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BACKGROUND OF THE INVENTION
This invention relates to scroll fluid apparatus, and more particularly it
is concerned with a construction of the scroll fluid apparatus suitable
for discharging a lubricant collecting at an outer peripheral portion of
an end plate of an orbiting scroll member to reduce a drive force required
to operate the apparatus.
In, for example, Japanese Laid Open Pat. No. 73886/82 a sealed type
electric compressor in the form of a scroll fluid apparatus is proposed
which comprises a compressor section and an electric motor section
contained in a sealed container, and a fluid passage extending through a
wall of the sealed container and connected through a line to outside
equipment which may be an evaporator or condenser of a refrigerating
apparatus. The scroll type compressor section comprises a fixed scroll
member and an orbiting scroll member in meshing engagement with each other
which constitute the essential portions of the compressor. The fixed
scroll member and orbiting scroll member each includes an end plate, and a
wrap of vortical form located in upright position on the each end plate
and having an involute curve or a curve similar to that. A suction port
for a fluid is formed in a position in the vicinity of an outer side of a
space defined between the two scroll members, and a discharge port opens
in a position close to the center of the fixed scroll member. A rotation
preventing member in the form of an Oldham's ring is mounted between the
orbiting scroll member and a frame or the fixed scroll member to prevent
the orbiting scroll member from rotating on its own axis, and a crankshaft
is kept in engagement with the orbiting scroll member through a bearing to
move the orbiting scroll member in orbiting movement about the center of
the fixed scroll member without rotating on its own axis, so as to
compress a fluid in the sealed space defined between the two scroll
members and discharge the compressed fluid through the discharge port. To
compress the fluid and discharge the compressed fluid efficiently as
described hereinabove, it is necessary that the orbiting scroll member be
forced against the fixed scroll member with a suitable force. The axial
biasing force which urges the orbiting scroll member against the fixed
scroll member is obtained by the difference between the pressure in
compression chambers and the pressure applied to the back of the orbiting
scroll member, and the difference in pressure is introduced through a fine
communicating port communicating the compression chambers with the back of
the orbiting scroll member.
Meanwhile, a lubricant collecting in the sealed container is utilized for
cooling the bearings and sliding portions of the compressor section. The
lubricant is fed to each bearing through oil ducts formed in the
crankshaft by the difference in pressure between an intermediate pressure
and a high pressure, and then flows into a back pressure chamber on the
back of the orbiting scroll member. The lubricant flowing into the back
pressure chamber is discharged therefrom in suitable amount into the
compression chambers through the communicating port during operation and
entrained in the compressed gas to flow in circulation therewith.
In the scroll fluid apparatus of the aforesaid construction, the lubricant
flowing into the back pressure chamber is discharged into the compression
chambers through the communicating port formed in the end plate of the
orbiting scroll member. However, if the amount of the lubricant fed to the
bearings exceeds the discharge capacity of the communicating port, then
the back pressure chamber would be filled with the lubricant which would
be agitated by a balance weight, causing a loss of power. The lubricant
would invade a clearance in an outer peripheral portion of the end plate
of the orbiting scroll member, and if such clearance were filled with the
lubricant, the lubricant would be compressed by the orbiting movement of
the orbiting scroll member, thereby causing an increase in the power
necessary for operating the apparatus.
SUMMARY OF THE INVENTION
This invention has as its object the provision of a scroll fluid apparatus
capable of avoiding compression of oil in the outer peripheral portion of
the end plate of the orbiting scroll member, to thereby prevent an
increase in the power necessary for operating the apparatus.
