JP2010067311A - Information recording and reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording and reproducing apparatus which can precisely regulate the distance between a slider and a magnetic recording medium while suppressing the power consumption. <P>SOLUTION: This information recording and reproducing apparatus includes a swing arm 11 supporting the slider 2, and a pivot shaft 10 rotatably supporting the swing arm 11. The pivot shaft 10 has a shaft 41 erected on the housing 9, and a piezoelectric actuator 60 is disposed between the housing 9 and the flange 44 formed on the shaft 41 and around the small diameter section 48 of the shaft 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an information recording / reproducing apparatus.

  2. Description of the Related Art Conventionally, an information recording / reproducing apparatus such as a hard disk for storing and reproducing various kinds of information on a disk (magnetic recording medium) is known. Generally, an information recording / reproducing apparatus includes a swing arm provided with a slider for recording / reproducing a signal on / from a disk. The swing arm is rotatable by a bearing device provided on the base end side. By rotating the swing arm along the horizontal plane, the slider at the tip is moved to a predetermined position on the magnetic recording medium, so that signal recording and reproduction can be performed.

Generally, in order to increase the recording density of an information recording / reproducing apparatus, it is necessary to reduce the distance between the slider and the disk. However, in the conventional information recording / reproducing apparatus, even if the surface of the disk has waviness or the like, the flying height of the slider is provided so that the slider does not contact the disk. Therefore, it is difficult to reduce the distance between the slider and the disk.
Therefore, in Patent Document 1 and Non-Patent Document 1, a heater made of a thin film resistor is provided between the slider substrate and the reproducing element, and a part of the thin film head portion is heated as necessary to thermally expand and protrude, A slider structure that adjusts the distance between the reproducing element and the recording element and the magnetic recording medium has been proposed.
JP 2007-287277 A Kurita, "Nanotribology for high recording density hard disks-Active control of nano-sliding clearance", Tribologist, Japan Society of Tribology, 2008, Vol. 53, No. 6, p. 375-380

However, the above-described technique has a problem that power consumption is large because current flows through the heater. In addition, there is a problem that the responsiveness between the heat generation of the heater and the thermal expansion of the thin film head is poor, and the portion that should not be thermally expanded due to the heat generation of the heater is also thermally expanded.
The present invention has been made in view of the above problems, and provides an information recording / reproducing apparatus capable of accurately controlling the distance between a slider and a magnetic recording medium while suppressing power consumption. For the purpose.

In order to solve the above problems, an information recording / reproducing apparatus of the present invention is configured so that a rotatable magnetic recording medium, a slider for recording / reproducing information on the magnetic recording medium, and the magnetic recording medium are opposed to each other. A swing arm that supports the slider, and a bearing device that rotatably supports the swing arm, and an actuator that moves the swing arm so that a distance between the slider and the magnetic recording medium changes, Is further provided.
According to the present invention, it is possible to adjust the distance between the slider and the magnetic recording medium without using a heater, and power consumption can be suppressed. Further, it is possible to prevent thermal expansion of each part of the slider, and it is possible to prevent variation in the flying height of the slider. Therefore, the distance between the slider and the magnetic recording medium can be accurately controlled.

A sensor for detecting a surface state of the magnetic recording medium; and a controller for driving the actuator based on a detection result of the sensor and adjusting a distance between the slider and the magnetic recording medium. Is desirable.
In this case, the slider can be moved following the undulation of the surface state of the magnetic recording medium, and the distance between the slider and the magnetic recording medium can be kept constant. Therefore, it is not necessary to provide a margin for the flying height of the slider, and the distance between the slider and the magnetic recording medium can be reduced. Therefore, the information recording / reproducing apparatus can be increased in recording density.

The actuator is preferably a piezoelectric actuator provided with a piezoelectric element.
Piezoelectric actuators have excellent responsiveness to drive signals and have little variation in expansion and contraction. Therefore, the distance between the slider and the magnetic recording medium can be accurately controlled. In addition, since the piezoelectric actuator has low power consumption and does not generate magnetism, it does not affect the slider or the magnetic recording medium.

The bearing device may include a shaft standing on a housing, and the actuator may be disposed between the housing and a flange formed on the shaft and around the shaft.
In this case, the slider can be moved in the vertical direction together with the bearing member and the swing arm by the expansion and contraction of the shaft.

Moreover, it is desirable that a groove is formed in the housing or the flange along the outer periphery of the shaft.
In this case, since the shaft that is deformed and stretched becomes longer, the rigidity of the shaft becomes smaller. Therefore, the shaft can be stretched and deformed without generating a large stretching force by the actuator. Therefore, the power consumption of the actuator can be reduced.

