Ramp for information recording disk apparatus

Details Ramp for information recording disk apparatus Ramp for information recording disk apparatus

2000-11-09

2002-11-26

Cao, Allen (Department: 2652)

Dynamic magnetic information storage or retrieval

Head mounting

For moving head into/out of transducing position

Reexamination Certificate

active

06487051

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to the structure of a ramp, which retracts a suspension arm, which holds magnetic heads for reading or writing information from or to a recording disk of an information recording disk apparatus being rotated at high speeds, from the recording disk when the disk is not operated and then holds the retracted suspension arm.
2. Description of the Related Art
In information recording apparatuses employed in information processors such as computers or the like, the hard disk apparatus is an information recording disk apparatus employing a magnetic recording disk, which rotates at high speeds, as a recording medium. The hard disk apparatus rotates a plurality of magnetic recording disks (hereinafter stated as “recording disks”) at high speeds and reads and writes information by magnetic heads provided to correspond to the upper and lower surfaces of each recording disk.
The magnetic head used in the hard disk apparatus is supported by a suspension arm that is driven by an actuator, and moves over the recording disk at high speeds. Unless the magnetic head crashes, it never touches the recording disk, and the high rotational speed of the recording disk creates a thin cushion of air that floats the magnetic head off the disk by a very small amount.
The magnetic head is required not to contact the recording disk even when the disk does not rotate. This is because there is a possibility that the magnetic head will be fixedly attached on the surface of the recording disk, if the magnetic head contacts the disk for a long period of time when the disk is not rotating. If the magnetic head is fixedly attached on the disk surface, the start of rotation of the recording disk will separate the fixedly attached portion from the disk surface and destroy the disk surface.
The magnetic head is also required not to contact the recording disk even for such a short time that the magnetic head is not fixedly attached on the disk surface. For example, in the case where the magnetic head is contacted with the recording disk not being rotated, there is a possibility that the disk surface will be shaved due to friction which occurs when the magnetic head contacts the disk, during the time that the disk starts rotating and reaches a predetermined rotational speed. Generally, in order to float the magnetic head off the recording disk, the disk is required to have reached the predetermined rotational speed.
As described above, it is necessary that the magnetic head remains retracted from the recording disk until the disk reaches the predetermined rotational speed. For this reason, a magnetic-head holding mechanism called a ramp is recently known. The ramp is used to retract the magnetic head and the suspension arm from the recording disk and hold the retracted magnetic head, when the recording disk is less than the predetermined rotational speed.
The hard disk apparatuses in recent years are provided with a ramp that functions as a saving place for holding the magnetic head retracted from the recording disk during the stop of rotation of the disk and during low rotation. Such a hard disk apparatus unloads the magnetic head to the ramp if the rotational speed of the disk is reduced and becomes less than a rotational speed at which the magnetic head cannot float, and loads the magnetic head over the disk if the rotational speed of the disk rises and reaches an enough rotational speed to float the magnetic head. The method of unloading or loading the magnetic head from or to the ramp, as described above, is called a ramp loading method.
The ramp is molded and manufactured from high polymer material. The ramp is screwed to the housing of the hard disk apparatus and subjected to stress in the direction of compression in which it is pushed against the housing by the tightening torque of the screw. Therefore, if a long period of time passes, creep deformation which is plastic deformation will occur in the ramp formed from high polymer material.
In addition, the information recording disk apparatus has incorporated a motor, a driver circuit or the like to rotate the recording disk at high speeds, so it cannot be avoided that the temperature in the inside of the information recording disk apparatus will rise because of heat generated by the components. Therefore, the surrounding temperatures of the ramp also rise during high rotation of the recording disk and decrease and approach normal temperature during the stop of rotation of the recording disk. That is, the ramp is used under the condition that-temperature changes in a cycle. In that case, as also evident in the field of reliability tests that a temperature cycle accelerates time, for example, creep deformation is liable to occur with the passage of time.
FIG. 7
is a plan view showing a conventional magnetic recording disk apparatus employing the ramp. A magnetic recording disk apparatus
10
illustrated in
FIG. 7
houses recording disks
17
, a rotary actuator assembly
12
, a voice coil motor
16
, and a ramp
20
in the inside of a housing
11
and forms an airtight space in the inside. Each of the recording disks
17
has magnetic recording layers on the upper and lower surfaces and are stacked and fixedly attached to a spindle shaft
18
. Each disk is rotated integrally with the spindle shaft
18
by a spindle motor (not shown). The upper and lower surfaces of each of the recording disks
17
are used as the information recording surfaces, and a dedicated magnetic head (not shown) is employed with respect to each surface. The actuator assembly
12
has suspension arms
14
stacked by the same number as the information recording surfaces and is supported by a pivot shaft
13
. A slider
19
is attached to the front end of each suspension arm
14
and provided with magnetic heads that scan the upper and lower information recording surfaces of each disk. Furthermore, a lifting protrusion
15
is attached to the front end of the suspension arm
14
.
The actuator assembly
12
is rotated on the pivot shaft
13
by the voice coil motor
16
so that the slider
19
with the magnetic heads is loaded over the surface of the recording disk
17
or unloaded to the ramp
20
. The suspension arms
14
are formed from elastic material and urged in the direction in which each slider
19
attached to each suspension arm
14
approaches the corresponding disk surface of the recording disk
17
. If the force to float the slider
19
, created by rotation of the recording disk
17
, is balanced with the elastic force of the suspension arm
14
, the slider
19
will be floated a predetermined distance off the surface of the recording disk
17
being rotated. The ramp
20
is fixed to the housing
11
of the magnetic recording disk apparatus
10
by employing a screw
31
, at a position where the front ends of the ramp are near the recording disks
17
and alternately extend into between the disks without contacting any disks.
FIG. 8A
is a perspective view showing a conventional ramp where all parts have been molded en bloc by employing high polymer material containing polytetrafluoroethylene (PTFE), and
FIG. 8B
shows another conventional ramp reinforcing a screw hole with a metal sleeve in the ramp of FIG.
8
A. Note that
FIGS. 8A and 8B
show the ramps of the type that holds suspension arms in the case of stacking three double-sided recording disks.
As illustrated in
FIG. 8A
, the conventional ramp
20
is configured by an attaching portion
21
and an arm holding portion
22
. The attaching portion
21
has a screw hole
25
for fixing the ramp
20
to the housing
11
of the information recording disk apparatus
10
by employing a screw
31
. The arm holding portion
22
has storing portions
27
and guide portions
28
. Each of the storing portions
27
holds the slider
19
retracted from the corresponding recording disk
17
, the slider
19
having the magnetic heads for performing read and write operations on the recording disk
17
. Each guide portion
28
makes it easy for the suspensio

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