Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
2001-03-16
2004-02-24
Watko, Julie Anne (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
C360S244600
Reexamination Certificate
active
06697227
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a head suspension for a disk drive incorporated in an information processing unit such as a personal computer and a method of manufacturing the suspension.
2. Description of the Related Art
A hard disk drive (HDD) used for an information processing unit has magnetic or magneto-optical disks to write and read data and a carriage. The carriage is turned around a spindle by a positioning motor.
The carriage is disclosed in, for example, U.S. Pat. No. 4,167,765. This carriage has arms, a head suspension (hereinafter referred to also as “suspension”) attached to each arm, and a head attached to the suspension. The head has a slider. When each disk of the HDD is rotated at high speed, the slider slightly floats above the disk and air bearings are formed between the disk and the slider.
The suspension consists of a load beam, a flexure, and a base plate. The load beam is made of a thin precision resilient plate. The flexure is made of a very thin plate spring fixed to a front end of the load beam by, for example, laser welding. The base plate is fixed to a base of the load beam by, for example, laser welding and is fixed to each arm of the carriage.
Disks of recent HDDs are designed to densely record data and revolve at high speed. It is required, therefore, to provide a head suspension of improved vibration characteristics to carry out precision positioning of a head on a disk surface, as well as resistance to turbulence caused by the disks revolving at high speed. In addition, the suspension must be ready for intricate processes to provide new functions.
To deal with a high-density disk, the suspension must have high rigidity and a low spring constant.
FIG. 1
shows a head suspension
101
for a disk drive according to a prior art. The suspension
101
has a load beam
103
that is solidly composed of a rigid part
103
a
of L
1
in length and a resilient part
103
b
of L
2
in length. It is hardly possible for this suspension
101
to simultaneously realize high rigidity for the rigid part
103
a
and a low spring constant for the resilient part
103
b
because the rigid part
103
a
and resilient part
103
b
are integrated with each other.
The material and thickness of the rigid part
103
a
are restricted by the resilient part
103
b
, and therefore, the rigid part
103
a
must improve the rigidity thereof by bends
105
or embossed ribs
107
that need additional precision processes to increase costs.
The bends
105
and ribs
107
disturb air flows and are easily influenced by turbulence due to disks rotating at high speed, to flutter the load beam
103
.
The load beam
103
is fixed to a base plate
109
, which is attached to a carriage arm of an HDD. To stably support the load beam
103
with the base plate
109
, the base of the load beam
103
must not be thinner than a specified thickness. This restriction prevents the lowering of the spring constant of the resilient part
103
b.
A flexure
111
is fixed to the load beam
103
. The flexure
111
has a head
113
including a slider
115
.
A technique of lowering the spring constant of a load beam is disclosed in Japanese Unexamined Patent Publication No. 9-191004. This technique partly thins a resilient part of a load beam by partial etching. The partial etching, however, has a limit in precisely controlling the thickness of the resilient part, and therefore, causes variations in the thickness and spring constant of the resilient part.
Japanese Unexamined Patent Publication No. 8-128919 discloses a technique of forming narrow plate springs around a slider supporting part of a load beam by etching or press. This technique deforms the narrow plate springs in a thickness direction, which needs fine processes because the narrow plate springs must be formed in a small area, to deform the shape of the load beam, vary the spring constant thereof, and deteriorate quality.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a head suspension of high performance to meet various requirements and method of manufacturing such a head suspension.
In order to accomplish the object, a first aspect of the present invention provides a head suspension for a disk drive, having a base plate to be attached to a carriage of the disk drive, and a load beam consisting of a rigid part and a resilient part, to apply load onto a slider. The rigid part and resilient part are separately formed, and the rigid part is joined to a first side of the resilient part. The suspension also has a reinforcing plate to hold and fix a second side of the resilient part between the reinforcing plate and the base plate.
The first aspect resiliently supports the load beam with the base plate through the resilient part. The material and thickness of the rigid part are not restricted by the resilient part because the first aspect separately forms the rigid part and resilient part with proper materials and thicknesses that meet their respective requirements to provide required performance for the suspension. For example, the rigid part is made of a thick plate to increase rigidity without bends or ribs and reduce air resistance. This results in reducing turbulence caused by the high-speed rotation of disks and preventing the fluttering of the suspension.
The first aspect stably holds the resilient part between the base plate and the reinforcing plate, so that the base plate may stably and resiliently support the rigid part through the resilient part. This three-layer structure of the base plate, resilient part, and reinforcing plate enables the resilient part to be thinned to secure a low spring constant. The low spring constant is also securable because the resilient part is formed independently of the rigid part. The first aspect simultaneously realizes stability, accuracy, and low spring constant for the resilient part.
The first aspect may form the rigid part from softer material than the resilient part. This expands the degree of freedom of the designing and processing of the rigid part.
A second aspect of the present invention provides the base plate with a boss protruding from the base plate in a thickness direction. The boss is fitted to a hole formed in the carriage, to fix the base plate to the carriage. The second aspect also provides each of the resilient part and reinforcing plate with a hole to receive the boss with at least one of the holes serving as a positioning hole that precisely fits the boss.
The second aspect correctly positions the load beam with respect to the base plate and sandwiches the resilient part between the base plate and the reinforcing plate. This results in stabilizing the manufacturing of the suspension.
A third aspect of the present invention makes each of the base plate and reinforcing plate thicker than the resilient part.
The third aspect firmly holds the resilient part between the base plate and the reinforcing plate and realizes a low spring constant.
A fourth aspect of the present invention provides a method of manufacturing a head suspension for a disk drive. The suspension has a base plate to be attached to a carriage of the disk drive, a load beam consisting of a rigid part and a resilient part, to apply load onto a slider, the rigid part and resilient part being separately formed, the rigid part being joined to a first side of the resilient part, and a reinforcing plate to hold and fix a second side of the resilient part between the reinforcing plate and the base plate. The method includes a first step of forming small holes in at least one of the base plate and reinforcing plate, and a second step of welding the base plate, resilient part, and reinforcing plate by emitting laser beams into the small holes, to fix the second side of the resilient part between the base plate and the reinforcing plate.
The fourth aspect welds the three-layer structure of the base plate, resilient part, and reinforcing plate together by emitting laser beams into the small holes. The use of the small holes saves laser power and surel
Kashima Hideki
Ohmoto Ryouzou
Ohtake Kazuhiko
Kilpatrick & Stockton LLP
NHK Spring Co. Ltd.
Watko Julie Anne
LandOfFree
Head suspension for disk drive and method of manufacturing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Head suspension for disk drive and method of manufacturing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Head suspension for disk drive and method of manufacturing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3294667