Note: Descriptions are shown in the official language in which they were submitted.
7~D37~ :
SWASH PLATE COMPRESSOR
This invention relates to refrigerant com-
pressors and more particularly to an improved compact
swash plate compressor for air conditioning applications.
It has become an ever increasing requirement . ^
in mobile air conditioniny systems for improved com-
pressors which are reduced in size and weight to enable
vehicles to achieve higher fuel efficiency. An example ..
of a successful compressor presently used in automotive
air conditioning systems is disclosed in U.S. Patent
No. 3,057/545 to Ransom, et al, issued October 10, 1962
and assigned to the assignee of the present appli-
cation. The Ransom et al swash plate compressor, which
is referred to as an axial six compressor in that
it has three double acting axial reciprocatiny pistons,
is an e~icient reliable apparatus but it requires a
sepa:rate oil pump for its lubrication system. Numerous
attempts have been made to provide axial swash plate
compressors with improved lubricatin~ systems which
eliminate an oil pump. An example of such a compressor
is disclosed in U.S. Patent 3,930,758 to Kwang H.
Park, issued January 6, 1976, also assigned to General
Motors Corporation.
Accordingly, it is an object of the present
invention to provide an improved small swash plate
compressor suitable for use in automotive air condi-
tioning systems having a minimum number of parts.
It is another object of the present invention
to provide an improved compact swash plate compressor
of light weight having a lubrication system which
does not require a separate oil pump.
It is still another object of the present
invention to provide an improved open-deck swash plate
compressor, i.e. open space between adjacent cylinder
tubular portions, which achieves a substantial reduction
in weight.
Still another object of the present invention
is to provide an improved axial swash plate compressor
in which lubrication is achieved by a refrigerant flow
path wherein the flow of low pressure .refrigerant gas
from an inlet in one end of the compressor, containing
a substantial amount of entrained oil, enters a
longitudinally extending inlet channel means defined
by the open-deck at a high elevation in the compressor
such that the refrigerant gas and oil mixture is con-
veyed in heat exchange relation with an upper portion
of the cylinder block structure increasing the
temperature of the gas causing sufficient oil to
separate therefrom and deposit on the upper tubular
cylinder block portions for subse~uent gravitational
~7'7Q~7
flow to lubricate portions of the compressor, and
whereby flow oE low pressure refrigerant gas is also
caused to exit the upper inlet channel far delivery
to a swash plate central space prior to being conveyed
to the compressor's cylinders by o~e or more longi-
tudinally extendin~ inlet channels at a low elevation
in the compressor thereby allowing oil mixed with the
gas to envelope and impinge upon and wet the surfaces
of the swash plate mechanism to ensure lubrica-tion of
same during operation of the compressorO
Further objects and advantages of the present
invention will be apparent from the following descrip-
tion, reference ~eing had to the accompanying drawings
wherein two embodiments of the present invention are
clearly shown.
In the Drawinys:
~ig. 1 is a vertical sectional view of one
embodiment of the improved swash plate compressor of
the present invention;
Fig. 2 is a vertical sectional view of the
compressor taken substantially on the line 2-2 of
Fig. 1, showing the rear face of the piston cylinder
block;
Fig. 3 is a vertical sectional view of the
compressor taken substantially on the line 3-3 of
Fig. 1, showing the notched-out portions of the rear
cylinder block;
~'77~
Fig. 4 is a vertical sectional view taken
on the line 4-4 of Fig. 1, showing the rear valve
plate and suc-tion outlet reed valve of the compressor;
Fig. 5 is a vertical sectional view taken
substantially on the line 5-5 of Fig. 1, showing the
inner face of the compressor rear head;
Fig. 6 is a vertical sectional view taken
substantially on the line 6-6 of Fig. 1, showing the
discharge valve arrangement of the subject compressor;
lQ Fig. 7 is an elevational end view taken on
line 7-7 of Fig. 1, showing the rear head of the
compressor;
Fig. 8 is a longitudinal sectional ~iew
taken along the line 8~8 in Fig. 9 of another or
alternative embodiment o~ the improved swash plate
compressor of the present invention;
Fig. 9 is a view ta]cen along the line 9-9
in Fiy. 8 with the upper two cylinder bores orientecl
parallel to each other;
Fiy. 10 is a view oriented like Fig. 9 and
taken along the line 10-10 in Fig. 9;
Fig. 11 is a view oriented like Fig. 9 ancl
taken along the line 11-11 in Fig. 8;
Fig. 12 is a view oriented like Fig. 9 and
taken along the line 12-12 in Fig. 9;
Fig. 13 is a view oriented like Fig. 9
and taken along the line 13-13 in Fig. 9;
Fig. 14 is a view taken along the line 14~14
in Fig. 11;
Fig. lS is a view taken along the line 15-15
in Fig. 13;
Fig. 16 is a view oriented like Figure 9
and taken along the line 16~16 in Fig. 8;
Fig. 17 is a view oriented like Fig~ 9 and
taken along the line 17-17 in Fig. 8;
Fig. 18 is a view oriented like Fig. 9 and
taken along the line 18-18 in Fig. 8;
Fig. 19 is a view orlented lika Fig. 9 and
taken along the line 19-19 in Fig. 8;
Fig. 20 is a view oriented like Fig. 9 and
taken along the line 20~20 in Fig. 8;
Fig. 21 is an enlarged partial view o one
of the piston heads in Fig. 18 showing the assembly
of the ring thereon;
Fi~. 22 is an exploded view of one of the
pistons and its rings ~rom t:he refrigerant compressor
in Fig. 8; and
Fig. 23 is an exploded view of the refriger-
ant compressor in FigO 8 excluding the pistons.
Referring now to the drawings wherein two
embodiments of the p~esent invention have been disclosed
and firs-t with respect to the embodiment in Figs. 1-7,
reference numeral 10 in Fig. 1 designates a swash
~7~3~
plate axial compressor which is adapted to be driven
by suitable drive means, such as a magnetic clutch
assembly (not shown) sui-tably mounted on neck portion 11.