According to the invention, a scroll fluid apparatus is provided which
comprises a fixed scroll member including a disc-shaped end plate and a
wrap of a vortical form located in upstanding position on the end plate,
and an orbiting scroll member including a disc-shaped end plate and a wrap
of a vortical form located in upstanding position on the end plate. The
two scroll members are maintained in meshing engagement with each other
with the respective wraps facing inwardly to allow the orbiting scroll
member to move in orbiting movement with respect to the fixed scroll
member without rotating on its own axis. The fixed scroll member is formed
with a discharge port opening at its central portion and a suction port
opening at its outer peripheral surface to draw a gas by suction through
the suction port and allow the same to flow in a sealed space defined
between the two scroll members and reduce its volume during operation to
thereby compress the gas into a compressed gas which is discharged through
the discharge port. A clearance is defined between an outer peripheral
surface of the end plate of the orbiting scroll member and a wall facing
the outer peripheral surface, with the clearance successively changing its
volume as the orbiting scroll member moves in orbiting movement. At least
one pressure relieving space communicates with the clearance for
conveniently effecting fluid discharge from the clearance to avoid
compression of the fluid.
The term "fluid discharge" as used in this specification refers not only to
the discharge of the fluid into other space, that is, to a space on the
lower pressure side or a compression chamber, but also to the flow of the
fluid from a small size portion of the clearance to a large size portion
thereof. Stated differently, the term "fluid discharge" includes the
discharge of a fluid from a clearance space of small size to a clearance
space of large size.
What is important in the invention is to discharge a fluid or cause the
same to flow as quickly as possible from a smallest size portion of a
clearance which successively changes its volume as the orbiting scroll
member moves in orbiting movement into other space of large size. To this
end, it is most preferable to bring the smallest size portion of the
clearance into direct communication with the space of large size.
However, to facilitate the flow of the fluid from the smallest size portion
of the clearance, the fluid may be first led to a space corresponding to
such space of large size or a large size portion of the clearance created
by the orbiting movement of the orbiting scroll member, and then the fluid
may be introduced into a compression chamber or a space on the lower
pressure side.
Depending upon the condition of operaton, the fluid discharge may be
carried out continuously or be effected intermittently, with the
intermittent fluid discharge being carried out by opening and closing a
duct formed in the fixed scroll member or the end plate of the orbiting
scroll member while the orbiting scroll member moves in orbiting movement.
In any case, the provision of the pressure relieving space for quickly
reducing the volume of the fluid in a small size portion of the clearance
prevents the fluid from being compressed and allows the power necessary
for driving the apparatus to be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a scroll fluid apparatus serving as a sealed
type electric compressor;
FIG. 1a is a view of a clearance formed by the orbiting movement of the
orbiting scroll member, showing a rise in the pressure of a fluid in the
clearance as the fluid is compressed by the orbiting movement;
FIG. 2 is a fragmentary plan view of the frame formed with a peripheral
groove along the entire outer periphery thereof;
FIG. 3 is a cross-sectional view taken along the line III--III in FIG. 2;
FIG. 4 is a fragmentary plan view of the frame formed with a plurality of
peripheral grooves located discretely along its outer periphry;
FIG. 5 is a cross-sectional view taken along the line V--V in FIG. 4;
FIG. 6 is a fragmentary plan view of the frame formed with a plurality of
recesses discretely located along its outer periphery;
FIG. 7 is a cross-sectional view taken along the line VII--VII in FIG. 6;
FIG. 8 is a sectional view of the end plate of the orbiting scroll member
having a cutout;
FIG. 9 is a fragmentary plan view of the frame formed with a plurality of
grooves at its outer periphery;
FIG. 10 is a cross-sectional view taken along the line X--X in FIG. 9;
FIG. 11 is a fragmentary plan view of the frame formed with a plurality of
recesses disposed discretely along its outer periphery, a groove extending
along the entire outer periphery and a plurality of radial grooves;
FIG. 12 is a cross-sectional view taken along the line XII--XII in FIG. 11;
FIG. 13 is a fragmentary plan view of the back of the end plate of the
orbiting scroll member formed with a plurality of grooves;
FIG. 14 is a cross-sectional view taken along the line XIV--XIV in FIG. 13;
FIG. 15 is a fragmentary sectional view of the fixed scroll member formed
with a duct for communicating the clearance with the low pressure space;
