USRE40554E1 - Capacity modulated scroll machine having one or more pin members movably disposed for restricting the radius of the orbiting scroll member - Google Patents

Abstract

A scroll-type machine is disclosed which is particularly well suited for use as a compressor in refrigeration and air conditioning systems and incorporates a unique arrangement for modulating the capacity thereof. In one group of embodiments the capacity of the scroll-type machine is modulated by relative axial movement between the scroll members so as to form a leakage path across the wrap tips and opposed end plates. In another group of embodiments, modulation is achieved by reducing the orbital radius of one of the scroll members to thereby form a leakage path across the flank surfaces of the wraps. In the second group, a plurality of pin members are moveable from a first and second positions. In a first position the plurality of pin members operably enable the scroll members to orbit and in a second position the pin members restrict the orbiting motion of the first scroll members. Both types of scroll separation may be accomplished in a time pulsed manner to thereby enable a full range of modulation with the duration of the loading and unloading periods being selected to maximize the efficiency of the overall system. A motor control arrangement is also disclosed which may be used with either of the modulation methods mentioned above to increase the efficiency of the motor during periods of reduced load. Additionally, either of the modulation arrangements mentioned above may be combined with a delayed suction form of capacity modulation with or without the motor control feature to thereby achieve better operating efficiency under certain conditions.

Description

This is a division of U.S. patent application Ser. No. 08/486,118, filed Jun. 7, 1995 U.S. Pat. No. 5,741,120.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention is related to capacity modulation of compressors and more particularly to capacity modulation of scroll-type compressors.

Capacity modulation is often a desirable feature to incorporate in air conditioning and refrigeration compressors in order to better accommodate the wide range of loading to which the systems may be subjected. Many different approaches have been utilized for providing this capacity modulation feature ranging from controlling of the suction inlet to bypassing discharge gas back to the suction inlet. With scroll-type compressors, capacity modulation has often been accomplished via a delayed suction approach which comprises providing ports at various positions which, when opened, allow the compression chambers formed between the intermeshing scroll wraps to communicate with the suction gas supply thereby delaying the point at which compression of the suction gas begins. This method of capacity modulation actually reduces the compression ratio of the compressor. While such systems are effective at reducing the capacity of the compressor, they are only able to provide a predetermined amount of compressor unloading, the amount of unloading being dependent upon the positioning of the unloading ports along the wraps. While it is possible to provide multiple step unloading by incorporating a plurality of such ports at different locations, this approach becomes costly and requires additional space to accommodate the separate controls for opening and closing each set of ports.

The present invention, however, overcomes these deficiencies in that it enables virtually a continuous range of unloading from 100 percent or full capacity down to virtually zero capacity utilizing only a single set of controls. Further, the system of the present invention enables the operating efficiency of the compressor and/or refrigeration system to be maximized for any degree of compressor unloading desired.

In the present invention, compressor unloading is accomplished by cyclically effecting axial or radial separation of the two scroll members for predetermined periods of time during the operating cycle of the compressor. More specifically, the present invention provides an arrangement wherein one scroll member is moved axially or radially toward and away from the other scroll member in a pulsed fashion to cyclically provide a leakage path across the tips or flanks of the wraps from higher pressure compression pockets defined by the intermeshing scroll wraps to lower pressure pockets and ultimately back to suction. By controlling the relative time between sealing and unsealing of the scroll wrap tips or flanks, virtually any degree of compressor unloading can be achieved with a single control system. Further, by sensing various conditions within the refrigeration system, the duration of compressor loading and unloading for each cycle can be selected for a given capacity such that overall system efficiency is maximized. For example, if it is desired to operate the compressor at 50 percent capacity, this can be accomplished by operating the compressor alternately in a loaded condition for five seconds and unloaded for five seconds or loaded for seven seconds and unloaded for seven seconds, one or the other of which may provide greater efficiency for the specific operating conditions being encountered.

The various embodiments of the present invention described below provide a wide variety of arrangements by which one scroll member may be axially or radially reciprocated with respect to the other to accommodate a full range of compressor unloading. The ability to provide a full range of capacity modulation with a single control system as well as the ability to select the duration of loaded and unloaded operation cooperate to provide an extremely efficient system at a relatively low cost.

Additionally, in order to even further improve system efficiency in some applications, it may be desirable to combine a delayed suction type of capacity modulation with the pulsed unloading approach mentioned above. For example, when operating conditions are such that system pressures just downstream of the discharge valve are at a level below the full load design level, the compression ratio of the compressor will result in pressure of the compressed fluid as it is discharged from the compression chamber being too high, a condition known as over-compression. The most efficient way to reduce capacity under these conditions is to reduce the compression ratio of the compressor and hence the pressure of the compressed fluid exiting the compression chamber such that it is equal to or only slightly above the system pressure just downstream of the discharge valve thus eliminating the lost work due to over-compression. However, if a further reduction in capacity is indicated by system condition once the over-compression condition has been eliminated, the use of a pulsed type of capacity modulation will be more efficient as it will avoid creation of a condition known as under-compression, that being a situation where the pressure of the compressed fluid as it leaves the compression chamber being below that of the system just downstream of the discharge valve. Thus, the present invention also includes a system in which both pulsed and delayed suction capacity modulation approaches are combined which result in even greater efficiencies for systems likely to encounter such operating conditions than could be achieved by either of the two capacity modulation approaches alone.

Additionally, the present invention may also incorporate a motor control module which will operate to control various operating parameters thereof to enhance its operating efficiency during periods when the motor load is reduced due to unloading of the compressor.

Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view of a scroll-type refrigeration compressor in accordance with the present invention;

FIG. 2 is a fragmentary section view of a scroll-type refrigeration compressor showing another embodiment of the present invention;

FIG. 3 is a view similar to that ofFIG. 2 but showing the compressor in an unloaded condition;

FIG. 4 is a fragmentary section view of a scroll-type refrigeration compressor showing a further embodiment of the present invention;

FIG. 5 is an enlarged view of the valve arrangement incorporated in the embodiment shown inFIG. 4;

FIG. 6 is also a fragmentary section view of a scroll-type refrigeration compressor showing another embodiment of the present invention;

FIGS. 7 through 15 are all fragmentary section views of refrigeration compressors in accordance with the present invention in which the orbiting scroll member is axially reciprocated to accomplish compressor unloading;

FIGS. 16 through 22 are all fragmentary section views of refrigeration compressors in accordance with the present invention in which the non-orbiting scroll member is axially reciprocated to accomplish compressor unloading;

FIGS. 23 through 28 are all fragmentary section views of refrigeration compressors in accordance with the present invention in which the scroll members are co-rotating;

FIGS. 29 through 30 are both fragmentary section views of additional embodiments of refrigeration compressors all in accordance with the present invention in which the non-orbiting scroll member is reciprocated; and

FIG. 31 is a section view of yet another embodiment of a scroll-type compressor in accordance with the present invention adapted to be driven by an external power source;

FIGS. 32 through 34 are fragmentary section views of additional embodiments of scroll-type compressors in accordance with the present invention;

FIG. 34A is an enlarged fragmentary view of the valving arrangement shown in FIG.34 and enclosed withincircle34A;

FIG. 35 is a fragmentary section view of a further embodiment of a scroll-type compressor in accordance with the present invention;

FIG. 36 is also a fragmentary section view of yet a further embodiment of the present invention showing an arrangement for radially unloading of the compressor in accordance with the present invention;

FIG. 37 is a section view of the crank pin and drive bushing employed in the embodiment ofFIG. 36, the section being taken alonglines37—37 thereof;

FIG. 38 is a section view of the embodiment shown inFIG. 36, the section being taken alonglines38—38 thereof;

FIG. 39 is a view similar to that ofFIG. 36 but showing the compressor in an unloaded condition;

FIG. 40 is a fragmentary section view showing a modified version of the embodiment ofFIG. 36, all in accordance with the present invention;

FIG. 41 is a fragmentary section view showing a portion of a scroll-type compressor incorporating another embodiment of the radial unloading arrangement ofFIG. 36, all in accordance with the present invention;

FIG. 42 is a section view similar to that ofFIG. 38 but showing the embodiment ofFIG. 41;

FIG. 43 is a fragmentary section view showing yet another embodiment of the present invention;

FIG. 44 is a view of a portion of the embodiment shown inFIG. 43 in an unloaded condition;

FIG. 45 is a schematic showing a means for reducing motor power consumption during periods when the compressor is operating in an unloaded condition in accordance with the present invention; and

FIG. 46 is a section view of a compressor incorporating both cyclical scroll wrap separation and delayed suction unloading, all in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and in particular toFIG. 1, there is shown a hermetic scroll compressor in accordance with the present invention indicated generally at10.Scroll compressor10 is generally of the type described in assignee's U.S. Pat. No. 5,102,316, the disclosure of which is incorporated by reference, and includes anouter shell12 within which is disposed a drivingmotor including stator14 androtor16, acrankshaft18 to whichrotor16 is secured, upper and lower bearinghousings20,22 for rotatably supportingcrankshaft18 andcompressor assembly24.

Compressor assembly24 includes an orbitingscroll member26 supported on upper bearinghousing20 and drivingly connected tocrankshaft18 viacrank pin28 and drive bushing30. A secondnon-orbiting scroll member32 is positioned in meshing engagement withscroll member26 and axially movably secured to upper bearinghousing20 by means of a plurality ofbolts34 and associatedsleeve members36. An Oldhamcoupling38 is provided which cooperates betweenscroll members26 and32 to prevent relative rotation therebetween.

Apartition plate40 is provided adjacent the upper end ofshell12 and serves to define adischarge chamber42 at the upper end thereof.

In operation, as orbitingscroll member26 orbits with respect toscroll member32, suction gas is drawn intoshell12 viasuction inlet44 and thence intocompressor24 throughinlet46 provided innon-orbiting scroll member32. The intermeshing wraps provided onscroll members26 and32 define moving fluid pockets which progressively decrease in size and move radially inwardly as a result of the orbiting motion ofscroll member26 thus compressing the suction gas entering viainlet46. The compressed gas is then discharged intodischarge chamber42 viadischarge port48 provided inscroll member32 andpassage50. A suitable pressureresponsive discharge valve51 is preferably provided seated withindischarge port48.

