Dynamic information storage or retrieval – Dynamic mechanism subsystem – Specific detail of storage medium support or motion production
Reexamination Certificate
2000-09-26
2004-03-09
Chen, Tianjie (Department: 2652)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Specific detail of storage medium support or motion production
C369S263100
Reexamination Certificate
active
06704272
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a spindle rotation driving device such as a spindle motor for rotating a plurality of information recording mediums stacked such as a hard disk, optical disk, optical card, and the like, an information recording/reproduction apparatus, and an information recording medium manufacturing method.
2. Related Background Art
An information recording/reproduction apparatus used in the manufacture, inspection, and the like of information recording mediums such as a hard disk, optical disk, optical card, and the like mounts a spindle rotation driving device such as a spindle motor or the like for rotating a plurality of disks which are stacked.
FIG. 6
shows a conventional spindle rotation driving device. A spindle portion
110
which stands upright on the surface of a base
101
of the information recording/reproduction apparatus holds a stack of a plurality of disks D, and is rotated by a motor M
0
disposed below the base
101
.
The spindle portion
110
has a shaft
112
which is rotatably supported by a pneumatic bearing
111
fixed to the base
101
. On the stationary side of the pneumatic bearing
111
, a ring-shaped air pad
111
a
made up of a porous material and a pipe
111
b
for guiding clean air thereto are provided.
The plurality of disks D are stacked to sandwich a spacer S between neighboring disks D, and are clamped between a clamp
112
a
integrated with the shaft
112
, and a hub
113
fastened to the upper end of the shaft
112
.
The shaft
112
extends below the base
101
via a flange
112
b
disposed under the pneumatic bearing
111
. A scale disk
115
of an encoder is mounted on the lower end of the shaft
112
and opposes an optical head
116
.
A rotor
117
made up of a magnet integrated with the shaft
112
, and a stator
119
consisting of a yoke
119
a
and coil
119
b
held by a motor housing
118
construct a motor which rotates the shaft
112
. Note that the encoder is used in detection, control, and the like of the rotational speed of the motor.
Each spacer S is inserted to maintain parallelness of the disks D, and to suppress surface run-out upon rotation.
Upon fitting the disks D on the shaft
112
, the central holes of the disks D are pressed against the shaft
112
alternately in opposing directions, so that the gaps formed between the shaft
112
and the central holes of the disks D are evenly distributed on the two sides of a rotation axis (spindle axis) O. In this way, dynamic unbalance caused by eccentricity of the disks D is suppressed.
Recently, an information recording apparatus is required to record large-size information, and therefore the recording densities and rotational speeds of recording mediums such as disks and the like are increasing. For this reason, smaller track pitches and strict management of track pitch errors are required. In order to meet such requirements, it is important to suppress not only synchronous and asynchronous vibrations but also eccentricity of each recording medium with respect to the spindle axis.
Compared to the required track pitch precision, the central hole of a disk as a recording medium has a very large hole diameter tolerance as standards, and eccentricity of a disk caused by this tolerance makes improvement in the track pitch precision difficult.
Any dynamic unbalance of the center of gravity upon rotating a disk causes whirling vibration, and vibrates not only the spindle axis but also a magnetic recording converter such as a magnetic head or the like via the base that fixes the motor at high rotational speed, thereby disturbing accurate alignment.
Furthermore, a stack of a large number of disks makes eccentricity correction of the disks harder, and enhances any already existing dynamic unbalance.
In the prior art, the surface run-out of each disk in the horizontal direction is suppressed using the spacer, but no mechanism for correcting any dynamic unbalance caused by eccentricity of each disk is added. For this reason, the disks are alternately pressed against the shaft to uniformly distribute gaps between the inner circumferential surfaces of the disks and the shaft, thus suppressing the dynamic unbalance. However, such measure maximizes the gap between each disk and the shaft, and the eccentricity amount of each disk becomes ½ the tolerance of the diameter of the central hole of the disk.
Upon building a system within a limited space, it is difficult for a single fluid bearing that rotatably supports the lower portion of the shaft to suppress vibrations of the distal end portion of the disk stack, as indicated by the broken line in FIG.
6
.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the problems that remain unsolved of the prior art, and has as its object to provide a spindle rotation driving device which suffers less whirling vibrations due to a dynamic unbalance upon rotating a stack of recording mediums such as disks and the like, an information recording/reproduction apparatus, and an information recording medium manufacturing method.
In order to achieve the above object, a spindle rotation driving apparatus of the present invention comprises a spindle portion having a shaft for holding a stack of recording mediums, a first fluid bearing for rotatably supporting the spindle portion, a motor for rotating the spindle portion, an aligning member which is pressed against an upper end portion of the shaft in an axial direction, and a second fluid bearing for maintaining the aligning member in a non-contact manner with respect to the upper end portion of the shaft.
Preferably, the aligning member is coupled to a floating plate which is free to float or be chucked on a lift stage by a fluid pressure.
Preferably, an air pad for injecting fluid is provided on a cylindrical surface of the shaft, and eccentricity of the recording mediums fitted on the shaft is prevented by a fluid film formed by the fluid.
Preferably, air of the second fluid bearing is supplied from the first fluid bearing via an inner pipe of the shaft.
Preferably, air of the air pad of the shaft is supplied from the first fluid bearing via an inner pipe of the shaft.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.
REFERENCES:
patent: 5760509 (1998-06-01), Chung
patent: 5855436 (1999-01-01), Eum et al.
patent: 5920443 (1999-07-01), Ekhoff
patent: 6023114 (2000-02-01), Mori et al.
patent: 6127756 (2000-10-01), Iwaki et al.
patent: 6137650 (2000-10-01), Heine et al.
patent: 6366552 (2002-04-01), Oldermann et al.
U.S. patent application Ser. No. 09/415,457 filed Oct. 14, 1999.
Canon Kabushiki Kaisha
Chen Tianjie
Fitzpatrick ,Cella, Harper & Scinto
LandOfFree
Spindle rotation driving device with aligning member and air... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spindle rotation driving device with aligning member and air..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spindle rotation driving device with aligning member and air... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3234429