FIG. 16 is a fragmentary sectional view of the end plate of the orbiting
scroll member formed with a duct for communicating the clearance with the
low pressure space;
FIG. 17 is a fragmentary sectional view of the fixed scroll member formed
with a duct for communicating the clearance with the compression chamber;
FIG. 18 is a fragmentary sectional view of the orbiting scroll member
formed at its end plate with a duct for communicating the clearance with
the compression chamber;
FIG. 19 is a fragmentary sectional view of the orbiting scroll member
formed at its end plate with an inclined duct for communicating a gap
between the back of the end plate and the bottom surface of the frame;
FIG. 20 is a fragmentary plan view of the frame formed with the grooves
shown in FIGS. 2 and 9;
FIG. 21 is a fragmentary cross sectional view taken along the line XXI--XXI
in FIG. 20, showing the end plate of the orbiting scroll member formed
with the duct shown in FIG. 18;
FIG. 22 is a fragmentary sectional view of the fixed scroll member, showing
a duct communicated with the clearance which may be opened and closed
intermittently;
FIG. 23 is a view similar to FIG. 22 but showing the duct in the closed
position;
FIG. 24 is a fragmentary sectional view of the fixed scroll member, showing
another constructional form of the duct shown in FIG. 22;
FIG. 25 is a fragmentary sectional view of the fixed scroll member, showing
another constructional form of the duct shown in FIG. 22, i.e. in a
slanting position;
FIG. 26 is a fragmentary sectional view of the fixed scroll member, showing
a modification of the duct shown in FIG. 24;
FIG. 27 is a fragmentary sectional view of the orbiting scroll member
formed at its end plate with a duct intermittently communicated with the
clearance;
FIG. 28 is a view similar to FIG. 27 but showing the duct intermittently
communicated with the clearance in a slanting position;
FIG. 29 is a fragmentary sectional view of the fixed scroll member formed
with a duct communicating the clearance with the compression chamber;
FIG. 30 is a fragmentary sectional view of the frame formed with a duct
communicating the compression chamber with a groove formed on the bottom
surface of the frame;
FIG. 31 is a fragmentary sectional view of the frame formed with a duct
intermittently communicated with the compression chamber;
FIG. 32 is a view similar to FIG. 31 but showing another constructional
form of the duct; and
FIG. 33 is a fragmentary sectional view of the frame and the orbiting
scroll member, showing the end plate of the orbiting scroll member formed
at its back with a groove communicating with the groove formed on the
bottom surface of the frame.
DETAILED DESCRIPTION
Referring now to the drawings wherein like reference numerals are used
throughout the various views to designate like parts and, more
particularly, to FIG. 1, according to this figure, a scroll fluid
apparatus includes an orbiting scroll member 1 including a disc-shaped end
plate 1a and a wrap 1b of a vortical form located in upstanding position
on the end plate 1a, a fixed scroll member 2 including a disc-shaped end
plate 2a and a wrap 2b of a vortical form located in upstanding position
on the end plate 2a, and a frame 3 constituting a compressor section of a
unitary structure wherein the orbiting and fixed scroll members 1 and 2
mesh with each other. The compressor section is fitted in and secured to a
cylinder 4 constituting a sealed container. An Oldham's key 5 and an
Oldham's ring 6 in sliding engagement with each other are mounted in a
back pressure chamber 17 formed at the back of the end plate 1a of the
orbiting scroll member 1 between the orbiting scroll member 1 and the
frame 3. A crankshaft 7 includes an eccentric shaft portion 7a which is in
engagement with the orbiting scroll member 1 through a swing bearing 8. A
sealed space 9 is defined between the end plates 1a and 2a of the orbiting
and fixed scroll members 1 and 2 as the wraps 1b and 2b thereof mesh with
each other. The sealed space 9 includes a plurality of compression
chambers 230 (see FIG. 17) which have their volumes successively reduced
while being alternately communicated with a discharge port 10 formed in a
central portion of the end plate 2a of the fixed scroll member 2. The
discharge port 10 opens in a space 11 defined by a chamber plate 26
constituting a part of the sealed container. A balance weight 12 is fixed
to the crankshaft 7 which is journalled by an upper main bearing 13 and a
lower main bearing 14. The crankshaft 7 supports, at an end portion
thereof a rotor 15 of a motor whose stator 16 is secured to the frame 3 by
bolts 27. A communicating port 18 is formed in the end plate 1a of the
orbiting scroll member 1 to maintain communication between the sealed
space 9 and the back pressure chamber 17. An oil duct 19, extending
through the crankshaft 7, has one opening in an oil feeding section 28 at
a lower end portion of the crankshaft 7 and the other opening in an end
face of the eccentric shaft portion 7a. The oil duct 19 is maintained in
communication with the upper main bearing 13 through an oil passage 19a.
