CA1333480C - Scroll machine with plural pressurized seal enhancing chambers and static vane mounts - Google Patents
Scroll machine with plural pressurized seal enhancing chambers and static vane mountsInfo
- Publication number
- CA1333480C CA1333480C CA000616406A CA616406A CA1333480C CA 1333480 C CA1333480 C CA 1333480C CA 000616406 A CA000616406 A CA 000616406A CA 616406 A CA616406 A CA 616406A CA 1333480 C CA1333480 C CA 1333480C
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- scroll
- type machine
- pressure
- scroll member
- fluid
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Abstract
There is disclosed a scroll-type machine particularly suited for use as a refrigerant compressor and incorporating an improved suspension system for the non-orbiting scroll whereby the latter may be pressure baised for the purpose of augmenting tip sealing. The machine also has a modified wrap tip and end plate profile in order to enhance performance , as well as an improved lubrication system for the drive and a baffle arrangement to provide a directed suction inlet. The machine also has an Oldham coupling utilizing a novel ring element which is non-circular and provides for increased thrust-bearing size, or reduced machine size. There is also disclosed a method of manufacture of a scroll-type machine.
Description
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BACKGROUND AND SUMMARY
The present invention relates to fluid displacement apparatus and more particularly to an improved scroll-type machine especially adapted for compressing gaseous fluids, and to a method of manufacture thereof.
This application is a division of our Canadian application Serial No. 544,673 filed August 17, 1987.
A class of machines exists in the art generally known as "scroll" apparatus for the displacement of various types of fluids. Such apparatus may be configured as an expander, a dis-placement engine, a pump, a compressor, etc., and many features of the present invention are applicable to any one of these machines.
For purposes of illustration, however, the disclosed embodiments are in the form of a hermetic refrigerant compressor.
Generally speaking, a scroll apparatus comprises two spiral scroll wraps of similar configuration each mounted on a separate end plate to define a scroll member. The two scroll mem-bers are interfitted together with one of the scroll wraps being rotationally displaced 180 degrees from the other. The apparatus operates by orbiting one scroll member (the "orbiting scroll") with respect to the other scroll member (the "fixed scroll" or "non-orbiting scroll") to make moving line contacts between the flanks of the respective wraps, defining moving _l_ ~
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isolated crescent-shaped p x kets of fluid. m e spirals are c~ nly formed as involutes of a circle, and ideally there is no relative rotation between the scroll m_l~e~s during operation, i.e., the motion is purely curvilinear translation (i.e. no rotation of any line in the body). m e fluid pockets carry the fluid to be handled from a first zone in the scroll apparatus where a fluid inlet is provided, to a second zone in the apparatus where a fluid outlet is provided. m e volume of a sealed pocket changes as it moves from the first zone to the second zone. At any one instant in time there will be at least one pair of sealed pockets, and when there are several pairs of sealed pockets at one time, each pair will have different volumes. In a o~ ~Lessor the ~eoor~ zone is at a higher pressure than the firs~t zone and is physically located centrally in the apparatus, the first zone being located at the outer periphery of the apparatus.
Two types of contacts define the fluid pockets formed between the scroll members: axially extending tangential line contacts between the spiral faces or flanks of the wraps caused by radial forces ("flank t- s~aling"), and area contacts caused by axial forces bet~Een the plane edge surfaces (the "tips") of each wrap and the opposite end plate ("tip sealing"). For high efficiency, good sealing must be achieved for both types of contacts, however, the present invention is primarily ooncerned with tip sealing.
The c~cep~ of a scroll-type apparatus has thus been known for ~ame time and has been reco~iz~ as having distinct adv-~tayes. For example, scroll machines have high is~Lro~ic and volumetric ~ffiçi~cy, and hence are relatively small and lightweight for a given capacity.
They are quieter and more vibration free than many ~I~L~SS~L~ hec~ e ` -1333~83 they do not use large reciprocating parts (e.g. pistons, col~ecLing rods, etc.), and kecAllce all fluid flow is in one direction with simultaneous compression in plural o~osed pockets there are less pressure-created vibrations. Such machines also tend to have high reliability and durability because of the relative few moving parts utilized, the relative low velocity of movement between the scrolls, and an ~he~ forgiveness to fluid contamination.
One of the difficult areas of design in a scroll-type machine concerns the technique used to achieve tip sealing under all operating conditions, and also speeds in a variable speed machine. Colr~tionally this has been Arccmrlished by (1) using ~L~ ~ly accurate _nd very e~ sive machining tech~;~ues, (2) providing the wrap ~ips with spiral tip seals, which unfortunately are hard to A~s~mhle and often unreliable, or (3) applying an axial ~es~.ing force by axial biasing the orbiting scroll toward the non-orbiting scroll using compressed working fluid. The latter technique has some advantages but also es~,Ls problems; namely, in addition to providing a Les~ling force to balance the axial separating force, it is also ~ essAry to balance the tipping mo~ on the scroll .,~l~e~ due to press~.e ~ene~ated radial forces, as well as the inertial loads resulting from its orbital motion, both of which are speed ~e~nd~nt. Thus, the axial balancing force must be relatively high, and will be optimal at only one speed.
One of the more imFortant features of applicant's invention ~ C~lS the provision of a desisn for overcom m g these problems. It resides in the discov~ of a unique axially oompliant ~ on system for the n~n oL~iting scroll which fully balances all significant t;~p;~
mov~læ~l~s. mis permits pressure biasing of the 1~1l o.biting scroll 133348~
(which has no inertial load problems), the amount of such pressure biasing re~uired being limited to the minimum amount necessAry to deal solely with axial separating forces, thus significantly and beneficially reducing the amount of restoring f ~ e required. While pressure biasing of the ~n o~biting scroll member has been broadly suggested in the art (see U.S. patent No. 3,874,827), such systems suffer the same disadvantages as those which bias the orbiting scroll member insofar as dealing with tipping mo~ ~n s is o~ ."e~. Furthe~"~re, applicants' alLa~ provides a control ~over non-axial n~ of the ~IJ olbiting scroll member which is greatly superior to that of prior art devices. Several different ~m~impnts of applicants' invention are disclosed, using different suspension means and difè~ sources of pressure.
One of the more popular approaches for preventing relative angular movement between the scrolls as they orbit with .~s~ecL to one another resides in the use of an Oldham coupling operative between the orbiting scroll and a fixed portion of the apparatus. An Oldham coupling typically comprises a circular Oldham ring having two sets of keys, one set of keys slides in one direction on a surface of the orbiting scroll while the other set of keys slides at rights angles U~eLe~ on a surface of the ~rh;~e h~c;~. m e Oldham ring is generally ~icposed around the outside of the thrust bearing which s~olLs the orbital scroll member with LeS~eC~ to the housing. Another feature of applicant's invention resides in the provision of an in~L~d non-circular Oldham ring which permits the use of a larger thrust bearing, or a reduced diameter outer shell for a given size thrust ~aring .
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The machlne of the present lnventlon also embodles an lmproved dlrected suctlon baffle for a refrlgerant compressor whlch prevents mlxlng of the suctlon gas wlth oll dlspersed throughout the lnterlor of the compressor shell, whlch functlons as an oll separator to remove already entralned oll, and whlch prevents the transmlsslon of motor heat to the suctlon gas, thereby slgnlflcantly lmprovlng overall efflclency.
The machlne of thls lnventlon also lncorporates an lmproved lubrlcatlon system to lnsure that adequate lubrlcatlng oll ls dellvered to the drlvlng connectlon between the crankshaft and orbltlng scroll member.
Another feature of the present lnventlon concerns the provlslon of a unlque manufacturlng technlque, and wrap tlp and end plate proflle, whlch compensate for thermal growth near the center of the machlne. Thls facllltates the use of relatlvely fast machlnlng operatlons for fabrlcatlon and ylelds a compressor whlch wlll reach lts maxlmum performance ln a much shorter break-ln tlme perlod than conventlonal scroll machlnes.
Accordlng to a broad aspect of the lnventlon there ls provlded a scroll-type machlne comprlslng~
~ a) A flrst scroll member havlng a splral wrap thereon;
(b) a second scroll member havlng a splral wrap thereon;
(c) support means for mountlng sald scroll members wlth sald splral wraps lntermeshlng wlth one another, sald flrst scroll member belng mounted for non-orbltal movement wlth respect to sald support means, and sald second scroll member belng mounted for ~A
.
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orbltal movement wlth respect to sald flrst scroll member whereby sald orbltal movement wlll cause sald wraps to deflne movlng fluld pockets communlcatlng between a low pressure and a hlgh pressure;
and (d) blaslng means for blaslng sald flrst scroll member toward sald second scroll member, sald blaslng means comprlslng means deflnlng a flrst chamber contalnlng fluid at a flrst pressure; and means deflnlng a second chamber contalning a fluld at a second pressure;
sald flrst and second pressures belng greater than sald low pressure;
said flrst and second chambers belng posltloned such that sald fluld at sald flrst pressure and sald fluld at sald second pressure cooperate to exert a blaslng force on sald flrst scroll member ln a dlrectlon toward sald second scroll member and generally parallel to the axls of sald orbltal movement to thereby enhance seallng therebetween.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
Flgure 1 1B a vertlcal sectlonal vlew, wlth certaln parts broken away, of a scroll compressor embodylng the prlnclples of the present lnventlon, wlth the sectlon belng taken generally along llne 1-1 ln Flgure 3 but havlng certaln parts sllghtly rotateds Flgure 2 ls a slmllar sectlonal vlew taken generally along llne 2-2 ln Flgure 3 but wlth certaln parts sllghtly rotated;
5a ~ A
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Figure 3 is a top plan view of the o~ Lessor of Figures 1 and 2with part of the top removed;
Figure 4 is a view similar to that of Figure 3 but with the entire upper assembly of the compressor removed;
Figures 5, 6 and 7 are f~ay~ ary views similAr to the right hand portion of Figure 4 with s~cc~csive parts removed to more clearly show the details of construction thereof;
Figure 8 is a LLay,~n~ary section view taken generally along line 8-8 in Figure 4;
Figure 9 is a LLa, ntary section view t~ken generally along line 9-9 in Figure 4;
Figure 10 is a sectional view taken generally along line 10-10 in Figure 1;
Figures llA and llB are developed spiral vertical sectional views t2ken generally along lines llA-llA and llB-llB, respectively, in Figure 10, with the profile shown being fo~esllo.~,e~ and greatly exd~y~ated;
Figure 12 is a developed sectional view taken generally along line 12-12 in Figure 10;
Figure 13 is a top plan view of an improved Oldham ring forming part of the ~,es~,~ invention;
Figure 14 is a side elevational view of the Oldham ring of Figure li;
Figure 15 is a f~ay~ ary sectional view taken substantially along line 15-1~ in Figure 10 showing several of the lubrication pcS~ ways;
Figure 16 is a sectional view taken substantially along line 16-16 in Figure 15;
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Figure 17 is a horizontal sectional view t2ken substantially along line 17-17 in Figure 2;
Figure 18 is an enlarged fragmentary vertical sectional view illustrating another ~mho~iment of the ~es~ L invention;
Figure 19 is a view s;milAr to Figure 18 showing a further ~mho~im~t;
Figure 20 is a f~y,h~ary somewhat di~y~ ,atic horizontal sectional view illustrating a different technique for mounting the o~Liting scroll for limited axial oompliance;
Figure 21 is a sectional view taken subs~ ially along line 21-21 in Figure 20;
Figure 22 is a sectional view si~;lAr to Figure 2~0, but showing a further technique for mounting the non-orbiting scroll for limited axial oompliance;
Figure 23 is a view similar to Figure 20, but illustrating a another technique for mounting the r,o1l olbiting scroll for limited axial oompliance;
Figure 24 is a sectional view taken substantially along line 24-24 in Figure 23;
Figure 25 is simil~r to Figure 20 and illustrates yet a further terh~ique for mounting the non o~biting scroll for limited axial ~,~liance;
Figure 26 is a sectional view taken substantially along line 26-26 in Figure 25;
Figure 27 is ~;m;lAr to Figure 20 and illusLLa~es yet ~oL~e~
te~h~;que for mounting the non o.biting scroll for limited axial oompliance;
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Figure 28 is a sectional view taken substantially along line 28-28 in Figure 27;
Figure 29 is similar to Figure 20 and illustrates yet a further technique for mounting the non-orbiting scroll for limited axial compliance;
Figure 30 is a sectional view taken substantially along line 30-30 in Figure 29:
Figures 31 and 32 are views sim;lAr to Figure 20, illustrating two additional somewhat similar techniqués for mounting the l~on o~biting ~oll for limited axial compliance; and Figure 33 is a view s;m;lAr to Figure 20 illustrating diay~ ically yet another technique for mounting ~he rol. o-biting scroll for limited axial compliance.