The actuator preferably includes a pair of piezoelectric elements sandwiched between the housing and the flange, and a common electrode sandwiched between the pair of piezoelectric elements.
In this case, since the housing and the flange are connected to the frame ground, a pair of piezoelectric elements can be driven simultaneously by applying a voltage to the common electrode.

  According to the information recording / reproducing apparatus of the present invention, the distance between the slider and the magnetic recording medium can be accurately controlled while suppressing power consumption. Further, the distance between the slider and the magnetic recording medium can be reduced, and the information recording / reproducing apparatus can be increased in recording density.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a perspective view of an information recording / reproducing apparatus according to an embodiment. Note that the information recording / reproducing apparatus 1 of the present embodiment is an apparatus for writing on a disk (magnetic recording medium) D having a perpendicular recording layer by a perpendicular recording method.

  As shown in FIG. 1, the information recording / reproducing apparatus 1 includes a swing arm 11, a head gimbal assembly (HGA) 12 supported on the tip side of the swing arm 11, and a head gimbal assembly 12 on a disk surface D1 (disc D An actuator 6 that scans and moves in a horizontal plane direction parallel to the surface), a spindle motor 7 that rotates the disk D about the rotation axis L2, and a current modulated according to information to the slider 2 of the head gimbal assembly 12 The control part 5 to supply and the housing 9 which accommodates each of these components inside are provided.

  The housing 9 is made of a metal material such as aluminum and has a box-like shape having an upper opening. The housing 9 has a quadrangular bottom portion 9a as viewed from above, and stands vertically with respect to the bottom portion 9a at the periphery of the bottom portion 9a. And a peripheral wall (not shown). And the recessed part which accommodates each component mentioned above is formed in the inner side enclosed by the surrounding wall. In FIG. 1, the peripheral wall surrounding the housing 9 is omitted for easy understanding.

  In addition, a lid (not shown) is detachably fixed to the housing 9 so as to close the upper opening. The spindle motor 7 is attached to substantially the center of the bottom portion 9a, and the disc D is detachably fixed by fitting a center hole into the spindle motor 7.

  The actuator 6 described above is attached to one corner of the bottom 9a outside the disk D. A swing arm 11 is attached to the actuator 6 so as to be rotatable about a rotation axis L1 in a horizontal plane with a pivot shaft (bearing device) 10 as a center. In the swing arm 11, an arm portion 14 extending in the direction of the disk D and a base portion 15 that supports the arm portion 14 in a cantilever shape are integrally formed by cutting or the like. The base portion 15 is formed in a substantially rectangular parallelepiped shape, and is supported so as to be rotatable around the pivot shaft 10. That is, the base portion 15 is connected to the actuator 6 via the pivot shaft 10, and the pivot shaft 10 is the center of rotation of the swing arm 11.

  The arm portion 14 extends in parallel with the surface direction (horizontal plane direction) of the upper surface of the base portion 15 on the side surface 15b opposite to the side surface 15a to which the actuator 6 is attached in the base portion 15 (side surface on the opposite side of the corner portion). It is a flat plate to be extended, and three pieces are extended along the height direction (vertical direction) of the base 15. Specifically, the arm portion 14 is formed in a tapered shape that tapers from the proximal end portion toward the distal end portion, and is arranged so that the disk D is sandwiched between the arm portions 14 and 14. That is, the arm portions 14 and the disks D are alternately arranged, and the arm portions 14 can be moved in a direction parallel to the surface of the disk D (horizontal plane direction) by driving the actuator 6. The swing arm 11 is retracted from the disk D by driving the actuator 6 when the rotation of the disk D is stopped.

  The head gimbal assembly 12 is connected to the tip of the arm portion 14 and includes a suspension 3 and a slider 2 attached to the tip of the suspension 3. The slider 2 is provided with a recording element for writing (recording) information on the disk D and a reproducing element for reading (reproducing) information from the disk D.

  FIG. 2 is an explanatory diagram of the information recording / reproducing apparatus of the first embodiment, and is a cross-sectional view taken along the line AA of FIG. As shown in FIG. 2, the pivot shaft 10 includes a shaft 41 and a sleeve 43 that are arranged coaxially. The sleeve 43 is press-fitted or adhesively fitted to the swing arm 11, and the shaft 41 is erected on the housing 9. A piezoelectric actuator 60 including a piezoelectric element is provided between the housing 9 and the flange 44 of the shaft 41 and around the shaft 41.

