Title: Vibration-canceling mechanism and head gimbal assembly with the vibration-canceling mechanism
Abstract: A vibration-canceling mechanism includes a vibration transfer member of a plane shape inserted between a vibration-origination system having at least one resonance frequency and an object to which a vibration is applied from the vibration-origination system. The vibration transfer member has a resonance frequency equal to or near the at least one resonance frequency of the vibration-origination system. A center of one end section of the vibration transfer member is coupled by a single arm section to a center of the other end section of the vibration transfer member. The one end section of the vibration transfer member is fixed to the vibration-origination system and the other end section of the vibration transfer member is fixed to the object so that an apparent vibration of the object is substantially canceled by a resonance of the vibration transfer member.
Patent Number: 7,016,155 Issued on 03/21/2006 to Kasajima, et al.
| Inventors:
|
Kasajima; Tamon (Kwai Chung, HK);
Shiraishi; Masashi (Kwai Chung, HK)
|
| Assignee:
|
SAE Magnetics (H.K.) Ltd. (Hong Kong, CN)
|
| Appl. No.:
|
842555 |
| Filed:
|
May 11, 2004 |
Foreign Application Priority Data
| Jul 04, 2001[JP] | 2001-203277 |
| Current U.S. Class: |
360/234.6 |
| Current Intern'l Class: |
G11B 5/60 (20060101) |
| Field of Search: |
360/2346
381/353
250/306
267/140.5
73/504.16
720/688
369/247.1
49/9
188/371,268,378,379
310/321
|
References Cited [Referenced By]
U.S. Patent Documents
| 5701048 | Dec., 1997 | Kaida.
| |
| 5855260 | Jan., 1999 | Rubin.
| |
| 6003373 | Dec., 1999 | Moore et al.
| |
| 6065742 | May., 2000 | Whiteford.
| |
| 6373956 | Apr., 2002 | Varla et al.
| |
| 6381104 | Apr., 2002 | Soeno et al.
| |
| 6515835 | Feb., 2003 | Ezaki et al.
| |
| 6556384 | Apr., 2003 | Inoue et al.
| |
| 6618220 | Sep., 2003 | Inagaki et al.
| |
| 2002/0036264 | Mar., 2002 | Nakasuji et al.
| |
| Foreign Patent Documents |
| 4-295679 | Oct., 1992 | JP.
| |
Primary Examiner: Chen; Tianjie
Attorney, Agent or Firm: Buchanan Ingersoll PC
Parent Case Text
This application is a divisional of application Ser. No. 10/179,209 filed Jun.
26, 2002, now U.S. Pat. No. 6,751,062, the entire contents of which are incorporated
herein by reference.
Claims
What is claimed is:
1. A vibration-canceling mechanism comprising a vibration transfer means of a
plane shape inserted between a vibration-origination system having at least one
resonance frequency and an object to which a vibration is applied from said vibration-origination
system, said vibration transfer means having a resonance frequency equal to or
near said at least one resonance frequency of said vibration-origination system,
a center of one end section of said vibration transfer means being coupled by a
single arm section to a center of the other end section of said vibration transfer
means, said one end section of said vibration transfer means being fixed to said
vibration-origination system and said other end section of said vibration transfer
means being fixed to said object so that an apparent vibration of said object is
substantially canceled by a resonance of said vibration transfer means.
2. The mechanism as claim in claim 1, wherein said mechanism further comprises
a first damper layer provided between said other end section of said vibration
transfer means and said vibration-origination system, for attenuating the vibration
of said object.
3. The mechanism as claimed in claim 2, wherein said first damper layer is formed
by a flexible resin adhesive adhered to said vibration transfer means and to said
vibration-origination system.
4. The mechanism as claimed in claim 2, wherein said mechanism is configured
to apply a load in an up-and-down direction to said first damper layer.
5. The mechanism as claimed in claim 1, wherein said mechanism further comprises
a second damper layer provided between said one end section of said vibration transfer
means and said object, for attenuating the vibration of said object.
