JP3669923B2 - Magnetic head suspension - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic head suspension with a fine movement actuator that supports a magnetic head for a hard disk drive (HDD) and can finely move the magnetic head.
[0002]
[Prior art]
In the HDD, the track density is increased as the recording density is increased, and a product exceeding 20 kTPI (Tracks per inch) has been commercialized. If the track density further increases in the future, it is expected that it will become difficult to position the magnetic head only with an actuator using the current VCM (Voice Coil Motor). From such a viewpoint, in addition to the conventional VCM, a method of positioning the magnetic head with high accuracy by adopting a two-stage actuator type having a fine actuator between the VCM and the magnetic head has been proposed.
[0003]
A fine actuator using the expansion / contraction operation of a piezoelectric element, which is disposed between a base plate and a load beam in a magnetic head suspension, is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-16311, Japanese Patent No. 2529380, and “Piezoelectric” Microactuator for Dual Stage Control "(RBEvans et al, IEEE Transaction on Magnetics, Vol. 35 No. 2 pp.977-982, March 1999).
[0004]
The fine actuator described in the prior art document includes two piezoelectric elements and a hinge portion on which the piezoelectric elements are disposed. The hinge portion includes a base plate side substrate portion joined to the base plate, a load beam side substrate portion joined to the load beam, and a plurality of beam portions connecting the both substrate portions. The two piezoelectric elements are arranged so as to extend over the base plate side substrate portion and the load beam side substrate portion of the hinge portion, and further, when one of them extends, the other contracts. Therefore, by extending and contracting the two piezoelectric elements, the load beam side substrate portion rotates with respect to the base plate side substrate portion, whereby the magnetic head attached to the tip end portion of the load beam moves the actuator and the magnetic head. The head suspension moves in a direction perpendicular to the central axis of the head suspension. In general, since the central axis of the magnetic head suspension is oriented substantially in the same direction as the track tangential direction of the portion where the magnetic head is located, the magnetic head moves in a direction crossing the track by the expansion / contraction operation of the fine actuator. .
[0005]
[Problems to be solved by the invention]
By the way, in order to perform high-precision positioning control of the magnetic head while stabilizing the floating characteristics of the magnetic head, the hinge portion basically has rigidity in the rotational direction of the actuator, that is, the base plate. It is preferable that the side substrate portion and the load beam side substrate portion have low rigidity in the substrate surface direction and high rigidity in the direction perpendicular to the substrate surface (hereinafter referred to as longitudinal rigidity).
[0006]
That is, when the rigidity of the hinge portion in the direction of rotation of the actuator is high, when the beam portion is deformed by expansion and contraction of the piezoelectric element, a reaction force that the piezoelectric element receives from the substrate portion becomes large. There is a risk that the amount of expansion and contraction decreases. Such a decrease in the amount of expansion / contraction of the piezoelectric element causes an increase in the voltage applied to the piezoelectric element when a desired amount of displacement of the magnetic head is obtained.
[0007]
On the other hand, when the longitudinal rigidity of the hinge portion is low, the longitudinal force applied to the piezoelectric element increases. That is, in the magnetic head suspension, a load bending region is formed at the base of the load beam in order to generate a force (load) for pressing the magnetic head against the disk surface. However, if the longitudinal rigidity of the hinge portion is low, A longitudinal force is applied to the piezoelectric element. Addition of a longitudinal force to such a piezoelectric element causes an increase in stress applied to the adhesive layer that joins the piezoelectric element and the substrate portion in the hinge portion, and reduces the reliability of this joining.
[0008]
As a method of increasing the longitudinal rigidity of the hinge part, means such as increasing the number of beams, increasing the width of the beam, or shortening the length of the beam are conceivable. Will also increase.