Another oil duct 20 has one end opening in the oil feeding section 28 at
the lower end portion of the crankshaft 7 and the other end opening in the
lower main bearing 14 through another oil passage 20a. A suction pipe 23,
extending through a wall of the cylinder 4 has one end connected to
equipment on a lower pressure side, such as for example, an evaporator,
and the other inserted in a hole 30 formed in a wall of the fixed scroll
member 2. The suction pipe 23 is joined by welding as indicated at 4a to
the cylinder 4. A tubular passage 29 is inserted in the hole 30 and fixed
thereto to communicate with a suction port 21 communicated with the lower
pressure side of the sealed space 9. The cylinder 4 forming the sealed
container has a lubricant 35 collected at a bottom portion thereof, with a
discharge pipe 36 extending through the wall of the cylinder 4, and a
terminal 37 for connection to a power source is mounted on a cap of the
chamber plate 26. An evaporator 40, an expansion valve 41 and a condenser
42 are connected with the compressor section of the aforesaid construction
to form the refrigeration cycle.
In operation, when the scroll compressor is driven for operation, the
orbiting scroll member 1 is driven by a motor through the crankshaft 7 to
move in orbiting movement, to draw a gas from the evaporator 40 on the
lower pressure side through the suction pipe 23 into the sealed space 9 by
suction. The gas is compressed into a compressed gas of high temperature
and pressure which is discharged through the discharge port 10 into the
space 11 in the chamber plate 26. The compressed gas which contains oil
flows through a passage 32 to a chamber where the motor is contained.
The motor is higher in temperature than the compressed gas because it
generates heat as a result of its rotation, so that the motor is cooled
when brought into contact with the gas. The oil entrained in the gas is
separated from the gas when the gas is brought into contact with the motor
and other parts and collects in an oil sump at the bottom of the sealed
container while the gas having the majority of the entrained gas separated
therefrom flows through the discharge pipe 36 into the condenser 42 where
it is subjected to heat exchange with, for example, outdoor air and
changes to a liquid state by giving off heat. The fluid in the liquid
state is expanded by having its pressure reduced by the expansion valve 41
into a gas of low temperature and pressure which flows into the evaporator
40 where it cools, for example, air by its cooling action. After
performing the cooling action, the gas is drawn by suction again through
the suction pipe 23 into the scroll compressor, to be compressed again.
Meanwhile, the lubricant 35 is drawn from the oil feeding section 28 by the
difference in pressure between the high pressure inside the sealed
container produced by the operation of the compressor and the intermediate
pressure prevailing in the back pressure chamber 17 and fed through the
oil ducts 19 and 20 and the oil passages 19a and 20a into the upper and
lower main bearings 13 and 14 and the swing bearing 8 to lubricate same.
After lubricating the bearings, the oil collects in the back pressure
chamber 17 and is led therefrom through the communicating port 18
communicating the back pressure chamber 17 with the sealed space 9 to the
sealed space 9 where it is compressed together with the gas.
During the aforesaid operation, the lubricant collecting in the back
pressure chamber 17 seeps through a small gap between an under-surface 51
of the end plate 1a of the orbiting scroll member 1 and a bottom surface
34 of the frame 3 into a clearance 50 between an outer peripheral surface
52 of the end plate 1a of the orbiting scroll member 1 and an wall 33 of
the frame 3 facing each other (see FIG. 1a). The intermediate pressure of
the gas and oil in the back pressure chamber 17 is applied to the
undersurface 51 of the end plate 1a to force the same against the end
plate 2a of the fixed scroll member 2. Thus, the undersurface 51 tends to
move away from the bottom surface 34, but the gap therebetween is
restricted to a very small value even if they separate themselves from
each other.