Scrollmember32 is also provided with an annularcylindrical recess52 formed in the upper surface thereof. One end of a generally irregularly shapedcylindrical member54 within whichpassage50 is provided projects intocylinder52 and divides same into upper andlower chambers56 and58. The other end ofcylindrical member54 is sealingly secured topartition plate40. Anannular ring60 is secured to the upper end ofscroll member32 and includes anaxially extending flange62 slidingly engageable withcylinder member54 to thereby seal off the open upper end ofchamber56.

Cylindrical member54 includes apassage64 having one end which opens intoupper chamber56. Afluid line66 is connected to the other end ofpassage64 and extends outwardly throughshell12 to a solenoid operatedvalve68. Asecond fluid line70 extends fromvalve68 tosuction line72 connected tosuction inlet44 and athird fluid line74 extends fromvalve68 to adischarge line76 extending outwardly fromdischarge chamber42.

In order to biasscroll member32 into sealing engagement withscroll member26 for normal fully loaded operation, ableed hole78 is provided inscroll member32 communicating betweenchamber58 and a compression pocket at an intermediate pressure between suction and discharge pressure. Thus,chamber58 will be at an intermediate pressure which together with the discharge pressure acting on the upper surface ofscroll member32 in the area ofdischarge port48 will exert a biasing force on scroll member urging it axially into sealing engagement with orbitingscroll member26. At the same time,solenoid valve68 will be in a position so as to placeupper chamber56 in fluid communication withsuction line72 viafluid lines66 and70.

In order to unloadcompressor24,solenoid valve68 will be actuated in response to a signal fromcontrol module80 to interrupt fluid communication betweenlines66 and70 and to placefluid line66 in communication withdischarge line76 thus increasing the pressure withinchamber56 to that of the discharge gas. The biasing force resulting from this discharge pressure will overcome the sealing biasing force thereby causingscroll member32 to move axially upwardly away from orbitingscroll member26. This axial movement will result in the creation of a leakage path between the respective wrap tips and end plates ofscroll members26 and32 thereby substantially eliminating continued compression of the suction gas. When unloading occurs,discharge valve51 will move to a closed position thereby preventing the back flow of high pressure fluid fromdischarge chamber42 or the downstream system. When compression of the suction gas is to be resumed,solenoid valve68 will be actuated to a position in which fluid communication betweenupper chamber56 anddischarge line76 vialines66 and74 is interrupted andupper chamber56 is placed in communication withsuction line72 viafluid lines66 and70 thereby relieving the axially directed separating force. This then allows the cooperative action of the intermediate pressure inchamber58 and discharge pressure acting inpassage50 to again movescroll member32 into sealing engagement withscroll member26.

Preferably,control module80 will have one or moreappropriate sensors82 connected thereto to provide the required information forcontrol module80 to determine the degree of unloading required for the particular conditions existing at that time. Based upon this information,control module80 will send appropriately timed sequential signals tosolenoid valve68 to cause it to alternately placefluid line66 in communication withdischarge line76 andsuction line72. For example, if conditions indicate that it is desirable to operatecompressor24 at 50 percent of full capacity,control module80 may actuate solenoid valve to a position to placefluid line66 in communication withsuction line72 for a period of say 10 seconds whereupon it is switched to placefluid line66 in fluid communication withdischarge line76 for a like period of 10 seconds. Continued switching ofsolenoid valve68 in this manner will result in compression occurring during only 50 percent of the operating time thus reducing the output ofcompressor24 to 50 percent of its full load capacity. As the sensed conditions change, control module will vary the relative time periods at whichcompressor24 is operated in a loaded and unloaded condition such that the capacity ofcompressor24 may be varied between fully loaded or 100 percent capacity and completely unloaded or 0 percent capacity in response to varying system demands.

FIGS. 2 and 3 show an axialunloading scroll compressor34 similar to that ofFIG. 1 with the primary exception being the arrangement for placingupper chamber56 in fluid communication with suction and discharge lines. Accordingly, like portions have been indicated by the same reference numbers. As shown therein,passage64 has been replaced by apassage86 provided inannular member60 which opens at one end intoupper chamber56 and at the other end through a radially outwardly facing sidewall. Aflexible fluid line88 extends from the outer end ofpassage86 to a fitting90 extending throughshell12 with asecond line92 connecting fitting90 tosolenoid valve68. As withFIG. 1,solenoid valve68 hasfluid lines70 and74 connected tosuction line72 anddischarge line76 and is controlled bycontrol module80 in response to conditions sensed bysensor82 to effect movement ofnon-orbiting scroll member32 between the positions shown inFIGS. 2 and 3 in the same manner as described above with respect to the embodiment of FIG.1. While this embodiment eliminates the need for an extra fitting extending outwardly from the highpressure discharge chamber42, it requires thatfluid conduit88 be flexible so as to accommodate axial movement ofscroll member32 and associatedannular member60. It should also be noted that in this embodimentcylindrical member54 is sealing secured topartition plate40 by means ofnut55 which threadedly engages the upper end thereof. Also in this embodiment,discharge valve51 has been replaced by adischarge check valve93 secured to the outer shell. It should be noted that the provision of a check valve some place along the discharge flowpath is highly desirable in order to prevent back flow of compressed gas from the system when the compressor is in an unloaded condition.

FIGS. 4 and 5 show anotherembodiment94 of the present invention in which axial unloading separating pressure fluid is provided directly from the discharge gas exiting the compressor. In this embodiment, atubular member96 is suitably secured topartition member40 and includes a radially outwardly extendingflange98 which is positioned in and separates cylindrical recess into upper andlower chambers56 and58.Tubular member96 also definespassage50 for directing compressed discharge gas fromport48 to dischargechamber42. An axial extendingbore100 is provided in tubular member which opens outwardly through the upper end thereof and is adapted to receive afluid conduit102.Fluid conduit102 extends outwardly through the top ofshell12 and is connected to solenoidvalve68. Solenoid valve also hasfluid conduits70 and74 connected to respective suction anddischarge lines72,76 and is controlled bycontrol module80 in response to signals fromappropriate sensors82 in the same manner as described above.

Avalve member104 is axially movably disposed withinbore100.Valve member104 includes a reduceddiameter portion106 operative to place radially extendingpassages108 and110 provided inmember96 in fluid communication when in a first position so as to ventupper chamber56 to suction and to placeradial fluid passage110 in fluid communication withradial fluid passage112 when in a second position so as to admit discharge gas from discharge flow-path50 toupper chamber56. Avent passage113 is also provided with communicates between the bottom ofbore100 andpassage50 to vent gas from the area belowvalve104 during operation thereof. Aspring114 is also provided which serves to aid in biasingvalve104 into its second position whereas pressurized discharge fluid entering bore100 viapassage112 andpassage113 serves to biasvalve member104 into its first position.

As shown,valve member104 andsolenoid valve68 are both in a position for fully loaded operation whereinsolenoid valve68 is in position to placefluid conduit102 in communication with thesuction line72 andvalve member104 is in a position to ventupper chamber56 to the interior ofshell12 which is at suction pressure. When it is desired to unload the compressor,solenoid valve68 will be actuated to a position to placefluid line102 in communication withfluid line74 thereby enabling pressurized discharge fluid to act on the upper end ofvalve member104. This pressurized fluid together withspring114 will causevalve member104 to move downwardly thereby closing off communication ofradial passage110 withradial passage108 and opening communication betweenradial passage110 andradial passage112. Discharge pressure fluid will then flow intoupper chamber56 thus overcoming the intermediate pressure biasing force resulting from the communication ofchamber58 with a compression chamber at intermediate pressure viapassage78 and causingscroll member32 to move axially upwardly away from orbitingscroll member26. It should be noted that the relatively short flowpath for supplying discharge pressure fluid toupper chamber56 ensures rapid unloading of the compressor.

FIG. 6 shows a modified embodiment similar to that ofFIGS. 4 and 5 except thatsolenoid valve68 is positioned withinshell12. This embodiment eliminates the need for an additional fluid conduit through the high pressure portion of the shell, requiring only an electrical feed for actuatingsolenoid valve68. In all other respects, construction and operation of this embodiment is substantially the same as that described above with respect to the embodiment shown inFIGS. 4 and 5 and accordingly corresponding portions are indicated by the same reference numbers.

While the previously described embodiments have been directed to unloading arrangements wherein the non-orbiting scroll has been moved axially away from the orbiting scroll, it is also possible to apply these same principles to the orbiting scroll.FIGS. 7 through 15 described below illustrate such a series of embodiments.

Referring now toFIG. 7, ascroll compressor140 is shown which is similar to the scroll compressors described above except thatnon-orbiting scroll member142 is non-movably secured to bearinghousing144 and orbitingscroll member146 is axially movable. It is also noted thatcompressor140 is a high side machine, that is, thesuction inlet149 is directly connected to thenon-orbiting scroll member142 and the interior of theshell12 is at discharge pressure. In this embodiment, orbitingscroll member146 is axially movable and is biased into engagement withnon-orbiting scroll142 by means of apressure chamber148 defined between orbitingscroll member146 andmain bearing housing144. Anannular recess150 is provided inmain bearing housing144 in which is disposed a suitable annularresilient seal member152 which sealingly engages the lower surface of orbitingscroll member146 so as to prevent fluid communication betweenchamber148 and the interior ofshell12 which is at discharge pressure. A secondannular seal154 is provided onmain bearing housing144 surroundingshaft18 to prevent fluid leakage therealong. Asmall passage156 is provided through the end plate of orbitingscroll member146 to placechamber148 in fluid communication with a compression chamber at a pressure intermediate suction and discharge pressure. Additionally, apassage158 in main bearing housing extends outwardly fromchamber148 and has one end offluid line160 connected thereto. The other end offluid line160 extends outwardly throughshell12 and is connected tosolenoid valve162. Asecond fluid line164 extendssolenoid valve162 andsuction line148.