Reference numeral 12 designates an outer
shell element which is cylindrical in shape and serves
to support a pair of front and rear cylinder heads 14
and 16 respectively which close the opposite ends of
the shell 12 as shown. A swash plate 18 is fixedly
mounted on a compressor drive shaft 20 which shaft
is rotatably supported by front 22 and rear 2~ journal
bearings mounted in the front 26 and rear 27 central
hub portions integrally formed with fron-t 28 and rear
30 cylinder blocks, respectively. Rotation of the
drive shaft 20 is trans~ormed into reciprocal motion
of three double-acting pistons indicated at 31, 32
and 33 in Fi~. 2. As seen by lower double-acting
piston 33 in Fi~. 1, each of the pistons are arranged
to reciprocate in a direction parallel to the axis
of the drive shaft by means of being slidably disposed
in opposed front 31', 32', 33' and rear 31''~ 32''
33'' piston cylinder bores of the front 28 and rear 30
cylinder blocks, respectively.
The rotation of the drive shaft 20 is trans-
formed into reciprocal motion of the double acting
pis-tons 31, 32 and 33 through sliding members which
in the disclosed form are half-sphere bodies 36. As
~7~3~
seen in Fig. 1 for piston 33 each of the pistons
has a central part of its one side cut~away so as to
straddle the outer edge of the swash plate 18. Bowl-
shaped recesses 38 are formed on the cut-away portions
of the pistons with the half-sphere sliding bodies 36
journaled within the bowl shaped recesses 38 in opposed
relation with the flat sides of the bodies cooperating
with the planar surfaces 39 of intermediate swash plate
18. By virtue of the bearing construction shown in
Fig. 1, the piston pumping loads are taken both by the
front 22 and rear 24 radial or ~ournal needle bearings
and front 40 and rear 42 needle thrust bearings.
Individual front 44 and rear 46 valve plates
are mounted between the front 14 and rear 16 heads
and their associated front ~8 and rear 30 cylinder
blocks. As seen in Figs. 1 and 4, the valve plates
44, 46 are formed with suction inlet and discharge
outlet ports 47 and 48 respectively, in registry with
each front 31', 32l, 331 and rear 31'`~, 32 ", 33''
2Q cylinder. Each valve plate is provided with a suction
reed valve 50 on its inner face and discharge reed
valves 52 and 53 ~Fig. 6) on its outer face as is
well known in the prior art. Backup valve retainers
or stops 54 and 55 are provided for their assoc:iated
discharge reed valves 52 and 53 respectively, to
prevent excessive deflection thereof. Each suction
~77~3~
inlet port 47 provides communication between its
associated pumping cylinder bore and front 56and rear
58 head outer low pressure gas suction cylindrical
chambers, as seen at 58 in Fig. 5 for the rear head 16
outer suction chamber. Each discharge or outlet port 48
provides communication between the pumping cylinder
bores and front 60 and rear 62 head high pressure gas
inner discharge chambers, as seen in Fig. 5 for the
rear head inner chamber 62. It will be noted that
O-ring seals 63 in the front and rear valve plates
separate the outer suction chambers 56, 58 from the
inner discharge chambers 60, 62 respectively.
The fron~ and rear cylinder heads 14 and 16
each have intermediate and outer concentric closed
annular loops or ribs 64, 65 and 66, 67 respectively,
defining the fronk 56 and reclr 58 heacl low pressure
outer suction chambers which communicate with their
associated three suction gas inlet ports 47. As
seen in Fig. 5, the rear head 16 has a circular suction
gas upper inlet bore or opening 70, symmetrical with
the vertically extending plane defined by construction
line "X" of Fig. 5. The op~ng 70 extends through integral boss
72, cc~m~nicating first with a near rectangular shaped aperture 73,
defined between the intermediate 66 and outer 67 annular ribs
and vertical interconnecting partitions 74 and 75 positioned in
parallel equidistant relat.ian on ei-ther side of the construction
line "X". Rear valve plate 46 includes an upper opening 76
~7~'13~
shaped-to align with the near rectangular shap~d aperture 73. ThuS,
the suction gas to be compressed is admitted, via aligned rear head
inlet openinc~ 70~ rear Yalve plate opening 76 arld aperture 73, into
!l a low pressure refrigerant gas upper inlet channel
or suction passage 77.
As best seen in Figs. l and 3, the front
28 and rear 30 cylinder blocks are located in flush
aligned engagement by a pair of alignment or Iocating
pins (not shown) along a transverse parting surface
lO indicated at 80 in Fig. l. Similar pairs of alignment
pins, shown at 82 in Figs. 2, 4 and 5, properly locate
the valve plates and compressor heads by insertion
in locating holes. Thus, the inlet channel 77 is formed
by the front cylinder block 28 upper tubular portions
1.5 l-F and 2-F, the corresponding abutting reax cylinder
block tubular portio~ l-R and 2-R (Fiy. 3) defining,
with the outer shell 12, the low pressure re~rigerant
gas upper inlet channel 77. In a similar manner the
front l-F and rear 1-R pair of upper tubular portions
20 define with the ront 3-F and rear 3-R pair o~
lower tubular portions and the shell 12, a ~irst
low pressure reErigerant gas lower exit channel
or suction passage 78. Lastly, the ront 2-F and
rear 2-R pair of upper tubular portions define, wi-th the
front 3-F and rear 3-R pair of lower ~ubular portions
and the shell 12, a second low pressure refrigerant
gas eY~it channel or suction passage 79O
,t~ 3
Each of the front and xear opposed tubular
portions of the cylinder blocks has its pair of ront
and rear cylinder bores axially separated in part by
a substantially one-half or semi-cylindrical radially
inwardly-facing notched-out opening.or cavity. Thus, as
seen in ~ig. 1, the ~ront upper tubular portiQn 2-F has an
inner notched-out portion 92 in mirror image relation
to the notched-out portion 94 of the rear upper tubular
portlon l-R. In this manner the three one-half cylin-
drical notched-out openings of the opposed tubular
portions l-F, l-R; 2-F, 2~R; and 3-F, 3-R together
with the opposed inner faces of the front 26 and rear 27
hubs define a central swash-pla-te accommodating space 100.
