 7.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
The configuration of the head actuator mechanism according to the embodiment will be described together with the operation with reference to the drawings.

FIG. 11 shows a cross section of a head actuator mechanism according to a third embodiment of the present invention. In the figure,
5 is an elastic body, 6 is a piezoelectric body made of piezoelectric ceramic, 7 is a vibrating body formed by bonding the piezoelectric body 6 to the elastic body 5,
8 is a support, 9 is a friction material, 10 is an elastic body, 11 is a moving body composed of the friction material 9 and the elastic body 10, 12 is a pressure spring, 13
Is a bearing, 14 is a retaining ring, and 15 is a projection formed on the surface of the vibrating body 7. The configuration of the head actuator mechanism according to the third embodiment of the present invention is the same as the configuration of the head actuator mechanism according to the first or second embodiment of the present invention. The operation of the portion affected by the operation is different from that described in the first or second embodiment.

The vibrating body 7 is formed by bonding a disk-shaped piezoelectric ceramic as the piezoelectric body 6 to one of the disk surfaces of a disk-shaped elastic body 5 made of stainless steel or the like. Each of the piezoelectric body 6 and the elastic body 5 is a disk having a hole at the center. Further, the vibrating body 7 has a support 8
Is held by Although not shown, electrodes are provided on both surfaces of the piezoelectric body 6.

A moving body 11 composed of a friction material 9 made of a wear-resistant material and an elastic body 10 made of stainless steel or the like is pressed on the vibrating body 7 by a pressure spring 12 via the friction material 9. Is in pressure contact with the protrusion 15 formed on the substrate.
The pressurizing spring 12 is fixed with a set amount of deflection so that a set pressing force is obtained by the retaining ring 14.
A bearing 13 is provided to transmit the rotary motion to the moving body 11 without any loss.

Next, FIG. 12 illustrates an example of electrodes provided on the surface of the piezoelectric body 6 of the head actuator mechanism shown in FIG. 11 which is not opposed to the elastic body 5 and an example of polarization of the piezoelectric body 6. FIG. The electrodes are arranged in each of the fan-shaped regions 121 to 132 in FIG. In the present embodiment, unlike the second embodiment, the electrodes are
The piezoelectric body 6 is provided with an outer electrodeless portion 50 on which no electrodes are arranged. That is, substantially no voltage is applied to the outer electrodeless portion 50. The symbols “+” and “−” written in each of the regions 121 to 132 have the same meanings as those described with reference to FIGS. That is, the regions 121 to 132 of the piezoelectric body 6 are regions in which the polarization of the “+” region and the polarization of the “−” region are opposite to each other in the thickness direction of the piezoelectric body 6. The figure shows point 1 of the piezoelectric body 6.
An example in which a vibration mode having one node circle in the radial direction (hereinafter, referred to as a first mode) and a third-order elastic wave in the circumferential direction is excited with respect to a circle having substantially the center at 20 is shown. It is a figure which shows the electrode group A shown by the white background in the figure.
And the electrode group B with hatching is 1/4 in the circumferential direction.
They are displaced by an amount corresponding to the wavelength. Although not shown, electrodes are disposed on substantially the entire surface of the piezoelectric body 6 facing the elastic body 5.

The protrusion 15 formed on the surface of the vibrating body 7 is a surface of the elastic body 5 on the side not facing the piezoelectric body 6, and is indicated by "+" or "-" in FIG. It is provided at a position facing the place where the symbol is attached.

When a voltage is applied to the electrode groups A and B of the piezoelectric body 6 of the actuator mechanism configured as described above in the same manner as in the second embodiment, a traveling wave is applied to the vibrating body 7 in the circumferential direction. Is excited. Thus, also in the actuator mechanism of FIG. 11, the magnetic head 3 is moved according to the same operation principle as that of the second embodiment. By the way, in the present actuator mechanism, since the support 8 supports only the central portion of the vibrating body 7, it is possible to excite the zero-order mode. Further, the piezoelectric body 6 constituting the vibrating body 7 has an electrode configuration in which the primary mode is easily excited in the radial direction. In other words, the configuration is such that both the zeroth-order mode and the first-order mode in the radial direction can be excited. This is due to the fact that the vibrating body 7 is supported only at the center and that no electrodes are provided on the outer electrodeless portion 50.

In the actuator mechanisms of the first and second embodiments, in order to improve the driving efficiency, the vibrating body 7 is driven at the resonance frequency of the vibration mode in which the excitation is most easily performed. However, the resonance of the vibration mode that is most easily excited has a large Qm (mechanical quality factor),
There was a phenomenon that the vibrating body 7 was brought into a resonance state due to a harmonic component when the FF was used. As a result, when the drive signal is turned off, a large delay occurs in the response of the moving body 11, which is a great hindrance to achieving high resolution.