In operation,chamber148 will be supplied with fluid at intermediate pressure to thereby biasingorbiting scroll146 into sealing engagement withnon-orbiting scroll142. At this time,solenoid valve162 will be in a position to prevent fluid communication betweenlines160 and164. In order to unloadcompressor140,solenoid valve162 is actuated to a position to placeline160 in fluid communication withfluid line164 thereby venting the intermediate pressure inchamber148 to suction. The pressure within the compression pockets will then cause orbitingscroll member146 to move axially downwardly as shown compressingresilient seals152 and thereby forming a leakage path across the respective wrap tips and associated end plates of the orbiting andnon-orbiting scroll members146,142. Whilepassage156 may continue to provide fluid at a pressure somewhat higher than suction pressure tochamber148, the relative sizing ofpassage158,fluid lines160 and164 andpassage158 will be such that there will be insufficient pressure inchamber148 to bias orbitingscroll member146 into sealing engagement withnon-orbiting scroll member142 so long assolenoid valve162 is in a position to maintain fluid communication betweensuction line149 andchamber148.Solenoid valve162 will be cycled between open and closed positions so as to cyclically load and unloadcompressor140 in substantially the same manner as described above.

FIG. 8 shows a modifiedversion140a of the embodiment ofFIG. 7 wherein a plurality ofsprings166 are provided.Springs166 are seated inrecesses168 provided in bearinghousing144a and bear against the end plate of orbitingscroll146 so as to assist in urging orbiting scroll into sealing engagement withnon-orbiting scroll142.Springs166 serve primarily to provide an initial biasing force for orbitingscroll member146 on initial start up ofcompressor140a but will also assist in providing more rapid loading ofcompressor140a upon closing ofsolenoid valve162 during operation.

FIG. 9 shows afurther modification140b of the embodiments ofFIGS. 7 and 8. In thisembodiment shell12 is provided with apartition member170 to separate the interior thereof into a highpressure discharge chamber172 to whichdischarge port174 is connected viaconduit176 and a low suction pressure chamber therebelow within which the compressor is disposed. Additionally, in thisembodiment shaft seal154 has been replaced with a secondannular seal178 positioned radially inwardly and concentric withseal150b. Thus the area in which crankpin28 and drivebushing30 are located will be at suction pressure to thereby avoid any problems associated with providing lubrication thereto from the oil sump which is also at suction pressure. It should be noted that the oil sump in the embodiments ofFIGS. 7 and 8 was at discharge pressure and hence do not present any problems with respect to supplying of lubricant to these drive components.

Theembodiment140c ofFIG. 10 is substantially identical to that ofFIG. 9 with the exception that in addition to the biasing force resulting from intermediate fluid pressure inchamber148b, a plurality ofsprings180 are also provided being positioned between orbitingscroll member156 andmain bearing housing144 and functioning primarily to assist during start up but also to assist in reloading ofcompressor140c similar to that described above with reference to FIG.8.

In the embodiment ofFIG. 11,non-orbiting scroll member182 is provided with anannular recess184 within which an annular ring-shapedpiston member186 is movably disposed. The lower surface ofannular piston member186 bears against a radially outwardly extendingportion187 ofend plate189 of orbitingscroll member146 and radially inner and outerannular seals188,190 are provided thereon which sealingly engage radially inner and outer walls ofrecess184. Aradially extending passage192 provided innon-orbiting scroll member182 communicates with the upper portion ofrecess184 and hasfluid conduit194 connected to the outer end thereof.Fluid conduit194 extends outwardly throughshell12 tosolenoid valve196. A secondfluid conduit198 connectssolenoid valve196 tosuction line200 whereas a thirdfluid conduit202 connectssolenoid valve196 to dischargeline204.

Under normal fully loaded operating conditions, orbitingscroll member146 will be axially biased into sealing engagement withnon-orbiting scroll member182 by intermediate fluid pressure inchamber206 admitted thereto viableed passage208. At this time, the area ofrecess184 disposed aboveannular piston member186 will be vented to suction viasolenoid valve196 andconduits194 and198. When conditions indicate partial unloading of the compressor is desirable,solenoid valve196 will be actuated to placefluid conduit194 in fluid communication withdischarge line204 viaconduit202. The area aboveannular piston186 will then be pressurized by fluid at discharge pressure thereby causing orbitingscroll member146 to be biased axially downwardly as shown. As noted above, cyclical switching ofsolenoid valve196 will result in repetitive loading and unloading of the compressor with the degree of unloading being determined by associated sensors and control module (not shown). It should be noted that in this embodiment, the compressor is shown as a high side machine and thussuction inlet200 is directly connected to the suction inlet ofnon-orbiting scroll182.

Theembodiment208 ofFIG. 12 represents a combination of the axial unloading arrangement of FIG.11 and the orbiting scroll biasing arrangement ofFIG. 9 both described above. Accordingly, elements corresponding to like elements shown in and described with reference toFIGS. 9 and 11 are indicated by the same reference numbers. In this embodiment, the intermediate pressureaxial biasing chamber148b for the orbiting scroll is completely separate from the unloading discharge pressure biasing chamber defined byrecess184 andannular piston186.

In like manner, theembodiment210 ofFIG. 13 represents a combination of the intermediate pressure biasing arrangement ofFIG. 8 described above and the axial unloading pressure biasing arrangement of FIG.11. Accordingly, corresponding elements have been indicated by the same reference numbers used in these respective figures.

FIG. 14 shows anembodiment212 whereinshell12 includes anupper chamber214 at discharge pressure and alower portion216 at a pressure intermediate suction and discharge. Accordingly,suction line234 is directly connected tonon-orbiting scroll member224. Additionally, a suitableannular seal225 may be provided betweenorbiting scroll222 andnon-orbiting scroll224 around the outer periphery thereof. Orbitingscroll222 is biased into sealing relationship withnon-orbiting scroll224 by intermediate pressure inchamber216 supplied viapassage226. In order to unloadcompressor212, asolenoid valve228 is provided having afirst fluid line230 extending throughshell12 and being connected to one end of apassage231 provided inlower bearing housing233. Asecond fluid line232 is connected between thesuction inlet234 andsolenoid valve228. Whensolenoid valve228 is opened, the intermediate pressure acting on the lower surface of orbitingscroll222 will be vented to suction viapassage231,fluid line230,solenoid valve228 andfluid line232. Becausepassage231,fluid lines230 and232 andsolenoid valve228 will be sized to provide a flow volume greater than that throughpassage226 plus the leakage into the area defined between the bearing housing and end plate of orbitingscroll222, the biasing force acting on orbitingscroll222 will be relieved thus allowing the force of the fluid within the compression chamber to move orbitingscroll222 axially away fromnon-orbiting scroll224. As soon assolenoid valve228 is closed, leakage flow of intermediate pressure fluid withinlower portion216 ofshell12 combined with flow frompassage226 will quickly restore the biasing force on orbitingscroll222 whereby full compression will resume. Again, as with each of the above embodiments, cyclical actuation ofsolenoid valve228 in response to a signal from a control module (not shown) resulting from appropriate sensed system conditions will result in cyclical loading and unloading of compressor thereby enabling modulation of capacity from 100 percent down to 0 percent capacity.

FIG. 15 shows anembodiment236 which combines the features of an intermediate pressure lower shell and biasing arrangement for the orbiting scroll as shown inFIG. 14 with the discharge pressure unloading arrangement of FIG.11. Accordingly, corresponding portions thereof are indicated by the same reference numbers. Additionally, as described with reference toFIGS. 8,10, and13, a plurality ofsprings238 are provided being positioned inrecess240 provided inmain bearing housing242 and acting on the lower surface of the end plate of orbitingscroll member222. As noted above, springs238 serve primarily to bias orbitingscroll member222 into sealing engagement withnon-orbiting scroll member182 during initial start up and also aid in reloading ofcompressor236. Again, full and reduced loading ofcompressor236 will be accomplished in the same manner as described above by means of cyclic actuation ofsolenoid valve196.

Referring now toFIG. 16, yet anotherembodiment244 of the present invention is shown which is generally similar to that of FIG.1 and includes ashell12 having a separatingplate246 dividing the interior thereof into adischarge chamber248 and alower chamber250 at suction pressure. Acylindrical member252 is secured to plate246 and defines aflow path254 for conducting compressed fluid fromdischarge port256 of axially movablenon-orbiting scroll258.Non-orbiting scroll258 has an annular recess provided in the upper surface thereof which is separated into upper andlower chambers260,262 respectively by a radially outwardly extendingannular flange264 provided oncylindrical member252. Apassage266 placeslower chamber262 in fluid communication with a compression pocket at intermediate pressure to provide a biasing force for urgingnon-orbiting scroll258 into sealing engagement with orbitingscroll268. Anannular plate member269 is secured tonon-orbiting scroll258, sealingly and slidingly engagestubular member252 and serves to close off the top ofchamber260. A pressure responsivedischarge check valve270 is also provided onnon-orbiting scroll258.

A twoway solenoid valve270 is provided being connected to dischargeconduit272 viafluid line274 and toupper separating chamber260 viafluid line276 andpassage278 intubular member252. Avent passage280 is provided betweennon-orbiting scroll258 andplate269 and extends between separatingchamber260 and thelower interior250 ofshell12 which is at suction pressure.Vent passage280 serves to continuously vent separatingchamber260 to suction pressure. Whensolenoid valve270 is in a closed position,compressor244 will be fully loaded as shown. However, whensolenoid valve270 is actuated to an open position by the control module (not shown) in response to selected sensed conditions, separatingchamber260 will become pressurized to substantially discharge pressure thereby overcoming the combined force of discharge pressure and suction pressure acting to biasnon-orbiting scroll member258 toward orbitingscroll member268. Thus,non-orbiting scroll member258 will move axially upwardly as shown thereby unloadingcompressor244. It should be noted that in this embodiment, the size oflines274 and276 andpassage278 must be selected relative to the size ofvent passage280 to enable build up of sufficient pressure in separatingchamber260 to effect unloading. Additionally, the relative size of these passages will affect the speed at whichcompressor244 may be cycled between loaded and unloaded conditions as well as the volume of discharge gas required to accomplish and maintain unloading.

The embodiment ofFIG. 17 is generally similar to that ofFIG. 16 described above except thatspring biasing members282 are included in the intermediate pressure chamber. Accordingly, corresponding elements are indicated by the same reference numbers primed. As noted above, springs280 serve primarily to assist in biasingnon-orbiting scroll member258 into sealing relationship with orbitingscroll member268 during start up but will also function to assist in reloadingcompressor244. In all other respects, the operation ofcompressor244 will be substantially identical to that described with reference toFIGS. 1 and 16 above.