Thus, in operation the total flow of rela-
-tively low pressure, low temperature suction gas entering
the rearward end of the upper inlet channel, containing
a subs-tan-tial amounk of oil in suspens.ion, flows
axially in heat exchange relation over the heated
upper surfaces 102 and 104 of the upper tubular portivns
2Q l-R, l-F, 2-R and 2-F. The increased temperature of
the refrigerant gas causes a portion of the entrained
oil to separate from the gas and deposit by gravity
on the upper tubular portions. The lubricant or oil
collected on the surfaces 102, 104 is subjected to
the heat of the compressor cylinder blocks and the
refrigerant dissolved therein is driven-off or "flashes-
off" by this heat. The substantially refrigeran-t-
free lubricant or oil thus deposited subsequently
~77~3~
11
moves by gravitational flow downwardly via slot means
106 and 108 on the front and rear hub inner faces to
lubricate the front 22 and rear 24 journal means, and
front 40 and rear 42 thrust bearing means.
Further, the total flow of low pressure
refrigerant gas is caused to exit the upper inlet
channel 77 via the upper tubular portion notched-out
openings 92, 94 (Fig. 3) for delivery or flow
to the swash-plate central space 100 prior to being
drawn or conveyed into the pair of lower exit channels
78 and 79. The result is that sufficient of the -
remaining oil admixed with the ~as impinges upon and
wets or "fogs" the surfaces 39 of the swash plate 18
to provide lubrication ~etween the swash plate and the
half-sphere shoes or bodies 36 during reciprocation
of the dual-acting pistons.31, 32 ancl 33.
As best seen in Figs. 2 and 3, lower channel
outlet means are provided on the front 44 and rear 46
valve plates. In the form disclosed the outlet means
are pairs or sets of holes 112, 113 and 114, 115
in -the front valve plate 44 and pairs or sets of holds
116, 117 and 118, 119 in the rear valve plate 46.
By means of these paired holes, aligned with their
associa-ted lower exit channel, the total flow low
presure gas flows from the swash plate space 100 and
divides into the two lower exit channels 78 and 79.
As seen in Fig. 4 for rear valve plate paired holes
11
~ ~t77~3~
116, 117 and 118, 119, the holes are aligned into
each of their associated lower exit channels 79 and 78
respectively to provide communication to both the ront
and rear head outer suction annular chambers 56 and
58 for introduction of the gas into their associated
front and rear cylinder bores.
The compressed gas is discharged into both
the front and rear cylinder head central discharge
chambers 60 and 62. Thereafter the discharge chambers
are connected by means of a discharge gas crossover
tube 120, the front end of which is telescoped in
opening 122 in the f~ont valve plate and sealed by
O-ring 124. In a similar manner the rear end of tube
120 is telescoped in opening 1.26 in -the rear val~e
plate and sealed by O-ring 128. Thus, the compressecl
refrlgerant gas travels from front chamber 60 via
tube 120 into rear chamber 62 and leaves the compressor
through a rear head outlet aperture 130.
~n the form shown the compressor is assembled
by forming the outer shell front end with a rolled
front edge 132 such that the sub-assembly of the
compressor heads, blocks, valve, plates, etc. is
telescopically received in the open threaded end 134
of the shell. The assembly is then closed in a sealed
manner by front and rear head O rings 136 a.nd 138
and torqued together by ring nut 140.
12
~7'7~
13
Another achievement of applicants' unique
compressor is in its substantial reduction in weight
over prior art axial compressors. The arrangement
provides cylinder heads 14 and 16 which partially
form the pair of radially outer suction cavities or
chambers 56, 58 and the pair of radially inner
discharge cavities or chambers 60, 62 flanking the
compressor crankcase formed by shell 12. The fron-t 28
and rear 30 cylinder blocks and their associated three
composite tubular portions define a composite ~ri-
furcated cylinder block including three tubular portions
arranged about an axis toprovide open space between
ajdacent pairs of the tubular portions, thereby to
reduce the weight of said cylinder block.
The other or preferred embodiment o the
present invention shown in Figs. 8-23 is utilized to
advantaye in an integral shell and cylinder block
form of compressor construction comprising a plurality
of die cast aluminum parts; namely, a front head 210,
a front cylinder block 212 with integral cylindrical
case or shell 214, a rear cylinder block 216 wi-th
integral cylindrical case or shell 218 and a rear
head 220. ~s can be seen in Figs. 8 and 23, the
front head 210 has a cylindrical collar 221 which
telescopically fits over the front end of the fron-t
cylinder block shell 214 with both a rigid circular
13
P3~
14
front valve pl~te 222 of steel and a circular ~ront
valve disk 223 o~ spring steel sandwiched there-
between and wlth an O-ring seal 224 provided at their
common juncture. Similarly, the rear head 220 has a
cylindrical collar 225 which telescopically ~its over
the rear end of the rear cylinder block shell 218
with both a rigid circular rear valve plate 226 o~
steel and a circular rear valve disk 227 of spring
steel sandwiched therebetween and with an O-ring
seal 228 providing sealing a-t their common juncture.
Then at the juncture of the cylinder blocks, the rear
cylinder block shell 218 has a cylindrical collar 229
at its front end which telescopically its over the
rear end of the front cylinder block shell 21~ and
there ls provided an O-ring seal 230 to seal this jolnt
in the transversely split two-piece cylinder bloc]c
thus formed.
All the above metal parts are clamped together
and held by six (6) bolts 231 at final assernbly a~ter
the assembly therein of -the internal compressor
par~s later described. The bolts 231 extend through
aligned holes in the front head 210,valve plates 222,
226 and valve disks 223, 227 and elther alignment
bores and/or passages ln the cylinder blocks 212, 216
(as described in more detail la-ter) and are -threaded
to bosses 219 ormed on the rear head 220. The heads
210 and 220 and cylinder block shells 214 and 218
14
~ ~.7~7~3~
have generally cylindrical profiles and cooperately
provide the compressor with a generally cylindrical
proile or outline of compac-t siæe characterized by
its short length as permitted by the piston and piston
ring structure described in detail later.
