Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-09-02
2001-09-04
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S06700R, C310S194000, C310S216055
Reexamination Certificate
active
06285108
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a brushless DC motor to the structure of the stator of a brushless DC motor, the stator including a magnetic conductive tube and a pole plate.
2. Description of the Related Art
Referring to
FIG. 1
, a conventional brushless DC motor and stator comprises a metal tube
91
with outer surface surrounded by a coil
92
, an upper pole plate
93
, a lower pole plate
94
and a circuit board
95
. The upper plate
93
and the lower plate
94
are formed by a plurality of stacked silicon steel plates so as to increase the area adjacent to the permanent magnet of the rotor. Because it consists of a plurality of silicon steel plates the conventional motor and stator are complex, the cost of manufacture is high, and much more of the material.
Furthermore, one end of the metal tube
91
has an annular flange
911
which is larger than the diameter of the tube. When the other end of metal tube
91
being fixed, the annular flange
911
limits the coil
92
, the upper plate
93
, the lower plate
94
and the circuit board
95
, and thus the thickness of annular flange
911
increases the thickness of the stator. In order to decrease the thickness of the stator, the annular flange
911
may be removed for the best design.
Furthermore, U.S. Pat. No. 4,891,567, issued on Jan. 2, 1990 to Fujitani et al., discloses a pole plate having a pole which is bent in a right angle to the pole plate. The poles are bent toward each other, so that the poles cover the outer peripheral space of the coil seat. Thus, the pole plates are pressed and combined on the stator, after coils have been wounded on the coil seat of the stator. However, the poles of the stator are arranged to face each other because the coils must first be wounded on the coil seat of the stator, and then the pole plates pressed on the bobbin to form the stator. The pressing process of pole plates into a bobbin with a wound has the disadvantage that the coil wire may be cut or cut broken, the bobbin pressed, and the enameled layer of wires damaged. Wires of the coil suffer from starting current pulses in the long term resulting in the degrading of the coil assembly and resulting in deterioration of rotation of the motor and shortening motor life.
SUMMARY OF THE INVENTION
The primary object of this invention is to provide a stator of a brushless DC motor comprising a magnetic conductive tube, which has a pole plate on one end of the tube so as to reduce the thickness of the stator.
The secondary object of this invention is to provide a stator of a brushless DC motor comprising a magnetic conductive tube, which has a pole plate on one end of the tube, and another pole plate sleeved on the other end of the tube. At least one of the two pole plates has poles which extend in opposite directions to the poles of the other pole plate to form a larger conductive area of the pole plate so as to increase the torque of motor, and to permit freedom of design in accordance with the requirements of the motor without the limitation of space.
The third object of this invention is to provide a stator of a brushless DC motor comprising a magnetic conductive tube, which has a pole plate on one end of the tube, and another pole plate sleeved on the other end of the tube. At least one of the two pole plates has poles which extend in an opposite direction to those of the other pole plate to form a larger conductive area of the pole plate so as to reduce the thickness of pole plate, manufacture processes and the material cost of the pole plate.
The fourth object of this invention is to provide a stator of a brushless DC motor comprising a magnetic conductive tube whose outer surface may wind a coil or support a bobbin for a coil to simplify production processes and reduce the cost of manufacture.
The fifth object of this invention is to provide a stator of a brushless DC motor which has a thinner thickness that uses lesser material and reduces the processes of manufacture, in order to reduce the material and the manufacturing cost.
The sixth object of this invention is to provide a stator with a heat dissipating device which has a thinner thickness that uses lesser material and reduces the processes of manufacture, in order to reduce the material and the manufacturing cost.
In accordance with the present invention, a brushless DC motor comprises a magnetic conductive tube, which has a pole plate on one end of the tube and wound coils on the outer surface of the tube, and another pole plate is sleeved on the other end of the tube. The edge of both pole plates have poles extending in opposite directions to form a larger pole edge area to increase magnetic inductive area.
REFERENCES:
patent: 3551711 (1970-12-01), Davis
patent: 4891567 (1990-01-01), Fujitami et al.
patent: 5409352 (1995-04-01), Lin
patent: 5679997 (1997-10-01), Matsuzawa et al.
patent: 5917262 (1999-06-01), Huang et al.
patent: 0503123A1 (1992-09-01), None
Bacon & Thomas
Perez Guillermo
Ramirez Nestor
Sunonwealth Electric Machine Industry Co. Ltd.
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