Referring now toFIG. 18, a further embodiment of the present invention is shown being indicated generally at284.Compressor284 includes anouter shell12 having a separatingplate286 dividing the interior thereof into adischarge chamber290 and alower chamber292 at suction pressure. Acylindrical member294 is suitably secured to plate286 and slidingly sealingly engages a cylindrical portion of axially movablenon-orbiting scroll member296 so as to define a dischargefluid flow path298 fromdischarge port300. A pressure responsivedischarge check valve302 is also provided being secured tonon-orbiting scroll296 and operative to prevent back flow of discharge fluid fromchamber290 into the compression chambers.Non-orbiting scroll296 includes a pair of annular steppedportions304,306 on its outer periphery which cooperate withcomplementary portions308,310 onmain bearing housing312 to define a generallyannular separating chamber314. Additionally,non-orbiting scroll296 includes a radially outwardly projectingflange portion316 which cooperates with a radially inwardly projectingflange portion318 onmain bearing housing312 to limit axially separating movement onnon-orbiting scroll296.

Asolenoid valve320 is also provided being connected in fluid communication withchamber314 viapassage322 inmain bearing housing312 andfluid line324.Fluid lines326 and328 serve to interconnectsolenoid valve320 withdischarge line330 andsuction line332 respectively.

Similarly to that described above, whencompressor284 is operating under a normal fully loaded condition as shown,solenoid valve320 will be in a position to placechamber314 in fluid communication withsuction line332 viapassageway322 andfluid lines324 and328. Under these conditions, the biasing force resulting from discharge pressure fluid inchamber290 acting on the upper surface ofnon-orbiting scroll296 withinflow path298 will operate to urgenon-orbiting scroll296 into sealing engagement with orbitingscroll334. When it is desired to unloadcompressor284,solenoid valve320 will operate to placechamber314 in fluid communication with discharge pressure fluid viafluid lines326,324 andpassageway322. The resulting pressure inchamber314 will then operate to overcome the biasing force being exerted onnon-orbiting scroll296 thus causing it to move axially upwardly as shown and out of sealing engagement with orbitingscroll334 thus unloadingcompressor284. To reloadcompressor296,solenoid valve320 will operate to vent the discharge pressure fluid inchamber314 tosuction line332 viapassage322 andfluid lines324,328 thereby allowing the biasing force acting onnon-orbiting scroll296 to move it axially downwardly back into sealing engagement with orbitingscroll334. In like manner, as noted above, operation ofsolenoid valve320 will be controlled by a suitable control module (not shown) in response to system conditions sensed by one or more sensors to cyclically load and unloadcompressor284 as needed.

A further embodiment of the present invention is shown inFIG. 19 being indicated generally at336 which is similar to the embodiment shown in FIG.18. Accordingly, corresponding portions thereof have been indicated by the same reference numbers primed. In this embodiment,lower portion292′ ofshell12′ is at intermediate pressure supplied viapassage338 in orbitingscroll334′ which also acts to exert an upwardly directed biasing force thereon. Additionally,ring member340 which includes steppedportions308′,310′ is separately fabricated and secured tomain bearing housing342.Ring member340 also includes aportion344 which extends into overlying relationship with the end plate of orbitingscroll member334′ and operates to limit upward movement thereof whencompressor336 is in an unloaded condition. Additionally, an internalflexible suction line346 is provided being connected tosuction line332′ and tonon-orbiting scroll296′. Acheck valve348 is provided at the connection ofline346 withnon-orbiting scroll296′ and serves to prevent back flow of fluid under compression whencompressor336 is unloaded. Asuction control device350 is also optionally provided insuction line332′ upstream of the point at whichfluid line328 is connected.Suction control device350 will be controlled by control module (not shown) and will operate to restrict suction gas flow throughsuction line332′ so that the reduced pressure downstream thereof will assist in evacuatingchamber314′ during transition from unloaded operation to loaded operation or also on initial start up ofcompressor336. In all other respects the operation including the cyclical loading and unloading ofcompressor336 will be substantially the same as described above.

Yet another embodiment is illustrated inFIG. 20 being indicated generally at352.Compressor352 includesnon-orbiting scroll member354 which is axially movably secured tomain bearing housing356 by means of a plurality ofbushings358 secured in position byfasteners360.Bushings358 andfasteners360 cooperate to accurately and non-rotatably positionnon-orbiting scroll354 while allowing limited axial movement thereof. A separate annularflanged ring362 is secured tonon-orbiting scroll354 and cooperates with a radially outwardly disposed stationaryflanged ring member364 to define a sealedseparating chamber366 therebetween.Ring member364 includes apassage368 to which one end of afluid line370 is connected, the other end of which is connected tosolenoid valve372. Similar to that described above,solenoid valve372 includesfluid lines374 and376 connected to dischargeline378 andsuction line380 respectively. The operation ofcompressor352 will be substantially identical to that described above withsolenoid valve372 operating to cyclicallyplace chamber366 in fluid communication with discharge pressure fluid and suction pressure fluid to thereby cyclically load and unloadcompressor352.

FIG. 21 represents yet afurther embodiment382 of the subject invention.Compressor382 combines the separating chamber arrangement ofcompressor352 with the suction gas supply arrangement and intermediate pressure shell ofcompressor336 shown in FIG.19. Accordingly, corresponding portions thereof are indicated by like numbers double primed and the operation thereof will be substantially the same as described above.

FIG. 22 shows a further modification of the present invention.Compressor384 is substantially the same as that shown inFIG. 16 with the exception thatcompressor384 includes a twoway solenoid valve386 connected tosuction line388 viafluid conduit390, a modified passage arrangement as described below and omitscover member269 definingupper chamber260. Accordingly, portions corresponding to like portions ofcompressor244 are indicated by like numbers double primed. Additionally, the mounting arrangement for axially movablenon-orbiting scroll258″ is substantially identical to that described with reference to FIG.20 and hence corresponding portions thereof are indicated by like numbers primed. In this embodiment solenoid valve is also connected tochamber262″ viafirst fluid line392, a second internalflexible fluid line394 and radially extendingpassage396 provided innon-orbiting scroll258″. Additionally, a plurality of separatingsprings398 are provided being positioned coaxially withbushings358′ and extending betweenmain bearing housing400 and the lower surface ofnon-orbiting scroll258″.

Under normal fully loaded operation,non-orbiting scroll258″ will be biased into sealing engagement with orbitingscroll268″ by the combined force resulting from discharge pressure acting on the upper surface ofnon-orbiting scroll258″ withinpassage254″ and intermediate pressure fluid withinchamber262″ conducted thereto viapassage266″. Under these conditions solenoidvalve386 will be in a closed position thereby preventing fluid communication betweenchamber262″ andsuction line388. When sensed system conditions indicate it is desired to unloadcompressor384,solenoid valve386 will open to thereby ventchamber262″ tosuction line388 viapassage396, andfluid lines394,392 and390 thereby relieving the intermediate biasing force onnon-orbiting scroll258″. As this biasing force is relieved, the combined force from the fluid under compression between the scroll members and the force exerted bysprings398 will operate to movenon-orbiting scroll258″ axially away from and out of sealing engagement with orbitingscroll268″ thereby unloadingcompressor384. Of course,passageway396,fluid lines394,392 and390, andsolenoid valve386 must all be sized relative to the size ofpassage266″ to ensure adequate venting ofchamber262″. Cyclical unloading and loading ofcompressor384 will be accomplished in substantially the same manner in response to system conditions as described above.

The present invention is also well suited for application to dual rotating scroll-type compressors. Such embodiments are illustrated inFIGS. 23 through 28.

Referring first toFIG. 23, a dual rotating scroll-type compressor is shown being indicated generally at402.Compressor402 includes first andsecond scroll members404,406 rotatably supported within anouter shell408 by upper andlower bearing members410,412 axially offset from each other.Upper bearing member410 is formed in aplate member415 which also serves to define adischarge chamber414 into which compressed fluid exitingdischarge port416 inupper scroll404 is directed viapassage418. Adischarge check valve420 is also providedoverlying discharge port416.Lower scroll member406 is supported within and rotatable with alower housing422. Anupper housing424 surroundsupper scroll member404, is secured tolower housing422 and cooperates withlower housing422 andupper scroll member404 to define an intermediatepressure biasing chamber426 and a separatingchamber428. Afluid passage430 is provided inupper scroll member404 extending from a compression pocket at intermediate pressure to biasingchamber426 to supply fluid pressure thereto which in combination with discharge pressure fluid acting onupper scroll member404 withinpassage418 will serve to biasupper scroll404 into sealing engagement withlower scroll member402 during fully loaded operation.

Asecond passage432 is also provided inupper scroll member404 extending from separatingchamber428 to anannular recess434 formed in the outer periphery of an uppercylindrical hub portion436 ofupper scroll404.Annular recess434 is in fluid communication with apassage438 provided inbearing410 and extending radially outwardly throughplate415.

Asolenoid valve440 is also provided the operation of which is designed to be controlled by a control module (not shown) in response to system conditions sensed by appropriate sensors (also not shown).Solenoid valve440 includes a firstfluid conduit442 connected topassage438, asecond fluid line444 connected to dischargeline448 and athird fluid line450 connected tosuction line452.

Whencompressor402 is operating under fully loaded conditions,solenoid valve440 will be in a position to place separatingchamber428 in fluid communication withsuction line452 viapassage432,recess434,passage438 andfluid lines442 and450. In order to unloadcompressor402, solenoid valve will operate to connectchamber428 to dischargeline448 thereby pressurizing same to discharge pressure. The force resulting from discharge pressure fluid inchamber428 will operate to movescroll member404 axially away from and out of sealing engagement will scrollmember402 thereby unloading the compressor. Cyclic operation of solenoid valve will result in cyclic unloading ofcompressor402 in substantially the same manner as discussed above.

FIG. 24 illustrates another embodiment of a dual rotating scroll-type compressor454 in accordance with the present invention.Compressor454 is substantially identical in construction and operation tocompressor402 with the exception thatcompressor454 does not incorporate an intermediate pressure biasing chamber but rather utilizes only discharge pressure to bias the upper axially movable scroll member into sealing engagement with the lower scroll member. Accordingly, corresponding portions thereof are indicated by the same reference numbers primed.