DESCRIPTIoN OF THE ~k~Kh~ EMBODIMENTS
Although the principles of the present invention may be applied to many different types of scroll-type machines, they are described herein for exemplary p~l~oses Pmhc~;Pd in a hermetic scroll-type o~l~.ess~l, and particuarly one which has been found to have specific utility in the oompression of refrigerant for air conditioning and refrigeration systems.
With reference to Figures 1-3, the machine comprises three major overall units, i.e. a central ~cs~mhly 10 hol~ce~ within a circular cylindrical steel shell 12, a top _nd bo~,l A-cs~mhl j~s 14 and 16 welded to the upper and lower ends of shell 12, L~s~Lively, to close and seal same. Shell 12 houses the m, jor ~ll~o~ s of the r-^~h;~e, generally including an electric motor 18 having a stator 20 (with conventional ~.~
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windinqs 22 and pLo~ec or 23) press fit within shell 12, m~tor rotor 24 (with ~ ional luqs 26) heat shrunk on a crankshaft 28, a o~ ess~
body 30 preferably welded to shell 12 at a plurality of circumferentially spaced locations, as at 32, and supportinq an orbiting scroll memker 34 having a scroll wrap 35 of a standard desired flank profile and a tip surface 33, an upper crankshaft hQArinq 39 of conventional two-piece bearing o~ns~l~ction, a ~ o~biting axially compliant scroll ,.~,~ 36 having a scroll wrap 37 of a standard desired flank profile (preferably the same~as that of scroll wrap 35) meshing with wrap 35 in the usu_l manner and a tip surface 31, a ~;schArge port 41 in scroll member 36, an Oldh_m ring 38 ~ispos~ ~etween scroll nember 34 and body 30 to prevent rotation of scroll member 34, a suction inlet fittinq 40 soldered or welded to shell 12, a directed suction Acs~hly 42 for directinq suction gas to the O~~ eSSGL inlet, and a lower bearinq support bracket 44 welded at each end to shell 10, as at 46, and supportinq a lower crankshaft bearing 48 in which is journaled the lower end of crankshaft 28. The lower end of the oompressor constitutes a sump filled with lubricatinq oil 49.
~ ower Acs~mhly 16 oomprises a simple steel stamping 50 having a plurality of feet 52 and apertured mounting flanges 54. Stamping 50 is ~lded to shell 12, _s at 56, to close and seal the lower end thereof.
Upper assembly 14 is a ~i~ohA~ge muffler comprising a lower stamped steel closure member 58 welded to the upper end of shell 10, as at 60, to close and seal same. Closure member 58 has an u~s ~ding peripheral flange 62 from which projects an apertured holding lug 64 (Figure 3), and in its central area def;n~s an axially ~;sposed circular cylinder chamber 66 having a plurality of openings 68 in the wall 1333~
thereof. To incre~se its stiffness memker 58 is provided with a plurality of embossed or ridged areas 70. An annular gas dicchArge chamber 72 is defined above member 58 by means of an annular muffler member 74 which is welded at its outer periphery to flange 62, as at 76, and at its inner periphery to the outside wall of cylinder chamber 66, as at 78. C~"~ressed gas from ~icrharge port 41 passes through openings 68 into ~hAmhpr 72 from which it is normally ~isrh~rged via a discharge fitting 80 soldered or brazed into the wall of member 74. A
conventional internal pressure relief valve ACS~mhly 82 may be mounted in a suitable opening in closure ,~,~x~ 58 to vent discharge gas into shell 12 in ex oe ssive pressure situations.
Considering in greater detail the major parts of ~he ~ ,~essor, crankshaft 28, which is rotationally driven by motor 18, has at its lower end a reduced diameter bearing surfa oe 84 journaled in bearing 48 and supported on the shoulder above surface 84 by a thrust washer 85 (Figures 1, 2 and 17). The lower end of bearing 48 has an oil inlet passage 86 and a debris removal passage 88. n~ et 44 is formed in the ~hape shown and is provided with ups~a~ side flanges 90 to increase the sLL~ ~Lh and stiffness ~heleof. Eearing 48 is lubricated by immersion in oil 49 and oil is pum~ed to the remainder of the compressor by a c~.lv~l~ional centrifugal crankshaft pump comprising a central oil p~sA~ge 92 and an eccer.tLic, outwardly inçl;ne~, oil feed p~CcAge 94 communicating therewith and extending to the top of the crankshaft. A
transverse p~CsAge 96 extends from pacs~ge 94 to a CiL~ en ial grocve 98 in bearing 39 to lubricate the latter. A lower counterweight 97 and an upper counterweight 100 are afflxed to crankshaft 28 in any suitable manner, such as by staking to projections on lugs 26 in the ) usual manner (n~t shown). These counterweights ~re of conventiona design for a scroll-type machine.
Orbiting scroll member 34 comprises an end plate 102 having generally flat parallel upper and lower surfaces 104 and 106, respectively, the latter slidably engaging a flat circular thrust bearing surface 108 ~ on body 30. Thrust bearing surface 108 is lubricated by an annular groove 110 which receives oil from F~Csage 94 in crankshaft 28 via r~cs~ge 96 and groove 98, the latter communicating with a~.oLhel groove 112 in bearing 39 which feeds oil to intersecting F~c~g~s 114 and 116 in body 30 (Figure 15). m e tips 31 of scroll wrap 37 sealingly engage surface 104, and the tips 33 of scroll wrap 35 in turn sealingly engage a generally flat and parallel ~surface 117 on scroll member 36.
Integrally depending from scroll l~,L~ 34 is a hub 118 having an axial bore 120 therein which has rotatively journaled therein a circular cylindrical unloading drive bushing 122 having an axial bore 124 in B
which is drivingly ~jcpos~ an eccen~Lic crank pin 126 integrally formed ~ ~mf~li4 at the upper end of crankshaft 28. The drive is radially ~ t,~
with crank pin 126 driving bushing 122 via a flat surface 128 on pin l26 which slidably engages a flat bearing insert 130 ~icpose~ in the wall of bore 124. Rotation of crankshaft 28 causes bushing 126 to rotate about the crankshaft axis, which in turn causes scroll ~ L~ 34 to move in a circular orbital path. The angle of the flat driving surface is chosen so that the drive introduces a slight centrifugal force ~ ~ n~ to the orbiting scroll, in order to enhance flank sealing. Bore 124 is cylidrical, but is also slightly oval in cross-sectional shape to permit limited relative sliding movement between the pin and bushing, which ` -1333~
will in turn permit automatic separation and hence unloading of the meshing scroll flanks when liquids or solids are ingested into the o~ essor.
The radially compliant orbital drive of the present invention is lubricated utilizing an improved oil feeding system. Oil is pumped by pump passage 92 to the top of passage 94 from which it is thrown radially outwardly by centrifugal for oe , as indicated by dotted line 125. The oil is collected in a recess in the form of a radial groove 131 located m the top of bushing 122 .along path 125. From here it flows downwardly into the clearance space between pin 126 and bore 124, and between bore 120 and a flat surface 133 on bushing 122 which is aligned with groove 131 (Figure 16). EX oe ss oil then dr~ains to the oil sump 49 via a F~ss~ge 135 in bcdy 30.
Rotation of scroll member 34 relative to body 30 and scroll member 36 is prevented by an Oldham coupling, comprising ring 38 (Figures 13 and 14) which has two downwardly projecting diametrically c~y~s~ integral keys 134 slidably ~ispose~ in diametrically opposed radial slots 136 in body 30, and at 90 degrees therefrom twv upwardly projecting ~ ically l~S~ integral keys 138 slidably ~;spose~ in diametrically q.~lose~ radial slots 140 in scroll member 34 (one of which is shown in Figure 1).
Ring 38 is of a unique configuration whereby it permits the use of a maximum size thrust bearing for a given overal} m.~chine size (in transverse eloss sec~ion), or a m;ni~ size m.~achine for a given size thrust bearinq. miS is accomplished by taking adv~.~age of the fact that the Oldham ring m~ves in a straight line with ~ea~eC~ to the o~"~Lessor bcdy, and thus configuring the ring with a generally oval or 1333~80 "racetrack" shape of minimum inside dimension to clear the peripheral edge of the thrust bearing. m e inside peripheral wall of ring 38, the controlling shape in the present invention, comprises one end 142 of a radius R taken from center x and an opposite end 144 of the same radius R taken from an outer ~ (Figure 13), with the intermediate wall portions being substantially straight, as at 146 and 148. Center points x and y are spaced apart a distance equal to twice the orbital radius of scroll member 34 and are located on a line passing through the centers of keys 134 and radial slots 136, and radiu5 R is equal to the radius of thrust b~ring surface 108 plus a ~lede~ermlned rin;~ cl ance. Except for the shape of ring 38, the Oldham coupling functions in the conventional manner.
One of the more significant aspects of the ~les~-L invention resides in the unique suspension by which upper non-orbiting scroll member is mounted for limited axial mc~ t, while being restrained from any radial or rotational movement, in order to permit axial pressure biasing for tip sealing. m e preferred technique for accomplishing this is best shown in Figures 4-7, 9 and 12. Figure 4 shows the top of the compressor with top ACs~mhly 14 removed, and Figures 5-7 show a p~cyLessive removal of parts. On each side of o~"~Lessor body 30 there are a pair of axially projecting posts 150 having flat upper surfaces lying in a common transverse plane. & roll member 36 has a peripheral flange 152 having a transversely ~;~pose~
planar upper surfa oe , which is ~ æ ess~1 at 154 to accommodate posts 150 (Figures 6 and 7). Posts 150 have axially extending threaded holes 156, and flange 152 has co~es~nding holes 158 equally gpaced from holes 156.
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Dispose~ on top of posts 150 is a flat soft metal gasket 160 of the shape shown in Figure 6, on top of gasket 160 is a flat spring steel leaf spring 162 of the shape shown in Figure 5, and on top of that is a retainer 164, all of the these parts being clamped together by threaded fas~e~s 166 threadably ~;~posed in holes 156. The outer ends of spring 162 are affixed to flange 152 by threaded fasteners 168 disposed in holes 158. The opposite side of scroll member 36 is identically supported. As can thus be visualized, scroll member 36 can move slightly in the axial direction by flexing and sLLe~ling (within the elastic limit) springs 162, but cannot rotate or move in the radial ion.
Maximum axial m~ nt of the scroll nembers in a eparating direction is limited by a mechanical stop, i.e. the en~A~ t of flange 152 (see portion 170 in Figures 6, 7 and 12) against the lower surface of spring 162, which is backed-up by retainer 164, and in the opposite d;rection by en~ r -nt of the scroll wrap tips on the end plate of the opposite scroll member. This mer-h~ic~l stop o~e~a~es to cause the oomp esso~ to still compress in the rare situation in which the axial separating force is greater than the axial restoring force, as is the case on start-up. The maximum tip clearance permitted by the stop can be relatively small, e.g. in the order of less than .005" for a scroll to 3n-4" diameter and 1"-2" in wrap height.
Prior to final Ass~mhly scrol} memker 36 is ~Lo~elly aligned with ~es~c~ to body 30 by means of a fixture (not shown) having pins insertable within locating holes 172 on bcdy 30 and locating holes 174 on flange 152. Posts 150 and gasket 160 are provided with ~uLs~ ially Ali~ned edges 176 ~ ose~ generally ~e~ lAr to the portion of `- 1333~80 pring 162 extending thereover, for the purpose of reducing stresses Lhe~ ~ -. Gasket 160 also ~ to distribute the clamping load on spring 162. As shown, spring 162 is in its unstressed condition when the scroll 11~1~ is at its maximum tip clearance condition (i.e. against retainer 164), for ease of manufacture. Pe~u~e the stress in spring 162 is so low for the full range of axial movement, however, the initial essed axial design position of spring 162 is not believed to be critical.
