Lubrication – Systems – Rotary compressor
Reexamination Certificate
2000-08-25
2003-06-03
Fenstermacher, David (Department: 3682)
Lubrication
Systems
Rotary compressor
C417S211000, C417S415000
Reexamination Certificate
active
06571917
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a linear compressor, and more particularly, to a linear compressor having an oil supply structure suitable for a smooth lubricating operation, so as to prevent abrasion at a friction portion between a cylinder and a piston according to shortage of oil.
BACKGROUND ART
Generally, a linear compressor compresses a coolant gas by directly and reciprocally moving a piston by means of a magnet or a coil instead of a crank shaft, one example of which is as shown in
FIGS. 1 and 2
.
FIG. 1
is a vertical-sectional view of a general linear compressor in accordance with a conventional art, and
FIG. 2
is a vertical-sectional view of an oil supply structure of the linear compressor in accordance with the conventional art.
As shown in the drawings, the general linear compressor includes a compressive unit
40
installed in a well-closed container
1
having a predetermined form in the horizontal direction for sucking, compressing and discharging a coolant, and an oil supply unit
50
fixed at an outside of the compressive unit
40
for supplying oil toward inside the compressive unit
40
, especially, to the friction portion between a cylinder
3
and the piston
6
(to be described).
The compressive unit
40
includes a circular frame
1
; a cover
2
fixedly installed at one side of the frame
1
; a cylinder
3
fixedly installed at the center of the frame
1
in the horizontal direction; an inner lamination assembly
4
A fixedly installed at the outer circumfer00ential surface of the frame
1
which supports the cylinder
3
; an outer lamination assembly
4
B fixedly installed at the inner circumferential surface of the frame
1
, having a void with the inner lamination assembly
4
A, for forming an induction magnetic field together with the inner lamination assembly
4
A; a magnet assembly
5
insertedly positioned in the void between the inner lamination assembly
4
A and the outer lamination assembly
4
B, consisting of a magnet
5
a
and a magnet paddle
5
b
, and linearly and reciprocally moving by the induction magnetic field; a piston
6
integrally fixed at the magnet assembly
5
and linearly and reciprocally moving as being inserted into the cylinder
3
to suck and compress the coolant gas, the piston being elastically supported by the cover
2
; a suction valve
7
mounted at the front end face of the piston
6
; and a discharge cover
10
installed at the front end portion of the cylinder
3
and having a discharge valve assembly
11
inside thereof.
As shown in
FIG. 2
, oil inlet passage
1
a
communicated with the oil supply unit
50
is formed at the frame
1
in the hollow direction along the cylinder
3
. A first circular oil groove
1
b
is formed on the inner circumferential surface of the cylinder
3
, communicating with the oil inlet passage
1
a
. At least one oil through hole
3
a
for supplying oil to the friction portion with the piston
6
is formed at the cylinder
3
facing the first oil groove
1
b
. A second circular oil groove
6
b
is formed at the outer circumferential surface of the piston
6
, communicating with the oil through hole
3
a
. An oil communicating path
1
c
at the inner circumferential surface of the cylinder
3
at the side facing the oil inlet passage
1
a
, communicating with the first oil groove
1
b
. The oil communicating path
1
c
is communicated with a oil circulation path
1
d
formed at the end portion thereof when the frame
1
is combined to the cylinder
3
. An oil discharge hole
1
e
is formed at the lower side of the oil circulation path
1
d.
Meanwhile, the oil supply unit
50
includes an oil cylinder
21
attached on the bottom of the compressive unit
40
; an oil piston
22
inserted into the oil cylinder
21
to divide the cylinder to the suction space and a discharge space, and having an oil communicating hole
22
a
for communicating the suction space and the discharge space; a first and a second oil springs
23
A and
23
B for elastically supporting the both ends of the oil piston
22
against the oil cylinder
21
; a suction cover
24
and a discharge cover
25
for supporting each other end of the first and the second oil springs
23
A and
23
B and fixing the both ends of the oil cylinder
21
to the compressive unit
40
; an oil suction valve
26
supported by the first oil spring
23
A at the outlet side of the oil piston
22
; and an oil discharge valve
27
installed at the outlet side, of the oil cylinder
21
.
Reference numeral
4
b
denotes a coil assembly,
6
a
denotes a coolant passage,
8
denotes a main spring and
9
denotes a suction pipe.
The operation of the linear compressor constructed as described above will now be explained.
First, when an induction magnetic field is generated as current is applied to a stator of a linear motor consisting of the inner lamination assembly
4
A and the outer lamination assembly
4
B, the magnet assembly
5
, a rotor in the void between the inner lamination assembly
4
A and the outer lamination assembly
4
B linearly reciprocates owing to the induction magnetic field, so that the piston
6
moves reciprocally in the cylinder
3
. Due to the piston's reciprocal movement in the cylinder
3
, the coolant gas introduced into the well-closed container
30
is sucked into the compressed space ‘C’ of the cylinder through the coolant passage
6
a
formed at the center of the piston
6
. The compressed gas opens the discharge valve assembly
11
to be discharged to the outside from the discharge cover
10
. These processes are repeatedly performed.
In the above process, the oil supply unit
50
vibrates along with the compressive unit
40
, pumping the oil filling the bottom of the well-closed container
30
to supply it to the compressive unit
40
. The oil pumped from the oil supply unit
50
is induced to the first oil groove
1
b
through the oil inlet passage
1
a.
The oil induced to the first oil groove
1
b
fills the second oil groove
6
b
through the through hole
3
a
, cooling the cylinder
3
, and lubricates the friction portion between the cylinder
3
and the piston
6
.
Thereafter, after lubricating the friction portion between the cylinder
3
and the piston
6
, the oil is induced to the other first oil groove
1
b
through the other oil through hole
3
a
, cooling the discharge cover
10
along the oil communicating path
1
c
and the oil circulation path
1
d
together with the oil that filled the first oil groove
1
b
, and returns to the well-closed container
30
through the oil discharge hole
1
e.
However, the linear compressor of the conventional art as described above has problems in that since the oil inlet passage
1
a
of the frame and the oil through hole
3
a
of the cylinder
3
are linearly formed to the compressive unit
40
, when the compressor is stopped, the oil filling the first oil groove
1
b
of the frame
1
and the second oil groove
6
b
of the piston
6
flows out through the oil of inlet passage
1
a
, being taken out toward the oil supply unit
50
and the well-closed container
30
, resulting in that when the compressor is actuated again, friction occurs at the friction portion between the cylinder
3
and the piston
6
due to the oil shortage until the oil is re-supplied to the friction portion, and due to the friction, the piston or the cylinder may be abraded.
TECHNICAL TASK OF THE INVENTION
Accordingly, in order to overcome the problems of the conventional linear compressor, an object of the present invention is to provide a linear compressor having an oil backflow prevention device by which oil always exists at the friction portion between a cylinder and a piston so that even when a compressor is stopped and re-started, the friction portion is smoothly lubricated.
DISCLOSURE OF THE INVENTION
In order to accomplish the above object, there is provided a linear compressor including a well-closed container filled with oil at its bottom, a compressive unit having a frame of a hollow inside the well-closed container to which a cylinder inserted, a piston inserte
Fenstermacher David
LG Electronics Inc.
Ostrolenk Faber Gerb & Soffen, LLP
LandOfFree
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