Therefore, in this embodiment, two resonance modes can be excited, and among these resonance modes, a vibration mode with a small Qm is used for fine movement, and the other vibration mode is used for coarse movement. It is.

FIG. 13 shows an example of the vibration characteristics of the vibrating body 7 that simultaneously excites two vibration modes. FIG. 3 shows resonance characteristics when a vibrating body 7 is formed by bonding a piezoelectric body 6 having a diameter of 20 mm to an elastic body 5 having a diameter of 25 mm, and a center portion is supported by a support body 8. Here, four resonances are observed. The resonance at the frequency of 14 kHz is the resonance of the 0th-order mode, and the resonance of the frequency of 55.3 kHz is the resonance of the first-order mode. The other two
The two resonances are unnecessary vibrations (unnecessary resonances) for rotating the moving body 11.

With this configuration, it is possible to realize characteristics in which the resolution of the actuator mechanisms of the first and second embodiments is further improved.

When a standing wave is generated in the vibrating body 7,
It is needless to say that the same effect as in the first embodiment can be obtained, and when a traveling wave is generated in the vibrating body 7, the same effect as in the second embodiment can be obtained. That is, the vibrating body 7
Also when the standing wave is excited, the vibrating body 7 is supported only at the central portion, and the electrodes are not arranged on substantially the entire surface of the piezoelectric body 6 as shown in FIG. Higher resolution can be achieved by providing an outer electrodeless portion that is not performed.

Here, a case has been described in which the 0th-order mode is used for fine movement and the first-order mode is used for coarse movement, judging from the magnitude of Qm. By selecting the vibrating body 7, the piezoelectric body 6, and the supporting method thereof appropriately, the same effect can be obtained even if the 0th mode is used for coarse movement and the 1st mode is used for fine movement. It goes without saying that you can do it.

In the third embodiment described above, the electrodes are arranged in the regions 121 to 132 on one surface of the piezoelectric body 6, and the outer electrodeless portion 50 is provided on the surface.
As shown in FIG. 9, a region where the electrodes are not substantially disposed may not be provided on one surface of the piezoelectric body 6, and a region where the electrodes are not disposed may be provided on the outer peripheral portion of the other surface of the piezoelectric body 6. Alternatively, a region where no electrode is provided may be provided on the outer peripheral portions of both surfaces of the piezoelectric body 6. Alternatively, the outer electrodeless portion 50 shown in FIG.
The size of the piezoelectric body 6 may be reduced by the amount of. In short, by appropriately adjusting the arrangement of the electrodes on the piezoelectric body 6, the size of the piezoelectric body 6, and the method of applying a voltage to the piezoelectric body 6, the zero-order mode and the 1st mode can be obtained in the radial direction of the vibrating body 7. It is only necessary to excite two types of modes, or three or more types, of the next mode.

Also, by arranging the balancer in the same manner as in the first embodiment, the same effect as in the first embodiment, that is, the case where the surface of the magnetic recording disk 4 is in the vertical direction can be obtained. Also, it is possible to suppress the rotational moment generated by the support arm 2 and the magnetic head 3 being affected by gravity.

In the third embodiment described above, the case where the waves formed on the vibrating body 7 are the traveling waves of the 0th order and the 1st mode in the radial direction, but the 0th order and the 1st order in the radial direction are described. There is no need to stick to the next mode. Similarly, it is not necessary to stick to three waves in the circumferential direction. In short, the piezoelectric body 6
In this case, it is only necessary to apply a voltage so that two or more types of traveling waves are formed in the circumferential direction of the vibrating body 7.

In the third embodiment described above, the moving body 11 is rotated by the protrusion 15 provided on the vibrating body 7. However, the distance between the vibrating body 7 and the moving body 11 is set to an appropriate distance. In this case, there is no need to provide the projection 15. Because, when a traveling wave is excited in the vibrating body 7, all points of the vibrating body 7 make similar elliptical motions with different timings,
This is because all points of the vibrating body 7 can be brought into contact with the moving body 11 periodically.

Further, in the third embodiment described above,
The protrusion 15 formed on the surface of the vibrating body 7 is
FIG. 12 shows a surface on the side not facing the piezoelectric body 6.
Although it is assumed that the projection 15 is provided at a position facing the place where the symbol “+” or “−” is attached, the installation position of the projection 15 is not limited to the position described with reference to FIG.
The number, shape, and material of the projections 15 are not limited. In short, the protrusion 15 only needs to rotate the moving body 11.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 14 is a block diagram of a driving circuit when the driving method according to the fourth embodiment of the present invention is applied to the actuators according to the first to third embodiments.