What is very significant, h~v~r, is that the transverse plane in which spring 162 is ~icrosed, as well as the surfaces on the body and n~ll o~iting scroll memker to which it is attached, are disposed substantially in an imaginary transverse plane passing through the mid-point of the meshing scroll wraps, i.e. ap~loAimately mid-way between surfaces 104 and 117. m is enables the mounting means for the axially compliant scroll n~l~eL to minimize the tipping mo~ent on the scroll member caused by the C~ r essed fluid acting in a radial I direction, i.e. the pressure of the oom~less~ gas acting radially against the flanks of the spiral wraps. Failure to h~ e this tipping moment could result in unseating of scroll member 36. This technique for balancinq this force is qreatly superior to the use of the axial pressure biasing her~uce it reduces the possibility of over-biasing the scroll members toqether and hpc~l~ce it also makes tip seal biasing substantially independent of compressor speed. m ere may remain a small tippinq movement due to the fact that the axial separating for oe does not act exactly on the center of the crankshaft, hK~,ev~r it is relatively insignificant compared to the separating and ~e~LvLing forces no~r~ly encountered. There is therefore a distinct advantage in -) 1 3 3 3 ~ ~ ~
axially biasing the non o~iting scroll member, as compared to the orbiting scroll member, in that in the case of the latter it is rCcessAry to ~,~ensate for tipping mc~ s due to radial separating forces, as well as those due to inertial forces, which are a function of speed, and this can result in ex oe ssive balancing forces, particularly at low speeds.
The mounting of scroll .~ e~ 36 for axial compliance in the p~esen~ manner permits the use of a very simple pressure biasing a-~any~,~ to augment tip sealing. With the present invention this is accomplished using pumped fluid at discharge pressure, or at an e~,~diate pressure, or at a pressure refIecting a combination of both. In its simpler and pLes~.~ly preferred form, axiàl biasing in a tip sealing or Les~oLing direction is achieved using dic~hArge pressure.
As best seen in Figures 1-3, the top of scroll member 36 is provided with a cylindrical wall 178 surrounding ~;~chArge port 39 and defining a piston slidably ~;-cpose~ in cylinder chamber 66, an elas~ ric seal 180 being provided to enhance sealing. Scroll member 36 is thus hj~Ced in a ~s~bLing direction by c~ essed fluid at discharge pressure acting on the area of the top of scroll ,~,~x~ 36 defined by piston 178 (less the area of the ~js~hArge port).
FecAIlce the _xial separating force is a function of the A;cchArge pressure of the machine (among other things), it is possible to choose a piston area which will yield excellent tip sealing under most operating conditions. Preferably, the area is c~os~, so that there is no sis~if;cAnt separation of the scroll members at any time in the cycle during normal operating conditions. FL~ . . o~e, optimally in a maximum 1333~8~
pressure situation (maximum separating force) there would be a minimum net axial balancing for oe , and of course no significant ~eparation.
With respect to tip sealing, it has also been discovered that significant perfo~,2nce improvements with a minimum break-in period can be achieved by slightly altering the configuration of end plate surfaces 104 and 117, as well as scroll wrap tip surfaces 31 and 33. It has been learned that it is much preferred to form each of the end plate surfaces 104 and 117 so that they are very slightly concave, and if wrap tip surfaces 31 and 33 are s;~;lArly configured (i.e. surface 31 is t generally parallel to surfa oe 117, and surface 33 is generally parallel to surface 104). This may be contrary to what might be predicted hecAllce it results in an initial distinct axial clearance between the scroll memkers in the central area of the machine, which is the highest pressure area; however it has been found that hPrAll~e the central area is also the hottest, there is more thermal growth in the axial direction in this area which would otherwise result in ~xcPssive efficiency robbing frictional rubbing in the central area of the compressor. By providing this initial extra clearance the com~Lesso- reaches a maximum ' tip sealing condition as it reaches operating temperature.
Although a theoretically smooth concave surface may be better, it has been discovered that the surface can be forrcd having a stepped spiral configuration, which is much easier to machine. As can best be seen in gossly e~y~a~ed form in Figures llA and llB, with reference to Figure 10, surface 104, while being generally flat, is actually formed of spiral stepped surfaces 182, 184, 186 and 188. Tip surface 33 is similarly configured with spiral steps 190, 192, 194 and 196. The individual steps should be as small as possible, with a total 1333~
displacement from flat being a function of scroll wrap height and the thermal coefficient of expansion of the material used.
For example, it has been found that in a three-wrap machine with cast iron scroll members, the ratio of wrap or vane height to total axial surface displacement can range from 3000:1 to 9000:1, with a preferred ratio of approximately 6000:1. Prefer-ably both scroll members will have the same end plate and tip surface configurations, although it is believed possible to put all of the axial surface displacement on one scroll member, if desired. It is not critical where the steps are located because they are 80 small (they cannot even be seen with the naked eye), and because they are 80 small the surfaces in question are referred to as "generally flat". This stepped surface is very different from that of another scroll-type machine in which relatively large steps (with step sealing between the mated scroll members) are provided for increasing the pressure ratio of the machine.
In operation, a cold machine on start-up will have tip sealing at the outer periphery, but an axial clearance in the center area. As the machine reaches operating temperature the axial thermal growth of the central wraps will reduce the axial clearance until good tip sealing is achieved, such sealing being enhanced by pressure biasing as described above. In the absence of such initial axial surface displacement, thermal growth in the center of the machine will cause the outer wraps to axially separate, with 1088 of a good tip seal.
-18a-13334~0 The compressor of the present invention is also provided with improved means for directing suction gas entering the shell directly to the inlet of the compressor itself. ThiS
advantageously facilitates the -18b-~- l33~lsa separation of oil from inlet suction fluid, as well as prevents inlet suction fluid from picking up oil dispersed within the shell interior.
It also prevents the suction gas from picking up ~.fi~ssAry heat from Un~
the motor, which would cause reduction in ve~unc~td-y-efficiency.
A The directed suction A~-cs~ly 42 oomprises a lower baffle element 200 formed of sheet metal and having circumferentially spaced vertical flanges 202 welded to the inside surface of shell 12 (Figures 1, 4, 8 and 10). Baffle 200 is positioned directly over the inlet from suction fitting 40 and is provided with an open bottom portion 204 so that oil carried in the entering suction gas will impinge upon the baffle and then drain into compressor sump 49. The ~cs~ly furth OE comprises a molded plastic element 206 having a ~ ~r~rdly depe~ding integrally formed arcuate shaped channel section 208 extending into a space between the top of baffle 200 and the wall of shell 12, as best seen in Figure 1. The upper portion of element 206 is generally tllh~ r in configuration (diverging radially inwardly) for communicating gas flowing up channel 208 radially inwardly into the p ripheral inlet of the meshed scroll members. Element 208 is retained in place in a circ~,~e~.Lial direction by means of a notch 210 which straddles one of the fasteners 168, and axially by means of an integrally formed tab 212 which is stressed against the lower surface of closure menber 58, as best shown in Figure 1. Tab 212 operates to resiliently bias element 206 axially ~ rdly into the position shown. The radially outer extent of the directed suction inlet ra~a~eway is defined by the inner wall s~rf~ce of shell 12.
Power is supplied to the o~.~Lessol motor in the normal manner using a c~ ional terminal block, ~Lo~ec~ed by a suitable cover 214.
, 1 133~4g~
Several alternative ways in which to achieve pressure biasing in an axial direction to enhance tip se~ are illusLLa~a~ in Figures 18 A ~19 where parts having like functions to those of the first ~o~ nt are indicated with the same reference numerals.
In the ~hc~iment of Figure 18 axial biasing is achieved through the use of c~"~essed fluid at an intenmediate pressure less than ~ hArge pressure. This is Aoco~rlished by providing a piston 300 on the top of scroll member 36 which slides in cylinder ~hAmh~r 66, but which has a closure element 302 preventing ~osl~re of the top of the piston to ~iC~hArge pressure. Instead discharge fluid flows from ~isch~rge port 39 into a radiaI rPc~Age 304 in piston 300 which oDl~ec~s with an annular groove 306, which is in direct com~unication with openings 68 and discharge ~hAmhPr 72. Elastomeric seals 308 and 310 prcvide the necess~ry sealing. Ca"~Lessed fluid under an intermediate pressure is tapped from the desired sealed p x ket defined by the wraps via a p~CsAge 312 to the top of pistons ioo, where it exerts an axial .es~o~ing force on the non-orbiting ccroll member to e~hAn~-e tip Eealing.
In the er~o~imPnt of Figure 19 a oombination of ~i~oh~rge and intermediate pressures are utilized for axial tip seal biasing. To acc~,~lish this, closure memker 58 is ~har~ to define two separate OQAX~A~ SraCe~ cylinder cbambers 314 and 316, and the top of scroll member 36 is provided with cc~xi~l pistons 318 and 320 slidably disposed in ~lu ,~s 314 and 316 ~s~Lively. CbmpLessed fluid under ~ic~Arge pressure is applied to the top of piston 316 in exactly the ~ame manner as in the first er}xlL~nent, and fluid under an intermediate pressure is applied to annular piston 318 via a rAssa~e 322 extending from a 1333~g~
suitably located pressure tap. If desired, piston 320 could be ~ubjected to a second intermediate pressure, ~a~he~ than ~isrhArge pressure. Pec~A~lce the areas of the pistons and the location of the pressure tap can be varied, this ~hcdiment offers the best way to achieve optimum axial balancing for all desired operating conditions.
The pressure taps can be chosen to provide the desired pressure and if des~red can be located to see diLe~ pressures at diLfe~ent points in the cycle, so that an _~e~a~e desired pressure can ke obtained. Pressure r~ss~s 312, 322 and the like are ~,efe~ably relatively small in diameter so that there is a min;~rn of flow (and hence pumping loss~ and a ~mr~n;ng of pressure ~and hence f~rce) variations.
In Figures 20 through 33, there are illustrated a number of other svcFPn~;on systems which have been disc-~vt~ed mounting the non-orbiting scroll member for limited axial mo~ Æ~,~, while restraining same from a radial and circumferential movement. Each of these ~m~c~;ments functions to mount the ~n oLbiting scroll member at its mid-point, as in the first Pm~c~;ment, so as to hp~An~e the ~ ;n~ mDments on the scroll memher cleaLed by radial fluid ~.es~uLe forces. In all of these em~xxluments, the top surface of flange 152 i8 in the same 9~ -Llical position as in the first emkadiment.
" With ~fe~ence to Figures 20 and` 21, D~l~yOL~ iS maintained by means of a spring steel ring 400 ~ oL~ at its outer p_riphery by n~ans of faster.ers 402 to a ~ur.ting ring 404 affixed to the inside surface of shell 12, and at its ir.side periphery to the ~er surface of flange 152 c~ "on oll,iting scroll m~rber 36 ~y means of asL~--e~s 406.
Rir~ 400 is provided wi~ a plurality of anS~led c~Pn;~s 408 ~i~posed 1333~80 about the full ext~ent thereof to reduce the stiffness thereof and permit limited axial excursions of the no~ o~Liting scroll member 36. PecA~lce cpenings 408 are slanted with Le~ cL to the rA~iAl direction, axial displa oe ment of the inner periphery of the ring with ~s~L to the outer periphery heleof ~not require ~L~t~ nq of the ring, but will cause a very slight rotation. This very limited rotational m n~ment is so trivial, hK~.evcr, that it is not believed it causes any significant loss of efficiency.
In the Pr~c~iment of Figure 22, 1~1. oLbitinq scroll 36 is very ~imply mounted by means of a plurality of Lr~re~ ~Lac~c~s 410 welded on one leg to the inner surface of shell 12 and having the other leg affixed to the upper surface of flange 152 by n~u~s of a ~uitable fastener 412. Bracket 410 is desiqned so that it may sLLe~ch sliqhtly within its elastic limit to Ac~ te axial excursions of the o~biting scroll.
