JP4451980B2 - Head clamp device for disk characteristic evaluation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a head clamp device for a disk characteristic evaluation apparatus in a disk characteristic evaluation apparatus that measures electromagnetic conversion characteristics of a magnetic disk and a magnetic head, which are key components of a hard disk apparatus. More specifically, the present invention relates to a head clamp device used in a test apparatus that positions a magnetic head at a predetermined track position on a magnetic disk and measures recording / reproduction characteristics.
[0002]
[Prior art]
With the recent improvement in characteristics of hard disk drives, it is necessary to improve the performance of evaluation devices that measure the electromagnetic conversion characteristics of magnetic disks and magnetic heads that are key components.
[0003]
In particular, as the track density increases, the core width of the magnetic head tends to become narrower. Therefore, in order to perform accurate measurements, it is essential to improve the track positioning accuracy of the evaluation device itself. Alternatively, the positioning accuracy of the magnetic head is improved by combining a fine movement stage using a piezo element on a coarse movement stage driven by an ultrasonic motor or the like.
[0004]
For example, as a conventional example of this kind of disk characteristic evaluation apparatus, there is a conventional disk characteristic evaluation apparatus 101 as shown in FIGS.
[0005]
Referring to FIG. 8, a conventional disk characteristic evaluation apparatus 101 has a surface plate-like base 103 placed on the upper surface of a control apparatus (not shown) for controlling the drive system of the apparatus. A spindle motor housing 107 having a spindle motor 105 is provided on the upper surface of the base 103, and a disk clamp 109 that is rotationally driven by the spindle motor 105 is provided above the spindle motor housing 107. The magnetic disk 111 is configured to be clamped / unclamped at the upper end of 109.
[0006]
Further, on the upper surface of the base 103, coarse movement for positioning the magnetic heads 113 and 115 in the X-axis direction (left and right direction in FIG. 8) at a position adjacent to the upper side in FIG. A stage 117 (X stage) is provided, and this coarse movement stage 117 is driven in the X-axis direction via a ball screw (not shown) by an ultrasonic motor 119 for driving the X stage.
[0007]
Further, a segment gear 121 is provided on the upper surface of the coarse movement stage 117 and is fixed in a smooth manner in parallel with the magnetic disk 111. The segment gear 121 is formed in a semicircular arc shape and a rack 123 is provided on the outer peripheral edge. It has been. The head loader 127 is provided with a pinion (not shown) driven by a drive motor (not shown) so as to mesh with the rack 123.
[0008]
Further, a head loader 127 provided with a head clamp 125 having a pair of magnetic heads 113 and 115 consisting of a down face and an up face is provided on the segment gear 121 so as to be movable in a semicircular arc shape. 8, the positions of the magnetic heads 113 and 115 and the position of the rotation center of the magnetic disk 111 are on the same line in the X-axis direction.
[0009]
Referring to FIGS. 9 and 10 together, a piezo actuator 129 is provided on the base side of the head loader 127 for finely moving the upper portion of the head loader 127 in the X-axis direction.
[0010]
The head clamp 125 includes an upper head clamp 131 and a lower head clamp 133. The upper head clamp 131 is provided so as to be movable up and down via an upper mounting base 135. The lower head clamp 133 is a lower mounting base. It can be moved up and down via 137. Moreover, the upper head clamp 131 and the lower head clamp 133 are detachably attached to the upper mounting base 135 and the lower mounting base 137. A suspension 141 having a magnetic head 113 (down face) at the tip is clamped to the front end of the upper head clamp 131 via a clamp portion 139, and the front end of the lower head clamp 133 is clamped to the front end of the upper head clamp 131 via a clamp portion 143. A suspension 145 having a magnetic head 115 (up face) at its tip is clamped. A lead wire 147 is connected to each of the suspensions 141 and 145.
[0011]
The head loader 127 includes a vertical movement device for the head clamp 125. The upper and lower head clamps 131 and 133 are independently controlled in the vertical movement, and the magnetic heads 113 and 115 move the magnetic disk 111 in the vertical direction. It is possible to move forward and backward so as to be sandwiched between.
[0012]
In the conventional disk characteristic evaluation apparatus 101 as described above, when evaluating the characteristics of the magnetic heads 113 and 115, after the magnetic disk 111 is set to a predetermined rotational speed by the spindle motor 105, the coarse movement stage 117 is, for example, The magnetic heads 113 and 115 are positioned at predetermined positions by being sent in the X-axis direction in the track width direction.
