Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2001-04-12
2004-07-13
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S417000
Reexamination Certificate
active
06761543
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a linear compressor for compressing refrigerant by using a reciprocating piston. More particularly, the present invention relates to a piston operating assembly for the linear compressor and a method for manufacturing the same.
2. Description of the Prior Art
Generally, a linear compressor compresses a refrigerant by reciprocating a piston with a changing magnetic field. Such a compressor is shown in
FIGS. 1 through 3
.
As shown in the drawings, the linear compressor includes a cylinder portion
10
, a piston
20
, a piston operating assembly
30
and an external lamination portion
40
, all of which are disposed in a chamber
1
.
As shown in
FIG. 2
, the piston operating assembly
30
includes a magnet holder
32
, which is a hollow cylinder having a hole formed in an outer circumference thereof, a magnet
33
inserted in the hole of the magnet holder
32
, a magnet cover
35
press fit on the outer circumference of the magnet holder
32
to prevent any accidental separation of the magnet
33
from the magnet holder
32
, and a linking member
31
having a hole formed on the center portion thereof for receiving the piston
20
. The linking member
31
is connected to one end of the magnet holder
32
.
The piston
20
is a hollow cylinder, having one end attached to a suction valve
25
and the other end coupled to the linking member
31
of the piston operating assembly
30
. The piston
20
can be secured to the linking member
31
by one of a number of methods, such as welding, etc.
The cylinder portion
10
includes a cylinder
11
, in which the piston
20
is received for reciprocating movement, an internal lamination
13
inserted about the outer circumference of the cylinder
11
, and a coil
15
wound about the center portion of the internal lamination
13
.
An external lamination portion
40
includes an external lamination
41
formed a predetermined distance from the internal lamination
13
, a housing
43
for supporting the external lamination
41
, and a frame
42
.
The operation of the linear compressor constructed as above will be described below.
First, when Alternating Current (AC) voltage is applied to the coil
15
of the internal lamination
13
, a magnetic field having N-S poles is generated between the internal and external laminations
13
and
41
, respectively. Due to the presence of the permanent magnet
33
disposed between the internal and external laminations
13
and
41
, a force in an axial direction is generated according to Flemming's left-hand rule. As the N-S poles of the magnet
33
are varied, the magnet
33
reciprocates, and accordingly, the piston
20
also reciprocates.
Next, a refrigerant is introduced into the chamber
1
through an inlet tube
3
by the reciprocating movement of the piston
20
. The refrigerant flows through the piston
20
and the suction valve
25
and into a compressing chamber
5
. When the refrigerant is compressed in the compressing chamber
5
, the refrigerant is then discharged through an outlet tube
7
.
The conventional linear compressor, however, has several shortcomings. First, some parts of the compressor require forceful coupling methods, such as force fit, welding, etc., to secure the parts together. For example, the piston
20
and linking member
31
are welded together, as are the linking member
31
and the magnet holder
32
. Further, the magnet holder
32
must undergo processes like cutting, punching and welding. The force of the couplings and heat distortion of the respective parts produce an internal stress that affects the integrity of the parts. Further, the conventional linear compressor has a complex and lengthy assembly process, while producing a high possibility of defective products. As a result, productivity and throughput are deteriorated.
The manufacturing process of the magnet holder
32
is described in greater detail with reference to FIG.
3
. First, a metal plate
32
a
of a predetermined size is prepared. Then, the metal plate
32
a
undergoes a rolling process. Next, the ends of the metal plate
32
a
are welded together to form a hollow cylinder
32
b
. The hollow cylinder
32
b
is then punched to form a plurality of holes
32
c
therein. Finally, in order to prevent any accidental separation of the magnets
33
from the hollow cylinder
32
b
, a magnet cover
35
is force fit onto the outer circumference of the hollow cylinder
32
b.
In the conventional linear compressor, the different sizes of and deviations among the magnets
33
make it difficult to press fit or force fit the magnet cover
35
. When the magnet cover
35
is forcefully press fit, without taking into consideration the different sizes of the magnets
33
, those magnets
33
that are more fragile can be broken.
Further, according to a conventional way of assembling the piston operating assembly
30
of the linear compressor, an error in concentricity occurs when the piston
20
and the magnet holder
32
are welded to the linking member
31
, and errors in circularity and concentricity occur when press fitting the magnet
33
, which is press fit in the magnet holder
32
, in the magnet cover
35
. Accordingly, productivity and throughput deteriorate. Further, since there are numerous parts that must be assembled together, all of which affect the geometric tolerance of the piston operating assembly
30
, the assembly tolerance is increased due to an accumulation of the tolerances of the respective parts. When the geometric tolerance and the assembly tolerance exceed a predetermined degree, the same becomes a defect factor, which can cause problems, such as a malfunction of the linear compressor, etc.
In addition, in the conventional method of assembling the linear compressor, a non-magnetic metal is used to form the magnet holder
32
, thereby preventing a leakage of the magnetic force from the magnet
33
. The non-magnetic metal of the conventional linear compressor, however, has a relatively higher conductivity, which hinders a complete absence of the magnetic force leakage from the magnet
33
. Accordingly, due to the leakage of the magnetic force from the magnet
33
, the compression efficiency of the linear compressor is negatively affected.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the above-mentioned problems of the prior art. Accordingly, it is an object of the present invention to provide a piston operating assembly for a linear compressor having a piston coupling boss coupled with a piston, a plurality of magnets, and a linking member. The linking member connects the piston coupling boss with the magnets, all of which are integrally secured to the linking member when the linking member is injection molded. Thus, the integrated piston operating assembly has improved geometric and assembling tolerances and no deterioration of persistence.
It is another object of the present invention to provide a method for manufacturing a piston operating assembly for a linear compressor. In the present method the processes are simplified while resulting in a higher productivity.
The above object is accomplished by a piston operating assembly of a linear compressor for compressing a refrigerant with a piston that linearly reciprocates due to a magnetic field. The piston operating assembly includes a piston coupling boss for coupling to the piston, a plurality of magnets disposed in a cylindrical arrangement concentric with respect to the piston coupling boss, and a linking member for connecting and thus integrating the piston coupling boss and the plurality of magnets. The linking member is formed of an injection molded resin, and the piston coupling boss and the magnets are coupled to the linking member at the same time that the linking member is injection molded.
Each of the magnets has a stepped portion that is formed along a boundary thereof.
The above object is also accomplished by a method for manufacturing a piston operating assembly for a linear compressor. The method includes the s
Choi Kyung-shik
Jo Chal-gi
Freay Charles G.
Rodriguez William H.
Samsung Kwangju Electronics,Co., Ltd.
Westman Champlin & Kelly P.A.
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