6. The mechanism as claimed in claim 5, wherein said second damper layer is formed
by a flexible resin adhesive adhered to said vibration transfer means and to said object.
7. The mechanism as claimed in claim 5, wherein said mechanism is configured
to apply a load in an up-and-down direction to said second damper layer.
8. The mechanism as claimed in claim 1, wherein said vibration-origination system
is a support means including a suspension, and wherein said object is a head slider
with at least one head element attached to a top end section of said suspension.
9. The mechanism as claimed in claim 8, wherein said head slider is fixed to
one surface of said vibration transfer means and said suspension is fixed to the
other surface of said vibration transfer means.
10. The mechanism as claimed in claim 8, wherein said head slider has a surface
opposite to its air bearing surface, and wherein said vibration transfer means
comprises a plane metal plate substantially in parallel with said surface opposite
to said air bearing surface.
11. The mechanism as claimed in claim 8, wherein said vibration transfer means
comprises said single arm section, said one end section a center of which is connected
one end of said arm section and said other end section a center of which is connected
the other end of said arm section.
12. The mechanism as claimed in claim 11, wherein each of said one end section
and said other end section has a plane rectangular shape.
13. The mechanism as claimed in claim 8, wherein said at least one head element
is at least one thin-film magnetic head element.
Description
FIELD OF THE INVENTION
The present invention relates to a vibration-canceling mechanism for an object
subjected to a mechanical vibration, and to a head gimbal assembly (HGA) with the
vibration-canceling mechanism.
DESCRIPTION OF THE RELATED ART
In a magnetic disk drive apparatus, thin-film magnetic head elements for writing
magnetic information into and/or reading magnetic information from magnetic disks
are in general formed on magnetic head sliders flying in operation above the rotating
magnetic disks. The sliders are supported at top end sections of suspensions of
HGAs, respectively.
In operation, the HGA and therefore the magnetic head slider are driven or swung
along a radial direction of the magnetic disk (track-width direction) by an actuator
called as a voice coil motor (VCM), and thus a position of the magnetic head element
with respect to a track in the magnetic disk is controlled.
The actuator, a drive arm coupled to the actuator and a suspension have inherent
resonance characteristics with resonance frequencies different from each other,
respectively. Thus, to the magnetic head slider attached at the top end section
of the suspension, a mechanical vibration modified by a composite characteristic
of these inherent resonance characteristics will be transferred.
In order to suppress such mechanical vibration modified by the composite resonance
characteristic, conventionally, a resonance peak of an electrical drive signal
was suppressed by at least one multi-stage filter mounted in a servo circuit of
the actuator.
However, because such electrical vibration-suppressing method needed to
provide the multi-stage filter, the servo circuit was complicated in configuration
and thus the manufacturing cost increased. Also, since the mechanical vibration
was suppressed by the electrical means not directly by a mechanical means, an efficiency
for suppression was extremely low.
The suspension has in general a torsion mode resonance other than a lateral direction
resonance in directions perpendicular to an axis in a plane of the suspension.
A lateral component of the torsion mode resonance may often produce an off-track
of the magnetic head element. Thus, the standard of the suspension severely limits
an allowable amplitude of the lateral direction vibration. Due to this limitation
of the lateral vibration amplitude, it is necessary to strictly manage the fabrication
process for forming the shape of the suspension. In other words, it is very important
to reduce a lateral component amplitude of a torsion mode resonance when designing
a suspension.
SUMMARY OF THE INVENTION
It is therefore an aim of the present invention to provide a vibration-canceling
mechanism and an HGA with the vibration canceling, whereby a mechanical vibration
applied to an object can be suppressed with efficiency without greatly changing
a conventional structure of the HGA.
Another aim of the present invention is to provide a vibration-canceling
mechanism and an HGA with the vibration canceling, whereby a lateral component
amplitude due to a torsion mode resonance can be effectively suppressed.
