Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2002-01-14
2004-06-22
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C464S102000
Reexamination Certificate
active
06752606
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll compressor, and in particular to a rotation preventive device for a scroll compressor which is capable of preventing a rotation of a scroll compressor.
2. Description of the Background Art
Generally, a scroll compressor compresses a fluid such as air or refrigerant gas, etc. by orbiting in a state storing gas between two wraps having an involute shape.
As depicted in
FIG. 1
, the scroll compressor is constructed with a power generating part generating a driving force and a compressing mechanism part compressing gas by the driving force transmitted from the power generating part.
FIG. 1
is a longitudinal sectional view illustrating a compressing mechanism part of the conventional scroll compressor.
As depicted in
FIG. 1
, in the compressing mechanism part of the conventional scroll compressor, a fixed scroll
2
having an involute-shaped wrap
2
a
is combined with the upper surface of a frame
1
, and an orbiting scroll
3
having an involute-shaped wrap
3
a
engaging with the wrap
2
a
of the fixed scroll
2
is eccentrically combined between the frame
1
and the fixed scroll
2
so as to perform an orbiting motion.
A suction hole
2
b
at which a fluid is sucked is formed at the side of the fixed scroll
2
, and a discharge hole
2
c
is formed at the upper central portion of the fixed scroll
2
in order to discharge compressed gas.
A boss portion
3
d
projecting from the bottom surface of the orbiting scroll
3
is combined with an eccentricity portion
4
a
of a rotational shaft
4
rotated by a power generating part (not shown).
Particularly, a rotation preventive member
10
called as an oldham coupling is installed between the frame
1
and the orbiting scroll
3
in order to prevent a rotation of the orbiting scroll
3
.
In
FIG. 1
, unexplained reference numeral P
1
and P
2
indicate a compressive space formed between the wrap
2
a
of the fixed scroll
2
and the wrap
3
a
of the orbiting scroll
3
.
FIG. 2
is a disassembled perspective view illustrating a combination relation of the rotation preventive member in more detail.
In the rotation preventive member
10
, a first and a second keys
12
a
,
12
b
projecting from the upper surface of a ring body
11
as a rectangular shape are placed in a straight line, and a third and a fourth keys
12
c
,
12
d
projecting from the bottom surface of the ring body
11
as a rectangular shape are placed in a straight line at right angles to the straight line connecting the first and the second keys
12
a
,
12
b.
In order to insert the first and the second keys
12
a
,
12
b
and move them in a straight line, key grooves
3
b
,
3
c
are respectively formed at the bottom surface of the orbiting scroll
3
in a straight line.
In order to insert the third and the fourth keys
12
c
,
12
d
and move them in a straight line, key grooves
1
a
,
1
b
are respectively formed at the upper surface of the frame
1
in a straight line.
In addition, as depicted in
FIG. 1
, a through hole
1
c
at which the rotational shaft
4
penetrates through is formed at the central portion of the frame
1
, and a step portion
1
d
forming a thrust bearing face is formed around the through hole
1
c
in order to support rotatively the bottom surface of the orbiting scroll
3
.
Accordingly, when the rotation preventive member
10
is placed between the frame
1
and the orbiting scroll
3
, the first and the second keys
12
a
,
12
b
are respectively inserted into the key grooves
3
b
,
3
c
of the orbiting scroll
3
, and the third and the fourth keys
12
c
,
12
d
are respectively inserted into the key grooves
1
a
,
1
b
of the frame
1
.
The operation of the conventional scroll compressor will be described with reference to accompanying FIG.
3
.
When power is applied to the power generating part (not shown), a driving force generated by the power generating part is transmitted to the rotational shaft
4
, the orbiting scroll
3
orbits by engaging with the fixed scroll
2
by the rotation preventive member
10
, in the orbiting process, while the pair of compressing spaces (P
1
) (P
2
) are consecutively moved to the discharge hole
2
c
, a body capacity of the pair of compressing spaces (P
1
) (P
2
) existed between the wrap
2
a
of the fixed scroll
2
and the wrap
3
a
of the orbiting scroll
3
is gradually decreased, accordingly gas sucked through the suction hole
2
b
is discharged outside through the discharge hole
2
c.
In more detail, the orbiting scroll
3
tends to rotate eccentrically together with the rotational shaft
4
, however because each key
12
a
,
12
b
,
12
c
,
12
d
of the rotation preventive member
10
is inserted into each key groove
3
b
,
3
c
of the orbiting scroll
3
and
1
a
,
1
b
of the frame
1
slidable only in a radial direction, the side of each key
12
a
,
12
b
,
12
c
,
12
d
contacts to the correspondence face of each key groove
3
b
,
3
c
,
1
a
,
1
b
, accordingly it is possible to prevent the orbiting scroll
3
from rotating.
Accordingly, under the condition restricted to perform the rotating motion by the rotation preventive member
10
, the orbiting scroll
3
can compress a fluid while performing the orbiting motion in a specific orbit around the upper surface of the frame
1
.
However, in the conventional scroll compressor, because the rotation preventive member
10
has a ring shape, as depicted in
FIG. 4
, when the orbiting scroll
3
orbits, a bending stress occurs on the ring body
11
by a reaction force F
0
, F
f
acting on each contacting face (
0
01
) (
0
02
) (
0
f1
) (
0
f2
) of each key (
12
a
,
12
b
), (
12
c
,
12
d
).
Because the bending stress occurred at the ring body
11
is relatively larger than a general tension stress or a compressive stress, the rotation preventive member
10
may be deformed. Accordingly, in order to prevent the deformation of the rotation preventive member
10
, the rotation preventive member
10
has to be designed in large, accordingly the cost of materials has to be increased.
In addition, when the rotation preventive member
10
is designed in large, a weight of the rotation preventive member
10
is increased, a reaction force variation range of each key
12
a
,
12
b
,
12
c
,
12
d
greatly influenced by an inertia is increased, accordingly a maximum reaction force acting on each key
12
a
,
12
b
,
12
c
,
12
d
of the rotation preventive member
10
is increased.
In more detail,
FIG. 5
is a graph illustrating a reaction force value occurred at each contacting face (
0
01
) (
0
02
) (
0
f1
) (
0
f2
) of the rotation preventive member
10
according to an orbit angle when a mass of the rotation preventive member
10
is one third of a mass of the orbiting scroll
3
.
FIG. 6
is a graph illustrating a reaction force value occurred at each contacting face (
0
01
) (
0
02
) (
0
f1
) (
0
f2
) of the rotation preventive member
10
according to an orbit angle when a mass of the rotation preventive member
10
is 0. With reference to
FIGS. 5 and 6
, a reaction force between the contacting faces (
0
01
) (
0
02
) of the rotation preventive member
10
contacting to the orbiting scroll
3
is increased as a mass of the rotation preventive member
10
is increased.
Accordingly, abrasion of each key
12
a
,
12
b
,
12
c
,
12
d
is increased in accordance with an increase of a mass of the rotation preventive member
10
, according to it a leakage of compressing gas may be occurred and a noise due to collision between each key
12
a
,
12
b
,
12
c
,
12
d
with each key groove
3
b
,
3
c
,
1
a
,
1
b
may be increased.
SUMMARY OF THE INVENTION
Accordingly, in order to solve above-mentioned problems, it is an object of the present invention to provide a rotation preventive device for a scroll compressor which is capable of retrenching a production cost by reducing a size of a rotation preventive member so as to act a tension stress and a compressive stress on the rotation preventive member besides a bending stress.
It is anoth
Birch & Stewart Kolasch & Birch, LLP
Denion Thomas
LG Electronics Inc.
Trieu Theresa
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