Positioning device for prestressing magnet of spindle motor

Details Positioning device for prestressing magnet of spindle motor Positioning device for prestressing magnet of spindle motor

2002-11-27

2004-03-02

Ponomarenko, Nicholas (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S090500, C360S099080, C360S099070, C360S099040

Reexamination Certificate

active

06700241

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a positioning device for a prestressing magnet of a spindle motor and more particularly to the positioning device having an adjustable positioning member to thereby adjust a position of the prestressing magnet for balancing the spindle motor during rotation.
2. Description of the Related Art
Referring to
FIG. 1
, a conventional spindle motor
1
comprises a stator
10
, a prestressing magnet
11
, a bearing
12
, a rotor
20
, and a metal casing
21
. The prestressing magnet
11
is attached to the stator
10
by adhesive while the bearing
12
is inserted into the rotor
20
. A shaft
22
of the rotor
20
extends through the bearing
12
of the stator
10
to form the spindle motor
1
. Axially aligned with the metal casing
21
of the rotor
20
, the prestressing magnet
11
provides an axial magnet force to thereby cause balanced rotation of the rotor
20
. Consequently, a gap width (a) formed between the prestressing magnet
11
and the metal casing
21
is inversely proportional to the magnetic force therebetween.
Referring to
FIG. 2
, another conventional spindle motor
1
comprises a stator
10
, a prestressing magnet
11
, a bearing
12
, a rotor
20
, and a metal casing
21
. Formed with a neck portion
121
at its end, the bearing
12
is inserted into the stator
10
. The prestressing magnet
11
is attached to the neck portion
121
of the bearing
12
to form a unit. A shaft
22
of the rotor
20
extends through the bearing
12
of the stator
10
to form the spindle motor
1
. Axially aligned with the metal casing
21
of the rotor
20
, the prestressing magnet
11
provides an axial magnetic force to thereby maintain the rotor
20
in balanced rotation. Consequently, a gap width (a′) formed between the prestressing magnet
11
and the metal casing
21
is inversely proportional to the magnetic force therebetween.
Because the gap widths (a and a′) formed between the prestressing magnet
11
and the metal casing
21
are fixed, the axially magnetic force therebetween cannot be adjustable. In other words, the magnetic force generated between the prestressing magnet
11
and the metal casing
21
cannot be increased or decreased according to product features. In order to adjust the magnetic force, an appropriate position of the prestressing magnet
11
on the stator
10
must be changed.
The present invention intends to provide a positioning device for a prestressing magnet of a spindle motor having an adjustable positioning member adapted to adjust a distance with respect to a rotor in such a way to mitigate and overcome the above problem.
SUMMARY OF THE INVENTION
The primary objective of this invention is to provide a positioning device for a prestressing magnet of a spindle motor having an adjustable positioning member fittingly combined with a stator to thereby adjust a distance of a position of the prestressing magnet with respect to a rotor.
The positioning device for a prestressing magnet of a spindle motor in accordance with the present invention mainly comprises a stator, a positioning member, a prestressing magnet, a rotor and a metal casing. Combined with the prestressing magnet, the positioning member is fittingly secured to a predetermined position on the stator while the metal casing is secured to the rotor. After combining the stator with the rotor, the prestressing magnet is axially aligned with the metal casing. An axial magnetic force generated between the prestressing magnet and the metal casing maintains balanced rotation of the rotor.
Another aspect of the present invention is that the positioning member is fittingly pressed to secure to a predetermined positioned formed on an outer circumference of a neck portion of a bearing or the stator.
Another aspect of the present invention is that the positioning member is fittingly pressed to secure to a predetermined position formed on an outer circumference of an axial tube.


REFERENCES:
patent: 5994803 (1999-11-01), Jung
patent: 6300695 (2001-10-01), Neal
patent: 6340854 (2002-01-01), Jeong
patent: 6455961 (2002-09-01), Higuchi

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