Further aim of the present invention is to provide a vibration-canceling
mechanism and an HGA with the vibration canceling, whereby a configuration of a
servo circuit of an actuator can be simplified.
According to the present invention, a vibration-canceling mechanism includes
a vibration transfer member of a plane shape inserted between a vibration-origination
system having at least one resonance frequency and an object to which a vibration
is applied from the vibration-origination system. The vibration transfer member
has a resonance frequency equal to or near the at least one resonance frequency
of the vibration-origination system. A center of one end section of the vibration
transfer member is coupled by a single arm section to a center of the other end
section of the vibration transfer member. The one end section of the vibration
transfer member is fixed to the vibration-origination system and the other end
section of the vibration transfer member is fixed to the object so that an apparent
vibration of the object is substantially canceled by a resonance of the vibration
transfer member.
When the vibration-origination system resonates, the vibration transfer member
also resonates. The one end section of the vibration transfer member vibrates in
phase with the vibration-origination system but the other end section of the vibration
transfer member vibrates in substantially inverted phase or deviated phase as the
vibration-origination system. Therefore, the vibration transfer member operates
so as to move a position of the object back to its original position that will
be positioned when no resonance occurs, resulting the apparent vibration of the
object to cancel.
As aforementioned, according to the present invention, only by additionally attaching
the vibration transfer member with a simple structure, the mechanical vibration
can be extremely effectively canceled without greatly changing a conventional structure
of the HGA. Also, since a configuration of a servo circuit of the actuator can
be simplified, a manufacturing cost of the magnetic disk drive apparatus can be reduced.
Also, since the vibration transfer member is configured in a plane shape, no
bending process is needed and its characteristics can be adjusted only by executing
a photo-etching process. Thus, a fabrication of the vibration transfer member can
become very easy and also extremely high precision can be expected. The latter
will present the minimum variation in the characteristics caused by a dimensional error.
Particularly, according to the present invention, because a center
of one end section of the vibration transfer member is coupled by a single arm
section to a center of the other end section of the vibration transfer member,
not only an amplitude of a resonance mode for vibrating the object in lateral directions
but also an amplitude of a lateral direction component of the torsion mode resonance
can be effectively suppressed.
It is preferred that the vibration-canceling mechanism further includes a first
damper layer provided between the other end section of the vibration transfer member
and the vibration-origination system, for attenuating the vibration of the object.
To the both surfaces of the first damper layer, vibrations of substantially inverted
phase or deviated phase with each other are applied from the vibration-origination
system and the vibration transfer member, respectively. Thus the first damper layer
operates to restrict an excessive inverse-movement of the vibration transfer member
so as to attenuate the amplitude of the vibration, and therefore the vibration
of the object fixed to the other end section of the vibration transfer member is attenuated.
It is also preferred that the vibration-canceling mechanism further includes a
second damper layer provided between the one end section of the vibration transfer
member and the object, for attenuating the vibration of the object.
Preferably, the first and/or second damper layer is formed by a flexible
resin adhesive adhered to the vibration transfer member and to the vibration-origination system.
Also it is preferred that the vibration-canceling mechanism is configured to
apply a load in an up-and-down direction to the first and/or second damper layer.
By applying the load, the damping effect of the damping layer will increase. The
resonance frequency of a system consisting of the vibration transfer member and
the damper layer varies depending upon a level of the applied load.
It is preferred that the vibration-origination system is a support member including
a suspension, and that the object is a head slider with at least one head element
attached to a top end section of the suspension.
It is further preferred that the head slider is fixed to one surface of the vibration
transfer member and the suspension is fixed to the other surface of the vibration
transfer. Since the first damper layer is provided between the other end section
of the vibration transfer member and the suspension, a gap space for inserting
an adhesive can be automatically obtained between the vibration transfer member
and the suspension. This results extremely easy assembling of the vibration transfer
member with the suspension. Also, if the second damper layer is provided between
the one end section of the vibration transfer member and the head slider, a gap
space for inserting an adhesive can be automatically obtained between the vibration
transfer member and the head slider. This results extremely easy assembling of
the vibration transfer member with the head slider.
