Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
1999-11-17
2001-11-06
Ometz, David L. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06313971
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a suspension for supporting a magnetic head of a disk unit incorporated in an information processing apparatus, such as a personal computer, and more particularly to an attachment structure for a flexure of the suspension.
FIG. 9
shows a part of a hard disk drive (HDD)
1
. A carriage
2
of the HDD
1
can be turned around a shaft
2
a
by means of a positioning motor
3
such as a voice coil motor. The carriage
2
is composed of a coil portion
5
located near a magnet
4
of the motor
3
, arms (actuator arms)
6
fixed to the coil portion
5
, suspensions
7
attached individually to the respective distal end portions of the arms
6
, magnetic heads
8
on the respective distal end portions of the suspensions
7
, etc. Each head
8
can be moved to a desired track (recording surface) of each of disks
9
by driving the carriage
2
by means of the motor
3
.
Each head
8
is provided with a slider
10
in a position such that it can face the track of each disk
9
, a transducer (not shown) held on the slider
10
, etc. When the disk
9
rotates at high speed, the slider
10
is slightly lifted above the surface of the disk
9
, whereby an air bearing is formed between the disk
9
and the slider
10
.
FIG. 10
shows an example of the conventional suspension
7
. The suspension
7
includes a load beam
11
formed of a thin precision plate spring, a flexure
12
formed of a very thin plate spring fixed to the load beam
11
and a base plate
13
fixed to the proximal portion of the load beam
11
, etc. The slider
10
is provided on the distal end portion of the flexure
12
. The flexure
12
has rather low stiffness such that the attitude of the lifted slider
10
can flexibly change with respect to the disk
9
. The load beam
11
and the flexure
12
are fixed to each other by laser welding or the like in a manner such that they are put in layers in the thickness direction.
A dimple
14
is provided on the distal end portion of the load beam
11
. Although the dimple
14
is a hemispherical protuberance that projects toward the slider
10
, it is called a dimple in the art because it is recessed on the backside of the load beam
11
. As the tip of the dimple
14
abuts on the flexure
12
, the head
8
can make three-dimensional displacements, such as pitching and rolling around the dimple
14
. In some cases, the dimple
14
may be provided on the flexure
12
in place of the load beam
11
.
The load beam
11
and the flexure
12
must be accurately positioned before they are fixed to each other. Conventionally, to attain this, reference holes
15
and
16
are formed in the load beam
11
and the flexure
12
, respectively. The laser welding or the like is carried out with a jig pin
17
in the holes
15
and
16
and with the load beam
11
and the flexure
12
clamped in the thickness direction between a pad
18
and a presser member
19
of a clamping device, as shown in FIG.
11
.
In order to prevent the jig pin
17
from damaging the load beam
11
or the flexure
12
as it is inserted into the reference holes
15
and
16
, in the prior art example, clearances C
1
and C
2
are required between the outer peripheral surface of the pin
17
and the inner peripheral surface of the holes
15
and
16
. Possibly, however, these clearances C
1
and C
2
may cause the reference holes
15
and
16
to be correspondingly dislocated in the crosswise direction with respect to the jig pin
17
, as shown in FIG.
12
. Thus, the load beam
11
and the flexure
12
may be subjected to a maximum center deviation of (C
1
+C
2
)/2.
If the load beam
11
and the flexure
12
are dislocated in this manner, moments that act on the slider
10
are unbalanced. It is known that the flying height characteristic of the head
8
for the disk is greatly influenced by the moments that act on the slider
10
. In order to obtain a steady flying height characteristic, therefore, moments in the rolling direction, in particular, are expected to be distributed equally.
The imbalance of the moments in the rolling direction is attributable to the static rolling angle and dislocation of the dimple
14
. In the case where the dimple
14
is provided on the flexure
12
, as shown in
FIG. 13
, the center deviation of the flexure
12
with respect to the load beam
11
is regarded directly as a dimple dislocation &Dgr;D. In the case where the dimple
14
is provided on the load beam
11
, as shown in
FIG. 14
, on the other hand, the center deviation between the load beam
11
and the flexure
12
causes a moment deviation &Dgr;M, and therefore, imbalance of moments attributable to the static rolling angle.
In order to obtain the steady flying height characteristic, therefore, the center deviation between the load beam
11
and the flexure
12
must be minimized. In practice, however, the accuracy of assembly of the load beam
11
and the flexure
12
is subject to variation, so that it is hard to obtain the steady flying height characteristic.
If the relative positions of the load beam
11
and the flexure
12
are deviated, moreover, the following problem will be aroused. To meet the demand for downsizing of heads, wired suspensions have recently been put to practical use. Electrode pads of the wired suspensions are located on the flexure. In consequence, dislocation of the flexure with respect to the load beam causes dislocation of the electrode pads, thus hindering the attachment of magnetic heads.
BRIEF SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide a magnetic head supporting suspension in which the relative positions of a load beam and a flexure can be accurately regulated to solve the aforementioned problems.
In order to achieve the above object, according to the present invention, there is provided a suspension provided with a load beam and a flexure, comprising a reference hole formed in the load beam or the flexure and a burred hole formed in the flexure or the load beam and having a flange portion rising from the inner peripheral edge thereof and capable of being fitted into the reference hole with the flexure on top of the load beam. The load beam and the flexure are formed of a hard metal plate (material for spring) each.
In fixing the load beam and the flexure of the suspension of the invention constructed in this manner, they are positioned with respect to each other by fitting the flange portion of the burred hole into the reference hole. The load beam and the flexure are fixed to each other by adhesive bonding or welding in a manner such that they are restricted in the thickness direction. Since the inside diameter of the reference hole and the outside diameter of the flange portion of the burred hole should only be adjusted to values such that they can engage each other, the clearance between the reference hole and the flange portion can be reduced or approximated to zero.
According to the invention, the load beam and the flexure are positioned by directly fitting the reference hole and the flange portion of the burred hole therein with each other. Thus, the relative positions of the load beam and the flexure can be accurately regulated, so that the two members can enjoy high position accuracy and good assembly symmetry. Thus, the flying height characteristic of a head and the position accuracy of electrode pads of the wired suspension are improved.
Preferably, a suspension according to the invention comprises a first reference hole formed in the load beam or the flexure, a first burred hole formed in the flexure or the load beam and having a flange portion rising from the inner peripheral edge thereof and capable of being fitted into the first reference hole with the flexure on top of the load beam, a second reference hole formed in the load beam or the flexure and spaced from the first reference hole in the longitudinal direction of the suspension, and a second burred hole formed in the flexure or the load beam and having a flange portion rising from the inner peripheral edge
Araki Nobuo
Endo Kenji
Takagi Yasuji
Altman, III Franklin D.
Frishauf, Holtz Goodman, Langer & Chick, P.C.
NHK Spring Co. Ltd.
Ometz David L.
LandOfFree
Suspension for supporting magnetic head does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Suspension for supporting magnetic head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Suspension for supporting magnetic head will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2618481