Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ROTARY COMPRESSOR LUBRICATION ARRANGEMENT
This invention pertains to hermetic rotary
compressors for compressing refrigerant in refrigera-
tion systems such as refrigerators, freezers, air
conditioners and the like. In particular, this
invention relates to the mann~r of lubricating the
sliding vanes in a rotary compressor.
In general, prior art rotary hermetic compressors
comprise a housing in which are positioned a motor
10 and a compressor cylinder. The motor drives a
crankshaft having an eccentric portion thereon for
revolving inside a bore which is located centrally in
the compressor cylinder. The eccentric has a roller
rotatably mounted thereon which revolves within the
15 bore as the crankshaft rotates. One or more sliding
vanes which are slidably received in slots located in
the cylinder wall cooperate with the roller to
provide the pumping action for compressing refrigerant
within the cylinder bore.
The operating parts of rotary hermetic compressors
are machined to extremely close tolerances and the
surfaces of the parts are finished to a high degree
in order to prevent leakage in the compressor and to
provide a very efficient compressor. It is important
25 to properly lubricate the operating parts to preserve
the surface finish. Additional]y, it is important
that proper lubrication be provided for the moving
parts of the compressor so that dynamic friction is
kept low and frictional losses are minimized.
30 Lastly, by providing adequate lubrication a minimum
amount of heat due to friction losses is generated,
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heat transfer is reduced and the compressor efficiency
is improved.
Many types of lubrication arrangements have been
provided in the prior art rotary hermetic compressors.
Generally, in the prior art arrangements some type of
pumping mechanism pumps oil upwardly from an oil sump
located in a lower portion of the compressor and
distributes the oil to the locations requiring
lubrication. The oil is generally slung outwardly to
10 the upper parts of the compressor by means of centri-
fugal force and is then allowed to drip downwardly by
gravity to lubricate the desired portions of the
compressor. Excess oil then returns to the oil sump
by means of gravity.
Some examples of prior art lubrication arrange-
ments using centrifugal and gravity distribution
forces are shown in U.S. Patent Nos. 3,804,202;
2,623,365; 2,883,101; 2,246,276; and 3,802,937.
One of the problems encountered in prior art
20 hermetic compressor lubrication arrangements has been
that insuffic:Lent oil reaches the critical areas of
the compressor. By relying on the force of gravity
or the outward centrifugal slinging of lubricant it
is possible that the moving parts in critical areas
25 of the compressor do not receive sufficient oil and
are, therefore, not properly lubricated. In particu-
lar, the sliding vane surfaces of the compressor
should be well lubricated because of the continuous
vane loads which minimizes the time for oiling in the
30 vane slot clearances of the compressor cylinder. A
more accessible oil supply facilitates lubrication
and minimizes vane wear. Furthermore, since both
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sides of the sliding vane should be well lubricated
it is desirable that the lubricating arrangement
provides sufficient lubricant to both sides of the
sliding vane.
Another problem which has been encountered in
prior art compressors is leakage of refrigerant from
the high pressure to the low pressure side of the
vane. The sliding vane of a rotary compressor
divides the low pressure area in the bore of the
10 compressor from the high pressure area in the bore
and refrigerant will therefore tend to leak around
the sides, top and bottom of the vane from -the high
pressure side to the low pressure side. Since
leakage of compressed refrigerant xepresents lost
15 work leakage decreases the efficiency of the compres-
sor. It is, therefore, desirable to provide proper
lubrication for both sides of the vane to thereby
create an oil film on both sides of the compressor
vane which forms a hydraulic seal for the sliding
20 vane in the vane slot of the cylinder wall. The oil
seal will then block refrigerant leakage around the
vane.
Yet another problem which has been encountered
in the prior art hermetic rotary compressors is that
~5 the lubricant oil is not provided under positive
pressure to the areas to be lubricated so that the
oil passages for de]ivering oi] to those areas are
not always filled with oil. Because of this deficiency
it is possible that there will be a lack of adequate
lubricant quantities for proper lubrication. It is,
therefore, desirable that oil is delivered under
positive pressure to the areas to be lubricated so
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that a sufficient supply of oil is available at all times. It is
also desirable that the lubricating oil is delivered under
positive pressure so that the oil reaches every portion of the
area to be lubricated.
The present invention overcomes the disadvantages of the
above-described prior art rotary hermetic compressors by provid-
ing an improved lubrication arranyement for a rotary compressor.
The present invention resides in a rotary compressor which
includes a vertical crankshaft rotatably journalled in a bearing
a compressor cylinder including a vane slot in a wall of the
cylinder a sliding vane slidably received in the vane slot for
compressing a compressible gas the vane having at least two
sliding surfaces and lubrication means for lubricating the vane.