It is preferred that the head slider has a surface opposite to its air bearing
surface (ABS), and that the vibration transfer member consists of a plane metal
plate substantialiy in parallel with the surface opposite to the ABS.
It is also preferred that vibration transfer member includes the single arm section,
the one end section a center of which is connected one end of the arm section and
the other end section a center of which is connected the other end of the arm section.
It is further preferred that each of the one end section and the other end section
has a plane rectangular shape.
It is further preferred that the at least one head element is at least one thin-film
magnetic head element.
According to the present invention, furthermore, an HGA includes a head
slider provided with at least one head element, a support member including a suspension
and having at least one resonance frequency, and a vibration transfer member of
a plane shape inserted between the suspension and the head slider to which a vibration
is applied from the support member. The vibration transfer member has a resonance
frequency equal to or near the at least one resonance frequency of the support
member. A center of rear end section of the vibration transfer member is coupled
by a single arm section to a center of a top end section of the vibration transfer
member. The rear end section of the vibration transfer member is fixed to the suspension
and the top end section of the vibration transfer member is fixed to the head slider
so that an apparent vibration of the head slider is substantially canceled by a
resonance of the vibration transfer member.
When the suspension (load beam) resonates to vibrate the flexure, the vibration
transfer member also resonates. The rear end section of the vibration transfer
member vibrates in phase with the flexure but the top end section of the vibration
transfer member vibrates in substantially inverted phase or deviated phase as the
flexure. Therefore, the vibration transfer member operates so as to move a position
of the head slider back to its original position that will be positioned when no
resonance occurs, resulting the apparent vibration of the head slider to cancel.
As aforementioned, according to the present invention, only by additionally attaching
the vibration transfer member with a simple structure, the mechanical vibration
can be extremely effectively canceled without greatly changing a conventional structure
of the HGA. Also, since a configuration of a servo circuit of the actuator can
be simplified, a manufacturing cost of the magnetic disk drive apparatus can be reduced.
Also, since the vibration transfer member is configured in a plane shape, no
bending process is needed and its characteristics can be adjusted only by executing
a photo-etching process. Thus, a fabrication of the vibration transfer member can
become very easy and also extremely high precision can be expected. The latter
will present the minimum variation in the characteristics caused by a dimensional error.
Particularly, according to the present invention, because a center
of one end section of the vibration transfer member is coupled by a single arm
section to a center of the other end section of the vibration transfer member,
not only an amplitude of a resonance mode for vibrating the object in lateral directions
but also an amplitude of a lateral direction component of the torsion mode resonance
can be effectively suppressed.
It is preferred that the HGA further includes a first damper layer provided between
the top end section of the vibration transfer member and the suspension, for attenuating
the vibration of the head slider. To the both surfaces of the first damper layer,
vibrations of substantially inverted phase or deviated phase with each other are
applied from the flexure and the vibration transfer member, respectively. Thus
the first damper layer operates to restrict an excessive inverse-movement of the
vibration transfer member so as to attenuate the amplitude of the vibration, and
therefore the vibration of the head slider fixed to the top end section of the
vibration transfer member is attenuated.
It is preferred that the HGA further includes a second damper layer provided
between
the rear end section of the vibration transfer member and the head slider, for
attenuating the vibration of the head slider.
It is also preferred that the first and/or second damper layer is formed by a
flexible resin adhesive adhered to the vibration transfer member and to the suspension.
It is further preferred that the HGA is configured to apply a load in an up-and-down
direction to the first and/or second damper layer. In the actual HGA, a load from
the suspension is applied to the vibration transfer member and a resistance force
from the recoding disk is applied to the head slider. Thus, forces in up-and-down
directions are applied to the damper layer, and therefore the damping effect of
the damping layer increases. The resonance frequency of a system consisting of
the vibration transfer member and the damper layer varies depending upon a level
of the applied load.