The front and rear cylinder blocks 212 and
216 each have a cluster of three equally angularly
and radially spaced and parallel thin-wall cylinders
232(F) and 232(R), respectively (the suffixes F and R
being used herein to denote front andrear counterparts
in the compressor). The thin-wall cylinders 232(F).
and 232(R) in each cluster are integrally joined along
their length with each other both at the center of
their respective cylinder bl~ck 212 and 216 and at
their respective cylinder block shell 14 and 18 as
can be seen in Fi~s. 9 a~d 10. The respective front
and rear cylinders 232(F) and 232(R) each have a
cylindrical bore 234(F) and 234(R) all of equal
diameter and the bores in the two cylinder blocks are
a~ially aligned with each other and closed a-t their
outboard end by the respective front and rear valve
disk 223 and 227 and valve plate 222 and 226. The
cylinder blocks each have a hollow opening at their
juncture such that oppositely facing inboard ends of
the aligned cylinders 232(F) and 232(R) are a~ially
spaced from each other and together with the remaining
~L'7~7~3~7
16
inboard end details of the cylinder blocks 212 and
216 and the interior o~ their xespective integral
shell 214 and 218 form a central swash plate accom-
modating crankcase cavity or space 35 in the compressor
extending transversely thereacross to the internal
periphery thereof as in the Figs. 1-7 embodiment
thereby fully exposing both sides of the swash plate.
In wha-t will be referred to as the normal or in-use
orientation of the compressor, the three pair of
aligned cylinders are located as seen in Figs. 9
and 10 at or close to the two, six and ten o'clock
positions with the two adjoininy upper cylinders in
each cylinder block designated 232(A) and 232(B)
and the lowermost cylinder desiyna-ted 232(C).
~ symmetrical double-ended piston 236 of
aluminum is reciprocall~ mounted in each pair o~
axially aligned cylinder bores 234(F), 234(R) with
each piston having a shor-t cylindrical front head
238(F) and a short cylindrical rear head 233~R) of
equal diameter which slides in the respecti-ve front
cylinder bore 234(F) and rear cylinder bore 234(R).
The two heads 238(F) and 238(R) of each piston are
joined by a bridge 239 spanning the cavity 235 but
are absent any sled runners and instead are completely
supported as well as sealed in each cylinder bore by
a single solid (non-split) seal-support ring 240
~77~3~
mounted on each piston head with such piston structure
and the support and sealing arrangement therefor
the same as shown in the Figs. 1-7 embodiment and
as described in more detail later.
The three pistons 236 are driven in conven-
tional manner by a rotary drive plate 241 located in
the central cavity or space 235. The drive plate 241,
commonly called a swash plate, drives the pistons
from each side through a ball 242 which fits in a
socket 244 on the backside of the respective piston
head 238 and in a socket 246 in a slipper 248 which
slidably engages the respective side of the swash
plate. The swash pla-te 241 is fixed to and driven
by a drive shaft 249 that is rotatably supported and
axially contained on opposite sides of the swash plate
in the two-piece cylinder block 212, 216 by a bearing
arrangement including axially aligned front and rear
needle-type journal bearings 250(F), 250(R) and front
and rear needle-type thrust bearings 252(F), 252(.R).
The .front journal bearing 250(F) and rear
journal bearing 250(R) are mounted respectively in a
central bore 254 in the front cylinder block 212 and
a central bore 256 in the rear cylinder block 216
and it is important that these bores, like the cylinder
bores in the blocks, be closely aligned with each
~77~rl~
18
other. ~he front thrust bearing 252(F) and rear thrust
bearing 252(R) are mounted respectively between an
annular shoulder 258, 260 on the respective ~ront
and rear side of hub 262 of the swash pla-te 241 and
an annular shoulder 264, 266 on the respective inboard
end of the front and rear cylinder blocks 212, 216.
The rear end 268 of the drive shaft 249 terminates
within the rear cylinder block shaft bore 256 which
is closed by the center of the rear valve plate 226.
On the other hand, the drive shaft 249 extends outward
of the front cylinder block shaft bore 254 through a
central hole 270 in the front valve plate 222 and thence
on outwardly through an aligned hole 271 in a tubular
extension 272 which projects outwardly from and is
integral with the front head 210.
As shown in Fig. : 8, a rotary seal assembly
274, including a stationary seal 275 and a spring
biased rotary seal 276 that enyages ther~with~ provides
sealing between the drive shaft 249 and front head
210 within the tubular ex-tension 2720 Outboard this
seal arrangement -the drive shaf-t 249 is adapted to
be secured with ~he aid of a thread 277 on the end
thereof to a clutch of conventional type, not shown,
which is engageable to clutch the shaft to a pulley,
also not shown, which is concentric therewith and in
the case of vehicle installation is belt driven from
18
~7t7~3~
19
the engine. For mounting the compressor, three
mounting arms 278 are integrally formed wi-th the ~ront
head 210.
The heads ~38(F), 238(R) of the pis-tons 236
are extremely short and without sled runners and are
provided with a diametricaldimension less than the
diametrical dimension of their cylinder bores 234(F),
234(R) to provide a space therebetween enabling the
seal-support ring 240 between each piston head and
its respective bore to be made sufficiently thick
so that it provides full radial support of the pist~n
head within its cylinder bore as well as sealing with
the metal of the piston head then not allowed to touch
the metal of its respective cylinder bore throughout
its reciprocation therein. See ~ig5. 8 and 21-23.
Each plston head 23~(F), 238(R) is provided with a
sufficiently short loncJitudinal or axial dimension
along its bores so as to produce a sufficient circum-
scribing area on the piston head in juxtaposition with
the bore to permit the wear resistance of the seal-
support rings 240 to approximate the life of the com-
pressor while the weight of the piston head is reduced.
In addition, the pistons have essentially only sufficient
material in their bridge 239 to hold the piston
heads together during reciprocation so that the
weight of the piston is further reduced. Wi-th such
19
Lt7~3
piston weight reduction, the mass of the swash plate 241
is then reduced by thinning thereo~ in proportion to
such reduction in the piston while still providing
dynamic balancing thereo~. The above dimensional
reductions in turn allow compacting of the compressor
outline in the longitudinal or axial direction.