A further embodiment of a dual rotating scroll-type compressor456 is shown in FIG.25.Compressor456 is substantially identical tocompressors402 and454 with the exception that in place of the intermediate pressure biasing chamber provided incompressor402,compressor456 employs a plurality ofsprings458 extending between a radially inwardly extendingportion460 ofupper housing424″ and an upper surface ofupper scroll member404″. Accordingly, portions corresponding to like portions ofcompressor402 are indicated by the same reference numbers double primed.Springs458 serve to cooperate with the discharge pressure inpassage418″ to biasupper scroll member404″ axially into sealing engagement withlower scroll member402″. In all other respects the operation ofcompressor456 is substantially identical to that described above.

FIG. 26 shows a further embodiment of a dual rotating scroll-type compressor462.Compressor462 is very similar tocompressors402,454, and456 except as noted below and accordingly, like portions thereof are indicated by the same reference numbers triple primed.

Compressor462 as shown is mounted in the bottom portion of ahermetic shell464 and in an inverted position as compared tocompressors402,454 and456. Adischarge port466 is provided inscroll member406′″ and serves to discharge compressed fluid to achamber468 viacheck valve470 from which it is directed to themotor compartment472 disposed in the upper portion ofshell464 via apassage474 extending throughdrive shaft476. A driving motor is provided inmotor compartment472 and includes astator478 androtor480 secured tocrankshaft476. Axiallymovable scroll member404′″ is rotatably supported in acylindrical bearing housing482 formed in thelower end portion483 ofhousing464 and cooperates therewith to define a dischargepressure biasing chamber484. In order to supply discharge pressure fluid tochamber484, apassage486 is provided inmain bearing housing488 which is connected to asecond passage490 inlower housing portion483.Passage490 opens intochamber484 and thus conducts high pressure discharge fluid frommotor compartment472 tochamber484 tobias scroll member404′″ into sealing engagement withscroll member406′″ during normal full load operation. Asecond passage432 extends throughlower housing portion483 fromrecess434″ tofluid conduit442′″. It should be noted thatchamber484 could alternatively be pressurized with intermediate pressure fluid by providing a passage through the end plate ofscroll404′″ from a compression pocket at a pressure between suction and discharge tochamber484 thus eliminating the need forpassages486 and490. Alternatively, discharge pressure fluid could be provided tochamber484 by means of a passage through the end plate ofscroll404″ extending thereto from the control pocket into whichport466 opens.

Operation ofcompressor462 will be substantially identical to that ofcompressor454 including the cyclical loading and unloading thereof in response to actuation ofsolenoid valve440′″ as controlled by a control module and associated sensors (not shown).

FIG. 27 is directed to another embodiment of a dual rotating scroll-type compressor494 in which the lower driving scroll member is axially movable.Compressor494 includes anouter housing496 within which upper andlower scroll members498,500 are rotatably supported. Apartition plate502 is provided which separates thedischarge chamber504 from the lowersuction pressure chamber506 and also includes acylindrical bearing portion508 for rotatably supportingupper scroll member498 by means ofcylindrical portion510, the interior which also defines a dischargefluid flow path512 fromdischarge port514 pastdischarge check valve516 to dischargechamber504.Upper scroll member498 includes anannular cavity518 which opens outwardly in facing relationship tolower scroll500. An annular ring shapedpiston member520 is movably disposed therein and operative to exert a separating force onlower scroll500 in response to pressurization of the separatingchamber522 disposed abovepiston member520. In order to supply discharge pressure fluid tochamber522, apassage524 is provided inscroll member498 extending upwardly fromchamber522 throughcylindrical portion510 and opening radially outwardly therefrom into anannular recess526. Asecond passage528 extends generally radially outwardly throughplate502 and connects tofluid line530 which in turn is connected tosolenoid valve532.Solenoid valve532 also has afluid line534 extending therefrom to dischargeconduit536 and anotherfluid line538 extending therefrom tosuction line540.

Lower scroll member500 is rotatably supported vialower bearing542 and includes an internally splinedcenter hub portion544 adapted to axially movably receive a complementarilysplined drive shaft546. An intermediatepressure bleed passage548 is formed in the end plate oflower scroll member500 and serves to conduct biasing pressure fluid from an intermediate pressure compression pocket to a biasingchamber550 therebelow. Aplate member552 is secured toupper scroll498 and includes anannular recess554 in which anannular seal556 is disposed.Seal556 engages the lower surface oflower scroll500 so as to sealchamber550 from thesuction pressure chamber506.

Under fully loaded operation,lower scroll500 will be biased axially upwardly into sealing engagement withupper scroll498 due to the force from intermediate pressure fluid inchamber550. Under these conditions, solenoid valve will be in a position to placechamber522 in fluid communication withsuction line540. When system conditions indicate a lower capacity output is desired, solenoid valve will be actuated to a position to placechamber522 in fluid communication withdischarge line536 thereby pressurizingchamber522 and effecting an axial downward movement ofpiston520.Piston520 in turn will move lower scroll500 axially downwardly out of sealing engagement withupper scroll498. When solenoid valve is cycled back to a position to ventchamber522 tosuction line540, the biasing force resulting from intermediate pressure inchamber550 will returnlower scroll member500 to sealing engagement withupper scroll member498. The cyclic operation between loaded and unloaded operation will then be controlled in like manner similar to that described above by a control module and associated sensors.

FIG. 28 shows another embodiment of a dualrotating compressor558 which is substantially the same as that described with reference toFIG. 27 except as noted below. Accordingly, like portions thereof are indicated by the same reference numbers primed.Compressor558 utilizes discharge pressure fluid supplied tochamber550′ viapassage560 to biaslower scroll member500′ into sealing engagement withupper scroll member498′. Otherwise the operation ofcompressor558 is substantially identical to that described above.

Anothercompressor562 incorporating a further embodiment of the present invention is shown in FIG.29.Compressor562 is similar tocompressor352 shown inFIG. 20 except as noted below and accordingly like portions thereof are indicated by the same reference numbers triple primed.Compressor562 incorporates apartition plate564 which forms a part ofouter shell566 and separates the interior thereof into a highpressure discharge chamber568 and a lowpressure suction portion570.Partition plate564 includes a centralcylindrical portion572 which is adapted to sealingly movably receive acylindrical portion574 of non-orbiting axiallymovable scroll member354′″.Cylindrical portion574 includes a plurality ofradial openings576 which are aligned withopenings578 inportion572 to define a dischargegas flow path579 fromdischarge port580 pastdischarge check valve582 to dischargechamber568. Acover plate584 is secured tocylindrical portion574 to close off the upper end ofpassage579 and also cooperates withcylindrical portion572 to define an intermediatepressure biasing chamber586 therebetween. Afluid passage588 extends from a compression pocket at intermediate pressure tochamber586 and serves to provide fluid pressure for biasing axiallymovable scroll member354′″ into sealing engagement with orbitingscroll590. The operation including cyclical loading and unloading ofcompressor562 is substantially identical to that described with reference tocompressor352 and the other embodiments described above.

FIG. 30 illustrates acompressor592 incorporating a further modification of the present invention.Compressor592 is substantially identical tocompressor562 ofFIG. 29 except as noted below and accordingly like portions thereof are indicated by the same reference numbers quadruple primed.Compressor592 incorporates a twoway solenoid valve594 having afluid line596 connected tochamber586″″ and asecond fluid line598 connected tosuction line380″″. Additionally,member362′″ and364′″ are omitted and in lieu thereof biasingsprings600 are provided being positioned in coaxial surrounding relationship tobushings358″″.

Under fully loaded operating conditions, the biasing force resulting from intermediate fluid pressure inchamber586″″ will bias axially movablenon-orbiting scroll354″″ downwardly into sealing engagement with orbitingscroll590″″ in the same manner as discussed above and will overcome the separating force resulting fromsprings600. When conditions indicate unloading is desired,solenoid valve594 will switch from a closed condition (which prevented venting ofchamber586″″ to suction during fully loaded operation) to an open position thereby ventingchamber586″″ tosuction line380″″ and relieving the biasing force exerted onscroll354″″. As this biasing force is relieved, the force fromsprings600 together with the pressure of the fluid under compression will operate to move axiallymovable scroll member354″″ upwardly out of sealing engagement with orbitingscroll590″″. As before,solenoid valve594 will be operated in a cyclic manner by control means in response to associated sensors to cyclically load and unloadcompressor592 so as to achieve the desired degree of capacity modulation.

While the previous embodiments have been primarily directed to hermetic motor compressors, the present invention is also well suited for use with compressors employing an external drive such as for example automotive air conditioning system compressors. The use of the present invention in such an environment can eliminate the need for the expensive clutch systems commonly utilized in today's systems.

FIG. 31 illustrates acompressor602 which is specifically directed for use with an external power source.Compressor602 is similar in construction tocompressor244 ofFIG. 16 except as noted below and accordingly like portions thereof are indicated by the same reference numbers triple primed.

Compressor602 incorporates a threeway solenoid valve604 as opposed to the two way solenoid valve ofcompressor244 and hence includesfluid lines606 connected to dischargeline272′″ and asecond fluid line608 connected tosuction line610. It should be noted that a two way solenoid valve could be used in the same arrangement if desired. Becausesolenoid valve604 is designed to directly ventupper chamber260′″ tosuction line610 during unloading, continuouslyopen vent passage280 provided incompressor244 is omitted. Driveshaft612 ofcompressor602 extends outwardly ofhousing614 through suitable bearing means616 and sealing means618 and is adapted to be connected to a suitable external power source such as an automobile engine via a conventional pulley and V-belt arrangement or the like.

In operation, the external power source will continuously drivedrive shaft612 thereby effecting continuous orbital movement of orbitingscroll268′″. When system conditions indicate cooling is required,solenoid valve604 will be positioned by suitable control means to placechamber260′″ in fluid communication withsuction line610 thereby relieving any separating force resulting therefrom and enablingchamber262′″ which is supplied with intermediate pressure fluid viapassage266′″ to generate a biasing force which, with the biasing force resulting from discharge pressure fluid acting on the surface ofnon-orbiting scroll member258′″ inpassage254′″, will biasnon-orbiting scroll member258′″ into sealing engagement with orbitingscroll member268′″. When system requirements have been met,compressor602 will be unloaded by actuation ofsolenoid valve604 to a position in whichchamber260′″ is placed in fluid communication withdischarge line272′″ thereby resulting in the creation of a separating force which will operate to move non-orbiting scroll member axially out of sealing engagement with orbitingscroll member268′″. Cyclic control ofcompressor602 may be achieved in the same manner as described above thus eliminating the need for a clutch when such a system is utilized in an automotive application.