The lubrication means includes an oil sump located in a lower
portion of the housing and an oil pumping means including an
axial passageway in the crankshaft the passageway communicating
with the oil sump for pumping oil upwardly from the sump. An
upwardly extending lubrication passage is provided in the
cylinder and the passage being open to the vane slot. Duct
means directly connects the lubrication passage to the axial
passageway for supplying oil upwardly under positive pressure
against gravity from the axial passageway to the lubricating
passage for lubricating the at least two sliding surfaces of the
vane.
Another aspect of the invention resides in a hermetic rotary
compressor for compressing refrigerant9 the compressor including
a housing an electric motor for driving the compressor a
crankshaft driven by the motor the crankshaft journalled in a
bearing and d cylinder adjacent to the bearing and coaxial
therewith. A vane slot is provided in the wall of the cylinder
and a vane is slidably received in the slot with oil lubrication
means being provided for lubricating the vane. The lubrication
means includes an oil sump located in the housing and an oil
pump means in the crankshaft for pumping oil upwardly from the
sump the pump means including an axial aperture in the
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crankshaft the aperture extending axially upwardly and radially
outwardly from the crankshaft axis. The upper portion of the
axial aperture communicates with a radial passage in the cranksh-
aft for conducting oil to an annular chamber surrounding the
crankshaft. A passageway in the bearing is provided for conduct-
ing the oil from the annular chamber upwardly to the vane under
positive pressure at least one elongated oil channel extending
from the cylinder. The channel is axially parallel to the
crankshaft axis and the channel is open to the slot along its
entire length and has one end open to the bearing passageway and
its other end open to the other surface of the cylinder for
supplying lubricating oil to the vane under positive pressure of
the oil pump means.
One advantage of the lubrication system of the present
invention is that adequate quantities of lubricating oil are
supplied at all times to the vane of the compressor.
Another advantage according to the present invention is that
the lubricating oil is supplied to the sliding vane of the
compressor under positive pressure so that the vane is properly
lubricated regardless of the oil level in the sump.
Yet another advantage according to the present invention is
the provision of a lubricating arrangement for the sliding vane
of a rotary hermetic compressor wherein the oil forms a hydraulic
seal around the vane of the compressor.
Still another advantage according to the present invention
is the provision of lubricating passages which are filled
adjacent the sliding vane of a compressor so that a sufficient
quantity of oil is available for lubricating the vane at the
point of heaviest load at all times.
A further advantage of the structure according to the
present invention is that frictional losses in the compressor are
kept to a minimum by means of proper lubrication and the effi-
ciency is improYed.
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A yet further advantage according to the structure of the
present invention is that a minimum amount of heat due to
frictional losses is generated heat transfer is minimized and
the compressor efficiency is improved.
It is a still further advantage of the structure of the
present invention that vane wear is minimized because of proper
lubrication of the compressor vane.
It is one object of the present invention to provide an oil
lubricating system in a rotary hermetic compressor wherein an oil
channel is provided adjacent to and communicating with the vane
and the vane slot whereby oil is pumped from the oil sump and
conducted to the oil channel under positive pressure to lubricate
the vane.
Still another object of the present invention is to provide
an oil lubricating system for a hermetic rotary compressor
wherein the vane lubricant forms a hydraulic seal for the vane
whereby leakage of refrigerant is reduced.
Figure 1 is a side sectional view of the compressor
Figure 2 is a sectional view of the compressor taken along
the line 2-2 of Figure 1
Figure 3 is a plan view of the lower bearing
Figure 4 is a side sectional view of the lower bear ng taken
along the line 4-4 of Fig~ 3;
Figure 5 is a side elevational view of the crankshaft
Figure 6 is a sectional view of the crankshaft taken along
the line 6-5 of Figure 5.
Figure 7 is a broken-away sectional view taken along the
lines 7-7 of Fig. 2.
In an exemplary embodiment of the invention as shown in the
drawings and in particular by referring to Figure 1 a compres-
SOt' is shown having a housing generally designated at 10. The
housing has a top portion 12 a lower portion 16 and a central
portion
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14. The three housing portions are hermetically
secured together as by welding or brazing. A flange
18 is welded to the bottom of housing 10 for mounting
the compressor. Located inside the hermetically
sealed housing is a motor generally designated at 20
having a stator 22 and a rotor 24. The stator is
provided with windings 23. The stator is secured to
the housing lO by an interference fit such as by
shrink fitting. The rotor 24 has a central aperture
10 25 provided therein into which is secured a crank-
shaft 26 by an interference fit. A terminal cluster
28 is provided on the top portion 12 of the compressor
for connecting the compressor to a source of electric
power.
A refrigerant discharge tube 30 extends through
top portion 12 of the housing and has an end 32
thereof extending into the interior of the compressor
as shown. The tube is sealingly connected to housing
lO at 31 as by soldering. Similarly, a suction tube
20 34 extends into the interior of compressor housing lO
and is sealed thereto as further described hereinbelow.