[0013]
Furthermore, as shown in FIG. 11, after the skew angle α, which is an offset angle with respect to the tangent in the track direction, is set, the head loader is set so that the magnetic heads 113 and 115 at the tip of the HGA have a predetermined flying height. 127 to load. That is, the upper head clamp 131 and the lower head clamp 133 are adjusted in the vertical direction.
[0014]
Next, in the track profile characteristic evaluation and the error rate characteristic evaluation (bathtub characteristic) in which characteristic evaluation is performed while finely moving the track positions of the magnetic heads 113 and 115 in the track width direction, the magnetic heads 113 and 115 are performed by the piezo actuator 129. The positioning resolution of the magnetic heads 113 and 115 is improved by measuring while offset by a minute amount.
[0015]
[Problems to be solved by the invention]
By the way, in the conventional disk characteristic evaluation apparatus 101, after the magnetic heads 113 and 115 are once positioned, the magnetic heads 113 and 115 are mechanically fixed. And the core positions of the magnetic heads 113 and 115 are relatively shifted, and the reproduction output decreases or the previous data becomes difficult to be completely erased. It has become necessary to make the track positions of the heads 113 and 115 follow the recording track.
[0016]
In the conventional experimental apparatus, since a large mass device including the head loader 127 is driven by the piezo actuator 129, it cannot be driven at a high frequency, so that it is impossible to follow the recording track as described above. There was a problem that it was possible.
[0017]
The present invention has been made to solve the above-described problems, and the object thereof is to enable the piezo actuator to be driven at a high frequency so that the track position of the magnetic head can easily follow the recording track at high speed. Another object of the present invention is to provide a head clamp device for a disk characteristic evaluation apparatus.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, a head clamp device for a disk characteristic evaluation apparatus according to a first aspect of the present invention provides an electromagnetic conversion of at least one of a magnetic disk and a magnetic head while rotating a magnetic disk having a plurality of concentric tracks. In a head clamp device for a disk characteristic evaluation apparatus having a head clamp for positioning a magnetic head at a predetermined track position for evaluating characteristics, the head clamp is provided with a microactuator stage that is movable in the left-right direction by a microactuator. the microactuator stage Ri name by attaching a magnetic head, the microactuator stage, a base portion attached to the head clamp, and a stage portion for mounting a magnetic head through the head attaching member, the base and the stage portion A parallel leaf spring shape composed of two parallel elastic pieces to be connected is formed, and a support portion is provided between the two elastic pieces so as to project from the base portion toward the front stage portion. A microactuator is provided between one elastic piece of the two elastic pieces.
[0019]
Therefore, when the microactuator is energized, the piezo microactuator stage slightly moves in the left-right direction in proportion to the input voltage. Along with this, the magnetic head attached to the microactuator stage is finely adjusted in the horizontal direction. Since the rigidity of the entire microactuator stage is improved by reducing the size of the microactuator stage and reducing the weight of the drive portion, the microactuator can be driven by the microactuator.
[0021]
Further, when the microactuator is energized, the elastic piece facing the support portion is pushed or loosened by the microactuator, so that the microactuator stage has a parallel leaf spring shape, so that the two elastic pieces are deformed. Then, the stage part positioned in the forward direction from the base part side slightly moves in the left-right direction. The fine movement stroke of the stage portion is enlarged by a mechanical ratio of the distance from the base portion to the stage portion with respect to the distance from the base portion to the microactuator.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a head clamp device for a disk characteristic evaluation apparatus according to the present invention will be described below with reference to the drawings.
[0025]
Referring to FIGS. 5, 6, and 7, the disk characteristic evaluation apparatus 1 according to the present embodiment is provided with a control device 3 that controls the drive system of the device. A board-shaped base 5 is placed. A spindle motor housing 9 having a spindle motor 7 is provided on the upper surface of the base 5, and a disk clamp 11 that is rotationally driven by the spindle motor 7 is provided on the top of the spindle motor housing 9. 11, the magnetic disk 13 is clamped and unclamped at the upper end portion in FIG.