It is preferred that the head slider is fixed to one surface of the vibration
transfer member and the suspension is fixed to the other surface of the vibration
transfer member. Since the first damper layer is provided between the top end section
of the vibration transfer member and the suspension, a gap space for inserting
an adhesive can be automatically obtained between the vibration transfer member
and the suspension. This results extremely easy assembling of the vibration transfer
member with the suspension. Also, if the second damper layer is provided between
the rear end section of the vibration transfer member and the head slider, a gap
space for inserting an adhesive can be automatically obtained between the vibration
transfer member and the head slider. This results extremely easy assembling of
the vibration transfer member with the head slider.
It is preferred that the head slider has a surface opposite to its ABS, and that
the vibration transfer member consists of a plane metal plate substantially in
parallel with the surface opposite to the ABS.
It is also preferred that vibration transfer member includes the single arm section,
the one end section a center of which is connected one end of the arm section and
the other end section a center of which is connected the other end of the arm section.
It is further preferred that each of the one end section and the other end section
has a plane rectangular shape.
It is still further preferred that the at least one head element is at least
one
thin-film magnetic head element.
Further objects and advantages of the present invention will be apparent
from the following description of the preferred embodiments of the invention as
illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an oblique view schematically illustrating main components of a magnetic
disk drive apparatus in a preferred embodiment according to the present invention;
FIG. 2 is an oblique view illustrating the whole structure of an HGA in the
embodiment of FIG. 1;
FIG. 3 is an exploded oblique view illustrating an enlarged top end section
of the HGA, namely a flexure, a vibration transfer member and a magnetic head slider,
in the embodiment of FIG. 1;
FIG. 4 is an exploded oblique view illustrating the enlarged top end section
of the HGA in the embodiment of FIG. 1, seen from a different direction from FIG. 3;
FIG. 5 is an exploded oblique view illustrating the enlarged top end section
of the HGA in the embodiment of FIG. 1, seen from a different direction from FIG. 3;
FIG. 6 is an exploded side view illustrating the enlarged top end section of
the HGA in the embodiment of FIG. 1;
FIG. 7 is an oblique view illustrating the enlarged top end section of the HGA
in the embodiment of FIG. 1;
FIG. 8 is an oblique view illustrating the enlarged top end section of the HGA
in the embodiment of FIG. 1, seen from a different direction from FIG. 7;
FIG. 9 is a side view illustrating the enlarged top end section of the HGA in
the embodiment of FIG. 1;
FIG. 10 is a plane view used for illustrating why a mechanical vibration is
cancelled in the embodiment of FIG. 1;
FIG. 11 is a side view used for illustrating why a mechanical vibration is cancelled
in the embodiment of FIG. 1; and
FIG. 12 is an exploded oblique view illustrating an enlarged top end section
of an HGA in another embodiment according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates main components of a magnetic disk drive apparatus in a preferred
embodiment according to the present invention, FIG. 2 illustrates the whole structure
of an HGA in this embodiment, FIG. 3 illustrates an enlarged top end section of
the HGA in this embodiment, FIGS. 4 and 5 illustrate the enlarged top end section
of the HGA in this embodiment, seen from a different direction from FIG. 3, FIGS.
6 and 7 illustrate the enlarged top end section of the HGA in this embodiment,
FIG. 8 illustrates the enlarged top end section of the HGA in this embodiment,
seen from a different direction from FIG. 7, and FIG. 9 illustrates the enlarged
top end section of the HGA in this embodiment.
In FIG. 1, reference numeral
10 denotes a plurality of magnetic hard disks
rotating around an axis
11, and
12 denotes an assembly carriage device
for positioning each magnetic head element on a track of each disk. The assembly
carriage device
12 is mainly constituted by a carriage
14 capable
of rotating around an axis
13 and an actuator
15 such as for example
a VCM for driving the carriage
14 to rotate.
