Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2000-04-12
2001-02-13
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055200, C418S060000, C418S101000, C165S086000, C165S104260, C165S104280
Reexamination Certificate
active
06186755
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to scroll fluid machine, in which sucked fluid is compressed with stationary and revolving scrolls and discharged to the outside.
2. Description of the Related Art
A scroll fluid machine compresses fluid sucked from its peripheral part in a sealed space formed by its stationary and revolving scrolls progressively as the fluid is fed toward its central part, and discharges the compressed fluid from the central part. As the fluid is compressed, the temperature in the sealed space formed by the wraps is elevated. This poses a problem that bearings, seal members, etc. provided in drive parts are soon deteriorated. Heretofore, the scrolls are cooled to hold the temperature within a predetermined temperature.
Well-known cooling systems cool either a non-driven part, i.e., the stationary scroll, or a driven part, i.e., the revolving scroll.
FIG. 16
shows a technique concerning a non-driven part cooling system. As shown, a revolving scroll
116
which is mounted on a frame
109
provided in a sealed housing
105
, comprises a disc-like body
114
having a shaft
113
depending therefrom. The frame
109
has a central hole, in which a drive shaft
104
coupled to a drive (not shown) is fitted for rotation, and the shaft
113
is eccentrically coupled to the drive shaft
104
. The revolving scroll
116
has a wrap
115
engaging with a wrap
111
of a stationary scroll
112
.
The stationary scroll
112
has a peripheral wall having a suction hole
118
. When the revolving scroll
116
is revolved relative to the stationary scroll
112
with the rotation of the drive shaft
104
, a sealed space formed by the wraps
111
and
115
is progressively reduced in volume, thus compressing gas entering the sealed space. The compressed gas is discharged from a discharge hole
121
formed in a central part of the stationary scroll
112
through a discharge pipe
120
to the outside.
A plurality of radially spaced-apart heat pipes
122
are provided in the body
110
of the stationary scroll
112
to remove heat generated in a compression stroke as described above.
FIG. 17
shows a well-known cooling system for cooling driven part, i.e., the revolving scroll.
A housing
211
as shown comprises a rear and a front housing part
212
and
213
, and a drive shaft
214
is supported for rotation by bearings
215
in a bearing portion of the rear housing part
212
. The drive shaft
214
has an extension projecting outward from the bearing portion and coupled to a motor (not shown). The drive shaft
214
also has an eccentric portion
214
b,
which has an eccentric axis
02
—
02
with respect to the axis
01
—
01
of the drive shaft
214
by a distance &dgr;.
A revolving scroll
216
which is coupled to the eccentric portion
214
b
of the drive shaft
214
, has a disc-like plate
216
a
having a mirror finished front surface, a spiral wrap
216
b
formed on the front side of the mirror finished plate
216
a,
a boss
216
c
formed as the driving center with an axial line
02
—
02
on the rear side of the plate
216
a
and having smaller diameter than the inner peripheral surface edge of above portion
213
b,
a ring-like ridge
216
d
formed on the rear side of the above
216
a
and on the periphery thereof, and a plurality of radial vent holes
216
e
formed in a diameter direction above the ridge
216
d.
A stationary scroll
221
, which is secured to the front housing part
213
, has a disc-like plate
211
a
having a mirror finished rear surface, a spiral wrap
221
b
formed on the rear side of the plate
211
a
and a peripheral wall
221
c
surrounding the wrap
221
b.
The wraps
216
b
and
221
b
of the revolving and stationary scrolls
216
and
221
engage with or wrap each other at a predetermined deviation angle, and they form a plurality of compression chambers or spaces when the revolving scroll
216
is revolved.
The drive shaft
214
has a counterweight
225
mounted on its portion extending in the rear housing part
212
, and a centrifugal fan
226
is mounted on the counterweight
225
to generate cooling air flow with the rotation of the drive shaft
214
.
In the prior art non-driven part cooling system shown in
FIG. 16
, in which the heat pipes
122
are provided in the stationary scroll body, the heat absorbing portions of the heat pipes
122
are more remote from the revolving scroll which is driven than from the stationary scroll. Therefore, the neighborhood of the bearings, seal members and other parts which are driven in contact with the revolving scroll
116
in the driving thereof, is cooled less efficiently compared to the cooling of the stationary scroll. This means that uniform temperature distribution cannot be obtained.
The heat radiating portions of the heat pipes
122
are cooled by their heat radiation to the sealed housing inner space
105
a,
which is filled with gas-sucked through a suction pipe
119
.
In communication with the space
105
a
is the suction hole
118
, through which gas enters the compression space which is formed by the stationary and revolving scrolls. This means that gas having been elevated in temperature by the heat radiation from the heat pipes
122
again enters the compression space through the suction hole
118
, thus reducing the cooling efficiency.
In order to prevent the cooling efficiency reduction, it is necessary to provide special cooling means on an external part to which the suction pipe
119
is connected, thus complicating the construction and increasing the size of the apparatus.
In the well-known driven part cooling system shown in
FIG. 17
, with the rotation of the drive shaft
214
external gas is sucked through a suction passage
227
by the centrifugal fan
226
and led through a ring-like space B and a cooling air passage
220
to be discharged through a discharge passage
228
.
Since in this system the gas having cooled down a central part of the revolving scroll
216
is discharged along the rear side of the revolving scroll
216
and through the discharge passage
228
, the provision of the discharge passage is necessary. In addition, in order to increase the cooling efficiency, a cooling fan for cooling the rear side of the stationary scroll
221
has to be provided, thus increasing the size of the apparatus.
OBJECT AND SUMMARY OF THE INVENTION
The invention was made in view of the affairs discussed above, and it has an object of providing a scroll fluid machine with an improved cooling efficiency.
Another object of the invention is to provide a scroll fluid machine with improved durability.
A further object of the invention is to provide a scroll fluid machine which is reduced in size.
According to the invention, in a scroll fluid machine comprising stationary scrolls each having a wrap embedded spirally in a scroll body such as to extend from a central part toward the outer periphery of the scroll body, and a revolving scroll having spiral wraps embedded in a scroll body and engaging with the spiral wraps of the stationary scrolls, the revolving scroll being coupled to a drive shaft coupled to a drive, it is featured that cooling means is provided in the drive shaft.
With this construction according to the invention, the drive shaft can be cooled directly. Since the revolving scroll is driven by the drive shaft coupled to the drive, it is possible to cool heat generated in a process, in which fluid sucked from the edge of the scroll is led to a central part thereof while being progressively compressed. It is thus possible to obtain efficient cooling of bearings and seal members provided around the revolving scroll and also those provided around the drive shaft.
It is also possible to eliminate the thermal expansion difference between the stationary scrolls and the revolving scroll, provide a uniform temperature distribution, prevent scoring of the wraps, extend the grease maintenance cycle and improve the durability.
It is further possible to reduce heat generation for reducing the scroll clearance, increasing the operation speed and incr
Anest Iwata Corporation
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Vrablik John J.
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