While the previous embodiments have all been directed to the use of the fluid being compressed to effect unloading of the respective compressors, the present invention may also accomplish such unloading by the use of other types of force generating means to effect axial movement of one or the other of the two scroll members. Embodiments illustrating such arrangements are shown and will be described with reference toFIGS. 32 through 34.

Referring first toFIG. 32, there is shown ahermetic compressor620 which includes ahousing622 having aplate624 operative to separate the interior thereof into adischarge chamber626 and alower portion628 at suction pressure. A bearinghousing630 is secured withinshell622 and rotatably supports acrankshaft632 which is drivenly connected to orbitingscroll member634. A non-orbiting axiallymovable scroll member636 is mounted on bearinghousing630 by means ofbushings638 andfasteners640 such thatscroll member636 is slidably movable alongbushings638 but is restrained from circumferential or radial movement.Non-orbiting scroll member636 includes apressure biasing chamber642 in the upper surface into which one end of ring shapedflanged member644 projects. The other end offlanged member644 is secured toplate624. Acylindrical portion646 ofnon-orbiting scroll member636 projects upwardly through ring shapedflanged member644 intodischarge chamber626 to define adischarge passage648 extending upwardly fromdischarge port650 viadischarge check valve652. A plurality of circumferentially spacedradial openings654 are provided adjacent the upper end ofportion646 to placepassage648 in fluid communication withdischarge chamber626. Acover plate656 is secured to the upper end ofportion646 and also includesopenings658 therein to allow passage of discharge fluid intodischarge chamber626.Non-orbiting scroll member636 also includes apassage660 extending from a compression pocket at intermediate pressure to biasingchamber642 whereby intermediate pressure fluid may be supplied tochamber642 to axially biasnon-orbiting scroll member636 into sealing engagement with orbitingscroll634 during normal fully loaded operation. Of course, this intermediate pressure biasing force will be aided by discharge pressure acting against the upper surfaces ofnon-orbiting scroll636.

In this embodiment, anunloading mechanism662 is provided which includes a suitableforce applying actuator664 supported on a cylindricalflanged support member666 which in turn is sealingly secured to a fitting668 provided on the top ofshell622. Anactuator shaft670 extends downwardly throughmember666 and fitting668 and has its lower end connected to coverplate656.Actuator664 may be any suitable type force applying capable of exerting a pulling force onnon-orbiting scroll636 such as for example an electrically actuated solenoid, a pneumatic or other fluid actuated piston and cylinder device or any other type of mechanical, magnetic, electromechanical, hydraulic, pneumatic, gas or spring type device. Operation of actuator will be controlled by asuitable control module672 in response to sensed system conditions sensed byappropriate sensors674.

As noted above, under fully loaded operating conditions, intermediate pressure fluid inchamber642 will cooperate with discharge pressure fluid inpassage648 to biasnon-orbiting scroll member636 into sealing engagement with orbitingscroll member634. When system conditions indicate unloading is desired,control module672 will effect operation ofactuator664 to exert a separating force onnon-orbiting scroll member636 thereby moving it out of sealing engagement with orbiting scroll member. When fully loaded operation is to be resumed,actuator664 will be deactuated thereby enabling the biasing force fromintermediate pressure chamber642 and discharge pressure inpassage648 to again movenon-orbiting scroll member636 into sealing engagement with orbitingscroll member634.Actuator664 will be designed to enable rapid cyclic operation so as to enable cyclical loading and unloading ofcompressor620 in the same manner as described above.

FIG. 33 shows a modified version of the embodiment ofFIG. 32 wherein like portions are indicated by the same reference numbers primed. In this embodiment,actuator664′ is located withinhousing622′ withactuating connections676 extending outwardly therefrom. In all other respects,compressor620′ will operate in the same manner as that described above with reference to FIG.32.

Referring now toFIG. 34, there is shown ahermetic compressor880 which combines certain features employed in the compressors ofFIGS. 4 and 33.Compressor880 includes anouter shell882 having aplate884 which separates the interior thereof into anupper discharge chamber886 and alower chamber888 at suction pressure. Amain bearing housing890 is disposed inlower chamber888 and serves to rotatably support adrive shaft892 which is drivenly connected to anorbiting scroll member894 also supported onmain bearing housing890. Anon-orbiting scroll member896 is axially movably secured tomain bearing housing890 and includes a cavity at the upper end thereof defined by radially inner and outercylindrical projections898,900 respectively. A flanged cylindrically shapedmember902 is sealingly secured toplate884 and extends downwardly between and movably sealingly engagesprojections898 and900 to divide the cavity into anupper separating chamber904 and a lower intermediatepressure biasing chamber906. Apassage907 innon-orbiting scroll896 operates to place biasingchamber906 in fluid communication with a fluid pocket undergoing compression and at a pressure intermediate suction and discharge. The interior ofmember902 cooperates withprojection898 to define adischarge gas flowpath908 extending fromdischarge port910 to dischargechamber886 viadischarge check valve912.

As best seen with reference toFIG. 34A, anaxially extending bore914 is provided inmember902 within which avalve member916 is axially movably disposed.Valve member916 includes a reduceddiameter portion918 adjacent the lower end thereof which, when valve member is in a first portion, operates to place separatingchamber904 in fluid communication with discharge pressure fluid inpassage908 via radially extendingpassages920 and922 and when in a second position, to place separatingchamber904 in fluid communication with suction pressure fluid inarea888 via radially extendingpassages922 and924. Additionally, aradial vent passage926 extends outwardly from the bottom ofbore914 to dischargepassage908 to facilitate movement ofvalve member916 therein.

As shown,valve member916 extends axially upwardly throughdischarge chamber886 and outwardly throughshell882 and is coupled to asuitable actuator928 secured to shell882 and which operates to move it between the first and second positions noted above. A fitting930 surroundsvalve member916 as it passes throughshell882 and contains suitable seals to prevent fluid leakage fromdischarge chamber886.Actuator928 may be any suitable device having the ability to reciprocatevalve member916 between the noted first and second positions including, for example, a solenoid or any other electrical, electromechanical, mechanical, pneumatic or hydraulically actuated device. It should also be noted that actuator may, if desired, be mounted within the interior ofshell882.

Under full load operation, intermediate fluid pressure is biasingchamber906 in cooperation with discharge pressure acting against the surface ofnon-orbiting scroll member896 inpassage908 will biasnon-orbiting scroll member896 axially into sealing engagement with orbitingscroll894. At this time,valve member926 will be in a position to place separatingchamber904 in fluid communication witharea888 at suction pressure viapassages922 and924. In order to unloadcompressor880,actuator928 will operate to movevalve member916 to a position in which it places separatingchamber904 in fluid communication with discharge pressure fluid inpassage908 viapassages920 and922 thereby pressurizingchamber904. The force resulting from pressurization ofchamber904 will move non-orbiting scroll out of sealing engagement with orbitingscroll member894 to thereby unloadcompressor880. In order to reloadcompressor880,actuator928 operates to enablevalve916 to move back to its initial position in which the discharge pressure inchamber904 will be vented toarea888 which is at suction pressure viapassages922 and924 thereby enabling intermediate pressure inchamber906 and discharge pressure fluid inpassage908 to move non-orbiting scroll back into sealing engagement with orbitingscroll894. Cyclical time pulsed actuation ofactuator928 will thus enable the capacity ofcompressor880 to be modulated in substantially the same manner as described above.

FIG. 35 shows a further variation of the embodiments shown inFIGS. 32 and 33. In this embodiment,compressor678 includes anon-orbiting scroll680 which is fixedly mounted to bearinghousing682 and orbitingscroll member684 is designed to be axially movable.Compressor678 includes a suitable force applying means686 in the form of an annular electromagnetic coil secured to bearinghousing682 in a well688 provided therein in underlying relationship to orbitingscroll member684. A suitable magneticallyresponsive member690 is positioned within force applying means686 and bears against the undersurface of orbitingscroll member684. In this embodiment, actuation of force applying means686 operates to exert an axially upwardly directed force on orbitingscroll member684 thereby urging it into sealing engagement withnon-orbiting scroll member680. Unloading ofcompressor678 is accomplished by deactuating force applying means686 thus relieving the biasing force generated thereby and allowing the separating force from the fluid under compression to move orbitingscroll member684 out of sealing engagement with orbitingscroll member680. Cyclic time pulsed loading and unloading may be easily accomplished by controlling force applying means686 in substantially the same manner as described above.

It should be noted that whilecompressor678 has been described utilizing an electromagnetic force applying means, other suitable force applying means may be substituted therefor including mechanical, magnetic, electromechanical, hydraulic, pneumatic, gas or mechanical spring type devices.

The prior embodiments of the present invention have all been directed to various means for effecting unloading by axial separation of the respective scroll members. However, the present invention also contemplates accomplishing unloading by radial separation of the flank surfaces of the scroll wraps thereby providing a leakage path between the compression pockets. Embodiments illustrating this method of unloading are shown and will be described with reference toFIGS. 36 through 44.

Referring now toFIG. 36, a compressor incorporating radially directed unloading is shown being indicated generally at692.Compressor692 is generally similar to the previously described compressors and includes anouter shell694 having adischarge chamber696 andlower chamber698 at suction pressure. A bearinghousing700 is supported withinshell694 and has anon-orbiting scroll member702 axially movably secured thereto and anorbiting scroll704 supported thereon which is adapted to be driven bycrankshaft706. An intermediatepressure biasing chamber708 is provided at the upper end ofnon-orbiting scroll member702 which is supplied with intermediate pressure fluid from a compression pocket viapassage710 to thereby axially bias non-orbiting scroll member into sealing engagement with orbitingscroll member704.