For example, in an actual constructuion of the c~mpressor
disclosed herein ~not including clutch) having a total
displacement of about 164 cm3, it was found that its
barrel diameter and lenyth could be made as small as
about 117 mm and 160 mm respectively and its weight
as little as about 3,6 kg.
The pistonsl solid seal support rings 240
are made of a slippery material such as Teflo~ or the
like and are each mounted in a circumfe~ential groove
370(F~, 370(R) in the respective pistons heads 23B~F?~
238(R~ of each piston 236. The piston seal-suppor~
rings 240 are provided with a nominal unstressed thick-
ness dimension slightly greater than the width of the
radial space between the p.iston head and its respective
bore and are provided with a nominal unstressed
longitudinal or axial dimension slightly less than
the longitudinal or axial dime~sion of the piston
head. The two remaining lands 372(F), 374(F~ and
372(R), 374(R) on each of the respective piston
heads 238~F), 238(R) that are on opposite sides of
the seal~support ring 240 are extremely thin as
~77q~
permitted by their relief from side loading and thus
each of the pistons 23~ is free to tilt or angle
slightly with respect to the paired-cylinder bores
therefor. This reduces significantly the criticality
of the axial alignment of these bores and thereby
increases subs-tantially their manufac-turing tolerance
further enabling individual boring of the front and
rear cylinder blocks rather than as an assembled pair.
With the pistons 236 thus completely supported
19 in their bores by the solid (non-split) seal-support
rings 240, the pistons maythen move axially and radially
relative to their rings and also in a back and forth
rolling sense about the piston's centerline. ~s
to the relative axial movement, this results from end
lS play between the ring and its groove which cannot
normally be avoided except by selec-tive fit because
of manufacturiny tolerances. As to the relative
radial movement, this results from the drive engagement
between the pistons and the swash plate. As to the
relative rolling movement, this results from the clearance
between the bridge 239 of the pistons and the periphery
of the swash plate 241 as can be seen in Fig. 8
and 10. This relative piston groove and seal-support
ring movement or rubbing can wear the ring groove
deeper thereby adversely affecting seallng as well as
wear the flat annular face o~ the groove shoulders
21
~77~37
at the piston head lands 372 and 374 thereby adversely
affecting ring retention and thus again sealing. Such
problems are positively avoided bv manufacturing (as
by cutting) the rings 240 in the shape of a slightly
concave washer as shown in ~ s. 21 and 22 and to a
certain size in relation to the diameter of the cylinder
bores and the bottom of thepiston ring grooves and by
forming radially outwardly extending projections on
the bottom of the ring grooves that will then positively
interfere with relative ring and piston movement in both
the longitudinal and roll direction. As to the formation
of suitable projections on the bottom of the ring grooves
this is accomplished by simply knurling or stenciling
the bottom of each groove 370 so as to form a series
of raised X's or crossbars 376 spaced thereabout with
the raised bars or ridges of each at opposite anyles
to the pistons' longitu~inal direction or centerline.
The inner diameter (I.D.) of the rings 2~0 in the as-
manufactured state (washer shape) is made sufficien-tly
small so as to pass with the concave side first over
the end land 372 of -the piston head with the ring
under elastic stress across substantially the entire
width thereof (see Fi~.. 21). This provides each
ring with an expanded fit over the end lands 372
across substantially its entire width af-ter which
the ring contracts within -the piston ring groove 370
22
!3~
with its opposite annular sides or faces 240(A)
and 240(B) then assuming inner and outer cylindrical
surfaces and with substantial radial pressure existing
between the bottom of the piston ring groove 370 and
the opposing inner cylindrical side or face 240~B)
of the ring. With such rings 240 thus assembled on a
piston 236, the rings are then radially inwardly
compressed such as by passing such piston and ring
assembly through a cone so that their outer diameter
at side 240(B) is reduced to a dimension equal to or
slightly less than the diameter of -the cylinder
bores 234. The piston 236 with the thus squeezed rings
240 thereon is assembled in its cylinder bores 234(F),
234(.R) before the memory of the ring material causes
the rings to recover to their oriyinal thickness.
Then with their memory recoveriny in the cylinder bores,
the rings 240 thereby expand to e.efect tight seal.ing
engagement therewith as well as prevent relative radial
movement between the annular shoulders of the piston
ring grooves 370 and the annular edges of the rings
in support of the piston head in its cylinder bore.
In addition, this piston ring groove and ring relation-
ship and assembly in the cylinder bores causes the
raised projections 376 on the bottom of each piston
ring groove 370 to bite or imbed into the inner cylin-
drical face 240(B) of the rings 240 mounted thereon
23
~'7~ 3~
24
under the contractural force o~ the ring ~nd the
retained compression thereof by its respective cylinder
bore. Thisbite or imbedment is determined to a degree
sufficient to anchor the piston against both rotational
and longitudinal sliding movement relative to the ring
and be maintained by the radial containment of the
ring by the cylinder bore in which it slides. Thus,
the pistons 236 and their rings 240 are positively
prevented from rotating or sliding relative to each
other and thereby causing rubbing wear therebetween.
For example, in an actual construction of the com-
pressor disclosed herein, it was found that the above
improved results were obtained with cylinder bores of
about 38.1 mm when the piston ring yroove bottom
diameter Dl70 and land diameter D172,174 were m
about 36.6 mm and 37.9 mm, respectively, the projections
376 were provided with a heicJhth of 0.05-0.10 mm
max., and the seal-support rings 240 in the pre~
assembly state (washer shape) was then provided with
a thickness of about 5.8 mm and an inner and outer
diameter of about 28.5 mm and 40.1 mm, respectively.
Describing now the refrigerant flow system
within the compressor in Figs. 8-23, gaseous refrigerant
with some oil entrained therein enters through an
inlet 280 in the rear head 220 and into a cavity 282
in the rear head as can be seen in Figs. 15 and 16.