In the ~ko~;m~nts of Fiqures 23 and 24, the mounting means comprises a plurality (three shown) of ~lhlllAr members 414 having a radially inner flange structure 416 affixed to the top ~urface of flange 152 of the Ib~ oLbiting scroll by means of a ~uitable ~s~ ~ 418, and a radially outer flanqe 420 o~.u ~ La~ by means of a suitable fas~,e~
422 to a ~ac~e~ 424 ~ P~ to the ;~cide ~rf~ oe of shell 12. Radial exoursions of the l~ Lbiting scroll are ~.ev~ e!d by virtue of the fact that there are a plurality of ~llhl~l~r members u~ e~ with at least two of them not dire!ctly opposi~ one ~x~LheL.
In the emho~ment of Figures 25 and 26, the lX~ Liting scroll is supported for limited axial .~.~ by means of leaf springs 426 and 428 which are affixed at their outer ends to a mounting ring 430 welded 13334~0 ;
to the inside surface of shell 12 by suitable fas~ene~s 432, and to the upper surface of flange 152 in the center Lhe~e~r by means of a ~uitable fastener 434. The leaf springs can either be straight, as in the case of spring 426, or arcuate, as in the case of spring 428. Slight axial excursions of scroll ._,L~ 36 will cause sL.e~.ing of the leaf springs within their elastic limit.
In the er~QdimPnt of Figures 27 and 28 radial and circumferential movement of ~lol~ o~biting scroll 36 is prevented by a plurality of spherical balls 436 (one shown) tightly fit within a cylindrical bore defined by a cylindrical surfa oe 43~ on the inner peripheral edge of a mounting ring 440 ~ e~ to the inside surface of shell 12 and by a cylindrical surfa oe 439 formed in the radially outer peripheral edge of 4~
a flange ~ on ~ biting scroll member 36, the balls 436 lying in a plane ~;s~osed midway between the end plate surfaces of the scroll .~ ~e s for the reasons discussed above. m e ~mho~;~.rnt of Figures 29 and 30 is virtually identical to that of Figures 27 and 28 except instead of balls, there are ut;lj7~d a plurality of circular cylindrical rollers 444 ~one of which is shcwn) tightly ~.~ssed within a ~e~Lar~lar slot defined by surface 446 on ring 440 and surface 448 on flange 442.
Preferably ring 440 is sufficientlyl resilient that it can be stLe~led over the balls or rollers in order to ~,~ sLLess the ~cse~hly and eliminate any backlash.
In the em~c~;m~nt of Figure 31, the orbiting scroll 36 is provided with a centrally ~;~rosçd flange 450 having an axially ~xL~ding hole 452 extending th~eL~.-ough. S~ qly ~crQse~ within hole 452 is a pin 454 tightly affixed at its lower end to bcdy 30. As can be ~isualized, axial exc~rsions of the ~ o~iting scroll are 1333~0 possible whereas circ~,~e~tial or radial excursions are prevented.
The ~mhc~;mPnt of Figure 32 is identical to that of Figure 1 except that pin 454 is adjustable. mis is accomplished by providing an enlarged hole 456 in a suitable flange on body 30 and providing pin 4S4 with a Cupport flange 458 and a threaded lower end projecting through hole 456 and having a threaded nut 460 thereon. Once pin 454 is accurately positioned, nut 460 is tightened to pe~"~)en-ly anchor the parts in position.
In the P~ho~im~t of Figure 33, the lnside ~rface of shell 12 is provided with two bosses 462 and 464 having accurat~ely m~ch;n~d, radially inwardly facing flat surfaces 466 and 468, l~5~t~ ively, -cposed at right angles with respect to one another.. Flange 152 on ~ o~biting scroll 36 is provided with two corresponding bosses each having radially outwardly facing flat surfaces 470 and 472 located at right angles with respect to one another and engaging surfaces 466 and 468, respectively. These bosses and surfaces are accurately machined so as to properly locate the lon o~Biting scroll in the proper radial and rotational position. To maintain it in that position while permitting limited axial movement thereof there is provided a very stiff spring in the form of a Belleville washer or the like 474 acting~ n a boss 476 on the inner surface of shell 12 and a boss 478 ~ffiY~1 to the outer periphery of flange 152. Spring 484 applies a strong biasing force against the non-orbiting scroll to maintain it in position against surfaces 466 and 468. This force should be slightly greater than the maximum radial and rotational force normally enco~.~_L~d tending to unseat the scroll member. Spring 474 is preferably positioned so that the ~iasing force it exerts has equal components in the direction of each of hosses 462 and 464 ~i.e., its diametrical force line bisects the two bosses). As in the previous ~mhC~iments~ the hosses and spring force are ~jspose~ substantially midway between the scroll member end plate surfaces, in order to balance tipping moments.
In all of the ~mhc~ nts of Figures 20 through 33 it should be a~ æ iated that axial movement of the llOl~ oL~iting scrolls in a ~separating direction can be limited by any suitable means, such as the mechanical stop described in the first embodiment. Mk~ ~n~ in the opposite direction is, of course, lim~ted by the ~1~J~J-~ent of the scroll m~ ~eLs with one anoL~.eL.
While it will be apparent that the ~L~feLLed embcdiments of the invention disclosed are well calculated to provide the advantages and features above stated, it will be a~.eoiated that the invention is sllsceptible to modification, variation and rhA~e without departing from the ~-o~e~ scope or fair meaning of the subjoined claims.
BACKGROUND AND SUMMARY
The present invention relates to fluid displacement apparatus and more particularly to an improved scroll-type machine especially adapted for compressing gaseous fluids, and to a method of manufacture thereof.
This application is a division of our Canadian application Serial No. 544,673 filed August 17, 1987.
A class of machines exists in the art generally known as "scroll" apparatus for the displacement of various types of fluids. Such apparatus may be configured as an expander, a dis-placement engine, a pump, a compressor, etc., and many features of the present invention are applicable to any one of these machines.
For purposes of illustration, however, the disclosed embodiments are in the form of a hermetic refrigerant compressor.
Generally speaking, a scroll apparatus comprises two spiral scroll wraps of similar configuration each mounted on a separate end plate to define a scroll member. The two scroll mem-bers are interfitted together with one of the scroll wraps being rotationally displaced 180 degrees from the other. The apparatus operates by orbiting one scroll member (the "orbiting scroll") with respect to the other scroll member (the "fixed scroll" or "non-orbiting scroll") to make moving line contacts between the flanks of the respective wraps, defining moving _l_ ~
i 1333~
isolated crescent-shaped p x kets of fluid. m e spirals are c~ nly formed as involutes of a circle, and ideally there is no relative rotation between the scroll m_l~e~s during operation, i.e., the motion is purely curvilinear translation (i.e. no rotation of any line in the body). m e fluid pockets carry the fluid to be handled from a first zone in the scroll apparatus where a fluid inlet is provided, to a second zone in the apparatus where a fluid outlet is provided. m e volume of a sealed pocket changes as it moves from the first zone to the second zone. At any one instant in time there will be at least one pair of sealed pockets, and when there are several pairs of sealed pockets at one time, each pair will have different volumes. In a o~ ~Lessor the ~eoor~ zone is at a higher pressure than the firs~t zone and is physically located centrally in the apparatus, the first zone being located at the outer periphery of the apparatus.
Two types of contacts define the fluid pockets formed between the scroll members: axially extending tangential line contacts between the spiral faces or flanks of the wraps caused by radial forces ("flank t- s~aling"), and area contacts caused by axial forces bet~Een the plane edge surfaces (the "tips") of each wrap and the opposite end plate ("tip sealing"). For high efficiency, good sealing must be achieved for both types of contacts, however, the present invention is primarily ooncerned with tip sealing.
The c~cep~ of a scroll-type apparatus has thus been known for ~ame time and has been reco~iz~ as having distinct adv-~tayes. For example, scroll machines have high is~Lro~ic and volumetric ~ffiçi~cy, and hence are relatively small and lightweight for a given capacity.
They are quieter and more vibration free than many ~I~L~SS~L~ hec~ e ` -1333~83 they do not use large reciprocating parts (e.g. pistons, col~ecLing rods, etc.), and kecAllce all fluid flow is in one direction with simultaneous compression in plural o~osed pockets there are less pressure-created vibrations. Such machines also tend to have high reliability and durability because of the relative few moving parts utilized, the relative low velocity of movement between the scrolls, and an ~he~ forgiveness to fluid contamination.
One of the difficult areas of design in a scroll-type machine concerns the technique used to achieve tip sealing under all operating conditions, and also speeds in a variable speed machine. Colr~tionally this has been Arccmrlished by (1) using ~L~ ~ly accurate _nd very e~ sive machining tech~;~ues, (2) providing the wrap ~ips with spiral tip seals, which unfortunately are hard to A~s~mhle and often unreliable, or (3) applying an axial ~es~.ing force by axial biasing the orbiting scroll toward the non-orbiting scroll using compressed working fluid. The latter technique has some advantages but also es~,Ls problems; namely, in addition to providing a Les~ling force to balance the axial separating force, it is also ~ essAry to balance the tipping mo~ on the scroll .,~l~e~ due to press~.e ~ene~ated radial forces, as well as the inertial loads resulting from its orbital motion, both of which are speed ~e~nd~nt. Thus, the axial balancing force must be relatively high, and will be optimal at only one speed.
One of the more imFortant features of applicant's invention ~ C~lS the provision of a desisn for overcom m g these problems. It resides in the discov~ of a unique axially oompliant ~ on system for the n~n oL~iting scroll which fully balances all significant t;~p;~
mov~læ~l~s. mis permits pressure biasing of the 1~1l o.biting scroll 133348~
(which has no inertial load problems), the amount of such pressure biasing re~uired being limited to the minimum amount necessAry to deal solely with axial separating forces, thus significantly and beneficially reducing the amount of restoring f ~ e required. While pressure biasing of the ~n o~biting scroll member has been broadly suggested in the art (see U.S. patent No. 3,874,827), such systems suffer the same disadvantages as those which bias the orbiting scroll member insofar as dealing with tipping mo~ ~n s is o~ ."e~. Furthe~"~re, applicants' alLa~ provides a control ~over non-axial n~ of the ~IJ olbiting scroll member which is greatly superior to that of prior art devices. Several different ~m~impnts of applicants' invention are disclosed, using different suspension means and difè~ sources of pressure.
One of the more popular approaches for preventing relative angular movement between the scrolls as they orbit with .~s~ecL to one another resides in the use of an Oldham coupling operative between the orbiting scroll and a fixed portion of the apparatus. An Oldham coupling typically comprises a circular Oldham ring having two sets of keys, one set of keys slides in one direction on a surface of the orbiting scroll while the other set of keys slides at rights angles U~eLe~ on a surface of the ~rh;~e h~c;~. m e Oldham ring is generally ~icposed around the outside of the thrust bearing which s~olLs the orbital scroll member with LeS~eC~ to the housing. Another feature of applicant's invention resides in the provision of an in~L~d non-circular Oldham ring which permits the use of a larger thrust bearing, or a reduced diameter outer shell for a given size thrust ~aring .
1333~8~
The machlne of the present lnventlon also embodles an lmproved dlrected suctlon baffle for a refrlgerant compressor whlch prevents mlxlng of the suctlon gas wlth oll dlspersed throughout the lnterlor of the compressor shell, whlch functlons as an oll separator to remove already entralned oll, and whlch prevents the transmlsslon of motor heat to the suctlon gas, thereby slgnlflcantly lmprovlng overall efflclency.
The machlne of thls lnventlon also lncorporates an lmproved lubrlcatlon system to lnsure that adequate lubrlcatlng oll ls dellvered to the drlvlng connectlon between the crankshaft and orbltlng scroll member.