[0009]
The present invention has been made in view of the above problems in the prior art, and provides a magnetic head suspension with a fine motion actuator that can increase the longitudinal rigidity while effectively preventing an increase in the rigidity of the hinge portion in the rotational direction. With the goal.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a base plate, a load beam, and a fine actuator disposed between the base plate and the load beam to connect the two and swing the load beam with respect to the base plate. The fine head actuator includes a hinge portion and at least a pair of piezoelectric elements, and the hinge portion is connected to the base plate side substrate portion connected to the base plate and the load beam. A load beam side substrate portion and a beam portion connecting the base plate side substrate portion and the load beam side substrate portion, and the pair of piezoelectric elements has a distal end portion and a base end portion, respectively, of the load beam side substrate portion. and it is connected to the base plate side substrate part, and, as if one is extended and the other shortened The beam portion has a proximal end portion and a distal end portion connected to the base plate side substrate portion and the load beam side substrate portion, respectively, and a fine movement actuator is provided on the longitudinal center axis between the both end portions. A central beam configured so that the rotation center axis of the central beam is positioned, and at least a pair of side beams disposed on both sides of the central beam, each side beam including the base plate side substrate portion and the load beam At least a pair of side portions each having a base end portion and a tip end portion respectively connected to the side substrate portion and configured such that the longitudinal center axis of each side beam intersects the rotation center axis of the fine actuator possess a beam, the central axis of rotation of said fine actuator to provide a magnetic head suspension is positioned at a point L / 3 from the proximal end of the central beam.
[0011]
Preferably, each of the central longitudinal axis of said at least one pair of side beams can be made to intersect in pairs to such an angle to the longitudinal central axis of the central beam.
In one aspect, the said hinge part shall be integrally formed with the said base plate.
In another aspect, the hinge portion may be formed integrally with the load beam.
Furthermore, in another aspect, the hinge portion can be separate from the base plate and the load beam.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, a preferred embodiment of a magnetic head suspension with a fine actuator according to the present invention will be described with reference to the accompanying drawings.
FIGS. 1 and 2 are a front view (viewed from the magnetic disk side) and a rear view of the magnetic head suspension 1 with a fine actuator according to the present embodiment, respectively. FIG. 3 is a front view of the magnetic head suspension in a state before the piezoelectric element is bonded. Further, FIG. 4 is a front view of a single-layer piezoelectric element used for a fine actuator, and FIG. 5 is an enlarged front view of a hinge part and a base plate.
[0013]
1 to 3, the magnetic head suspension 1 according to the present embodiment includes a base plate 10 attached to a support shaft such as a carriage arm, a load beam 20 extending forward from the base plate 10, A fine movement actuator 30 disposed between the base plate and the load beam and connecting both members, a flexure 40 joined to the load beam 20 along the longitudinal direction, and a magnetic head (not shown) supported by the flexure 40 And.
[0014]
A VCM (not shown) that functions as a coarse actuator is attached to the base of the support shaft to which the base end of the base plate is attached. By operating the VCM, the entire magnetic head suspension is attached to the magnetic disk. Coarse movement is made.
[0015]
The base plate 10 is formed with a boss portion 11 for ball insertion on the base end side, and the base plate 10 is attached to the support shaft by caulking the boss portion 11 with respect to the support shaft. The base plate 10 can be formed of stainless steel having a thickness of about 0.2 mm, for example.
[0016]
The load beam 20 has a load bending portion 21 on the base end side, and a flange bending portion 22 for increasing rigidity in a region other than the load bending portion 21. The load bending portion 21 is bent in the direction in which the load beam 20 approaches the magnetic disk (above the paper surface in FIGS. 1 and 3), and when the magnetic head suspension 1 is mounted on the HDD. The load bending portion 21 is bent back by a predetermined amount, whereby a load for pressing the magnetic head against the magnetic disk is generated. The load beam 20 can be formed using, for example, stainless steel having a thickness of 0.03 to 0.07 mm.
[0017]
The flexure 40 is provided to support the magnetic head in a state in which it can move flexibly in the pitch direction and the roll direction. By providing the flexure 40, the magnetic head can follow the undulation of the magnetic disk. It becomes.