As shown in FIG. 1a, the clearance 50 successively changes its shape
between the wall 33 of the frame 3 and the outer peripheral surface 52 of
the end plate 1a of the orbiting movement. The end plate 1a of the
orbiting scroll member 1 has a center 53 which revolves in orbiting
movement in the direction of an arrow in the figure about a center 54 of
the frame 3. When the end plate 1a of the orbiting scroll member 1 moves
to a rightmost position in FIG. 1a, the clearance 50 has a minimum size in
the vicinity of a point 55 and a maximum size in the vicinity of a point
56 disposed in a position diametrically opposed to that of the point 55.
As the orbiting scroll member 1 moves in orbiting movement, the clearance
50 gradually becomes smaller in size at a point 57 disposed posterior to
the point 55 with respect to the direction of orbiting movement of the
scroll member 1 and larger in size at a point 58 disposed anterior to the
point 55 with respect to the direction of orbiting movement of the scroll
member 1. Thus, if the oil flows into the clearance 50, then it is
compressed in the vicinity of the point 57 in which the clearance 50
becomes smaller in size with the orbiting movement of the orbiting scroll
member 1 and rises in pressure to a higher level than in the vicinity of
other points. This phenomenon is marked in a portion of the clearance 50
posterior to the point 55 of minimum size and the pressure in such portion
rises to a maximum level as indicated at 60, so that a force is produced
which acts in a direction opposite to the direction of the orbiting
movement of the orbiting scroll member 1. Enabling the orbiting scroll
member 1 to move in orbiting movement by overcoming this reverse-acting
force would require an additional drive force to be exerted in the
orbiting scroll member 1.
Thus, by releasing the oil from the minimum size portion of the clearance
50 as quickly as possible, it is possible to avoid the oil being
compressed and thus to eliminate the need to use an additional drive
force. FIGS. 2 and 3 show means provided by the invention for discharging
as quickly as possible the oil from the vicinity of the minimum size point
55 of the clearance 50 to a space of larger volume. The frame 3 is formed
with an annular groove 70 at the bottom surface 34 thereof, so that the
oil in the vicinity of the minimum size point 55 flows through the groove
70 to the vicinity of the maximum size point 56, thereby avoiding the oil
being compressed in the vicinity of the minimum size point 55. The groove
70 and other clear space of larger volume function as a pressure relieving
space for avoiding compression of the fluid.
In FIG. 3, a considerably large gap is shown as being defined between the
undersurface 51 of the end plate 1a of the orbiting scroll member 1 and
the bottom surface 34 of the frame 3. However, in actual practice, such
gap is very small. The gap shown in FIG. 3 is exaggerated to enable the
action of the intermediate pressure in the back pressure chamber 17 to
force the end plate 1a of the orbiting scroll member 1 against the end
plate 2a of the fixed scroll member to be better understood. Bolt holes 61
enables inserting bolts for securing of the fixed scroll member 2 to the
frame 3.
As shown in FIGS. 4 and 5 means for discharging the oil from the vicinity
of the minimum size point 55 may comprise a plurality of peripheral
grooves 71 located discretely at the bottom surface 34 of the frame 3 in
place of the annular groove 70 shown in FIGS. 2 and 3. The discrete
peripheral grooves 71 perform the same function as the annular groove 70.
As shown in FIGS. 6 and 7, to dischange the oil from the vicinity of the
minimum size point 55, it is also possible to provide a plurality of
recesses 80 located discretely along the wall 33 of the frame 33 and
constituting pressure relieving spaces maintained in communication with
the vicinity of the minimum size point 55. The provision of the discrete
recesses 80 can achieve the effect of relieving the pressure.
In FIG. 8, a cutout 90 is formed at a corner of the end plate 1a of the
orbiting scroll member 1 between its undersurface 51 and its outer
peripheral surface 52 and extending along the entire circumference of the
end plate 1a.
