Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2003-06-19
2004-07-13
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S0400MM, C310S267000, C310S090000, C384S453000
Reexamination Certificate
active
06762527
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to motors, and particularly to a DC brushless motor with strong structure so that rotary shaft of the rotor can be firmly secured.
BACKGROUND OF THE INVENTION
In the prior art, the DC (direct current) brushless motor is vertically arranged. Referring to
FIG. 1
, a prior art brushless motor is illustrated, where the motor includes a stator
10
, a rotary shaft
21
, cover
13
, a casing
14
having a ventilating groove
140
, and a fan
3
. The stator
30
is formed by silicon steel sheets
11
and coils which are disposed in the cover
13
. The rotor
20
is formed by a rotary shaft
21
, a disk magnet
23
and an enhancing plate
25
having ventilating grooves
24
,
26
. The cover
13
has a groove seat
330
. The seat has an axial hole. A bearing
15
is installed in the groove for assembling the rotary shaft
41
. The casing
14
has a bearing
15
for locating the rotary shaft
21
. The fan
3
is installed to the casing
14
at an upper end of the rotary shaft
21
. However, above mentioned prior art has the following defects.
Only one bearing
15
is used to combine the rotary shaft
21
of the rotor
20
to the cover
13
, so that ail the weight of the rotary shaft
21
is applied to the bearing
15
. Thus the lifetime of the bearing is short and thus the bearing
15
is updated frequently. Moreover, the rotary shaft
21
easily shifts so as to generate noise.
Moreover, the enhancing plate
25
of the rotor
20
is combined to the magnet
23
in a plane configuration by glue agent. If the glue agent is deteriorated, the combination will become loose. Furthermore, the fan is made by plastically injection molding and then the fan is locked to the rotary shaft
21
. Since plastic is soft, as the fan rotates with a higher speed, a large noise generates. Moreover, a gap is formed between the fan
3
the magnet
23
and the enhancing plate
25
. No vortex generates on the enhancing plate
25
. As a result, the air ventilation is low and heat dissipating is not preferred.
SUMMARY OF THE INVENTION
Accordingly, the primary object of the present invention is to provide a DC brushless motor which comprises a stator; a casing; a rotor formed by an enhancing plate, a magnet and a rotary shaft. The magnet and the enhancing plate are locked by studs other than using glue agent. A block on the lower surface of the enhancing plate is embedded into a central hole of the magnet so as to support the magnet and cause that the rotary shaft will not contact the magnet directly. A cover is extended with an inner sleeve. A groove seat is installed with a lower bearing and the inner sleeve is installed with a middle bearing and an upper bearing. The bearings are installed with respective enhancing pads. The rotary shaft of the rotor is installed with an annular enhancing flange and an annular inner flange which resist against the upper bearing. The inner flange resists against the enhancing pads of the middle bearing.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.
REFERENCES:
patent: 2436768 (1948-02-01), Arnold et al.
patent: 3484635 (1969-12-01), MacKallor
patent: 4060745 (1977-11-01), Linscott, Jr.
patent: 4211963 (1980-07-01), Muller
patent: 4260920 (1981-04-01), Nakamura et al.
patent: 4902923 (1990-02-01), Okauchi
patent: 5436518 (1995-07-01), Kawai
patent: 6347929 (2002-02-01), Cooper et al.
Comas Yahveh
Mullins Burton S.
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