As shown in FIG. 3, the flexure 40 has a magnetic head mounting portion 41 at the tip. A projection 23 called a dimple formed at the tip of the load beam is always in contact with the back surface side of the magnetic head mounting portion 41, and the load by the load bending portion 21 of the load beam 20 passes through the projection 23. It acts on the magnetic head. The flexure 40 further has a head signal wiring 42 for electrically connecting the magnetic head and an external member. Preferably, the head signal wiring 42 is formed integrally with the flexure substrate. The head signal wiring 42 has a magnetic head side terminal 42a and a head signal wiring terminal 42b at the distal end portion and the proximal end portion, respectively. The magnetic head side terminal 42a is connected to the terminal of the magnetic head by gold boulding or the like, while the head signal wiring terminal 42b is connected to an FPC (not shown). The head signal wiring terminal 42 b can be positioned on a flexure pad stage 43 disposed on the side of the fine actuator 30. Preferably, the pad stage 43 can be provided with a piezoelectric element terminal 42c serving as a connection portion with a piezoelectric element described later.
[0018]
Such a flexure 40 may have, for example, a substrate made of stainless steel having a thickness of 0.02 to 0.03 mm, and each pattern of a polyimide insulating layer, a wiring conductor made of copper, and a polyimide protective layer is laminated on the substrate. Can be formed. The flexure can be joined to the load beam by welding.
[0019]
The fine actuator 30 includes a hinge portion 31 that connects the base plate 10 and the load beam 20, and at least a pair of piezoelectric elements 35 disposed on the hinge portion 31.
[0020]
The hinge portion 31 includes a base plate side substrate portion 32 connected to the base plate 10, a load beam side substrate portion 33 connected to the load beam 20, and a beam portion 34 connecting both the substrates 32 and 33. Have. In this embodiment, as well shown in FIGS. 3 and 5, the base plate side substrate portion 32 is formed integrally with the base plate 10, while the load beam side substrate portion 33 is welded to the load beam 20. Etc. are joined together. The term “connected to the base plate or the load beam” is a concept including an aspect in which the base plate or the load beam is integrally formed.
[0021]
The beam portion 34 includes a central beam 34a disposed in the center and a pair of side beams 34b disposed on both sides of the central beam 34a.
[0022]
As shown in FIGS. 1 and 3, the central beam 34a has an actuator oscillation center line whose longitudinal center axis extends through a rotation center axis 50 of an actuator described later and extends parallel to the longitudinal axis of the magnetic head suspension. 51 is located. The pair of piezoelectric elements 35 are arranged on both sides of the central beam 34a so that the expansion / contraction direction is along the longitudinal direction of the magnetic head suspension. Specifically, the piezoelectric element 35 has a rectangular parallelepiped shape having a longitudinal axis along the longitudinal direction of the magnetic head suspension, and the distal end portion and the proximal end portion thereof are the load beam side substrate portion 33 and the base plate side substrate portion 32, respectively. It is connected to. Each piezoelectric element 35 includes a piezoelectric element polarized in a thickness direction perpendicular to the substrate surface of the hinge portion 31, and electrodes made of Cr / Au or the like disposed on the upper and lower surfaces of the piezoelectric member. And a member. The polarization directions of the pair of piezoelectric elements 35 are opposite to each other, so that when a voltage is applied in the thickness direction, one piezoelectric element expands and the other piezoelectric element shortens, and the magnetic head The actuator swings about the rotation axis 50 of the actuator.
[0023]
On the other hand, the side beam 34b has a distal end portion connected to the load beam side substrate portion 33 and a proximal end portion connected to the base plate side substrate 32 so that the respective longitudinal center axes thereof intersect the actuator rotation axis 50. Has been. Preferably, the side beams 34b can be a pair of beams arranged on both sides of the central beam 34a, and the respective inclination angles with respect to the central beam 34a can be made equal.
[0024]
The central beam 34a and the side beam 34b thus configured act as a cantilever beam and a both-end fixed beam, respectively. Hereinafter, the operation of each beam will be described in detail.
That is, the actuator rotation center shaft 50 is located on the central beam 34a. Therefore, when the piezoelectric element 35 is operated to swing the magnetic head around the actuator rotation axis 50, the central beam 34a is fixed at the base end and only the tip is around the actuator rotation axis 50. Will swing. That is, when the piezoelectric element 35 is operated, the central beam 34a bends in the horizontal direction between the proximal end portion and the distal end portion. As described above, the central beam 34a in which the actuator rotation center shaft 50 is located between the base end portion and the tip end portion acts as a cantilever with respect to the load in the actuator rotation direction. The position in the longitudinal direction of the central beam of the actuator rotation center shaft 50 will be described later.