In the figure, 1 is a head actuator, 17 is a transmitter, 18 is a 90 ° phase shifter, and 19a and 1
9b is a power amplifier, 20 is a calculator, and 21 is an oscillation controller.

A signal of a reference frequency is generated by a transmitter 17, the reference frequency signal is branched, and one of the signals is input to a 90 ° phase shifter 18. Then, these two signals are input to the power amplifiers 19a and 19b, respectively, amplified to drive voltage, and applied to the two electrodes of the actuator 1. Further, while detecting the signal on the magnetic recording disk with the magnetic head, the error between the current head position and the target position is calculated by the arithmetic unit 2.
The calculation is made to be zero, the difference is fed back to the oscillation controller 21, and the frequency of the oscillator 17 is changed.

FIG. 15 is a schematic diagram of drive signals obtained by applying the drive method of the present embodiment to the actuator mechanisms of the first and second embodiments. Before the point F, coarse movement has been performed. Then, as a result of calculating the information obtained from the magnetic head by the calculator 20, it is found that the target position is approaching, and the drive signal is switched for fine movement. The switching of the frequency is performed by the oscillation controller 21. When the magnetic head reaches the target position, the application of the drive signal is terminated.

FIG. 16 also shows a schematic diagram of the drive signals according to the third embodiment. In the first and second embodiments, the coarse movement frequency is smaller than the fine movement frequency, but in the third embodiment, the only difference is that the coarse movement frequency is larger than the fine movement frequency.

In this configuration, the change between the coarse movement and the fine movement can be realized only by changing the frequency. This driving method is an effective means in a situation where it is difficult to apply a high voltage to the actuator.

Further, since the gain of the amplifier can be reduced, a low-grade amplifier or circuit element can be used, and the effect of reducing the cost of the drive circuit can be exhibited. Further, by further improving the transmission efficiency of the actuator, it becomes possible to drive without an amplifier, and it is possible to expect an effect of further cost reduction.

(Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 17 is a block diagram of a driving circuit when the driving method according to the fifth embodiment of the present invention is applied to the actuators according to the first to third embodiments.

In the figure, 1 is a head actuator, 17 is a transmitter, 18 is a 90-degree phase shifter, 19a and 1
9b is a power amplifier, 20 is a calculator, and 21 is an oscillation controller.

A signal having a reference frequency is generated by a transmitter 17, the reference frequency signal is branched, and one of the signals is input to a 90 ° phase shifter 18. Then, these two signals are input to the power amplifiers 19a and 19b, respectively, amplified to drive voltage, and applied to the two electrodes of the actuator 1. Further, while detecting the signal on the magnetic recording disk with the magnetic head, the error between the current head position and the target position is calculated by the arithmetic unit 2.
The difference is fed back to the oscillation controller 21 and the frequency of the oscillator 17 is varied. Further, the gain of the amplifier is changed based on the difference, and the driving voltage is changed simultaneously with the driving frequency.

FIG. 18 is a schematic diagram of a driving signal obtained by applying the driving method of the present embodiment to the actuator of the third embodiment. Before point H, coarse movement has been performed. Then, the information obtained from the magnetic head is calculated by the arithmetic unit 20.
As a result of the calculation, it can be seen that the target position is approaching, the drive signal is switched for fine movement, and the drive voltage is also changing at the same time. The switching of the frequency is performed by the oscillation controller 21. When the magnetic head reaches the target position, the application of the drive signal is terminated.

In the driving method according to the fourth embodiment, since the head is moved at a constant voltage, it takes a long time to move the head. In the present embodiment, the driving body is changed by changing the driving voltage. To shorten the vibration excitation time,
It is possible to further improve the coarse movement speed,
The time required for driving the head can be significantly reduced, and a head actuator mechanism that moves the head at high speed can be provided.

Note that, as in the fourth embodiment, the first,
It goes without saying that even when the driving method of the present embodiment is applied to the second embodiment, the same effect is obtained only by changing the frequency relationship between the fine movement and the coarse movement.

As described above, it is possible to provide a high-performance actuator mechanism that excites flexural vibration on the vibrating body 7 and transmits the vibration to the moving body 11 and achieves both fine movement and coarse movement. In addition, it is possible to realize higher density and lower cost of the magnetic recording disk device.

[0086]

As is apparent from the above description, the present invention can provide a head actuator mechanism that performs both coarse and fine movements of the head in one.

[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 head actuator mechanism according to the first embodiment of the present invention.

FIG. 3 is a view for explaining an example of electrodes provided on a surface of the piezoelectric element 6 of the head actuator mechanism according to the first embodiment of the present invention which is not opposed to the elastic element 5 and polarization of the piezoelectric element 6; Top view of

FIG. 4 is a view for explaining a position where a protrusion 15 formed on the surface of the vibrating body 7 of the head actuator mechanism according to the first embodiment of the present invention is arranged.