Base sections at one ends of a plurality of drive arms
16 stacked along
the axis
13 are attached to the carriage
14, and one or two HGAs
17 are mounted on a top section at the other end of each arm
16.
Each of the HGAs
17 has a magnetic head slider mounted at its top end section
so that the slider opposes to one surface (recording and reproducing surface) of
each of the magnetic disks
10.
As shown in FIG. 2, the HGA is assembled by fixing a vibration transfer member
21 to which a magnetic head slider
22 with a thin-film magnetic head
element
22d (FIGS. 3 and 4) is fixed, to a top end section of a suspension
20. Namely, the magnetic head slider
22 is indirectly coupled with
the suspension
20 through the vibration transfer member
21.
As shown in FIGS. 3-9, the magnetic head slider
22 has a rear end surface
22a on which the thin-film magnetic head element
22d is
formed, an ABS
22b and a surface
22c opposite to the
ABS
22b. This opposite surface
22c is tightly fixed
to the vibration transfer member
21.
The suspension
20 is substantially formed by a resilient flexure
23,
a load beam
24 supporting a rear end section of this flexure
23,
and a base plate
25 fixed to the load beam
24.
The flexure
23 has at its top end section a flexible tongue
23a
(FIGS. 3-9) provided with a proper stiffness and depressed by a dimple (not
shown) formed on the load beam
24. Onto the tongue
23a, fixed
is a rear coupling section
21a (FIG. 3) of the vibration transfer
member
21.
The flexure
23 has elasticity for supporting flexibly the magnetic head
slider
22 through the vibration transfer member
21 by this tongue
23a. This flexure
23 is made of in this embodiment a stainless
steel plate (for example SUS304TA) with a thickness of about 20 μm.
The load beam
24 is made of in this embodiment a stainless steel plate
with a thickness of about 60 μm, and fixed to the flexure
23 at its
rear end section. The fixing of the load beam
24 with the flexure
23
is performed also by pinpoint welding at a plurality of points.
The base plate
25 to be attached to the drive arm
16 shown in FIG.
1 is made of in this embodiment a stainless steel or iron plate with a thickness
of about 150 μm. This base plate
25 is fixed to a base section of
the load beam
24 by welding.
On the flexure
23 and the load beam
24, flexible conductor members
each including a plurality of trace conductors of a thin-film multi-layered pattern
are formed or disposed. However, as the present invention does not directly concern
these components, they are omitted in the drawings.
It is apparent that a structure of the suspension of the HGA, according to the
present invention is not limited to the aforementioned one. Although it is not
shown, a head drive IC chip may be mounted on a middle of the suspension
20.
As shown in FIGS. 3-9, cutting out and/or patterning a single plane metal plate
member form the vibration transfer member
21 in this embodiment. Namely,
by executing patterning such as a photo-etching for example of the metal plate
member, a plane vibration transfer member
21 with a rectangular rear end
coupling section
21a, a rectangular top end coupling section
21b
and a single arm section
21c coupling the centers of the coupling
sections
21a and
21b is formed. The arm section
21c
can freely move not only in lateral directions but also in a torsional direction
without contact to the magnetic head slider
22 and also to the flexure
23.
The metal plate for the vibration transfer member
21 in this embodiment
is made of a stainless steel and has a thickness of about 10-100 μm. As for
the metal plate, any metal material plate such as a zirconia plate, a beryllium
copper plate, an aluminum plate, a titanium plate, another metal plate or an alloy
plate may be used other than the stainless steel plate.
An upper surface of the rear end coupling section
21a of the vibration
transfer member
21 is tightly fixed to a lower surface of the tongue
23a
of the flexure
23 by an adhesive
26, and a lower surface of the
top end coupling section
21b is also tightly fixed to the opposite
surface
22c of the magnetic head slider
22 by an adhesive
27. Thus, the magnetic head slider
22 is coupled to the flexure
23
through the vibration transfer member
21. As for the adhesive
26
and
27, a cured type adhesive such as for example an epoxy base or UV-cured
adhesive may be used.