[0025]
On the other hand, as described above, the pair of side beams 34b has the load beam side substrate 33 and the base plate at the distal end and the proximal end, respectively, so that the respective longitudinal central axes intersect the actuator rotation central axis 50. It is connected to the side substrate 32. Accordingly, when the magnetic head is swung by the action of the piezoelectric element 35, the side beam 34b does not bend between the distal end portion and the proximal end portion but around the actuator rotation center axis 50. It will move as a whole. Thus, the side beam 34b acts as a both-ends fixed beam with respect to the load in the actuator rotation direction. The side beam 34b can be regarded as acting as a cantilever beam with respect to a longitudinal load.
[0026]
The piezoelectric element 35 may have various sizes, for example, a length of 1.0 mm to 5.0 mm, a width of 0.8 mm to 2.0 mm, and a thickness of 0.12 mm to 0.25 mm. The thicknesses of the piezoelectric member and the electrode member can be set to, for example, 0.10 mm to 0.20 mm and 0.1 to 1 μm, respectively.
For connecting the base plate side substrate portion 32 and the load beam side substrate portion 33 to the piezoelectric element 35, for example, a conductive adhesive containing metal fine particles such as silver as a filler can be used. The adhesion region can be, for example, a region of about 0.3 mm at each of the proximal end portion and the distal end portion of the piezoelectric element 35.
[0027]
Further, the electrode of the piezoelectric element 35 that is not bonded to the hinge portion 31 is connected to a piezoelectric element terminal 42c formed on the flexure by a gold wire formed by ultrasonic bonding. In such a configuration, if the hinge portion 31 is set to the ground potential, the expansion and contraction of the piezoelectric element 35 can be controlled with high controllability only by changing the voltage applied to the piezoelectric element terminal 42c.
[0028]
The magnetic head suspension 1 configured as described above has the following effects. That is, in the hinge portion in the conventional magnetic head suspension, all the beams act as both-end fixed beams. When such a hinge structure is used, if the number of beams is increased to increase the longitudinal rigidity, the rigidity in the direction of rotation of the actuator is also proportionally increased.
On the other hand, in the present embodiment, as described above, the hinge portion 31 having the central beam 34a acting as a cantilever beam with respect to the load in the rotation direction of the actuator is provided. Therefore, in this embodiment, it is possible to effectively prevent an increase in the rigidity in the actuator rotation direction while obtaining a sufficient vertical rigidity. Hereinafter, such an effect will be described in detail.
[0029]
FIG. 6 is a diagram schematically illustrating the bending of the cantilever when a load is applied to the tip of the cantilever. In FIG. 6, the longitudinal direction of the cantilever is taken as the x-axis, and the load application direction is taken as the y-axis. When a force F in the y-axis direction is applied to the tip of the cantilever, assuming that the deflection δ of the tip of the cantilever is small,
y = F / YI × (lx 2/2-x 3/6)
dy / dx = F / YI × (lx-x 2/2)
It becomes. Here, Y is Young's modulus, and I is the second moment of section.
[0030]
Therefore, the angle Δθ formed by the tangent at the tip of the cantilever with respect to the x axis and the displacement δ of the tip of the cantilever are:
tan △ θ = [dy / dx ] x = l = (F / YI) × (l 2/2)
_{δ = [y] x = l} = (F / YI) × (l 3/3)
It becomes. From both equations, the x coordinate x _c of the point where the tangent at the tip of the cantilever crosses the x axis is:
x _c = l-δ / tan △ θ = l / 3
It becomes. Thus, x _c is independent of the force applied to the beam, it determined only by the length of the beam. The x _c corresponds to the position of the actuator rotation center shaft 50 in the longitudinal direction of the central beam. That is, if the length of the central beam 34a is L, the actuator rotation center shaft 50 is located at a point L / 3 from the base end of the central beam 34a. For example, if the length of the central beam 34a is 1.2 mm, the actuator rotation central axis 50 is located on the central axis in the longitudinal direction of the central beam 34a and about 0.4 mm from the base end. Become.