In order to enable a discharging of the compressed fluid into the back
pressure chamber 17, as shown in FIGS. 9 and 10, a plurality of radial
grooves 100 may be formed at the bottom surface 34 of the frame 3 and
maintained in communication with the back pressure chamber 17 serving as a
pressure relieving space. As the end plate 1a moves close to the vicinity
of the minimum size point 55 near the wall 33 of the frame 3, the oil
flows through the grooves 100 to the back pressure chamber 17.
FIGS. 11 and 12 provide an illustration of a combination of the annular
groove 70 shown in FIGS. 2 and 3 and the recesses 80 shown in FIGS. 6 and
7, with FIGS. 13 and 14 showing a plurality of grooves 110 located at the
undersurface 51 of the end plate 1a of the orbiting scroll member 1 for
discharging the oil into the back pressure chamber 17. As shown in FIG.
15, a communicating duct 200 is formed in the fixed scroll member 2 and
with one end of the communicating duct 200 opening in the vicinity of the
minimum size point 55 or maximum size point 56 of the clearance 50 and the
other end opening in the sealed space 9 which is a lower pressure space. A
plug 201 seals the communicating duct 200, and a labyrinth 202 is provided
for forming a seal between the undersurface 51 of the end plate 1a of the
orbiting scroll 1 and the bottom surface 34 of the frame 3 to avoid the
oil being discharged in excess into a lower pressure section. The
communicating duct 200 opens at 203 in the clearance 50 and successively
brings all the points from the minimum size point 55 to the maximum size
point 56 in the clearance 50 which changes its shape as the orbiting
scroll member 1 moves in orbiting movement into communication with the
sealed space 9.
FIG. 16 shows a communicating duct 204 formed in the end plate 1a of the
orbiting scroll member 1. In this constructional form, it is unnecessary
to close those ducts with plugs after being formed.
In FIG. 17, a communicating duct 205 is shown as extending through the end
plate 2a of the fixed scroll member 2 and communicating with a compression
chamber 230. This constructional form offers the advantage that a
reduction in volume efficiency can be avoided because the fluid is
discharged into the fluid being compressed. FIG. 18 shows a communicating
duct 206 formed in the end plate 1a of the orbiting scroll member 1 and
communicating with the compression chamber 230. This constructional form
eliminates the need to insert plugs in ducts.
In the constructional forms shown in FIGS. 17 and 18 in which the fluid is
discharged into the compression chamber 230, the need to provide a
labyrinth for avoiding the discharge of oil in excess can be eliminated,
thereby simplifying the construction.
In FIG. 19, an inclined communicating duct 207 extends through the end
plate 1a of the orbiting scroll member 1 and opens at one end at an
interface between the undersurface 51 of the end plate 1a and the bottom
surface 34 of the frame 3 and at an opposite end in the sealed space 9
which is a lower pressure space. In this constructional form, the open one
end of the communicating duct 207 is closed as the end plate 1a of the
orbiting scroll member 1 is brought out of contact with the end plate 2a
of the fixed scroll member 2 and the undersurface 51 thereof is brought
into contact with the bottom surface 34 of the frame 3, so that the
discharge of oil stops and the volume of discharged oil can be controlled.
FIGS. 20 and 21 show a constructional form which has the highest practical
value and which constitutes a combination of the constructional forms
shown in FIGS. 2, 9 and 18. It has been ascertained that the
constructional form shown in FIGS. 20 and 21 enables the scroll type
compressor to operate with a minimum input of power for driving same.
In the constructional forms described hereinabove, the oil in the clearance
50 is discharged therefrom or made to flow therein in a constant volume at
all times during operation.
Constructional forms presently to be described are those in which the
discharge of the oil takes place intermittently or is drastically
restricted. By drastically restricting the discharge of the oil, it is
possible to avoid the excessive discharge of the oil from the clearance
50.
In FIGS. 22 and 23, a communicating duct 301 is formed in the fixed scroll
member 1 which has an end 300 opened and closed by the end plate 1a of the
orbiting scroll member 1 as it moves in orbiting movement and communicates
at its opposite end with the sealed space 9 which is a lower pressure
space. In FIG. 22, the end 300 is shown as communicating with the
clearance 50 in the vicinity of the maximum size point 56; and in FIG. 23,
the end 300 is shown as being closed by the end plate 1a because it is
disposed in the vicinity of the minimum size point 55 of the clearance 50.
