Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-01-10
2004-10-26
Le, Dang (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S254100, C310S049030
Reexamination Certificate
active
06809452
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a skeleton type brushless motor, and particularly, to a skeleton type brushless motor by which a leakage flux is small, and a maneuverability and an efficiency are increased.
2. Description of the Background Art
FIG. 1
is a partially longitudinal sectional view showing a conventional skeleton type brushless motor, and
FIGS. 2 and 3
are a side view and an enlarged view showing the conventional skeleton type brushless motor.
FIG. 4
is a side view showing a stator core in the conventional skeleton type brushless motor shown in
FIG. 1
, and
FIGS. 5 and 6
are a side view and a plan view showing a PCB (Printed Circuit Board) cover in the conventional skeleton type brushless motor shown in FIG.
1
.
As shown in
FIGS. 1
,
2
, and
3
, the conventional skeleton type brushless motor comprises: a rotor
111
, a stator
121
in which the rotor
111
is received with an air gap therebetween, a PCB
151
in which a drive control circuit (not shown) for rotating and controlling the rotor
111
is formed; and a PCB cover
153
which is coupled to one side of the stator
121
for receiving and supporting the PCB
151
.
The rotor
111
is made by a permanent magnet of cylindrical shape, and a rotational shaft
112
is fixed to a center of the rotor
111
so as to be rotatable as a single body with the rotor
111
.
As shown in
FIG. 4
, the stator
121
comprises: a stator core
123
on which a first rotor receiving part
125
a
and a second rotor receiving part
125
b
are formed as a single body, a bobbin
127
which is assembled to the stator core
123
, a coil
129
wound around the bobbin
127
and power is applied alternatively to each other.
The stator core
123
includes a first stator core
124
a
on which the first rotor receiving part
125
a
and the second rotor receiving part
125
b
which are disposed facing each other with the rotor
111
therebetween and generates magnetic poles alternatively with each other in accordance with a position of a magnetic pole on the rotor
111
are formed as a single body, and a second stator core
124
b
fixed to the first stator core
124
a
penetrating the bobbin
127
for forming a magnetic path.
The first stator core
124
a
and the second stator core
124
b
are made by laminating steel sheets and assembled as a single body with each other by rivet
131
. In addition, a pair of through holes
133
are formed on the first stator core
124
a
as penetrating the plate surface thereof.
A pair of detent parts
135
, which are symmetric with each other centering around the rotational shaft
112
of the rotor
111
, are formed on the respective first rotor receiving part
125
a
and the second rotor receiving part
125
b
so that the rotor
111
is not arranged on a position of zero torque for initial driving the rotor
111
.
The rotational shaft
112
of the rotor
111
is rotatably supported by a pair of bearings
137
, and a bearing housing
139
is coupled around the bearings
137
so as to receive and support the bearings
137
.
As shown in
FIGS. 1 and 3
, a bearing receiving part
141
is formed at center part of the bearing housing
139
so as to receive and support the bearing
137
, and an extended receiving part
143
is formed on one side of the bearing receiving part
141
so as to cover exposed part of the rotor
111
which is exposed from the stator core
123
along with the rotational shaft direction.
A screw boss
145
which is received and coupled to the through hole
133
of the first stator core
124
a
is formed on boundary part of the extended receiving part
143
so that the screw
147
can be coupled via the shaft center.
Meanwhile, as shown in
FIG. 5
, a sensor receiving part
155
is formed on a center line of the rotor
111
in length direction of the
FIG. 5
for receiving and supporting a position sensor (not shown) which detects a rotation position of the rotor
111
as having 90° of phase difference from a horizontal center line of the first and second rotor receiving parts
125
a
and
125
b.
However, in the conventional skeleton type brushless motor, the first rotor receiving part
125
a
and the second rotor receiving part
125
b
are formed as a single body with each other, and therefore a leakage flux may be generated through a connected part, and accordingly, an effective magnetic flux is reduced. Therefore, the efficiency of the motor is lowered.
Also, in case that an outer diameter of the rotor
111
is increased in order to increase an output, then a width and a length of the stator
121
should be increased for corresponding to the increased outer diameter of the rotor, and therefore the motor can not be constructed compactly.
In addition, the extended receiving part
143
is formed integrally with the conductive bearing housing
139
for receiving the exposed part of the rotor
111
exposed from the stator core
123
, and therefore, an eddy current loss may be generated by the extended receiving part
143
.
Also, if the detent part
135
is enlarged so as to get advantage for initial driving, the air gap is enlarged relatively, and therefore the efficiency of the motor is lowered and it is not easy to improve initial maneuverability.
In addition, the position sensor is disposed on a position of 90° from the horizontal center line of the first and second rotor receiving part
125
a
and
125
b
and detects the rotation position, and therefore a delaying occurs until peak value of applied current is reached due to inductance components, if the magnetic pole of the rotor
111
and the electric current is applied another coil, whereby the efficiency of the motor is lowered.
Also, a DC (Direct Current) electric source should be used in the conventional skeleton type brushless motor, and therefore an additional DC power supplying device must be needed, which results in a large volume and high cost.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a skeleton type brushless motor which is able to reduce a leakage flux and improve maneuverability and efficiency.
To achieve the object of the present invention, as embodied and broadly described herein, there is provided a skeleton type brushless motor comprising: a rotor in which a rotational shaft is fitted and fixed; a stator including a first stator core and a second stator core in which a rotor receiving part for receiving the rotor is formed respectively, a coil winding unit coupled to the stator cores, and a coil wound on the coil winding unit; and wherein the first and the second stator cores are separated electrically with each other and faces each other centering around the rotational shaft of the rotor.
Also, the rotor receiving part comprises a first rotor receiving part and a second rotor receiving part of semicircular shape. In addition, a first separate space and a second separate space are formed between both ends of the first rotor receiving part and both ends of the second rotor receiving part.
Also, outer surfaces around both ends of the first rotor receiving part and of the second rotor receiving part in the first and second stator cores are protrudingly formed outwardly in a radial direction of the rotor.
Also, a rotation position sensor for sensing a rotational position of the rotor is disposed around 10°~20° in opposite direction of the rotational direction of the rotor from the separate space nearer to the coil winding unit.
Also, the skeleton type brushless motor according to the present invention comprises a driving control unit coupled to the coil winding unit in the rotational shaft direction for driving and controlling the rotor, and the driving control unit includes a sensor receiving part so that the rotational position sensor can be received therein.
Also, the skeleton type brushless motor further comprises a pair of shaft support parts for supporting the rotational shaft of the rotor so as to be rotatable, and a pair of separating members between the stators for separating the stator and the shaft support
Cho Kwan Yeul
Han Seung Do
Kim Yoon Hyeo
Shin Hyoun Jeong
Hanh Nguyen N
LG Electronics Inc.
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