[0031]
Here, the rigidity in the rotational direction of the beam around the actuator rotation center axis (the moment of force generated when rotating by an angle of 1 radian) is considered. If the rotational moments of one cantilever and one fixed beam are K _h1 and K _h2 ,
K _h1 = Yt _s W ₁ ³ / 9l ₁・ ・ ・ (1)
K _h2 = (Yt _s W ₂ ³ / l ₂ ³ ) × (q + l ₂ ) ² (2)
It becomes. Here, t _s is the thickness of the beam, W ₁ and l ₁ are the width and length of the cantilever beam (center beam 34a), and W ₂ and l ₂ are the width and length of the both-end fixed beam (side beam 34b). Here, q is the horizontal distance between the actuator rotation center axis 50 and the end portion closer to the actuator rotation center axis 50 among the both ends of the fixed beam at both ends.
[0032]
The equation (2) is approximately established because the rotation amount is very small.
Thus, the central beam 34a of the width and length of W ₁ = 0.30 mm and l ₁ = 1.19 mm, the width and length of the side beams 34b and W ₂ = 0.20 mm and l ₂ = 1.10 mm, and, When q = 1.10 mm, the Young's modulus of stainless steel Y = 1.93 × 10 ¹¹ N / m ² , so from the above formula (1) and formula (2),
K _h1 = 0.10N ・ m / rad
K _h2 = 1.15N ・ m / rad
It becomes. Thus, the rotational direction rigidity of one end-fixed beam is 10 times or more the rotational direction rigidity of one cantilever beam.
[0033]
As described above, in the hinge portion in the conventional magnetic head suspension, all the beams are fixed at both ends. On the other hand, in the present embodiment, the central beam 34a acts as a cantilever beam with respect to the load in the actuator rotation direction. Therefore, the magnetic head suspension 1 according to the present embodiment can reduce the rigidity in the direction of rotation of the actuator as compared with the conventional case.
[0034]
On the other hand, the longitudinal rigidity of the cantilever is as follows. That is, if the longitudinal rigidity of the cantilever is K _h1v ,
^{_{K h1v = Yt s 3 W 1}} / 9l 1 ··· (3)
It becomes. Substituting the same dimension values into the above equation (3) yields K _h1v = 0.0467 N · m / rad.
Here, when a force F _h1v in the vertical direction (perpendicular to the substrate surface) is _applied to the tip of the cantilever, the displacement δ _{h1v of the} tip of the cantilever is
_{δ h1v = F h1v (l 1} -x c) 2 / K h1v = F h1v / K h1v × (2l 1/3) 2
It is represented by For example, when F _h1v = 10 gf, the longitudinal displacement Δ _h1v = 1.3 μm.
[0035]
The longitudinal rigidity of the entire hinge portion in the present embodiment is equal to the rigidity of one central beam 34a acting as a cantilever beam determined by such calculation, and the rigidity of two side beams 34b acting as both-end fixed beams. Therefore, even if a force of 10 gf is applied to the tip of the central beam 34a (cantilever beam), the longitudinal displacement of the entire hinge portion is considered to be 1 μm or less.
[0036]
Thus, in the fine movement actuator 30 of the magnetic head suspension 1 according to the present embodiment, the hinge portion 31 can effectively support the longitudinal load without imposing an excessive burden on the piezoelectric element 35. Therefore, it is possible to effectively prevent deterioration of the adhesive layer that joins the piezoelectric element 35 and the hinge portion 31, and to stabilize the floating characteristics of the magnetic head.
[0037]
Next, based on the rigidity of the beam, the relationship between the displacement of the magnetic head with respect to the applied voltage and the distance rd (see FIG. 1) between the actuator rotation center axis and the piezoelectric element center axis, and the main resonance frequency of the fine actuator and the rd Consider the relationship. 7 and 8 show the rd dependence of the displacement / applied voltage of the magnetic head and the rd dependence of the fine resonance actuator main resonance frequency, respectively. The piezoelectric element width was 1.2 mm, and the piezoelectric element thickness tp was 0.12 mm, 0.13 mm, and 0.20 mm.