Another feature of the present lnventlon concerns the provlslon of a unlque manufacturlng technlque, and wrap tlp and end plate proflle, whlch compensate for thermal growth near the center of the machlne. Thls facllltates the use of relatlvely fast machlnlng operatlons for fabrlcatlon and ylelds a compressor whlch wlll reach lts maxlmum performance ln a much shorter break-ln tlme perlod than conventlonal scroll machlnes.
Accordlng to a broad aspect of the lnventlon there ls provlded a scroll-type machlne comprlslng~
~ a) A flrst scroll member havlng a splral wrap thereon;
(b) a second scroll member havlng a splral wrap thereon;
(c) support means for mountlng sald scroll members wlth sald splral wraps lntermeshlng wlth one another, sald flrst scroll member belng mounted for non-orbltal movement wlth respect to sald support means, and sald second scroll member belng mounted for ~A
.
1333~
orbltal movement wlth respect to sald flrst scroll member whereby sald orbltal movement wlll cause sald wraps to deflne movlng fluld pockets communlcatlng between a low pressure and a hlgh pressure;
and (d) blaslng means for blaslng sald flrst scroll member toward sald second scroll member, sald blaslng means comprlslng means deflnlng a flrst chamber contalnlng fluid at a flrst pressure; and means deflnlng a second chamber contalning a fluld at a second pressure;
sald flrst and second pressures belng greater than sald low pressure;
said flrst and second chambers belng posltloned such that sald fluld at sald flrst pressure and sald fluld at sald second pressure cooperate to exert a blaslng force on sald flrst scroll member ln a dlrectlon toward sald second scroll member and generally parallel to the axls of sald orbltal movement to thereby enhance seallng therebetween.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
Flgure 1 1B a vertlcal sectlonal vlew, wlth certaln parts broken away, of a scroll compressor embodylng the prlnclples of the present lnventlon, wlth the sectlon belng taken generally along llne 1-1 ln Flgure 3 but havlng certaln parts sllghtly rotateds Flgure 2 ls a slmllar sectlonal vlew taken generally along llne 2-2 ln Flgure 3 but wlth certaln parts sllghtly rotated;
5a ~ A
!
-1333~8~
Figure 3 is a top plan view of the o~ Lessor of Figures 1 and 2with part of the top removed;
Figure 4 is a view similar to that of Figure 3 but with the entire upper assembly of the compressor removed;
Figures 5, 6 and 7 are f~ay~ ary views similAr to the right hand portion of Figure 4 with s~cc~csive parts removed to more clearly show the details of construction thereof;
Figure 8 is a LLay,~n~ary section view taken generally along line 8-8 in Figure 4;
Figure 9 is a LLa, ntary section view t~ken generally along line 9-9 in Figure 4;
Figure 10 is a sectional view taken generally along line 10-10 in Figure 1;
Figures llA and llB are developed spiral vertical sectional views t2ken generally along lines llA-llA and llB-llB, respectively, in Figure 10, with the profile shown being fo~esllo.~,e~ and greatly exd~y~ated;
Figure 12 is a developed sectional view taken generally along line 12-12 in Figure 10;
Figure 13 is a top plan view of an improved Oldham ring forming part of the ~,es~,~ invention;
Figure 14 is a side elevational view of the Oldham ring of Figure li;
Figure 15 is a f~ay~ ary sectional view taken substantially along line 15-1~ in Figure 10 showing several of the lubrication pcS~ ways;
Figure 16 is a sectional view taken substantially along line 16-16 in Figure 15;
(. !
Figure 17 is a horizontal sectional view t2ken substantially along line 17-17 in Figure 2;
Figure 18 is an enlarged fragmentary vertical sectional view illustrating another ~mho~iment of the ~es~ L invention;
Figure 19 is a view s;milAr to Figure 18 showing a further ~mho~im~t;
Figure 20 is a f~y,h~ary somewhat di~y~ ,atic horizontal sectional view illustrating a different technique for mounting the o~Liting scroll for limited axial oompliance;
Figure 21 is a sectional view taken subs~ ially along line 21-21 in Figure 20;
Figure 22 is a sectional view si~;lAr to Figure 2~0, but showing a further technique for mounting the non-orbiting scroll for limited axial oompliance;
Figure 23 is a view similar to Figure 20, but illustrating a another technique for mounting the r,o1l olbiting scroll for limited axial oompliance;
Figure 24 is a sectional view taken substantially along line 24-24 in Figure 23;
Figure 25 is simil~r to Figure 20 and illustrates yet a further terh~ique for mounting the non o~biting scroll for limited axial ~,~liance;
Figure 26 is a sectional view taken substantially along line 26-26 in Figure 25;
Figure 27 is ~;m;lAr to Figure 20 and illusLLa~es yet ~oL~e~
te~h~;que for mounting the non o.biting scroll for limited axial oompliance;
~ !
1333~8~
Figure 28 is a sectional view taken substantially along line 28-28 in Figure 27;
Figure 29 is similar to Figure 20 and illustrates yet a further technique for mounting the non-orbiting scroll for limited axial compliance;
Figure 30 is a sectional view taken substantially along line 30-30 in Figure 29:
Figures 31 and 32 are views sim;lAr to Figure 20, illustrating two additional somewhat similar techniqués for mounting the l~on o~biting ~oll for limited axial compliance; and Figure 33 is a view s;m;lAr to Figure 20 illustrating diay~ ically yet another technique for mounting ~he rol. o-biting scroll for limited axial compliance.
DESCRIPTIoN OF THE ~k~Kh~ EMBODIMENTS
Although the principles of the present invention may be applied to many different types of scroll-type machines, they are described herein for exemplary p~l~oses Pmhc~;Pd in a hermetic scroll-type o~l~.ess~l, and particuarly one which has been found to have specific utility in the oompression of refrigerant for air conditioning and refrigeration systems.
With reference to Figures 1-3, the machine comprises three major overall units, i.e. a central ~cs~mhly 10 hol~ce~ within a circular cylindrical steel shell 12, a top _nd bo~,l A-cs~mhl j~s 14 and 16 welded to the upper and lower ends of shell 12, L~s~Lively, to close and seal same. Shell 12 houses the m, jor ~ll~o~ s of the r-^~h;~e, generally including an electric motor 18 having a stator 20 (with conventional ~.~
1333 l~
windinqs 22 and pLo~ec or 23) press fit within shell 12, m~tor rotor 24 (with ~ ional luqs 26) heat shrunk on a crankshaft 28, a o~ ess~
body 30 preferably welded to shell 12 at a plurality of circumferentially spaced locations, as at 32, and supportinq an orbiting scroll memker 34 having a scroll wrap 35 of a standard desired flank profile and a tip surface 33, an upper crankshaft hQArinq 39 of conventional two-piece bearing o~ns~l~ction, a ~ o~biting axially compliant scroll ,.~,~ 36 having a scroll wrap 37 of a standard desired flank profile (preferably the same~as that of scroll wrap 35) meshing with wrap 35 in the usu_l manner and a tip surface 31, a ~;schArge port 41 in scroll member 36, an Oldh_m ring 38 ~ispos~ ~etween scroll nember 34 and body 30 to prevent rotation of scroll member 34, a suction inlet fittinq 40 soldered or welded to shell 12, a directed suction Acs~hly 42 for directinq suction gas to the O~~ eSSGL inlet, and a lower bearinq support bracket 44 welded at each end to shell 10, as at 46, and supportinq a lower crankshaft bearing 48 in which is journaled the lower end of crankshaft 28. The lower end of the oompressor constitutes a sump filled with lubricatinq oil 49.
~ ower Acs~mhly 16 oomprises a simple steel stamping 50 having a plurality of feet 52 and apertured mounting flanges 54. Stamping 50 is ~lded to shell 12, _s at 56, to close and seal the lower end thereof.
Upper assembly 14 is a ~i~ohA~ge muffler comprising a lower stamped steel closure member 58 welded to the upper end of shell 10, as at 60, to close and seal same. Closure member 58 has an u~s ~ding peripheral flange 62 from which projects an apertured holding lug 64 (Figure 3), and in its central area def;n~s an axially ~;sposed circular cylinder chamber 66 having a plurality of openings 68 in the wall 1333~
thereof. To incre~se its stiffness memker 58 is provided with a plurality of embossed or ridged areas 70. An annular gas dicchArge chamber 72 is defined above member 58 by means of an annular muffler member 74 which is welded at its outer periphery to flange 62, as at 76, and at its inner periphery to the outside wall of cylinder chamber 66, as at 78. C~"~ressed gas from ~icrharge port 41 passes through openings 68 into ~hAmhpr 72 from which it is normally ~isrh~rged via a discharge fitting 80 soldered or brazed into the wall of member 74. A
conventional internal pressure relief valve ACS~mhly 82 may be mounted in a suitable opening in closure ,~,~x~ 58 to vent discharge gas into shell 12 in ex oe ssive pressure situations.
Considering in greater detail the major parts of ~he ~ ,~essor, crankshaft 28, which is rotationally driven by motor 18, has at its lower end a reduced diameter bearing surfa oe 84 journaled in bearing 48 and supported on the shoulder above surface 84 by a thrust washer 85 (Figures 1, 2 and 17). The lower end of bearing 48 has an oil inlet passage 86 and a debris removal passage 88. n~ et 44 is formed in the ~hape shown and is provided with ups~a~ side flanges 90 to increase the sLL~ ~Lh and stiffness ~heleof. Eearing 48 is lubricated by immersion in oil 49 and oil is pum~ed to the remainder of the compressor by a c~.lv~l~ional centrifugal crankshaft pump comprising a central oil p~sA~ge 92 and an eccer.tLic, outwardly inçl;ne~, oil feed p~CcAge 94 communicating therewith and extending to the top of the crankshaft. A
transverse p~CsAge 96 extends from pacs~ge 94 to a CiL~ en ial grocve 98 in bearing 39 to lubricate the latter. A lower counterweight 97 and an upper counterweight 100 are afflxed to crankshaft 28 in any suitable manner, such as by staking to projections on lugs 26 in the ) usual manner (n~t shown). These counterweights ~re of conventiona design for a scroll-type machine.
Orbiting scroll member 34 comprises an end plate 102 having generally flat parallel upper and lower surfaces 104 and 106, respectively, the latter slidably engaging a flat circular thrust bearing surface 108 ~ on body 30. Thrust bearing surface 108 is lubricated by an annular groove 110 which receives oil from F~Csage 94 in crankshaft 28 via r~cs~ge 96 and groove 98, the latter communicating with a~.oLhel groove 112 in bearing 39 which feeds oil to intersecting F~c~g~s 114 and 116 in body 30 (Figure 15). m e tips 31 of scroll wrap 37 sealingly engage surface 104, and the tips 33 of scroll wrap 35 in turn sealingly engage a generally flat and parallel ~surface 117 on scroll member 36.
Integrally depending from scroll l~,L~ 34 is a hub 118 having an axial bore 120 therein which has rotatively journaled therein a circular cylindrical unloading drive bushing 122 having an axial bore 124 in B
which is drivingly ~jcpos~ an eccen~Lic crank pin 126 integrally formed ~ ~mf~li4 at the upper end of crankshaft 28. The drive is radially ~ t,~
with crank pin 126 driving bushing 122 via a flat surface 128 on pin l26 which slidably engages a flat bearing insert 130 ~icpose~ in the wall of bore 124. Rotation of crankshaft 28 causes bushing 126 to rotate about the crankshaft axis, which in turn causes scroll ~ L~ 34 to move in a circular orbital path. The angle of the flat driving surface is chosen so that the drive introduces a slight centrifugal force ~ ~ n~ to the orbiting scroll, in order to enhance flank sealing. Bore 124 is cylidrical, but is also slightly oval in cross-sectional shape to permit limited relative sliding movement between the pin and bushing, which ` -1333~
will in turn permit automatic separation and hence unloading of the meshing scroll flanks when liquids or solids are ingested into the o~ essor.
The radially compliant orbital drive of the present invention is lubricated utilizing an improved oil feeding system. Oil is pumped by pump passage 92 to the top of passage 94 from which it is thrown radially outwardly by centrifugal for oe , as indicated by dotted line 125. The oil is collected in a recess in the form of a radial groove 131 located m the top of bushing 122 .along path 125. From here it flows downwardly into the clearance space between pin 126 and bore 124, and between bore 120 and a flat surface 133 on bushing 122 which is aligned with groove 131 (Figure 16). EX oe ss oil then dr~ains to the oil sump 49 via a F~ss~ge 135 in bcdy 30.