FIG. 5 is a view showing a state in which a projection body 15 moves when a standing wave is excited on the vibrating body 7 according to the first embodiment of the present invention.

FIG. 6 is a view different from FIG. 5, showing how the protrusions 15 move when a standing wave is excited on the vibrator 7 in the first embodiment of the present invention.

FIG. 7 is a plan view showing an application structure of the magnetic disk drive according to the first embodiment of FIG. 1;

FIG. 8 is a sectional view of a head actuator mechanism according to a second embodiment of the present invention.

FIG. 9 is a view for explaining an example of electrodes provided on a surface of the piezoelectric element 6 of the head actuator mechanism according to the second embodiment of the present invention which is not opposed to the elastic element 5 and polarization of the piezoelectric element 6; Top view of

FIG. 10 illustrates a vibrating body 7 according to a second embodiment of the present invention.
The figure which shows a mode that the moving body 11 is driven via frictional force by the traveling wave excited above, and moves.

FIG. 11 is a sectional view of a head actuator mechanism according to a third embodiment of the present invention.

FIG. 12 is a view for explaining an example of electrodes provided on a surface of the piezoelectric body 6 of the head actuator mechanism according to the third embodiment of the present invention which is not opposed to the elastic body 5 and polarization of the piezoelectric body 6; Top view of

FIG. 13 is a diagram illustrating an example of a vibration characteristic of the vibrating body 7 of the head actuator mechanism according to the third embodiment of the present invention.

FIG. 14 is a drive circuit block diagram for explaining a drive method according to a fourth embodiment of the present invention.

FIG. 15 is a schematic diagram of a driving signal in which the driving method according to the fourth embodiment is applied to the actuator mechanisms according to the first and second embodiments;

FIG. 16 is a schematic diagram of a drive signal obtained by applying the drive method according to the fourth embodiment to the actuator mechanism according to the third embodiment;

FIG. 17 is a drive circuit block diagram for explaining a drive method according to a fifth embodiment of the present invention.

FIG. 18 is a schematic diagram of a drive signal obtained by applying the drive method according to the fifth embodiment to the actuator mechanism according to the third embodiment;

FIG. 19 is a plan view of a conventional head actuator including a second actuator for fine movement.

FIG. 20 is an enlarged view of the second actuator for fine movement of FIG. 19;

DESCRIPTION OF SYMBOLS 1 Head actuator 2 Support arm including suspension 3 Magnetic head 4 Magnetic recording disk 5 Elastic body 6 Piezoelectric body 7 Vibrating body 8 Support body 9 Friction material 10 Elastic body 11 Moving body 12 Pressure spring 13 Bearing 14 Stop Wheel 15 Protrusion 16 Balancer 17 Transmitter 18 90-degree phase shifter 19a, 19b Power amplifier 20 Operation unit 21 Oscillation controller

Continuation of the front page (72) Inventor Kawa-Saki ▼ Osamu 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5D096 NN03

Claims (6)

[Claims] 1. A piezoelectric substrate to which a predetermined voltage is applied, a moving body interlocked with the movement of one surface of the piezoelectric substrate, an arm member connected to the moving body, and a movable member provided on the arm member. The moving body rotates in a plane substantially perpendicular to the vibration direction of the piezoelectric substrate due to the application of the voltage, and the head moves in a rotational movement plane of the moving body, or A head actuator mechanism that moves in a plane substantially parallel to the rotational movement plane. 2. The piezoelectric device according to claim 1, further comprising: a protrusion connected to the one surface of the piezoelectric substrate, wherein the movable body is interlocked with the movement of the protrusion, and the piezoelectric substrate has a predetermined position within a surface of the piezoelectric substrate. 2. The head actuator mechanism according to claim 1, wherein a voltage is applied so that a predetermined standing wave is formed in a circumferential direction having the point substantially at the center. 3. A voltage is applied to the piezoelectric substrate such that a predetermined traveling wave is formed in a circumferential direction substantially at a predetermined point in the surface of the piezoelectric substrate. The head actuator mechanism according to claim 1, wherein 4. A voltage is applied to the piezoelectric substrate such that two or more vibration waves having different frequencies are formed in a radial direction of a circumference having the substantially center. 4. The head actuator mechanism according to 2 or 3. 5. The voltage applied to the piezoelectric substrate is an AC voltage, and the frequency and / or amplitude of the AC voltage changes with the passage of time. 3. The head actuator mechanism according to 1. 6. The head according to claim 1, further comprising a balancer installed vertically above a position where the piezoelectric substrate is installed, the balancer suppressing a rotational moment generated by the head being affected by gravity. 6. The head actuator mechanism according to any one of 1 to 5.