24
~7~
The enterin~ xefrigerant is directed through the rear
cavity 282 through a rectangular shaped aperture 284
in the rear valve plate 226 and a corresponding aper-
ture 285 in the rear valve disk 227 into a xefrigerant
transfer and oil separation cavity arrangement or
suction passage 290 which extends the length of the two-
piece cylinaer block 212, 216 and opens intermediate
its length to the central crankcase cavity or space
235 accommodating the swash plate 241 as in the
Figs. 1-7 embodiment. The longitudinally extendin~
refrigerant transfer and oil separation passage 290
is defined again by certain internal structure of the
compressor so as to induce oil separation from the
passing refrigerant for lubrication of the compressorls
working parts. This oil separation structure prima:rily
includes the adjoining longi.tudinally extending outer
convex surface 291(F), 292(Fl and 291(R), 292(R)
of the two adjoining upper cylinder walls 232(A),
232(B) of the respective front and rear cylinder blocks
212, 216 and by, but only secondarily, the longitudinally
extending interior concave surface 294(F), 294(R) of
the respective front and rear cylinder block shells
214, 218.
The refrigerant transfer and oil separation
passage 290 is open in the front end of the compressor
through a rectangular shaped aperture 295 in the
26
~ront valve disk 223 and a corresponding aperture 296
in the front valve plate 222 to an annular front
suction chamber 298 in the front head 210 located
around the internal periphery thereof as in the
Figs. 1-7 embGdiment. The front suction chamber 298
is formed by the inboard side of the front head 210
and an external and internal cylindrical wall 299,
300, respectively, extending inboa;rd therefrom and by
the outboard side of the front valve plate 222. The
front suction chamber 298 is connected to a crossover
suction passage 301 extending longitudinally within
the compressor between the cylinder walls 232(~)
and 232(C) as is a rear suction chamber 302 in the
rear head 220 like in the Figs. 1-7 embodiment. The
front suction chamber 298 is open to the crossover
suction passage 301 throuyh an oblong aperture 303
in the front valve plate 222 (see FicJs. 17 and 23)
and a pair of circular apertures 304 in the front
valve disk 323 (see Figs. 18 and 23). The suction
crossover passage 301 extends the length of the two-
piece cylinder block 212~ 216 and opens intermediate
its length to the swash plate accommodating space 235
across the swash plate from the opening thereto o the
refrigerant transfer and oil separation passage 290
as in the Figs. 1-7 embodiment and is formed by the
ad~oining longitudinally extending outer convex
26
3L~7~3~'
surface 305(F), 306(F~ and 305(,R~, 306tR~ of the two
adjoining cylinder walls 232(A), 232(C~ of the res-
pective front and rear cylinder blocks 212, 216 and
by the longitudinally extending interior concave sur-
face 307(F~, 307(R) of the respective cylinder blockshells 218, 214. The crossover suction passage 301
at the rear end of the compressor is open to the rear
suction chamber 302 through a pair of circular aper-
tures 308 in the rear valve disk 227 (see Figs. 12 and 23)
and an oblong aperutre 309 in the rear valve pla-te 226
(see Figs. 11 and 23). The two suction chambers 298
and 302 are adclitionally connected to the,,wash plate
accommodating space 23S and thereby to the refrigerant
transfer and oil separation passage 290 by another
crossover suction passageway extendiny be-tween the
cylinders as in the Figs, 1-7 embocliment as wi].l be
described in more detail later. As can be seen in
Figs. 8, 15 and 16, the rear suction chamber 302 is
located around the internal periphery of the rear head
as in the Figs. 1-7 embodiment and is a partial or
split annulus by separation of the inlet cavity 282
and is formed by the inboard side of the rear head 220
and an external and internal partial cylindrical wall
310, 311, respectively, extending inboard therefrom
and by the outboard side o -the rear ~alve plate 226.
The refrigerant received in the respective
front and rear suction chamber 298, 302 which is
27
~7'7~3~
primarily from the crankcase cavity 235 is admitted
to the piston head end of the respective cylinder
bores 234(F), 234(R~ through separate suction ports
312(F), 312(R) in the respective fron-t and rear valve
plates 222,227 (see Figs. 11, 12, 17, 18 and 23).
Opening of the suction ports 312(F), 312(R) during
the respective piston suction stroke and closing
during the piston discharge stroke is effected by
separate reed-type suction valve 314(F), 314(R) on
the piston side of the valve plates w~hich are formed
in the front valve disks 223 and rear valve dis~ 227
respectively (see Figs. 12 and 18).
Then for discharge of the refrigerant upon
compression thereof in the cylinders, there are formed
separate discharge ports 315(F), 315(R) in the res-
pective valve plates 222,226 with these discharge
ports located at the piston end of -the respective
cylinder bores 234(F), 234(R) and open thereto through
oblong apertures 316(F), 316(R) in the respective
valve disks 223, 227 (see Figs. 11, 12, and 17, 18)~
Opening and closing of the respective discharge ports
315(F), 315(R) is effected by separate reed-type
discharge valves 317(F), 317(R) of spring steel
which are backed up by rigid retainers 318(F), 318(R).
The discharge valves 317(F), 317(R) and their
respective re-tainers 318(F), 318(R) are each fixed
28
3 ~
29
as seen in Figs, 11, 1~, 17 and 23 by an integral
pin and blind hole interlock 319 and a rivet 320
to the outboard side of the front valve plate 222 and
rear valve plate 226 respectively and it will be noted
that the discharge valves and retainers for the two
upper cylinders in each cylinder block are of siamesed
construction. -
The respective discharge ports 315(F), 315(R)
are openedby their discharge valves 317~F~, 317(R)
to an annular discharge chamber 320, 322 in the respec-
tive front and rear heads 210 and 220. The front
discharge chamber 320 is formed by the inboard side
of the front head 210 and the interior cylindrical
wall 300 and an inboard projecting extension 32~ o~
the tubular portion 272 of the front head and by the
outboard side of the fron-t valve plate 222. The
inwardly projecting annular e~tension 32~ on the front
head 210 engages and thereby braces the center of
the front valve plate 222 about the drive shaft 249.