  FIG. 3 is a cross-sectional view of the pivot shaft and the piezoelectric actuator. The pivot shaft 10 includes a shaft 41 formed in a substantially columnar shape, a substantially cylindrical sleeve 43 that is spaced apart from the outer peripheral surface 41 a of the shaft 41 by a predetermined distance, and the shaft 41 and the sleeve 43. A first rolling bearing 51 interposed; and a second rolling bearing 52 interposed between the shaft 41 and the sleeve 43 in parallel with the first rolling bearing 51 at a predetermined interval. Yes.

  The sleeve 43 is a member formed in a substantially cylindrical shape, and the first rolling bearing 51 is mounted on one end side in the longitudinal direction (axial direction) and the second rolling bearing 52 is mounted on the other end side. In addition, while the first rolling bearing 51 and the second rolling bearing 52 in the sleeve 43 are arranged, the spacer portion 45 that holds the distance between the first rolling bearing 51 and the second rolling bearing 52 at a predetermined distance is used. It protrudes inward in the direction. The sleeve 43 and the spacer portion 45 may be formed of separate members.

  The shaft 41 is a substantially cylindrical rod-like member, and a first rolling bearing 51 is attached to one end side in the longitudinal direction (axial direction), and the second rolling bearing is spaced apart from the first rolling bearing 51 in the axial direction. 52 is attached. On one end side of the shaft 41, a flange 44 that is larger in diameter than the shaft 41 and is in contact with the first rolling bearing 51 is formed. A small-diameter portion 48 that is smaller in diameter than the shaft 41 is provided upright at the central portion on one end side of the shaft 41. A male screw is formed at the tip of the small diameter portion 48 and is screwed with a female screw formed in the housing 9. Note that pre-compression is applied in the thickness direction of the piezoelectric actuator 60. A groove portion 46 is formed in the flange 44 on one end side of the shaft 41 along the outer periphery of the small diameter portion 48 of the shaft 41.

  The piezoelectric actuator 60 is provided between the housing 9 and the flange 44 and around the small diameter portion 48 of the shaft 41. The piezoelectric actuator 60 includes a pair of piezoelectric elements 61 and 62 sandwiched between the housing 9 and the flange 44, and a common electrode 64 sandwiched between the pair of piezoelectric elements 61 and 62. The pair of piezoelectric elements 61 and 62 are formed in a ring shape from a piezoelectric material such as quartz, PZT, or barium titanate, and are polarized in opposite directions in the thickness (L1) direction as indicated by arrows. The common electrode 64 is formed in a ring shape from a conductive metal material such as a copper plate. A first electrode 61 a is formed on the side surface opposite to the common electrode 64 in the first piezoelectric element 61, and a second electrode 62 a is formed on the side surface opposite to the common electrode 64 in the second piezoelectric element 62.

The first electrode 61 a is connected to the flange 44, and the second electrode 62 a is connected to the housing 9. Since the first electrode 61a is connected to the housing 9 via the flange 44 and the small diameter portion 48, both the first electrode 61a and the second electrode 62a are connected to the frame ground. On the other hand, the common electrode 64 is connected to a DC power source.
When a DC voltage is applied to the common electrode 64, a voltage can be applied simultaneously in the thickness direction of the pair of piezoelectric elements 61 and 62. Accordingly, the pair of piezoelectric elements 61 and 62 can be expanded and contracted in the thickness direction.

FIG. 4 is a cross-sectional view of a modification of the piezoelectric actuator. The piezoelectric actuator 160 includes one piezoelectric element 61 between the housing 9 and the flange 44. Electrodes 61 a and 61 b are formed on both surfaces of the piezoelectric element 61 in the thickness direction. The lower electrode 61a is connected to the frame ground, and the upper electrode 61b is connected to a DC power source. In addition, when the upper electrode 61b contacts the flange 44, it will short-circuit with the lower electrode 61a. Therefore, an insulating sheet 63 is disposed between the upper electrode 61 b and the flange 44.
In the piezoelectric actuator 160, the piezoelectric element 61 can be expanded and contracted in the thickness direction by applying a DC voltage to the upper electrode 61b.

  Returning to FIG. 3, when the piezoelectric actuator 60 expands and contracts in the thickness direction, the small diameter portion 48 of the shaft 41 that penetrates the central portion of the piezoelectric actuator 60 expands and contracts, and the upper side of the flange 44 of the pivot shaft 10 extends in the vertical direction. Moving. In addition, since the length of the small diameter part 48 is extended by forming the groove part 46 around the small diameter part 48, the rigidity of the small diameter part 48 is low. Therefore, the small diameter portion 48 can be expanded and deformed without generating a large expansion and contraction force with the piezoelectric actuator 60. Therefore, the power consumption of the piezoelectric actuator 60 can be reduced. The groove 46 around the small diameter portion 48 may be formed in the housing 9, or may be formed in both the flange 44 and the housing 9.

