Pumps – Inertia-type pumping member or drive means
Reexamination Certificate
2002-01-04
2004-05-11
Look, Edward K. (Department: 3746)
Pumps
Inertia-type pumping member or drive means
C417S415000, C417S416000, C417S417000
Reexamination Certificate
active
06733245
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a piston support structure of a reciprocating compressor, and more particularly, to a piston support structure of a reciprocating compressor which is positioned on both sides of a piston for receiving the linear reciprocating driving power of a reciprocating motor and compressing a gas while being in a linear reciprocating motion in the compression space of a cylinder. The piston support structure extends the durability of a resonant spring for elastically supporting the piston.
2. Description of the Background Art
In general, compressors for compressing fluid can be divided into rotary compressors, scroll compressors, and reciprocating compressors according to the respective method for compressing a refrigerant gas.
As shown in
FIG. 1
, an example of a reciprocating compressor includes a container
10
and a reciprocating motor
20
for generating linear reciprocating power loaded in the container
10
. The compressor also includes a hind frame
30
and a central frame
40
for supporting both sides of the motor
20
, a front frame
50
continuously combined with the central frame
40
, a cylinder
60
fixedly combined with the front frame
50
so as to be separated from the reciprocating motor by a predetermined distance, and a piston
70
connected to the reciprocating motor
20
and inserted into the cylinder
60
to be in a linear reciprocating motion in the cylinder
60
. The piston
70
also receives the linear reciprocating driving power of the reciprocating motor
20
. The compressor also includes a valve unit
80
combined with the cylinder
60
and the piston
70
. The valve unit
80
draws up a gas into the cylinder
60
and discharges the gas into the outside of the cylinder
60
due to the pressure difference generated by the reciprocation motion of the piston. A resonant spring unit
90
for elastically supporting the linear reciprocating motions of the reciprocating motor
20
and the piston
70
is also provided.
The reciprocating motor
20
includes a cylindrical outer stator
21
fixedly combined with the hind frame
30
and the central frame
40
, an inner stator
22
inserted into the outer stator
21
to be separated from the outer stator
21
by a predetermined distance, a winding coil
23
combined with the outer stator
21
inside the outer stator
21
, and a moving magnet A inserted between the outer stator
21
and the inner stator
22
to be in the linear reciprocating motion.
The moving magnet A includes a cylindrical magnet holder
24
and a plurality of permanent magnets
25
combined with the magnet holder
24
and separated from each other by a predetermined distance. The magnet holder
24
is connected to one side of the piston
70
.
The valve unit
80
includes a discharge cover
81
for covering the compression space P of the cylinder
60
and a discharge valve
82
located in the discharge cover
81
. The discharge valve
82
opens and closes the compression space P of the cylinder
60
. The valve unit
80
also includes a valve spring
83
for elastically supporting the discharge valve
82
and a suction valve
84
combined with the end of the piston
70
. The suction valve
84
opens and closes a suction channel F formed in the piston
70
.
The refrigerant gas is drawn up into a suction pipe
1
. The compressed refrigerant gas is discharged into a discharge pipe
2
. The operation of the conventional reciprocating compressor will now be described in greater detail hereinafter.
When power is supplied to the reciprocating motor
20
, current flows through the winding coil
23
. The moving magnet A, including the permanent magnets
25
, is in a linear reciprocating motion due to a mutual operation between the flux formed in the outer stator
21
and the inner stator
22
and the permanent magnets
25
due to the current that flows through the winding coil
23
.
The linear reciprocating driving power of the moving magnet A is transmitted to the piston
70
. Accordingly, the piston
70
has a linear reciprocating motion with a stroke that is the distance between a top dead center and a bottom dead center in the compression space P formed in the cylinder
60
. The valve unit
80
operates at the same time as the piston
70
. Accordingly, the refrigerant gas is sucked up into the compression space P of the cylinder
60
, is compressed, and is discharged into the outside of the cylinder
60
. The above processes are repeated.
The resonant spring unit
90
stores the linear reciprocating motion energy of the reciprocating motor
20
as elastic energy and emits the elastic energy. At the same time, the resonant spring unit
90
causes a resonant motion.
As shown in
FIG. 2
, the resonant spring unit
90
, which causes the resonant motion with respect to the linear reciprocating motion of a driving portion including the moving magnet A of the reciprocating motor
20
and the piston
70
combined with the moving magnet A, is combined with one side of the piston
70
. A spring supporter
91
formed to be bent so as to have a predetermined area is positioned between the front frame
50
and the central frame
40
.
A first resonant spring
92
is inserted between the front frame
50
and the spring supporter
91
. A second resonant spring
93
is inserted and combined between the spring supporter
91
and the central frame
40
.
The elastic modulus of the first resonant spring
92
is the same as the elastic modulus of the second resonant spring
93
. The first resonant spring
92
is combined with the second resonant spring
93
in a state where the first resonant spring
92
and the second resonant spring
93
are compressed to uniform lengths, respectively.
The first resonant spring
92
and the second resonant spring
93
are combined with each other so that the initial position f of the end of the piston
70
is moved from the center c between the maximum top dead center b and the maximum bottom dead center a toward the end d of the cylinder
60
by a predetermined distance, e.g., a movement distance e, considering gas spring force during compression.
Also, in the resonant spring unit
90
, when the piston
70
moves toward the top dead center, the first resonant spring
92
contracts and the second resonant spring
93
is extended to be longer than the initial setting length. When the piston
70
moves toward the bottom dead center, the first resonant spring
92
is extended to be longer than the initial setting length and the second resonant spring contracts. The moving magnet A and the piston
70
are elastically supported by repeating the above processes.
However, according to the conventional reciprocating compressor, during the process of compressing the refrigerant gas with the reciprocating motion of the piston
70
in the compression space P in the cylinder
60
, the gas spring force due to the increase in the pressure of the refrigerant gas compressed in the compression space P of the cylinder
60
is applied to the piston
70
. Accordingly, since the end of the piston
70
is in the linear reciprocating motion between the top dead center and the bottom dead center in a state where the end of the piston
70
is moved from the initial position f positioned during setting toward the center position c of the maximum top dead center b and the maximum bottom dead center a, the compressing displacement of the second resonant spring
93
is larger than the compressing displacement of the first resonant spring
92
.
Accordingly, the first resonant spring
92
receives less stress than the set stress, and the second resonant spring
93
receives more significant stress than the set stress. Therefore, the fatigue endurance of the second resonant spring
93
deteriorates to shorten the durability of the second resonant spring
93
.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a piston support structure for a reciprocating compressor which is positioned on both sides of a piston for receiving the linear reciprocating drivin
Bae Gyoo Jong
Lee Hyuk
Oh Won Sik
Birch & Stewart Kolasch & Birch, LLP
LG Electronics Inc.
Look Edward K.
Solak Timothy P.
LandOfFree
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