Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-06-06
2002-05-28
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S052000, C310S156260
Reexamination Certificate
active
06396190
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a washing machine, and more particularly, to a brushless motor for driving an inner tub or a pulsator in a washing machine.
2. Background of the Related Art
In general, the washing machine washes contaminated laundry clean by driving the inner tub or the pulsator by using a motor to circulate washing water having detergent contained therein.
FIG. 1
illustrates key parts of a related art full automatic washing machine, provided with an inner tub
1
, an outer tub
2
, and a shaft
5
having one end connected both to the pulsator
3
fitted inside of the inner tub
1
and the inner tub
1
and the other end having serration
5
a
connected to a brushless motor
4
. The brushless motor
4
designed to make regular and reverse rotation for driving the inner tub
1
and the pulsator
3
has a structure as shown in
FIGS. 2 and 3
.
That is, referring to
FIG. 2
, the brushless motor
4
is provided with a stator
10
having a coil
12
fitted to an upper frame
11
having a bearing
6
therein which is in turn fitted to the outer tub
2
, and a rotor
20
having a lower frame
21
fitted to an outer circumference of the stator for being rotated by a polarity difference. As shown in
FIG. 3
, there are a plurality of magnets
22
fitted along an inside circumference of the lower frame
21
in the rotor
20
at fixed intervals, and a back yoke
23
between the magnets and the lower frame for forming a magnetic path and supporting the magnets. There are a plurality of draft holes
24
in a bottom surface of the lower frame. And, there is a support member
30
having female serration
31
along an inside surface injection molded as a unit with, or bonded to the lower frame
21
for transmission of a rotating power from the rotor to the shaft
5
having the male serration and maintaining a gap between the upper frame
11
and the lower frame
21
.
The operation of the aforementioned system will be explained.
Upon application of a power to the brushless motor
4
, the rotor
20
of the motor rotates in one direction by a polarity difference from the stator
10
and a flow of magnetic flux along the back yoke
23
, to rotate the support member
30
coupled to the lower frame
21
of the rotor
20
. According to this, the shaft
5
coupled with the female serration
31
inside of the support member
30
receives the rotating force of the rotor
20
through the support member
30
to rotate the inner tub
1
coupled to the shaft
5
, thereby facilitating washing of the laundry.
However, the related art brushless motor has the following various problems caused by the structure.
First, the general plastic injection molded lower frame
21
in the rotor
20
of the related art brushless motor
4
impedes smooth dissipation of a heat generated during operation of the motor
4
to keep accumulation of the heat inside of the motor
4
, that causes thermal distortion of the lower frame
21
and various components, and degrades the performance rapidly and shortens a lifetime of the motor. Moreover, the many steps required for injection molding of the rotor
20
in fabrication of the brushless motor
4
takes much time period, which drops a productivity, and the reinforcement required for the rotor
20
increases a total weight.
Second, the requirement for a separate device, such as a jig(not shown), for fitting the magnets
22
to the related art lower frame
21
at fixed intervals leads to a complicated fabrication process. That is, the fastening of the magnets
22
to the jig and winding the back yoke
23
therearound for fitting the magnets
22
to the lower frame
21
requires many fabrication steps, that causes many defects, to increase a production cost.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a brushless motor in a washing machine that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a brushless motor in a washing machine, which can prevent an internal heating, for making a stable operation.
Another object of the present invention is to provide a brushless motor in a washing machine, which can simplify the steps of process for fitting the magnets to a rotor.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the brushless motor in a washing machine including a stator having a coil coupled to an upper frame, and a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed as one unit with, and at a central portion of the lower frame coupled to a washing water shaft for transmission of a rotating force of the lower frame to the washing water shaft.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 4631771 (1986-12-01), Anderson et al.
patent: 4712035 (1987-12-01), Forbes et al.
patent: 5266855 (1993-11-01), Smith et al.
patent: 5353613 (1994-10-01), Smith et al.
patent: 5528092 (1996-06-01), Ohta
patent: 5737944 (1998-04-01), Nishimura et al.
patent: 5778703 (1998-07-01), Imai et al.
patent: 6049930 (2000-04-01), Hisano et al.
Ahn In Geun
Bang Jong Chul
Lee Dong Beom
Fleshner & Kim LLP
LG Electronics Inc.
Mullins Burton S.
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