Returning to FIG. 2, when the pivot shaft 10 moves in the vertical direction, the swing arm 11 fixed to the sleeve 43 moves in the vertical direction. As a result, the slider 2 supported at the tip of the swing arm 11 moves in the vertical direction, and the distance between the slider 2 and the disk D can be adjusted.
In this embodiment, the distance between the slider 2 and the disk D can be adjusted without using a heater, and power consumption can be suppressed. Further, it is possible to prevent thermal expansion of each part of the slider, and it is possible to prevent variation in the flying height of the slider 2. Therefore, the distance between the slider 2 and the disk D can be accurately controlled.

  Incidentally, the surface of the disk D has waviness in the circumferential direction. This undulation changes the distance between the slider 2 and the disk D. Therefore, the information recording / reproducing apparatus of the present embodiment includes a sensor that detects the surface state of the magnetic recording medium, and a controller that drives the piezoelectric actuator 60 based on the detection result of the sensor and adjusts the distance between the disk D and the slider 2. 5 (see FIG. 1). The sensor measures the undulation of the disk D by magnetic signal modulation or the like. Further, the control unit extracts a low frequency component corresponding to the undulation of the disk D from the detection result of the sensor, and drives the piezoelectric actuator 60 so that the slider 2 moves in the vertical direction following the low frequency component. As a result, the distance between the disk D and the slider 2 can be kept constant.

  Generally, in order to increase the recording density of the information recording / reproducing apparatus, it is necessary to reduce the distance between the slider 2 and the disk D. However, in the conventional information recording / reproducing apparatus, the flying height of the slider 2 is given a margin so that the slider 2 does not come into contact with the disk D even when the disk D is wavy. Therefore, it is difficult to reduce the distance between the slider 2 and the disk D.

  On the other hand, in this embodiment, the piezoelectric actuator 60 that moves the swing arm 11, a sensor that detects the surface state of the disk, the actuator is driven based on the detection result of the sensor, and the disk D and the slider 2 And a control unit for adjusting the distance. According to this configuration, the slider 2 can be moved following the undulation of the disk D, and the distance between the disk D and the slider 2 can be kept constant. Therefore, it is not necessary to provide a margin for the flying height of the slider 2, and the distance between the slider 2 and the disk D can be reduced. Therefore, the information recording / reproducing apparatus can be increased in recording density.

(Second Embodiment)
FIG. 5 is an explanatory diagram of the information recording / reproducing apparatus of the second embodiment, and is a cross-sectional view of a portion corresponding to the line AA of FIG. The second embodiment shown in FIG. 5 differs from the first embodiment in that a piezoelectric actuator 260 is disposed between the flange 47 of the sleeve 43 of the pivot shaft 10 and the swing arm 11. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.
A flange 47 is formed at the upper end of the sleeve 43 of the pivot shaft 10. A piezoelectric actuator 260 is disposed between the flange 47 and the swing arm 11.

FIG. 6 is an enlarged view of a portion P in FIG. A piezoelectric actuator 260 shown in FIG. 6 includes a ring-shaped piezoelectric element 61 between the flange 47 and the swing arm 11. Electrodes 61 a and 61 b are formed on both surfaces of the piezoelectric element 61 in the thickness direction. The lower electrode 61a is connected to the frame ground, and the upper electrode 61b is connected to a DC power source. In addition, when the upper electrode 61b contacts the flange 47, it short-circuits with the lower electrode 61a. Therefore, an insulating sheet 63 is disposed between the upper electrode 61 b and the flange 47.
In the piezoelectric actuator 260, the piezoelectric element 61 can be expanded and contracted in the thickness direction by applying a DC voltage to the upper electrode 61b.

  Returning to FIG. 5, when the piezoelectric actuator 260 expands and contracts in the thickness direction, the swing arm 11 is bent and deformed as indicated by a two-dot chain line 90 in FIG. 5. A groove portion 49 is formed around the sleeve 43. Thereby, the bending rigidity of the swing arm 11 is small. Therefore, the swing arm 11 can be bent and deformed without generating a large expansion / contraction force with the piezoelectric actuator 260. Therefore, the power consumption of the piezoelectric actuator 260 can be reduced. When the swing arm 11 is bent and deformed, the slider 2 supported at the tip of the swing arm 11 moves in the vertical direction, and the distance between the slider 2 and the disk D can be adjusted.