Bearinghousing700 includes a plurality of substantially identical circumferentially spacedchambers712 within each of which apiston714 is movably disposed. Eachpiston714 includes apin716 projecting axially upwardly therefrom, throughopening718 in the upper surface of bearinghousing700 and into corresponding axially aligned opening720 provided innon-orbiting scroll member702. Aspring722 is provided in each of theopenings720 and extends between acylindrical spring retainer724 secured tonon-orbiting scroll702 and the upper end of each of thepins716 and serves to exert an axially downwardly directed biasing force thereon. As shown, each of thepins716 includes anupper portion726 of a first diameter and alower portion728 of a greater diameter.Pins716 are positioned in surrounding relationship to the periphery of orbitingscroll704. Anannular manifolding assembly729 is secured to the lower portion ofmain bearing700 and closes off the lower end ofrespective chambers712.Manifolding assembly729 includes anannular passage731 from which respectiveaxially extending passages733 open upwardly into each of thechambers712.

As best seen with reference toFIG. 37,eccentric pin730 ofcrankshaft706 is drivingly connected to orbiting scroll member by means of abushing732 rotatably disposed withinhub734 provided on orbitingscroll704.Bushing732 includes a generally oval shapedopening736 having a flat738 along one side thereof which is adapted to receiveeccentric pin730 which also includes a flat740 engageable with flat738 through which the driving forces are transmitted to orbitingscroll704. As shown, opening736 is sized such that bushing and associatedorbiting scroll704 may move relative to each other such that the orbiting radius through which orbiting scroll moves may be reduced from a maximum at which the flank surfaces of the scroll wraps are in sealing engagement with each other to a minimum distance at which the flank surfaces are spaced from each other.

Compressor692 also includes a threeway solenoid valve742 having afluid line744 connected toannular passage731, asecond fluid line746 connected tosuction line748 and athird fluid line750 connected to dischargeline752.

Under fully loaded operation,solenoid valve742 will be in a position so as to place each of thechambers712 in fluid communication withsuction line748 viapassages733,passage731, andfluid lines744 and746. Thus, each of the pistons and associated pins will be held in a lowered positioned bysprings722 whereby orbiting scroll member will be free to orbit at its full maximum radius. As axially movablenon-orbiting scroll702 is biased into sealing engagement with orbitingscroll704 by biasingchamber708,compressor692 will operate at full capacity. In order to unloadcompressor692, solenoid valve will be actuated so as to placedischarge line752 in fluid communication withannular chamber731 which in turn will pressurize each of thechamber712 with discharge pressure fluid to urge each of thepistons714 and associatedpins716 to move axially upwardly to a fully raised position as shown in FIG.39. Because the force of the discharge pressure fluid acting on therespective pistons714 will not be sufficient to overcome the forces urging the orbiting scroll radially outwardly, pins716 will move upwardly sequentially as the orbiting scroll moves away therefrom. Once all of the pins have moved upwardly, thelarge diameter portion728 ofpins716 will be in a position to engage thearcuate cutouts754 provided around the periphery of orbitingscroll member704 as best seen with reference toFIG. 38 thereby causing the orbiting radius of orbitingscroll member704 to be reduced to a minimum at which the flank surfaces thereof are no longer in sealing relationship and the compressor is fully unloaded. It should be noted that thepins716 will be circumferentially spaced such that at least two adjacent pins will be in engagement withcorresponding cutouts754 throughout the orbit of orbitingscroll member704. When loaded operation is to be resumed, solenoid valve will be returned to a position in whichchamber712 is vented tosuction line748 viapassages733,731 andfluid lines744 and746 thereby allowingsprings722 to bias each of thepins716 and associatedpistons714 downwardly to a position in which reduceddiameter portion726 of the respective pins is positioned in radially spaced relationship tocutouts754 and orbitingscroll704 is able to resume its full orbital radius and full capacity compression will resume.

FIG. 40 shows a modified version of the embodiment ofFIGS. 36 through 39 at756 wherein a twoway solenoid valve758 is utilized havingfluid lines760 and762 connected tochamber712 anddischarge line752′ respectively. In this embodiment, each of thechambers712 includes apassage764 at the lower end thereof that is in continuous communication withlower portion698′ ofshell694′ which is at suction pressure. Thus, each of thechambers712′ will be continuously vented to suction. To unloadcompressor756, solenoid valve is opened thereby placing each of thechambers712′ in fluid communication with discharge pressure fluid fromdischarge line752′ and biasing each of thepistons714′ into a raised position. The remaining portions ofcompressor756 are substantially identical to those ofcompressor692 and accordingly are indicated by the same reference numbers primed. Similarly, the operation ofcompressor756 will in all other respects be substantially identical to that ofcompressor692.

A further modification of the embodiments shown inFIGS. 36 through 40 is shown inFIGS. 41 and 42 at766. In this embodiment,cutout portions754 are deleted and twocircular openings768 are provided in lieu thereof. Likewise, only twopins716″ are provided. The diameter ofcircular openings768 relative to the reduceddiameter portion726″ ofpins714″ will be such that there will be a slight clearance therebetween when orbitingscroll member704″ is orbiting at its maximum orbiting radius. When thelarger diameter portion728″ ofpins716″ are moved intoholes768, the orbiting radius of orbitingscroll704″ will be reduced to a minimum thus interrupting the sealing relationship between the flank surfaces of the scroll wraps.

Additionally, in this embodiment, springs722 have been replaced by an intermediate pressure biasing arrangement including apassage770 inscroll member702″ extending from intermediatepressure biasing chamber708″ into the upper end ofmember724″. Thus, pins716″ will be biased to a lowered position by means of intermediate fluid pressure. In all other respects the construction and operation ofcompressor766 will be substantially identical tocompressor692 and hence corresponding portions have been indicated by the same reference numbers used inFIG. 35 double primed.

Another arrangement for radially unloading a scroll-type compressor is shown inFIGS. 43 and 44.Compressor772 is generally similar in construction tocompressor692 and includes anouter shell774 having apartition plate776 dividing the interior thereof into anupper discharge chamber778 and alower portion780 at suction pressure. A main bearing housing is secured withinlower portion780 and includes afirst member782 to which axially movablenon-orbiting scroll member784 is secured by means ofbushings786 andfasteners788 and which also axially supports orbitingscroll member790. Asecond member792 of main bearing housing is secured to the lower end ofmember782, rotatably supports a drivingcrankshaft794 and together withfirst portion782 and orbitingscroll member790 defines a substantiallyclosed cavity796. Orbitingscroll member790 includes acenter hub797 having a conically shaped outer surface which is adapted to drivingly mate with aneccentric pin798 provided oncrankshaft794 via adrive bushing800 disposed therebetween.Pin798 and drive bushing800 are substantially identical to that shown in FIG.37 and allow for variation in the orbiting radius of orbitingscroll member790 between a maximum at which the flank surfaces of the wraps are in sealing engagement and a minimum at which the flank surfaces of the wraps are spaced apart.

Non-orbiting scroll member784 includes a cavity at the upper end thereof in which a floatingseal member802 is disposed to define an intermediatepressure biasing chamber804 which is supplied with fluid under compression at a pressure between suction and discharge viapassage806 to thereby axially biasnon-orbiting scroll member784 into sealing engagement with orbitingscroll member790. The upper end of floatingseal802 sealingly engagesplate776 and cooperates withnon-orbiting scroll member784 to define a dischargefluid flow path808 fromdischarge port810 to dischargechamber778 viadischarge check valve812 andopening814 inplate776.

Apiston member816 is axially movably disposed withincavity796 and includes suitable seals to thereby define a sealedseparating chamber818 at the lower end ofcavity796. A plurality ofsprings820 extend from a radially inwardly extendingflange portion822 ofmember782 intosuitable wells824 provided inpiston member816 and serve to biaspiston member816 axially downwardly away fromhub portion797. Additionally,piston member816 includes a conically shaped radially inwardly facingsurface826 at the upper end thereof which is adapted to engage and is complementary to the outer conical surface ofcenter hub797.

As shown, a threeway solenoid valve828 is also provided which is connected to separatingchamber818 viafluid line830, tosuction line832 viafluid line834 and to dischargeline836 viafluid line838. It should be noted, however, that a two way solenoid valve connected only to suction could be substituted for threeway solenoid828. In such a case, a bleed hole from thebottom chamber818 throughmember792 opening intoarea780 would be required to vent discharge pressure fluid in somewhat similar manner to that described with reference to FIG.38.

Under full load operation,solenoid valve828 will be in a position so as to place separatingchamber818 in fluid communication withsuction line832 viafluid lines830 and834 thereby maintainingchamber818 at substantially suction pressure. The action ofsprings820 will maintain piston member in its axially lowered position as shown inFIG. 41 at whichconical surface826 thereof will be slightly spaced from the outer conical surface ofhub796 ofsolenoid scroll member790.

When unloading is desired,solenoid valve828 will be actuated to a position to placedischarge line836 in fluid communication with separatingchamber818 viafluid lines838 and830 thereby pressurizingchamber818 to substantially discharge pressure. The biasing force resulting from this pressurization ofchamber818 will operate to movepiston816 axially upwardly overcoming the biasing force ofsprings820 and movingconical surface826 into engagement with the outer conical surface ofhub796 of orbitingscroll member790. Continued upward movement ofpiston816 to a position as shown inFIG. 44 will result inconical surface826 reducing the orbiting radius of orbitingscroll member790 such that the flank surfaces of the wraps thereof are no longer in sealing engagement with the flank surfaces of the non-orbiting scroll member and further compression of fluid ceases. In order to resume compression, solenoid valve is actuated to a position to ventchamber818 tosuction line832 viafluid lines830 and834 thereby enablingsprings820 tobias piston member816 into its lowered position as shown in FIG.43.

It should be noted that whilecompressor772 has been shown as includingsprings820 tobias piston816 axially downwardly, it may be possible to delete these biasing members in some applications and to rely on the axial component of the force exerted onpiston818 by the engagement ofconical surface826 with the conical surface onhub796 to cause movement of piston member away from orbitingscroll member790. Additionally,solenoid valve828 is intended to be controlled in a cyclical manner by means of acontrol module8080″ and associatedsensors8282″ in response to varying system conditions in substantially the same manner as described above with respect to the other embodiments.