The outer end 36 of suction tube 34 is connected to
accumulator 38 which has support plates 40 disposed
therein for supporting a filtering mesh 42.
By referring specifically to Figures l, 5 and 6,
it can be seen that cranksha~t 26 is provided with an
eccentric portion 44 which revolves around the
crankshaft axis as crankshaft 26 is rotatably driven
by rotor 24. A counterweight 27 is provided to
30 balance eccentric 44 and is secured to the end ring
47 of rotor 24 by riveting. Crankshaft 26 is ~our-
nalled in a main bearing 46 having a cylindrical
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journal portion 48 and a generally flat planar
mounting portion 50. Planar portion 50 is secured to
housing 10 at three points 52 such as by welding of
flanges 54 to the housing as best illustrated in
Figure 2.
A second bearing or journal 56 sometimes referred
to as the outboard bearing, is also shown disposed in
the lower part of housing 10. As best illustrated in
Figures 3 and 4, lower bearing 56 is provided with a
10 journalling portion 58 having aperture 59 therein and
a generally planar portion 60. Crankshaft 26 has a
lower portion 62 journalled in journalling portion 58
of outboard bearing 56 as illustrated in Figure 1.
Located intermediate main bearing 46 and outboard
15 bearing 56 is a compressor cylinder 66. Compressor
cylinder 66, outboard bearing 56 and main bearing 46
are secured together by means of six bolts 68, one of
which is indicated in Figure 1. By referring to
Figure 2, it can be seen that six holes 70 are
20 provided in cylinder 66 for securing bearings 46,56
and cylinder 66 together. Bolts 68 extend through
holes 7~ in main bearing 46, holes 72 in cylinder 66
and into threaded holes 74 in lower bearing 56. I:E
the cylinder axial dimension is sufficiently large
25 the six bolts 68 could be replaced with twelve bolts,
six of which would secure outboard bearing 56 to
cylinder 66 and be threaded into cylinder 66. The
remaining six bolts would secure main bearing 46 to
the cylinder 66 and be threaded into cylinder 66. A
30 discharge muffler 76 is also secured to main bearing
46 by bolts 68 as indicated in Fig. 1. Compressed
refrigerant gas is discharged through relief 64 into
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discharge space 78 defined by discharge muffler 76
and the top surface of planar bearing portion 50.
From space 78 the refrigerant will exit into housing
10 through three openings 80 in muffler 76, one of
which is indicated in Figure 1.
By referring to Figures 1 and 2 it can be seen
that cylinder 66 has a vane slot 82 provided in the
cylindrical wall thereof into which is received a
sliding vane 84. Roller 86 is provided which surrounds
10 eccentric portion 44 of crankshaft 26 and revolves
around the axis of crankshaft 26 and is driven by
eccentric 44. Tip 88 of sliding vane 84 is in
continuous engagement with roller 86 as vane 84 is
urged against the roller by spring 89 received in
15 spring pocket 90. By referring to Figure 2, it can
be seen that, in operation, as the roller 86 revo~ves
around bore 92, the compression volume enclosed by
roller 86, bore 92 and sliding vane 84 will decrease
in size as roller 86 revolves clockwise around bore
20 92. Refrigerant contained in that volume will
therefore be compressed and after compression will
exit through relief 64 in the cylinder as explained
hereinabove. A discharge valve (not shown) located
in main bearing 46 discharges refrigerant into
25 discharge volume 78 defined by discharge muffler 76
and planar portion 50 of main bearing 46~ The
compressed refrigerant will exit from discharge
muffler 76 through three discharge openings 80 in
muffler 76 into sealed housing 10 of the compressor.
30 The refrigerant is discharged directly into motor
windings 23 whereby the windings will be cooled.
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As shown in Figu.re 2, tubes 94 and 96 exit from
the compressor housing and are connected to a desuper-
heater tnot shown) as is well known in the prior art.
Suction tube 34 extends into housing 10 and is sealed
thereto as best illustrated in Figure 1. Suction
tube 34 has a portion 100 extending into an aperture
102 in the wall of cylinder 66. Aperture 102 extends
completely through the cylinder wall and communicates
with bore 92 as best shown in Fig. 2. Tube 34 is
10 sealed to aperture 102 by means of an O-ring 104
housed in an annular recess 106 of the cylinder wall
of cylinder 66. A cylindrical soldering flange 108
secures tube 34 to housing 10 and conducts heat away
from the tube 34 as it is being soldered to the
15 housing. Portion 110 extends away from tube 34 and
is spaced from tube 34 by a space 112 extending
between portion 110 and tube 34. Portion 110 conducts
heat away from tube 34 and into housing 10.
