Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2001-04-09
2002-10-08
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S057000
Reexamination Certificate
active
06461131
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a radial compliance scroll compressor, and more particularly, to a radial compliance scroll compressor for minimizing friction loss and leakage loss between wraps of an orbiting scroll and a fixed scroll.
2. Description of the Background Art
Conventionally, a compressor converts a mechanical energy into a compression energy of compressible fluid, and it is classified into a reciprocating type, scroll-type, centrifugal-type(generally, turbo-type), and vane-type(generally, rotary-type). Among them, unlike the reciprocating-type compressor using a piston, the scroll-type compressor has a structure in which gas is sucked, compressed, and discharged by using a rotating body as the centrifugal-type and vane-type.
Such a scroll-type compressor is divided into a fixed radius scroll compressor which is configured such that an orbiting scroll orbits around the same radius all the time regardless of changes in compressing conditions, and a radial compliance scroll compressor which is configured such that the orbiting scroll goes backward in a radial direction, and then returns to the original status in order to prevent wraps from being damaged when liquid refrigerant, oil, or impurities are flowed into a compression chamber to thus abnormally increase pressure in the compression chamber.
To vary the orbital radius of the orbiting scroll in this radial compliance scroll compressor, the methods of inserting a slide bush or slide block, or an eccentric bush between the crank shaft and the orbiting scroll are commonly known. Among them, the present invention relates to a radial compliance scroll compressor for intervening an eccentric bush.
As illustrated in
FIG. 1
, such a radial compliance scroll compressor is configured such that: a main frame
2
and a sub frame
3
are fixed at both upper and lower sides of the inner circumferential surface of a casing
1
filled with oil at an adequate height; a driving motor
4
having a stator
4
A and a rotor
4
B is fixedly installed between the main frame
2
and the sub frame
3
; a crank shaft
5
is forcibly inserted into the center of the rotor
4
B of the driving motor
4
through the main frame
2
; an orbiting scroll
6
having an involute wrap
6
a
and being eccentrically coupled to the crank shaft
5
is orbitably installed on the upper portion of the main frame
2
; a fixed scroll
7
having an involute wrap
7
a
engaged with the wrap
6
a
of the orbiting scroll
6
to form a plurality of compression chambers is fixedly installed at the periphery portion of the main frame
2
on the upper surface of the orbiting scroll
6
; and a discharge cover
8
dividing the interior of the casing
1
into a discharge pressure area, i.e., a high pressure portion, and a suction pressure area, i.e., a low pressure portion, is fixed to the inner circumferential surface of the casing
1
at the upper side of the fixed scroll
7
.
At the front end surface of the crank shaft
5
, a driving pin portion
5
a
for eccentrically rotating the orbiting scroll
6
is eccentrically protruded, and an oil passage
5
b
slantingly extends through the center of the driving pin portion
5
a
to the lower end of the crank shaft
5
.
As illustrated therein
FIG. 2
, an eccentric bush
9
inserted into a boss portion
6
b
of the orbiting scroll
6
for thereby retreating the orbiting scroll
6
in a radius direction upon abnormal compression is eccentrically inserted into the driving pin portion
5
a,
and a stopper pin
10
for restricting the rotational movement of the eccentric bush
9
is inserted into the eccentric bush
9
so that it has a predetermined radial movable range.
More specifically, the upper half portion of the stopper pin
10
is inserted into to the eccentric bush
9
, and the lower half portion thereof is movably inserted into a stopper groove
5
d
provided at the front end surface
5
c
of the crank shaft
5
.
In the drawings, unexplained reference numeral
2
a
designates a through hole forming a radial bearing surface of the crank shaft
5
.
The thusly configured scroll compressor in the conventional art will be operated as follows.
That is to say, the rotor
4
B orbits the orbiting scroll
6
while being rotated together with the crank shaft
5
in the interior of the stator
4
A by an applied power. At the same time, the orbiting scroll
6
undergoes an orbiting motion at a distance of the orbital radius from the pivot of the shaft by an Oldham ring(not shown) to thus form a plurality of compression chambers between the two wraps
6
a
and
7
a.
The volume of the compression chamber is reduced as the compression chambers move toward the center by a continual orbital motion of the orbiting scroll
6
, resulting in discharging of sucked gaseous refrigerant.
At this time, in the case that the gaseous refrigerant flowed into the compression chamber remains in a normal state, the wrap
6
a
of the orbiting scroll
6
and the wrap
7
a
of the fixed scroll
7
contact with each other to thus form a closed space in the compression chambers at both sides, thereby making the eccentric bush
9
and the stopper pin
10
keep their position as shown in FIG.
4
A. On the contrary, in the case that the gaseous refrigerant flowed into the compression chambers contains more than a predetermined amount of liquid refrigerant, oil, or other impurities as described above□□, the pressure of the compression chamber is abnormally increased to make the orbiting scroll
6
tend to go backward. This tendency of going backward is delivered to the eccentric bush
9
inserted into the boss portion(shown in
FIG. 2
)
6
b
of the orbiting scroll
6
. This eccentric bush
9
is rotated in the counterclockwise direction (the direction in which the orbiting scroll goes backward) until it reaches the stop position of the stopper pin as shown in
FIG. 4B
, and the wrap
6
a
of the orbiting scroll and the wrap
7
a
of the fixed scroll are isolated from each other. At this time, compression gas in a high pressure compression chamber(HR) is leaked into a low pressure compression chamber(LR), and then the wrap
6
a
of the orbiting scroll is restored to the original state, thus preventing the damage to the wraps
6
a
and
7
a
due to an However, in the conventional scroll compressor as described above, since the stopper pin
10
is provided at a predetermined interval from the driving pin portion
5
a,
the diameter(D
1
) of the crank shaft
5
must be formed larger than the gap between the stopper pin
10
and the driving pin portion
5
a
as illustrated in FIG.
3
. In addition, the diameter of the through hole
2
a
of the main frame
2
supporting thcrank shaft in a radius direction also become larger for thereby increasing the frictional area between the crank shaft
5
and the main frame
2
. Therefore, there occurs a problem that the motor efficiency is degraded due to friction loss during driving of the compressor as well as the material cost is increased.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a radial compliance scroll compressor capable of minimizing friction loss between a main frame and a bearing surface by decreasing the diameter of a crank shaft.
To achieve the above object, there is provided a radial compliance scroll compressor according to the present invention, where two scrolls having involute wraps are engaged with each other, the orbiting scroll of the two scrolls having a boss portion eccentrically coupled to a driving pin portion formed on the front end surface of a crank shaft undergoes an orbiting motion to thus form a plurality of compression chambers whose positions are continually moved between the two wraps, and the orbiting scroll coupled to the crank shaft goes backward in a radial direction within a predetermined range to thus isolate the wraps of the two scrolls from each other and then return to the normal state, thereby forming a compression chamber, which is characterized in that: an ecce
Birch & Stewart Kolasch & Birch, LLP
Denion Thomas
LG Electronics Inc.
Trieu Theresa
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