An O-ring seal 326 is mounted in a circular groove in
the outboard side of the front valve plate 222 and is
engaged b~ the flat annular radial face of -the
interior cylindrical wall 300 of the front head to
provide sealing between the front suction chamber 298
and front discharge chamber 320. At the opposite or
rear end of the compressor, the rear discharge chamber
29
322 is formed by the inboard side o~ the rear head 220,
the interior cylindrical ~all 311 of the rear
head and a central boss 330 e~tending ~rom the inboard
side o~ the rear head and by the outboard side of
the rear valve plate 226. An O-ring seal 332 is mounted
in a circular groove in the outboard side of the rear
valve plateand is engaged by the flat annular radial
face of the interior wall 311 of the rear head to
provide ~ealing between the rear suction chamber 302
and rear discharge chamber 322. The central boss 330
engages and thereby braces the center of the rear
valve plate 226 and in addition has a conven-tional high
pressure relief valve 336 threaded thereto. The
relief valve 336 is open to thedischarge chamber 322
through a central axial bore 337 and a radial port
338 in the boss 330 to provide high pressure relief
operation. In addition, there is formed a port 339
in the rear head 220 that is open to the rear discharge
chamher 322 and is adapted to receive a conventional
pressure switch, no-t shown.
The discharye chambers 320 and 322 in the
opposite ends of the compressor are connected to
deliver the compressed refrigerant in a pulse attenu-
ated state to ~n outlet 340 in the rear head 220
which opens directly to the rear discharge cham~er 322.
This pulse attenuated state is accomplished b~
~77Q~37
31
eonneetion o~ the two discharge chambers320, 322
throu~h two lar~e volume attenuation ehambers 3~8 -.
and 350 which are ormed in the outboard end of the
respecti~e cylinder bloeks 212 and 216 between their
eylinder walls 232(B~ and 232(C) and are intereonneeted
by a long, small-flow-area attenuation passage 352
formed by a matehing bore 354(F?, 354(R) in these
respeetive eylinder bloeks (see Figs. 8-12, 17, 18
and 23). As best seen in Figs. 8-10 and 23, two
radially and longitudinally extending partitions 350(F) (B),
355 (F) (C) and 355tR) (B) r 355 (R) (C) in the respective
front and rear eylinder bloeks 212, 216 togethex with
the respeetive integral shells 214 and 218 define
the peripheral wall of the re.speetive attenuation
ehambers 348, 350. These partitions separate the
ehambers 348 and 350 ~rom the two bolts 231 which
extend with clearance through the remaining cavities
in the cylinder blocks between their cy].inder walls
232(B) and 232(C) and through their aecommodating
2Q holes in the valve plates and valve disks to thereby
form additional longitudinally extendiny crossover
suetion passages 301(B? and 301(C? connecting the
suction chambers 298 and 302 with the suction passage 290
via the swash plate accommodating space 235. Connection
is then provided directly between the diseharge
chambers 320, 322 and the respective attenuation
31
~ 3t~
chambers 348, 350 by a transfer port 356(F), 356(R)
in the respective valve plates 222, 226 and a corres-
ponding aperture 357(F~, 357t~) in the respective
valve disks 223~ 227 (see Figs. 11, 12 and 17, 18).
As a result, the discharge gas pulses from each of
the cylinders at the opposite ends of the compressor
first experience a large chamber (i.e. their respective
discharge chamber 320 or 322) and are then permitted
to be transmitted in restricted manner through a
small port (i.e. port 356(F) or 356(R)) to a first
attenuation chamber (i.e. chamber 348 or 350) and
thereafter through a long passage of restricted size
(i.e. passage 352) and thence into a second attenuation
chamber (i.e. chamber 350 or 3~3) and eventual:Ly
to the other discharge chamber (i.e. dischar~e chamber
322 or 320). The three di..scharge pulses emitted ~rom
the cylinders at each end of the compressor are out
of phase with each other but in phase with those at
the opposite end and it has been found that by pre-
scribing a certain relationship between the volumeand length of the attenuation chambers and the flow
area and length of the passage connecting them, the
above internal gas discharge network in the compressor
operates to substantially attenuate the gas pulses
issuing from the compressor at the outlet 340 to the
extent that no external or auxiliary muffler is required.
32
3~
For example, in an aetual eonstruetion o~ the compressox
diselosed herein having a total displacement of about
164 em3, it was found th.at wi.th the volume and len~th
of eaeh attenuation ehamber 348, 350 made about 12,3 cm
and 30 mm respeetively, and the flow area and len~th
of the eonneeting attenuation passage 352 made ~bout
40 mm and 49 mm, respectively, no objectionable
vibrations were observed at a conventional eondensex
and/or e~aporator served by the eompressor,
The attenuation bores 354(F), 354~R~ which
align with eaeh other to form the passa~e 352 inter-
eonneeting the attenuation ehambers 348 and 350 also
eontribute signifieantly in simplifying khe manu~acture
of the two eylinder block.s 212 and 216 by permittiny
their proeessing as separate pieees on an assembly
line rather than perfecting marriage between two
partieular eylinder blocks and having to then proeess
both on down the line. This is aeeomplished by
first loeating and boring the bore 354(F), 354(R)
in each cylinder block on the assembly line and then
locating off this bore at the various work s-tations,
such as with a locator pin, for all further processing
of this part. As a result, it is possible to accurately
locate and then machine the eylinder and shaft bores
and other eritieal details in eaeh eylinder bloek
pieee with automatic equipment so that they have the
33
~7~7~3~
34
required close alignment with their counterpart(s~
or other associated structural details in any other
cylinder block piece. This accurate cylinder block
alignment ~s then positively established and main~
tained at final assembly by two of the six bolts 231
designated as 231(A) and 231(B) which are located
generally opposite each other relative to the compressor
centerline. The two bolts 231(A) and 231(B) are the
only bolts that are required to fit, and closely so,
with matching holes 358~F), 358(R) and 359(F), 359(R)
that are accurately located off of the respective
locator bores 354(F), 354(R) and bored in internal
bosses in the respective cylinder blocks 212 and 216
(see Figs. 9, 10 and 23).