Rotation of scroll member 34 relative to body 30 and scroll member 36 is prevented by an Oldham coupling, comprising ring 38 (Figures 13 and 14) which has two downwardly projecting diametrically c~y~s~ integral keys 134 slidably ~ispose~ in diametrically opposed radial slots 136 in body 30, and at 90 degrees therefrom twv upwardly projecting ~ ically l~S~ integral keys 138 slidably ~;spose~ in diametrically q.~lose~ radial slots 140 in scroll member 34 (one of which is shown in Figure 1).
Ring 38 is of a unique configuration whereby it permits the use of a maximum size thrust bearing for a given overal} m.~chine size (in transverse eloss sec~ion), or a m;ni~ size m.~achine for a given size thrust bearinq. miS is accomplished by taking adv~.~age of the fact that the Oldham ring m~ves in a straight line with ~ea~eC~ to the o~"~Lessor bcdy, and thus configuring the ring with a generally oval or 1333~80 "racetrack" shape of minimum inside dimension to clear the peripheral edge of the thrust bearing. m e inside peripheral wall of ring 38, the controlling shape in the present invention, comprises one end 142 of a radius R taken from center x and an opposite end 144 of the same radius R taken from an outer ~ (Figure 13), with the intermediate wall portions being substantially straight, as at 146 and 148. Center points x and y are spaced apart a distance equal to twice the orbital radius of scroll member 34 and are located on a line passing through the centers of keys 134 and radial slots 136, and radiu5 R is equal to the radius of thrust b~ring surface 108 plus a ~lede~ermlned rin;~ cl ance. Except for the shape of ring 38, the Oldham coupling functions in the conventional manner.
One of the more significant aspects of the ~les~-L invention resides in the unique suspension by which upper non-orbiting scroll member is mounted for limited axial mc~ t, while being restrained from any radial or rotational movement, in order to permit axial pressure biasing for tip sealing. m e preferred technique for accomplishing this is best shown in Figures 4-7, 9 and 12. Figure 4 shows the top of the compressor with top ACs~mhly 14 removed, and Figures 5-7 show a p~cyLessive removal of parts. On each side of o~"~Lessor body 30 there are a pair of axially projecting posts 150 having flat upper surfaces lying in a common transverse plane. & roll member 36 has a peripheral flange 152 having a transversely ~;~pose~
planar upper surfa oe , which is ~ æ ess~1 at 154 to accommodate posts 150 (Figures 6 and 7). Posts 150 have axially extending threaded holes 156, and flange 152 has co~es~nding holes 158 equally gpaced from holes 156.
f 13334~
Dispose~ on top of posts 150 is a flat soft metal gasket 160 of the shape shown in Figure 6, on top of gasket 160 is a flat spring steel leaf spring 162 of the shape shown in Figure 5, and on top of that is a retainer 164, all of the these parts being clamped together by threaded fas~e~s 166 threadably ~;~posed in holes 156. The outer ends of spring 162 are affixed to flange 152 by threaded fasteners 168 disposed in holes 158. The opposite side of scroll member 36 is identically supported. As can thus be visualized, scroll member 36 can move slightly in the axial direction by flexing and sLLe~ling (within the elastic limit) springs 162, but cannot rotate or move in the radial ion.
Maximum axial m~ nt of the scroll nembers in a eparating direction is limited by a mechanical stop, i.e. the en~A~ t of flange 152 (see portion 170 in Figures 6, 7 and 12) against the lower surface of spring 162, which is backed-up by retainer 164, and in the opposite d;rection by en~ r -nt of the scroll wrap tips on the end plate of the opposite scroll member. This mer-h~ic~l stop o~e~a~es to cause the oomp esso~ to still compress in the rare situation in which the axial separating force is greater than the axial restoring force, as is the case on start-up. The maximum tip clearance permitted by the stop can be relatively small, e.g. in the order of less than .005" for a scroll to 3n-4" diameter and 1"-2" in wrap height.
Prior to final Ass~mhly scrol} memker 36 is ~Lo~elly aligned with ~es~c~ to body 30 by means of a fixture (not shown) having pins insertable within locating holes 172 on bcdy 30 and locating holes 174 on flange 152. Posts 150 and gasket 160 are provided with ~uLs~ ially Ali~ned edges 176 ~ ose~ generally ~e~ lAr to the portion of `- 1333~80 pring 162 extending thereover, for the purpose of reducing stresses Lhe~ ~ -. Gasket 160 also ~ to distribute the clamping load on spring 162. As shown, spring 162 is in its unstressed condition when the scroll 11~1~ is at its maximum tip clearance condition (i.e. against retainer 164), for ease of manufacture. Pe~u~e the stress in spring 162 is so low for the full range of axial movement, however, the initial essed axial design position of spring 162 is not believed to be critical.
What is very significant, h~v~r, is that the transverse plane in which spring 162 is ~icrosed, as well as the surfaces on the body and n~ll o~iting scroll memker to which it is attached, are disposed substantially in an imaginary transverse plane passing through the mid-point of the meshing scroll wraps, i.e. ap~loAimately mid-way between surfaces 104 and 117. m is enables the mounting means for the axially compliant scroll n~l~eL to minimize the tipping mo~ent on the scroll member caused by the C~ r essed fluid acting in a radial I direction, i.e. the pressure of the oom~less~ gas acting radially against the flanks of the spiral wraps. Failure to h~ e this tipping moment could result in unseating of scroll member 36. This technique for balancinq this force is qreatly superior to the use of the axial pressure biasing her~uce it reduces the possibility of over-biasing the scroll members toqether and hpc~l~ce it also makes tip seal biasing substantially independent of compressor speed. m ere may remain a small tippinq movement due to the fact that the axial separating for oe does not act exactly on the center of the crankshaft, hK~,ev~r it is relatively insignificant compared to the separating and ~e~LvLing forces no~r~ly encountered. There is therefore a distinct advantage in -) 1 3 3 3 ~ ~ ~
axially biasing the non o~iting scroll member, as compared to the orbiting scroll member, in that in the case of the latter it is rCcessAry to ~,~ensate for tipping mc~ s due to radial separating forces, as well as those due to inertial forces, which are a function of speed, and this can result in ex oe ssive balancing forces, particularly at low speeds.
The mounting of scroll .~ e~ 36 for axial compliance in the p~esen~ manner permits the use of a very simple pressure biasing a-~any~,~ to augment tip sealing. With the present invention this is accomplished using pumped fluid at discharge pressure, or at an e~,~diate pressure, or at a pressure refIecting a combination of both. In its simpler and pLes~.~ly preferred form, axiàl biasing in a tip sealing or Les~oLing direction is achieved using dic~hArge pressure.
As best seen in Figures 1-3, the top of scroll member 36 is provided with a cylindrical wall 178 surrounding ~;~chArge port 39 and defining a piston slidably ~;-cpose~ in cylinder chamber 66, an elas~ ric seal 180 being provided to enhance sealing. Scroll member 36 is thus hj~Ced in a ~s~bLing direction by c~ essed fluid at discharge pressure acting on the area of the top of scroll ,~,~x~ 36 defined by piston 178 (less the area of the ~js~hArge port).
FecAIlce the _xial separating force is a function of the A;cchArge pressure of the machine (among other things), it is possible to choose a piston area which will yield excellent tip sealing under most operating conditions. Preferably, the area is c~os~, so that there is no sis~if;cAnt separation of the scroll members at any time in the cycle during normal operating conditions. FL~ . . o~e, optimally in a maximum 1333~8~
pressure situation (maximum separating force) there would be a minimum net axial balancing for oe , and of course no significant ~eparation.
With respect to tip sealing, it has also been discovered that significant perfo~,2nce improvements with a minimum break-in period can be achieved by slightly altering the configuration of end plate surfaces 104 and 117, as well as scroll wrap tip surfaces 31 and 33. It has been learned that it is much preferred to form each of the end plate surfaces 104 and 117 so that they are very slightly concave, and if wrap tip surfaces 31 and 33 are s;~;lArly configured (i.e. surface 31 is t generally parallel to surfa oe 117, and surface 33 is generally parallel to surface 104). This may be contrary to what might be predicted hecAllce it results in an initial distinct axial clearance between the scroll memkers in the central area of the machine, which is the highest pressure area; however it has been found that hPrAll~e the central area is also the hottest, there is more thermal growth in the axial direction in this area which would otherwise result in ~xcPssive efficiency robbing frictional rubbing in the central area of the compressor. By providing this initial extra clearance the com~Lesso- reaches a maximum ' tip sealing condition as it reaches operating temperature.
Although a theoretically smooth concave surface may be better, it has been discovered that the surface can be forrcd having a stepped spiral configuration, which is much easier to machine. As can best be seen in gossly e~y~a~ed form in Figures llA and llB, with reference to Figure 10, surface 104, while being generally flat, is actually formed of spiral stepped surfaces 182, 184, 186 and 188. Tip surface 33 is similarly configured with spiral steps 190, 192, 194 and 196. The individual steps should be as small as possible, with a total 1333~
displacement from flat being a function of scroll wrap height and the thermal coefficient of expansion of the material used.
For example, it has been found that in a three-wrap machine with cast iron scroll members, the ratio of wrap or vane height to total axial surface displacement can range from 3000:1 to 9000:1, with a preferred ratio of approximately 6000:1. Prefer-ably both scroll members will have the same end plate and tip surface configurations, although it is believed possible to put all of the axial surface displacement on one scroll member, if desired. It is not critical where the steps are located because they are 80 small (they cannot even be seen with the naked eye), and because they are 80 small the surfaces in question are referred to as "generally flat". This stepped surface is very different from that of another scroll-type machine in which relatively large steps (with step sealing between the mated scroll members) are provided for increasing the pressure ratio of the machine.
In operation, a cold machine on start-up will have tip sealing at the outer periphery, but an axial clearance in the center area. As the machine reaches operating temperature the axial thermal growth of the central wraps will reduce the axial clearance until good tip sealing is achieved, such sealing being enhanced by pressure biasing as described above. In the absence of such initial axial surface displacement, thermal growth in the center of the machine will cause the outer wraps to axially separate, with 1088 of a good tip seal.
-18a-13334~0 The compressor of the present invention is also provided with improved means for directing suction gas entering the shell directly to the inlet of the compressor itself. ThiS
advantageously facilitates the -18b-~- l33~lsa separation of oil from inlet suction fluid, as well as prevents inlet suction fluid from picking up oil dispersed within the shell interior.
It also prevents the suction gas from picking up ~.fi~ssAry heat from Un~
the motor, which would cause reduction in ve~unc~td-y-efficiency.
A The directed suction A~-cs~ly 42 oomprises a lower baffle element 200 formed of sheet metal and having circumferentially spaced vertical flanges 202 welded to the inside surface of shell 12 (Figures 1, 4, 8 and 10). Baffle 200 is positioned directly over the inlet from suction fitting 40 and is provided with an open bottom portion 204 so that oil carried in the entering suction gas will impinge upon the baffle and then drain into compressor sump 49. The ~cs~ly furth OE comprises a molded plastic element 206 having a ~ ~r~rdly depe~ding integrally formed arcuate shaped channel section 208 extending into a space between the top of baffle 200 and the wall of shell 12, as best seen in Figure 1. The upper portion of element 206 is generally tllh~ r in configuration (diverging radially inwardly) for communicating gas flowing up channel 208 radially inwardly into the p ripheral inlet of the meshed scroll members. Element 208 is retained in place in a circ~,~e~.Lial direction by means of a notch 210 which straddles one of the fasteners 168, and axially by means of an integrally formed tab 212 which is stressed against the lower surface of closure menber 58, as best shown in Figure 1. Tab 212 operates to resiliently bias element 206 axially ~ rdly into the position shown. The radially outer extent of the directed suction inlet ra~a~eway is defined by the inner wall s~rf~ce of shell 12.