[0038]
As shown in FIG. 7, when rd is 1.3 mm and the piezoelectric element thickness tp is 0.15 mm, the head displacement / applied voltage is 0.028 μm / V. When the piezoelectric element thickness tp is 0.12 mm, the head displacement / applied voltage is 0.033 μm / V. Thus, in the magnetic head suspension 1 according to the present embodiment, the magnetic head can be moved sufficiently finely.
[0039]
Further, as apparent from FIG. 8, when rd is 0.6 mm to 0.7 mm or more, the main resonance frequency of only the fine actuator 30 exceeds 10 kHz. Therefore, if a load beam having a main resonance frequency exceeding 10 kHz is used, a frequency exceeding 10 kHz can be obtained as the main resonance frequency of the entire magnetic head suspension with a fine actuator. Thus, in the magnetic head suspension 1 according to the present embodiment, the main resonance frequency of the entire suspension can be increased, thereby enabling high-speed position control of the magnetic head.
[0040]
As described above, in the magnetic head suspension with fine movement actuator 1 according to the present embodiment, sufficient longitudinal rigidity can be obtained without increasing the rotational direction rigidity. Therefore, a sufficient amount of displacement of the magnetic head can be obtained while effectively preventing load deterioration. In addition, the main resonance frequency of the entire magnetic head suspension can be increased, thereby moving the magnetic head head at high speed.
[0041]
Embodiment 2. FIG.
Next, another embodiment of the magnetic head suspension with fine movement actuator 1 'according to the present invention will be described. 9 and 10 show a back view and a front view, respectively, of the magnetic head suspension 1 ′ according to the present embodiment before mounting the piezoelectric element. In addition, the same code | symbol is attached | subjected to the same or equivalent member in the said Embodiment 1, and the description is abbreviate | omitted.
[0042]
As shown in FIGS. 9 and 10, the present embodiment is different from the first embodiment only in the structure of the hinge portion 31 ′. That is, the hinge portion 31 ′ of the fine actuator in the magnetic head suspension according to the present embodiment is formed integrally with the load beam 20 instead of the base plate 10. The hinge part 31 'is connected to the base plate 10 by welding.
[0043]
As described in the first embodiment, generally, the load beam 20 is formed of stainless steel having a thickness of 0.03 to 0.07 mm, and the base plate 10 is formed of stainless steel having a thickness of about 0.2 mm. Therefore, in the present embodiment, the thickness of the hinge portion 31 ′ can be reduced as compared with the first embodiment, thereby reducing the rigidity of the beam and obtaining a larger head displacement. it can.
[0044]
Embodiment 3 FIG.
The following will describe still another embodiment of the magnetic head suspension with a fine actuator according to the present invention. 11 and 12 are a rear view and a front view, respectively, of the magnetic head suspension 1 ″ according to the third embodiment before the piezoelectric element is mounted. Note that the same or corresponding members as those of the above-described embodiment are the same. Reference numerals are assigned and explanations thereof are omitted.
[0045]
As shown in FIGS. 11 and 12, this embodiment is different from the above embodiments only in the structure of the hinge portion 31 ″. That is, in the magnetic head suspension 1 ″ according to this embodiment. The hinge portion 31 ″ of the fine actuator is a separate member from the base plate 10 and the load beam 20. The hinge portion 31 ″ includes a base plate side substrate and a load beam side substrate, respectively, as a base plate and a load beam. It has superposed | polymerized and it connects by welding in this superposition | polymerization part.
[0046]
In the third embodiment, since the thickness of the hinge portion can be freely selected, the degree of freedom in designing the beam can be expanded in addition to the effects in the respective embodiments.
[0047]
【The invention's effect】
A magnetic head suspension with a fine actuator according to the present invention includes a hinge portion having a beam portion for connecting a base plate side substrate portion and a load beam side substrate portion, and a distal end portion and a base end portion which are the load beam side substrate portion and the load beam, respectively. A fine movement actuator is provided that includes at least a pair of piezoelectric elements that are coupled to the side substrate portion and configured such that when one is extended, the other is shortened. The beam portion intersects the central beam having a length L configured so that the rotation center axis of the fine movement actuator is positioned on the longitudinal center axis, and the longitudinal center axis intersects with the rotation center axis of the fine movement actuator. And at least a pair of side beams configured as described above, and a rotation center axis of the fine actuator is located at a point of L / 3 from a base end portion of the center beam. Therefore, the central beam acts as a cantilever with respect to the rotation direction load, the pair of side beams located on both sides of the central beam is because they act as a fixed-fixed beam, the rotational direction of the hinge portion The longitudinal rigidity can be increased while effectively preventing the increase in rigidity. Therefore, a sufficient amount of displacement of the magnetic head can be obtained while effectively preventing load deterioration.