  In the second embodiment, as in the first embodiment, the distance between the slider 2 and the disk D can be accurately controlled while suppressing power consumption. Further, the distance between the slider 2 and the disk D can be reduced, and the information recording / reproducing apparatus can be increased in recording density.

(Third embodiment)
FIG. 7 is a cross-sectional view of the pivot shaft and the piezoelectric actuator in the information recording / reproducing apparatus of the third embodiment. The third embodiment is different from the first embodiment in that the shaft 41 is not connected to the housing 9. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

  In the third embodiment, a flange 44 is formed on one end side of the shaft 41 as in the first embodiment. However, unlike the first embodiment, a small-diameter portion is erected at the central portion on one end side of the shaft 41. Not. That is, one end side of the shaft 41 is a flat surface. A piezoelectric actuator 60 is sandwiched between one end side of the shaft 41 and the housing 9.

  The piezoelectric actuator 60 is formed in a disk shape and includes a single piezoelectric element 61. Electrodes 61 a and 61 b are formed on both surfaces of the piezoelectric element 61 in the thickness direction. The lower electrode 61a is connected to the frame ground, and the upper electrode 61b is connected to a DC power source. In 3rd Embodiment, since the shaft 41 and the housing 9 are not connected, the upper electrode 61b and the lower electrode 61a do not short-circuit. Therefore, there is no need to provide an insulating sheet or the like. The upper electrode 61b is fixed to the flange 44 of the shaft 41 by bonding or the like, and the lower electrode 61a is fixed to the housing 9 by bonding or the like.

When the piezoelectric actuator 60 expands and contracts in the thickness direction, the pivot shaft 10 moves in the vertical direction as in the first embodiment. As a result, the swing arm fixed to the sleeve 43 moves in the vertical direction, and the slider supported on the tip of the swing arm moves in the vertical direction, so that the distance between the slider and the disk can be adjusted.
In the third embodiment, as in the first embodiment, the distance between the slider and the disk can be accurately controlled while suppressing power consumption. Further, the distance between the slider and the disk can be reduced, and the information recording / reproducing apparatus can be increased in recording density.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the specific materials and layer configurations described in the embodiments are merely examples, and can be changed as appropriate.
For example, although the piezoelectric actuator is employed in the embodiment, other actuators may be employed.

It is a schematic block diagram of the information recording / reproducing apparatus of embodiment. It is explanatory drawing of the information recording / reproducing apparatus of 1st Embodiment, and is sectional drawing in the AA of FIG. It is sectional drawing of a pivot shaft and a piezoelectric actuator. It is sectional drawing of the modification of a piezoelectric actuator. It is explanatory drawing of the information recording / reproducing apparatus of 2nd Embodiment, and is sectional drawing in the part corresponded to the AA line of FIG. It is an enlarged view of the P section of FIG. It is sectional drawing of the pivot axis | shaft and piezoelectric actuator in the information recording / reproducing apparatus of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS D ... Disk (magnetic recording medium) 1 ... Information recording / reproducing apparatus 2 ... Slider 5 ... Control part 9 ... Housing 10 ... Pivot shaft (bearing apparatus) 11 ... Swing arm 41 ... Shaft 44 ... Flange 46 ... Groove part 48 ... Small diameter part 60 , 160, 260... Piezoelectric actuator 61, 62... Piezoelectric element 64.

Claims (6)

A rotatable magnetic recording medium, a slider that records and reproduces information on the magnetic recording medium, a swing arm that supports the slider so as to face the magnetic recording medium, and a swing arm that rotatably supports the swing arm And a bearing device for
An information recording / reproducing apparatus, further comprising: an actuator that moves the swing arm so that a distance between the slider and the magnetic recording medium changes. A sensor for detecting a surface state of the magnetic recording medium;
The information recording / reproducing apparatus according to claim 1, further comprising a control unit that drives the actuator based on a detection result of the sensor and adjusts a distance between the slider and the magnetic recording medium.   The information recording / reproducing apparatus according to claim 1, wherein the actuator is a piezoelectric actuator including a piezoelectric element. The bearing device includes a shaft erected on the housing,
4. The actuator according to claim 1, wherein the actuator is disposed between the housing and a flange formed on the shaft and around the shaft. 5. Information recording / reproducing apparatus.   5. The information recording / reproducing apparatus according to claim 4, wherein a groove is formed in the housing or the flange along the outer periphery of the shaft.   6. The actuator according to claim 4, wherein the actuator includes a pair of piezoelectric elements sandwiched between the housing and the flange, and a common electrode sandwiched between the pair of piezoelectric elements. The information recording / reproducing apparatus described in 1.

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