[0026]
Further, on the upper surface of the base 5, a coarse movement stage 19 (X stage) for positioning the magnetic heads 15, 17 in the X-axis direction is positioned adjacent to the disk clamp 11 in FIG. The coarse movement stage 19 is driven in the X-axis direction (left-right direction in FIGS. 5 and 6) via a ball screw (not shown) by an ultrasonic motor 21 for driving the X-stage.
[0027]
Further, a segment gear 23 is provided on the upper surface of the coarse moving stage 19 and is fixed in a smooth manner in parallel with the magnetic disk 13. The segment gear 23 is formed in a semicircular arc shape and a rack 25 is provided on the outer peripheral edge. It has been.
[0028]
A head loader 29 provided with a head clamp device 27 having a pair of magnetic heads 15 and 17 composed of a down face and an up face is provided on the segment gear 23 so as to be movable in a semicircular arc shape. The head loader 29 is provided with a pinion 31 that meshes with the rack 25 of the segment gear 23. The pinion 31 is rotated and transmitted through a speed reducer (not shown) by a skew angle motor 33 provided in the head loader 29, meshes with the rack 25 of the segment gear 23, and has a rotation angle along its outer peripheral surface. By performing the rotational movement of 90 °, the head loader 29 rotates and the magnetic heads 15 and 17 are positioned. In FIG. 5, the positions of the magnetic heads 15 and 17 and the position of the rotation center of the magnetic disk 13 are positioned on the same line in the X-axis direction.
[0029]
Referring to FIG. 4, the head loader 29 is provided with a head clamp device 27 having a pair of magnetic heads 15 and 17 having a down face and an up face.
[0030]
The head loader 29 is not provided with a conventional microactuator made of a piezo element on the base side, and the microactuator such as a piezo element is provided in another component. ing.
[0031]
The head clamp device 27 includes an upper head clamp 35 and a lower head clamp 37. The upper head clamp 35 is provided so as to be movable up and down via an upper mounting base 39. The lower head clamp 37 is used for lower mounting. The base 41 is provided so as to be movable up and down. The upper head clamp 35 is detachably mounted on the upper mounting base 39 by a dovetail groove 43, and the lower head clamp 37 is also detachably mounted on the lower mounting base 41 by a dovetail groove 43.
[0032]
A suspension 47 having a magnetic head 15 (down face) at the tip is attached to the front end of the upper head clamp 35 via a head attachment member 45, and a head attachment member 49 is attached to the front end of the lower head clamp 37. A suspension 51 having a magnetic head 17 (up face) at the tip is attached. A lead wire 53 (see FIG. 1) is connected to each suspension 47, 51.
[0033]
The head loader 29 has built-in vertical movement devices for an upper head clamp 35 and a lower head clamp 37, and the upper and lower head clamps 35 and 37 are independently controlled to move up and down. Is capable of moving forward and backward at high speed so as to sandwich the magnetic disk 13 from above and below.
[0034]
The head clamp device 27 constituting the main part of the embodiment of the present invention will be described in detail. Since the upper and lower head clamps 35 and 37 have a substantially symmetrical structure and are structurally similar, the upper head clamp 35 will be described in detail, and the description of the lower head clamp 37 will be omitted.
[0035]
Referring to FIG. 1, in FIG. 1, the upper head clamp 35 of FIG. 4 is inverted and shown in a perspective view. A front stage of the upper head clamp 35 is, for example, a piezo stage 55 as a microactuator stage. The base portion 57 is attached by a bolt BT, and a head attachment member 45 is provided on a stage portion 59 on the front end side of the piezo stage 55. A suspension 47 is attached to the head attachment member 45 via a leaf spring (not shown) with a screw 61, and a magnetic head 15 (down face) is provided at the tip of the suspension 47.
[0036]
2 and 3, the piezo stage 55 has a parallel leaf spring shape in which a base portion 57 and a stage portion 59 are integrally connected by two elastic pieces 63 and 65 having elasticity. The two elastic pieces 63 and 65 are respectively provided with constricted portions 67 and 69 for generating elasticity on the base side and the stage side. FIG. 3 shows the planar shape of the piezo stage 55 when the upper head clamp 35 of FIG. 4 is viewed from above (when the upper head clamp 35 of FIG. 2 is viewed from below).