By bringing the end 300 of the communicating duct 301 cyclically to the
two positions shown in FIGS. 22 and 23, it is possible to intermittently
discharge the oil from the clearance 50 into a space on the lower pressure
side. A plug 302 is provided for closing an end of the communicating duct
301. In FIG. 24, the communicating duct 301 opens in a recess 303 formed
at the fixed scroll member 2 which has an opening of substantialy the same
area as the vicinity of the maximum size point 56 of the clearance 50.
Thus, as the end plate 1a of the orbiting scroll member 1 moves
rightwardly in the figure, the opening of the recess 303 is reduced in
area and, consequently, the passage through the duct 301 is reduced in
area, to thereby restrict the volume of the oil discharged from the
clearance 50. As means for intermittently discharging the oil from the
clearance 50, an inclined communicating duct 304 may be provided as shown
in FIG. 25 which can achieve the end with less time and labor for
fabrication than the constructional forms shown in FIGS. 22 and 23. In
FIG. 26, a combination of the inclined communicating duct 304 shown in
FIG. 25 with the recess 303 shown in FIG. 24 is shown. In FIG. 27, a
communicating duct 305 is shown as being formed in the end plate 1a of the
orbiting scroll member 1 and having an opening 306 which is brought into
and out of communication with the sealed space 9 which is a lower pressure
section by the undersurface of the fixed scroll member 2. By this
constructional form, it is possible to control the volume of the oil
discharged from the clearance 50 by allowing the oil to be intermittently
discharged. The duct 305 shown in FIG. 27 may be inclined as shown in FIG.
28 which facilitate fabrication because duct formation can be performed in
one step.
In constructional forms shown in FIGS. 29, 30, 31 and 32, the oil is
discharged from the clearance 50 into the compression chamber 230. In FIG.
29, a communicating duct 307 is formed in the end plate 1a of the orbiting
scroll member 1 and the recess 303 alternately communicating with the
minimum and maximum size points 55 and 56 is formed at the fixed scroll
member 2, so that the area of the opening of the recess 303 can be varied
by the orbiting movement of the orbiting scroll member 1 to effect control
of the volume of the oil discharged from the clearance 50. In FIG. 30, a
communicating duct 308 having an opening 309, is formed in the end plate
1a of the orbiting scroll member 1 and communicates alternately with the
minimum and maximum size points 55 and 56 of the clearance 50 through a
groove 310 formed at the bottom surface of the frame 3. By this
arrangement, the opening 309 is opened and closed as the orbiting scroll
member 1 moves in orbiting movement. In FIG. 31, a communicating duct 311
is formed in the fixed scroll member 1. A plug 812 is provided for sealing
an end of the duct 311. In FIG. 32, a communicating duct 314 is formed in
the fixed scroll member 2 and maintained alternately in communication with
the minimum and maximum size points 55 and 56 through a recess 313 formed
at the fixed scroll member 2. In this constructional form, it is possible
to increase and decrease the area of the oil passage to control the volume
of the oil discharged from the clearance 50 without completely blocking
the passage of oil through the opening of the recess 313. FIG. 33 shows a
constructional form in which a groove 110 is formed at the undersurface 51
of the end plate 1a of the orbiting scroll member 1 and maintained in
communication with the groove 310 formed at the bottom surface of the
frame 3. In this constructional form, the area of an opening maintaining
the grooves 110 and 310 in communication with each other undergoes a
change as the orbiting scroll member 1 moves in orbiting movement, to
thereby enable control of the volume of the oil discharged into the back
pressure chamber 17 to be effected.
From the foregoing description, it will be appreciated that the invention
enables a fluid to flow in and be discharged from the clearance to a space
of large volume by virtue of the aforesaid means for discharging oil from
the clearance 50 defined betwen the wall 33 of the frame 3 and the outer
peripheral surface 52 of the end plate 1a of the orbiting scroll member 1.
This is conducive to a prevention of an increase in the power necessary
for operating the scroll type compressor which would otherwise be caused
by the compression of the oil.
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