The compressor in Figs. 8-23 has no oil
lubricating pump mechanism as such and instead has a
passive lubrication system as in t~e Figs. 1-7 embodiment
which separates out and strategically deploys the oil en-
trained in the entering refrigerant to lubricate all of
the compressor's internal sliding and bearing suraces.
Describing then and comparing the two embodiments of
the present invention they each provide for lubrication
of a compressor having a swash pla-te 18 (241) that
is rotatably supported and axially contained between
a pair of end-to-end joined cylinder blocks 28, 30
(212, 216) by a journal bearing 22, 24 (250 F, R)
34
~.~7 7~
and a thrust bearing 40, 42 (252 F, R) on opposite
sides o~ the swash plate wherein the swash plate sides 39
are in sliding drive engagement with pistons 31, 32,
33 (236) mounted in cylinders 33 (232) in the cylinder
blocks and wherein a cylinder head 14, 16 (210, 220)
having a suction chamber 56, 58 (298, 302) is located
opposite an outer end of each cylinder block. More-
over, the compressors each have at least one suction
passage 78 or 79 (301 or 301 B, C) extending longi-
tudinally therein between adjacent cylinders in eachcylinder block that directly connects a suction inlet 70
(28~ in the compressor receiving gaseous refrigerant
and entrained oil to both suction chambers while also
exposing one portion of the swash plate sides between
such adjacent cylinders. Furthermore, the gaseous
refrigerant and entrained oil from the suction inlet
flows past the one portion of the swash plate sides
with oil thereby separating and depositing thereon,
and at least some of the gaseous refrigerant and
entrained oil from the suction inlet flows through
a cavity or passage 77 (290) above each journal bearing
defined by the walls 102; 104 (291, 292) of adjacent
cylinders in each cylinder block and in such heat
exchange relation with such walls that some entrained
oil is then separated out by the heat of such walls
and delivered by gravity to the journal bearing and
~ 7 ~3 ~'
36
thrust bearing on the respective swash plate sides
with some of the oil thus separated then flung from
the thrust bearings onto the respeckive swash plate
siaes .
According to the present invention, improved
lubrication as well as weight reduction is accomplished
by the suction chamber 56, 58 1298, 302) of each
cylinder head being loca-ted around the internal peri- -
phery thereof, the ca~ity 77 (290) of each cylinder
block being located adjacent the periphery of the
compressor, the suction inlet 70 (280) being located
in one of the cylinder heads in longitudinal alignmenk
with the cavities 77 (290), the longitudinally
extending suction passage 78 or 79 (301 or 301 B, ~)
being located adjacent the periphery of the compressor
across the compressor and the swash plate sides
remote from the suction inlet, and the cylinder blocks
each having a hollow opening 92, 94 (235) at their
juncture which together form within the compressor
an accommodating space for the swash plate open directly
to the cavities and the longitudinally extending suction
passage, and in addition form a tranversely extending
suction passage extending to the internal periphery
of the compressor and along both sides of the swash
plate and across the axis thereof connecting the suction
inlet to the longitudinally extending suction passage
36
~77~3~
whexeby the weight of the cylinder blocks is substan-
tially reduced and in addition the slidin~ drive
surfaces of both sides of the swash plate are direc-tly
exposed to and completely enveloped by gaseous refriger-
ant and entrained oil as it flows from the suctioninlet to the longitudinally extending suction passage
thereby to ensure that sufficient entrained oil is
caused to separate out as a film on the swash plate
sides. ~oreover, the longitudinally extending suction
passage is defined as a hollow by walls just sufficiently
thick to form adjacent cylinders in each cylindex
block whereby the weight of the cylinder blocks is
substantially further reduced. In addition, the cavities
are defined as a hollow by walls just sufficiently
thick to form adjacent cylinders in each cylinder
block whereby the wei~ht of the cylinder blocks is
subs-tantially further reduced.
As further disclosed in the Figs. 8-23
embodiment, but not a part of the present invention
claimed herein, a dam 362(.F), 362(R) is formed
in-tegral with the two upper cylinder walls 232(A)
and 232(B) in each cylinder block across the respective
valley 360(F), 360(R) at its inboard end so as to
form an oil catch basin 364~F) and 364(R) in the
respective front and rear cylinder block tha-t is
elevated directly above the respective front and
37
7~
38
rear journal bearing 250(F~ and 250(R) when the
compressor is mounted in its normal position or any
position ro~ated in either direction therefrom in
a ran~e o~ + 45 about the compressor centerline. The
oil catch basins 364(F)I 364~R~ are connected to drain
to the respective journal bearinys 250(F), 250~R) by
a vertical passage 366(F), 366(R) respectively,
these oil passages being formed by a vertical radial
groove 368(F), 368(R~ in the outboard f~ce of the
respective cylinder blocks 212, 216 such that the
oil is permitted to drain straight down along the
inboard side of the respective valve disks 223, 227
and into the respective shaf-t accommodating bores 254,
256 and thence directly to the outboard end of the
respective journal bearings 250(F), 250(R).
Thus, oil is caught in the oil catch basins
364(F), 364(R) during compressor opera-tion and is
delivered during continued operation first to the
respective journal bearings 250(F), 250(R) and thence
delivered inboard through the respective bores 254,
256 and along the drive shaft 249 to the thrust bearings
252(F), 252(R) from which such oil is eventually flung
outward therethrough and onto the opposite sides of
the swash plate 241 to lubricate the ball and slipper
drive connections with the pistons 236. Fur-thermore,
the oil catch basins 364(F), 364(1~) also serve to
38
~L~7'7~3~
39
retain a portion of the oil caught therein during
compressor operation for use after each intermittent
stop as normally occurs in the operation o~ the
compressor in vehicle use so that oil is immediately
available to be delivered to the bearings in the
same sequence each time compressor operation is
restarted. Thus, continuous oil wetting of all the
bearings is assured during intermittent compressor
operation.
While the above disclosed embodiments
constitute alternative forms of the present invention,
it will be understood by those skilled in the art
that other forms may be adopted within the scope o
the appended claims.
39