[0037]
Further, a support portion 71 projecting forward from the base portion 57 is provided on the right side of the space between the two elastic pieces 63 and 65 in FIG. 2, while the left elastic piece 63 in FIG. A piezo element receiving portion 73 as a microactuator receiving portion is provided so as to face the support portion 71. A constricted portion 75 is provided between the piezo element receiving portion 73 and the elastic piece 63 to give the piezo element receiving portion 73 flexibility. A piezo actuator 77 as a microactuator is provided between the support portion 71 and the piezo element receiving portion 73.
[0038]
The piezo stage 55 is made of a conductive ceramic, metal, or the like as a material, and is manufactured by precisely processing this material by wire electric discharge machining or the like. Among the conductive ceramics described above, sialon has excellent characteristics such as high-temperature strength characteristics, molten metal corrosion resistance, and wear resistance. Since sialon is a difficult-to-process material, near-net molding and sintering techniques are indispensable, but conductive sialon material HCN-40 (trade name) can be precisely machined by wire electric discharge machining.
[0039]
The conductive sialon material HCN-40 has an electric resistivity as low as 7 × 10 −40 Ω · cm, and therefore can be subjected to electric discharge machining at a higher speed than cemented carbide or steel. Moreover, the surface roughness of the electric discharge machining surface is 5 to 15 μm, which is equivalent to cemented carbide or steel. Furthermore, the mechanical properties at room temperature and high temperature are almost the same as other sialon.
[0040]
With the above configuration, in the disk characteristic evaluation apparatus 1, when evaluating the characteristics of the magnetic heads 15 and 17, after the magnetic disk 13 is set to a predetermined number of revolutions by the spindle motor 7, the coarse movement stage 19 is moved in the track direction, for example. The magnetic heads 15 and 17 are positioned at predetermined positions. Further, after the head loader 29 is moved in a semicircular arc shape on the segment gear 23 and a skew angle α (similar to the conventional FIG. 11) is set with respect to the tangent in the track direction, the upper and lower heads are set. The magnetic heads 15 and 17 provided on the clamps 35 and 37 are loaded by the head loader 29 so as to have a predetermined flying height with respect to the magnetic disk 13. That is, the upper head clamp 35 and the lower head clamp 37 are adjusted in the vertical direction.
[0041]
Next, in the track profile characteristic evaluation and the error rate characteristic evaluation (bathtub characteristic) in which the characteristic evaluation is performed while finely moving the track positions of the magnetic heads 15 and 17 in the track width direction, the upper and lower head clamps 35 and 37 are used. The positioning resolution of the magnetic heads 15 and 17 is improved by performing measurement while offsetting the magnetic heads 15 and 17 by a minute amount by the provided piezo stages 55. At this time, unlike the conventional case, in the present invention, the rigidity of the entire piezo stage 55 is improved by reducing the size of the piezo stage 55 and reducing the weight of the drive portion, so that the piezo actuator 77 can be driven at a high frequency.
[0042]
More specifically, in the piezo stage 55, when the piezo actuator 77 is energized, the microactuator 77 expands and contracts in proportion to the input voltage, so that the piezo element receiving portion 73 is pushed or loosened by the microactuator 77. To do. Since the piezo stage 55 has a parallel leaf spring shape, the two elastic pieces 63 and 65 are deformed, and the stage portion 59 positioned at a distance L in the forward direction from the constricted portions 67 and 69 on the base side is indicated by an arrow in FIG. It moves finely in the X axis direction. The moving distance (stroke) of the stage portion 59 is the distance from the center of the vertical width of the piezo actuator 77 in FIG. 3, in other words, the position corresponding to the constricted portion 75 of the piezo element receiving portion 73 to the constricted portions 67 and 69. It is enlarged at a mechanical ratio (L / l) of the distance L to l.
[0043]
Therefore, for example, the magnetic head 15 (down face) at the tip of the suspension 47 attached to the stage portion 59 of the piezo stage 55 in the upper head clamp 35 via the head attachment member 45 is finely adjusted in the X-axis direction.
[0044]
Further, the piezo actuator 77 has a structure that is strong against the force in the compression direction and weak against the force in the tension direction. Therefore, when the stage unit 59 collides with another device or the like, the force in the tension direction is exerted on the piezo actuator 77. If it works, the piezo actuator 77 may be damaged. Therefore, the force applied to the stage 59 at the time of the collision escapes to the shape of the portion that is likely to collide, that is, the portion on the right magnetic disk 13 side in FIG. The shape is as follows. For example, in this embodiment, a notch shape of a chamfer 79 as shown in FIGS. 2 and 3 is provided.