Power is supplied to the o~.~Lessol motor in the normal manner using a c~ ional terminal block, ~Lo~ec~ed by a suitable cover 214.
, 1 133~4g~
Several alternative ways in which to achieve pressure biasing in an axial direction to enhance tip se~ are illusLLa~a~ in Figures 18 A ~19 where parts having like functions to those of the first ~o~ nt are indicated with the same reference numerals.
In the ~hc~iment of Figure 18 axial biasing is achieved through the use of c~"~essed fluid at an intenmediate pressure less than ~ hArge pressure. This is Aoco~rlished by providing a piston 300 on the top of scroll member 36 which slides in cylinder ~hAmh~r 66, but which has a closure element 302 preventing ~osl~re of the top of the piston to ~iC~hArge pressure. Instead discharge fluid flows from ~isch~rge port 39 into a radiaI rPc~Age 304 in piston 300 which oDl~ec~s with an annular groove 306, which is in direct com~unication with openings 68 and discharge ~hAmhPr 72. Elastomeric seals 308 and 310 prcvide the necess~ry sealing. Ca"~Lessed fluid under an intermediate pressure is tapped from the desired sealed p x ket defined by the wraps via a p~CsAge 312 to the top of pistons ioo, where it exerts an axial .es~o~ing force on the non-orbiting ccroll member to e~hAn~-e tip Eealing.
In the er~o~imPnt of Figure 19 a oombination of ~i~oh~rge and intermediate pressures are utilized for axial tip seal biasing. To acc~,~lish this, closure memker 58 is ~har~ to define two separate OQAX~A~ SraCe~ cylinder cbambers 314 and 316, and the top of scroll member 36 is provided with cc~xi~l pistons 318 and 320 slidably disposed in ~lu ,~s 314 and 316 ~s~Lively. CbmpLessed fluid under ~ic~Arge pressure is applied to the top of piston 316 in exactly the ~ame manner as in the first er}xlL~nent, and fluid under an intermediate pressure is applied to annular piston 318 via a rAssa~e 322 extending from a 1333~g~
suitably located pressure tap. If desired, piston 320 could be ~ubjected to a second intermediate pressure, ~a~he~ than ~isrhArge pressure. Pec~A~lce the areas of the pistons and the location of the pressure tap can be varied, this ~hcdiment offers the best way to achieve optimum axial balancing for all desired operating conditions.
The pressure taps can be chosen to provide the desired pressure and if des~red can be located to see diLe~ pressures at diLfe~ent points in the cycle, so that an _~e~a~e desired pressure can ke obtained. Pressure r~ss~s 312, 322 and the like are ~,efe~ably relatively small in diameter so that there is a min;~rn of flow (and hence pumping loss~ and a ~mr~n;ng of pressure ~and hence f~rce) variations.
In Figures 20 through 33, there are illustrated a number of other svcFPn~;on systems which have been disc-~vt~ed mounting the non-orbiting scroll member for limited axial mo~ Æ~,~, while restraining same from a radial and circumferential movement. Each of these ~m~c~;ments functions to mount the ~n oLbiting scroll member at its mid-point, as in the first Pm~c~;ment, so as to hp~An~e the ~ ;n~ mDments on the scroll memher cleaLed by radial fluid ~.es~uLe forces. In all of these em~xxluments, the top surface of flange 152 i8 in the same 9~ -Llical position as in the first emkadiment.
" With ~fe~ence to Figures 20 and` 21, D~l~yOL~ iS maintained by means of a spring steel ring 400 ~ oL~ at its outer p_riphery by n~ans of faster.ers 402 to a ~ur.ting ring 404 affixed to the inside surface of shell 12, and at its ir.side periphery to the ~er surface of flange 152 c~ "on oll,iting scroll m~rber 36 ~y means of asL~--e~s 406.
Rir~ 400 is provided wi~ a plurality of anS~led c~Pn;~s 408 ~i~posed 1333~80 about the full ext~ent thereof to reduce the stiffness thereof and permit limited axial excursions of the no~ o~Liting scroll member 36. PecA~lce cpenings 408 are slanted with Le~ cL to the rA~iAl direction, axial displa oe ment of the inner periphery of the ring with ~s~L to the outer periphery heleof ~not require ~L~t~ nq of the ring, but will cause a very slight rotation. This very limited rotational m n~ment is so trivial, hK~.evcr, that it is not believed it causes any significant loss of efficiency.
In the Pr~c~iment of Figure 22, 1~1. oLbitinq scroll 36 is very ~imply mounted by means of a plurality of Lr~re~ ~Lac~c~s 410 welded on one leg to the inner surface of shell 12 and having the other leg affixed to the upper surface of flange 152 by n~u~s of a ~uitable fastener 412. Bracket 410 is desiqned so that it may sLLe~ch sliqhtly within its elastic limit to Ac~ te axial excursions of the o~biting scroll.
In the ~ko~;m~nts of Fiqures 23 and 24, the mounting means comprises a plurality (three shown) of ~lhlllAr members 414 having a radially inner flange structure 416 affixed to the top ~urface of flange 152 of the Ib~ oLbiting scroll by means of a ~uitable ~s~ ~ 418, and a radially outer flanqe 420 o~.u ~ La~ by means of a suitable fas~,e~
422 to a ~ac~e~ 424 ~ P~ to the ;~cide ~rf~ oe of shell 12. Radial exoursions of the l~ Lbiting scroll are ~.ev~ e!d by virtue of the fact that there are a plurality of ~llhl~l~r members u~ e~ with at least two of them not dire!ctly opposi~ one ~x~LheL.
In the emho~ment of Figures 25 and 26, the lX~ Liting scroll is supported for limited axial .~.~ by means of leaf springs 426 and 428 which are affixed at their outer ends to a mounting ring 430 welded 13334~0 ;
to the inside surface of shell 12 by suitable fas~ene~s 432, and to the upper surface of flange 152 in the center Lhe~e~r by means of a ~uitable fastener 434. The leaf springs can either be straight, as in the case of spring 426, or arcuate, as in the case of spring 428. Slight axial excursions of scroll ._,L~ 36 will cause sL.e~.ing of the leaf springs within their elastic limit.
In the er~QdimPnt of Figures 27 and 28 radial and circumferential movement of ~lol~ o~biting scroll 36 is prevented by a plurality of spherical balls 436 (one shown) tightly fit within a cylindrical bore defined by a cylindrical surfa oe 43~ on the inner peripheral edge of a mounting ring 440 ~ e~ to the inside surface of shell 12 and by a cylindrical surfa oe 439 formed in the radially outer peripheral edge of 4~
a flange ~ on ~ biting scroll member 36, the balls 436 lying in a plane ~;s~osed midway between the end plate surfaces of the scroll .~ ~e s for the reasons discussed above. m e ~mho~;~.rnt of Figures 29 and 30 is virtually identical to that of Figures 27 and 28 except instead of balls, there are ut;lj7~d a plurality of circular cylindrical rollers 444 ~one of which is shcwn) tightly ~.~ssed within a ~e~Lar~lar slot defined by surface 446 on ring 440 and surface 448 on flange 442.
Preferably ring 440 is sufficientlyl resilient that it can be stLe~led over the balls or rollers in order to ~,~ sLLess the ~cse~hly and eliminate any backlash.
In the em~c~;m~nt of Figure 31, the orbiting scroll 36 is provided with a centrally ~;~rosçd flange 450 having an axially ~xL~ding hole 452 extending th~eL~.-ough. S~ qly ~crQse~ within hole 452 is a pin 454 tightly affixed at its lower end to bcdy 30. As can be ~isualized, axial exc~rsions of the ~ o~iting scroll are 1333~0 possible whereas circ~,~e~tial or radial excursions are prevented.
The ~mhc~;mPnt of Figure 32 is identical to that of Figure 1 except that pin 454 is adjustable. mis is accomplished by providing an enlarged hole 456 in a suitable flange on body 30 and providing pin 4S4 with a Cupport flange 458 and a threaded lower end projecting through hole 456 and having a threaded nut 460 thereon. Once pin 454 is accurately positioned, nut 460 is tightened to pe~"~)en-ly anchor the parts in position.
In the P~ho~im~t of Figure 33, the lnside ~rface of shell 12 is provided with two bosses 462 and 464 having accurat~ely m~ch;n~d, radially inwardly facing flat surfaces 466 and 468, l~5~t~ ively, -cposed at right angles with respect to one another.. Flange 152 on ~ o~biting scroll 36 is provided with two corresponding bosses each having radially outwardly facing flat surfaces 470 and 472 located at right angles with respect to one another and engaging surfaces 466 and 468, respectively. These bosses and surfaces are accurately machined so as to properly locate the lon o~Biting scroll in the proper radial and rotational position. To maintain it in that position while permitting limited axial movement thereof there is provided a very stiff spring in the form of a Belleville washer or the like 474 acting~ n a boss 476 on the inner surface of shell 12 and a boss 478 ~ffiY~1 to the outer periphery of flange 152. Spring 484 applies a strong biasing force against the non-orbiting scroll to maintain it in position against surfaces 466 and 468. This force should be slightly greater than the maximum radial and rotational force normally enco~.~_L~d tending to unseat the scroll member. Spring 474 is preferably positioned so that the ~iasing force it exerts has equal components in the direction of each of hosses 462 and 464 ~i.e., its diametrical force line bisects the two bosses). As in the previous ~mhC~iments~ the hosses and spring force are ~jspose~ substantially midway between the scroll member end plate surfaces, in order to balance tipping moments.
In all of the ~mhc~ nts of Figures 20 through 33 it should be a~ æ iated that axial movement of the llOl~ oL~iting scrolls in a ~separating direction can be limited by any suitable means, such as the mechanical stop described in the first embodiment. Mk~ ~n~ in the opposite direction is, of course, lim~ted by the ~1~J~J-~ent of the scroll m~ ~eLs with one anoL~.eL.
While it will be apparent that the ~L~feLLed embcdiments of the invention disclosed are well calculated to provide the advantages and features above stated, it will be a~.eoiated that the invention is sllsceptible to modification, variation and rhA~e without departing from the ~-o~e~ scope or fair meaning of the subjoined claims.
Claims (40)
1. A scroll-type machine comprising:
(a) A first scroll member having a spiral wrap thereon;
(b) a second scroll member having a spiral wrap thereon;
(c) support means for mounting said scroll members with said spiral wraps intermeshing with one another, said first scroll member being mounted for non-orbital movement with respect to said support means, and said second scroll member being mounted for orbital movement with respect to said first scroll member whereby said orbital movement will cause said wraps to define moving fluid pockets communicating between a low pressure and a high pressure;
and (d) biasing means for biasing said first scroll member toward said second scroll member, said biasing means comprising means defining a first chamber containing fluid at a first pressure; and means defining a second chamber containing a fluid at a second pressure;
said first and second pressures being greater than said low pressure;
said first and second chambers being positioned such that said fluid at said first pressure and said fluid at said second pressure cooperate to exert a biasing force on said first scroll member in a direction toward said second scroll member and generally parallel to the axis of said orbital movement to thereby enhance sealing therebetween.
(a) A first scroll member having a spiral wrap thereon;
(b) a second scroll member having a spiral wrap thereon;
(c) support means for mounting said scroll members with said spiral wraps intermeshing with one another, said first scroll member being mounted for non-orbital movement with respect to said support means, and said second scroll member being mounted for orbital movement with respect to said first scroll member whereby said orbital movement will cause said wraps to define moving fluid pockets communicating between a low pressure and a high pressure;
and (d) biasing means for biasing said first scroll member toward said second scroll member, said biasing means comprising means defining a first chamber containing fluid at a first pressure; and means defining a second chamber containing a fluid at a second pressure;
said first and second pressures being greater than said low pressure;
said first and second chambers being positioned such that said fluid at said first pressure and said fluid at said second pressure cooperate to exert a biasing force on said first scroll member in a direction toward said second scroll member and generally parallel to the axis of said orbital movement to thereby enhance sealing therebetween.
2. A scroll-type machine as claimed in claim 1, wherein said machine is a compressor for pumping fluid from a relatively low suction pressure to a relatively high discharge pressure
3. A scroll-type machine as claimed in claim 2, wherein one of said first and second pressures is said discharge pressure.