An upper surface of the top end coupling section
21b of the vibration
transfer member
21 is fixed to a top end section of the flexure
23,
namely a base section of the tongue
23a, by a soft or flexible adhesive
that functions as a damping layer
28. As for the flexible adhesive
28,
a resin adhesive such as a urethane-rubber base or acryl base pressure-sensitive
adhesive for example may be used. Thus formed damping layer
28 can effectively
attenuate amplitude of lateral vibrations of the magnetic head slider
22
due to a resonance in the lateral direction of the suspension.
FIGS. 10 and 11 illustrate why a mechanical vibration is cancelled in this
embodiment. In particular, FIG. 11 illustrates in detail a system
102 shown
in FIG. 10.
As shown in FIG. 10, when the actuator and the drive arm
16 connected
to
the actuator mechanically vibrate at a frequency f, the load beam
24 resonates
at a resonance frequency f and a vibration
101 in track-width directions
appeared at the top end of the load beam
24 is applied to the system
102
connected with this vibration-origination system
100. In the system
102
shown in FIG. 11, this lateral vibration
101 is first applied to the flexure
23. However, because a resonance frequency of the flexure
23 is sufficiently
higher than the frequency f of the vibration, the flexure
23 will not resonate.
Therefore, the flexure
23 in regions
110 and
111 will vibrate
with the same phase. Here, the top end section of the vibration transfer member
21 positions in the region
110 and the rear end section of the vibration
transfer member
21 positions in the region
111.
This vibration transfer member
21 fixed to the flexure
23 in the
region
111 will receive the vibration from the flexure
23 and vibrate
with the same phase as the flexure
23. A resonance frequency of the vibration
transfer member
21 itself is set to just or near the frequency f. Thus,
when the vibration at the frequency f is applied from the flexure
23, this
vibration transfer member
21 will resonate. Because of the resonance, a
vibration at the top end section of the vibration transfer member
21 in
a region
112 will have an inverted phase as that of the flexure
23
in the region
110. Therefore, the vibration transfer member
21 will
operate so as to move a position of the magnetic head slider
22 fixed to
the vibration transfer member
21 in the region
112 back to its original
position that will be positioned when no resonance occurs resulting the apparent
vibration of the magnetic head slider
22 to cancel.
In this embodiment, also, the damping layer
28 operates to attenuate the
vibration amplitude of the magnetic head slider
22. Namely, since the flexure
23 in the region
110 and the vibration transfer member
21
in the region
112 which sandwich the damping layer
28 move in reverse
directions and provide resistances with each other, the vibration amplitude of
the vibration transfer member
21 or the magnetic head slider
22 will
be attenuated. This attenuation of the amplitude will be established in a frequency
range near the resonance frequency, in which phases of both the vibrations are
inverted to or deviate from each other.
It is desired to apply a load or loads in up-and-down directions to the damping
layer
28. In fact, in the actual HGA, a load from the flexure
23
is applied to the vibration transfer member
21 and a resistance force from
the recoding disk is applied to the magnetic head slider
22. Thus, forces
in up-and-down directions are applied to the damper layer
28. By applying
the forces, the damping effect of this damping layer
28 will increase.
As in this embodiment, even if the vibration transfer member
21 is formed
by a stainless steel, a relatively low resonance frequency of the vibration transfer
member
21, which is substantially equal to a swaying mode frequency of the
HGA, can be attained by arranging this vibration transfer member
21 in a
top-and-rear direction that is perpendicular to the direction of the applied vibration
and by appropriately adjusting a length and a thickness of the vibration transfer
member
21.