[0045]
With the above configuration, the piezo actuator 77 can be prevented from being damaged when the piezo stage 55 collides with another device or the like.
[0046]
In addition, this invention is not limited to embodiment mentioned above, It can implement in another aspect by making an appropriate change. In the embodiment, an example using a piezoelectric actuator as the microactuator has been described. However, a micromotor, a rotary microactor, or the like may be used.
[0047]
【The invention's effect】
As can be understood from the description of the embodiments of the invention as described above, according to the invention of claim 1, when the microactuator is energized, the microactuator stage is moved in the left-right direction by the microactuator that expands and contracts in proportion to the input voltage. Since it can be finely moved, the magnetic head attached to the microactuator stage can be finely adjusted in the horizontal direction. Since the rigidity of the entire microactuator stage is improved by reducing the size of the microactuator stage and reducing the weight of the drive part, the microactuator can be driven at a high frequency.
[0048]
According to the invention of claim 2, when the microactuator is energized, the elastic piece facing the support portion is pushed or loosened by the microactuator that expands and contracts in proportion to the input voltage, thereby deforming the two elastic pieces, The stage part located in the front direction from the base side can be moved in the left-right direction. The moving stroke of the stage portion can be increased by the mechanical ratio of the distance from the base portion to the stage portion with respect to the distance from the base portion to the microactuator.
[0049]
According to the invention of claim 3, since the microactuator has a structure strong against the force in the compression direction and weak against the force in the tensile direction, the force in the tensile direction acts on the microactuator when some external force is generated in the stage portion. However, the microactuator can be prevented from being damaged by the cutout shape in which the external force applied to the stage portion escapes in a direction acting in the compression direction with respect to the microactuator.
[Brief description of the drawings]
FIG. 1 is a perspective view of an upper head clamp according to an embodiment of the present invention as viewed from the upside.
FIG. 2 is a detailed perspective view of the piezo stage of FIG. 2;
FIG. 3 is a plan view of the piezo stage when the upper head clamp according to the embodiment of the present invention is normally attached.
FIG. 4 is a side view of a head clamp device for a disk characteristic evaluation device according to an embodiment of the present invention.
FIG. 5 is a plan view of a disk characteristic evaluation apparatus used in the embodiment of the present invention.
6 is a front view of FIG. 5. FIG.
7 is a left side view of FIG. 5. FIG.
FIG. 8 is a plan view of a conventional disk characteristic evaluation apparatus.
FIG. 9 is a plan view of a conventional head clamp device for a disk characteristic evaluation device.
FIG. 10 is a side view of a head clamp device for a conventional disk characteristic evaluation apparatus.
FIG. 11 is a schematic explanatory diagram of a skew angle with respect to a track of a conventional magnetic disk.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Disk characteristic evaluation apparatus 11 Disk clamp 13 Magnetic disk 15, 17 Magnetic head 19 Coarse movement stage 23 Segment gear 27 Head clamp apparatus 29 Head loader 35 Upper head clamp 37 Lower head clamp 45, 49 Head attachment member 55 Piezo stage (microactuator stage)
57 base part 59 stage part 63, 65 elastic piece 71 support part 73 piezo element receiving part 77 piezo actuator (microactuator)

Claims (1)

Disk characteristic evaluation with a head clamp that positions the magnetic head at a predetermined track position in order to evaluate the electromagnetic conversion characteristics of at least one of the magnetic disk and magnetic head while rotating the magnetic disk having a plurality of concentric tracks In the head clamp device for equipment,
To the head clamp, the freely microactuator stage moving in the lateral direction provided by the micro-actuator, Ri Na attach the magnetic head to the microactuator stage,
A parallel leaf spring shape in which the microactuator stage includes a base portion to be attached to the head clamp, a stage portion to which a magnetic head is attached via a head attachment member, and two parallel elastic pieces connecting the base portion and the stage portion. And a support portion is provided between the two elastic pieces so as to project from the base portion toward the front stage portion, and a micro between the support portion and one of the two elastic pieces. A head clamp device for a disk characteristic evaluation apparatus, comprising an actuator.

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