Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
1997-12-03
2001-04-03
Letscher, George J. (Department: 2754)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06212043
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a damping material which is pasted on the head suspension of disk units and to a head suspension with the damping material.
2. Description of the Prior Art
The head for use in magnetic disk units such as a hard disk drive (HDD), a magneto optical drive and the like floats by keeping a minute space on a magnetic disk which is spinning at a high speed, thereby carrying out read/write of information on the disk. With the demand for high recording density in recent years, the head size and floating quantity have been minimized, so that, in order to effect read/write of information on the magnetic disk exactly, it is important to locate the head part precisely while suppressing its vibration.
As shown in
FIGS. 10A
to
10
C, the structure of a head suspension is generally constructed with a magnetic head
1
, a head supporting spring
2
which supports the head and a fixing block
3
which fixes the suspension.
Since the aforementioned head part receives vibration from, for example, a drive unit of the head
1
and a motor for use in the spin drive of disks, the head supporting spring
2
formed with a plate spring or the like is deformed and the position of the head
1
slips off, thus frequently causing errors in reading and writing. In consequence, in order to decrease or remove vibration in the head supporting spring
2
, a method has been proposed in which a damping material
4
prepared by laminating a constraining body and a visco-elastic body is pasted on the linear part of the head supporting spring
2
(Japanese Patent Publication No. Hei. 4-8868). According to this method, the visco-elastic body interposed between the vibrating head supporting spring
2
and the constraining body deforms accompanied by the vibration deformation of the head supporting spring
2
, thereby generating internal resistance (molecular friction) which converts the vibration energy into thermal energy, and thus exerting a damping effect in which the vibration energy the head suspension will directly receive is greatly reduced.
It is important that the constraining body has high rigidity in order to improve the just described damping effect, and a metal plate such as of stainless steel is generally used as the constraining body. Also, an adhesive, rubber or the like is used as the visco-elastic body.
However, since vibration absorption of the head suspension disclosed in Japanese Patent Publication No. Hei. 4-8868 is still insufficient, further improvement of the effect has been expected. Since the recent tendency toward multi-media performance demands high memory capacity, high memory density and high speed read/write, it becomes more and more important to precisely locate the head and head suspension parts while suppressing their vibration, in order to effect read/write of information on the magnetic disk exactly.
SUMMARY OF THE INVENTION
The present invention has been made taking such circumstances into consideration, and it contemplates providing a damping material which is light and inexpensive and has excellent damping effect and a head suspension in which the damping material is used.
In order to achieve the aforementioned object, the head suspension of the present invention has a construction in which a damaging material is mounted over the flat part to the curved part of the supporting arm of a head supporting spring of a disk unit, wherein rate of change in static spring constant of the head supporting spring mounted with the damping material is within 20% in comparison with the static spring constant of the unmounted head supporting spring.
In the above construction, it is desirable that the damping material is a laminate in which a constraining body having a rigidity (modulus of elasticity×thickness) of 100 kg/mm or less and a visco-elastic body made of an acrylic adhesive are pasted together.
Next, the damping material of the present invention is a damping material to be used in the just described head suspension, having a construction in which a constraining body having a rigidity (modulus of elasticity×thickness) of 100 kg/mm or less is laminated with a visco-elastic body made of an acrylic adhesive. The rigidity exceeding 100 kg/mm is not desirable, because the spring constant of the head suspension becomes too high.
In the above construction, it is desirable that the thickness of the acrylic adhesive layer is within the range of from 20 to 250 &mgr;m.
REFERENCES:
patent: 4819094 (1989-04-01), Oberg
patent: 5825590 (1998-10-01), Ohwe
Iida Hiroyuki
Nakamura Masao
Tatsumi Motoshige
Toyota Hidetsugu
Letscher George J.
Nitto Denko Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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