CA1177037A - Swash plate compressor - Google Patents
Swash plate compressorInfo
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- CA1177037A CA1177037A CA000382092A CA382092A CA1177037A CA 1177037 A CA1177037 A CA 1177037A CA 000382092 A CA000382092 A CA 000382092A CA 382092 A CA382092 A CA 382092A CA 1177037 A CA1177037 A CA 1177037A
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Abstract
D-5,091 SWASH PLATE COMPRESSOR
ABSTRACT of the Disclosure A swash plate compressor of light weigh-t construction having a cylinder block defining weight reducing tubular cylinder bore portions which form, with its outer shell, a low pressure gas upper inlet channel and a pair of low pressure gas lower exit channels. aperture means are provided in one of the heads and its associated valve plate to allow direct axial flow communication from the compressor suction inlet to the upper inlet channel for receiving a mixture of low pressure gas and oil. Aperture means are formed in the compressor heads and their associated valve plates providing communication from the upper inlet channel to the compressor low pressure gas suction chambers via a weight reducing swash plate space that completely exposed the swash plate and each of the lower exit channels. The result is that compressor weight is reduced while lubrication is achieved by the low pressure gas and oil mixture entering the upper inlet channel and flowing in heat exchange relation with the upper tubular portions separating a portion of the oil from gas for deposit on the upper tubular portions for subsequent gravita-tional flow to the operation portions of the compressor and with the low pressure gas and oil mixture directly exposed to and enveloping the swash plate to ensure that sufficient entrained oil is caused to separate out as a film on the swash plate sides.
ABSTRACT of the Disclosure A swash plate compressor of light weigh-t construction having a cylinder block defining weight reducing tubular cylinder bore portions which form, with its outer shell, a low pressure gas upper inlet channel and a pair of low pressure gas lower exit channels. aperture means are provided in one of the heads and its associated valve plate to allow direct axial flow communication from the compressor suction inlet to the upper inlet channel for receiving a mixture of low pressure gas and oil. Aperture means are formed in the compressor heads and their associated valve plates providing communication from the upper inlet channel to the compressor low pressure gas suction chambers via a weight reducing swash plate space that completely exposed the swash plate and each of the lower exit channels. The result is that compressor weight is reduced while lubrication is achieved by the low pressure gas and oil mixture entering the upper inlet channel and flowing in heat exchange relation with the upper tubular portions separating a portion of the oil from gas for deposit on the upper tubular portions for subsequent gravita-tional flow to the operation portions of the compressor and with the low pressure gas and oil mixture directly exposed to and enveloping the swash plate to ensure that sufficient entrained oil is caused to separate out as a film on the swash plate sides.
Description
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;
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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~
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 ~ ~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.
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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 P3~
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 ~ ~.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 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~
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 ~7t7~3~
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 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 ~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 !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 ~'7~ 3~
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.
~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 ~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 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 ~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 3 ~
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 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 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 ~ 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.
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 ~7~7~3~
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) ~.~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 ~' 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 ~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 7~
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 ~L~7'7~3~
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.
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~
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 ~ ~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.
~7'7~
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 P3~
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 ~ ~.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 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~
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 ~7t7~3~
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 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 ~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 !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 ~'7~ 3~
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.
~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 ~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 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 ~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 3 ~
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 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 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 ~ 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.
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 ~7~7~3~
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) ~.~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 ~' 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 ~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 7~
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 ~L~7'7~3~
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.
Claims (3)
1. In an axial-piston swash plate refrigerant compressor of the type having a swash plate that is rotatably supported and axially contained between a pair of end-to-end joined cylinder blocks by a journal bearing and a thrust bearing on opposite sides of the swash plate and wherein the swash plate sides are in sliding drive engagement with pistons mounted in cyl-inders in the cylinder blocks and wherein a cylinder head having a suction chamber is located opposite an outer end of each cylinder block and wherein at least one suction passage extends longitudinally within the compressor between adjacent cylinders in each cylinder block and directly connects a suction inlet 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, and wherein 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 wherein at least some of the gaseous refrigerant and entrained oil from the suction inlet flows through a cavity or passage above each journal bearing defined by the walls of adjacent cylinders in each cylinder block and in such heat exchange relation with such walls that some en-trained oil is then separated out by the heat of such walls and delivered by gravity to the journal bearing and thrust bearing on the respective swash plate sides with some of the oil thus separated then flung from the thrust bearings onto the respective swash plate sides, characterized in that the suction chamber of each cylinder head is located around the internal periphery thereof, the cavity of each cylinder block is located adjacent the periphery of the compressor, the suction inlet is located in one of the cylinder heads in longi-tudinal alignment with said cavities, the longitudinally extending suction passage is 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 have a hollow opening 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 transversely 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 whereby the weight of the cylinder blocks is substantially reduced and in addition the sliding drive surfaces of both sides of the swash plate are directly exposed to and completely enveloped by gaseous refrigerant and entrained oil as it flows from the suction inlet 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.
to ensure that sufficient entrained oil is caused to separate out as a film on the swash plate sides.
2. An axial-piston swash plate compressor according to claim 1, characterized in that the longi-tudinally extending suction passage is defined as a hollow by walls just sufficiently thick to form adja-cent cylinders in each cylinder block whereby the weight of the cylinder blocks is substantially further reduced.
3. An axial-piston swash plate compressor according to claim 1 or 2, characterized in that the cavities are defined as a hollow by walls just suffi-ciently thick to form adjacent cylinders in each cylinder block whereby the weight of the cylinder blocks is substantially further reduced.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/186,749 US4347046A (en) | 1978-12-04 | 1980-09-12 | Swash plate compressor |
| US186,749 | 1980-09-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1177037A true CA1177037A (en) | 1984-10-30 |
Family
ID=22686147
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000382092A Expired CA1177037A (en) | 1980-09-12 | 1981-07-20 | Swash plate compressor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1177037A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107956675A (en) * | 2018-01-11 | 2018-04-24 | 无锡立欣空调科技有限公司 | The rear cover and intelligent electric-controlled compressor of a kind of intelligent electric-controlled compressor |
-
1981
- 1981-07-20 CA CA000382092A patent/CA1177037A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107956675A (en) * | 2018-01-11 | 2018-04-24 | 无锡立欣空调科技有限公司 | The rear cover and intelligent electric-controlled compressor of a kind of intelligent electric-controlled compressor |
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