As aforementioned, according to this embodiment, only by additionally attaching
the vibration transfer member
21 with a simple structure, for providing
a vibration-transferring loop between the tongue
23a of the flexure
23 and the magnetic head slider
22, the mechanical vibration can
be extremely effectively canceled without greatly changing a conventional structure
of the HGA. Also, since a configuration of a servo circuit of an actuator can be
simplified, a manufacturing cost of the magnetic disk drive apparatus can be reduced.
The damping layer
28 in this embodiment is provided to restrict an excessive
inverse-movement of the vibration transfer member
21 so as to attenuate
the amplitude of the vibration. Thus, providing of this damping layer is not a
necessary condition of the present invention. However, if the damping layer is
provided, not only the vibration amplitude of the magnetic head slider
22
can be effectively attenuated, but also a gap space for inserting an adhesive can
be automatically obtained between the rear end coupling section
21a of
the vibration transfer member
21 and the flexure
23 resulting extremely
easy assembling of the vibration transfer member
21 with the flexure
23.
Since the vibration transfer member
21 is configured in a plane shape,
no bending process is needed and its characteristics can be adjusted only by executing
a photo-etching process. Thus, a fabrication of the vibration transfer member can
become very easy and also extremely high precision can be expected. The latter
will present the minimum variation in the characteristics caused by a dimensional
error. Furthermore, since the top and rear end sections of the vibration transfer
member
21 are fixed by the adhesive, shock resistances in both this longitudinal
direction and in the lateral direction increase. As a result, it is possible to
shape the vibration member
21 in a thin and narrow slit shape as a longitudinally
arranged plate spring.
Particularly, according to the present invention, since the vibration
transfer member
21 has a structure with the single arm section
21c
coupled between the centers of the coupling sections
21a and
21b, not only an amplitude of a resonance mode for vibrating the
magnetic head slider in lateral directions but also an amplitude of a lateral direction
component of the torsion mode resonance can be effectively suppressed.
FIG. 12 illustrates an enlarged top end section of an HGA in another embodiment
according to the present invention.
In this embodiment, a lower surface of the rear end coupling section
21a
of the vibration transfer member
21 is fixed to the surface
22c
opposite to the ABS
22b of the magnetic head slider
22
by a soft or flexible adhesive that functions as a damping layer
29. As
for the flexible adhesive
29, a resin adhesive such as a urethane-rubber
base or acryl base pressure-sensitive adhesive for example may be used. Since the
slider
22 vibrates in response to the vibration of the top end section of
the vibration transfer member
21, both the resonance vibration at the rear
end section of the vibration transfer member
21 and the resonance vibration
at the top end section of the vibration transfer member
21 that have phases
inverted to each other or deviated from each other are applied to this damper layer
29. Thus, they provide resistances with each other and then amplitude of
vibrations of the magnetic head slider
22 is attenuated.
Since the damping layer
29 is provided between the rear end coupling
section
21a of the vibration transfer member
21 and the magnetic
head slider
22, a gap space for inserting an adhesive can be automatically
obtained between the vibration transfer member
21 and the slider
22
resulting extremely easy assembling of the vibration transfer member
21
with the magnetic head slider
22.
Other configurations, operations, advantages and modifications in this embodiment
are the same as those in the embodiment of FIG. 1. Also, in this embodiment, the
similar elements as those in the embodiment of FIG. 1 are represented by the same
reference numerals.
Structure of the vibration transfer member is not limited to those of the
aforementioned embodiments. Any shaped vibration transfer member provided with
a plane shape structure ready for a torsion mode resonance may be utilized.
In the aforementioned embodiments, HGAs having magnetic head sliders with thin-film
magnetic head elements are described. However, it is apparent that the present
invention can be applied to an HGA with a head element such as an optical head
element other than the thin-film magnetic head element.
Many widely different embodiments of the present invention may be constructed
without departing from the spirit and scope of the present invention. It should
be understood that the present invention is not limited to the specific embodiments
described in the specification, except as defined in the appended claims.
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