It should also be noted that the features incorporated in the various embodiments described above should not be viewed as being restricted to use only in that embodiment. Rather, features of one embodiment may be incorporated into another embodiment in addition to or in lieu of the specific features disclosed with respect to that other embodiment. For example, the discharge check valve provided on the outer shell of some of the embodiments may be substituted for the discharge check valve provided adjacent the discharge port in other embodiments or vice versa. Likewise, the suction control module disclosed for use with the embodiment ofFIGS. 19 and 21 may also be incorporated into other embodiments. Further, while in many embodiments, the solenoid valve and associated fluid lines have been shown as positioned outside of the shell, they may be located within the shell if desired.

In each of the above embodiments, it is intended that the orbiting scroll continue to be driven while the compressor is in an unloaded condition. Obviously, the power required to drive the orbiting scroll member when the compressor is unloaded (no compression taking place) is considerably less than that required when the compressor is fully loaded. Accordingly, it may be desirable to provide additional control means operative to improve motor efficiency during these periods of reduced load operation thereof.

Such an embodiment is shown schematically inFIG. 45 which comprises amotor compressor840 having asolenoid valve842 connected to dischargeline844 viafluid line846 and asuction line848 viafluid line850 and being operative to selectively place a compressor unloading mechanism in fluid communication with either the suction line or discharge line viafluid line852.Solenoid valve842 is intended to be controlled by acontrol module854 vialine855 in response to system conditions sensed bysensors856. As thus far described, the system represents a schematic illustration of any of the embodiments described above, it being noted thatsolenoid valve842 could be a two way solenoid valve in lieu of the three way solenoid valve arrangement shown. In order to improve efficiency of the driving motor during reduced load operation, amotor control module858 is also provided which is connected to the compressor motor circuit vialine860 and to controlmodule854 vialine862. It is contemplated thatmotor control module858 will operate in response to a signal fromcontrol module854 indicating that the compressor is being placed in an unloaded operating condition. In response to this signal, motor control module will operate to vary one or more of the compressor motor operating parameters to thereby improve its efficiency during the period of reduced load. Such operating parameters are intended to include any variably controllable factors which affect motor operating efficiency including voltage reduction or varying the running capacitance of the motor for example. Oncecontrol module854 signalsmotor control module858 that the compressor is being returned to fully loaded operation, motor control module will then operate to restore the affected operating parameters to maximize motor efficiency under full load operation.

The above described compressor unloading arrangements are particularly well suited to provide a wide range of capacity modulation in a relatively inexpensive and effective manner and to maximize the overall efficiency of the system as compared to prior capacity modulation arrangements. However, under some operating conditions such as those encountered when condenser inlet pressure is at a reduced level, it may be desirable to reduce the compression ratio of the compressor to avoid over-compression of the refrigerant at certain levels of system capacity reduction.

FIG. 46 illustrates acompressor864 which incorporates both the advantages of a cyclical or pulsed unloading as described above with means for reducing the compression ratio of the compressor so as to thereby increase the ability of the compressor to maximize efficiency under any operating conditions.Compressor864 is substantially identical tocompressor10 shown in and described with reference toFIG. 1 except as noted below and accordingly like portions thereof are indicated by the same reference numbers primed.

Compressor864 includes a pair ofports866,868 innon-orbiting scroll member32′ which open intocompression pockets870,872 respectively.Ports866 and868 communicate with apassage874 opening outwardly through the outer periphery ofnon-orbiting scroll member32′ into thelower area876 ofshell12′ which is at suction pressure. Suitable valve means878 are provided to selectively control communication ofports866,868 witharea876. Preferably,ports866,868 will be located in an area such that they will begin to be in communication with the respective compression pockets prior to the compression pockets being sealed off from the suction fluid supply fromarea876.

In operation, when it is determined that a reduction in compressor capacity is desired, a determination will also be made from the system operating conditions if the compressor is operating in an over-compression mode or an under-compression mode. If it is determined that an over-compression mode is present, initial capacity reduction will most efficiently be carried out by opening valve means878 which will thus placepockets870,872 in fluid communication witharea876 ofcompressor864 which is at suction pressure. The effect of openingvalve878 is thus seen as reducing the operating length of the wraps as compression does not begin until the respective pockets are closed off from the supply of suction gas. As the volume of the pockets when they are closed off whenports866,868 are open toarea876 is less than ifports866,868 were closed, the compression ratio of the compressor is reduced. This then will eliminate or at least reduce the level of over-compression. If additional capacity reduction is required afterports866,868 have been opened, the cyclic pulsed unloading ofcompressor864 may be initiated in the same manner as described above.

If it is initially determined that the compressor is operating either in an under-compression mode or a point between an under and over-compression mode, reducing the compression ratio thereof will only result in decreased efficiency. Therefore, under these conditions, the cyclic pulsed unloading ofcompressor864 will be initiated in the same manner as described above while valve means878 and henceports866,868 remain in a closed position.

In this manner, the overall efficiency of the system may be maintained at a high level regardless of the operating conditions being encountered. It should be noted that whileFIG. 46 shows the delayed suction method of capacity modulation incorporated with the embodiment ofFIG. 1, it may also be utilized in conjunction with any of the other embodiments disclosed herein. Also, while the delayed suction method of capacity modulation illustrated shows only the use of a single step provided by a single set of ports, it is possible to incorporate multiple steps by providing multiple ports any number of which may be opened depending on the system operating conditions. Also, the specific valving and porting arrangement shown should be considered exemplary only as there exist many different arrangements by which capacity modulation may be achieved via a delayed suction approach. Any number of these known delayed suction approaches may be utilized in place of the arrangement shown. It should also be noted that the arrangement for controlling motor efficiency under reduced load conditions as described with reference toFIG. 45 may also be incorporated into the embodiment of FIG.46.

While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to provide the advantages and features above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

Claims (15)

1. A scroll-type compressor comprising:

a bearing housing;

a first scroll member movably supported on said bearing housing, said first scroll member including a first end plate and a first spiral wrap provided on one side thereof;

a second scroll member supported on said bearing housing, said second scroll member including a second end plate and a second spiral wrap provided on one side thereof;

a drive member;

a radially compliant coupling drivingly connecting said drive member to said first scroll member whereby said drive member operates to orbit said first scroll member with respect to said second scroll member at a first orbiting radius wherein said first and second spiral wraps are intermeshed and define sealed moving fluid pockets which decrease in size as they move from a radially outer position to a radially inward position;

a chamber;

a pin member movably disposed in said chamber, said pin member being movable from a first position at which said first scroll member orbits at said first orbiting radius and a second position in which said pin member restricts the orbiting radius of said first scroll member to a magnitude less than said first radius whereby leakage paths are formed between said moving fluid pockets; and

a drive system for reciprocating said pin between said first and second positions to thereby modulate the capacity of said compressor.

2. A scroll-type compressor as set forth inclaim 1 wherein said drive system reciprocates said pin in a time pulsed manner.

3. A scroll-type compressor as set forth inclaim 2 wherein said drive system operates to move said pin member to said first position for a first predetermined time period and to said second position for a second predetermined time period.

4. A scroll-type compressor as set forth inclaim 3 further comprising a sensor connected to a control module and operative to provide a signal thereto indicative of operating conditions, said control module being operative to control the duration of said first and second time periods to maximize the efficiency of said compressor for said operating conditions.

5. A scroll-type compressor as set forth inclaim 1 further including a plurality of chambers and a plurality of pin members movably disposed in each of said chambers, said drive system being operative to reciprocate each of said pin members between said first and second positions.

6. A scroll-type compressor as set forth inclaim 1 wherein said leakage path is sufficient to reduce the capacity of said scroll machine to substantially zero.

7. A scroll-type compressor as set forth inclaim 1 wherein said drive system is actuated by fluid pressure.

8. A scroll-type compressor as set forth inclaim 1 further comprising a motor for driving said drive member and a motor controller operative to vary an operating parameter of said motor in response to a signal indicative of movement of said pin into said second position to thereby improve the efficiency of said motor while the capacity of said compressor is reduced.

9. A scroll-type compressor as set forth inclaim 1 further comprising a passage opening into at least one of said moving fluid pockets and operative to vent said pocket to a lower pressure area of said compressor, a valve for opening and closing said passage and a control module to control operation of said valve.

10. A scroll-type compressor as set forth inclaim 9 wherein said control module includes at least one sensor operative to sense if said compressor is operating in an over-compression mode and to provide a signal indicative thereof to said control module, said control module being operative to actuate said valve in response to said signal to thereby reduce the compression ratio of said compressor.

11. A scroll-type compressor comprising:

a hermetic shell;

a bearing housing supported within said shell;

a first scroll member movably supported on said bearing housing, said first scroll member including a first end plate and a first spiral wrap provided on one side thereof;

a second scroll member supported on said bearing housing, said second scroll member including a second end plate and a second spiral wrap provided on one side thereof;

a drive shaft rotatably supported by said bearing housing, said drive shaft including an eccentric;

a radially compliant coupling for drivingly connecting said drive shaft to said first scroll member whereby rotation of said drive shaft operates to orbit said first scroll member with respect to said second scroll member at a first orbiting radius with said first and second spiral wraps intermeshed and defining sealed moving fluid pockets which decrease in size as they move from a radially outer position to a radially inward position;

a plurality of chambers provided in spaced relationship in said bearing housing;

a plurality of pin members, one of said plurality of pin members being movably disposed in each of said chambers, said pin members being movable from a first position at which said first scroll member orbits at said first orbiting radius and a second position in which said pin members restrict the orbiting radius of said first scroll member to a magnitude less than said first radius whereby leakage paths are formed between said moving fluid pockets; and

a drive system for reciprocating said pins between said first and second positions in a time pulsed manner to thereby modulate the capacity of said compressor.

12. A scroll-type compressor as set forth inclaim 11 wherein each of said pin members extends through an opening in said first end plate.

13. A scroll-type compressor as set forth inclaim 11 wherein said drive system includes a fluid passage for selectively connecting said chambers to compressed fluid being discharged from said compressor to drive said pin members from said first position to said second position.

14. A scroll-type compressor as set forth inclaim 13 wherein each of said chambers includes a vent passage to vent said discharge pressure fluid into said shell.

15. A scroll-type compressor as set forth inclaim 13 wherein said drive system includes a valve for controlling fluid flow through said passage, said valve also being operative to place said chambers in fluid communication with a suction inlet of said compressor.

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