As best illustrated in Figures 5 and 6, crankshaft
20 26 is provided with an axial aperture 114 which
extends completely through the upper portion of the
crankshaft as shown. An aperture 116 extends the
entire length of the lower portion 117 of the crank-
shaft 26 as shown and communicates with aperture 114.
25 The extreme lower end 62 of crankshaft 26, which is
journalled in outboard bearing 56 extends into oil
sump 120 .Located in housing lower shell portion 16.
It should be noted that aperture 116 diverges radially
outwardly of the crankshaft axis in the upward
30 direction so that it angles diagonally upwardly and
its upper portion is spaced radi.ally further outwardly
from the crankshaft axis than its lower portion. As
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oil is drawn up into aperture 116 by the rotating
movement of crankshaft 26, the oil is spun outwardly
by centrifugal force due to the diagonal orientation
of aperture 116. Oil under positive pressure will be
provided by aperture 116 to opening 119 in crankshaft
26 to lubricate roller 86. A radial passageway 122
includes an outer opening 124 which extends into an
annular space 126 surrounding crankshaft 26. Annulus
126 surrounding crankshaft 26 provides a chamber
10 together with relief 127 in outboard bearing 56 for
the oil to flow into under positive pressure from the
pumping aperture 116. The oil will flow outwardly
under positive pressure from annular chamber 126
through passageway 128 as best illustrated in Figure
15 4. Passageway 128 extends radially outwardly in
outboard bearing 56 and conducts oil to an upwardly
extending passageway 130. Passageway 130 has a
relief 132 formed therein which abuts cylinder 66.
As best shown in Figure 1, passageway 130
20 conducts oil under positive pressure upwardly into a
pair of grooves or channels 134 formed on either side
of vane slot 82 in the wall of cylinder 66. Channels
134 are located closer to bore 92 than to the outside
wall 135 of cylinder 66. Oil will be supplied at
25 positive pressure to oil channels 134 and will fill
those channels completely at all times thereby
allowing vane 84 to be well lubricated. Channels 134
are adjacent to and have one side completely open to
slot 82. The column of oil in channels 134 surrounding
30 the vane will prevent refrigerant gas under di.scharge
pressure to escape from the sealed housing enclosure
through vane slot 82 since the oil in channels 134
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forms a hydraulic seal in combination with the vane
84.
By referring to Figure 7 an enlarged broken-away
sectional view of one of the oil channels as viewed
from line 7-7 in Figure 2 can be seen. In cross
section oil channels 134 in the cylinder wall of
cylinder 36 are semicircular as best shown in Figures
2 and 7. The channels or grooves 134 are located
adjacent slots 82 and are open to the slot on one
10 side along their entire axis. Oil can therefore
freely contact both sides of vane 84. Figure 7 also
shows spring pocket 90 and planar portion 60 of lower
bearing 5~ which has a passageway 128 therein from
which oil flows into upwardly extending passageway
130. It can be seen that oil will flow upwardly from
passage 130 past relief 132 directly into the oil
channels 134 from where the oil 136 will exit onto
the top of cylinder 66 as shown into the relief
portion 138 of main bearing 46. The inner wall of
20 cylinder 66 defining the bore 92 is also shown at
140. By placing channels 134 closer to bore 92 than
to the outside of the cylinder wall the oil positively
lubricates the vane portion adjacent to the bore and,
therefore, supplies oil at the point of heaviest
load. Since the refrigerant tends to leak from the
high pressure portion of the housing into the low
pressure side of the cylinder bore, the location of
the channels closely adjacent the bore is desirable
to maintain an adequate oil seal in the leakage
30 clearance. Oil channels 134 are substantially perpen-
dicular to the direction of movement of vane 82.
From relief 138 the oil will flow outwardly and drip
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downwardly around the cylinder and the lower bearing
56 back into the sump 120.
What has therefore been disclosed is a rotary
hermetic compressor wherein oil is pumped from an oil
sump and conducted by positive pressure through a
radial passageway in the outboard bearing and upwardly
axially into a pair of oll channels formed adjacent
the vane slot~ The oil channels will be continuously
filled with oil under the positive pressure from the
10 pumping mechanism, thereby providing proper lubrica-
tion of the vane as well as hydraulic æealing to
prevent refrigerant gas from leaking past the vane.
By properly lubricating the vane, its surface temper-
ature will be minimized. The combination of proper
15 lubrication under positive pressure and hydraulic
sealing increases the efficiency of the compressor
because of a reduction in leakage and the reduction
in the heat e~cchange which takes place in the com-
pressor.
While thls invention has been descrlbed as
having a preferred design, it will be understood that
it is capable of further modification. This applica-
tion is therefore intended to cover any variations,
uses, or adaptations of the invention following the
25 general principles thereof and including such depar-
tures from the present disclosure as come within
known or customary practice in the art to which this
inventlon pertains and fall within the limits of the
appended claims.