[0048]
Further, if the inclination angles of the at least one pair of side beams with respect to the central beam are made equal, the rigidity in both the rotational directions of the hinge portion can be made uniform, whereby the magnetic head can be applied to the voltage applied to the piezoelectric element. The amount of displacement can be made equal in both directions of rotation.
[Brief description of the drawings]
FIG. 1 is a front view (viewed from a magnetic disk side) in a first embodiment of a magnetic head suspension 1 with a fine actuator according to the present invention.
FIG. 2 is a back view of the magnetic head suspension shown in FIG. 1;
FIG. 3 is a front view of the magnetic head suspension shown in FIGS. 1 and 2 before mounting a piezoelectric element.
4 is a front view of a piezoelectric element in the magnetic head suspension shown in FIGS. 1 and 2. FIG.
5 is an enlarged front view of a hinge portion in the magnetic head suspension shown in FIGS. 1 and 2. FIG.
FIG. 6 is a diagram schematically illustrating the bending of a cantilever beam when a load is applied to the distal end portion.
FIG. 7 is a graph showing the relationship between magnetic head displacement and actuator rotation central axis-piezoelectric element central axis distance rd with respect to applied voltage.
FIG. 8 is a graph showing the relationship between the main resonance frequency of only the fine actuator and rd.
FIG. 9 is a rear view of another embodiment of the magnetic head suspension with a fine actuator according to the present invention, showing a state before the piezoelectric element is mounted.
FIG. 10 is a front view of the magnetic head suspension shown in FIG. 9;
FIG. 11 is a back view of still another embodiment of the magnetic head suspension with a fine actuator according to the present invention, showing a state before the piezoelectric element is mounted.
FIG. 12 is a front view of the magnetic head suspension shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic head suspension 10 Base plate 20 Load beam 30 Fine movement actuator 31 Hinge part 32 Base plate side board | substrate part 33 Load beam side board | substrate part 34a Center beam 34b Side beam 35 Piezoelectric element

Claims (5)

A magnetic head suspension comprising a base plate, a load beam, and a fine movement actuator disposed between the base plate and the load beam to connect the two and swing the load beam with respect to the base plate,
The fine actuator includes a hinge part and at least a pair of piezoelectric elements,
The hinge portion has a base plate side substrate portion connected to the base plate, a load beam side substrate portion connected to the load beam, and a beam portion connecting the base plate side substrate portion and the load beam side substrate portion. And
The pair of piezoelectric elements are configured such that a distal end portion and a proximal end portion are connected to the load beam side substrate portion and the base plate side substrate portion , respectively, and when one of them extends, the other shortens.
The beam portion has a proximal end portion and a distal end portion connected to the base plate side substrate portion and the load beam side substrate portion, respectively, and the rotation central axis of the fine actuator is on the longitudinal central axis between the both end portions. A central beam of length L configured to be positioned;
At least a pair of side beams arranged on both sides of the central beam, each side beam having a base end portion and a tip end portion connected to the base plate side substrate portion and the load beam side substrate portion, respectively. and, and, and at least I have a pair of side beams longitudinal central axis of each side beam is configured to intersect at the central axis of rotation of said fine actuator,
The magnetic head suspension according to claim 1, wherein a rotation center axis of the fine actuator is located at a point of L / 3 from a base end portion of the central beam . It said at least a pair of side each longitudinal central axis of the beam, the magnetic head suspension according to claim 1, characterized in that intersect in pairs to such an angle to the longitudinal central axis of the central beam.   The magnetic head suspension according to claim 1, wherein the hinge portion is integrally formed with the base plate.   The magnetic head suspension according to claim 1, wherein the hinge portion is integrally formed with the load beam.   3. The magnetic head suspension according to claim 1, wherein the hinge portion is separate from the base plate and the load beam.

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