4. A scroll-type machine as claimed in claim 2, wherein one of said first and second pressures is a pressure intermediate said suction and discharge pressures.
26a
26a
5. A scroll-type machine as claimed in claim 2, wherein said first pressure is said discharge pressure and said second pressure is intermediate said suction and discharge pressures.
6. A scroll-type machine as claimed in claim 2, wherein said one of said first and second chambers comprises a first cylinder chamber mounted in a fixed position with respect to said support means, and a first piston connected to one of said scroll members, said first piston being slidably disposed in said first cylinder chamber for movement with respect thereto in a direction substantially parallel to said axis.
7. A scroll-type machine as claimed in claim 6, wherein said other of said first and second chambers comprises a second cylinder chamber mounted in a fixed position with respect to said support means, and a second piston connected to one of said scroll members, said second piston being slidably disposed in said second cylinder chamber for movement with respect thereto in a direction substantially parallel to said axis.
8. A scroll-type machine as claimed in claim 7, wherein said cylinder chambers and pistons are generally concentric with respect to one another, said cylinder chambers being defined by a stepped cylinder wall having two different inside diameters, said second piston being defined by an annular shoulder on said first piston, said first piston being surrounded by the smaller diameter portion of said cylinder wall, said second piston being surrounded by the larger diameter portion of said cylinder wall.
9. A scroll-type machine as claimed in claim 7, wherein said first and second pistons are connected to said one of said scroll members.
10. A scroll-type machine as claimed in claim 6, further comprising means for communicating pressurized fluid at a pressure intermediate said discharge pressure and said suction pressure to the head end of said piston to bias said scroll members together.
11. A scroll-type machine as claimed in claim 1, wherein said biasing means acts against only one of said scroll members.
12. A scroll-type machine as claimed in claim 2, wherein one of said scroll members includes passage means for conducting pump fluid from one of said pockets at a pressure intermediate said suction and discharge pressures to one of said chambers.
13. A scroll-type machine as claimed in claim 12, further comprising second passage means for conducting fluid at discharge pressure to the other of said chambers.
14. A scroll-type machine as claimed in claim 13, wherein said first and second passages are provided in the same scroll member.
15. A scroll-type machine as claimed in claim 1, wherein said fluids at said first and second pressures act against an axially facing surface of one of said scroll members.
16. A scroll-type machine as claimed in claim 1, wherein said first scroll member is mounted for non-orbital movement with respect to said support means and said second scroll member is mounted for orbital movement with respect to said support means, the fluid in at least one of said chambers causing a biasing force to be applied directly to said first scroll member.
17. A scroll-type machine as claimed in claim 16, wherein the fluid in both said chambers causes a biasing force to be applied directly to said first scroll member.
18. A scroll-type machine as claimed in claim 1, wherein said chambers are concentric with one another.
19. A scroll-type machine as claimed in claim 18, wherein each of said chambers is partially defined by an exposed surface on one of said scroll members.
20. A scroll-type machine as claimed in claim 19, wherein said exposed surfaces are on the same scroll member.
21. A scroll-type machine as claimed in claim 20, further comprising annular elastomeric sealing means disposed between said chambers.
22. A scroll-type machine as claimed in claim 1, wherein said scroll machine is a compressor for pumping fluid from a relatively low suction pressure to a relatively high discharge pressure, one of said chambers being in fluid communication with said discharge pressure and the other of said chambers being in fluid communication with one of said pockets at a pressure intermediate said suction and discharge pressures.
23. A scroll-type machine as claimed in claim 2 wherein said one of said first and second chambers comprises a first cylinder chamber, and a first piston said first piston being slidably disposed in said first cylinder chamber for movement with respect thereto in a direction substantially parallel to said axis.
24. A scroll-type machine as claimed in claim 23 wherein said first cylinder chamber is mounted in a fixed position with respect to said support means.
25. A scroll-type machine as claimed in claim 24 wherein said first piston is connected to one of said scroll members.
26. A scroll-type machine as claimed in claim 23 wherein said other of said first and second chambers comprises a second cylinder chamber, and a second piston, said second piston being slidably disposed in said second cylinder chamber for movement with respect thereto in a direction substantially parallel to said axis.
27. A scroll-type machine as claimed in claim 26 wherein said second cylinder chamber is mounted in a fixed position with respect to said support means.
28. A scroll-type machine as claimed in claim 27 wherein said second piston is connected to one of said scrolls.
29. A scroll-type machine as claimed in claim 1 wherein said fluids at said first and second pressures act against an axially facing surface of said first scroll member.
30. A scroll-type machine as claimed in claim 29 wherein said fluids act directly against said axially facing surface.
31. A scroll-type machine as claimed in claim 29 further comprising an elastomeric seal separating the surface of said first scroll member which receives said first pressure from the surface of said first scroll member which receives said second pressure.
32. A scroll-type machine as claimed in claim 31 further comprising a second elastomeric seal separating one of said surfaces which receives said first and second pressures from an area which receives said low pressure.
33. A scroll-type machine as claimed in claim 1 wherein said support means include axially complaint mounting means operative to permit limited axial movement of said first scroll member with respect to said support means.
34. A scroll-type machine as claimed in claim 33 wherein said axially compliant mounting means includes means defining an axially facing surface engageable with a corresponding opposite axially facing surface provided on said first scroll member, said scroll member surface being positioned generally at the mid-point between the axially opposite ends of said spiral wrap.
35. A scroll-type machine as claimed in claim 1 wherein said mounting means includes a stationary body supporting said second scroll member for orbital movement, said biasing means acting to bias said first and second scroll members against said stationary body.
36. A scroll-type machine as claimed in claim 35 further comprising an outer shell, said stationary body being secured to the inner walls of said shell and contains beaning means for supporting a drive shaft operative to drive said second scroll member in orbital movement with respect to said body.
37. A scroll-type machine as claimed in claim 30 further including motor means disposed within said shell for driving said second scroll member, said motor means including a stator supported by said inner walls and a rotor secured to said drive shaft and supported by said stationary body.
38. A scroll-type machine as claimed in claim 37 further including axially complaint mounting means for mounting said first scroll member on said stationary body, said axially compliant mounting means being operative to limit axial movement of said first scroll member in a direction away from said first scroll member.
39. A scroll-type compressor comprising:
(a) a first scroll member having a spiral wrap thereon;
(b) a second scroll member having a spiral wrap thereon, (c) support means for mounting said scroll members with said spiral wraps intermeshing with one another, said first scroll member being mounted for non-orbital movement with respect to said support means, and said second scroll member being mounted for orbital movement with respect to said first scroll member whereby said orbital movement will cause said wraps to define moving fluid pockets operative to pump and compress fluid from a relatively low suction pressure to a relatively high discharge pressure;
(d) biasing means for biasing said first scroll member toward said second scroll member, said biasing means comprising means defining a first chamber containing fluid at a first pressure; and means defining a second chamber containing a fluid at a second pressure;
said first and second pressures being greater than said low suction pressure;
said first and second chambers being positioned such that said fluid at said first pressure and said fluid at said second pressure act directly on surfaces of said first scroll member to exert a biasing force thereon in a direction toward said second scroll member and generally parallel to the axis of said orbital movement to thereby enhance sealing therebetween.
(a) a first scroll member having a spiral wrap thereon;
(b) a second scroll member having a spiral wrap thereon, (c) support means for mounting said scroll members with said spiral wraps intermeshing with one another, said first scroll member being mounted for non-orbital movement with respect to said support means, and said second scroll member being mounted for orbital movement with respect to said first scroll member whereby said orbital movement will cause said wraps to define moving fluid pockets operative to pump and compress fluid from a relatively low suction pressure to a relatively high discharge pressure;
(d) biasing means for biasing said first scroll member toward said second scroll member, said biasing means comprising means defining a first chamber containing fluid at a first pressure; and means defining a second chamber containing a fluid at a second pressure;
said first and second pressures being greater than said low suction pressure;
said first and second chambers being positioned such that said fluid at said first pressure and said fluid at said second pressure act directly on surfaces of said first scroll member to exert a biasing force thereon in a direction toward said second scroll member and generally parallel to the axis of said orbital movement to thereby enhance sealing therebetween.
40. A scroll-type machine comprising:
(a) a first scroll member having a spiral wrap thereon;
(b) a second scroll member having a spiral wrap thereon;
(c) support means for mounting said scroll members for relative orbital movement with said spiral wraps intermeshing with one another whereby said orbital movement will cause said wraps to define moving fluid pockets; and (d) biasing means for biasing said first and second scroll members toward one another, said biasing means comprising:
means defining a first cylinder chamber containing fluid at a first pressure operative to bias a first piston movably disposed therein; and means defining a second cylinder chamber containing a fluid at a second pressure and operative to bias a second piston movably disposed in said second cylinder chamber;
one of said cylinder chambers and pistons being provided on one of said scroll members and the other of said cylinder chambers and pistons being mounted in a fixed position with respect to said support means, said cylinder chambers and pistons being generally concentric with respect to one another, said cylinder chambers being defined by a stepped cylinder wall having two different inside diameters, said second piston being defined by an annular shoulder on said first piston, said first piston being surrounded by the smaller diameter portion of said cylinder wall, said second piston being surrounded by the larger diameter portion of said cylinder wall, said first and second chambers being positioned such that said fluid at said first pressure and said fluid at said second pressure cooperate to bias said first and said second scroll members toward one another in a direction generally parallel to the axis of said orbital movement to thereby enhance sealing therebetween.
(a) a first scroll member having a spiral wrap thereon;
(b) a second scroll member having a spiral wrap thereon;
(c) support means for mounting said scroll members for relative orbital movement with said spiral wraps intermeshing with one another whereby said orbital movement will cause said wraps to define moving fluid pockets; and (d) biasing means for biasing said first and second scroll members toward one another, said biasing means comprising:
means defining a first cylinder chamber containing fluid at a first pressure operative to bias a first piston movably disposed therein; and means defining a second cylinder chamber containing a fluid at a second pressure and operative to bias a second piston movably disposed in said second cylinder chamber;
one of said cylinder chambers and pistons being provided on one of said scroll members and the other of said cylinder chambers and pistons being mounted in a fixed position with respect to said support means, said cylinder chambers and pistons being generally concentric with respect to one another, said cylinder chambers being defined by a stepped cylinder wall having two different inside diameters, said second piston being defined by an annular shoulder on said first piston, said first piston being surrounded by the smaller diameter portion of said cylinder wall, said second piston being surrounded by the larger diameter portion of said cylinder wall, said first and second chambers being positioned such that said fluid at said first pressure and said fluid at said second pressure cooperate to bias said first and said second scroll members toward one another in a direction generally parallel to the axis of said orbital movement to thereby enhance sealing therebetween.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000616406A CA1333480C (en) | 1986-08-22 | 1992-06-15 | Scroll machine with plural pressurized seal enhancing chambers and static vane mounts |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US899,003 | 1986-08-22 | ||
| US06/899,003 US4767293A (en) | 1986-08-22 | 1986-08-22 | Scroll-type machine with axially compliant mounting |
| CA000544673A CA1311729C (en) | 1986-08-22 | 1987-08-17 | Scroll machine with plural pressurized seal enhancing chambers and static vane mounts |
| CA000616406A CA1333480C (en) | 1986-08-22 | 1992-06-15 | Scroll machine with plural pressurized seal enhancing chambers and static vane mounts |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000544673A Division CA1311729C (en) | 1986-08-22 | 1987-08-17 | Scroll machine with plural pressurized seal enhancing chambers and static vane mounts |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1333480C true CA1333480C (en) | 1994-12-13 |
Family
ID=25671473
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000616406A Expired - Lifetime CA1333480C (en) | 1986-08-22 | 1992-06-15 | Scroll machine with plural pressurized seal enhancing chambers and static vane mounts |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1333480C (en) |
-
1992
- 1992-06-15 CA CA000616406A patent/CA1333480C/en not_active Expired - Lifetime
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| Date | Code | Title | Description |
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| MKEX | Expiry |