Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-05-28
2004-10-19
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S180000, C310S181000, C310S184000, C310S160000, C310S168000
Reexamination Certificate
active
06806609
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a single phase induction motor, and more particularly, to a single phase induction motor having a centralized winding structure for use with a hermetic reciprocal compressor.
2. Description of the Related Art
A hermetic reciprocal compressor, as shown in
FIG. 1
, includes a sealed casing
10
, an electronic device unit
20
formed in the sealed casing
10
to serve as a driving source, and a compression device unit
30
for compressing refrigerant with linear reciprocal movement by the driving force of the electronic device unit
20
.
The electronic device unit
20
has a single-phase induction motor. The rotational driving force of the electronic device unit
20
is converted into the linear reciprocal movement of the compression device unit
30
by a crank device that has an eccentric shaft
31
and a connecting rod
32
. The compression device unit
30
has a cylinder block
33
and a piston
35
that slides longitudinally within a bore of the cylinder block
33
. One end of the piston
35
is connected to a connecting rod
32
such that the piston
35
is reciprocated within the bore of the cylinder block
33
in a linear direction in association with the rotational driving of the eccentric shaft
31
, to thereby draw and compress the refrigerant.
The single-phase induction motor has a stator and a rotor that is rotated by the revolving magnetic field of the electric force generated between the stator and the rotor. On the stator, a main winding and a sub winding are wound around a polar axis of an electric angle 90°.
When alternating current (AC) power is supplied to the main winding and the sub winding from a power source (not shown), the sub winding, which is positioned ahead of the main winding by the electrical angle of 90°, is first subjected to the rotational force caused by the revolving magnetic field generated by the electric current. Since the current phase of the sub winding is ahead of the current phase of the main winding due to a capacitor connected in series with the sub winding, the rotor is caused to rotate at a high speed.
FIG. 2
is an exploded perspective view of the single-phase induction motor used in a conventional compressor, and
FIG. 3
is a longitudinal sectional view of the single-phase induction motor of
FIG. 2
being assembled, in which reference numeral
21
denotes the stator,
22
the rotor, and
23
and
24
the main winding and the sub winding, respectively.
As shown in
FIGS. 2 and 3
, twenty-four (24) stator slots
21
a
are formed along an inner circumference of the stator in a manner such that the slots
21
a
are spaced from each other by a predetermined distance. A plurality of rotor slots
22
a
are also formed in the rotor
22
at a predetermined distance from each other. The main winding
23
and the sub winding
24
are wound through the stator slots
21
a
, while there also is a winding or a permanent magnet (not shown) wound through or inserted into the rotor slots
22
a.
FIG. 4
illustrates an order by which the main winding
23
and the sub winding
24
are wound through the twenty-four stator slots
21
a
of the conventional single phase induction motor. As illustrated, the conventional single phase induction motor has the winding structure of a distributed winding—so called concentric winding for the main winding
23
and the sub winding
24
.
In the distributed winding, the main winding
23
enters into the fourteenth slot (14th), and passes through the eleventh (11th), fifteenth (15th), tenth (10th), sixteenth (16th), ninth (9th), seventeenth (17th), eighth (8th), eighteenth (18th) and seventh (7th) slots and then re-enters into the twenty-third (23rd) slot, before passing through the second (2nd), twenty-second (22nd), third (3rd), twenty-first (21st), fourth (4th), twentieth (20th), fifth (5th), nineteenth (19th), and sixth (6th) slots, and then is drawn out. The sub winding
24
enters into the twelfth slot (12th), and passes through the first (1st), eleventh (11th), second (2nd), tenth (10th), third (3rd), ninth (9th), and fourth (4th) slots, and then re-enters into the thirteenth (13th) slot, before passing through the twenty-fourth (24th), fourteenth (14th), twenty-third (23rd), fifteenth (15th), twenty-second (22nd), sixteenth (16th), and twenty-first (21st) slots and then is drawn out.
In the conventional single phase induction motor, the main winding
23
and the sub winding
24
of the stator
21
are concentrically wound through the slots in an outward or inward direction, inevitably requiring an increased length of the coil end and subsequent cost increases and excessive use of copper.
In addition to the problem of increased length of the coil end due to the distributed winding structure of the main winding
23
and the sub winding
24
, the conventional single phase induction motor also has a problem caused due to the structure in which the winding protrudes from opposing sides of the stator
21
. That is, since the winding protrudes from the opposite sides of the stator
21
, additional processes like forming, lacing and cleaning are required for the purpose of tidying up the winding, and as a result,productivity deteriorates due to the increased manufacturing processes and other resulting difficulties.
Further, since the main winding
23
and the sub winding
24
each protrude from opposite sides of the stator
21
, the size of compressor inevitably unnecessarily increases.
SUMMARY OF THE INVENTION
The present invention overcomes the above-mentioned problems of the prior art. Accordingly, it is an object of the present invention to provide a single-phase induction motor having a shortened coil end, which is achieved by a centralized winding structure in which a main winding and a sub winding are wound through slots adjacent to each other, and is thus capable of reducing material costs and excessive use of copper.
Yet another object of the present invention is to provide a single-phase induction motor having a centralized winding structure in which the main winding and the sub winding are directly wound through slots adjacent to each other, requiring no separate processes like forming, lacing and cleaning for tidying up a protruded winding because the winding does not protrude, and is thus easy to manufacture.
Yet another object of the present invention is to provide a hermetic reciprocal compressor, which is smaller due to the compact-size of the single-phase induction motor.
The above objects are accomplished by a single-phase induction motor according to the present invention, including a stator having a plurality of slots; a rotor rotated by a magnetic field generated by an electric force between the stator and the rotor; and a main winding and a sub winding wound through the plurality of slots of the stator to form a revolving magnetic field on the rotor. The main winding and the sub winding form a centralized type of winding structure so that the main winding and the sub winding are wound in an alternate pattern via adjacent slots according to a certain rule which will be further described.
Since the main winding and the sub winding are wound through the slots of the stator in this centralized winding structure, the coil end length is greatly reduced, and as a result, the material costs and copper loss can also be reduced greatly.
Further, according to the present invention, the main winding and the sub winding, are wound through the slots of the stator, and do not protrude from opposite sides of the stator too much. Accordingly, processes like forming, lacing and cleaning to tidy up the protruded portion of the main winding and the sub winding, can be omitted, and therefore, the manufacturing process becomes simplified.
According to the preferred embodiment of the present invention, the stator has sixteen slots, and the main winding is inserted into slot (
1
a
) of the stator, then passed consecutively through slots (
2
b
), (
4
f
), (
3
e
), (
5
i
), (
6
j
), (
8
n
), (
7
m
), and then drawn out, wh
Aguirrechea J.
Ladas & Parry
Mullins Burton S.
Samsung Gwangju Electronics Co. Ltd.
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